gcc: Fix CVE-2021-42574

Upstream-Status: Backport [https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=004bb936d6d5f177af26ad4905595e843d5665a5]
Upstream-Status: Backport [https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=bd5e882cf6e0def3dd1bc106075d59a303fe0d1e]
Upstream-Status: Backport [https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=51c500269bf53749b107807d84271385fad35628]
Upstream-Status: Backport [https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=1a7f2c0774129750fdf73e9f1b78f0ce983c9ab3]
Upstream-Status: Backport [https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=bef32d4a28595e933f24fef378cf052a30b674a7]

(From OE-Core rev: d0f4614e2c6e9090a0c45052c36d0c7f3215de10)

Signed-off-by: pgowda <pgowda.cve@gmail.com>
Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

6 files changed, 7618 insertions, 0 deletions

diff --git a/meta/recipes-devtools/gcc/gcc-10.2.inc b/meta/recipes-devtools/gcc/gcc-10.2.inc
index 89158258d7..656c43258c 100644
--- a/meta/recipes-devtools/gcc/gcc-10.2.inc
+++ b/meta/recipes-devtools/gcc/gcc-10.2.inc
@@ -75,6 +75,11 @@ SRC_URI = "\
            file://0003-CVE-2021-35465.patch \
            file://0004-CVE-2021-35465.patch \
            file://0039-arm64-neoverse-n2-support.patch \
+           file://0001-CVE-2021-42574.patch \
+           file://0002-CVE-2021-42574.patch \
+           file://0003-CVE-2021-42574.patch \
+           file://0004-CVE-2021-42574.patch \
+           file://0005-CVE-2021-42574.patch \
 "
 SRC_URI[sha256sum] = "b8dd4368bb9c7f0b98188317ee0254dd8cc99d1e3a18d0ff146c855fe16c1d8c"
 
diff --git a/meta/recipes-devtools/gcc/gcc/0001-CVE-2021-42574.patch b/meta/recipes-devtools/gcc/gcc/0001-CVE-2021-42574.patch
new file mode 100644
index 0000000000..e0f4f7d32f
--- /dev/null
+++ b/meta/recipes-devtools/gcc/gcc/0001-CVE-2021-42574.patch
@@ -0,0 +1,2906 @@
+From 004bb936d6d5f177af26ad4905595e843d5665a5 Mon Sep 17 00:00:00 2001
+From: Lewis Hyatt <lhyatt@gmail.com>
+Date: Tue, 14 Jul 2020 12:05:56 -0400
+Subject: [PATCH] diagnostics: Support conversion of tabs to spaces [PR49973]
+ [PR86904]
+
+Supports conversion of tabs to spaces when outputting diagnostics. Also
+adds -fdiagnostics-column-unit and -fdiagnostics-column-origin options to
+control how the column number is output, thereby resolving the two PRs.
+
+gcc/c-family/ChangeLog:
+
+        PR other/86904
+        * c-indentation.c (should_warn_for_misleading_indentation): Get
+        global tabstop from the new source.
+        * c-opts.c (c_common_handle_option): Remove handling of -ftabstop, which
+        is now a common option.
+        * c.opt: Likewise.
+
+gcc/ChangeLog:
+
+        PR preprocessor/49973
+        PR other/86904
+        * common.opt: Handle -ftabstop here instead of in c-family
+        options.  Add -fdiagnostics-column-unit= and
+        -fdiagnostics-column-origin= options.
+        * opts.c (common_handle_option): Handle the new options.
+        * diagnostic-format-json.cc (json_from_expanded_location): Add
+        diagnostic_context argument.  Use it to convert column numbers as per
+        the new options.
+        (json_from_location_range): Likewise.
+        (json_from_fixit_hint): Likewise.
+        (json_end_diagnostic): Pass the new context argument to helper
+        functions above.  Add "column-origin" field to the output.
+        (test_unknown_location): Add the new context argument to calls to
+        helper functions.
+        (test_bad_endpoints): Likewise.
+        * diagnostic-show-locus.c
+        (exploc_with_display_col::exploc_with_display_col): Support
+        tabstop parameter.
+        (layout_point::layout_point): Make use of class
+        exploc_with_display_col.
+        (layout_range::layout_range): Likewise.
+        (struct line_bounds): Clarify that the units are now always
+        display columns.  Rename members accordingly.  Add constructor.
+        (layout::print_source_line): Add support for tab expansion.
+        (make_range): Adapt to class layout_range changes.
+        (layout::maybe_add_location_range): Likewise.
+        (layout::layout): Adapt to class exploc_with_display_col changes.
+        (layout::calculate_x_offset_display): Support tabstop parameter.
+        (layout::print_annotation_line): Adapt to struct line_bounds changes.
+        (layout::print_line): Likewise.
+        (line_label::line_label): Add diagnostic_context argument.
+        (get_affected_range): Likewise.
+        (get_printed_columns): Likewise.
+        (layout::print_any_labels): Adapt to struct line_label changes.
+        (class correction): Add m_tabstop member.
+        (correction::correction): Add tabstop argument.
+        (correction::compute_display_cols): Use m_tabstop.
+        (class line_corrections): Add m_context member.
+        (line_corrections::line_corrections): Add diagnostic_context argument.
+        (line_corrections::add_hint): Use m_context to handle tabstops.
+        (layout::print_trailing_fixits): Adapt to class line_corrections
+        changes.
+        (test_layout_x_offset_display_utf8): Support tabstop parameter.
+        (test_layout_x_offset_display_tab): New selftest.
+        (test_one_liner_colorized_utf8): Likewise.
+        (test_tab_expansion): Likewise.
+        (test_diagnostic_show_locus_one_liner_utf8): Call the new tests.
+        (diagnostic_show_locus_c_tests): Likewise.
+        (test_overlapped_fixit_printing): Adapt to helper class and
+        function changes.
+        (test_overlapped_fixit_printing_utf8): Likewise.
+        (test_overlapped_fixit_printing_2): Likewise.
+        * diagnostic.h (enum diagnostics_column_unit): New enum.
+        (struct diagnostic_context): Add members for the new options.
+        (diagnostic_converted_column): Declare.
+        (json_from_expanded_location): Add new context argument.
+        * diagnostic.c (diagnostic_initialize): Initialize new members.
+        (diagnostic_converted_column): New function.
+        (maybe_line_and_column): Be willing to output a column of 0.
+        (diagnostic_get_location_text): Convert column number as per the new
+        options.
+        (diagnostic_report_current_module): Likewise.
+        (assert_location_text): Add origin and column_unit arguments for
+        testing the new functionality.
+        (test_diagnostic_get_location_text): Test the new functionality.
+        * doc/invoke.texi: Document the new options and behavior.
+        * input.h (location_compute_display_column): Add tabstop argument.
+        * input.c (location_compute_display_column): Likewise.
+        (test_cpp_utf8): Add selftests for tab expansion.
+        * tree-diagnostic-path.cc (default_tree_make_json_for_path): Pass the
+        new context argument to json_from_expanded_location().
+
+libcpp/ChangeLog:
+
+        PR preprocessor/49973
+        PR other/86904
+        * include/cpplib.h (struct cpp_options):  Removed support for -ftabstop,
+        which is now handled by diagnostic_context.
+        (class cpp_display_width_computation): New class.
+        (cpp_byte_column_to_display_column): Add optional tabstop argument.
+        (cpp_display_width): Likewise.
+        (cpp_display_column_to_byte_column): Likewise.
+        * charset.c
+        (cpp_display_width_computation::cpp_display_width_computation): New
+        function.
+        (cpp_display_width_computation::advance_display_cols): Likewise.
+        (compute_next_display_width): Removed and implemented this
+        functionality in a new function...
+        (cpp_display_width_computation::process_next_codepoint): ...here.
+        (cpp_byte_column_to_display_column): Added tabstop argument.
+        Reimplemented in terms of class cpp_display_width_computation.
+        (cpp_display_column_to_byte_column): Likewise.
+        * init.c (cpp_create_reader): Remove handling of -ftabstop, which is now
+        handled by diagnostic_context.
+
+gcc/testsuite/ChangeLog:
+
+        PR preprocessor/49973
+        PR other/86904
+        * c-c++-common/Wmisleading-indentation-3.c: Adjust expected output
+        for new defaults.
+        * c-c++-common/Wmisleading-indentation.c: Likewise.
+        * c-c++-common/diagnostic-format-json-1.c: Likewise.
+        * c-c++-common/diagnostic-format-json-2.c: Likewise.
+        * c-c++-common/diagnostic-format-json-3.c: Likewise.
+        * c-c++-common/diagnostic-format-json-4.c: Likewise.
+        * c-c++-common/diagnostic-format-json-5.c: Likewise.
+        * c-c++-common/missing-close-symbol.c: Likewise.
+        * g++.dg/diagnostic/bad-binary-ops.C: Likewise.
+        * g++.dg/parse/error4.C: Likewise.
+        * g++.old-deja/g++.brendan/crash11.C: Likewise.
+        * g++.old-deja/g++.pt/overload2.C: Likewise.
+        * g++.old-deja/g++.robertl/eb109.C: Likewise.
+        * gcc.dg/analyzer/malloc-paths-9.c: Likewise.
+        * gcc.dg/bad-binary-ops.c: Likewise.
+        * gcc.dg/format/branch-1.c: Likewise.
+        * gcc.dg/format/pr79210.c: Likewise.
+        * gcc.dg/plugin/diagnostic-test-expressions-1.c: Likewise.
+        * gcc.dg/plugin/diagnostic-test-string-literals-1.c: Likewise.
+        * gcc.dg/redecl-4.c: Likewise.
+        * gfortran.dg/diagnostic-format-json-1.F90: Likewise.
+        * gfortran.dg/diagnostic-format-json-2.F90: Likewise.
+        * gfortran.dg/diagnostic-format-json-3.F90: Likewise.
+        * go.dg/arrayclear.go: Add a comment explaining why adding a
+        comment was necessary to work around a dejagnu bug.
+        * c-c++-common/diagnostic-units-1.c: New test.
+        * c-c++-common/diagnostic-units-2.c: New test.
+        * c-c++-common/diagnostic-units-3.c: New test.
+        * c-c++-common/diagnostic-units-4.c: New test.
+        * c-c++-common/diagnostic-units-5.c: New test.
+        * c-c++-common/diagnostic-units-6.c: New test.
+        * c-c++-common/diagnostic-units-7.c: New test.
+        * c-c++-common/diagnostic-units-8.c: New test.
+
+CVE: CVE-2021-42574
+Upstream-Status: Backport [https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=004bb936d6d5f177af26ad4905595e843d5665a5]
+Signed-off-by: Pgowda <pgowda.cve@gmail.com>
+---
+ gcc/c-family/c-indentation.c                  |   5 +-
+ gcc/c-family/c-opts.c                         |   6 -
+ gcc/c-family/c.opt                            |   4 -
+ gcc/common.opt                                |  21 +
+ gcc/diagnostic-format-json.cc                 |  55 +-
+ gcc/diagnostic-show-locus.c                   | 504 +++++++++++++-----
+ gcc/diagnostic.c                              | 113 +++-
+ gcc/diagnostic.h                              |  28 +-
+ gcc/doc/invoke.texi                           |  68 ++-
+ gcc/input.c                                   |  72 ++-
+ gcc/input.h                                   |   4 +-
+ gcc/opts.c                                    |  14 +
+ .../c-c++-common/Wmisleading-indentation-3.c  |  12 +-
+ .../c-c++-common/Wmisleading-indentation.c    |   6 +-
+ .../c-c++-common/diagnostic-format-json-1.c   |   5 +
+ .../c-c++-common/diagnostic-format-json-2.c   |   5 +
+ .../c-c++-common/diagnostic-format-json-3.c   |   5 +
+ .../c-c++-common/diagnostic-format-json-4.c   |   9 +
+ .../c-c++-common/diagnostic-format-json-5.c   |   9 +
+ .../c-c++-common/diagnostic-units-1.c         |  28 +
+ .../c-c++-common/diagnostic-units-2.c         |  28 +
+ .../c-c++-common/diagnostic-units-3.c         |  28 +
+ .../c-c++-common/diagnostic-units-4.c         |  28 +
+ .../c-c++-common/diagnostic-units-5.c         |  28 +
+ .../c-c++-common/diagnostic-units-6.c         |  28 +
+ .../c-c++-common/diagnostic-units-7.c         |  28 +
+ .../c-c++-common/diagnostic-units-8.c         |  28 +
+ .../c-c++-common/missing-close-symbol.c       |   6 +-
+ .../g++.dg/diagnostic/bad-binary-ops.C        |   8 +-
+ gcc/testsuite/g++.dg/parse/error4.C           |   2 +-
+ .../g++.old-deja/g++.brendan/crash11.C        |   4 +-
+ gcc/testsuite/g++.old-deja/g++.pt/overload2.C |   2 +-
+ .../g++.old-deja/g++.robertl/eb109.C          |   4 +-
+ .../gcc.dg/analyzer/malloc-paths-9.c          |   2 +-
+ gcc/testsuite/gcc.dg/bad-binary-ops.c         |   8 +-
+ gcc/testsuite/gcc.dg/format/branch-1.c        |   2 +-
+ gcc/testsuite/gcc.dg/format/pr79210.c         |   2 +-
+ .../plugin/diagnostic-test-expressions-1.c    |  16 +-
+ .../diagnostic-test-string-literals-1.c       |   4 +-
+ gcc/testsuite/gcc.dg/redecl-4.c               |   2 +-
+ .../gfortran.dg/diagnostic-format-json-1.F90  |   5 +
+ .../gfortran.dg/diagnostic-format-json-2.F90  |   5 +
+ .../gfortran.dg/diagnostic-format-json-3.F90  |   5 +
+ gcc/testsuite/go.dg/arrayclear.go             |   3 +
+ gcc/tree-diagnostic-path.cc                   |   5 +-
+ libcpp/charset.c                              |  98 ++--
+ libcpp/include/cpplib.h                       |  40 +-
+ libcpp/init.c                                 |   1 -
+ 48 files changed, 1106 insertions(+), 287 deletions(-)
+ create mode 100644 gcc/testsuite/c-c++-common/diagnostic-units-1.c
+ create mode 100644 gcc/testsuite/c-c++-common/diagnostic-units-2.c
+ create mode 100644 gcc/testsuite/c-c++-common/diagnostic-units-3.c
+ create mode 100644 gcc/testsuite/c-c++-common/diagnostic-units-4.c
+ create mode 100644 gcc/testsuite/c-c++-common/diagnostic-units-5.c
+ create mode 100644 gcc/testsuite/c-c++-common/diagnostic-units-6.c
+ create mode 100644 gcc/testsuite/c-c++-common/diagnostic-units-7.c
+ create mode 100644 gcc/testsuite/c-c++-common/diagnostic-units-8.c
+
+diff --git a/gcc/c-family/c-indentation.c b/gcc/c-family/c-indentation.c
+--- a/gcc/c-family/c-indentation.c      2020-07-22 23:35:17.296384022 -0700
++++ b/gcc/c-family/c-indentation.c      2021-12-25 01:20:53.475636694 -0800
+@@ -24,8 +24,7 @@ along with GCC; see the file COPYING3.
+ #include "c-common.h"
+ #include "c-indentation.h"
+ #include "selftest.h"
+-
+-extern cpp_options *cpp_opts;
++#include "diagnostic.h"
+ 
+ /* Round up VIS_COLUMN to nearest tab stop. */
+ 
+@@ -294,7 +293,7 @@ should_warn_for_misleading_indentation (
+   expanded_location next_stmt_exploc = expand_location (next_stmt_loc);
+   expanded_location guard_exploc = expand_location (guard_loc);
+ 
+-  const unsigned int tab_width = cpp_opts->tabstop;
++  const unsigned int tab_width = global_dc->tabstop;
+ 
+   /* They must be in the same file.  */
+   if (next_stmt_exploc.file != body_exploc.file)
+diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
+--- a/gcc/c-family/c.opt        2021-12-24 20:23:42.816809230 -0800
++++ b/gcc/c-family/c.opt        2021-12-25 01:20:53.475636694 -0800
+@@ -1876,10 +1876,6 @@ Enum(strong_eval_order) String(some) Val
+ EnumValue
+ Enum(strong_eval_order) String(all) Value(2)
+ 
+-ftabstop=
+-C ObjC C++ ObjC++ Joined RejectNegative UInteger
+--ftabstop=<number>     Distance between tab stops for column reporting.
+-
+ ftemplate-backtrace-limit=
+ C++ ObjC++ Joined RejectNegative UInteger Var(template_backtrace_limit) Init(10)
+ Set the maximum number of template instantiation notes for a single warning or error.
+diff --git a/gcc/c-family/c-opts.c b/gcc/c-family/c-opts.c
+--- a/gcc/c-family/c-opts.c     2021-12-24 20:23:44.824774786 -0800
++++ b/gcc/c-family/c-opts.c     2021-12-25 01:20:53.475636694 -0800
+@@ -504,12 +504,6 @@ c_common_handle_option (size_t scode, co
+        cpp_opts->track_macro_expansion = 2;
+       break;
+ 
+-    case OPT_ftabstop_:
+-      /* It is documented that we silently ignore silly values.  */
+-      if (value >= 1 && value <= 100)
+-       cpp_opts->tabstop = value;
+-      break;
+-
+     case OPT_fexec_charset_:
+       cpp_opts->narrow_charset = arg;
+       break;
+diff --git a/gcc/common.opt b/gcc/common.opt
+--- a/gcc/common.opt    2021-12-24 20:23:42.480814993 -0800
++++ b/gcc/common.opt    2021-12-25 01:20:53.475636694 -0800
+@@ -1325,6 +1325,14 @@ Enum(diagnostic_url_rule) String(always)
+ EnumValue
+ Enum(diagnostic_url_rule) String(auto) Value(DIAGNOSTICS_URL_AUTO)
+ 
++fdiagnostics-column-unit=
++Common Joined RejectNegative Enum(diagnostics_column_unit)
++-fdiagnostics-column-unit=[display|byte]       Select whether column numbers are output as display columns (default) or raw bytes.
++
++fdiagnostics-column-origin=
++Common Joined RejectNegative UInteger
++-fdiagnostics-column-origin=<number>   Set the number of the first column.  The default is 1-based as per GNU style, but some utilities may expect 0-based, for example.
++
+ fdiagnostics-format=
+ Common Joined RejectNegative Enum(diagnostics_output_format)
+ -fdiagnostics-format=[text|json]       Select output format.
+@@ -1334,6 +1342,15 @@ SourceInclude
+ diagnostic.h
+ 
+ Enum
++Name(diagnostics_column_unit) Type(int)
++
++EnumValue
++Enum(diagnostics_column_unit) String(display) Value(DIAGNOSTICS_COLUMN_UNIT_DISPLAY)
++
++EnumValue
++Enum(diagnostics_column_unit) String(byte) Value(DIAGNOSTICS_COLUMN_UNIT_BYTE)
++
++Enum
+ Name(diagnostics_output_format) Type(int)
+ 
+ EnumValue
+@@ -1362,6 +1379,10 @@ fdiagnostics-path-format=
+ Common Joined RejectNegative Var(flag_diagnostics_path_format) Enum(diagnostic_path_format) Init(DPF_INLINE_EVENTS)
+ Specify how to print any control-flow path associated with a diagnostic.
+ 
++ftabstop=
++Common Joined RejectNegative UInteger
++-ftabstop=<number>      Distance between tab stops for column reporting.
++
+ Enum
+ Name(diagnostic_path_format) Type(int)
+ 
+diff --git a/gcc/diagnostic.c b/gcc/diagnostic.c
+--- a/gcc/diagnostic.c  2020-07-22 23:35:17.556386887 -0700
++++ b/gcc/diagnostic.c  2021-12-25 01:23:41.300841207 -0800
+@@ -38,6 +38,7 @@ along with GCC; see the file COPYING3.
+ #include "selftest.h"
+ #include "selftest-diagnostic.h"
+ #include "opts.h"
++#include "cpplib.h"
+ 
+ #ifdef HAVE_TERMIOS_H
+ # include <termios.h>
+@@ -219,6 +220,9 @@ diagnostic_initialize (diagnostic_contex
+   context->min_margin_width = 0;
+   context->show_ruler_p = false;
+   context->parseable_fixits_p = false;
++  context->column_unit = DIAGNOSTICS_COLUMN_UNIT_DISPLAY;
++  context->column_origin = 1;
++  context->tabstop = 8;
+   context->edit_context_ptr = NULL;
+   context->diagnostic_group_nesting_depth = 0;
+   context->diagnostic_group_emission_count = 0;
+@@ -353,8 +357,51 @@ diagnostic_get_color_for_kind (diagnosti
+   return diagnostic_kind_color[kind];
+ }
+ 
++/* Given an expanded_location, convert the column (which is in 1-based bytes)
++   to the requested units, without converting the origin.
++   Return -1 if the column is invalid (<= 0).  */
++
++static int
++convert_column_unit (enum diagnostics_column_unit column_unit,
++                    int tabstop,
++                    expanded_location s)
++{
++  if (s.column <= 0)
++    return -1;
++
++  switch (column_unit)
++    {
++    default:
++      gcc_unreachable ();
++
++    case DIAGNOSTICS_COLUMN_UNIT_DISPLAY:
++      {
++       cpp_char_column_policy policy (tabstop, cpp_wcwidth);
++       return location_compute_display_column (s, policy);
++      }
++
++    case DIAGNOSTICS_COLUMN_UNIT_BYTE:
++      return s.column;
++    }
++}
++
++/* Given an expanded_location, convert the column (which is in 1-based bytes)
++   to the requested units and origin.  Return -1 if the column is
++   invalid (<= 0).  */
++int
++diagnostic_converted_column (diagnostic_context *context, expanded_location s)
++{
++  int one_based_col
++    = convert_column_unit (context->column_unit, context->tabstop, s);
++  if (one_based_col <= 0)
++    return -1;
++  return one_based_col + (context->column_origin - 1);
++}
++
+ /* Return a formatted line and column ':%line:%column'.  Elided if
+-   zero.  The result is a statically allocated buffer.  */
++   line == 0 or col < 0.  (A column of 0 may be valid due to the
++   -fdiagnostics-column-origin option.)
++   The result is a statically allocated buffer.  */
+ 
+ static const char *
+ maybe_line_and_column (int line, int col)
+@@ -363,8 +410,9 @@ maybe_line_and_column (int line, int col
+ 
+   if (line)
+     {
+-      size_t l = snprintf (result, sizeof (result),
+-                          col ? ":%d:%d" : ":%d", line, col);
++      size_t l
++       = snprintf (result, sizeof (result),
++                   col >= 0 ? ":%d:%d" : ":%d", line, col);
+       gcc_checking_assert (l < sizeof (result));
+     }
+   else
+@@ -383,8 +431,14 @@ diagnostic_get_location_text (diagnostic
+   const char *locus_cs = colorize_start (pp_show_color (pp), "locus");
+   const char *locus_ce = colorize_stop (pp_show_color (pp));
+   const char *file = s.file ? s.file : progname;
+-  int line = strcmp (file, N_("<built-in>")) ? s.line : 0;
+-  int col = context->show_column ? s.column : 0;
++  int line = 0;
++  int col = -1;
++  if (strcmp (file, N_("<built-in>")))
++    {
++      line = s.line;
++      if (context->show_column)
++       col = diagnostic_converted_column (context, s);
++    }
+ 
+   const char *line_col = maybe_line_and_column (line, col);
+   return build_message_string ("%s%s%s:%s", locus_cs, file,
+@@ -650,14 +704,20 @@ diagnostic_report_current_module (diagno
+       if (! MAIN_FILE_P (map))
+        {
+          bool first = true;
++         expanded_location s = {};
+          do
+            {
+              where = linemap_included_from (map);
+              map = linemap_included_from_linemap (line_table, map);
+-             const char *line_col
+-               = maybe_line_and_column (SOURCE_LINE (map, where),
+-                                        first && context->show_column
+-                                        ? SOURCE_COLUMN (map, where) : 0);
++             s.file = LINEMAP_FILE (map);
++             s.line = SOURCE_LINE (map, where);
++             int col = -1;
++             if (first && context->show_column)
++               {
++                 s.column = SOURCE_COLUMN (map, where);
++                 col = diagnostic_converted_column (context, s);
++               }
++             const char *line_col = maybe_line_and_column (s.line, col);
+              static const char *const msgs[] =
+                {
+                 N_("In file included from"),
+@@ -666,7 +726,7 @@ diagnostic_report_current_module (diagno
+              unsigned index = !first;
+              pp_verbatim (context->printer, "%s%s %r%s%s%R",
+                           first ? "" : ",\n", _(msgs[index]),
+-                          "locus", LINEMAP_FILE (map), line_col);
++                          "locus", s.file, line_col);
+              first = false;
+            }
+          while (! MAIN_FILE_P (map));
+@@ -2042,10 +2102,15 @@ test_print_parseable_fixits_replace ()
+ static void
+ assert_location_text (const char *expected_loc_text,
+                      const char *filename, int line, int column,
+-                     bool show_column)
++                     bool show_column,
++                     int origin = 1,
++                     enum diagnostics_column_unit column_unit
++                       = DIAGNOSTICS_COLUMN_UNIT_BYTE)
+ {
+   test_diagnostic_context dc;
+   dc.show_column = show_column;
++  dc.column_unit = column_unit;
++  dc.column_origin = origin;
+ 
+   expanded_location xloc;
+   xloc.file = filename;
+@@ -2069,7 +2134,10 @@ test_diagnostic_get_location_text ()
+   assert_location_text ("PROGNAME:", NULL, 0, 0, true);
+   assert_location_text ("<built-in>:", "<built-in>", 42, 10, true);
+   assert_location_text ("foo.c:42:10:", "foo.c", 42, 10, true);
+-  assert_location_text ("foo.c:42:", "foo.c", 42, 0, true);
++  assert_location_text ("foo.c:42:9:", "foo.c", 42, 10, true, 0);
++  assert_location_text ("foo.c:42:1010:", "foo.c", 42, 10, true, 1001);
++  for (int origin = 0; origin != 2; ++origin)
++    assert_location_text ("foo.c:42:", "foo.c", 42, 0, true, origin);
+   assert_location_text ("foo.c:", "foo.c", 0, 10, true);
+   assert_location_text ("foo.c:42:", "foo.c", 42, 10, false);
+   assert_location_text ("foo.c:", "foo.c", 0, 10, false);
+@@ -2077,6 +2145,41 @@ test_diagnostic_get_location_text ()
+   maybe_line_and_column (INT_MAX, INT_MAX);
+   maybe_line_and_column (INT_MIN, INT_MIN);
+ 
++  {
++    /* In order to test display columns vs byte columns, we need to create a
++       file for location_get_source_line() to read.  */
++
++    const char *const content = "smile \xf0\x9f\x98\x82\n";
++    const int line_bytes = strlen (content) - 1;
++    const int def_tabstop = 8;
++    const int display_width = cpp_display_width (content, line_bytes,
++                                                def_tabstop);
++    ASSERT_EQ (line_bytes - 2, display_width);
++    temp_source_file tmp (SELFTEST_LOCATION, ".c", content);
++    const char *const fname = tmp.get_filename ();
++    const int buf_len = strlen (fname) + 16;
++    char *const expected = XNEWVEC (char, buf_len);
++
++    snprintf (expected, buf_len, "%s:1:%d:", fname, line_bytes);
++    assert_location_text (expected, fname, 1, line_bytes, true,
++                         1, DIAGNOSTICS_COLUMN_UNIT_BYTE);
++
++    snprintf (expected, buf_len, "%s:1:%d:", fname, line_bytes - 1);
++    assert_location_text (expected, fname, 1, line_bytes, true,
++                         0, DIAGNOSTICS_COLUMN_UNIT_BYTE);
++
++    snprintf (expected, buf_len, "%s:1:%d:", fname, display_width);
++    assert_location_text (expected, fname, 1, line_bytes, true,
++                         1, DIAGNOSTICS_COLUMN_UNIT_DISPLAY);
++
++    snprintf (expected, buf_len, "%s:1:%d:", fname, display_width - 1);
++    assert_location_text (expected, fname, 1, line_bytes, true,
++                         0, DIAGNOSTICS_COLUMN_UNIT_DISPLAY);
++
++    XDELETEVEC (expected);
++  }
++
++
+   progname = old_progname;
+ }
+ 
+diff --git a/gcc/diagnostic-format-json.cc b/gcc/diagnostic-format-json.cc
+--- a/gcc/diagnostic-format-json.cc     2020-07-22 23:35:17.556386887 -0700
++++ b/gcc/diagnostic-format-json.cc     2021-12-25 01:20:53.475636694 -0800
+@@ -23,6 +23,7 @@ along with GCC; see the file COPYING3.
+ #include "system.h"
+ #include "coretypes.h"
+ #include "diagnostic.h"
++#include "selftest-diagnostic.h"
+ #include "diagnostic-metadata.h"
+ #include "json.h"
+ #include "selftest.h"
+@@ -43,21 +44,43 @@ static json::array *cur_children_array;
+ /* Generate a JSON object for LOC.  */
+ 
+ json::value *
+-json_from_expanded_location (location_t loc)
++json_from_expanded_location (diagnostic_context *context, location_t loc)
+ {
+   expanded_location exploc = expand_location (loc);
+   json::object *result = new json::object ();
+   if (exploc.file)
+     result->set ("file", new json::string (exploc.file));
+   result->set ("line", new json::integer_number (exploc.line));
+-  result->set ("column", new json::integer_number (exploc.column));
++
++  const enum diagnostics_column_unit orig_unit = context->column_unit;
++  struct
++  {
++    const char *name;
++    enum diagnostics_column_unit unit;
++  } column_fields[] = {
++    {"display-column", DIAGNOSTICS_COLUMN_UNIT_DISPLAY},
++    {"byte-column", DIAGNOSTICS_COLUMN_UNIT_BYTE}
++  };
++  int the_column = INT_MIN;
++  for (int i = 0; i != sizeof column_fields / sizeof (*column_fields); ++i)
++    {
++      context->column_unit = column_fields[i].unit;
++      const int col = diagnostic_converted_column (context, exploc);
++      result->set (column_fields[i].name, new json::integer_number (col));
++      if (column_fields[i].unit == orig_unit)
++       the_column = col;
++    }
++  gcc_assert (the_column != INT_MIN);
++  result->set ("column", new json::integer_number (the_column));
++  context->column_unit = orig_unit;
+   return result;
+ }
+ 
+ /* Generate a JSON object for LOC_RANGE.  */
+ 
+ static json::object *
+-json_from_location_range (const location_range *loc_range, unsigned range_idx)
++json_from_location_range (diagnostic_context *context,
++                         const location_range *loc_range, unsigned range_idx)
+ {
+   location_t caret_loc = get_pure_location (loc_range->m_loc);
+ 
+@@ -68,13 +91,13 @@ json_from_location_range (const location
+   location_t finish_loc = get_finish (loc_range->m_loc);
+ 
+   json::object *result = new json::object ();
+-  result->set ("caret", json_from_expanded_location (caret_loc));
++  result->set ("caret", json_from_expanded_location (context, caret_loc));
+   if (start_loc != caret_loc
+       && start_loc != UNKNOWN_LOCATION)
+-    result->set ("start", json_from_expanded_location (start_loc));
++    result->set ("start", json_from_expanded_location (context, start_loc));
+   if (finish_loc != caret_loc
+       && finish_loc != UNKNOWN_LOCATION)
+-    result->set ("finish", json_from_expanded_location (finish_loc));
++    result->set ("finish", json_from_expanded_location (context, finish_loc));
+ 
+   if (loc_range->m_label)
+     {
+@@ -91,14 +114,14 @@ json_from_location_range (const location
+ /* Generate a JSON object for HINT.  */
+ 
+ static json::object *
+-json_from_fixit_hint (const fixit_hint *hint)
++json_from_fixit_hint (diagnostic_context *context, const fixit_hint *hint)
+ {
+   json::object *fixit_obj = new json::object ();
+ 
+   location_t start_loc = hint->get_start_loc ();
+-  fixit_obj->set ("start", json_from_expanded_location (start_loc));
++  fixit_obj->set ("start", json_from_expanded_location (context, start_loc));
+   location_t next_loc = hint->get_next_loc ();
+-  fixit_obj->set ("next", json_from_expanded_location (next_loc));
++  fixit_obj->set ("next", json_from_expanded_location (context, next_loc));
+   fixit_obj->set ("string", new json::string (hint->get_string ()));
+ 
+   return fixit_obj;
+@@ -190,11 +213,13 @@ json_end_diagnostic (diagnostic_context
+   else
+     {
+       /* Otherwise, make diag_obj be the top-level object within the group;
+-        add a "children" array.  */
++        add a "children" array and record the column origin.  */
+       toplevel_array->append (diag_obj);
+       cur_group = diag_obj;
+       cur_children_array = new json::array ();
+       diag_obj->set ("children", cur_children_array);
++      diag_obj->set ("column-origin",
++                    new json::integer_number (context->column_origin));
+     }
+ 
+   const rich_location *richloc = diagnostic->richloc;
+@@ -205,7 +230,7 @@ json_end_diagnostic (diagnostic_context
+   for (unsigned int i = 0; i < richloc->get_num_locations (); i++)
+     {
+       const location_range *loc_range = richloc->get_range (i);
+-      json::object *loc_obj = json_from_location_range (loc_range, i);
++      json::object *loc_obj = json_from_location_range (context, loc_range, i);
+       if (loc_obj)
+        loc_array->append (loc_obj);
+     }
+@@ -217,7 +242,7 @@ json_end_diagnostic (diagnostic_context
+       for (unsigned int i = 0; i < richloc->get_num_fixit_hints (); i++)
+        {
+          const fixit_hint *hint = richloc->get_fixit_hint (i);
+-         json::object *fixit_obj = json_from_fixit_hint (hint);
++         json::object *fixit_obj = json_from_fixit_hint (context, hint);
+          fixit_array->append (fixit_obj);
+        }
+     }
+@@ -320,7 +345,8 @@ namespace selftest {
+ static void
+ test_unknown_location ()
+ {
+-  delete json_from_expanded_location (UNKNOWN_LOCATION);
++  test_diagnostic_context dc;
++  delete json_from_expanded_location (&dc, UNKNOWN_LOCATION);
+ }
+ 
+ /* Verify that we gracefully handle attempts to serialize bad
+@@ -338,7 +364,8 @@ test_bad_endpoints ()
+   loc_range.m_range_display_kind = SHOW_RANGE_WITH_CARET;
+   loc_range.m_label = NULL;
+ 
+-  json::object *obj = json_from_location_range (&loc_range, 0);
++  test_diagnostic_context dc;
++  json::object *obj = json_from_location_range (&dc, &loc_range, 0);
+   /* We should have a "caret" value, but no "start" or "finish" values.  */
+   ASSERT_TRUE (obj != NULL);
+   ASSERT_TRUE (obj->get ("caret") != NULL);
+diff --git a/gcc/diagnostic.h b/gcc/diagnostic.h
+--- a/gcc/diagnostic.h  2020-07-22 23:35:17.556386887 -0700
++++ b/gcc/diagnostic.h  2021-12-25 01:20:53.479636627 -0800
+@@ -24,6 +24,20 @@ along with GCC; see the file COPYING3.
+ #include "pretty-print.h"
+ #include "diagnostic-core.h"
+ 
++/* An enum for controlling what units to use for the column number
++   when diagnostics are output, used by the -fdiagnostics-column-unit option.
++   Tabs will be expanded or not according to the value of -ftabstop.  The origin
++   (default 1) is controlled by -fdiagnostics-column-origin.  */
++
++enum diagnostics_column_unit
++{
++  /* The default from GCC 11 onwards: display columns.  */
++  DIAGNOSTICS_COLUMN_UNIT_DISPLAY,
++
++  /* The behavior in GCC 10 and earlier: simple bytes.  */
++  DIAGNOSTICS_COLUMN_UNIT_BYTE
++};
++
+ /* Enum for overriding the standard output format.  */
+ 
+ enum diagnostics_output_format
+@@ -280,6 +294,15 @@ struct diagnostic_context
+      rest of the diagnostic.  */
+   bool parseable_fixits_p;
+ 
++  /* What units to use when outputting the column number.  */
++  enum diagnostics_column_unit column_unit;
++
++  /* The origin for the column number (1-based or 0-based typically).  */
++  int column_origin;
++
++  /* The size of the tabstop for tab expansion.  */
++  int tabstop;
++
+   /* If non-NULL, an edit_context to which fix-it hints should be
+      applied, for generating patches.  */
+   edit_context *edit_context_ptr;
+@@ -458,6 +481,8 @@ diagnostic_same_line (const diagnostic_c
+ }
+ 
+ extern const char *diagnostic_get_color_for_kind (diagnostic_t kind);
++extern int diagnostic_converted_column (diagnostic_context *context,
++                                       expanded_location s);
+ 
+ /* Pure text formatting support functions.  */
+ extern char *file_name_as_prefix (diagnostic_context *, const char *);
+@@ -470,6 +495,7 @@ extern void diagnostic_output_format_ini
+ /* Compute the number of digits in the decimal representation of an integer.  */
+ extern int num_digits (int);
+ 
+-extern json::value *json_from_expanded_location (location_t loc);
++extern json::value *json_from_expanded_location (diagnostic_context *context,
++                                                location_t loc);
+ 
+ #endif /* ! GCC_DIAGNOSTIC_H */
+diff --git a/gcc/diagnostic-show-locus.c b/gcc/diagnostic-show-locus.c
+--- a/gcc/diagnostic-show-locus.c       2020-07-22 23:35:17.556386887 -0700
++++ b/gcc/diagnostic-show-locus.c       2021-12-25 01:20:53.479636627 -0800
+@@ -175,9 +175,10 @@ enum column_unit {
+ class exploc_with_display_col : public expanded_location
+ {
+  public:
+-  exploc_with_display_col (const expanded_location &exploc)
++  exploc_with_display_col (const expanded_location &exploc, int tabstop)
+     : expanded_location (exploc),
+-      m_display_col (location_compute_display_column (exploc)) {}
++      m_display_col (location_compute_display_column (exploc, tabstop))
++  {}
+ 
+   int m_display_col;
+ };
+@@ -189,11 +190,11 @@ class exploc_with_display_col : public e
+ class layout_point
+ {
+  public:
+-  layout_point (const expanded_location &exploc)
++  layout_point (const exploc_with_display_col &exploc)
+     : m_line (exploc.line)
+   {
+     m_columns[CU_BYTES] = exploc.column;
+-    m_columns[CU_DISPLAY_COLS] = location_compute_display_column (exploc);
++    m_columns[CU_DISPLAY_COLS] = exploc.m_display_col;
+   }
+ 
+   linenum_type m_line;
+@@ -205,10 +206,10 @@ class layout_point
+ class layout_range
+ {
+  public:
+-  layout_range (const expanded_location *start_exploc,
+-               const expanded_location *finish_exploc,
++  layout_range (const exploc_with_display_col &start_exploc,
++               const exploc_with_display_col &finish_exploc,
+                enum range_display_kind range_display_kind,
+-               const expanded_location *caret_exploc,
++               const exploc_with_display_col &caret_exploc,
+                unsigned original_idx,
+                const range_label *label);
+ 
+@@ -226,22 +227,18 @@ class layout_range
+ 
+ /* A struct for use by layout::print_source_line for telling
+    layout::print_annotation_line the extents of the source line that
+-   it printed, so that underlines can be clipped appropriately.  */
++   it printed, so that underlines can be clipped appropriately.  Units
++   are 1-based display columns.  */
+ 
+ struct line_bounds
+ {
+-  int m_first_non_ws;
+-  int m_last_non_ws;
++  int m_first_non_ws_disp_col;
++  int m_last_non_ws_disp_col;
+ 
+-  void convert_to_display_cols (char_span line)
++  line_bounds ()
+   {
+-    m_first_non_ws = cpp_byte_column_to_display_column (line.get_buffer (),
+-                                                       line.length (),
+-                                                       m_first_non_ws);
+-
+-    m_last_non_ws = cpp_byte_column_to_display_column (line.get_buffer (),
+-                                                      line.length (),
+-                                                      m_last_non_ws);
++    m_first_non_ws_disp_col = INT_MAX;
++    m_last_non_ws_disp_col = 0;
+   }
+ };
+ 
+@@ -351,8 +348,8 @@ class layout
+  private:
+   bool will_show_line_p (linenum_type row) const;
+   void print_leading_fixits (linenum_type row);
+-  void print_source_line (linenum_type row, const char *line, int line_bytes,
+-                         line_bounds *lbounds_out);
++  line_bounds print_source_line (linenum_type row, const char *line,
++                                int line_bytes);
+   bool should_print_annotation_line_p (linenum_type row) const;
+   void start_annotation_line (char margin_char = ' ') const;
+   void print_annotation_line (linenum_type row, const line_bounds lbounds);
+@@ -513,16 +510,16 @@ colorizer::get_color_by_name (const char
+    Initialize various layout_point fields from expanded_location
+    equivalents; we've already filtered on file.  */
+ 
+-layout_range::layout_range (const expanded_location *start_exploc,
+-                           const expanded_location *finish_exploc,
++layout_range::layout_range (const exploc_with_display_col &start_exploc,
++                           const exploc_with_display_col &finish_exploc,
+                            enum range_display_kind range_display_kind,
+-                           const expanded_location *caret_exploc,
++                           const exploc_with_display_col &caret_exploc,
+                            unsigned original_idx,
+                            const range_label *label)
+-: m_start (*start_exploc),
+-  m_finish (*finish_exploc),
++: m_start (start_exploc),
++  m_finish (finish_exploc),
+   m_range_display_kind (range_display_kind),
+-  m_caret (*caret_exploc),
++  m_caret (caret_exploc),
+   m_original_idx (original_idx),
+   m_label (label)
+ {
+@@ -646,6 +643,9 @@ layout_range::intersects_line_p (linenum
+ 
+ #if CHECKING_P
+ 
++/* Default for when we don't care what the tab expansion is set to.  */
++static const int def_tabstop = 8;
++
+ /* Create some expanded locations for testing layout_range.  The filename
+    member of the explocs is set to the empty string.  This member will only be
+    inspected by the calls to location_compute_display_column() made from the
+@@ -662,8 +662,11 @@ make_range (int start_line, int start_co
+     = {"", start_line, start_col, NULL, false};
+   const expanded_location finish_exploc
+     = {"", end_line, end_col, NULL, false};
+-  return layout_range (&start_exploc, &finish_exploc, SHOW_RANGE_WITHOUT_CARET,
+-                      &start_exploc, 0, NULL);
++  return layout_range (exploc_with_display_col (start_exploc, def_tabstop),
++                      exploc_with_display_col (finish_exploc, def_tabstop),
++                      SHOW_RANGE_WITHOUT_CARET,
++                      exploc_with_display_col (start_exploc, def_tabstop),
++                      0, NULL);
+ }
+ 
+ /* Selftests for layout_range::contains_point and
+@@ -964,7 +967,7 @@ layout::layout (diagnostic_context * con
+ : m_context (context),
+   m_pp (context->printer),
+   m_primary_loc (richloc->get_range (0)->m_loc),
+-  m_exploc (richloc->get_expanded_location (0)),
++  m_exploc (richloc->get_expanded_location (0), context->tabstop),
+   m_colorizer (context, diagnostic_kind),
+   m_colorize_source_p (context->colorize_source_p),
+   m_show_labels_p (context->show_labels_p),
+@@ -1060,7 +1063,10 @@ layout::maybe_add_location_range (const
+ 
+   /* Everything is now known to be in the correct source file,
+      but it may require further sanitization.  */
+-  layout_range ri (&start, &finish, loc_range->m_range_display_kind, &caret,
++  layout_range ri (exploc_with_display_col (start, m_context->tabstop),
++                  exploc_with_display_col (finish, m_context->tabstop),
++                  loc_range->m_range_display_kind,
++                  exploc_with_display_col (caret, m_context->tabstop),
+                   original_idx, loc_range->m_label);
+ 
+   /* If we have a range that finishes before it starts (perhaps
+@@ -1394,7 +1400,7 @@ layout::calculate_x_offset_display ()
+     = get_line_bytes_without_trailing_whitespace (line.get_buffer (),
+                                                  line.length ());
+   int eol_display_column
+-    = cpp_display_width (line.get_buffer (), line_bytes);
++    = cpp_display_width (line.get_buffer (), line_bytes, m_context->tabstop);
+   if (caret_display_column > eol_display_column
+       || !caret_display_column)
+     {
+@@ -1445,16 +1451,13 @@ layout::calculate_x_offset_display ()
+ }
+ 
+ /* Print line ROW of source code, potentially colorized at any ranges, and
+-   populate *LBOUNDS_OUT.
+-   LINE is the source line (not necessarily 0-terminated) and LINE_BYTES
+-   is its length in bytes.
+-   This function deals only with byte offsets, not display columns, so
+-   m_x_offset_display must be converted from display to byte units.  In
+-   particular, LINE_BYTES and LBOUNDS_OUT are in bytes.  */
++   return the line bounds.  LINE is the source line (not necessarily
++   0-terminated) and LINE_BYTES is its length in bytes.  In order to handle both
++   colorization and tab expansion, this function tracks the line position in
++   both byte and display column units.  */
+ 
+-void
+-layout::print_source_line (linenum_type row, const char *line, int line_bytes,
+-                          line_bounds *lbounds_out)
++line_bounds
++layout::print_source_line (linenum_type row, const char *line, int line_bytes)
+ {
+   m_colorizer.set_normal_text ();
+ 
+@@ -1469,30 +1472,29 @@ layout::print_source_line (linenum_type
+   else
+     pp_space (m_pp);
+ 
+-  /* We will stop printing the source line at any trailing whitespace, and start
+-     printing it as per m_x_offset_display.  */
++  /* We will stop printing the source line at any trailing whitespace.  */
+   line_bytes = get_line_bytes_without_trailing_whitespace (line,
+                                                           line_bytes);
+-  int x_offset_bytes = 0;
+-  if (m_x_offset_display)
+-    {
+-      x_offset_bytes = cpp_display_column_to_byte_column (line, line_bytes,
+-                                                         m_x_offset_display);
+-      /* In case the leading portion of the line that will be skipped over ends
+-        with a character with wcwidth > 1, then it is possible we skipped too
+-        much, so account for that by padding with spaces.  */
+-      const int overage
+-       = cpp_byte_column_to_display_column (line, line_bytes, x_offset_bytes)
+-       - m_x_offset_display;
+-      for (int column = 0; column < overage; ++column)
+-       pp_space (m_pp);
+-      line += x_offset_bytes;
+-    }
+ 
+-  /* Print the line.  */
+-  int first_non_ws = INT_MAX;
+-  int last_non_ws = 0;
+-  for (int col_byte = 1 + x_offset_bytes; col_byte <= line_bytes; col_byte++)
++  /* This object helps to keep track of which display column we are at, which is
++     necessary for computing the line bounds in display units, for doing
++     tab expansion, and for implementing m_x_offset_display.  */
++  cpp_display_width_computation dw (line, line_bytes, m_context->tabstop);
++
++  /* Skip the first m_x_offset_display display columns.  In case the leading
++     portion that will be skipped ends with a character with wcwidth > 1, then
++     it is possible we skipped too much, so account for that by padding with
++     spaces.  Note that this does the right thing too in case a tab was the last
++     character to be skipped over; the tab is effectively replaced by the
++     correct number of trailing spaces needed to offset by the desired number of
++     display columns.  */
++  for (int skipped_display_cols = dw.advance_display_cols (m_x_offset_display);
++       skipped_display_cols > m_x_offset_display; --skipped_display_cols)
++    pp_space (m_pp);
++
++  /* Print the line and compute the line_bounds.  */
++  line_bounds lbounds;
++  while (!dw.done ())
+     {
+       /* Assuming colorization is enabled for the caret and underline
+         characters, we may also colorize the associated characters
+@@ -1510,7 +1512,8 @@ layout::print_source_line (linenum_type
+        {
+          bool in_range_p;
+          point_state state;
+-         in_range_p = get_state_at_point (row, col_byte,
++         const int start_byte_col = dw.bytes_processed () + 1;
++         in_range_p = get_state_at_point (row, start_byte_col,
+                                           0, INT_MAX,
+                                           CU_BYTES,
+                                           &state);
+@@ -1519,22 +1522,44 @@ layout::print_source_line (linenum_type
+          else
+            m_colorizer.set_normal_text ();
+        }
+-      char c = *line;
+-      if (c == '\0' || c == '\t' || c == '\r')
+-       c = ' ';
+-      if (c != ' ')
++
++      /* Get the display width of the next character to be output, expanding
++        tabs and replacing some control bytes with spaces as necessary.  */
++      const char *c = dw.next_byte ();
++      const int start_disp_col = dw.display_cols_processed () + 1;
++      const int this_display_width = dw.process_next_codepoint ();
++      if (*c == '\t')
++       {
++         /* The returned display width is the number of spaces into which the
++            tab should be expanded.  */
++         for (int i = 0; i != this_display_width; ++i)
++           pp_space (m_pp);
++         continue;
++       }
++      if (*c == '\0' || *c == '\r')
+        {
+-         last_non_ws = col_byte;
+-         if (first_non_ws == INT_MAX)
+-           first_non_ws = col_byte;
++         /* cpp_wcwidth() promises to return 1 for all control bytes, and we
++            want to output these as a single space too, so this case is
++            actually the same as the '\t' case.  */
++         gcc_assert (this_display_width == 1);
++         pp_space (m_pp);
++         continue;
+        }
+-      pp_character (m_pp, c);
+-      line++;
++
++      /* We have a (possibly multibyte) character to output; update the line
++        bounds if it is not whitespace.  */
++      if (*c != ' ')
++       {
++         lbounds.m_last_non_ws_disp_col = dw.display_cols_processed ();
++         if (lbounds.m_first_non_ws_disp_col == INT_MAX)
++           lbounds.m_first_non_ws_disp_col = start_disp_col;
++       }
++
++      /* Output the character.  */
++      while (c != dw.next_byte ()) pp_character (m_pp, *c++);
+     }
+   print_newline ();
+-
+-  lbounds_out->m_first_non_ws = first_non_ws;
+-  lbounds_out->m_last_non_ws = last_non_ws;
++  return lbounds;
+ }
+ 
+ /* Determine if we should print an annotation line for ROW.
+@@ -1576,14 +1601,13 @@ layout::start_annotation_line (char marg
+ }
+ 
+ /* Print a line consisting of the caret/underlines for the given
+-   source line.  This function works with display columns, rather than byte
+-   counts; in particular, LBOUNDS should be in display column units.  */
++   source line.  */
+ 
+ void
+ layout::print_annotation_line (linenum_type row, const line_bounds lbounds)
+ {
+   int x_bound = get_x_bound_for_row (row, m_exploc.m_display_col,
+-                                    lbounds.m_last_non_ws);
++                                    lbounds.m_last_non_ws_disp_col);
+ 
+   start_annotation_line ();
+   pp_space (m_pp);
+@@ -1593,8 +1617,8 @@ layout::print_annotation_line (linenum_t
+       bool in_range_p;
+       point_state state;
+       in_range_p = get_state_at_point (row, column,
+-                                      lbounds.m_first_non_ws,
+-                                      lbounds.m_last_non_ws,
++                                      lbounds.m_first_non_ws_disp_col,
++                                      lbounds.m_last_non_ws_disp_col,
+                                       CU_DISPLAY_COLS,
+                                       &state);
+       if (in_range_p)
+@@ -1631,12 +1655,14 @@ layout::print_annotation_line (linenum_t
+ class line_label
+ {
+ public:
+-  line_label (int state_idx, int column, label_text text)
++  line_label (diagnostic_context *context, int state_idx, int column,
++             label_text text)
+   : m_state_idx (state_idx), m_column (column),
+     m_text (text), m_label_line (0), m_has_vbar (true)
+   {
+     const int bytes = strlen (text.m_buffer);
+-    m_display_width = cpp_display_width (text.m_buffer, bytes);
++    m_display_width
++      = cpp_display_width (text.m_buffer, bytes, context->tabstop);
+   }
+ 
+   /* Sorting is primarily by column, then by state index.  */
+@@ -1696,7 +1722,7 @@ layout::print_any_labels (linenum_type r
+        if (text.m_buffer == NULL)
+          continue;
+ 
+-       labels.safe_push (line_label (i, disp_col, text));
++       labels.safe_push (line_label (m_context, i, disp_col, text));
+       }
+   }
+ 
+@@ -1976,7 +2002,8 @@ public:
+ 
+ /* Get the range of bytes or display columns that HINT would affect.  */
+ static column_range
+-get_affected_range (const fixit_hint *hint, enum column_unit col_unit)
++get_affected_range (diagnostic_context *context,
++                   const fixit_hint *hint, enum column_unit col_unit)
+ {
+   expanded_location exploc_start = expand_location (hint->get_start_loc ());
+   expanded_location exploc_finish = expand_location (hint->get_next_loc ());
+@@ -1986,11 +2013,13 @@ get_affected_range (const fixit_hint *hi
+   int finish_column;
+   if (col_unit == CU_DISPLAY_COLS)
+     {
+-      start_column = location_compute_display_column (exploc_start);
++      start_column
++       = location_compute_display_column (exploc_start, context->tabstop);
+       if (hint->insertion_p ())
+        finish_column = start_column - 1;
+       else
+-       finish_column = location_compute_display_column (exploc_finish);
++       finish_column
++         = location_compute_display_column (exploc_finish, context->tabstop);
+     }
+   else
+     {
+@@ -2003,12 +2032,12 @@ get_affected_range (const fixit_hint *hi
+ /* Get the range of display columns that would be printed for HINT.  */
+ 
+ static column_range
+-get_printed_columns (const fixit_hint *hint)
++get_printed_columns (diagnostic_context *context, const fixit_hint *hint)
+ {
+   expanded_location exploc = expand_location (hint->get_start_loc ());
+-  int start_column = location_compute_display_column (exploc);
+-  int hint_width = cpp_display_width (hint->get_string (),
+-                                     hint->get_length ());
++  int start_column = location_compute_display_column (exploc, context->tabstop);
++  int hint_width = cpp_display_width (hint->get_string (), hint->get_length (),
++                                     context->tabstop);
+   int final_hint_column = start_column + hint_width - 1;
+   if (hint->insertion_p ())
+     {
+@@ -2018,7 +2047,8 @@ get_printed_columns (const fixit_hint *h
+     {
+       exploc = expand_location (hint->get_next_loc ());
+       --exploc.column;
+-      int finish_column = location_compute_display_column (exploc);
++      int finish_column
++       = location_compute_display_column (exploc, context->tabstop);
+       return column_range (start_column,
+                           MAX (finish_column, final_hint_column));
+     }
+@@ -2035,12 +2065,14 @@ public:
+   correction (column_range affected_bytes,
+              column_range affected_columns,
+              column_range printed_columns,
+-             const char *new_text, size_t new_text_len)
++             const char *new_text, size_t new_text_len,
++             int tabstop)
+   : m_affected_bytes (affected_bytes),
+     m_affected_columns (affected_columns),
+     m_printed_columns (printed_columns),
+     m_text (xstrdup (new_text)),
+     m_byte_length (new_text_len),
++    m_tabstop (tabstop),
+     m_alloc_sz (new_text_len + 1)
+   {
+     compute_display_cols ();
+@@ -2058,7 +2090,7 @@ public:
+ 
+   void compute_display_cols ()
+   {
+-    m_display_cols = cpp_display_width (m_text, m_byte_length);
++    m_display_cols = cpp_display_width (m_text, m_byte_length, m_tabstop);
+   }
+ 
+   void overwrite (int dst_offset, const char_span &src_span)
+@@ -2086,6 +2118,7 @@ public:
+   char *m_text;
+   size_t m_byte_length; /* Not including null-terminator.  */
+   int m_display_cols;
++  int m_tabstop;
+   size_t m_alloc_sz;
+ };
+ 
+@@ -2121,13 +2154,15 @@ correction::ensure_terminated ()
+ class line_corrections
+ {
+ public:
+-  line_corrections (const char *filename, linenum_type row)
+-  : m_filename (filename), m_row (row)
++  line_corrections (diagnostic_context *context, const char *filename,
++                   linenum_type row)
++    : m_context (context), m_filename (filename), m_row (row)
+   {}
+   ~line_corrections ();
+ 
+   void add_hint (const fixit_hint *hint);
+ 
++  diagnostic_context *m_context;
+   const char *m_filename;
+   linenum_type m_row;
+   auto_vec <correction *> m_corrections;
+@@ -2173,9 +2208,10 @@ source_line::source_line (const char *fi
+ void
+ line_corrections::add_hint (const fixit_hint *hint)
+ {
+-  column_range affected_bytes = get_affected_range (hint, CU_BYTES);
+-  column_range affected_columns = get_affected_range (hint, CU_DISPLAY_COLS);
+-  column_range printed_columns = get_printed_columns (hint);
++  column_range affected_bytes = get_affected_range (m_context, hint, CU_BYTES);
++  column_range affected_columns = get_affected_range (m_context, hint,
++                                                     CU_DISPLAY_COLS);
++  column_range printed_columns = get_printed_columns (m_context, hint);
+ 
+   /* Potentially consolidate.  */
+   if (!m_corrections.is_empty ())
+@@ -2243,7 +2279,8 @@ line_corrections::add_hint (const fixit_
+                                           affected_columns,
+                                           printed_columns,
+                                           hint->get_string (),
+-                                          hint->get_length ()));
++                                          hint->get_length (),
++                                          m_context->tabstop));
+ }
+ 
+ /* If there are any fixit hints on source line ROW, print them.
+@@ -2257,7 +2294,7 @@ layout::print_trailing_fixits (linenum_t
+ {
+   /* Build a list of correction instances for the line,
+      potentially consolidating hints (for the sake of readability).  */
+-  line_corrections corrections (m_exploc.file, row);
++  line_corrections corrections (m_context, m_exploc.file, row);
+   for (unsigned int i = 0; i < m_fixit_hints.length (); i++)
+     {
+       const fixit_hint *hint = m_fixit_hints[i];
+@@ -2499,15 +2536,11 @@ layout::print_line (linenum_type row)
+   if (!line)
+     return;
+ 
+-  line_bounds lbounds;
+   print_leading_fixits (row);
+-  print_source_line (row, line.get_buffer (), line.length (), &lbounds);
++  const line_bounds lbounds
++    = print_source_line (row, line.get_buffer (), line.length ());
+   if (should_print_annotation_line_p (row))
+-    {
+-      if (lbounds.m_first_non_ws != INT_MAX)
+-       lbounds.convert_to_display_cols (line);
+-      print_annotation_line (row, lbounds);
+-    }
++    print_annotation_line (row, lbounds);
+   if (m_show_labels_p)
+     print_any_labels (row);
+   print_trailing_fixits (row);
+@@ -2670,9 +2703,11 @@ test_layout_x_offset_display_utf8 (const
+ 
+   char_span lspan = location_get_source_line (tmp.get_filename (), 1);
+   ASSERT_EQ (line_display_cols,
+-            cpp_display_width (lspan.get_buffer (), lspan.length ()));
++            cpp_display_width (lspan.get_buffer (), lspan.length (),
++                               def_tabstop));
+   ASSERT_EQ (line_display_cols,
+-            location_compute_display_column (expand_location (line_end)));
++            location_compute_display_column (expand_location (line_end),
++                                             def_tabstop));
+   ASSERT_EQ (0, memcmp (lspan.get_buffer () + (emoji_col - 1),
+                        "\xf0\x9f\x98\x82\xf0\x9f\x98\x82", 8));
+ 
+@@ -2774,6 +2809,111 @@ test_layout_x_offset_display_utf8 (const
+ 
+ }
+ 
++static void
++test_layout_x_offset_display_tab (const line_table_case &case_)
++{
++  const char *content
++    = "This line is very long, so that we can use it to test the logic for "
++      "clipping long lines.  Also this: `\t' is a tab that occupies 1 byte and "
++      "a variable number of display columns, starting at column #103.\n";
++
++  /* Number of bytes in the line, subtracting one to remove the newline.  */
++  const int line_bytes = strlen (content) - 1;
++
++ /* The column where the tab begins.  Byte or display is the same as there are
++    no multibyte characters earlier on the line.  */
++  const int tab_col = 103;
++
++  /* Effective extra size of the tab beyond what a single space would have taken
++     up, indexed by tabstop.  */
++  static const int num_tabstops = 11;
++  int extra_width[num_tabstops];
++  for (int tabstop = 1; tabstop != num_tabstops; ++tabstop)
++    {
++      const int this_tab_size = tabstop - (tab_col - 1) % tabstop;
++      extra_width[tabstop] = this_tab_size - 1;
++    }
++  /* Example of this calculation: if tabstop is 10, the tab starting at column
++     #103 has to expand into 8 spaces, covering columns 103-110, so that the
++     next character is at column #111.  So it takes up 7 more columns than
++     a space would have taken up.  */
++  ASSERT_EQ (7, extra_width[10]);
++
++  temp_source_file tmp (SELFTEST_LOCATION, ".c", content);
++  line_table_test ltt (case_);
++
++  linemap_add (line_table, LC_ENTER, false, tmp.get_filename (), 1);
++
++  location_t line_end = linemap_position_for_column (line_table, line_bytes);
++
++  /* Don't attempt to run the tests if column data might be unavailable.  */
++  if (line_end > LINE_MAP_MAX_LOCATION_WITH_COLS)
++    return;
++
++  /* Check that cpp_display_width handles the tabs as expected.  */
++  char_span lspan = location_get_source_line (tmp.get_filename (), 1);
++  ASSERT_EQ ('\t', *(lspan.get_buffer () + (tab_col - 1)));
++  for (int tabstop = 1; tabstop != num_tabstops; ++tabstop)
++    {
++      ASSERT_EQ (line_bytes + extra_width[tabstop],
++                cpp_display_width (lspan.get_buffer (), lspan.length (),
++                                   tabstop));
++      ASSERT_EQ (line_bytes + extra_width[tabstop],
++                location_compute_display_column (expand_location (line_end),
++                                                 tabstop));
++    }
++
++  /* Check that the tab is expanded to the expected number of spaces.  */
++  rich_location richloc (line_table,
++                        linemap_position_for_column (line_table,
++                                                     tab_col + 1));
++  for (int tabstop = 1; tabstop != num_tabstops; ++tabstop)
++    {
++      test_diagnostic_context dc;
++      dc.tabstop = tabstop;
++      layout test_layout (&dc, &richloc, DK_ERROR);
++      test_layout.print_line (1);
++      const char *out = pp_formatted_text (dc.printer);
++      ASSERT_EQ (NULL, strchr (out, '\t'));
++      const char *left_quote = strchr (out, '`');
++      const char *right_quote = strchr (out, '\'');
++      ASSERT_NE (NULL, left_quote);
++      ASSERT_NE (NULL, right_quote);
++      ASSERT_EQ (right_quote - left_quote, extra_width[tabstop] + 2);
++    }
++
++  /* Check that the line is offset properly and that the tab is broken up
++     into the expected number of spaces when it is the last character skipped
++     over.  */
++  for (int tabstop = 1; tabstop != num_tabstops; ++tabstop)
++    {
++      test_diagnostic_context dc;
++      dc.tabstop = tabstop;
++      static const int small_width = 24;
++      dc.caret_max_width = small_width - 4;
++      dc.min_margin_width = test_left_margin - test_linenum_sep + 1;
++      dc.show_line_numbers_p = true;
++      layout test_layout (&dc, &richloc, DK_ERROR);
++      test_layout.print_line (1);
++
++      /* We have arranged things so that two columns will be printed before
++        the caret.  If the tab results in more than one space, this should
++        produce two spaces in the output; otherwise, it will be a single space
++        preceded by the opening quote before the tab character.  */
++      const char *output1
++       = "   1 |   ' is a tab that occupies 1 byte and a variable number of "
++         "display columns, starting at column #103.\n"
++         "     |   ^\n\n";
++      const char *output2
++       = "   1 | ` ' is a tab that occupies 1 byte and a variable number of "
++         "display columns, starting at column #103.\n"
++         "     |   ^\n\n";
++      const char *expected_output = (extra_width[tabstop] ? output1 : output2);
++      ASSERT_STREQ (expected_output, pp_formatted_text (dc.printer));
++    }
++}
++
++
+ /* Verify that diagnostic_show_locus works sanely on UNKNOWN_LOCATION.  */
+ 
+ static void
+@@ -3854,6 +3994,27 @@ test_one_liner_labels_utf8 ()
+   }
+ }
+ 
++/* Make sure that colorization codes don't interrupt a multibyte
++   sequence, which would corrupt it.  */
++static void
++test_one_liner_colorized_utf8 ()
++{
++  test_diagnostic_context dc;
++  dc.colorize_source_p = true;
++  diagnostic_color_init (&dc, DIAGNOSTICS_COLOR_YES);
++  const location_t pi = linemap_position_for_column (line_table, 12);
++  rich_location richloc (line_table, pi);
++  diagnostic_show_locus (&dc, &richloc, DK_ERROR);
++
++  /* In order to avoid having the test depend on exactly how the colorization
++     was effected, just confirm there are two pi characters in the output.  */
++  const char *result = pp_formatted_text (dc.printer);
++  const char *null_term = result + strlen (result);
++  const char *first_pi = strstr (result, "\xcf\x80");
++  ASSERT_TRUE (first_pi && first_pi <= null_term - 2);
++  ASSERT_STR_CONTAINS (first_pi + 2, "\xcf\x80");
++}
++
+ /* Run the various one-liner tests.  */
+ 
+ static void
+@@ -3884,8 +4045,10 @@ test_diagnostic_show_locus_one_liner_utf
+   ASSERT_EQ (31, LOCATION_COLUMN (line_end));
+ 
+   char_span lspan = location_get_source_line (tmp.get_filename (), 1);
+-  ASSERT_EQ (25, cpp_display_width (lspan.get_buffer (), lspan.length ()));
+-  ASSERT_EQ (25, location_compute_display_column (expand_location (line_end)));
++  ASSERT_EQ (25, cpp_display_width (lspan.get_buffer (), lspan.length (),
++                                   def_tabstop));
++  ASSERT_EQ (25, location_compute_display_column (expand_location (line_end),
++                                                 def_tabstop));
+ 
+   test_one_liner_simple_caret_utf8 ();
+   test_one_liner_caret_and_range_utf8 ();
+@@ -3900,6 +4063,7 @@ test_diagnostic_show_locus_one_liner_utf
+   test_one_liner_many_fixits_1_utf8 ();
+   test_one_liner_many_fixits_2_utf8 ();
+   test_one_liner_labels_utf8 ();
++  test_one_liner_colorized_utf8 ();
+ }
+ 
+ /* Verify that gcc_rich_location::add_location_if_nearby works.  */
+@@ -4272,25 +4436,28 @@ test_overlapped_fixit_printing (const li
+     /* Unit-test the line_corrections machinery.  */
+     ASSERT_EQ (3, richloc.get_num_fixit_hints ());
+     const fixit_hint *hint_0 = richloc.get_fixit_hint (0);
+-    ASSERT_EQ (column_range (12, 12), get_affected_range (hint_0, CU_BYTES));
+     ASSERT_EQ (column_range (12, 12),
+-                          get_affected_range (hint_0, CU_DISPLAY_COLS));
+-    ASSERT_EQ (column_range (12, 22), get_printed_columns (hint_0));
++              get_affected_range (&dc, hint_0, CU_BYTES));
++    ASSERT_EQ (column_range (12, 12),
++              get_affected_range (&dc, hint_0, CU_DISPLAY_COLS));
++    ASSERT_EQ (column_range (12, 22), get_printed_columns (&dc, hint_0));
+     const fixit_hint *hint_1 = richloc.get_fixit_hint (1);
+-    ASSERT_EQ (column_range (18, 18), get_affected_range (hint_1, CU_BYTES));
+     ASSERT_EQ (column_range (18, 18),
+-                          get_affected_range (hint_1, CU_DISPLAY_COLS));
+-    ASSERT_EQ (column_range (18, 20), get_printed_columns (hint_1));
++              get_affected_range (&dc, hint_1, CU_BYTES));
++    ASSERT_EQ (column_range (18, 18),
++              get_affected_range (&dc, hint_1, CU_DISPLAY_COLS));
++    ASSERT_EQ (column_range (18, 20), get_printed_columns (&dc, hint_1));
+     const fixit_hint *hint_2 = richloc.get_fixit_hint (2);
+-    ASSERT_EQ (column_range (29, 28), get_affected_range (hint_2, CU_BYTES));
+     ASSERT_EQ (column_range (29, 28),
+-                          get_affected_range (hint_2, CU_DISPLAY_COLS));
+-    ASSERT_EQ (column_range (29, 29), get_printed_columns (hint_2));
++              get_affected_range (&dc, hint_2, CU_BYTES));
++    ASSERT_EQ (column_range (29, 28),
++              get_affected_range (&dc, hint_2, CU_DISPLAY_COLS));
++    ASSERT_EQ (column_range (29, 29), get_printed_columns (&dc, hint_2));
+ 
+     /* Add each hint in turn to a line_corrections instance,
+        and verify that they are consolidated into one correction instance
+        as expected.  */
+-    line_corrections lc (tmp.get_filename (), 1);
++    line_corrections lc (&dc, tmp.get_filename (), 1);
+ 
+     /* The first replace hint by itself.  */
+     lc.add_hint (hint_0);
+@@ -4484,25 +4651,28 @@ test_overlapped_fixit_printing_utf8 (con
+     /* Unit-test the line_corrections machinery.  */
+     ASSERT_EQ (3, richloc.get_num_fixit_hints ());
+     const fixit_hint *hint_0 = richloc.get_fixit_hint (0);
+-    ASSERT_EQ (column_range (14, 14), get_affected_range (hint_0, CU_BYTES));
++    ASSERT_EQ (column_range (14, 14),
++              get_affected_range (&dc, hint_0, CU_BYTES));
+     ASSERT_EQ (column_range (12, 12),
+-                          get_affected_range (hint_0, CU_DISPLAY_COLS));
+-    ASSERT_EQ (column_range (12, 22), get_printed_columns (hint_0));
++              get_affected_range (&dc, hint_0, CU_DISPLAY_COLS));
++    ASSERT_EQ (column_range (12, 22), get_printed_columns (&dc, hint_0));
+     const fixit_hint *hint_1 = richloc.get_fixit_hint (1);
+-    ASSERT_EQ (column_range (22, 22), get_affected_range (hint_1, CU_BYTES));
++    ASSERT_EQ (column_range (22, 22),
++              get_affected_range (&dc, hint_1, CU_BYTES));
+     ASSERT_EQ (column_range (18, 18),
+-                          get_affected_range (hint_1, CU_DISPLAY_COLS));
+-    ASSERT_EQ (column_range (18, 20), get_printed_columns (hint_1));
++              get_affected_range (&dc, hint_1, CU_DISPLAY_COLS));
++    ASSERT_EQ (column_range (18, 20), get_printed_columns (&dc, hint_1));
+     const fixit_hint *hint_2 = richloc.get_fixit_hint (2);
+-    ASSERT_EQ (column_range (35, 34), get_affected_range (hint_2, CU_BYTES));
++    ASSERT_EQ (column_range (35, 34),
++              get_affected_range (&dc, hint_2, CU_BYTES));
+     ASSERT_EQ (column_range (30, 29),
+-                          get_affected_range (hint_2, CU_DISPLAY_COLS));
+-    ASSERT_EQ (column_range (30, 30), get_printed_columns (hint_2));
++              get_affected_range (&dc, hint_2, CU_DISPLAY_COLS));
++    ASSERT_EQ (column_range (30, 30), get_printed_columns (&dc, hint_2));
+ 
+     /* Add each hint in turn to a line_corrections instance,
+        and verify that they are consolidated into one correction instance
+        as expected.  */
+-    line_corrections lc (tmp.get_filename (), 1);
++    line_corrections lc (&dc, tmp.get_filename (), 1);
+ 
+     /* The first replace hint by itself.  */
+     lc.add_hint (hint_0);
+@@ -4689,6 +4859,8 @@ test_overlapped_fixit_printing_2 (const
+ 
+   /* Two insertions, in the wrong order.  */
+   {
++    test_diagnostic_context dc;
++
+     rich_location richloc (line_table, col_20);
+     richloc.add_fixit_insert_before (col_23, "{");
+     richloc.add_fixit_insert_before (col_21, "}");
+@@ -4696,14 +4868,15 @@ test_overlapped_fixit_printing_2 (const
+     /* These fixits should be accepted; they can't be consolidated.  */
+     ASSERT_EQ (2, richloc.get_num_fixit_hints ());
+     const fixit_hint *hint_0 = richloc.get_fixit_hint (0);
+-    ASSERT_EQ (column_range (23, 22), get_affected_range (hint_0, CU_BYTES));
+-    ASSERT_EQ (column_range (23, 23), get_printed_columns (hint_0));
++    ASSERT_EQ (column_range (23, 22),
++              get_affected_range (&dc, hint_0, CU_BYTES));
++    ASSERT_EQ (column_range (23, 23), get_printed_columns (&dc, hint_0));
+     const fixit_hint *hint_1 = richloc.get_fixit_hint (1);
+-    ASSERT_EQ (column_range (21, 20), get_affected_range (hint_1, CU_BYTES));
+-    ASSERT_EQ (column_range (21, 21), get_printed_columns (hint_1));
++    ASSERT_EQ (column_range (21, 20),
++              get_affected_range (&dc, hint_1, CU_BYTES));
++    ASSERT_EQ (column_range (21, 21), get_printed_columns (&dc, hint_1));
+ 
+     /* Verify that they're printed correctly.  */
+-    test_diagnostic_context dc;
+     diagnostic_show_locus (&dc, &richloc, DK_ERROR);
+     ASSERT_STREQ (" int a5[][0][0] = { 1, 2 };\n"
+                  "                    ^\n"
+@@ -4955,6 +5128,65 @@ test_fixit_deletion_affecting_newline (c
+                pp_formatted_text (dc.printer));
+ }
+ 
++static void
++test_tab_expansion (const line_table_case &case_)
++{
++  /* Create a tempfile and write some text to it.  This example uses a tabstop
++     of 8, as the column numbers attempt to indicate:
++
++    .....................000.01111111111.22222333333  display
++    .....................123.90123456789.56789012345  columns  */
++  const char *content = "  \t   This: `\t' is a tab.\n";
++  /* ....................000 00000011111 11111222222  byte
++     ....................123 45678901234 56789012345  columns  */
++
++  const int tabstop = 8;
++  const int first_non_ws_byte_col = 7;
++  const int right_quote_byte_col = 15;
++  const int last_byte_col = 25;
++  ASSERT_EQ (35, cpp_display_width (content, last_byte_col, tabstop));
++
++  temp_source_file tmp (SELFTEST_LOCATION, ".c", content);
++  line_table_test ltt (case_);
++  linemap_add (line_table, LC_ENTER, false, tmp.get_filename (), 1);
++
++  /* Don't attempt to run the tests if column data might be unavailable.  */
++  location_t line_end = linemap_position_for_column (line_table, last_byte_col);
++  if (line_end > LINE_MAP_MAX_LOCATION_WITH_COLS)
++    return;
++
++  /* Check that the leading whitespace with mixed tabs and spaces is expanded
++     into 11 spaces.  Recall that print_line() also puts one space before
++     everything too.  */
++  {
++    test_diagnostic_context dc;
++    dc.tabstop = tabstop;
++    rich_location richloc (line_table,
++                          linemap_position_for_column (line_table,
++                                                       first_non_ws_byte_col));
++    layout test_layout (&dc, &richloc, DK_ERROR);
++    test_layout.print_line (1);
++    ASSERT_STREQ ("            This: `      ' is a tab.\n"
++                 "            ^\n",
++                 pp_formatted_text (dc.printer));
++  }
++
++  /* Confirm the display width was tracked correctly across the internal tab
++     as well.  */
++  {
++    test_diagnostic_context dc;
++    dc.tabstop = tabstop;
++    rich_location richloc (line_table,
++                          linemap_position_for_column (line_table,
++                                                       right_quote_byte_col));
++    layout test_layout (&dc, &richloc, DK_ERROR);
++    test_layout.print_line (1);
++    ASSERT_STREQ ("            This: `      ' is a tab.\n"
++                 "                         ^\n",
++                 pp_formatted_text (dc.printer));
++  }
++}
++
+ /* Verify that line numbers are correctly printed for the case of
+    a multiline range in which the width of the line numbers changes
+    (e.g. from "9" to "10").  */
+@@ -5012,6 +5244,7 @@ diagnostic_show_locus_c_tests ()
+   test_layout_range_for_multiple_lines ();
+ 
+   for_each_line_table_case (test_layout_x_offset_display_utf8);
++  for_each_line_table_case (test_layout_x_offset_display_tab);
+ 
+   test_get_line_bytes_without_trailing_whitespace ();
+ 
+@@ -5029,6 +5262,7 @@ diagnostic_show_locus_c_tests ()
+   for_each_line_table_case (test_fixit_insert_containing_newline_2);
+   for_each_line_table_case (test_fixit_replace_containing_newline);
+   for_each_line_table_case (test_fixit_deletion_affecting_newline);
++  for_each_line_table_case (test_tab_expansion);
+ 
+   test_line_numbers_multiline_range ();
+ }
+diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
+--- a/gcc/doc/invoke.texi       2021-12-24 20:23:46.876739587 -0800
++++ b/gcc/doc/invoke.texi       2021-12-25 01:20:53.487636494 -0800
+@@ -293,7 +293,9 @@ Objective-C and Objective-C++ Dialects}.
+ -fdiagnostics-show-template-tree  -fno-elide-type @gol
+ -fdiagnostics-path-format=@r{[}none@r{|}separate-events@r{|}inline-events@r{]} @gol
+ -fdiagnostics-show-path-depths @gol
+--fno-show-column}
++-fno-show-column @gol
++-fdiagnostics-column-unit=@r{[}display@r{|}byte@r{]} @gol
++-fdiagnostics-column-origin=@var{origin}}
+ 
+ @item Warning Options
+ @xref{Warning Options,,Options to Request or Suppress Warnings}.
+@@ -4424,6 +4426,31 @@ Do not print column numbers in diagnosti
+ diagnostics are being scanned by a program that does not understand the
+ column numbers, such as @command{dejagnu}.
+ 
++@item -fdiagnostics-column-unit=@var{UNIT}
++@opindex fdiagnostics-column-unit
++Select the units for the column number.  This affects traditional diagnostics
++(in the absence of @option{-fno-show-column}), as well as JSON format
++diagnostics if requested.
++
++The default @var{UNIT}, @samp{display}, considers the number of display
++columns occupied by each character.  This may be larger than the number
++of bytes required to encode the character, in the case of tab
++characters, or it may be smaller, in the case of multibyte characters.
++For example, the character ``GREEK SMALL LETTER PI (U+03C0)'' occupies one
++display column, and its UTF-8 encoding requires two bytes; the character
++``SLIGHTLY SMILING FACE (U+1F642)'' occupies two display columns, and
++its UTF-8 encoding requires four bytes.
++
++Setting @var{UNIT} to @samp{byte} changes the column number to the raw byte
++count in all cases, as was traditionally output by GCC prior to version 11.1.0.
++
++@item -fdiagnostics-column-origin=@var{ORIGIN}
++@opindex fdiagnostics-column-origin
++Select the origin for column numbers, i.e. the column number assigned to the
++first column.  The default value of 1 corresponds to traditional GCC
++behavior and to the GNU style guide.  Some utilities may perform better with an
++origin of 0; any non-negative value may be specified.
++
+ @item -fdiagnostics-format=@var{FORMAT}
+ @opindex fdiagnostics-format
+ Select a different format for printing diagnostics.
+@@ -4459,11 +4486,15 @@ might be printed in JSON form (after for
+         "locations": [
+             @{
+                 "caret": @{
++                   "display-column": 3,
++                   "byte-column": 3,
+                     "column": 3,
+                     "file": "misleading-indentation.c",
+                     "line": 15
+                 @},
+                 "finish": @{
++                   "display-column": 4,
++                   "byte-column": 4,
+                     "column": 4,
+                     "file": "misleading-indentation.c",
+                     "line": 15
+@@ -4479,6 +4510,8 @@ might be printed in JSON form (after for
+                 "locations": [
+                     @{
+                         "caret": @{
++                           "display-column": 5,
++                           "byte-column": 5,
+                             "column": 5,
+                             "file": "misleading-indentation.c",
+                             "line": 17
+@@ -4488,6 +4521,7 @@ might be printed in JSON form (after for
+                 "message": "...this statement, but the latter is @dots{}"
+             @}
+         ]
++       "column-origin": 1,
+     @},
+     @dots{}
+ ]
+@@ -4500,10 +4534,34 @@ A diagnostic has a @code{kind}.  If this
+ an @code{option} key describing the command-line option controlling the
+ warning.
+ 
+-A diagnostic can contain zero or more locations.  Each location has up
+-to three positions within it: a @code{caret} position and optional
+-@code{start} and @code{finish} positions.  A location can also have
+-an optional @code{label} string.  For example, this error:
++A diagnostic can contain zero or more locations.  Each location has an
++optional @code{label} string and up to three positions within it: a
++@code{caret} position and optional @code{start} and @code{finish} positions.
++A position is described by a @code{file} name, a @code{line} number, and
++three numbers indicating a column position:
++@itemize @bullet
++
++@item
++@code{display-column} counts display columns, accounting for tabs and
++multibyte characters.
++
++@item
++@code{byte-column} counts raw bytes.
++
++@item
++@code{column} is equal to one of
++the previous two, as dictated by the @option{-fdiagnostics-column-unit}
++option.
++
++@end itemize
++All three columns are relative to the origin specified by
++@option{-fdiagnostics-column-origin}, which is typically equal to 1 but may
++be set, for instance, to 0 for compatibility with other utilities that
++number columns from 0.  The column origin is recorded in the JSON output in
++the @code{column-origin} tag.  In the remaining examples below, the extra
++column number outputs have been omitted for brevity.
++
++For example, this error:
+ 
+ @smallexample
+ bad-binary-ops.c:64:23: error: invalid operands to binary + (have 'S' @{aka
+diff --git a/gcc/input.c b/gcc/input.c
+--- a/gcc/input.c       2020-07-22 23:35:17.664388078 -0700
++++ b/gcc/input.c       2021-12-25 01:20:53.487636494 -0800
+@@ -913,7 +913,7 @@ make_location (location_t caret, source_
+    source line in order to calculate the display width.  If that cannot be done
+    for any reason, then returns the byte column as a fallback.  */
+ int
+-location_compute_display_column (expanded_location exploc)
++location_compute_display_column (expanded_location exploc, int tabstop)
+ {
+   if (!(exploc.file && *exploc.file && exploc.line && exploc.column))
+     return exploc.column;
+@@ -921,7 +921,7 @@ location_compute_display_column (expande
+   /* If line is NULL, this function returns exploc.column which is the
+      desired fallback.  */
+   return cpp_byte_column_to_display_column (line.get_buffer (), line.length (),
+-                                           exploc.column);
++                                           exploc.column, tabstop);
+ }
+ 
+ /* Dump statistics to stderr about the memory usage of the line_table
+@@ -3608,33 +3608,46 @@ test_line_offset_overflow ()
+ 
+ void test_cpp_utf8 ()
+ {
++  const int def_tabstop = 8;
+   /* Verify that wcwidth of invalid UTF-8 or control bytes is 1.  */
+   {
+-    int w_bad = cpp_display_width ("\xf0!\x9f!\x98!\x82!", 8);
++    int w_bad = cpp_display_width ("\xf0!\x9f!\x98!\x82!", 8, def_tabstop);
+     ASSERT_EQ (8, w_bad);
+-    int w_ctrl = cpp_display_width ("\r\t\n\v\0\1", 6);
+-    ASSERT_EQ (6, w_ctrl);
++    int w_ctrl = cpp_display_width ("\r\n\v\0\1", 5, def_tabstop);
++    ASSERT_EQ (5, w_ctrl);
+   }
+ 
+   /* Verify that wcwidth of valid UTF-8 is as expected.  */
+   {
+-    const int w_pi = cpp_display_width ("\xcf\x80", 2);
++    const int w_pi = cpp_display_width ("\xcf\x80", 2, def_tabstop);
+     ASSERT_EQ (1, w_pi);
+-    const int w_emoji = cpp_display_width ("\xf0\x9f\x98\x82", 4);
++    const int w_emoji = cpp_display_width ("\xf0\x9f\x98\x82", 4, def_tabstop);
+     ASSERT_EQ (2, w_emoji);
+-    const int w_umlaut_precomposed = cpp_display_width ("\xc3\xbf", 2);
++    const int w_umlaut_precomposed = cpp_display_width ("\xc3\xbf", 2,
++                                                       def_tabstop);
+     ASSERT_EQ (1, w_umlaut_precomposed);
+-    const int w_umlaut_combining = cpp_display_width ("y\xcc\x88", 3);
++    const int w_umlaut_combining = cpp_display_width ("y\xcc\x88", 3,
++                                                     def_tabstop);
+     ASSERT_EQ (1, w_umlaut_combining);
+-    const int w_han = cpp_display_width ("\xe4\xb8\xba", 3);
++    const int w_han = cpp_display_width ("\xe4\xb8\xba", 3, def_tabstop);
+     ASSERT_EQ (2, w_han);
+-    const int w_ascii = cpp_display_width ("GCC", 3);
++    const int w_ascii = cpp_display_width ("GCC", 3, def_tabstop);
+     ASSERT_EQ (3, w_ascii);
+     const int w_mixed = cpp_display_width ("\xcf\x80 = 3.14 \xf0\x9f\x98\x82"
+-                                          "\x9f! \xe4\xb8\xba y\xcc\x88", 24);
++                                          "\x9f! \xe4\xb8\xba y\xcc\x88",
++                                          24, def_tabstop);
+     ASSERT_EQ (18, w_mixed);
+   }
+ 
++  /* Verify that display width properly expands tabs.  */
++  {
++    const char *tstr = "\tabc\td";
++    ASSERT_EQ (6, cpp_display_width (tstr, 6, 1));
++    ASSERT_EQ (10, cpp_display_width (tstr, 6, 3));
++    ASSERT_EQ (17, cpp_display_width (tstr, 6, 8));
++    ASSERT_EQ (1, cpp_display_column_to_byte_column (tstr, 6, 7, 8));
++  }
++
+   /* Verify that cpp_byte_column_to_display_column can go past the end,
+      and similar edge cases.  */
+   {
+@@ -3645,10 +3658,13 @@ void test_cpp_utf8 ()
+       /* 111122223456
+         Byte columns.  */
+ 
+-    ASSERT_EQ (5, cpp_display_width (str, 6));
+-    ASSERT_EQ (105, cpp_byte_column_to_display_column (str, 6, 106));
+-    ASSERT_EQ (10000, cpp_byte_column_to_display_column (NULL, 0, 10000));
+-    ASSERT_EQ (0, cpp_byte_column_to_display_column (NULL, 10000, 0));
++    ASSERT_EQ (5, cpp_display_width (str, 6, def_tabstop));
++    ASSERT_EQ (105,
++              cpp_byte_column_to_display_column (str, 6, 106, def_tabstop));
++    ASSERT_EQ (10000,
++              cpp_byte_column_to_display_column (NULL, 0, 10000, def_tabstop));
++    ASSERT_EQ (0,
++              cpp_byte_column_to_display_column (NULL, 10000, 0, def_tabstop));
+   }
+ 
+   /* Verify that cpp_display_column_to_byte_column can go past the end,
+@@ -3662,21 +3678,25 @@ void test_cpp_utf8 ()
+       /* 000000000000000000000000000000000111111
+         111122223333444456666777788889999012345
+         Byte columns.  */
+-    ASSERT_EQ (4, cpp_display_column_to_byte_column (str, 15, 2));
+-    ASSERT_EQ (15, cpp_display_column_to_byte_column (str, 15, 11));
+-    ASSERT_EQ (115, cpp_display_column_to_byte_column (str, 15, 111));
+-    ASSERT_EQ (10000, cpp_display_column_to_byte_column (NULL, 0, 10000));
+-    ASSERT_EQ (0, cpp_display_column_to_byte_column (NULL, 10000, 0));
++    ASSERT_EQ (4, cpp_display_column_to_byte_column (str, 15, 2, def_tabstop));
++    ASSERT_EQ (15,
++              cpp_display_column_to_byte_column (str, 15, 11, def_tabstop));
++    ASSERT_EQ (115,
++              cpp_display_column_to_byte_column (str, 15, 111, def_tabstop));
++    ASSERT_EQ (10000,
++              cpp_display_column_to_byte_column (NULL, 0, 10000, def_tabstop));
++    ASSERT_EQ (0,
++              cpp_display_column_to_byte_column (NULL, 10000, 0, def_tabstop));
+ 
+     /* Verify that we do not interrupt a UTF-8 sequence.  */
+-    ASSERT_EQ (4, cpp_display_column_to_byte_column (str, 15, 1));
++    ASSERT_EQ (4, cpp_display_column_to_byte_column (str, 15, 1, def_tabstop));
+ 
+     for (int byte_col = 1; byte_col <= 15; ++byte_col)
+       {
+-       const int disp_col = cpp_byte_column_to_display_column (str, 15,
+-                                                               byte_col);
+-       const int byte_col2 = cpp_display_column_to_byte_column (str, 15,
+-                                                                disp_col);
++       const int disp_col
++         = cpp_byte_column_to_display_column (str, 15, byte_col, def_tabstop);
++       const int byte_col2
++         = cpp_display_column_to_byte_column (str, 15, disp_col, def_tabstop);
+ 
+        /* If we ask for the display column in the middle of a UTF-8
+           sequence, it will return the length of the partial sequence,
+diff --git a/gcc/input.h b/gcc/input.h
+--- a/gcc/input.h       2020-07-22 23:35:17.664388078 -0700
++++ b/gcc/input.h       2021-12-25 01:20:53.487636494 -0800
+@@ -38,7 +38,9 @@ STATIC_ASSERT (BUILTINS_LOCATION < RESER
+ 
+ extern bool is_location_from_builtin_token (location_t);
+ extern expanded_location expand_location (location_t);
+-extern int location_compute_display_column (expanded_location);
++
++extern int location_compute_display_column (expanded_location exploc,
++                                           int tabstop);
+ 
+ /* A class capturing the bounds of a buffer, to allow for run-time
+    bounds-checking in a checked build.  */
+diff --git a/gcc/opts.c b/gcc/opts.c
+--- a/gcc/opts.c        2020-07-22 23:35:17.708388562 -0700
++++ b/gcc/opts.c        2021-12-25 01:20:53.487636494 -0800
+@@ -2439,6 +2439,14 @@ common_handle_option (struct gcc_options
+       dc->parseable_fixits_p = value;
+       break;
+ 
++    case OPT_fdiagnostics_column_unit_:
++      dc->column_unit = (enum diagnostics_column_unit)value;
++      break;
++
++    case OPT_fdiagnostics_column_origin_:
++      dc->column_origin = value;
++      break;
++
+     case OPT_fdiagnostics_show_cwe:
+       dc->show_cwe = value;
+       break;
+@@ -2825,6 +2833,12 @@ common_handle_option (struct gcc_options
+       check_alignment_argument (loc, arg, "functions");
+       break;
+ 
++    case OPT_ftabstop_:
++      /* It is documented that we silently ignore silly values.  */
++      if (value >= 1 && value <= 100)
++       dc->tabstop = value;
++      break;
++
+     default:
+       /* If the flag was handled in a standard way, assume the lack of
+         processing here is intentional.  */
+diff --git a/gcc/testsuite/c-c++-common/diagnostic-format-json-1.c b/gcc/testsuite/c-c++-common/diagnostic-format-json-1.c
+--- a/gcc/testsuite/c-c++-common/diagnostic-format-json-1.c     2020-07-22 23:35:17.908390765 -0700
++++ b/gcc/testsuite/c-c++-common/diagnostic-format-json-1.c     2021-12-25 01:20:53.487636494 -0800
+@@ -8,17 +8,22 @@
+    We can't rely on any ordering of the keys.  */
+ 
+ /* { dg-regexp "\"kind\": \"error\"" } */
++/* { dg-regexp "\"column-origin\": 1" } */
+ /* { dg-regexp "\"message\": \"#error message\"" } */
+ 
+ /* { dg-regexp "\"caret\": \{" } */
+ /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-1.c\"" } */
+ /* { dg-regexp "\"line\": 4" } */
+ /* { dg-regexp "\"column\": 2" } */
++/* { dg-regexp "\"display-column\": 2" } */
++/* { dg-regexp "\"byte-column\": 2" } */
+ 
+ /* { dg-regexp "\"finish\": \{" } */
+ /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-1.c\"" } */
+ /* { dg-regexp "\"line\": 4" } */
+ /* { dg-regexp "\"column\": 6" } */
++/* { dg-regexp "\"display-column\": 6" } */
++/* { dg-regexp "\"byte-column\": 6" } */
+ 
+ /* { dg-regexp "\"locations\": \[\[\{\}, \]*\]" } */
+ /* { dg-regexp "\"children\": \[\[\]\[\]\]" } */
+diff --git a/gcc/testsuite/c-c++-common/diagnostic-format-json-2.c b/gcc/testsuite/c-c++-common/diagnostic-format-json-2.c
+--- a/gcc/testsuite/c-c++-common/diagnostic-format-json-2.c     2020-07-22 23:35:17.908390765 -0700
++++ b/gcc/testsuite/c-c++-common/diagnostic-format-json-2.c     2021-12-25 01:20:53.487636494 -0800
+@@ -8,6 +8,7 @@
+    We can't rely on any ordering of the keys.  */
+ 
+ /* { dg-regexp "\"kind\": \"warning\"" } */
++/* { dg-regexp "\"column-origin\": 1" } */
+ /* { dg-regexp "\"message\": \"#warning message\"" } */
+ /* { dg-regexp "\"option\": \"-Wcpp\"" } */
+ /* { dg-regexp "\"option_url\": \"https:\[^\n\r\"\]*#index-Wcpp\"" } */
+@@ -16,11 +17,15 @@
+ /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-2.c\"" } */
+ /* { dg-regexp "\"line\": 4" } */
+ /* { dg-regexp "\"column\": 2" } */
++/* { dg-regexp "\"display-column\": 2" } */
++/* { dg-regexp "\"byte-column\": 2" } */
+ 
+ /* { dg-regexp "\"finish\": \{" } */
+ /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-2.c\"" } */
+ /* { dg-regexp "\"line\": 4" } */
+ /* { dg-regexp "\"column\": 8" } */
++/* { dg-regexp "\"display-column\": 8" } */
++/* { dg-regexp "\"byte-column\": 8" } */
+ 
+ /* { dg-regexp "\"locations\": \[\[\{\}, \]*\]" } */
+ /* { dg-regexp "\"children\": \[\[\]\[\]\]" } */
+diff --git a/gcc/testsuite/c-c++-common/diagnostic-format-json-3.c b/gcc/testsuite/c-c++-common/diagnostic-format-json-3.c
+--- a/gcc/testsuite/c-c++-common/diagnostic-format-json-3.c     2020-07-22 23:35:17.908390765 -0700
++++ b/gcc/testsuite/c-c++-common/diagnostic-format-json-3.c     2021-12-25 01:20:53.487636494 -0800
+@@ -8,6 +8,7 @@
+    We can't rely on any ordering of the keys.  */
+ 
+ /* { dg-regexp "\"kind\": \"error\"" } */
++/* { dg-regexp "\"column-origin\": 1" } */
+ /* { dg-regexp "\"message\": \"#warning message\"" } */
+ /* { dg-regexp "\"option\": \"-Werror=cpp\"" } */
+ /* { dg-regexp "\"option_url\": \"https:\[^\n\r\"\]*#index-Wcpp\"" } */
+@@ -16,11 +17,15 @@
+ /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-3.c\"" } */
+ /* { dg-regexp "\"line\": 4" } */
+ /* { dg-regexp "\"column\": 2" } */
++/* { dg-regexp "\"display-column\": 2" } */
++/* { dg-regexp "\"byte-column\": 2" } */
+ 
+ /* { dg-regexp "\"finish\": \{" } */
+ /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-3.c\"" } */
+ /* { dg-regexp "\"line\": 4" } */
+ /* { dg-regexp "\"column\": 8" } */
++/* { dg-regexp "\"display-column\": 8" } */
++/* { dg-regexp "\"byte-column\": 8" } */
+ 
+ /* { dg-regexp "\"locations\": \[\[\{\}, \]*\]" } */
+ /* { dg-regexp "\"children\": \[\[\]\[\]\]" } */
+diff --git a/gcc/testsuite/c-c++-common/diagnostic-format-json-4.c b/gcc/testsuite/c-c++-common/diagnostic-format-json-4.c
+--- a/gcc/testsuite/c-c++-common/diagnostic-format-json-4.c     2020-07-22 23:35:17.908390765 -0700
++++ b/gcc/testsuite/c-c++-common/diagnostic-format-json-4.c     2021-12-25 01:20:53.487636494 -0800
+@@ -24,15 +24,20 @@ int test (void)
+ /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-4.c\"" } */
+ /* { dg-regexp "\"line\": 8" } */
+ /* { dg-regexp "\"column\": 5" } */
++/* { dg-regexp "\"display-column\": 5" } */
++/* { dg-regexp "\"byte-column\": 5" } */
+ 
+ /* { dg-regexp "\"finish\": \{" } */
+ /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-4.c\"" } */
+ /* { dg-regexp "\"line\": 8" } */
+ /* { dg-regexp "\"column\": 10" } */
++/* { dg-regexp "\"display-column\": 10" } */
++/* { dg-regexp "\"byte-column\": 10" } */
+ 
+ /* The outer diagnostic.  */
+ 
+ /* { dg-regexp "\"kind\": \"warning\"" } */
++/* { dg-regexp "\"column-origin\": 1" } */
+ /* { dg-regexp "\"message\": \"this 'if' clause does not guard...\"" } */
+ /* { dg-regexp "\"option\": \"-Wmisleading-indentation\"" } */
+ /* { dg-regexp "\"option_url\": \"https:\[^\n\r\"\]*#index-Wmisleading-indentation\"" } */
+@@ -41,11 +46,15 @@ int test (void)
+ /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-4.c\"" } */
+ /* { dg-regexp "\"line\": 6" } */
+ /* { dg-regexp "\"column\": 3" } */
++/* { dg-regexp "\"display-column\": 3" } */
++/* { dg-regexp "\"byte-column\": 3" } */
+ 
+ /* { dg-regexp "\"finish\": \{" } */
+ /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-4.c\"" } */
+ /* { dg-regexp "\"line\": 6" } */
+ /* { dg-regexp "\"column\": 4" } */
++/* { dg-regexp "\"display-column\": 4" } */
++/* { dg-regexp "\"byte-column\": 4" } */
+ 
+ /* More from the nested diagnostic (we can't guarantee what order the
+    "file" keys are consumed).  */
+diff --git a/gcc/testsuite/c-c++-common/diagnostic-format-json-5.c b/gcc/testsuite/c-c++-common/diagnostic-format-json-5.c
+--- a/gcc/testsuite/c-c++-common/diagnostic-format-json-5.c     2020-07-22 23:35:17.908390765 -0700
++++ b/gcc/testsuite/c-c++-common/diagnostic-format-json-5.c     2021-12-25 01:20:53.487636494 -0800
+@@ -13,6 +13,7 @@ int test (struct s *ptr)
+    We can't rely on any ordering of the keys.  */
+ 
+ /* { dg-regexp "\"kind\": \"error\"" } */
++/* { dg-regexp "\"column-origin\": 1" } */
+ /* { dg-regexp "\"message\": \".*\"" } */
+ 
+ /* Verify fix-it hints.  */
+@@ -23,11 +24,15 @@ int test (struct s *ptr)
+ /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-5.c\"" } */
+ /* { dg-regexp "\"line\": 8" } */
+ /* { dg-regexp "\"column\": 15" } */
++/* { dg-regexp "\"display-column\": 15" } */
++/* { dg-regexp "\"byte-column\": 15" } */
+ 
+ /* { dg-regexp "\"next\": \{" } */
+ /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-5.c\"" } */
+ /* { dg-regexp "\"line\": 8" } */
+ /* { dg-regexp "\"column\": 21" } */
++/* { dg-regexp "\"display-column\": 21" } */
++/* { dg-regexp "\"byte-column\": 21" } */
+ 
+ /* { dg-regexp "\"fixits\": \[\[\{\}, \]*\]" } */
+ 
+@@ -35,11 +40,15 @@ int test (struct s *ptr)
+ /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-5.c\"" } */
+ /* { dg-regexp "\"line\": 8" } */
+ /* { dg-regexp "\"column\": 15" } */
++/* { dg-regexp "\"display-column\": 15" } */
++/* { dg-regexp "\"byte-column\": 15" } */
+ 
+ /* { dg-regexp "\"finish\": \{" } */
+ /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-5.c\"" } */
+ /* { dg-regexp "\"line\": 8" } */
+ /* { dg-regexp "\"column\": 20" } */
++/* { dg-regexp "\"display-column\": 20" } */
++/* { dg-regexp "\"byte-column\": 20" } */
+ 
+ /* { dg-regexp "\"locations\": \[\[\{\}, \]*\]" } */
+ /* { dg-regexp "\"children\": \[\[\]\[\]\]" } */
+diff --git a/gcc/testsuite/c-c++-common/diagnostic-units-1.c b/gcc/testsuite/c-c++-common/diagnostic-units-1.c
+--- a/gcc/testsuite/c-c++-common/diagnostic-units-1.c   1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/diagnostic-units-1.c   2021-12-25 01:20:53.487636494 -0800
+@@ -0,0 +1,28 @@
++/* { dg-do compile } */
++/* { dg-additional-options "-fdiagnostics-column-unit=byte -fshow-column -fdiagnostics-show-caret -Wmultichar" } */
++
++/* column units: bytes (via arg)
++   column origin: 1 (via default)
++   tabstop: 8 (via default) */
++
++/* This line starts with a tab.  */
++       int c1 = 'c1'; /* { dg-warning "11: multi-character character constant" } */
++/* { dg-begin-multiline-output "" }
++         int c1 = 'c1';
++                  ^~~~
++   { dg-end-multiline-output "" } */
++
++/* This line starts with <tabstop> spaces.  */
++        int c2 = 'c2'; /* { dg-warning "18: multi-character character constant" } */
++/* { dg-begin-multiline-output "" }
++         int c2 = 'c2';
++                  ^~~~
++   { dg-end-multiline-output "" } */
++
++/* This line starts with <tabstop> spaces and has an internal tab after
++   a space.  */
++        int c3 =       'c3'; /* { dg-warning "19: multi-character character constant" } */
++/* { dg-begin-multiline-output "" }
++         int c3 =        'c3';
++                         ^~~~
++   { dg-end-multiline-output "" } */
+diff --git a/gcc/testsuite/c-c++-common/diagnostic-units-2.c b/gcc/testsuite/c-c++-common/diagnostic-units-2.c
+--- a/gcc/testsuite/c-c++-common/diagnostic-units-2.c   1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/diagnostic-units-2.c   2021-12-25 01:20:53.487636494 -0800
+@@ -0,0 +1,28 @@
++/* { dg-do compile } */
++/* { dg-additional-options "-fdiagnostics-column-unit=display -fshow-column -fdiagnostics-show-caret -Wmultichar" } */
++
++/* column units: display (via arg)
++   column origin: 1 (via default)
++   tabstop: 8 (via default) */
++
++/* This line starts with a tab.  */
++       int c1 = 'c1'; /* { dg-warning "18: multi-character character constant" } */
++/* { dg-begin-multiline-output "" }
++         int c1 = 'c1';
++                  ^~~~
++   { dg-end-multiline-output "" } */
++
++/* This line starts with <tabstop> spaces.  */
++        int c2 = 'c2'; /* { dg-warning "18: multi-character character constant" } */
++/* { dg-begin-multiline-output "" }
++         int c2 = 'c2';
++                  ^~~~
++   { dg-end-multiline-output "" } */
++
++/* This line starts with <tabstop> spaces and has an internal tab after
++   a space.  */
++        int c3 =       'c3'; /* { dg-warning "25: multi-character character constant" } */
++/* { dg-begin-multiline-output "" }
++         int c3 =        'c3';
++                         ^~~~
++   { dg-end-multiline-output "" } */
+diff --git a/gcc/testsuite/c-c++-common/diagnostic-units-3.c b/gcc/testsuite/c-c++-common/diagnostic-units-3.c
+--- a/gcc/testsuite/c-c++-common/diagnostic-units-3.c   1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/diagnostic-units-3.c   2021-12-25 01:20:53.487636494 -0800
+@@ -0,0 +1,28 @@
++/* { dg-do compile } */
++/* { dg-additional-options "-fdiagnostics-column-unit=byte -fshow-column -fdiagnostics-show-caret -ftabstop=200 -Wmultichar" } */
++
++/* column units: bytes (via arg)
++   column origin: 1 (via fallback from overly large argument)
++   tabstop: 8 (via default) */
++
++/* This line starts with a tab.  */
++       int c1 = 'c1'; /* { dg-warning "11: multi-character character constant" } */
++/* { dg-begin-multiline-output "" }
++         int c1 = 'c1';
++                  ^~~~
++   { dg-end-multiline-output "" } */
++
++/* This line starts with <tabstop> spaces.  */
++        int c2 = 'c2'; /* { dg-warning "18: multi-character character constant" } */
++/* { dg-begin-multiline-output "" }
++         int c2 = 'c2';
++                  ^~~~
++   { dg-end-multiline-output "" } */
++
++/* This line starts with <tabstop> spaces and has an internal tab after
++   a space.  */
++        int c3 =       'c3'; /* { dg-warning "19: multi-character character constant" } */
++/* { dg-begin-multiline-output "" }
++         int c3 =        'c3';
++                         ^~~~
++   { dg-end-multiline-output "" } */
+diff --git a/gcc/testsuite/c-c++-common/diagnostic-units-4.c b/gcc/testsuite/c-c++-common/diagnostic-units-4.c
+--- a/gcc/testsuite/c-c++-common/diagnostic-units-4.c   1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/diagnostic-units-4.c   2021-12-25 01:20:53.487636494 -0800
+@@ -0,0 +1,28 @@
++/* { dg-do compile } */
++/* { dg-additional-options "-fdiagnostics-column-unit=byte -fshow-column -fdiagnostics-show-caret -fdiagnostics-column-origin=0 -Wmultichar" } */
++
++/* column units: bytes (via arg)
++   column origin: 0 (via arg)
++   tabstop: 8 (via default) */
++
++/* This line starts with a tab.  */
++       int c1 = 'c1'; /* { dg-warning "10: multi-character character constant" } */
++/* { dg-begin-multiline-output "" }
++         int c1 = 'c1';
++                  ^~~~
++   { dg-end-multiline-output "" } */
++
++/* This line starts with <tabstop> spaces.  */
++        int c2 = 'c2'; /* { dg-warning "17: multi-character character constant" } */
++/* { dg-begin-multiline-output "" }
++         int c2 = 'c2';
++                  ^~~~
++   { dg-end-multiline-output "" } */
++
++/* This line starts with <tabstop> spaces and has an internal tab after
++   a space.  */
++        int c3 =       'c3'; /* { dg-warning "18: multi-character character constant" } */
++/* { dg-begin-multiline-output "" }
++         int c3 =        'c3';
++                         ^~~~
++   { dg-end-multiline-output "" } */
+diff --git a/gcc/testsuite/c-c++-common/diagnostic-units-5.c b/gcc/testsuite/c-c++-common/diagnostic-units-5.c
+--- a/gcc/testsuite/c-c++-common/diagnostic-units-5.c   1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/diagnostic-units-5.c   2021-12-25 01:20:53.491636427 -0800
+@@ -0,0 +1,28 @@
++/* { dg-do compile } */
++/* { dg-additional-options "-fdiagnostics-column-unit=display -fshow-column -fdiagnostics-show-caret -fdiagnostics-column-origin=0 -Wmultichar" } */
++
++/* column units: display (via arg)
++   column origin: 0 (via arg)
++   tabstop: 8 (via default) */
++
++/* This line starts with a tab.  */
++       int c1 = 'c1'; /* { dg-warning "17: multi-character character constant" } */
++/* { dg-begin-multiline-output "" }
++         int c1 = 'c1';
++                  ^~~~
++   { dg-end-multiline-output "" } */
++
++/* This line starts with <tabstop> spaces.  */
++        int c2 = 'c2'; /* { dg-warning "17: multi-character character constant" } */
++/* { dg-begin-multiline-output "" }
++         int c2 = 'c2';
++                  ^~~~
++   { dg-end-multiline-output "" } */
++
++/* This line starts with <tabstop> spaces and has an internal tab after
++   a space.  */
++        int c3 =       'c3'; /* { dg-warning "24: multi-character character constant" } */
++/* { dg-begin-multiline-output "" }
++         int c3 =        'c3';
++                         ^~~~
++   { dg-end-multiline-output "" } */
+diff --git a/gcc/testsuite/c-c++-common/diagnostic-units-6.c b/gcc/testsuite/c-c++-common/diagnostic-units-6.c
+--- a/gcc/testsuite/c-c++-common/diagnostic-units-6.c   1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/diagnostic-units-6.c   2021-12-25 01:20:53.491636427 -0800
+@@ -0,0 +1,28 @@
++/* { dg-do compile } */
++/* { dg-additional-options "-fdiagnostics-column-unit=byte -fshow-column -fdiagnostics-show-caret -fdiagnostics-column-origin=100 -Wmultichar" } */
++
++/* column units: bytes (via arg)
++   column origin: 100 (via arg)
++   tabstop: 8 (via default) */
++
++/* This line starts with a tab.  */
++       int c1 = 'c1'; /* { dg-warning "110: multi-character character constant" } */
++/* { dg-begin-multiline-output "" }
++         int c1 = 'c1';
++                  ^~~~
++   { dg-end-multiline-output "" } */
++
++/* This line starts with <tabstop> spaces.  */
++        int c2 = 'c2'; /* { dg-warning "117: multi-character character constant" } */
++/* { dg-begin-multiline-output "" }
++         int c2 = 'c2';
++                  ^~~~
++   { dg-end-multiline-output "" } */
++
++/* This line starts with <tabstop> spaces and has an internal tab after
++   a space.  */
++        int c3 =       'c3'; /* { dg-warning "118: multi-character character constant" } */
++/* { dg-begin-multiline-output "" }
++         int c3 =        'c3';
++                         ^~~~
++   { dg-end-multiline-output "" } */
+diff --git a/gcc/testsuite/c-c++-common/diagnostic-units-7.c b/gcc/testsuite/c-c++-common/diagnostic-units-7.c
+--- a/gcc/testsuite/c-c++-common/diagnostic-units-7.c   1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/diagnostic-units-7.c   2021-12-25 01:20:53.491636427 -0800
+@@ -0,0 +1,28 @@
++/* { dg-do compile } */
++/* { dg-additional-options "-fdiagnostics-column-unit=byte -fshow-column -fdiagnostics-show-caret -ftabstop=9 -Wmultichar" } */
++
++/* column units: bytes (via arg)
++   column origin: 1 (via default)
++   tabstop: 9 (via arg) */
++
++/* This line starts with a tab.  */
++       int c1 = 'c1'; /* { dg-warning "11: multi-character character constant" } */
++/* { dg-begin-multiline-output "" }
++          int c1 = 'c1';
++                   ^~~~
++   { dg-end-multiline-output "" } */
++
++/* This line starts with <tabstop> spaces.  */
++         int c2 = 'c2'; /* { dg-warning "19: multi-character character constant" } */
++/* { dg-begin-multiline-output "" }
++          int c2 = 'c2';
++                   ^~~~
++   { dg-end-multiline-output "" } */
++
++/* This line starts with <tabstop> spaces and has an internal tab after
++   a space.  */
++         int c3 =      'c3'; /* { dg-warning "20: multi-character character constant" } */
++/* { dg-begin-multiline-output "" }
++          int c3 =          'c3';
++                            ^~~~
++   { dg-end-multiline-output "" } */
+diff --git a/gcc/testsuite/c-c++-common/diagnostic-units-8.c b/gcc/testsuite/c-c++-common/diagnostic-units-8.c
+--- a/gcc/testsuite/c-c++-common/diagnostic-units-8.c   1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/diagnostic-units-8.c   2021-12-25 01:20:53.491636427 -0800
+@@ -0,0 +1,28 @@
++/* { dg-do compile } */
++/* { dg-additional-options "-fshow-column -fdiagnostics-show-caret -ftabstop=9 -Wmultichar" } */
++
++/* column units: display (via default)
++   column origin: 1 (via default)
++   tabstop: 9 (via arg) */
++
++/* This line starts with a tab.  */
++       int c1 = 'c1'; /* { dg-warning "19: multi-character character constant" } */
++/* { dg-begin-multiline-output "" }
++          int c1 = 'c1';
++                   ^~~~
++   { dg-end-multiline-output "" } */
++
++/* This line starts with <tabstop> spaces.  */
++         int c2 = 'c2'; /* { dg-warning "19: multi-character character constant" } */
++/* { dg-begin-multiline-output "" }
++          int c2 = 'c2';
++                   ^~~~
++   { dg-end-multiline-output "" } */
++
++/* This line starts with <tabstop> spaces and has an internal tab after
++   a space.  */
++         int c3 =      'c3'; /* { dg-warning "28: multi-character character constant" } */
++/* { dg-begin-multiline-output "" }
++          int c3 =          'c3';
++                            ^~~~
++   { dg-end-multiline-output "" } */
+diff --git a/gcc/testsuite/c-c++-common/missing-close-symbol.c b/gcc/testsuite/c-c++-common/missing-close-symbol.c
+--- a/gcc/testsuite/c-c++-common/missing-close-symbol.c 2020-07-22 23:35:17.912390810 -0700
++++ b/gcc/testsuite/c-c++-common/missing-close-symbol.c 2021-12-25 01:20:53.491636427 -0800
+@@ -24,9 +24,9 @@ void test_static_assert_different_line (
+   _Static_assert(sizeof(int) >= sizeof(char), /* { dg-message "to match this '\\('" } */
+                 "msg"; /* { dg-error "expected '\\)' before ';' token" } */
+   /* { dg-begin-multiline-output "" }
+-    "msg";
+-         ^
+-         )
++                  "msg";
++                       ^
++                       )
+      { dg-end-multiline-output "" } */
+   /* { dg-begin-multiline-output "" }
+    _Static_assert(sizeof(int) >= sizeof(char),
+diff --git a/gcc/testsuite/c-c++-common/Wmisleading-indentation-3.c b/gcc/testsuite/c-c++-common/Wmisleading-indentation-3.c
+--- a/gcc/testsuite/c-c++-common/Wmisleading-indentation-3.c    2020-07-22 23:35:17.904390722 -0700
++++ b/gcc/testsuite/c-c++-common/Wmisleading-indentation-3.c    2021-12-25 01:20:53.487636494 -0800
+@@ -36,20 +36,20 @@ int fn_6 (int a, int b, int c)
+        /* ... */
+        if ((err = foo (a)) != 0)
+                goto fail;
+-       if ((err = foo (b)) != 0) /* { dg-message "2: this 'if' clause does not guard..." } */
++       if ((err = foo (b)) != 0) /* { dg-message "9: this 'if' clause does not guard..." } */
+                goto fail;
+-               goto fail; /* { dg-message "3: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'" } */
++               goto fail; /* { dg-message "17: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'" } */
+        if ((err = foo (c)) != 0)
+                goto fail;
+        /* ... */
+ 
+ /* { dg-begin-multiline-output "" }
+-  if ((err = foo (b)) != 0)
+-  ^~
++         if ((err = foo (b)) != 0)
++         ^~
+    { dg-end-multiline-output "" } */
+ /* { dg-begin-multiline-output "" }
+-   goto fail;
+-   ^~~~
++                 goto fail;
++                 ^~~~
+    { dg-end-multiline-output "" } */
+ 
+ fail:
+diff --git a/gcc/testsuite/c-c++-common/Wmisleading-indentation.c b/gcc/testsuite/c-c++-common/Wmisleading-indentation.c
+--- a/gcc/testsuite/c-c++-common/Wmisleading-indentation.c      2020-07-22 23:35:17.904390722 -0700
++++ b/gcc/testsuite/c-c++-common/Wmisleading-indentation.c      2021-12-25 01:20:53.487636494 -0800
+@@ -65,9 +65,9 @@ int fn_6 (int a, int b, int c)
+        /* ... */
+        if ((err = foo (a)) != 0)
+                goto fail;
+-       if ((err = foo (b)) != 0) /* { dg-message "2: this 'if' clause does not guard..." } */
++       if ((err = foo (b)) != 0) /* { dg-message "9: this 'if' clause does not guard..." } */
+                goto fail;
+-               goto fail; /* { dg-message "3: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'" } */
++               goto fail; /* { dg-message "17: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'" } */
+        if ((err = foo (c)) != 0)
+                goto fail;
+        /* ... */
+@@ -178,7 +178,7 @@ void fn_16_tabs (void)
+     while (flagA)
+       if (flagB) /* { dg-message "7: this 'if' clause does not guard..." } */
+        foo (0);
+-       foo (1);/* { dg-message "2: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'" } */
++       foo (1);/* { dg-message "9: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'" } */
+ }
+ 
+ void fn_17_spaces (void)
+diff --git a/gcc/testsuite/gcc.dg/analyzer/malloc-paths-9.c b/gcc/testsuite/gcc.dg/analyzer/malloc-paths-9.c
+--- a/gcc/testsuite/gcc.dg/analyzer/malloc-paths-9.c    2020-07-22 23:35:18.124393144 -0700
++++ b/gcc/testsuite/gcc.dg/analyzer/malloc-paths-9.c    2021-12-25 01:20:53.491636427 -0800
+@@ -288,7 +288,7 @@ int test_3 (int x, int y)
+     |      |     ~~~~~~~~~~
+     |      |     |
+     |      |     (4) ...to here
+-    |   NN |      to dereference it above
++    |   NN |                    to dereference it above
+     |   NN |   return *ptr;
+     |      |          ~~~~
+     |      |          |
+diff --git a/gcc/testsuite/gcc.dg/bad-binary-ops.c b/gcc/testsuite/gcc.dg/bad-binary-ops.c
+--- a/gcc/testsuite/gcc.dg/bad-binary-ops.c     2020-07-22 23:35:18.128393190 -0700
++++ b/gcc/testsuite/gcc.dg/bad-binary-ops.c     2021-12-25 01:20:53.491636427 -0800
+@@ -35,10 +35,10 @@ int test_2 (void)
+            ~~~~~~~~~~~~~~~~
+            |
+            struct s
+-    + some_other_function ());
+-    ^ ~~~~~~~~~~~~~~~~~~~~~~
+-      |
+-      struct t
++           + some_other_function ());
++           ^ ~~~~~~~~~~~~~~~~~~~~~~
++             |
++             struct t
+    { dg-end-multiline-output "" } */
+ }
+ 
+diff --git a/gcc/testsuite/gcc.dg/format/branch-1.c b/gcc/testsuite/gcc.dg/format/branch-1.c
+--- a/gcc/testsuite/gcc.dg/format/branch-1.c    2020-07-22 23:35:18.152393454 -0700
++++ b/gcc/testsuite/gcc.dg/format/branch-1.c    2021-12-25 01:20:53.491636427 -0800
+@@ -10,7 +10,7 @@ foo (long l, int nfoo)
+ {
+   printf ((nfoo > 1) ? "%d foos" : "%d foo", nfoo);
+   printf ((l > 1) ? "%d foos" /* { dg-warning "23:int" "wrong type in conditional expr" } */
+-                 : "%d foo", l); /* { dg-warning "16:int" "wrong type in conditional expr" } */
++                 : "%d foo", l); /* { dg-warning "23:int" "wrong type in conditional expr" } */
+   printf ((l > 1) ? "%ld foos" : "%d foo", l); /* { dg-warning "36:int" "wrong type in conditional expr" } */
+   printf ((l > 1) ? "%d foos" : "%ld foo", l); /* { dg-warning "23:int" "wrong type in conditional expr" } */
+   /* Should allow one case to have extra arguments.  */
+diff --git a/gcc/testsuite/gcc.dg/format/pr79210.c b/gcc/testsuite/gcc.dg/format/pr79210.c
+--- a/gcc/testsuite/gcc.dg/format/pr79210.c     2020-07-22 23:35:18.152393454 -0700
++++ b/gcc/testsuite/gcc.dg/format/pr79210.c     2021-12-25 01:20:53.491636427 -0800
+@@ -20,4 +20,4 @@ LPFC_VPORT_ATTR_R(peer_port_login,
+                  "Allow peer ports on the same physical port to login to each "
+                  "other.");
+ 
+-/* { dg-warning "6: format .%d. expects argument of type .int., but argument 4 has type .unsigned int. " "" { target *-*-* } .-12 } */
++/* { dg-warning "20: format .%d. expects argument of type .int., but argument 4 has type .unsigned int. " "" { target *-*-* } .-12 } */
+diff --git a/gcc/testsuite/gcc.dg/plugin/diagnostic-test-expressions-1.c b/gcc/testsuite/gcc.dg/plugin/diagnostic-test-expressions-1.c
+--- a/gcc/testsuite/gcc.dg/plugin/diagnostic-test-expressions-1.c       2020-07-22 23:35:18.172393674 -0700
++++ b/gcc/testsuite/gcc.dg/plugin/diagnostic-test-expressions-1.c       2021-12-25 01:20:53.491636427 -0800
+@@ -540,15 +540,15 @@ void test_builtin_types_compatible_p (un
+   __emit_expression_range (0,
+                           f (i) + __builtin_types_compatible_p (long, int)); /* { dg-warning "range" } */
+ /* { dg-begin-multiline-output "" }
+-       f (i) + __builtin_types_compatible_p (long, int));
+-       ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
++                            f (i) + __builtin_types_compatible_p (long, int));
++                            ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+    { dg-end-multiline-output "" } */
+ 
+   __emit_expression_range (0,
+                           __builtin_types_compatible_p (long, int) + f (i)); /* { dg-warning "range" } */
+ /* { dg-begin-multiline-output "" }
+-       __builtin_types_compatible_p (long, int) + f (i));
+-       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~
++                            __builtin_types_compatible_p (long, int) + f (i));
++                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~
+    { dg-end-multiline-output "" } */
+ }
+ 
+@@ -671,8 +671,8 @@ void test_multiple_ordinary_maps (void)
+ /* { dg-begin-multiline-output "" }
+    __emit_expression_range (0, foo (0,
+                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+-        "0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789"));
+-        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
++                                    "0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789"));
++                                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+    { dg-end-multiline-output "" } */
+ 
+   /* Another expression that transitions between ordinary maps; this
+@@ -685,8 +685,8 @@ void test_multiple_ordinary_maps (void)
+ /* { dg-begin-multiline-output "" }
+    __emit_expression_range (0, foo (0, "01234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789",
+                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+-        0));
+-        ~~                      
++                                    0));
++                                    ~~
+    { dg-end-multiline-output "" } */
+ }
+ 
+diff --git a/gcc/testsuite/gcc.dg/plugin/diagnostic-test-string-literals-1.c b/gcc/testsuite/gcc.dg/plugin/diagnostic-test-string-literals-1.c
+--- a/gcc/testsuite/gcc.dg/plugin/diagnostic-test-string-literals-1.c   2020-07-22 23:35:18.172393674 -0700
++++ b/gcc/testsuite/gcc.dg/plugin/diagnostic-test-string-literals-1.c   2021-12-25 01:20:53.491636427 -0800
+@@ -335,11 +335,11 @@ pr87652 (const char *stem, int counter)
+ /* { dg-error "unable to read substring location: unable to read source line" "" { target c } 329 } */
+ /* { dg-error "unable to read substring location: failed to get ordinary maps" "" { target c++ } 329 } */
+ /* { dg-begin-multiline-output "" }
+-     __emit_string_literal_range(__FILE__":%5d: " format, \
++     __emit_string_literal_range(__FILE__":%5d: " format,        \
+                                  ^~~~~~~~
+      { dg-end-multiline-output "" { target c } } */
+ /* { dg-begin-multiline-output "" }
+-     __emit_string_literal_range(__FILE__":%5d: " format, \
++     __emit_string_literal_range(__FILE__":%5d: " format,        \
+                                  ^
+      { dg-end-multiline-output "" { target c++ } } */
+ 
+diff --git a/gcc/testsuite/gcc.dg/redecl-4.c b/gcc/testsuite/gcc.dg/redecl-4.c
+--- a/gcc/testsuite/gcc.dg/redecl-4.c   2020-07-22 23:35:18.192393895 -0700
++++ b/gcc/testsuite/gcc.dg/redecl-4.c   2021-12-25 01:20:53.491636427 -0800
+@@ -15,7 +15,7 @@ f (void)
+     /* Should get format warnings even though the built-in declaration
+        isn't "visible".  */
+     printf (
+-           "%s", 1); /* { dg-warning "8:format" } */
++           "%s", 1); /* { dg-warning "15:format" } */
+     /* The type of strcmp here should have no prototype.  */
+     if (0)
+       strcmp (1);
+diff --git a/gcc/testsuite/g++.dg/diagnostic/bad-binary-ops.C b/gcc/testsuite/g++.dg/diagnostic/bad-binary-ops.C
+--- a/gcc/testsuite/g++.dg/diagnostic/bad-binary-ops.C  2020-07-22 23:35:17.972391472 -0700
++++ b/gcc/testsuite/g++.dg/diagnostic/bad-binary-ops.C  2021-12-25 01:20:53.491636427 -0800
+@@ -33,10 +33,10 @@ int test_2 (void)
+            ~~~~~~~~~~~~~~~~
+                          |
+                          s
+-    + some_other_function ());
+-    ^ ~~~~~~~~~~~~~~~~~~~~~~
+-                          |
+-                          t
++           + some_other_function ());
++           ^ ~~~~~~~~~~~~~~~~~~~~~~
++                                 |
++                                 t
+    { dg-end-multiline-output "" } */
+ }
+ 
+diff --git a/gcc/testsuite/g++.dg/parse/error4.C b/gcc/testsuite/g++.dg/parse/error4.C
+--- a/gcc/testsuite/g++.dg/parse/error4.C       2020-07-22 23:35:18.012391910 -0700
++++ b/gcc/testsuite/g++.dg/parse/error4.C       2021-12-25 01:20:53.491636427 -0800
+@@ -7,4 +7,4 @@ struct X {
+                 int);
+ };
+ 
+-// { dg-error "4:'itn' has not been declared" "" { target *-*-* } 6 }
++// { dg-error "18:'itn' has not been declared" "" { target *-*-* } 6 }
+diff --git a/gcc/testsuite/gfortran.dg/diagnostic-format-json-1.F90 b/gcc/testsuite/gfortran.dg/diagnostic-format-json-1.F90
+--- a/gcc/testsuite/gfortran.dg/diagnostic-format-json-1.F90    2020-07-22 23:35:18.512397420 -0700
++++ b/gcc/testsuite/gfortran.dg/diagnostic-format-json-1.F90    2021-12-25 01:20:53.491636427 -0800
+@@ -8,17 +8,22 @@
+ ! We can't rely on any ordering of the keys.
+ 
+ ! { dg-regexp "\"kind\": \"error\"" }
++! { dg-regexp "\"column-origin\": 1" }
+ ! { dg-regexp "\"message\": \"#error message\"" }
+ 
+ ! { dg-regexp "\"caret\": \{" }
+ ! { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-1.F90\"" }
+ ! { dg-regexp "\"line\": 4" }
+ ! { dg-regexp "\"column\": 2" }
++! { dg-regexp "\"display-column\": 2" }
++! { dg-regexp "\"byte-column\": 2" }
+ 
+ ! { dg-regexp "\"finish\": \{" }
+ ! { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-1.F90\"" }
+ ! { dg-regexp "\"line\": 4" }
+ ! { dg-regexp "\"column\": 6" }
++! { dg-regexp "\"display-column\": 6" }
++! { dg-regexp "\"byte-column\": 6" }
+ 
+ ! { dg-regexp "\"locations\": \[\[\{\}, \]*\]" }
+ ! { dg-regexp "\"children\": \[\[\]\[\]\]" }
+diff --git a/gcc/testsuite/gfortran.dg/diagnostic-format-json-2.F90 b/gcc/testsuite/gfortran.dg/diagnostic-format-json-2.F90
+--- a/gcc/testsuite/gfortran.dg/diagnostic-format-json-2.F90    2020-07-22 23:35:18.512397420 -0700
++++ b/gcc/testsuite/gfortran.dg/diagnostic-format-json-2.F90    2021-12-25 01:20:53.491636427 -0800
+@@ -8,6 +8,7 @@
+ ! We can't rely on any ordering of the keys. 
+ 
+ ! { dg-regexp "\"kind\": \"warning\"" }
++! { dg-regexp "\"column-origin\": 1" }
+ ! { dg-regexp "\"message\": \"#warning message\"" }
+ ! { dg-regexp "\"option\": \"-Wcpp\"" }
+ ! { dg-regexp "\"option_url\": \"\[^\n\r\"\]*#index-Wcpp\"" }
+@@ -16,11 +17,15 @@
+ ! { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-2.F90\"" }
+ ! { dg-regexp "\"line\": 4" }
+ ! { dg-regexp "\"column\": 2" }
++! { dg-regexp "\"display-column\": 2" }
++! { dg-regexp "\"byte-column\": 2" }
+ 
+ ! { dg-regexp "\"finish\": \{" }
+ ! { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-2.F90\"" }
+ ! { dg-regexp "\"line\": 4" }
+ ! { dg-regexp "\"column\": 8" }
++! { dg-regexp "\"display-column\": 8" }
++! { dg-regexp "\"byte-column\": 8" }
+ 
+ ! { dg-regexp "\"locations\": \[\[\{\}, \]*\]" }
+ ! { dg-regexp "\"children\": \[\[\]\[\]\]" }
+diff --git a/gcc/testsuite/gfortran.dg/diagnostic-format-json-3.F90 b/gcc/testsuite/gfortran.dg/diagnostic-format-json-3.F90
+--- a/gcc/testsuite/gfortran.dg/diagnostic-format-json-3.F90    2020-07-22 23:35:18.512397420 -0700
++++ b/gcc/testsuite/gfortran.dg/diagnostic-format-json-3.F90    2021-12-25 01:20:53.491636427 -0800
+@@ -8,6 +8,7 @@
+ ! We can't rely on any ordering of the keys.
+ 
+ ! { dg-regexp "\"kind\": \"error\"" }
++! { dg-regexp "\"column-origin\": 1" }
+ ! { dg-regexp "\"message\": \"#warning message\"" }
+ ! { dg-regexp "\"option\": \"-Werror=cpp\"" }
+ ! { dg-regexp "\"option_url\": \"\[^\n\r\"\]*#index-Wcpp\"" }
+@@ -16,11 +17,15 @@
+ ! { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-3.F90\"" }
+ ! { dg-regexp "\"line\": 4" }
+ ! { dg-regexp "\"column\": 2" }
++! { dg-regexp "\"display-column\": 2" }
++! { dg-regexp "\"byte-column\": 2" }
+ 
+ ! { dg-regexp "\"finish\": \{" }
+ ! { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-3.F90\"" }
+ ! { dg-regexp "\"line\": 4" }
+ ! { dg-regexp "\"column\": 8" }
++! { dg-regexp "\"display-column\": 8" }
++! { dg-regexp "\"byte-column\": 8" }
+ 
+ ! { dg-regexp "\"locations\": \[\[\{\}, \]*\]" }
+ ! { dg-regexp "\"children\": \[\[\]\[\]\]" }
+diff --git a/gcc/testsuite/go.dg/arrayclear.go b/gcc/testsuite/go.dg/arrayclear.go
+--- a/gcc/testsuite/go.dg/arrayclear.go 2020-07-22 23:35:18.588398257 -0700
++++ b/gcc/testsuite/go.dg/arrayclear.go 2021-12-25 01:20:53.491636427 -0800
+@@ -1,5 +1,8 @@
+ // { dg-do compile }
+ // { dg-options "-fgo-debug-optimization" }
++// This comment is necessary to work around a dejagnu bug. Otherwise, the
++// column of the second error message would equal the row of the first one, and
++// since the errors are also identical, dejagnu is not able to distinguish them.
+ 
+ package p
+ 
+diff --git a/gcc/testsuite/g++.old-deja/g++.brendan/crash11.C b/gcc/testsuite/g++.old-deja/g++.brendan/crash11.C
+--- a/gcc/testsuite/g++.old-deja/g++.brendan/crash11.C  2020-07-22 23:35:18.048392308 -0700
++++ b/gcc/testsuite/g++.old-deja/g++.brendan/crash11.C  2021-12-25 01:20:53.491636427 -0800
+@@ -9,13 +9,13 @@ class A {
+        int     h;
+        A() { i=10; j=20; }
+        virtual void f1() { printf("i=%d j=%d\n",i,j); }
+-       friend virtual void f2() { printf("i=%d j=%d\n",i,j); } // { dg-error "9:virtual functions cannot be friends" }
++       friend virtual void f2() { printf("i=%d j=%d\n",i,j); } // { dg-error "16:virtual functions cannot be friends" }
+ };
+ 
+ class B : public A {
+     public:
+        virtual void f1() { printf("i=%d j=%d\n",i,j); }// { dg-error "" }  member.*// ERROR -  member.*
+-       friend virtual void f2() { printf("i=%d j=%d\n",i,j); }  // { dg-error "9:virtual functions cannot be friends" }
++       friend virtual void f2() { printf("i=%d j=%d\n",i,j); }  // { dg-error "16:virtual functions cannot be friends" }
+ // { dg-error "private" "" { target *-*-* } .-1 }
+ };
+ 
+diff --git a/gcc/testsuite/g++.old-deja/g++.pt/overload2.C b/gcc/testsuite/g++.old-deja/g++.pt/overload2.C
+--- a/gcc/testsuite/g++.old-deja/g++.pt/overload2.C     2020-07-22 23:35:18.072392572 -0700
++++ b/gcc/testsuite/g++.old-deja/g++.pt/overload2.C     2021-12-25 01:20:53.491636427 -0800
+@@ -12,5 +12,5 @@ int
+ main()
+ {
+        C<char*>        c;
+-       char*           p = Z(c.O); //{ dg-error "13:'Z' was not declared" } ambiguous c.O
++       char*           p = Z(c.O); //{ dg-error "29:'Z' was not declared" } ambiguous c.O
+ }
+diff --git a/gcc/testsuite/g++.old-deja/g++.robertl/eb109.C b/gcc/testsuite/g++.old-deja/g++.robertl/eb109.C
+--- a/gcc/testsuite/g++.old-deja/g++.robertl/eb109.C    2020-07-22 23:35:18.076392617 -0700
++++ b/gcc/testsuite/g++.old-deja/g++.robertl/eb109.C    2021-12-25 01:20:53.491636427 -0800
+@@ -48,8 +48,8 @@ ostream& operator<<(ostream& os, Graph<V
+ 
+         // The compiler does not like this line!!!!!!
+         typename Graph<VertexType, EdgeType>::Successor::iterator
+-         startN = G[i].second.begin(), // { dg-error "14:no match" } no index operator
+-         endN   = G[i].second.end();  // { dg-error "14:no match" } no index operator
++         startN = G[i].second.begin(), // { dg-error "21:no match" } no index operator
++         endN   = G[i].second.end();  // { dg-error "21:no match" } no index operator
+ 
+         while(startN != endN)
+         {
+diff --git a/gcc/tree-diagnostic-path.cc b/gcc/tree-diagnostic-path.cc
+--- a/gcc/tree-diagnostic-path.cc       2020-07-22 23:35:18.628398698 -0700
++++ b/gcc/tree-diagnostic-path.cc       2021-12-25 01:20:53.491636427 -0800
+@@ -493,7 +493,7 @@ default_tree_diagnostic_path_printer (di
+    doesn't have access to trees (for m_fndecl).  */
+ 
+ json::value *
+-default_tree_make_json_for_path (diagnostic_context *,
++default_tree_make_json_for_path (diagnostic_context *context,
+                                 const diagnostic_path *path)
+ {
+   json::array *path_array = new json::array ();
+@@ -504,7 +504,8 @@ default_tree_make_json_for_path (diagnos
+       json::object *event_obj = new json::object ();
+       if (event.get_location ())
+        event_obj->set ("location",
+-                       json_from_expanded_location (event.get_location ()));
++                       json_from_expanded_location (context,
++                                                    event.get_location ()));
+       label_text event_text (event.get_desc (false));
+       event_obj->set ("description", new json::string (event_text.m_buffer));
+       event_text.maybe_free ();
+diff --git a/libcpp/charset.c b/libcpp/charset.c
+--- a/libcpp/charset.c  2020-07-22 23:35:18.712399623 -0700
++++ b/libcpp/charset.c  2021-12-25 01:20:53.491636427 -0800
+@@ -2276,49 +2276,90 @@ cpp_string_location_reader::get_next ()
+   return result;
+ }
+ 
+-/* Helper for cpp_byte_column_to_display_column and its inverse.  Given a
+-   pointer to a UTF-8-encoded character, compute its display width.  *INBUFP
+-   points on entry to the start of the UTF-8 encoding of the character, and
+-   is updated to point just after the last byte of the encoding.  *INBYTESLEFTP
+-   contains on entry the remaining size of the buffer into which *INBUFP
+-   points, and this is also updated accordingly.  If *INBUFP does not
++cpp_display_width_computation::
++cpp_display_width_computation (const char *data, int data_length, int tabstop) :
++  m_begin (data),
++  m_next (m_begin),
++  m_bytes_left (data_length),
++  m_tabstop (tabstop),
++  m_display_cols (0)
++{
++  gcc_assert (m_tabstop > 0);
++}
++
++
++/* The main implementation function for class cpp_display_width_computation.
++   m_next points on entry to the start of the UTF-8 encoding of the next
++   character, and is updated to point just after the last byte of the encoding.
++   m_bytes_left contains on entry the remaining size of the buffer into which
++   m_next points, and this is also updated accordingly.  If m_next does not
+    point to a valid UTF-8-encoded sequence, then it will be treated as a single
+-   byte with display width 1.  */
++   byte with display width 1.  m_cur_display_col is the current display column,
++   relative to which tab stops should be expanded.  Returns the display width of
++   the codepoint just processed.  */
+ 
+-static inline int
+-compute_next_display_width (const uchar **inbufp, size_t *inbytesleftp)
++int
++cpp_display_width_computation::process_next_codepoint ()
+ {
+   cppchar_t c;
+-  if (one_utf8_to_cppchar (inbufp, inbytesleftp, &c) != 0)
++  int next_width;
++
++  if (*m_next == '\t')
++    {
++      ++m_next;
++      --m_bytes_left;
++      next_width = m_tabstop - (m_display_cols % m_tabstop);
++    }
++  else if (one_utf8_to_cppchar ((const uchar **) &m_next, &m_bytes_left, &c)
++          != 0)
+     {
+       /* Input is not convertible to UTF-8.  This could be fine, e.g. in a
+         string literal, so don't complain.  Just treat it as if it has a width
+         of one.  */
+-      ++*inbufp;
+-      --*inbytesleftp;
+-      return 1;
++      ++m_next;
++      --m_bytes_left;
++      next_width = 1;
++    }
++  else
++    {
++      /*  one_utf8_to_cppchar() has updated m_next and m_bytes_left for us.  */
++      next_width = cpp_wcwidth (c);
+     }
+ 
+-  /*  one_utf8_to_cppchar() has updated inbufp and inbytesleftp for us.  */
+-  return cpp_wcwidth (c);
++  m_display_cols += next_width;
++  return next_width;
++}
++
++/*  Utility to advance the byte stream by the minimum amount needed to consume
++    N display columns.  Returns the number of display columns that were
++    actually skipped.  This could be less than N, if there was not enough data,
++    or more than N, if the last character to be skipped had a sufficiently large
++    display width.  */
++int
++cpp_display_width_computation::advance_display_cols (int n)
++{
++  const int start = m_display_cols;
++  const int target = start + n;
++  while (m_display_cols < target && !done ())
++    process_next_codepoint ();
++  return m_display_cols - start;
+ }
+ 
+ /*  For the string of length DATA_LENGTH bytes that begins at DATA, compute
+     how many display columns are occupied by the first COLUMN bytes.  COLUMN
+     may exceed DATA_LENGTH, in which case the phantom bytes at the end are
+-    treated as if they have display width 1.  */
++    treated as if they have display width 1.  Tabs are expanded to the next tab
++    stop, relative to the start of DATA.  */
+ 
+ int
+ cpp_byte_column_to_display_column (const char *data, int data_length,
+-                                  int column)
++                                  int column, int tabstop)
+ {
+-  int display_col = 0;
+-  const uchar *udata = (const uchar *) data;
+   const int offset = MAX (0, column - data_length);
+-  size_t inbytesleft = column - offset;
+-  while (inbytesleft)
+-    display_col += compute_next_display_width (&udata, &inbytesleft);
+-  return display_col + offset;
++  cpp_display_width_computation dw (data, column - offset, tabstop);
++  while (!dw.done ())
++    dw.process_next_codepoint ();
++  return dw.display_cols_processed () + offset;
+ }
+ 
+ /*  For the string of length DATA_LENGTH bytes that begins at DATA, compute
+@@ -2328,14 +2369,11 @@ cpp_byte_column_to_display_column (const
+ 
+ int
+ cpp_display_column_to_byte_column (const char *data, int data_length,
+-                                  int display_col)
++                                  int display_col, int tabstop)
+ {
+-  int column = 0;
+-  const uchar *udata = (const uchar *) data;
+-  size_t inbytesleft = data_length;
+-  while (column < display_col && inbytesleft)
+-      column += compute_next_display_width (&udata, &inbytesleft);
+-  return data_length - inbytesleft + MAX (0, display_col - column);
++  cpp_display_width_computation dw (data, data_length, tabstop);
++  const int avail_display = dw.advance_display_cols (display_col);
++  return dw.bytes_processed () + MAX (0, display_col - avail_display);
+ }
+ 
+ /* Our own version of wcwidth().  We don't use the actual wcwidth() in glibc,
+diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h
+--- a/libcpp/include/cpplib.h   2020-07-22 23:35:18.712399623 -0700
++++ b/libcpp/include/cpplib.h   2021-12-25 01:20:53.491636427 -0800
+@@ -312,9 +312,6 @@ enum cpp_normalize_level {
+    carries all the options visible to the command line.  */
+ struct cpp_options
+ {
+-  /* Characters between tab stops.  */
+-  unsigned int tabstop;
+-
+   /* The language we're preprocessing.  */
+   enum c_lang lang;
+ 
+@@ -1322,14 +1319,43 @@ extern const char * cpp_get_userdef_suff
+   (const cpp_token *);
+ 
+ /* In charset.c */
++
++/* A class to manage the state while converting a UTF-8 sequence to cppchar_t
++   and computing the display width one character at a time.  */
++class cpp_display_width_computation {
++ public:
++  cpp_display_width_computation (const char *data, int data_length,
++                                int tabstop);
++  const char *next_byte () const { return m_next; }
++  int bytes_processed () const { return m_next - m_begin; }
++  int bytes_left () const { return m_bytes_left; }
++  bool done () const { return !bytes_left (); }
++  int display_cols_processed () const { return m_display_cols; }
++
++  int process_next_codepoint ();
++  int advance_display_cols (int n);
++
++ private:
++  const char *const m_begin;
++  const char *m_next;
++  size_t m_bytes_left;
++  const int m_tabstop;
++  int m_display_cols;
++};
++
++/* Convenience functions that are simple use cases for class
++   cpp_display_width_computation.  Tab characters will be expanded to spaces
++   as determined by TABSTOP.  */
+ int cpp_byte_column_to_display_column (const char *data, int data_length,
+-                                      int column);
+-inline int cpp_display_width (const char *data, int data_length)
++                                      int column, int tabstop);
++inline int cpp_display_width (const char *data, int data_length,
++                             int tabstop)
+ {
+-    return cpp_byte_column_to_display_column (data, data_length, data_length);
++  return cpp_byte_column_to_display_column (data, data_length, data_length,
++                                           tabstop);
+ }
+ int cpp_display_column_to_byte_column (const char *data, int data_length,
+-                                      int display_col);
++                                      int display_col, int tabstop);
+ int cpp_wcwidth (cppchar_t c);
+ 
+ #endif /* ! LIBCPP_CPPLIB_H */
+diff --git a/libcpp/init.c b/libcpp/init.c
+--- a/libcpp/init.c     2020-07-22 23:35:18.712399623 -0700
++++ b/libcpp/init.c     2021-12-25 01:20:53.491636427 -0800
+@@ -190,7 +190,6 @@ cpp_create_reader (enum c_lang lang, cpp
+   CPP_OPTION (pfile, discard_comments) = 1;
+   CPP_OPTION (pfile, discard_comments_in_macro_exp) = 1;
+   CPP_OPTION (pfile, max_include_depth) = 200;
+-  CPP_OPTION (pfile, tabstop) = 8;
+   CPP_OPTION (pfile, operator_names) = 1;
+   CPP_OPTION (pfile, warn_trigraphs) = 2;
+   CPP_OPTION (pfile, warn_endif_labels) = 1;
diff --git a/meta/recipes-devtools/gcc/gcc/0002-CVE-2021-42574.patch b/meta/recipes-devtools/gcc/gcc/0002-CVE-2021-42574.patch
new file mode 100644
index 0000000000..5b1896ed69
--- /dev/null
+++ b/meta/recipes-devtools/gcc/gcc/0002-CVE-2021-42574.patch
@@ -0,0 +1,2270 @@
+From bd5e882cf6e0def3dd1bc106075d59a303fe0d1e Mon Sep 17 00:00:00 2001
+From: David Malcolm <dmalcolm@redhat.com>
+Date: Mon, 18 Oct 2021 18:55:31 -0400
+Subject: [PATCH] diagnostics: escape non-ASCII source bytes for certain
+ diagnostics
+MIME-Version: 1.0
+Content-Type: text/plain; charset=utf8
+Content-Transfer-Encoding: 8bit
+
+This patch adds support to GCC's diagnostic subsystem for escaping certain
+bytes and Unicode characters when quoting source code.
+
+Specifically, this patch adds a new flag rich_location::m_escape_on_output
+which is a hint from a diagnostic that non-ASCII bytes in the pertinent
+lines of the user's source code should be escaped when printed.
+
+The patch sets this for the following diagnostics:
+- when complaining about stray bytes in the program (when these
+are non-printable)
+- when complaining about "null character(s) ignored");
+- for -Wnormalized= (and generate source ranges for such warnings)
+
+The escaping is controlled by a new option:
+  -fdiagnostics-escape-format=[unicode|bytes]
+
+For example, consider a diagnostic involing a source line containing the
+string "before" followed by the Unicode character U+03C0 ("GREEK SMALL
+LETTER PI", with UTF-8 encoding 0xCF 0x80) followed by the byte 0xBF
+(a stray UTF-8 trailing byte), followed by the string "after", where the
+diagnostic highlights the U+03C0 character.
+
+By default, this line will be printed verbatim to the user when
+reporting a diagnostic at it, as:
+
+ beforeÏXafter
+       ^
+
+(using X for the stray byte to avoid putting invalid UTF-8 in this
+commit message)
+
+If the diagnostic sets the "escape" flag, it will be printed as:
+
+ before<U+03C0><BF>after
+       ^~~~~~~~
+
+with -fdiagnostics-escape-format=unicode (the default), or as:
+
+  before<CF><80><BF>after
+        ^~~~~~~~
+
+if the user supplies -fdiagnostics-escape-format=bytes.
+
+This only affects how the source is printed; it does not affect
+how column numbers that are printed (as per -fdiagnostics-column-unit=
+and -fdiagnostics-column-origin=).
+
+gcc/c-family/ChangeLog:
+        * c-lex.c (c_lex_with_flags): When complaining about non-printable
+        CPP_OTHER tokens, set the "escape on output" flag.
+
+gcc/ChangeLog:
+        * common.opt (fdiagnostics-escape-format=): New.
+        (diagnostics_escape_format): New enum.
+        (DIAGNOSTICS_ESCAPE_FORMAT_UNICODE): New enum value.
+        (DIAGNOSTICS_ESCAPE_FORMAT_BYTES): Likewise.
+        * diagnostic-format-json.cc (json_end_diagnostic): Add
+        "escape-source" attribute.
+        * diagnostic-show-locus.c
+        (exploc_with_display_col::exploc_with_display_col): Replace
+        "tabstop" param with a cpp_char_column_policy and add an "aspect"
+        param.  Use these to compute m_display_col accordingly.
+        (struct char_display_policy): New struct.
+        (layout::m_policy): New field.
+        (layout::m_escape_on_output): New field.
+        (def_policy): New function.
+        (make_range): Update for changes to exploc_with_display_col ctor.
+        (default_print_decoded_ch): New.
+        (width_per_escaped_byte): New.
+        (escape_as_bytes_width): New.
+        (escape_as_bytes_print): New.
+        (escape_as_unicode_width): New.
+        (escape_as_unicode_print): New.
+        (make_policy): New.
+        (layout::layout): Initialize new fields.  Update m_exploc ctor
+        call for above change to ctor.
+        (layout::maybe_add_location_range): Update for changes to
+        exploc_with_display_col ctor.
+        (layout::calculate_x_offset_display): Update for change to
+        cpp_display_width.
+        (layout::print_source_line): Pass policy
+        to cpp_display_width_computation. Capture cpp_decoded_char when
+        calling process_next_codepoint.  Move printing of source code to
+        m_policy.m_print_cb.
+        (line_label::line_label): Pass in policy rather than context.
+        (layout::print_any_labels): Update for change to line_label ctor.
+        (get_affected_range): Pass in policy rather than context, updating
+        calls to location_compute_display_column accordingly.
+        (get_printed_columns): Likewise, also for cpp_display_width.
+        (correction::correction): Pass in policy rather than tabstop.
+        (correction::compute_display_cols): Pass m_policy rather than
+        m_tabstop to cpp_display_width.
+        (correction::m_tabstop): Replace with...
+        (correction::m_policy): ...this.
+        (line_corrections::line_corrections): Pass in policy rather than
+        context.
+        (line_corrections::m_context): Replace with...
+        (line_corrections::m_policy): ...this.
+        (line_corrections::add_hint): Update to use m_policy rather than
+        m_context.
+        (line_corrections::add_hint): Likewise.
+        (layout::print_trailing_fixits): Likewise.
+        (selftest::test_display_widths): New.
+        (selftest::test_layout_x_offset_display_utf8): Update to use
+        policy rather than tabstop.
+        (selftest::test_one_liner_labels_utf8): Add test of escaping
+        source lines.
+        (selftest::test_diagnostic_show_locus_one_liner_utf8): Update to
+        use policy rather than tabstop.
+        (selftest::test_overlapped_fixit_printing): Likewise.
+        (selftest::test_overlapped_fixit_printing_utf8): Likewise.
+        (selftest::test_overlapped_fixit_printing_2): Likewise.
+        (selftest::test_tab_expansion): Likewise.
+        (selftest::test_escaping_bytes_1): New.
+        (selftest::test_escaping_bytes_2): New.
+        (selftest::diagnostic_show_locus_c_tests): Call the new tests.
+        * diagnostic.c (diagnostic_initialize): Initialize
+        context->escape_format.
+        (convert_column_unit): Update to use default character width policy.
+        (selftest::test_diagnostic_get_location_text): Likewise.
+        * diagnostic.h (enum diagnostics_escape_format): New enum.
+        (diagnostic_context::escape_format): New field.
+        * doc/invoke.texi (-fdiagnostics-escape-format=): New option.
+        (-fdiagnostics-format=): Add "escape-source" attribute to examples
+        of JSON output, and document it.
+        * input.c (location_compute_display_column): Pass in "policy"
+        rather than "tabstop", passing to
+        cpp_byte_column_to_display_column.
+        (selftest::test_cpp_utf8): Update to use cpp_char_column_policy.
+        * input.h (class cpp_char_column_policy): New forward decl.
+        (location_compute_display_column): Pass in "policy" rather than
+        "tabstop".
+        * opts.c (common_handle_option): Handle
+        OPT_fdiagnostics_escape_format_.
+        * selftest.c (temp_source_file::temp_source_file): New ctor
+        overload taking a size_t.
+        * selftest.h (temp_source_file::temp_source_file): Likewise.
+
+gcc/testsuite/ChangeLog:
+        * c-c++-common/diagnostic-format-json-1.c: Add regexp to consume
+        "escape-source" attribute.
+        * c-c++-common/diagnostic-format-json-2.c: Likewise.
+        * c-c++-common/diagnostic-format-json-3.c: Likewise.
+        * c-c++-common/diagnostic-format-json-4.c: Likewise, twice.
+        * c-c++-common/diagnostic-format-json-5.c: Likewise.
+        * gcc.dg/cpp/warn-normalized-4-bytes.c: New test.
+        * gcc.dg/cpp/warn-normalized-4-unicode.c: New test.
+        * gcc.dg/encoding-issues-bytes.c: New test.
+        * gcc.dg/encoding-issues-unicode.c: New test.
+        * gfortran.dg/diagnostic-format-json-1.F90: Add regexp to consume
+        "escape-source" attribute.
+        * gfortran.dg/diagnostic-format-json-2.F90: Likewise.
+        * gfortran.dg/diagnostic-format-json-3.F90: Likewise.
+
+libcpp/ChangeLog:
+        * charset.c (convert_escape): Use encoding_rich_location when
+        complaining about nonprintable unknown escape sequences.
+        (cpp_display_width_computation::::cpp_display_width_computation):
+        Pass in policy rather than tabstop.
+        (cpp_display_width_computation::process_next_codepoint): Add "out"
+        param and populate *out if non-NULL.
+        (cpp_display_width_computation::advance_display_cols): Pass NULL
+        to process_next_codepoint.
+        (cpp_byte_column_to_display_column): Pass in policy rather than
+        tabstop.  Pass NULL to process_next_codepoint.
+        (cpp_display_column_to_byte_column): Pass in policy rather than
+        tabstop.
+        * errors.c (cpp_diagnostic_get_current_location): New function,
+        splitting out the logic from...
+        (cpp_diagnostic): ...here.
+        (cpp_warning_at): New function.
+        (cpp_pedwarning_at): New function.
+        * include/cpplib.h (cpp_warning_at): New decl for rich_location.
+        (cpp_pedwarning_at): Likewise.
+        (struct cpp_decoded_char): New.
+        (struct cpp_char_column_policy): New.
+        (cpp_display_width_computation::cpp_display_width_computation):
+        Replace "tabstop" param with "policy".
+        (cpp_display_width_computation::process_next_codepoint): Add "out"
+        param.
+        (cpp_display_width_computation::m_tabstop): Replace with...
+        (cpp_display_width_computation::m_policy): ...this.
+        (cpp_byte_column_to_display_column): Replace "tabstop" param with
+        "policy".
+        (cpp_display_width): Likewise.
+        (cpp_display_column_to_byte_column): Likewise.
+        * include/line-map.h (rich_location::escape_on_output_p): New.
+        (rich_location::set_escape_on_output): New.
+        (rich_location::m_escape_on_output): New.
+        * internal.h (cpp_diagnostic_get_current_location): New decl.
+        (class encoding_rich_location): New.
+        * lex.c (skip_whitespace): Use encoding_rich_location when
+        complaining about null characters.
+        (warn_about_normalization): Generate a source range when
+        complaining about improperly normalized tokens, rather than just a
+        point, and use encoding_rich_location so that the source code
+        is escaped on printing.
+        * line-map.c (rich_location::rich_location): Initialize
+        m_escape_on_output.
+
+Signed-off-by: David Malcolm <dmalcolm@redhat.com>
+
+CVE: CVE-2021-42574
+Upstream-Status: Backport [https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=bd5e882cf6e0def3dd1bc106075d59a303fe0d1e]
+Signed-off-by: Pgowda <pgowda.cve@gmail.com>
+
+---
+ gcc/c-family/c-lex.c                          |   6 +-
+ gcc/common.opt                                |  13 +
+ gcc/diagnostic-format-json.cc                 |   3 +
+ gcc/diagnostic-show-locus.c                   | 580 +++++++++++++++---
+ gcc/diagnostic.c                              |  10 +-
+ gcc/diagnostic.h                              |  18 +
+ gcc/doc/invoke.texi                           |  43 +-
+ gcc/input.c                                   |  62 +-
+ gcc/input.h                                   |   7 +-
+ gcc/opts.c                                    |   4 +
+ gcc/selftest.c                                |  15 +
+ gcc/selftest.h                                |   2 +
+ .../c-c++-common/diagnostic-format-json-1.c   |   1 +
+ .../c-c++-common/diagnostic-format-json-2.c   |   1 +
+ .../c-c++-common/diagnostic-format-json-3.c   |   1 +
+ .../c-c++-common/diagnostic-format-json-4.c   |   2 +
+ .../c-c++-common/diagnostic-format-json-5.c   |   1 +
+ .../gcc.dg/cpp/warn-normalized-4-bytes.c      |  21 +
+ .../gcc.dg/cpp/warn-normalized-4-unicode.c    |  19 +
+ gcc/testsuite/gcc.dg/encoding-issues-bytes.c  | Bin 0 -> 595 bytes
+ .../gcc.dg/encoding-issues-unicode.c          | Bin 0 -> 613 bytes
+ .../gfortran.dg/diagnostic-format-json-1.F90  |   1 +
+ .../gfortran.dg/diagnostic-format-json-2.F90  |   1 +
+ .../gfortran.dg/diagnostic-format-json-3.F90  |   1 +
+ libcpp/charset.c                              |  63 +-
+ libcpp/errors.c                               |  82 ++-
+ libcpp/include/cpplib.h                       |  76 ++-
+ libcpp/include/line-map.h                     |  13 +
+ libcpp/internal.h                             |  23 +
+ libcpp/lex.c                                  |  38 +-
+ libcpp/line-map.c                             |   3 +-
+ 31 files changed, 942 insertions(+), 168 deletions(-)
+ create mode 100644 gcc/testsuite/gcc.dg/cpp/warn-normalized-4-bytes.c
+ create mode 100644 gcc/testsuite/gcc.dg/cpp/warn-normalized-4-unicode.c
+ create mode 100644 gcc/testsuite/gcc.dg/encoding-issues-bytes.c
+ create mode 100644 gcc/testsuite/gcc.dg/encoding-issues-unicode.c
+
+diff --git a/gcc/c-family/c-lex.c b/gcc/c-family/c-lex.c
+--- a/gcc/c-family/c-lex.c      2020-07-22 23:35:17.296384022 -0700
++++ b/gcc/c-family/c-lex.c      2021-12-25 01:30:50.669689023 -0800
+@@ -587,7 +587,11 @@ c_lex_with_flags (tree *value, location_
+        else if (ISGRAPH (c))
+          error_at (*loc, "stray %qc in program", (int) c);
+        else
+-         error_at (*loc, "stray %<\\%o%> in program", (int) c);
++         {
++           rich_location rich_loc (line_table, *loc);
++           rich_loc.set_escape_on_output (true);
++           error_at (&rich_loc, "stray %<\\%o%> in program", (int) c);
++         }
+       }
+       goto retry;
+ 
+diff --git a/gcc/common.opt b/gcc/common.opt
+--- a/gcc/common.opt    2021-12-25 01:29:12.915317374 -0800
++++ b/gcc/common.opt    2021-12-25 01:30:50.669689023 -0800
+@@ -1337,6 +1337,10 @@ fdiagnostics-format=
+ Common Joined RejectNegative Enum(diagnostics_output_format)
+ -fdiagnostics-format=[text|json]       Select output format.
+ 
++fdiagnostics-escape-format=
++Common Joined RejectNegative Enum(diagnostics_escape_format)
++-fdiagnostics-escape-format=[unicode|bytes]    Select how to escape non-printable-ASCII bytes in the source for diagnostics that suggest it.
++
+ ; Required for these enum values.
+ SourceInclude
+ diagnostic.h
+@@ -1351,6 +1355,15 @@ EnumValue
+ Enum(diagnostics_column_unit) String(byte) Value(DIAGNOSTICS_COLUMN_UNIT_BYTE)
+ 
+ Enum
++Name(diagnostics_escape_format) Type(int)
++
++EnumValue
++Enum(diagnostics_escape_format) String(unicode) Value(DIAGNOSTICS_ESCAPE_FORMAT_UNICODE)
++
++EnumValue
++Enum(diagnostics_escape_format) String(bytes) Value(DIAGNOSTICS_ESCAPE_FORMAT_BYTES)
++
++Enum
+ Name(diagnostics_output_format) Type(int)
+ 
+ EnumValue
+diff --git a/gcc/diagnostic.c b/gcc/diagnostic.c
+--- a/gcc/diagnostic.c  2021-12-25 01:29:12.915317374 -0800
++++ b/gcc/diagnostic.c  2021-12-25 01:30:50.669689023 -0800
+@@ -223,6 +223,7 @@ diagnostic_initialize (diagnostic_contex
+   context->column_unit = DIAGNOSTICS_COLUMN_UNIT_DISPLAY;
+   context->column_origin = 1;
+   context->tabstop = 8;
++  context->escape_format = DIAGNOSTICS_ESCAPE_FORMAT_UNICODE;
+   context->edit_context_ptr = NULL;
+   context->diagnostic_group_nesting_depth = 0;
+   context->diagnostic_group_emission_count = 0;
+@@ -2152,8 +2153,8 @@ test_diagnostic_get_location_text ()
+     const char *const content = "smile \xf0\x9f\x98\x82\n";
+     const int line_bytes = strlen (content) - 1;
+     const int def_tabstop = 8;
+-    const int display_width = cpp_display_width (content, line_bytes,
+-                                                def_tabstop);
++    const cpp_char_column_policy policy (def_tabstop, cpp_wcwidth);
++    const int display_width = cpp_display_width (content, line_bytes, policy);
+     ASSERT_EQ (line_bytes - 2, display_width);
+     temp_source_file tmp (SELFTEST_LOCATION, ".c", content);
+     const char *const fname = tmp.get_filename ();
+diff --git a/gcc/diagnostic-format-json.cc b/gcc/diagnostic-format-json.cc
+--- a/gcc/diagnostic-format-json.cc     2021-12-25 01:29:12.915317374 -0800
++++ b/gcc/diagnostic-format-json.cc     2021-12-25 01:30:50.669689023 -0800
+@@ -264,6 +264,9 @@ json_end_diagnostic (diagnostic_context
+       json::value *path_value = context->make_json_for_path (context, path);
+       diag_obj->set ("path", path_value);
+     }
++
++  diag_obj->set ("escape-source",
++                new json::literal (richloc->escape_on_output_p ()));
+ }
+ 
+ /* No-op implementation of "begin_group_cb" for JSON output.  */
+diff --git a/gcc/diagnostic.h b/gcc/diagnostic.h
+--- a/gcc/diagnostic.h  2021-12-25 01:29:12.919317307 -0800
++++ b/gcc/diagnostic.h  2021-12-25 01:30:50.669689023 -0800
+@@ -38,6 +38,20 @@ enum diagnostics_column_unit
+   DIAGNOSTICS_COLUMN_UNIT_BYTE
+ };
+ 
++/* An enum for controlling how to print non-ASCII characters/bytes when
++   a diagnostic suggests escaping the source code on output.  */
++
++enum diagnostics_escape_format
++{
++  /* Escape non-ASCII Unicode characters in the form <U+XXXX> and
++     non-UTF-8 bytes in the form <XX>.  */
++  DIAGNOSTICS_ESCAPE_FORMAT_UNICODE,
++
++  /* Escape non-ASCII bytes in the form <XX> (thus showing the underlying
++     encoding of non-ASCII Unicode characters).  */
++  DIAGNOSTICS_ESCAPE_FORMAT_BYTES
++};
++
+ /* Enum for overriding the standard output format.  */
+ 
+ enum diagnostics_output_format
+@@ -303,6 +317,10 @@ struct diagnostic_context
+   /* The size of the tabstop for tab expansion.  */
+   int tabstop;
+ 
++  /* How should non-ASCII/non-printable bytes be escaped when
++     a diagnostic suggests escaping the source code on output.  */
++  enum diagnostics_escape_format escape_format;
++
+   /* If non-NULL, an edit_context to which fix-it hints should be
+      applied, for generating patches.  */
+   edit_context *edit_context_ptr;
+diff --git a/gcc/diagnostic-show-locus.c b/gcc/diagnostic-show-locus.c
+--- a/gcc/diagnostic-show-locus.c       2021-12-25 01:29:12.919317307 -0800
++++ b/gcc/diagnostic-show-locus.c       2021-12-25 01:30:50.673688956 -0800
+@@ -175,10 +175,26 @@ enum column_unit {
+ class exploc_with_display_col : public expanded_location
+ {
+  public:
+-  exploc_with_display_col (const expanded_location &exploc, int tabstop)
+-    : expanded_location (exploc),
+-      m_display_col (location_compute_display_column (exploc, tabstop))
+-  {}
++  exploc_with_display_col (const expanded_location &exploc,
++                          const cpp_char_column_policy &policy,
++                          enum location_aspect aspect)
++  : expanded_location (exploc),
++    m_display_col (location_compute_display_column (exploc, policy))
++  {
++    if (exploc.column > 0)
++      {
++       /* m_display_col is now the final column of the byte.
++          If escaping has happened, we may want the first column instead.  */
++       if (aspect != LOCATION_ASPECT_FINISH)
++         {
++           expanded_location prev_exploc (exploc);
++           prev_exploc.column--;
++           int prev_display_col
++             = (location_compute_display_column (prev_exploc, policy));
++           m_display_col = prev_display_col + 1;
++         }
++      }
++  }
+ 
+   int m_display_col;
+ };
+@@ -313,6 +329,31 @@ test_line_span ()
+ 
+ #endif /* #if CHECKING_P */
+ 
++/* A bundle of information containing how to print unicode
++   characters and bytes when quoting source code.
++
++   Provides a unified place to support escaping some subset
++   of characters to some format.
++
++   Extends char_column_policy; printing is split out to avoid
++   libcpp having to know about pretty_printer.  */
++
++struct char_display_policy : public cpp_char_column_policy
++{
++ public:
++  char_display_policy (int tabstop,
++                      int (*width_cb) (cppchar_t c),
++                      void (*print_cb) (pretty_printer *pp,
++                                        const cpp_decoded_char &cp))
++  : cpp_char_column_policy (tabstop, width_cb),
++    m_print_cb (print_cb)
++  {
++  }
++
++  void (*m_print_cb) (pretty_printer *pp,
++                     const cpp_decoded_char &cp);
++};
++
+ /* A class to control the overall layout when printing a diagnostic.
+ 
+    The layout is determined within the constructor.
+@@ -345,6 +386,8 @@ class layout
+ 
+   void print_line (linenum_type row);
+ 
++  void on_bad_codepoint (const char *ptr, cppchar_t ch, size_t ch_sz);
++
+  private:
+   bool will_show_line_p (linenum_type row) const;
+   void print_leading_fixits (linenum_type row);
+@@ -386,6 +429,7 @@ class layout
+  private:
+   diagnostic_context *m_context;
+   pretty_printer *m_pp;
++  char_display_policy m_policy;
+   location_t m_primary_loc;
+   exploc_with_display_col m_exploc;
+   colorizer m_colorizer;
+@@ -398,6 +442,7 @@ class layout
+   auto_vec <line_span> m_line_spans;
+   int m_linenum_width;
+   int m_x_offset_display;
++  bool m_escape_on_output;
+ };
+ 
+ /* Implementation of "class colorizer".  */
+@@ -646,6 +691,11 @@ layout_range::intersects_line_p (linenum
+ /* Default for when we don't care what the tab expansion is set to.  */
+ static const int def_tabstop = 8;
+ 
++static cpp_char_column_policy def_policy ()
++{
++  return cpp_char_column_policy (8, cpp_wcwidth);
++}
++
+ /* Create some expanded locations for testing layout_range.  The filename
+    member of the explocs is set to the empty string.  This member will only be
+    inspected by the calls to location_compute_display_column() made from the
+@@ -662,10 +712,13 @@ make_range (int start_line, int start_co
+     = {"", start_line, start_col, NULL, false};
+   const expanded_location finish_exploc
+     = {"", end_line, end_col, NULL, false};
+-  return layout_range (exploc_with_display_col (start_exploc, def_tabstop),
+-                      exploc_with_display_col (finish_exploc, def_tabstop),
++  return layout_range (exploc_with_display_col (start_exploc, def_policy (),
++                                               LOCATION_ASPECT_START),
++                      exploc_with_display_col (finish_exploc, def_policy (),
++                                               LOCATION_ASPECT_FINISH),
+                       SHOW_RANGE_WITHOUT_CARET,
+-                      exploc_with_display_col (start_exploc, def_tabstop),
++                      exploc_with_display_col (start_exploc, def_policy (),
++                                               LOCATION_ASPECT_CARET),
+                       0, NULL);
+ }
+ 
+@@ -950,6 +1003,164 @@ fixit_cmp (const void *p_a, const void *
+   return hint_a->get_start_loc () - hint_b->get_start_loc ();
+ }
+ 
++/* Callbacks for use when not escaping the source.  */
++
++/* The default callback for char_column_policy::m_width_cb is cpp_wcwidth.  */
++
++/* Callback for char_display_policy::m_print_cb for printing source chars
++   when not escaping the source.  */
++
++static void
++default_print_decoded_ch (pretty_printer *pp,
++                         const cpp_decoded_char &decoded_ch)
++{
++  for (const char *ptr = decoded_ch.m_start_byte;
++       ptr != decoded_ch.m_next_byte; ptr++)
++    {
++      if (*ptr == '\0' || *ptr == '\r')
++       {
++         pp_space (pp);
++         continue;
++       }
++
++      pp_character (pp, *ptr);
++    }
++}
++
++/* Callbacks for use with DIAGNOSTICS_ESCAPE_FORMAT_BYTES.  */
++
++static const int width_per_escaped_byte = 4;
++
++/* Callback for char_column_policy::m_width_cb for determining the
++   display width when escaping with DIAGNOSTICS_ESCAPE_FORMAT_BYTES.  */
++
++static int
++escape_as_bytes_width (cppchar_t ch)
++{
++  if (ch < 0x80 && ISPRINT (ch))
++    return cpp_wcwidth (ch);
++  else
++    {
++      if (ch <=   0x7F) return 1 * width_per_escaped_byte;
++      if (ch <=  0x7FF) return 2 * width_per_escaped_byte;
++      if (ch <= 0xFFFF) return 3 * width_per_escaped_byte;
++      return 4 * width_per_escaped_byte;
++    }
++}
++
++/* Callback for char_display_policy::m_print_cb for printing source chars
++   when escaping with DIAGNOSTICS_ESCAPE_FORMAT_BYTES.  */
++
++static void
++escape_as_bytes_print (pretty_printer *pp,
++                      const cpp_decoded_char &decoded_ch)
++{
++  if (!decoded_ch.m_valid_ch)
++    {
++      for (const char *iter = decoded_ch.m_start_byte;
++          iter != decoded_ch.m_next_byte; ++iter)
++       {
++         char buf[16];
++         sprintf (buf, "<%02x>", (unsigned char)*iter);
++         pp_string (pp, buf);
++       }
++      return;
++    }
++
++  cppchar_t ch = decoded_ch.m_ch;
++  if (ch < 0x80 && ISPRINT (ch))
++    pp_character (pp, ch);
++  else
++    {
++      for (const char *iter = decoded_ch.m_start_byte;
++          iter < decoded_ch.m_next_byte; ++iter)
++       {
++         char buf[16];
++         sprintf (buf, "<%02x>", (unsigned char)*iter);
++         pp_string (pp, buf);
++       }
++    }
++}
++
++/* Callbacks for use with DIAGNOSTICS_ESCAPE_FORMAT_UNICODE.  */
++
++/* Callback for char_column_policy::m_width_cb for determining the
++   display width when escaping with DIAGNOSTICS_ESCAPE_FORMAT_UNICODE.  */
++
++static int
++escape_as_unicode_width (cppchar_t ch)
++{
++  if (ch < 0x80 && ISPRINT (ch))
++    return cpp_wcwidth (ch);
++  else
++    {
++      // Width of "<U+%04x>"
++      if (ch > 0xfffff)
++       return 10;
++      else if (ch > 0xffff)
++       return 9;
++      else
++       return 8;
++    }
++}
++
++/* Callback for char_display_policy::m_print_cb for printing source chars
++   when escaping with DIAGNOSTICS_ESCAPE_FORMAT_UNICODE.  */
++
++static void
++escape_as_unicode_print (pretty_printer *pp,
++                        const cpp_decoded_char &decoded_ch)
++{
++  if (!decoded_ch.m_valid_ch)
++    {
++      escape_as_bytes_print (pp, decoded_ch);
++      return;
++    }
++
++  cppchar_t ch = decoded_ch.m_ch;
++  if (ch < 0x80 && ISPRINT (ch))
++    pp_character (pp, ch);
++  else
++    {
++      char buf[16];
++      sprintf (buf, "<U+%04X>", ch);
++      pp_string (pp, buf);
++    }
++}
++
++/* Populate a char_display_policy based on DC and RICHLOC.  */
++
++static char_display_policy
++make_policy (const diagnostic_context &dc,
++            const rich_location &richloc)
++{
++  /* The default is to not escape non-ASCII bytes.  */
++  char_display_policy result
++    (dc.tabstop, cpp_wcwidth, default_print_decoded_ch);
++
++  /* If the diagnostic suggests escaping non-ASCII bytes, then
++     use policy from user-supplied options.  */
++  if (richloc.escape_on_output_p ())
++    {
++      result.m_undecoded_byte_width = width_per_escaped_byte;
++      switch (dc.escape_format)
++       {
++       default:
++         gcc_unreachable ();
++       case DIAGNOSTICS_ESCAPE_FORMAT_UNICODE:
++         result.m_width_cb = escape_as_unicode_width;
++         result.m_print_cb = escape_as_unicode_print;
++         break;
++       case DIAGNOSTICS_ESCAPE_FORMAT_BYTES:
++         result.m_width_cb = escape_as_bytes_width;
++         result.m_print_cb = escape_as_bytes_print;
++         break;
++       }
++    }
++
++  return result;
++}
++
+ /* Implementation of class layout.  */
+ 
+ /* Constructor for class layout.
+@@ -966,8 +1177,10 @@ layout::layout (diagnostic_context * con
+                diagnostic_t diagnostic_kind)
+ : m_context (context),
+   m_pp (context->printer),
++  m_policy (make_policy (*context, *richloc)),
+   m_primary_loc (richloc->get_range (0)->m_loc),
+-  m_exploc (richloc->get_expanded_location (0), context->tabstop),
++  m_exploc (richloc->get_expanded_location (0), m_policy,
++           LOCATION_ASPECT_CARET),
+   m_colorizer (context, diagnostic_kind),
+   m_colorize_source_p (context->colorize_source_p),
+   m_show_labels_p (context->show_labels_p),
+@@ -977,7 +1190,8 @@ layout::layout (diagnostic_context * con
+   m_fixit_hints (richloc->get_num_fixit_hints ()),
+   m_line_spans (1 + richloc->get_num_locations ()),
+   m_linenum_width (0),
+-  m_x_offset_display (0)
++  m_x_offset_display (0),
++  m_escape_on_output (richloc->escape_on_output_p ())
+ {
+   for (unsigned int idx = 0; idx < richloc->get_num_locations (); idx++)
+     {
+@@ -1063,10 +1277,13 @@ layout::maybe_add_location_range (const
+ 
+   /* Everything is now known to be in the correct source file,
+      but it may require further sanitization.  */
+-  layout_range ri (exploc_with_display_col (start, m_context->tabstop),
+-                  exploc_with_display_col (finish, m_context->tabstop),
++  layout_range ri (exploc_with_display_col (start, m_policy,
++                                           LOCATION_ASPECT_START),
++                  exploc_with_display_col (finish, m_policy,
++                                           LOCATION_ASPECT_FINISH),
+                   loc_range->m_range_display_kind,
+-                  exploc_with_display_col (caret, m_context->tabstop),
++                  exploc_with_display_col (caret, m_policy,
++                                           LOCATION_ASPECT_CARET),
+                   original_idx, loc_range->m_label);
+ 
+   /* If we have a range that finishes before it starts (perhaps
+@@ -1400,7 +1617,7 @@ layout::calculate_x_offset_display ()
+     = get_line_bytes_without_trailing_whitespace (line.get_buffer (),
+                                                  line.length ());
+   int eol_display_column
+-    = cpp_display_width (line.get_buffer (), line_bytes, m_context->tabstop);
++    = cpp_display_width (line.get_buffer (), line_bytes, m_policy);
+   if (caret_display_column > eol_display_column
+       || !caret_display_column)
+     {
+@@ -1479,7 +1696,7 @@ layout::print_source_line (linenum_type
+   /* This object helps to keep track of which display column we are at, which is
+      necessary for computing the line bounds in display units, for doing
+      tab expansion, and for implementing m_x_offset_display.  */
+-  cpp_display_width_computation dw (line, line_bytes, m_context->tabstop);
++  cpp_display_width_computation dw (line, line_bytes, m_policy);
+ 
+   /* Skip the first m_x_offset_display display columns.  In case the leading
+      portion that will be skipped ends with a character with wcwidth > 1, then
+@@ -1527,7 +1744,8 @@ layout::print_source_line (linenum_type
+         tabs and replacing some control bytes with spaces as necessary.  */
+       const char *c = dw.next_byte ();
+       const int start_disp_col = dw.display_cols_processed () + 1;
+-      const int this_display_width = dw.process_next_codepoint ();
++      cpp_decoded_char cp;
++      const int this_display_width = dw.process_next_codepoint (&cp);
+       if (*c == '\t')
+        {
+          /* The returned display width is the number of spaces into which the
+@@ -1536,15 +1754,6 @@ layout::print_source_line (linenum_type
+            pp_space (m_pp);
+          continue;
+        }
+-      if (*c == '\0' || *c == '\r')
+-       {
+-         /* cpp_wcwidth() promises to return 1 for all control bytes, and we
+-            want to output these as a single space too, so this case is
+-            actually the same as the '\t' case.  */
+-         gcc_assert (this_display_width == 1);
+-         pp_space (m_pp);
+-         continue;
+-       }
+ 
+       /* We have a (possibly multibyte) character to output; update the line
+         bounds if it is not whitespace.  */
+@@ -1556,7 +1765,8 @@ layout::print_source_line (linenum_type
+        }
+ 
+       /* Output the character.  */
+-      while (c != dw.next_byte ()) pp_character (m_pp, *c++);
++      m_policy.m_print_cb (m_pp, cp);
++      c = dw.next_byte ();
+     }
+   print_newline ();
+   return lbounds;
+@@ -1655,14 +1865,14 @@ layout::print_annotation_line (linenum_t
+ class line_label
+ {
+ public:
+-  line_label (diagnostic_context *context, int state_idx, int column,
++  line_label (const cpp_char_column_policy &policy,
++             int state_idx, int column,
+              label_text text)
+   : m_state_idx (state_idx), m_column (column),
+     m_text (text), m_label_line (0), m_has_vbar (true)
+   {
+     const int bytes = strlen (text.m_buffer);
+-    m_display_width
+-      = cpp_display_width (text.m_buffer, bytes, context->tabstop);
++    m_display_width = cpp_display_width (text.m_buffer, bytes, policy);
+   }
+ 
+   /* Sorting is primarily by column, then by state index.  */
+@@ -1722,7 +1932,7 @@ layout::print_any_labels (linenum_type r
+        if (text.m_buffer == NULL)
+          continue;
+ 
+-       labels.safe_push (line_label (m_context, i, disp_col, text));
++       labels.safe_push (line_label (m_policy, i, disp_col, text));
+       }
+   }
+ 
+@@ -2002,7 +2212,7 @@ public:
+ 
+ /* Get the range of bytes or display columns that HINT would affect.  */
+ static column_range
+-get_affected_range (diagnostic_context *context,
++get_affected_range (const cpp_char_column_policy &policy,
+                    const fixit_hint *hint, enum column_unit col_unit)
+ {
+   expanded_location exploc_start = expand_location (hint->get_start_loc ());
+@@ -2013,13 +2223,11 @@ get_affected_range (diagnostic_context *
+   int finish_column;
+   if (col_unit == CU_DISPLAY_COLS)
+     {
+-      start_column
+-       = location_compute_display_column (exploc_start, context->tabstop);
++      start_column = location_compute_display_column (exploc_start, policy);
+       if (hint->insertion_p ())
+        finish_column = start_column - 1;
+       else
+-       finish_column
+-         = location_compute_display_column (exploc_finish, context->tabstop);
++       finish_column = location_compute_display_column (exploc_finish, policy);
+     }
+   else
+     {
+@@ -2032,12 +2240,13 @@ get_affected_range (diagnostic_context *
+ /* Get the range of display columns that would be printed for HINT.  */
+ 
+ static column_range
+-get_printed_columns (diagnostic_context *context, const fixit_hint *hint)
++get_printed_columns (const cpp_char_column_policy &policy,
++                    const fixit_hint *hint)
+ {
+   expanded_location exploc = expand_location (hint->get_start_loc ());
+-  int start_column = location_compute_display_column (exploc, context->tabstop);
++  int start_column = location_compute_display_column (exploc, policy);
+   int hint_width = cpp_display_width (hint->get_string (), hint->get_length (),
+-                                     context->tabstop);
++                                     policy);
+   int final_hint_column = start_column + hint_width - 1;
+   if (hint->insertion_p ())
+     {
+@@ -2047,8 +2256,7 @@ get_printed_columns (diagnostic_context
+     {
+       exploc = expand_location (hint->get_next_loc ());
+       --exploc.column;
+-      int finish_column
+-       = location_compute_display_column (exploc, context->tabstop);
++      int finish_column = location_compute_display_column (exploc, policy);
+       return column_range (start_column,
+                           MAX (finish_column, final_hint_column));
+     }
+@@ -2066,13 +2274,13 @@ public:
+              column_range affected_columns,
+              column_range printed_columns,
+              const char *new_text, size_t new_text_len,
+-             int tabstop)
++             const cpp_char_column_policy &policy)
+   : m_affected_bytes (affected_bytes),
+     m_affected_columns (affected_columns),
+     m_printed_columns (printed_columns),
+     m_text (xstrdup (new_text)),
+     m_byte_length (new_text_len),
+-    m_tabstop (tabstop),
++    m_policy (policy),
+     m_alloc_sz (new_text_len + 1)
+   {
+     compute_display_cols ();
+@@ -2090,7 +2298,7 @@ public:
+ 
+   void compute_display_cols ()
+   {
+-    m_display_cols = cpp_display_width (m_text, m_byte_length, m_tabstop);
++    m_display_cols = cpp_display_width (m_text, m_byte_length, m_policy);
+   }
+ 
+   void overwrite (int dst_offset, const char_span &src_span)
+@@ -2118,7 +2326,7 @@ public:
+   char *m_text;
+   size_t m_byte_length; /* Not including null-terminator.  */
+   int m_display_cols;
+-  int m_tabstop;
++  const cpp_char_column_policy &m_policy;
+   size_t m_alloc_sz;
+ };
+ 
+@@ -2154,15 +2362,16 @@ correction::ensure_terminated ()
+ class line_corrections
+ {
+ public:
+-  line_corrections (diagnostic_context *context, const char *filename,
++  line_corrections (const char_display_policy &policy,
++                   const char *filename,
+                    linenum_type row)
+-    : m_context (context), m_filename (filename), m_row (row)
++  : m_policy (policy), m_filename (filename), m_row (row)
+   {}
+   ~line_corrections ();
+ 
+   void add_hint (const fixit_hint *hint);
+ 
+-  diagnostic_context *m_context;
++  const char_display_policy &m_policy;
+   const char *m_filename;
+   linenum_type m_row;
+   auto_vec <correction *> m_corrections;
+@@ -2208,10 +2417,10 @@ source_line::source_line (const char *fi
+ void
+ line_corrections::add_hint (const fixit_hint *hint)
+ {
+-  column_range affected_bytes = get_affected_range (m_context, hint, CU_BYTES);
+-  column_range affected_columns = get_affected_range (m_context, hint,
++  column_range affected_bytes = get_affected_range (m_policy, hint, CU_BYTES);
++  column_range affected_columns = get_affected_range (m_policy, hint,
+                                                      CU_DISPLAY_COLS);
+-  column_range printed_columns = get_printed_columns (m_context, hint);
++  column_range printed_columns = get_printed_columns (m_policy, hint);
+ 
+   /* Potentially consolidate.  */
+   if (!m_corrections.is_empty ())
+@@ -2280,7 +2489,7 @@ line_corrections::add_hint (const fixit_
+                                           printed_columns,
+                                           hint->get_string (),
+                                           hint->get_length (),
+-                                          m_context->tabstop));
++                                          m_policy));
+ }
+ 
+ /* If there are any fixit hints on source line ROW, print them.
+@@ -2294,7 +2503,7 @@ layout::print_trailing_fixits (linenum_t
+ {
+   /* Build a list of correction instances for the line,
+      potentially consolidating hints (for the sake of readability).  */
+-  line_corrections corrections (m_context, m_exploc.file, row);
++  line_corrections corrections (m_policy, m_exploc.file, row);
+   for (unsigned int i = 0; i < m_fixit_hints.length (); i++)
+     {
+       const fixit_hint *hint = m_fixit_hints[i];
+@@ -2635,6 +2844,59 @@ namespace selftest {
+ 
+ /* Selftests for diagnostic_show_locus.  */
+ 
++/* Verify that cpp_display_width correctly handles escaping.  */
++
++static void
++test_display_widths ()
++{
++  gcc_rich_location richloc (UNKNOWN_LOCATION);
++
++  /* U+03C0 "GREEK SMALL LETTER PI".  */
++  const char *pi = "\xCF\x80";
++  /* U+1F642 "SLIGHTLY SMILING FACE".  */
++  const char *emoji = "\xF0\x9F\x99\x82";
++  /* Stray trailing byte of a UTF-8 character.  */
++  const char *stray = "\xBF";
++  /* U+10FFFF.  */
++  const char *max_codepoint = "\xF4\x8F\xBF\xBF";
++
++  /* No escaping.  */
++  {
++    test_diagnostic_context dc;
++    char_display_policy policy (make_policy (dc, richloc));
++    ASSERT_EQ (cpp_display_width (pi, strlen (pi), policy), 1);
++    ASSERT_EQ (cpp_display_width (emoji, strlen (emoji), policy), 2);
++    ASSERT_EQ (cpp_display_width (stray, strlen (stray), policy), 1);
++    /* Don't check width of U+10FFFF; it's in a private use plane.  */
++  }
++
++  richloc.set_escape_on_output (true);
++
++  {
++    test_diagnostic_context dc;
++    dc.escape_format = DIAGNOSTICS_ESCAPE_FORMAT_UNICODE;
++    char_display_policy policy (make_policy (dc, richloc));
++    ASSERT_EQ (cpp_display_width (pi, strlen (pi), policy), 8);
++    ASSERT_EQ (cpp_display_width (emoji, strlen (emoji), policy), 9);
++    ASSERT_EQ (cpp_display_width (stray, strlen (stray), policy), 4);
++    ASSERT_EQ (cpp_display_width (max_codepoint, strlen (max_codepoint),
++                                 policy),
++              strlen ("<U+10FFFF>"));
++  }
++
++  {
++    test_diagnostic_context dc;
++    dc.escape_format = DIAGNOSTICS_ESCAPE_FORMAT_BYTES;
++    char_display_policy policy (make_policy (dc, richloc));
++    ASSERT_EQ (cpp_display_width (pi, strlen (pi), policy), 8);
++    ASSERT_EQ (cpp_display_width (emoji, strlen (emoji), policy), 16);
++    ASSERT_EQ (cpp_display_width (stray, strlen (stray), policy), 4);
++    ASSERT_EQ (cpp_display_width (max_codepoint, strlen (max_codepoint),
++                                 policy),
++              16);
++  }
++}
++
+ /* For precise tests of the layout, make clear where the source line will
+    start.  test_left_margin sets the total byte count from the left side of the
+    screen to the start of source lines, after the line number and the separator,
+@@ -2704,10 +2966,10 @@ test_layout_x_offset_display_utf8 (const
+   char_span lspan = location_get_source_line (tmp.get_filename (), 1);
+   ASSERT_EQ (line_display_cols,
+             cpp_display_width (lspan.get_buffer (), lspan.length (),
+-                               def_tabstop));
++                               def_policy ()));
+   ASSERT_EQ (line_display_cols,
+             location_compute_display_column (expand_location (line_end),
+-                                             def_tabstop));
++                                             def_policy ()));
+   ASSERT_EQ (0, memcmp (lspan.get_buffer () + (emoji_col - 1),
+                        "\xf0\x9f\x98\x82\xf0\x9f\x98\x82", 8));
+ 
+@@ -2855,12 +3117,13 @@ test_layout_x_offset_display_tab (const
+   ASSERT_EQ ('\t', *(lspan.get_buffer () + (tab_col - 1)));
+   for (int tabstop = 1; tabstop != num_tabstops; ++tabstop)
+     {
++      cpp_char_column_policy policy (tabstop, cpp_wcwidth);
+       ASSERT_EQ (line_bytes + extra_width[tabstop],
+                 cpp_display_width (lspan.get_buffer (), lspan.length (),
+-                                   tabstop));
++                                   policy));
+       ASSERT_EQ (line_bytes + extra_width[tabstop],
+                 location_compute_display_column (expand_location (line_end),
+-                                                 tabstop));
++                                                 policy));
+     }
+ 
+   /* Check that the tab is expanded to the expected number of spaces.  */
+@@ -3992,6 +4255,43 @@ test_one_liner_labels_utf8 ()
+                           " bb\xf0\x9f\x98\x82\xf0\x9f\x98\x82\n",
+                  pp_formatted_text (dc.printer));
+   }
++
++  /* Example of escaping the source lines.  */
++  {
++    text_range_label label0 ("label 0\xf0\x9f\x98\x82");
++    text_range_label label1 ("label 1\xcf\x80");
++    text_range_label label2 ("label 2\xcf\x80");
++    gcc_rich_location richloc (foo, &label0);
++    richloc.add_range (bar, SHOW_RANGE_WITHOUT_CARET, &label1);
++    richloc.add_range (field, SHOW_RANGE_WITHOUT_CARET, &label2);
++    richloc.set_escape_on_output (true);
++
++    {
++      test_diagnostic_context dc;
++      dc.escape_format = DIAGNOSTICS_ESCAPE_FORMAT_UNICODE;
++      diagnostic_show_locus (&dc, &richloc, DK_ERROR);
++      ASSERT_STREQ (" <U+1F602>_foo = <U+03C0>_bar.<U+1F602>_field<U+03C0>;\n"
++                   " ^~~~~~~~~~~~~   ~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~\n"
++                   " |               |            |\n"
++                   " |               |            label 2\xcf\x80\n"
++                   " |               label 1\xcf\x80\n"
++                   " label 0\xf0\x9f\x98\x82\n",
++                   pp_formatted_text (dc.printer));
++    }
++    {
++      test_diagnostic_context dc;
++      dc.escape_format = DIAGNOSTICS_ESCAPE_FORMAT_BYTES;
++      diagnostic_show_locus (&dc, &richloc, DK_ERROR);
++      ASSERT_STREQ
++       (" <f0><9f><98><82>_foo = <cf><80>_bar.<f0><9f><98><82>_field<cf><80>;\n"
++        " ^~~~~~~~~~~~~~~~~~~~   ~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n"
++        " |                      |            |\n"
++        " |                      |            label 2\xcf\x80\n"
++        " |                      label 1\xcf\x80\n"
++        " label 0\xf0\x9f\x98\x82\n",
++        pp_formatted_text (dc.printer));
++    }
++  }
+ }
+ 
+ /* Make sure that colorization codes don't interrupt a multibyte
+@@ -4046,9 +4346,9 @@ test_diagnostic_show_locus_one_liner_utf
+ 
+   char_span lspan = location_get_source_line (tmp.get_filename (), 1);
+   ASSERT_EQ (25, cpp_display_width (lspan.get_buffer (), lspan.length (),
+-                                   def_tabstop));
++                                   def_policy ()));
+   ASSERT_EQ (25, location_compute_display_column (expand_location (line_end),
+-                                                 def_tabstop));
++                                                 def_policy ()));
+ 
+   test_one_liner_simple_caret_utf8 ();
+   test_one_liner_caret_and_range_utf8 ();
+@@ -4434,30 +4734,31 @@ test_overlapped_fixit_printing (const li
+                  pp_formatted_text (dc.printer));
+ 
+     /* Unit-test the line_corrections machinery.  */
++    char_display_policy policy (make_policy (dc, richloc));
+     ASSERT_EQ (3, richloc.get_num_fixit_hints ());
+     const fixit_hint *hint_0 = richloc.get_fixit_hint (0);
+     ASSERT_EQ (column_range (12, 12),
+-              get_affected_range (&dc, hint_0, CU_BYTES));
++              get_affected_range (policy, hint_0, CU_BYTES));
+     ASSERT_EQ (column_range (12, 12),
+-              get_affected_range (&dc, hint_0, CU_DISPLAY_COLS));
+-    ASSERT_EQ (column_range (12, 22), get_printed_columns (&dc, hint_0));
++              get_affected_range (policy, hint_0, CU_DISPLAY_COLS));
++    ASSERT_EQ (column_range (12, 22), get_printed_columns (policy, hint_0));
+     const fixit_hint *hint_1 = richloc.get_fixit_hint (1);
+     ASSERT_EQ (column_range (18, 18),
+-              get_affected_range (&dc, hint_1, CU_BYTES));
++              get_affected_range (policy, hint_1, CU_BYTES));
+     ASSERT_EQ (column_range (18, 18),
+-              get_affected_range (&dc, hint_1, CU_DISPLAY_COLS));
+-    ASSERT_EQ (column_range (18, 20), get_printed_columns (&dc, hint_1));
++              get_affected_range (policy, hint_1, CU_DISPLAY_COLS));
++    ASSERT_EQ (column_range (18, 20), get_printed_columns (policy, hint_1));
+     const fixit_hint *hint_2 = richloc.get_fixit_hint (2);
+     ASSERT_EQ (column_range (29, 28),
+-              get_affected_range (&dc, hint_2, CU_BYTES));
++              get_affected_range (policy, hint_2, CU_BYTES));
+     ASSERT_EQ (column_range (29, 28),
+-              get_affected_range (&dc, hint_2, CU_DISPLAY_COLS));
+-    ASSERT_EQ (column_range (29, 29), get_printed_columns (&dc, hint_2));
++              get_affected_range (policy, hint_2, CU_DISPLAY_COLS));
++    ASSERT_EQ (column_range (29, 29), get_printed_columns (policy, hint_2));
+ 
+     /* Add each hint in turn to a line_corrections instance,
+        and verify that they are consolidated into one correction instance
+        as expected.  */
+-    line_corrections lc (&dc, tmp.get_filename (), 1);
++    line_corrections lc (policy, tmp.get_filename (), 1);
+ 
+     /* The first replace hint by itself.  */
+     lc.add_hint (hint_0);
+@@ -4649,30 +4950,31 @@ test_overlapped_fixit_printing_utf8 (con
+                  pp_formatted_text (dc.printer));
+ 
+     /* Unit-test the line_corrections machinery.  */
++    char_display_policy policy (make_policy (dc, richloc));
+     ASSERT_EQ (3, richloc.get_num_fixit_hints ());
+     const fixit_hint *hint_0 = richloc.get_fixit_hint (0);
+     ASSERT_EQ (column_range (14, 14),
+-              get_affected_range (&dc, hint_0, CU_BYTES));
++              get_affected_range (policy, hint_0, CU_BYTES));
+     ASSERT_EQ (column_range (12, 12),
+-              get_affected_range (&dc, hint_0, CU_DISPLAY_COLS));
+-    ASSERT_EQ (column_range (12, 22), get_printed_columns (&dc, hint_0));
++              get_affected_range (policy, hint_0, CU_DISPLAY_COLS));
++    ASSERT_EQ (column_range (12, 22), get_printed_columns (policy, hint_0));
+     const fixit_hint *hint_1 = richloc.get_fixit_hint (1);
+     ASSERT_EQ (column_range (22, 22),
+-              get_affected_range (&dc, hint_1, CU_BYTES));
++              get_affected_range (policy, hint_1, CU_BYTES));
+     ASSERT_EQ (column_range (18, 18),
+-              get_affected_range (&dc, hint_1, CU_DISPLAY_COLS));
+-    ASSERT_EQ (column_range (18, 20), get_printed_columns (&dc, hint_1));
++              get_affected_range (policy, hint_1, CU_DISPLAY_COLS));
++    ASSERT_EQ (column_range (18, 20), get_printed_columns (policy, hint_1));
+     const fixit_hint *hint_2 = richloc.get_fixit_hint (2);
+     ASSERT_EQ (column_range (35, 34),
+-              get_affected_range (&dc, hint_2, CU_BYTES));
++              get_affected_range (policy, hint_2, CU_BYTES));
+     ASSERT_EQ (column_range (30, 29),
+-              get_affected_range (&dc, hint_2, CU_DISPLAY_COLS));
+-    ASSERT_EQ (column_range (30, 30), get_printed_columns (&dc, hint_2));
++              get_affected_range (policy, hint_2, CU_DISPLAY_COLS));
++    ASSERT_EQ (column_range (30, 30), get_printed_columns (policy, hint_2));
+ 
+     /* Add each hint in turn to a line_corrections instance,
+        and verify that they are consolidated into one correction instance
+        as expected.  */
+-    line_corrections lc (&dc, tmp.get_filename (), 1);
++    line_corrections lc (policy, tmp.get_filename (), 1);
+ 
+     /* The first replace hint by itself.  */
+     lc.add_hint (hint_0);
+@@ -4866,15 +5168,16 @@ test_overlapped_fixit_printing_2 (const
+     richloc.add_fixit_insert_before (col_21, "}");
+ 
+     /* These fixits should be accepted; they can't be consolidated.  */
++    char_display_policy policy (make_policy (dc, richloc));
+     ASSERT_EQ (2, richloc.get_num_fixit_hints ());
+     const fixit_hint *hint_0 = richloc.get_fixit_hint (0);
+     ASSERT_EQ (column_range (23, 22),
+-              get_affected_range (&dc, hint_0, CU_BYTES));
+-    ASSERT_EQ (column_range (23, 23), get_printed_columns (&dc, hint_0));
++              get_affected_range (policy, hint_0, CU_BYTES));
++    ASSERT_EQ (column_range (23, 23), get_printed_columns (policy, hint_0));
+     const fixit_hint *hint_1 = richloc.get_fixit_hint (1);
+     ASSERT_EQ (column_range (21, 20),
+-              get_affected_range (&dc, hint_1, CU_BYTES));
+-    ASSERT_EQ (column_range (21, 21), get_printed_columns (&dc, hint_1));
++              get_affected_range (policy, hint_1, CU_BYTES));
++    ASSERT_EQ (column_range (21, 21), get_printed_columns (policy, hint_1));
+ 
+     /* Verify that they're printed correctly.  */
+     diagnostic_show_locus (&dc, &richloc, DK_ERROR);
+@@ -5141,10 +5444,11 @@ test_tab_expansion (const line_table_cas
+      ....................123 45678901234 56789012345  columns  */
+ 
+   const int tabstop = 8;
++  cpp_char_column_policy policy (tabstop, cpp_wcwidth);
+   const int first_non_ws_byte_col = 7;
+   const int right_quote_byte_col = 15;
+   const int last_byte_col = 25;
+-  ASSERT_EQ (35, cpp_display_width (content, last_byte_col, tabstop));
++  ASSERT_EQ (35, cpp_display_width (content, last_byte_col, policy));
+ 
+   temp_source_file tmp (SELFTEST_LOCATION, ".c", content);
+   line_table_test ltt (case_);
+@@ -5187,6 +5491,114 @@ test_tab_expansion (const line_table_cas
+   }
+ }
+ 
++/* Verify that the escaping machinery can cope with a variety of different
++   invalid bytes.  */
++
++static void
++test_escaping_bytes_1 (const line_table_case &case_)
++{
++  const char content[] = "before\0\1\2\3\r\x80\xff""after\n";
++  const size_t sz = sizeof (content);
++  temp_source_file tmp (SELFTEST_LOCATION, ".c", content, sz);
++  line_table_test ltt (case_);
++  const line_map_ordinary *ord_map = linemap_check_ordinary
++    (linemap_add (line_table, LC_ENTER, false, tmp.get_filename (), 0));
++  linemap_line_start (line_table, 1, 100);
++
++  location_t finish
++    = linemap_position_for_line_and_column (line_table, ord_map, 1,
++                                           strlen (content));
++
++  if (finish > LINE_MAP_MAX_LOCATION_WITH_COLS)
++    return;
++
++  /* Locations of the NUL and \r bytes.  */
++  location_t nul_loc
++    = linemap_position_for_line_and_column (line_table, ord_map, 1, 7);
++  location_t r_loc
++    = linemap_position_for_line_and_column (line_table, ord_map, 1, 11);
++  gcc_rich_location richloc (nul_loc);
++  richloc.add_range (r_loc);
++
++  {
++    test_diagnostic_context dc;
++    diagnostic_show_locus (&dc, &richloc, DK_ERROR);
++    ASSERT_STREQ (" before \1\2\3 \x80\xff""after\n"
++                 "       ^   ~\n",
++                 pp_formatted_text (dc.printer));
++  }
++  richloc.set_escape_on_output (true);
++  {
++    test_diagnostic_context dc;
++    dc.escape_format = DIAGNOSTICS_ESCAPE_FORMAT_UNICODE;
++    diagnostic_show_locus (&dc, &richloc, DK_ERROR);
++    ASSERT_STREQ
++      (" before<U+0000><U+0001><U+0002><U+0003><U+000D><80><ff>after\n"
++       "       ^~~~~~~~                        ~~~~~~~~\n",
++       pp_formatted_text (dc.printer));
++  }
++  {
++    test_diagnostic_context dc;
++    dc.escape_format = DIAGNOSTICS_ESCAPE_FORMAT_BYTES;
++    diagnostic_show_locus (&dc, &richloc, DK_ERROR);
++    ASSERT_STREQ (" before<00><01><02><03><0d><80><ff>after\n"
++                 "       ^~~~            ~~~~\n",
++                 pp_formatted_text (dc.printer));
++  }
++}
++
++/* As above, but verify that we handle the initial byte of a line
++   correctly.  */
++
++static void
++test_escaping_bytes_2 (const line_table_case &case_)
++{
++  const char content[]  = "\0after\n";
++  const size_t sz = sizeof (content);
++  temp_source_file tmp (SELFTEST_LOCATION, ".c", content, sz);
++  line_table_test ltt (case_);
++  const line_map_ordinary *ord_map = linemap_check_ordinary
++    (linemap_add (line_table, LC_ENTER, false, tmp.get_filename (), 0));
++  linemap_line_start (line_table, 1, 100);
++
++  location_t finish
++    = linemap_position_for_line_and_column (line_table, ord_map, 1,
++                                           strlen (content));
++
++  if (finish > LINE_MAP_MAX_LOCATION_WITH_COLS)
++    return;
++
++  /* Location of the NUL byte.  */
++  location_t nul_loc
++    = linemap_position_for_line_and_column (line_table, ord_map, 1, 1);
++  gcc_rich_location richloc (nul_loc);
++
++  {
++    test_diagnostic_context dc;
++    diagnostic_show_locus (&dc, &richloc, DK_ERROR);
++    ASSERT_STREQ ("  after\n"
++                 " ^\n",
++                 pp_formatted_text (dc.printer));
++  }
++  richloc.set_escape_on_output (true);
++  {
++    test_diagnostic_context dc;
++    dc.escape_format = DIAGNOSTICS_ESCAPE_FORMAT_UNICODE;
++    diagnostic_show_locus (&dc, &richloc, DK_ERROR);
++    ASSERT_STREQ (" <U+0000>after\n"
++                 " ^~~~~~~~\n",
++                 pp_formatted_text (dc.printer));
++  }
++  {
++    test_diagnostic_context dc;
++    dc.escape_format = DIAGNOSTICS_ESCAPE_FORMAT_BYTES;
++    diagnostic_show_locus (&dc, &richloc, DK_ERROR);
++    ASSERT_STREQ (" <00>after\n"
++                 " ^~~~\n",
++                 pp_formatted_text (dc.printer));
++  }
++}
++
+ /* Verify that line numbers are correctly printed for the case of
+    a multiline range in which the width of the line numbers changes
+    (e.g. from "9" to "10").  */
+@@ -5243,6 +5655,8 @@ diagnostic_show_locus_c_tests ()
+   test_layout_range_for_single_line ();
+   test_layout_range_for_multiple_lines ();
+ 
++  test_display_widths ();
++
+   for_each_line_table_case (test_layout_x_offset_display_utf8);
+   for_each_line_table_case (test_layout_x_offset_display_tab);
+ 
+@@ -5263,6 +5677,8 @@ diagnostic_show_locus_c_tests ()
+   for_each_line_table_case (test_fixit_replace_containing_newline);
+   for_each_line_table_case (test_fixit_deletion_affecting_newline);
+   for_each_line_table_case (test_tab_expansion);
++  for_each_line_table_case (test_escaping_bytes_1);
++  for_each_line_table_case (test_escaping_bytes_2);
+ 
+   test_line_numbers_multiline_range ();
+ }
+diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
+--- a/gcc/doc/invoke.texi       2021-12-25 01:29:12.927317174 -0800
++++ b/gcc/doc/invoke.texi       2021-12-25 01:30:50.681688823 -0800
+@@ -295,7 +295,8 @@ Objective-C and Objective-C++ Dialects}.
+ -fdiagnostics-show-path-depths @gol
+ -fno-show-column @gol
+ -fdiagnostics-column-unit=@r{[}display@r{|}byte@r{]} @gol
+--fdiagnostics-column-origin=@var{origin}}
++-fdiagnostics-column-origin=@var{origin} @gol
++-fdiagnostics-escape-format=@r{[}unicode@r{|}bytes@r{]}}
+ 
+ @item Warning Options
+ @xref{Warning Options,,Options to Request or Suppress Warnings}.
+@@ -4451,6 +4452,38 @@ first column.  The default value of 1 co
+ behavior and to the GNU style guide.  Some utilities may perform better with an
+ origin of 0; any non-negative value may be specified.
+ 
++@item -fdiagnostics-escape-format=@var{FORMAT}
++@opindex fdiagnostics-escape-format
++When GCC prints pertinent source lines for a diagnostic it normally attempts
++to print the source bytes directly.  However, some diagnostics relate to encoding
++issues in the source file, such as malformed UTF-8, or issues with Unicode
++normalization.  These diagnostics are flagged so that GCC will escape bytes
++that are not printable ASCII when printing their pertinent source lines.
++
++This option controls how such bytes should be escaped.
++
++The default @var{FORMAT}, @samp{unicode} displays Unicode characters that
++are not printable ASCII in the form @samp{<U+XXXX>}, and bytes that do not
++correspond to a Unicode character validly-encoded in UTF-8-encoded will be
++displayed as hexadecimal in the form @samp{<XX>}.
++
++For example, a source line containing the string @samp{before} followed by the
++Unicode character U+03C0 (``GREEK SMALL LETTER PI'', with UTF-8 encoding
++0xCF 0x80) followed by the byte 0xBF (a stray UTF-8 trailing byte), followed by
++the string @samp{after} will be printed for such a diagnostic as:
++
++@smallexample
++ before<U+03C0><BF>after
++@end smallexample
++
++Setting @var{FORMAT} to @samp{bytes} will display all non-printable-ASCII bytes
++in the form @samp{<XX>}, thus showing the underlying encoding of non-ASCII
++Unicode characters.  For the example above, the following will be printed:
++
++@smallexample
++ before<CF><80><BF>after
++@end smallexample
++
+ @item -fdiagnostics-format=@var{FORMAT}
+ @opindex fdiagnostics-format
+ Select a different format for printing diagnostics.
+@@ -4518,9 +4551,11 @@ might be printed in JSON form (after for
+                         @}
+                     @}
+                 ],
++                "escape-source": false,
+                 "message": "...this statement, but the latter is @dots{}"
+             @}
+         ]
++       "escape-source": false,
+        "column-origin": 1,
+     @},
+     @dots{}
+@@ -4607,6 +4642,7 @@ of the expression, which have labels.  I
+                 "label": "T @{aka struct t@}"
+             @}
+         ],
++        "escape-source": false,
+         "message": "invalid operands to binary + @dots{}"
+     @}
+ @end smallexample
+@@ -4660,6 +4696,7 @@ might be printed in JSON form as:
+                 @}
+             @}
+         ],
++        "escape-source": false,
+         "message": "\u2018struct s\u2019 has no member named @dots{}"
+     @}
+ @end smallexample
+@@ -4717,6 +4754,10 @@ For example, the intraprocedural example
+     ]
+ @end smallexample
+ 
++Diagnostics have a boolean attribute @code{escape-source}, hinting whether
++non-ASCII bytes should be escaped when printing the pertinent lines of
++source code (@code{true} for diagnostics involving source encoding issues).
++
+ @end table
+ 
+ @node Warning Options
+diff --git a/gcc/input.c b/gcc/input.c
+--- a/gcc/input.c       2021-12-25 01:29:12.927317174 -0800
++++ b/gcc/input.c       2021-12-25 01:30:50.681688823 -0800
+@@ -913,7 +913,8 @@ make_location (location_t caret, source_
+    source line in order to calculate the display width.  If that cannot be done
+    for any reason, then returns the byte column as a fallback.  */
+ int
+-location_compute_display_column (expanded_location exploc, int tabstop)
++location_compute_display_column (expanded_location exploc,
++                                const cpp_char_column_policy &policy)
+ {
+   if (!(exploc.file && *exploc.file && exploc.line && exploc.column))
+     return exploc.column;
+@@ -921,7 +922,7 @@ location_compute_display_column (expande
+   /* If line is NULL, this function returns exploc.column which is the
+      desired fallback.  */
+   return cpp_byte_column_to_display_column (line.get_buffer (), line.length (),
+-                                           exploc.column, tabstop);
++                                           exploc.column, policy);
+ }
+ 
+ /* Dump statistics to stderr about the memory usage of the line_table
+@@ -3609,43 +3610,50 @@ test_line_offset_overflow ()
+ void test_cpp_utf8 ()
+ {
+   const int def_tabstop = 8;
++  cpp_char_column_policy policy (def_tabstop, cpp_wcwidth);
++
+   /* Verify that wcwidth of invalid UTF-8 or control bytes is 1.  */
+   {
+-    int w_bad = cpp_display_width ("\xf0!\x9f!\x98!\x82!", 8, def_tabstop);
++    int w_bad = cpp_display_width ("\xf0!\x9f!\x98!\x82!", 8, policy);
+     ASSERT_EQ (8, w_bad);
+-    int w_ctrl = cpp_display_width ("\r\n\v\0\1", 5, def_tabstop);
++    int w_ctrl = cpp_display_width ("\r\n\v\0\1", 5, policy);
+     ASSERT_EQ (5, w_ctrl);
+   }
+ 
+   /* Verify that wcwidth of valid UTF-8 is as expected.  */
+   {
+-    const int w_pi = cpp_display_width ("\xcf\x80", 2, def_tabstop);
++    const int w_pi = cpp_display_width ("\xcf\x80", 2, policy);
+     ASSERT_EQ (1, w_pi);
+-    const int w_emoji = cpp_display_width ("\xf0\x9f\x98\x82", 4, def_tabstop);
++    const int w_emoji = cpp_display_width ("\xf0\x9f\x98\x82", 4, policy);
+     ASSERT_EQ (2, w_emoji);
+     const int w_umlaut_precomposed = cpp_display_width ("\xc3\xbf", 2,
+-                                                       def_tabstop);
++                                                       policy);
+     ASSERT_EQ (1, w_umlaut_precomposed);
+     const int w_umlaut_combining = cpp_display_width ("y\xcc\x88", 3,
+-                                                     def_tabstop);
++                                                     policy);
+     ASSERT_EQ (1, w_umlaut_combining);
+-    const int w_han = cpp_display_width ("\xe4\xb8\xba", 3, def_tabstop);
++    const int w_han = cpp_display_width ("\xe4\xb8\xba", 3, policy);
+     ASSERT_EQ (2, w_han);
+-    const int w_ascii = cpp_display_width ("GCC", 3, def_tabstop);
++    const int w_ascii = cpp_display_width ("GCC", 3, policy);
+     ASSERT_EQ (3, w_ascii);
+     const int w_mixed = cpp_display_width ("\xcf\x80 = 3.14 \xf0\x9f\x98\x82"
+                                           "\x9f! \xe4\xb8\xba y\xcc\x88",
+-                                          24, def_tabstop);
++                                          24, policy);
+     ASSERT_EQ (18, w_mixed);
+   }
+ 
+   /* Verify that display width properly expands tabs.  */
+   {
+     const char *tstr = "\tabc\td";
+-    ASSERT_EQ (6, cpp_display_width (tstr, 6, 1));
+-    ASSERT_EQ (10, cpp_display_width (tstr, 6, 3));
+-    ASSERT_EQ (17, cpp_display_width (tstr, 6, 8));
+-    ASSERT_EQ (1, cpp_display_column_to_byte_column (tstr, 6, 7, 8));
++    ASSERT_EQ (6, cpp_display_width (tstr, 6,
++                                    cpp_char_column_policy (1, cpp_wcwidth)));
++    ASSERT_EQ (10, cpp_display_width (tstr, 6,
++                                     cpp_char_column_policy (3, cpp_wcwidth)));
++    ASSERT_EQ (17, cpp_display_width (tstr, 6,
++                                     cpp_char_column_policy (8, cpp_wcwidth)));
++    ASSERT_EQ (1,
++              cpp_display_column_to_byte_column
++                (tstr, 6, 7, cpp_char_column_policy (8, cpp_wcwidth)));
+   }
+ 
+   /* Verify that cpp_byte_column_to_display_column can go past the end,
+@@ -3658,13 +3666,13 @@ void test_cpp_utf8 ()
+       /* 111122223456
+         Byte columns.  */
+ 
+-    ASSERT_EQ (5, cpp_display_width (str, 6, def_tabstop));
++    ASSERT_EQ (5, cpp_display_width (str, 6, policy));
+     ASSERT_EQ (105,
+-              cpp_byte_column_to_display_column (str, 6, 106, def_tabstop));
++              cpp_byte_column_to_display_column (str, 6, 106, policy));
+     ASSERT_EQ (10000,
+-              cpp_byte_column_to_display_column (NULL, 0, 10000, def_tabstop));
++              cpp_byte_column_to_display_column (NULL, 0, 10000, policy));
+     ASSERT_EQ (0,
+-              cpp_byte_column_to_display_column (NULL, 10000, 0, def_tabstop));
++              cpp_byte_column_to_display_column (NULL, 10000, 0, policy));
+   }
+ 
+   /* Verify that cpp_display_column_to_byte_column can go past the end,
+@@ -3678,25 +3686,25 @@ void test_cpp_utf8 ()
+       /* 000000000000000000000000000000000111111
+         111122223333444456666777788889999012345
+         Byte columns.  */
+-    ASSERT_EQ (4, cpp_display_column_to_byte_column (str, 15, 2, def_tabstop));
++    ASSERT_EQ (4, cpp_display_column_to_byte_column (str, 15, 2, policy));
+     ASSERT_EQ (15,
+-              cpp_display_column_to_byte_column (str, 15, 11, def_tabstop));
++              cpp_display_column_to_byte_column (str, 15, 11, policy));
+     ASSERT_EQ (115,
+-              cpp_display_column_to_byte_column (str, 15, 111, def_tabstop));
++              cpp_display_column_to_byte_column (str, 15, 111, policy));
+     ASSERT_EQ (10000,
+-              cpp_display_column_to_byte_column (NULL, 0, 10000, def_tabstop));
++              cpp_display_column_to_byte_column (NULL, 0, 10000, policy));
+     ASSERT_EQ (0,
+-              cpp_display_column_to_byte_column (NULL, 10000, 0, def_tabstop));
++              cpp_display_column_to_byte_column (NULL, 10000, 0, policy));
+ 
+     /* Verify that we do not interrupt a UTF-8 sequence.  */
+-    ASSERT_EQ (4, cpp_display_column_to_byte_column (str, 15, 1, def_tabstop));
++    ASSERT_EQ (4, cpp_display_column_to_byte_column (str, 15, 1, policy));
+ 
+     for (int byte_col = 1; byte_col <= 15; ++byte_col)
+       {
+        const int disp_col
+-         = cpp_byte_column_to_display_column (str, 15, byte_col, def_tabstop);
++         = cpp_byte_column_to_display_column (str, 15, byte_col, policy);
+        const int byte_col2
+-         = cpp_display_column_to_byte_column (str, 15, disp_col, def_tabstop);
++         = cpp_display_column_to_byte_column (str, 15, disp_col, policy);
+ 
+        /* If we ask for the display column in the middle of a UTF-8
+           sequence, it will return the length of the partial sequence,
+diff --git a/gcc/input.h b/gcc/input.h
+--- a/gcc/input.h       2021-12-25 01:29:12.927317174 -0800
++++ b/gcc/input.h       2021-12-25 01:30:50.681688823 -0800
+@@ -39,8 +39,11 @@ STATIC_ASSERT (BUILTINS_LOCATION < RESER
+ extern bool is_location_from_builtin_token (location_t);
+ extern expanded_location expand_location (location_t);
+ 
+-extern int location_compute_display_column (expanded_location exploc,
+-                                           int tabstop);
++class cpp_char_column_policy;
++
++extern int
++location_compute_display_column (expanded_location exploc,
++                                const cpp_char_column_policy &policy);
+ 
+ /* A class capturing the bounds of a buffer, to allow for run-time
+    bounds-checking in a checked build.  */
+diff --git a/gcc/opts.c b/gcc/opts.c
+--- a/gcc/opts.c        2021-12-25 01:29:12.927317174 -0800
++++ b/gcc/opts.c        2021-12-25 01:30:50.681688823 -0800
+@@ -2447,6 +2447,10 @@ common_handle_option (struct gcc_options
+       dc->column_origin = value;
+       break;
+ 
++    case OPT_fdiagnostics_escape_format_:
++      dc->escape_format = (enum diagnostics_escape_format)value;
++      break;
++
+     case OPT_fdiagnostics_show_cwe:
+       dc->show_cwe = value;
+       break;
+diff --git a/gcc/selftest.c b/gcc/selftest.c
+--- a/gcc/selftest.c    2020-07-22 23:35:17.820389797 -0700
++++ b/gcc/selftest.c    2021-12-25 01:30:50.681688823 -0800
+@@ -193,6 +193,21 @@ temp_source_file::temp_source_file (cons
+   fclose (out);
+ }
+ 
++/* As above, but with a size, to allow for NUL bytes in CONTENT.  */
++
++temp_source_file::temp_source_file (const location &loc,
++                                   const char *suffix,
++                                   const char *content,
++                                   size_t sz)
++: named_temp_file (suffix)
++{
++  FILE *out = fopen (get_filename (), "w");
++  if (!out)
++    fail_formatted (loc, "unable to open tempfile: %s", get_filename ());
++  fwrite (content, sz, 1, out);
++  fclose (out);
++}
++
+ /* Avoid introducing locale-specific differences in the results
+    by hardcoding open_quote and close_quote.  */
+ 
+diff --git a/gcc/selftest.h b/gcc/selftest.h
+--- a/gcc/selftest.h    2020-07-22 23:35:17.820389797 -0700
++++ b/gcc/selftest.h    2021-12-25 01:30:50.681688823 -0800
+@@ -112,6 +112,8 @@ class temp_source_file : public named_te
+  public:
+   temp_source_file (const location &loc, const char *suffix,
+                    const char *content);
++  temp_source_file (const location &loc, const char *suffix,
++                   const char *content, size_t sz);
+ };
+ 
+ /* RAII-style class for avoiding introducing locale-specific differences
+diff --git a/gcc/testsuite/c-c++-common/diagnostic-format-json-1.c b/gcc/testsuite/c-c++-common/diagnostic-format-json-1.c
+--- a/gcc/testsuite/c-c++-common/diagnostic-format-json-1.c     2021-12-25 01:29:12.927317174 -0800
++++ b/gcc/testsuite/c-c++-common/diagnostic-format-json-1.c     2021-12-25 01:30:50.681688823 -0800
+@@ -9,6 +9,7 @@
+ 
+ /* { dg-regexp "\"kind\": \"error\"" } */
+ /* { dg-regexp "\"column-origin\": 1" } */
++/* { dg-regexp "\"escape-source\": false" } */
+ /* { dg-regexp "\"message\": \"#error message\"" } */
+ 
+ /* { dg-regexp "\"caret\": \{" } */
+diff --git a/gcc/testsuite/c-c++-common/diagnostic-format-json-2.c b/gcc/testsuite/c-c++-common/diagnostic-format-json-2.c
+--- a/gcc/testsuite/c-c++-common/diagnostic-format-json-2.c     2021-12-25 01:29:12.927317174 -0800
++++ b/gcc/testsuite/c-c++-common/diagnostic-format-json-2.c     2021-12-25 01:30:50.681688823 -0800
+@@ -9,6 +9,7 @@
+ 
+ /* { dg-regexp "\"kind\": \"warning\"" } */
+ /* { dg-regexp "\"column-origin\": 1" } */
++/* { dg-regexp "\"escape-source\": false" } */
+ /* { dg-regexp "\"message\": \"#warning message\"" } */
+ /* { dg-regexp "\"option\": \"-Wcpp\"" } */
+ /* { dg-regexp "\"option_url\": \"https:\[^\n\r\"\]*#index-Wcpp\"" } */
+diff --git a/gcc/testsuite/c-c++-common/diagnostic-format-json-3.c b/gcc/testsuite/c-c++-common/diagnostic-format-json-3.c
+--- a/gcc/testsuite/c-c++-common/diagnostic-format-json-3.c     2021-12-25 01:29:12.927317174 -0800
++++ b/gcc/testsuite/c-c++-common/diagnostic-format-json-3.c     2021-12-25 01:30:50.681688823 -0800
+@@ -9,6 +9,7 @@
+ 
+ /* { dg-regexp "\"kind\": \"error\"" } */
+ /* { dg-regexp "\"column-origin\": 1" } */
++/* { dg-regexp "\"escape-source\": false" } */
+ /* { dg-regexp "\"message\": \"#warning message\"" } */
+ /* { dg-regexp "\"option\": \"-Werror=cpp\"" } */
+ /* { dg-regexp "\"option_url\": \"https:\[^\n\r\"\]*#index-Wcpp\"" } */
+diff --git a/gcc/testsuite/c-c++-common/diagnostic-format-json-4.c b/gcc/testsuite/c-c++-common/diagnostic-format-json-4.c
+--- a/gcc/testsuite/c-c++-common/diagnostic-format-json-4.c     2021-12-25 01:29:12.927317174 -0800
++++ b/gcc/testsuite/c-c++-common/diagnostic-format-json-4.c     2021-12-25 01:30:50.681688823 -0800
+@@ -19,6 +19,7 @@ int test (void)
+ 
+ /* { dg-regexp "\"kind\": \"note\"" } */
+ /* { dg-regexp "\"message\": \"...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'\"" } */
++/* { dg-regexp "\"escape-source\": false" } */
+ 
+ /* { dg-regexp "\"caret\": \{" } */
+ /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-4.c\"" } */
+@@ -39,6 +40,7 @@ int test (void)
+ /* { dg-regexp "\"kind\": \"warning\"" } */
+ /* { dg-regexp "\"column-origin\": 1" } */
+ /* { dg-regexp "\"message\": \"this 'if' clause does not guard...\"" } */
++/* { dg-regexp "\"escape-source\": false" } */
+ /* { dg-regexp "\"option\": \"-Wmisleading-indentation\"" } */
+ /* { dg-regexp "\"option_url\": \"https:\[^\n\r\"\]*#index-Wmisleading-indentation\"" } */
+ 
+diff --git a/gcc/testsuite/c-c++-common/diagnostic-format-json-5.c b/gcc/testsuite/c-c++-common/diagnostic-format-json-5.c
+--- a/gcc/testsuite/c-c++-common/diagnostic-format-json-5.c     2021-12-25 01:29:12.927317174 -0800
++++ b/gcc/testsuite/c-c++-common/diagnostic-format-json-5.c     2021-12-25 01:30:50.681688823 -0800
+@@ -14,6 +14,7 @@ int test (struct s *ptr)
+ 
+ /* { dg-regexp "\"kind\": \"error\"" } */
+ /* { dg-regexp "\"column-origin\": 1" } */
++/* { dg-regexp "\"escape-source\": false" } */
+ /* { dg-regexp "\"message\": \".*\"" } */
+ 
+ /* Verify fix-it hints.  */
+diff --git a/gcc/testsuite/gcc.dg/cpp/warn-normalized-4-bytes.c b/gcc/testsuite/gcc.dg/cpp/warn-normalized-4-bytes.c
+--- a/gcc/testsuite/gcc.dg/cpp/warn-normalized-4-bytes.c        1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/gcc.dg/cpp/warn-normalized-4-bytes.c        2021-12-25 01:30:50.681688823 -0800
+@@ -0,0 +1,21 @@
++// { dg-do preprocess }
++// { dg-options "-std=gnu99 -Werror=normalized=nfc -fdiagnostics-show-caret -fdiagnostics-escape-format=bytes" }
++/* { dg-message "some warnings being treated as errors" "" {target "*-*-*"} 0 } */
++
++/* འ= U+0F43 TIBETAN LETTER GHA, which has decomposition "0F42 0FB7" i.e.
++   U+0F42 TIBETAN LETTER GA: à½
++   U+0FB7 TIBETAN SUBJOINED LETTER HA: ྷ
++
++   The UTF-8 encoding of U+0F43 TIBETAN LETTER GHA is: E0 BD 83.  */
++
++foo before_\u0F43_after bar // { dg-error "`before_.U00000f43_after' is not in NFC .-Werror=normalized=." }
++/* { dg-begin-multiline-output "" }
++ foo before_\u0F43_after bar
++     ^~~~~~~~~~~~~~~~~~~
++   { dg-end-multiline-output "" } */
++
++foo before_à½_after bar // { dg-error "`before_.U00000f43_after' is not in NFC .-Werror=normalized=." }
++/* { dg-begin-multiline-output "" }
++ foo before_<e0><bd><83>_after bar
++     ^~~~~~~~~~~~~~~~~~~~~~~~~
++   { dg-end-multiline-output "" } */
+diff --git a/gcc/testsuite/gcc.dg/cpp/warn-normalized-4-unicode.c b/gcc/testsuite/gcc.dg/cpp/warn-normalized-4-unicode.c
+--- a/gcc/testsuite/gcc.dg/cpp/warn-normalized-4-unicode.c      1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/gcc.dg/cpp/warn-normalized-4-unicode.c      2021-12-25 01:30:50.681688823 -0800
+@@ -0,0 +1,19 @@
++// { dg-do preprocess }
++// { dg-options "-std=gnu99 -Werror=normalized=nfc -fdiagnostics-show-caret -fdiagnostics-escape-format=unicode" }
++/* { dg-message "some warnings being treated as errors" "" {target "*-*-*"} 0 } */
++
++/* འ= U+0F43 TIBETAN LETTER GHA, which has decomposition "0F42 0FB7" i.e.
++   U+0F42 TIBETAN LETTER GA: à½
++   U+0FB7 TIBETAN SUBJOINED LETTER HA: ྷ  */
++
++foo before_\u0F43_after bar  // { dg-error "`before_.U00000f43_after' is not in NFC .-Werror=normalized=." }
++/* { dg-begin-multiline-output "" }
++ foo before_\u0F43_after bar
++     ^~~~~~~~~~~~~~~~~~~
++   { dg-end-multiline-output "" } */
++
++foo before_à½_after bar // { dg-error "`before_.U00000f43_after' is not in NFC .-Werror=normalized=." }
++/* { dg-begin-multiline-output "" }
++ foo before_<U+0F43>_after bar
++     ^~~~~~~~~~~~~~~~~~~~~
++   { dg-end-multiline-output "" } */
+diff --git a/gcc/testsuite/gfortran.dg/diagnostic-format-json-1.F90 b/gcc/testsuite/gfortran.dg/diagnostic-format-json-1.F90
+--- a/gcc/testsuite/gfortran.dg/diagnostic-format-json-1.F90    2021-12-25 01:29:12.931317107 -0800
++++ b/gcc/testsuite/gfortran.dg/diagnostic-format-json-1.F90    2021-12-25 01:30:50.681688823 -0800
+@@ -9,6 +9,7 @@
+ 
+ ! { dg-regexp "\"kind\": \"error\"" }
+ ! { dg-regexp "\"column-origin\": 1" }
++! { dg-regexp "\"escape-source\": false" }
+ ! { dg-regexp "\"message\": \"#error message\"" }
+ 
+ ! { dg-regexp "\"caret\": \{" }
+diff --git a/gcc/testsuite/gfortran.dg/diagnostic-format-json-2.F90 b/gcc/testsuite/gfortran.dg/diagnostic-format-json-2.F90
+--- a/gcc/testsuite/gfortran.dg/diagnostic-format-json-2.F90    2021-12-25 01:29:12.931317107 -0800
++++ b/gcc/testsuite/gfortran.dg/diagnostic-format-json-2.F90    2021-12-25 01:30:50.681688823 -0800
+@@ -9,6 +9,7 @@
+ 
+ ! { dg-regexp "\"kind\": \"warning\"" }
+ ! { dg-regexp "\"column-origin\": 1" }
++! { dg-regexp "\"escape-source\": false" }
+ ! { dg-regexp "\"message\": \"#warning message\"" }
+ ! { dg-regexp "\"option\": \"-Wcpp\"" }
+ ! { dg-regexp "\"option_url\": \"\[^\n\r\"\]*#index-Wcpp\"" }
+diff --git a/gcc/testsuite/gfortran.dg/diagnostic-format-json-3.F90 b/gcc/testsuite/gfortran.dg/diagnostic-format-json-3.F90
+--- a/gcc/testsuite/gfortran.dg/diagnostic-format-json-3.F90    2021-12-25 01:29:12.931317107 -0800
++++ b/gcc/testsuite/gfortran.dg/diagnostic-format-json-3.F90    2021-12-25 01:30:50.681688823 -0800
+@@ -9,6 +9,7 @@
+ 
+ ! { dg-regexp "\"kind\": \"error\"" }
+ ! { dg-regexp "\"column-origin\": 1" }
++! { dg-regexp "\"escape-source\": false" }
+ ! { dg-regexp "\"message\": \"#warning message\"" }
+ ! { dg-regexp "\"option\": \"-Werror=cpp\"" }
+ ! { dg-regexp "\"option_url\": \"\[^\n\r\"\]*#index-Wcpp\"" }
+diff --git a/libcpp/charset.c b/libcpp/charset.c
+--- a/libcpp/charset.c  2021-12-25 01:29:12.931317107 -0800
++++ b/libcpp/charset.c  2021-12-25 01:30:50.681688823 -0800
+@@ -1549,12 +1549,14 @@ convert_escape (cpp_reader *pfile, const
+                   "unknown escape sequence: '\\%c'", (int) c);
+       else
+        {
++         encoding_rich_location rich_loc (pfile);
++
+          /* diagnostic.c does not support "%03o".  When it does, this
+             code can use %03o directly in the diagnostic again.  */
+          char buf[32];
+          sprintf(buf, "%03o", (int) c);
+-         cpp_error (pfile, CPP_DL_PEDWARN,
+-                    "unknown escape sequence: '\\%s'", buf);
++         cpp_error_at (pfile, CPP_DL_PEDWARN, &rich_loc,
++                       "unknown escape sequence: '\\%s'", buf);
+        }
+     }
+ 
+@@ -2277,14 +2279,16 @@ cpp_string_location_reader::get_next ()
+ }
+ 
+ cpp_display_width_computation::
+-cpp_display_width_computation (const char *data, int data_length, int tabstop) :
++cpp_display_width_computation (const char *data, int data_length,
++                              const cpp_char_column_policy &policy) :
+   m_begin (data),
+   m_next (m_begin),
+   m_bytes_left (data_length),
+-  m_tabstop (tabstop),
++  m_policy (policy),
+   m_display_cols (0)
+ {
+-  gcc_assert (m_tabstop > 0);
++  gcc_assert (policy.m_tabstop > 0);
++  gcc_assert (policy.m_width_cb);
+ }
+ 
+ 
+@@ -2296,19 +2300,28 @@ cpp_display_width_computation (const cha
+    point to a valid UTF-8-encoded sequence, then it will be treated as a single
+    byte with display width 1.  m_cur_display_col is the current display column,
+    relative to which tab stops should be expanded.  Returns the display width of
+-   the codepoint just processed.  */
++   the codepoint just processed.
++   If OUT is non-NULL, it is populated.  */
+ 
+ int
+-cpp_display_width_computation::process_next_codepoint ()
++cpp_display_width_computation::process_next_codepoint (cpp_decoded_char *out)
+ {
+   cppchar_t c;
+   int next_width;
+ 
++  if (out)
++    out->m_start_byte = m_next;
++
+   if (*m_next == '\t')
+     {
+       ++m_next;
+       --m_bytes_left;
+-      next_width = m_tabstop - (m_display_cols % m_tabstop);
++      next_width = m_policy.m_tabstop - (m_display_cols % m_policy.m_tabstop);
++      if (out)
++       {
++         out->m_ch = '\t';
++         out->m_valid_ch = true;
++       }
+     }
+   else if (one_utf8_to_cppchar ((const uchar **) &m_next, &m_bytes_left, &c)
+           != 0)
+@@ -2318,14 +2331,24 @@ cpp_display_width_computation::process_n
+         of one.  */
+       ++m_next;
+       --m_bytes_left;
+-      next_width = 1;
++      next_width = m_policy.m_undecoded_byte_width;
++      if (out)
++       out->m_valid_ch = false;
+     }
+   else
+     {
+       /*  one_utf8_to_cppchar() has updated m_next and m_bytes_left for us.  */
+-      next_width = cpp_wcwidth (c);
++      next_width = m_policy.m_width_cb (c);
++      if (out)
++       {
++         out->m_ch = c;
++         out->m_valid_ch = true;
++       }
+     }
+ 
++  if (out)
++    out->m_next_byte = m_next;
++
+   m_display_cols += next_width;
+   return next_width;
+ }
+@@ -2341,7 +2364,7 @@ cpp_display_width_computation::advance_d
+   const int start = m_display_cols;
+   const int target = start + n;
+   while (m_display_cols < target && !done ())
+-    process_next_codepoint ();
++    process_next_codepoint (NULL);
+   return m_display_cols - start;
+ }
+ 
+@@ -2349,29 +2372,33 @@ cpp_display_width_computation::advance_d
+     how many display columns are occupied by the first COLUMN bytes.  COLUMN
+     may exceed DATA_LENGTH, in which case the phantom bytes at the end are
+     treated as if they have display width 1.  Tabs are expanded to the next tab
+-    stop, relative to the start of DATA.  */
++    stop, relative to the start of DATA, and non-printable-ASCII characters
++    will be escaped as per POLICY.  */
+ 
+ int
+ cpp_byte_column_to_display_column (const char *data, int data_length,
+-                                  int column, int tabstop)
++                                  int column,
++                                  const cpp_char_column_policy &policy)
+ {
+   const int offset = MAX (0, column - data_length);
+-  cpp_display_width_computation dw (data, column - offset, tabstop);
++  cpp_display_width_computation dw (data, column - offset, policy);
+   while (!dw.done ())
+-    dw.process_next_codepoint ();
++    dw.process_next_codepoint (NULL);
+   return dw.display_cols_processed () + offset;
+ }
+ 
+ /*  For the string of length DATA_LENGTH bytes that begins at DATA, compute
+     the least number of bytes that will result in at least DISPLAY_COL display
+     columns.  The return value may exceed DATA_LENGTH if the entire string does
+-    not occupy enough display columns.  */
++    not occupy enough display columns.  Non-printable-ASCII characters
++    will be escaped as per POLICY.  */
+ 
+ int
+ cpp_display_column_to_byte_column (const char *data, int data_length,
+-                                  int display_col, int tabstop)
++                                  int display_col,
++                                  const cpp_char_column_policy &policy)
+ {
+-  cpp_display_width_computation dw (data, data_length, tabstop);
++  cpp_display_width_computation dw (data, data_length, policy);
+   const int avail_display = dw.advance_display_cols (display_col);
+   return dw.bytes_processed () + MAX (0, display_col - avail_display);
+ }
+diff --git a/libcpp/errors.c b/libcpp/errors.c
+--- a/libcpp/errors.c   2020-07-22 23:35:18.712399623 -0700
++++ b/libcpp/errors.c   2021-12-25 01:30:50.681688823 -0800
+@@ -27,6 +27,31 @@ along with this program; see the file CO
+ #include "cpplib.h"
+ #include "internal.h"
+ 
++/* Get a location_t for the current location in PFILE,
++   generally that of the previously lexed token.  */
++
++location_t
++cpp_diagnostic_get_current_location (cpp_reader *pfile)
++{
++  if (CPP_OPTION (pfile, traditional))
++    {
++      if (pfile->state.in_directive)
++       return pfile->directive_line;
++      else
++       return pfile->line_table->highest_line;
++    }
++  /* We don't want to refer to a token before the beginning of the
++     current run -- that is invalid.  */
++  else if (pfile->cur_token == pfile->cur_run->base)
++    {
++      return 0;
++    }
++  else
++    {
++      return pfile->cur_token[-1].src_loc;
++    }
++}
++
+ /* Print a diagnostic at the given location.  */
+ 
+ ATTRIBUTE_FPTR_PRINTF(5,0)
+@@ -52,25 +77,7 @@ cpp_diagnostic (cpp_reader * pfile, enum
+                enum cpp_warning_reason reason,
+                const char *msgid, va_list *ap)
+ {
+-  location_t src_loc;
+-
+-  if (CPP_OPTION (pfile, traditional))
+-    {
+-      if (pfile->state.in_directive)
+-       src_loc = pfile->directive_line;
+-      else
+-       src_loc = pfile->line_table->highest_line;
+-    }
+-  /* We don't want to refer to a token before the beginning of the
+-     current run -- that is invalid.  */
+-  else if (pfile->cur_token == pfile->cur_run->base)
+-    {
+-      src_loc = 0;
+-    }
+-  else
+-    {
+-      src_loc = pfile->cur_token[-1].src_loc;
+-    }
++  location_t src_loc = cpp_diagnostic_get_current_location (pfile);
+   rich_location richloc (pfile->line_table, src_loc);
+   return cpp_diagnostic_at (pfile, level, reason, &richloc, msgid, ap);
+ }
+@@ -142,6 +149,43 @@ cpp_warning_syshdr (cpp_reader * pfile,
+ 
+   va_end (ap);
+   return ret;
++}
++
++/* As cpp_warning above, but use RICHLOC as the location of the diagnostic.  */
++
++bool cpp_warning_at (cpp_reader *pfile, enum cpp_warning_reason reason,
++                    rich_location *richloc, const char *msgid, ...)
++{
++  va_list ap;
++  bool ret;
++
++  va_start (ap, msgid);
++
++  ret = cpp_diagnostic_at (pfile, CPP_DL_WARNING, reason, richloc,
++                          msgid, &ap);
++
++  va_end (ap);
++  return ret;
++
++}
++
++/* As cpp_pedwarning above, but use RICHLOC as the location of the
++   diagnostic.  */
++
++bool
++cpp_pedwarning_at (cpp_reader * pfile, enum cpp_warning_reason reason,
++                  rich_location *richloc, const char *msgid, ...)
++{
++  va_list ap;
++  bool ret;
++
++  va_start (ap, msgid);
++
++  ret = cpp_diagnostic_at (pfile, CPP_DL_PEDWARN, reason, richloc,
++                          msgid, &ap);
++
++  va_end (ap);
++  return ret;
+ }
+ 
+ /* Print a diagnostic at a specific location.  */
+diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h
+--- a/libcpp/include/cpplib.h   2021-12-25 01:29:12.931317107 -0800
++++ b/libcpp/include/cpplib.h   2021-12-25 01:30:50.685688757 -0800
+@@ -1176,6 +1176,14 @@ extern bool cpp_warning_syshdr (cpp_read
+                                const char *msgid, ...)
+   ATTRIBUTE_PRINTF_3;
+ 
++/* As their counterparts above, but use RICHLOC.  */
++extern bool cpp_warning_at (cpp_reader *, enum cpp_warning_reason,
++                           rich_location *richloc, const char *msgid, ...)
++  ATTRIBUTE_PRINTF_4;
++extern bool cpp_pedwarning_at (cpp_reader *, enum cpp_warning_reason,
++                              rich_location *richloc, const char *msgid, ...)
++  ATTRIBUTE_PRINTF_4;
++
+ /* Output a diagnostic with "MSGID: " preceding the
+    error string of errno.  No location is printed.  */
+ extern bool cpp_errno (cpp_reader *, enum cpp_diagnostic_level,
+@@ -1320,42 +1328,95 @@ extern const char * cpp_get_userdef_suff
+ 
+ /* In charset.c */
+ 
++/* The result of attempting to decode a run of UTF-8 bytes.  */
++
++struct cpp_decoded_char
++{
++  const char *m_start_byte;
++  const char *m_next_byte;
++
++  bool m_valid_ch;
++  cppchar_t m_ch;
++};
++
++/* Information for mapping between code points and display columns.
++
++   This is a tabstop value, along with a callback for getting the
++   widths of characters.  Normally this callback is cpp_wcwidth, but we
++   support other schemes for escaping non-ASCII unicode as a series of
++   ASCII chars when printing the user's source code in diagnostic-show-locus.c
++
++   For example, consider:
++   - the Unicode character U+03C0 "GREEK SMALL LETTER PI" (UTF-8: 0xCF 0x80)
++   - the Unicode character U+1F642 "SLIGHTLY SMILING FACE"
++     (UTF-8: 0xF0 0x9F 0x99 0x82)
++   - the byte 0xBF (a stray trailing byte of a UTF-8 character)
++   Normally U+03C0 would occupy one display column, U+1F642
++   would occupy two display columns, and the stray byte would be
++   printed verbatim as one display column.
++
++   However when escaping them as unicode code points as "<U+03C0>"
++   and "<U+1F642>" they occupy 8 and 9 display columns respectively,
++   and when escaping them as bytes as "<CF><80>" and "<F0><9F><99><82>"
++   they occupy 8 and 16 display columns respectively.  In both cases
++   the stray byte is escaped to <BF> as 4 display columns.  */
++
++struct cpp_char_column_policy
++{
++  cpp_char_column_policy (int tabstop,
++                         int (*width_cb) (cppchar_t c))
++  : m_tabstop (tabstop),
++    m_undecoded_byte_width (1),
++    m_width_cb (width_cb)
++  {}
++
++  int m_tabstop;
++  /* Width in display columns of a stray byte that isn't decodable
++     as UTF-8.  */
++  int m_undecoded_byte_width;
++  int (*m_width_cb) (cppchar_t c);
++};
++
+ /* A class to manage the state while converting a UTF-8 sequence to cppchar_t
+    and computing the display width one character at a time.  */
+ class cpp_display_width_computation {
+  public:
+   cpp_display_width_computation (const char *data, int data_length,
+-                                int tabstop);
++                                const cpp_char_column_policy &policy);
+   const char *next_byte () const { return m_next; }
+   int bytes_processed () const { return m_next - m_begin; }
+   int bytes_left () const { return m_bytes_left; }
+   bool done () const { return !bytes_left (); }
+   int display_cols_processed () const { return m_display_cols; }
+ 
+-  int process_next_codepoint ();
++  int process_next_codepoint (cpp_decoded_char *out);
+   int advance_display_cols (int n);
+ 
+  private:
+   const char *const m_begin;
+   const char *m_next;
+   size_t m_bytes_left;
+-  const int m_tabstop;
++  const cpp_char_column_policy &m_policy;
+   int m_display_cols;
+ };
+ 
+ /* Convenience functions that are simple use cases for class
+    cpp_display_width_computation.  Tab characters will be expanded to spaces
+-   as determined by TABSTOP.  */
++   as determined by POLICY.m_tabstop, and non-printable-ASCII characters
++   will be escaped as per POLICY.  */
++
+ int cpp_byte_column_to_display_column (const char *data, int data_length,
+-                                      int column, int tabstop);
++                                      int column,
++                                      const cpp_char_column_policy &policy);
+ inline int cpp_display_width (const char *data, int data_length,
+-                             int tabstop)
++                             const cpp_char_column_policy &policy)
+ {
+   return cpp_byte_column_to_display_column (data, data_length, data_length,
+-                                           tabstop);
++                                           policy);
+ }
+ int cpp_display_column_to_byte_column (const char *data, int data_length,
+-                                      int display_col, int tabstop);
++                                      int display_col,
++                                      const cpp_char_column_policy &policy);
+ int cpp_wcwidth (cppchar_t c);
+ 
+ #endif /* ! LIBCPP_CPPLIB_H */
+diff --git a/libcpp/include/line-map.h b/libcpp/include/line-map.h
+--- a/libcpp/include/line-map.h 2020-07-22 23:35:18.712399623 -0700
++++ b/libcpp/include/line-map.h 2021-12-25 01:30:50.685688757 -0800
+@@ -1732,6 +1732,18 @@ class rich_location
+   const diagnostic_path *get_path () const { return m_path; }
+   void set_path (const diagnostic_path *path) { m_path = path; }
+ 
++  /* A flag for hinting that the diagnostic involves character encoding
++     issues, and thus that it will be helpful to the user if we show some
++     representation of how the characters in the pertinent source lines
++     are encoded.
++     The default is false (i.e. do not escape).
++     When set to true, non-ASCII bytes in the pertinent source lines will
++     be escaped in a manner controlled by the user-supplied option
++     -fdiagnostics-escape-format=, so that the user can better understand
++     what's going on with the encoding in their source file.  */
++  bool escape_on_output_p () const { return m_escape_on_output; }
++  void set_escape_on_output (bool flag) { m_escape_on_output = flag; }
++
+ private:
+   bool reject_impossible_fixit (location_t where);
+   void stop_supporting_fixits ();
+@@ -1758,6 +1770,7 @@ protected:
+   bool m_fixits_cannot_be_auto_applied;
+ 
+   const diagnostic_path *m_path;
++  bool m_escape_on_output;
+ };
+ 
+ /* A struct for the result of range_label::get_text: a NUL-terminated buffer
+diff --git a/libcpp/internal.h b/libcpp/internal.h
+--- a/libcpp/internal.h 2020-07-22 23:35:18.712399623 -0700
++++ b/libcpp/internal.h 2021-12-25 01:30:50.685688757 -0800
+@@ -758,6 +758,9 @@ struct _cpp_dir_only_callbacks
+ extern void _cpp_preprocess_dir_only (cpp_reader *,
+                                      const struct _cpp_dir_only_callbacks *);
+ 
++/* In errors.c  */
++extern location_t cpp_diagnostic_get_current_location (cpp_reader *);
++
+ /* In traditional.c.  */
+ extern bool _cpp_scan_out_logical_line (cpp_reader *, cpp_macro *, bool);
+ extern bool _cpp_read_logical_line_trad (cpp_reader *);
+@@ -946,6 +949,26 @@ int linemap_get_expansion_line (class li
+ const char* linemap_get_expansion_filename (class line_maps *,
+                                            location_t);
+ 
++/* A subclass of rich_location for emitting a diagnostic
++   at the current location of the reader, but flagging
++   it with set_escape_on_output (true).  */
++class encoding_rich_location : public rich_location
++{
++ public:
++  encoding_rich_location (cpp_reader *pfile)
++  : rich_location (pfile->line_table,
++                  cpp_diagnostic_get_current_location (pfile))
++  {
++    set_escape_on_output (true);
++  }
++
++  encoding_rich_location (cpp_reader *pfile, location_t loc)
++  : rich_location (pfile->line_table, loc)
++  {
++    set_escape_on_output (true);
++  }
++};
++
+ #ifdef __cplusplus
+ }
+ #endif
+diff --git a/libcpp/lex.c b/libcpp/lex.c
+--- a/libcpp/lex.c      2021-12-24 20:23:45.568762024 -0800
++++ b/libcpp/lex.c      2021-12-25 01:30:50.685688757 -0800
+@@ -1268,7 +1268,11 @@ skip_whitespace (cpp_reader *pfile, cppc
+   while (is_nvspace (c));
+ 
+   if (saw_NUL)
+-    cpp_error (pfile, CPP_DL_WARNING, "null character(s) ignored");
++    {
++      encoding_rich_location rich_loc (pfile);
++      cpp_error_at (pfile, CPP_DL_WARNING, &rich_loc,
++                   "null character(s) ignored");
++    }
+ 
+   buffer->cur--;
+ }
+@@ -1297,6 +1301,28 @@ warn_about_normalization (cpp_reader *pf
+   if (CPP_OPTION (pfile, warn_normalize) < NORMALIZE_STATE_RESULT (s)
+       && !pfile->state.skipping)
+     {
++      location_t loc = token->src_loc;
++
++      /* If possible, create a location range for the token.  */
++      if (loc >= RESERVED_LOCATION_COUNT
++         && token->type != CPP_EOF
++         /* There must be no line notes to process.  */
++         && (!(pfile->buffer->cur
++               >= pfile->buffer->notes[pfile->buffer->cur_note].pos
++               && !pfile->overlaid_buffer)))
++       {
++         source_range tok_range;
++         tok_range.m_start = loc;
++         tok_range.m_finish
++           = linemap_position_for_column (pfile->line_table,
++                                          CPP_BUF_COLUMN (pfile->buffer,
++                                                          pfile->buffer->cur));
++         loc = COMBINE_LOCATION_DATA (pfile->line_table,
++                                      loc, tok_range, NULL);
++       }
++
++      encoding_rich_location rich_loc (pfile, loc);
++
+       /* Make sure that the token is printed using UCNs, even
+         if we'd otherwise happily print UTF-8.  */
+       unsigned char *buf = XNEWVEC (unsigned char, cpp_token_len (token));
+@@ -1304,11 +1330,11 @@ warn_about_normalization (cpp_reader *pf
+ 
+       sz = cpp_spell_token (pfile, token, buf, false) - buf;
+       if (NORMALIZE_STATE_RESULT (s) == normalized_C)
+-       cpp_warning_with_line (pfile, CPP_W_NORMALIZE, token->src_loc, 0,
+-                              "`%.*s' is not in NFKC", (int) sz, buf);
++       cpp_warning_at (pfile, CPP_W_NORMALIZE, &rich_loc,
++                       "`%.*s' is not in NFKC", (int) sz, buf);
+       else
+-       cpp_warning_with_line (pfile, CPP_W_NORMALIZE, token->src_loc, 0,
+-                              "`%.*s' is not in NFC", (int) sz, buf);
++       cpp_warning_at (pfile, CPP_W_NORMALIZE, &rich_loc,
++                       "`%.*s' is not in NFC", (int) sz, buf);
+       free (buf);
+     }
+ }
+diff --git a/libcpp/line-map.c b/libcpp/line-map.c
+--- a/libcpp/line-map.c 2020-07-22 23:35:18.712399623 -0700
++++ b/libcpp/line-map.c 2021-12-25 01:30:50.685688757 -0800
+@@ -2007,7 +2007,8 @@ rich_location::rich_location (line_maps
+   m_fixit_hints (),
+   m_seen_impossible_fixit (false),
+   m_fixits_cannot_be_auto_applied (false),
+-  m_path (NULL)
++  m_path (NULL),
++  m_escape_on_output (false)
+ {
+   add_range (loc, SHOW_RANGE_WITH_CARET, label);
+ }
diff --git a/meta/recipes-devtools/gcc/gcc/0003-CVE-2021-42574.patch b/meta/recipes-devtools/gcc/gcc/0003-CVE-2021-42574.patch
new file mode 100644
index 0000000000..6bfaf8402d
--- /dev/null
+++ b/meta/recipes-devtools/gcc/gcc/0003-CVE-2021-42574.patch
@@ -0,0 +1,1724 @@
+From 51c500269bf53749b107807d84271385fad35628 Mon Sep 17 00:00:00 2001
+From: Marek Polacek <polacek@redhat.com>
+Date: Wed, 6 Oct 2021 14:33:59 -0400
+Subject: [PATCH] libcpp: Implement -Wbidi-chars for CVE-2021-42574 [PR103026]
+
+From a link below:
+"An issue was discovered in the Bidirectional Algorithm in the Unicode
+Specification through 14.0. It permits the visual reordering of
+characters via control sequences, which can be used to craft source code
+that renders different logic than the logical ordering of tokens
+ingested by compilers and interpreters. Adversaries can leverage this to
+encode source code for compilers accepting Unicode such that targeted
+vulnerabilities are introduced invisibly to human reviewers."
+
+More info:
+https://nvd.nist.gov/vuln/detail/CVE-2021-42574
+https://trojansource.codes/
+
+This is not a compiler bug.  However, to mitigate the problem, this patch
+implements -Wbidi-chars=[none|unpaired|any] to warn about possibly
+misleading Unicode bidirectional control characters the preprocessor may
+encounter.
+
+The default is =unpaired, which warns about improperly terminated
+bidirectional control characters; e.g. a LRE without its corresponding PDF.
+The level =any warns about any use of bidirectional control characters.
+
+This patch handles both UCNs and UTF-8 characters.  UCNs designating
+bidi characters in identifiers are accepted since r204886.  Then r217144
+enabled -fextended-identifiers by default.  Extended characters in C/C++
+identifiers have been accepted since r275979.  However, this patch still
+warns about mixing UTF-8 and UCN bidi characters; there seems to be no
+good reason to allow mixing them.
+
+We warn in different contexts: comments (both C and C++-style), string
+literals, character constants, and identifiers.  Expectedly, UCNs are ignored
+in comments and raw string literals.  The bidirectional control characters
+can nest so this patch handles that as well.
+
+I have not included nor tested this at all with Fortran (which also has
+string literals and line comments).
+
+Dave M. posted patches improving diagnostic involving Unicode characters.
+This patch does not make use of this new infrastructure yet.
+
+        PR preprocessor/103026
+
+gcc/c-family/ChangeLog:
+
+        * c.opt (Wbidi-chars, Wbidi-chars=): New option.
+
+gcc/ChangeLog:
+
+        * doc/invoke.texi: Document -Wbidi-chars.
+
+libcpp/ChangeLog:
+
+        * include/cpplib.h (enum cpp_bidirectional_level): New.
+        (struct cpp_options): Add cpp_warn_bidirectional.
+        (enum cpp_warning_reason): Add CPP_W_BIDIRECTIONAL.
+        * internal.h (struct cpp_reader): Add warn_bidi_p member
+        function.
+        * init.c (cpp_create_reader): Set cpp_warn_bidirectional.
+        * lex.c (bidi): New namespace.
+        (get_bidi_utf8): New function.
+        (get_bidi_ucn): Likewise.
+        (maybe_warn_bidi_on_close): Likewise.
+        (maybe_warn_bidi_on_char): Likewise.
+        (_cpp_skip_block_comment): Implement warning about bidirectional
+        control characters.
+        (skip_line_comment): Likewise.
+        (forms_identifier_p): Likewise.
+        (lex_identifier): Likewise.
+        (lex_string): Likewise.
+        (lex_raw_string): Likewise.
+
+gcc/testsuite/ChangeLog:
+
+        * c-c++-common/Wbidi-chars-1.c: New test.
+        * c-c++-common/Wbidi-chars-2.c: New test.
+        * c-c++-common/Wbidi-chars-3.c: New test.
+        * c-c++-common/Wbidi-chars-4.c: New test.
+        * c-c++-common/Wbidi-chars-5.c: New test.
+        * c-c++-common/Wbidi-chars-6.c: New test.
+        * c-c++-common/Wbidi-chars-7.c: New test.
+        * c-c++-common/Wbidi-chars-8.c: New test.
+        * c-c++-common/Wbidi-chars-9.c: New test.
+        * c-c++-common/Wbidi-chars-10.c: New test.
+        * c-c++-common/Wbidi-chars-11.c: New test.
+        * c-c++-common/Wbidi-chars-12.c: New test.
+        * c-c++-common/Wbidi-chars-13.c: New test.
+        * c-c++-common/Wbidi-chars-14.c: New test.
+        * c-c++-common/Wbidi-chars-15.c: New test.
+        * c-c++-common/Wbidi-chars-16.c: New test.
+        * c-c++-common/Wbidi-chars-17.c: New test.
+
+CVE: CVE-2021-42574
+Upstream-Status: Backport [https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=51c500269bf53749b107807d84271385fad35628]
+Signed-off-by: Pgowda <pgowda.cve@gmail.com>
+
+---
+ gcc/c-family/c.opt                          |  24 ++
+ gcc/doc/invoke.texi                         |  21 +-
+ gcc/testsuite/c-c++-common/Wbidi-chars-1.c  |  12 +
+ gcc/testsuite/c-c++-common/Wbidi-chars-10.c |  27 ++
+ gcc/testsuite/c-c++-common/Wbidi-chars-11.c |  13 +
+ gcc/testsuite/c-c++-common/Wbidi-chars-12.c |  19 +
+ gcc/testsuite/c-c++-common/Wbidi-chars-13.c |  17 +
+ gcc/testsuite/c-c++-common/Wbidi-chars-14.c |  38 ++
+ gcc/testsuite/c-c++-common/Wbidi-chars-15.c |  59 +++
+ gcc/testsuite/c-c++-common/Wbidi-chars-16.c |  26 ++
+ gcc/testsuite/c-c++-common/Wbidi-chars-17.c |  30 ++
+ gcc/testsuite/c-c++-common/Wbidi-chars-2.c  |   9 +
+ gcc/testsuite/c-c++-common/Wbidi-chars-3.c  |  11 +
+ gcc/testsuite/c-c++-common/Wbidi-chars-4.c  | 188 +++++++++
+ gcc/testsuite/c-c++-common/Wbidi-chars-5.c  | 188 +++++++++
+ gcc/testsuite/c-c++-common/Wbidi-chars-6.c  | 155 ++++++++
+ gcc/testsuite/c-c++-common/Wbidi-chars-7.c  |   9 +
+ gcc/testsuite/c-c++-common/Wbidi-chars-8.c  |  13 +
+ gcc/testsuite/c-c++-common/Wbidi-chars-9.c  |  29 ++
+ libcpp/include/cpplib.h                     |  18 +-
+ libcpp/init.c                               |   1 +
+ libcpp/internal.h                           |   7 +
+ libcpp/lex.c                                | 408 +++++++++++++++++++-
+ 23 files changed, 1315 insertions(+), 7 deletions(-)
+ create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-1.c
+ create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-10.c
+ create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-11.c
+ create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-12.c
+ create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-13.c
+ create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-14.c
+ create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-15.c
+ create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-16.c
+ create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-17.c
+ create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-2.c
+ create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-3.c
+ create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-4.c
+ create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-5.c
+ create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-6.c
+ create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-7.c
+ create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-8.c
+ create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-9.c
+
+diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
+--- a/gcc/c-family/c.opt        2021-12-25 01:29:12.915317374 -0800
++++ b/gcc/c-family/c.opt        2021-12-25 01:36:22.040018701 -0800
+@@ -350,6 +350,30 @@ Wbad-function-cast
+ C ObjC Var(warn_bad_function_cast) Warning
+ Warn about casting functions to incompatible types.
+ 
++Wbidi-chars
++C ObjC C++ ObjC++ Warning Alias(Wbidi-chars=,any,none)
++;
++
++Wbidi-chars=
++C ObjC C++ ObjC++ RejectNegative Joined Warning CPP(cpp_warn_bidirectional) CppReason(CPP_W_BIDIRECTIONAL) Var(warn_bidirectional) Init(bidirectional_unpaired) Enum(cpp_bidirectional_level)
++-Wbidi-chars=[none|unpaired|any] Warn about UTF-8 bidirectional control characters.
++
++; Required for these enum values.
++SourceInclude
++cpplib.h
++
++Enum
++Name(cpp_bidirectional_level) Type(int) UnknownError(argument %qs to %<-Wbidi-chars%> not recognized)
++
++EnumValue
++Enum(cpp_bidirectional_level) String(none) Value(bidirectional_none)
++
++EnumValue
++Enum(cpp_bidirectional_level) String(unpaired) Value(bidirectional_unpaired)
++
++EnumValue
++Enum(cpp_bidirectional_level) String(any) Value(bidirectional_any)
++
+ Wbool-compare
+ C ObjC C++ ObjC++ Var(warn_bool_compare) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
+ Warn about boolean expression compared with an integer value different from true/false.
+diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
+--- a/gcc/doc/invoke.texi       2021-12-25 01:35:33.284883488 -0800
++++ b/gcc/doc/invoke.texi       2021-12-25 01:36:22.048018559 -0800
+@@ -310,7 +310,9 @@ Objective-C and Objective-C++ Dialects}.
+ -Warith-conversion @gol
+ -Warray-bounds  -Warray-bounds=@var{n} @gol
+ -Wno-attributes  -Wattribute-alias=@var{n} -Wno-attribute-alias @gol
+--Wno-attribute-warning  -Wbool-compare  -Wbool-operation @gol
++-Wno-attribute-warning  @gol
++-Wbidi-chars=@r{[}none@r{|}unpaired@r{|}any@r{]} @gol
++-Wbool-compare  -Wbool-operation @gol
+ -Wno-builtin-declaration-mismatch @gol
+ -Wno-builtin-macro-redefined  -Wc90-c99-compat  -Wc99-c11-compat @gol
+ -Wc11-c2x-compat @gol
+@@ -6860,6 +6862,23 @@ Attributes considered include @code{allo
+ This is the default.  You can disable these warnings with either
+ @option{-Wno-attribute-alias} or @option{-Wattribute-alias=0}.
+ 
++@item -Wbidi-chars=@r{[}none@r{|}unpaired@r{|}any@r{]}
++@opindex Wbidi-chars=
++@opindex Wbidi-chars
++@opindex Wno-bidi-chars
++Warn about possibly misleading UTF-8 bidirectional control characters in
++comments, string literals, character constants, and identifiers.  Such
++characters can change left-to-right writing direction into right-to-left
++(and vice versa), which can cause confusion between the logical order and
++visual order.  This may be dangerous; for instance, it may seem that a piece
++of code is not commented out, whereas it in fact is.
++
++There are three levels of warning supported by GCC@.  The default is
++@option{-Wbidi-chars=unpaired}, which warns about improperly terminated
++bidi contexts.  @option{-Wbidi-chars=none} turns the warning off.
++@option{-Wbidi-chars=any} warns about any use of bidirectional control
++characters.
++
+ @item -Wbool-compare
+ @opindex Wno-bool-compare
+ @opindex Wbool-compare
+diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-10.c b/gcc/testsuite/c-c++-common/Wbidi-chars-10.c
+--- a/gcc/testsuite/c-c++-common/Wbidi-chars-10.c       1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-10.c       2021-12-25 01:36:22.048018559 -0800
+@@ -0,0 +1,27 @@
++/* PR preprocessor/103026 */
++/* { dg-do compile } */
++/* { dg-options "-Wbidi-chars=unpaired" } */
++/* More nesting testing.  */
++
++/* RLE‫ LRI⁦ PDF‬ PDI⁩*/
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int LRE_\u202a_PDF_\u202c;
++int LRE_\u202a_PDF_\u202c_LRE_\u202a_PDF_\u202c;
++int LRE_\u202a_LRI_\u2066_PDF_\u202c_PDI_\u2069;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int RLE_\u202b_RLI_\u2067_PDF_\u202c_PDI_\u2069;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int RLE_\u202b_RLI_\u2067_PDI_\u2069_PDF_\u202c;
++int FSI_\u2068_LRO_\u202d_PDI_\u2069_PDF_\u202c;
++int FSI_\u2068;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int FSI_\u2068_PDI_\u2069;
++int FSI_\u2068_FSI_\u2068_PDI_\u2069;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI_\u2067_PDI_\u2069_PDI_\u2069_PDI_\u2069_PDI_\u2069_PDI_\u2069_PDI_\u2069_PDI_\u2069;
++int RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI_\u2067_PDI_\u2069_PDI_\u2069_PDI_\u2069_PDI_\u2069_PDI_\u2069_PDI_\u2069;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI_\u2067_PDI_\u2069_PDI_\u2069_PDI_\u2069_PDI_\u2069_PDI_\u2069_PDI_\u2069_PDF_\u202c;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI_\u2067_FSI_\u2068_PDI_\u2069_PDI_\u2069_PDI_\u2069_PDI_\u2069;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
+diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-11.c b/gcc/testsuite/c-c++-common/Wbidi-chars-11.c
+--- a/gcc/testsuite/c-c++-common/Wbidi-chars-11.c       1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-11.c       2021-12-25 01:36:22.048018559 -0800
+@@ -0,0 +1,13 @@
++/* PR preprocessor/103026 */
++/* { dg-do compile } */
++/* { dg-options "-Wbidi-chars=unpaired" } */
++/* Test that we warn when mixing UCN and UTF-8.  */
++
++int LRE_‪_PDF_\u202c;
++/* { dg-warning "mismatch" "" { target *-*-* } .-1 } */
++int LRE_\u202a_PDF_‬_;
++/* { dg-warning "mismatch" "" { target *-*-* } .-1 } */
++const char *s1 = "LRE_‪_PDF_\u202c";
++/* { dg-warning "mismatch" "" { target *-*-* } .-1 } */
++const char *s2 = "LRE_\u202a_PDF_‬";
++/* { dg-warning "mismatch" "" { target *-*-* } .-1 } */
+diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-12.c b/gcc/testsuite/c-c++-common/Wbidi-chars-12.c
+--- a/gcc/testsuite/c-c++-common/Wbidi-chars-12.c       1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-12.c       2021-12-25 01:36:22.048018559 -0800
+@@ -0,0 +1,19 @@
++/* PR preprocessor/103026 */
++/* { dg-do compile { target { c || c++11 } } } */
++/* { dg-options "-Wbidi-chars=any" } */
++/* Test raw strings.  */
++
++const char *s1 = R"(a b c LRE‪ 1 2 3 PDF‬ x y z)";
++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
++const char *s2 = R"(a b c RLE‫ 1 2 3 PDF‬ x y z)";
++/* { dg-warning "U\\+202B" "" { target *-*-* } .-1 } */
++const char *s3 = R"(a b c LRO‭ 1 2 3 PDF‬ x y z)";
++/* { dg-warning "U\\+202D" "" { target *-*-* } .-1 } */
++const char *s4 = R"(a b c RLO‮ 1 2 3 PDF‬ x y z)";
++/* { dg-warning "U\\+202E" "" { target *-*-* } .-1 } */
++const char *s7 = R"(a b c FSI⁨ 1 2 3 PDI⁩ x y) z";
++/* { dg-warning "U\\+2068" "" { target *-*-* } .-1 } */
++const char *s8 = R"(a b c PDI⁩ x y )z";
++/* { dg-warning "U\\+2069" "" { target *-*-* } .-1 } */
++const char *s9 = R"(a b c PDF‬ x y z)";
++/* { dg-warning "U\\+202C" "" { target *-*-* } .-1 } */
+diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-13.c b/gcc/testsuite/c-c++-common/Wbidi-chars-13.c
+--- a/gcc/testsuite/c-c++-common/Wbidi-chars-13.c       1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-13.c       2021-12-25 01:36:22.048018559 -0800
+@@ -0,0 +1,17 @@
++/* PR preprocessor/103026 */
++/* { dg-do compile { target { c || c++11 } } } */
++/* { dg-options "-Wbidi-chars=unpaired" } */
++/* Test raw strings.  */
++
++const char *s1 = R"(a b c LRE‪ 1 2 3)";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++const char *s2 = R"(a b c RLE‫ 1 2 3)";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++const char *s3 = R"(a b c LRO‭ 1 2 3)";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++const char *s4 = R"(a b c FSI⁨ 1 2 3)";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++const char *s5 = R"(a b c LRI⁦ 1 2 3)";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++const char *s6 = R"(a b c RLI⁧ 1 2 3)";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
+diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-14.c b/gcc/testsuite/c-c++-common/Wbidi-chars-14.c
+--- a/gcc/testsuite/c-c++-common/Wbidi-chars-14.c       1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-14.c       2021-12-25 01:36:22.048018559 -0800
+@@ -0,0 +1,38 @@
++/* PR preprocessor/103026 */
++/* { dg-do compile } */
++/* { dg-options "-Wbidi-chars=unpaired" } */
++/* Test PDI handling, which also pops any subsequent LREs, RLEs, LROs,
++   or RLOs.  */
++
++/* LRI_⁦_LRI_⁦_RLE_‫_RLE_‫_RLE_‫_PDI_⁩*/
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++// LRI_⁦_RLE_‫_RLE_‫_RLE_‫_PDI_⁩
++// LRI_⁦_RLO_‮_RLE_‫_RLE_‫_PDI_⁩
++// LRI_⁦_RLO_‮_RLE_‫_PDI_⁩
++// FSI_⁨_RLO_‮_PDI_⁩
++// FSI_⁨_FSI_⁨_RLO_‮_PDI_⁩
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++
++int LRI_\u2066_LRI_\u2066_LRE_\u202a_LRE_\u202a_LRE_\u202a_PDI_\u2069;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int LRI_\u2066_LRI_\u2066_LRE_\u202a_LRE_\u202a_LRE_\u202a_PDI_\u2069_PDI_\u2069;
++int LRI_\u2066_LRI_\u2066_LRI_\u2066_LRE_\u202a_LRE_\u202a_LRE_\u202a_PDI_\u2069_PDI_\u2069;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int PDI_\u2069;
++int LRI_\u2066_PDI_\u2069;
++int RLI_\u2067_PDI_\u2069;
++int LRE_\u202a_LRI_\u2066_PDI_\u2069;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int LRI_\u2066_LRE_\u202a_PDF_\u202c_PDI_\u2069;
++int LRI_\u2066_LRE_\u202a_LRE_\u202a_PDF_\u202c_PDI_\u2069;
++int RLI_\u2067_LRI_\u2066_LRE_\u202a_LRE_\u202a_PDF_\u202c_PDI_\u2069;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int FSI_\u2068_LRI_\u2066_LRE_\u202a_LRE_\u202a_PDF_\u202c_PDI_\u2069;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int RLO_\u202e_PDI_\u2069;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int RLI_\u2067_PDI_\u2069_RLI_\u2067;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int FSI_\u2068_PDF_\u202c_PDI_\u2069;
++int FSI_\u2068_FSI_\u2068_PDF_\u202c_PDI_\u2069;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
+diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-15.c b/gcc/testsuite/c-c++-common/Wbidi-chars-15.c
+--- a/gcc/testsuite/c-c++-common/Wbidi-chars-15.c       1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-15.c       2021-12-25 01:36:22.048018559 -0800
+@@ -0,0 +1,59 @@
++/* PR preprocessor/103026 */
++/* { dg-do compile } */
++/* { dg-options "-Wbidi-chars=unpaired" } */
++/* Test unpaired bidi control chars in multiline comments.  */
++
++/*
++ * LRE‪ end
++ */
++/* { dg-warning "unpaired" "" { target *-*-* } .-2 } */
++/*
++ * RLE‫ end
++ */
++/* { dg-warning "unpaired" "" { target *-*-* } .-2 } */
++/*
++ * LRO‭ end
++ */
++/* { dg-warning "unpaired" "" { target *-*-* } .-2 } */
++/*
++ * RLO‮ end
++ */
++/* { dg-warning "unpaired" "" { target *-*-* } .-2 } */
++/*
++ * LRI⁦ end
++ */
++/* { dg-warning "unpaired" "" { target *-*-* } .-2 } */
++/*
++ * RLI⁧ end
++ */
++/* { dg-warning "unpaired" "" { target *-*-* } .-2 } */
++/*
++ * FSI⁨ end
++ */
++/* { dg-warning "unpaired" "" { target *-*-* } .-2 } */
++/* LRE‪
++   PDF‬ */
++/* { dg-warning "unpaired" "" { target *-*-* } .-2 } */
++/* FSI⁨
++   PDI⁩ */
++/* { dg-warning "unpaired" "" { target *-*-* } .-2 } */
++
++/* LRE<‪>
++ *
++ */
++/* { dg-warning "unpaired" "" { target *-*-* } .-3 } */
++
++/*
++ * LRE<‪>
++ */
++/* { dg-warning "unpaired" "" { target *-*-* } .-2 } */
++
++/*
++ *
++ * LRE<‪> */
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++
++/* RLI<⁧> */ /* PDI<⁩> */
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++/* LRE<‪> */ /* PDF<‬> */
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
+diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-16.c b/gcc/testsuite/c-c++-common/Wbidi-chars-16.c
+--- a/gcc/testsuite/c-c++-common/Wbidi-chars-16.c       1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-16.c       2021-12-25 01:36:22.048018559 -0800
+@@ -0,0 +1,26 @@
++/* PR preprocessor/103026 */
++/* { dg-do compile } */
++/* { dg-options "-Wbidi-chars=any" } */
++/* Test LTR/RTL chars.  */
++
++/* LTR<‎> */
++/* { dg-warning "U\\+200E" "" { target *-*-* } .-1 } */
++// LTR<‎>
++/* { dg-warning "U\\+200E" "" { target *-*-* } .-1 } */
++/* RTL<‏> */
++/* { dg-warning "U\\+200F" "" { target *-*-* } .-1 } */
++// RTL<‏>
++/* { dg-warning "U\\+200F" "" { target *-*-* } .-1 } */
++
++const char *s1 = "LTR<‎>";
++/* { dg-warning "U\\+200E" "" { target *-*-* } .-1 } */
++const char *s2 = "LTR\u200e";
++/* { dg-warning "U\\+200E" "" { target *-*-* } .-1 } */
++const char *s3 = "LTR\u200E";
++/* { dg-warning "U\\+200E" "" { target *-*-* } .-1 } */
++const char *s4 = "RTL<‏>";
++/* { dg-warning "U\\+200F" "" { target *-*-* } .-1 } */
++const char *s5 = "RTL\u200f";
++/* { dg-warning "U\\+200F" "" { target *-*-* } .-1 } */
++const char *s6 = "RTL\u200F";
++/* { dg-warning "U\\+200F" "" { target *-*-* } .-1 } */
+diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-17.c b/gcc/testsuite/c-c++-common/Wbidi-chars-17.c
+--- a/gcc/testsuite/c-c++-common/Wbidi-chars-17.c       1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-17.c       2021-12-25 01:36:22.048018559 -0800
+@@ -0,0 +1,30 @@
++/* PR preprocessor/103026 */
++/* { dg-do compile } */
++/* { dg-options "-Wbidi-chars=unpaired" } */
++/* Test LTR/RTL chars.  */
++
++/* LTR<‎> */
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++// LTR<‎>
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++/* RTL<‏> */
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++// RTL<‏>
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++int ltr_\u200e;
++/* { dg-error "universal character " "" { target *-*-* } .-1 } */
++int rtl_\u200f;
++/* { dg-error "universal character " "" { target *-*-* } .-1 } */
++
++const char *s1 = "LTR<‎>";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++const char *s2 = "LTR\u200e";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++const char *s3 = "LTR\u200E";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++const char *s4 = "RTL<‏>";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++const char *s5 = "RTL\u200f";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++const char *s6 = "RTL\u200F";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
+diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-1.c b/gcc/testsuite/c-c++-common/Wbidi-chars-1.c
+--- a/gcc/testsuite/c-c++-common/Wbidi-chars-1.c        1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-1.c        2021-12-25 01:36:22.048018559 -0800
+@@ -0,0 +1,12 @@
++/* PR preprocessor/103026 */
++/* { dg-do compile } */
++
++int main() {
++    int isAdmin = 0;
++    /*‮ } ⁦if (isAdmin)⁩ ⁦ begin admins only */
++/* { dg-warning "bidirectional" "" { target *-*-* } .-1 } */
++        __builtin_printf("You are an admin.\n");
++    /* end admins only ‮ { ⁦*/
++/* { dg-warning "bidirectional" "" { target *-*-* } .-1 } */
++    return 0;
++}
+diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-2.c b/gcc/testsuite/c-c++-common/Wbidi-chars-2.c
+--- a/gcc/testsuite/c-c++-common/Wbidi-chars-2.c        1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-2.c        2021-12-25 01:36:22.048018559 -0800
+@@ -0,0 +1,9 @@
++/* PR preprocessor/103026 */
++/* { dg-do compile } */
++
++int main() {
++    /* Say hello; newline⁧/*/ return 0 ;
++/* { dg-warning "bidirectional" "" { target *-*-* } .-1 } */
++    __builtin_printf("Hello world.\n");
++    return 0;
++}
+diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-3.c b/gcc/testsuite/c-c++-common/Wbidi-chars-3.c
+--- a/gcc/testsuite/c-c++-common/Wbidi-chars-3.c        1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-3.c        2021-12-25 01:36:22.048018559 -0800
+@@ -0,0 +1,11 @@
++/* PR preprocessor/103026 */
++/* { dg-do compile } */
++
++int main() {
++    const char* access_level = "user";
++    if (__builtin_strcmp(access_level, "user‮ ⁦// Check if admin⁩ ⁦")) {
++/* { dg-warning "bidirectional" "" { target *-*-* } .-1 } */
++        __builtin_printf("You are an admin.\n");
++    }
++    return 0;
++}
+diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-4.c b/gcc/testsuite/c-c++-common/Wbidi-chars-4.c
+--- a/gcc/testsuite/c-c++-common/Wbidi-chars-4.c        1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-4.c        2021-12-25 01:36:22.048018559 -0800
+@@ -0,0 +1,188 @@
++/* PR preprocessor/103026 */
++/* { dg-do compile } */
++/* { dg-options "-Wbidi-chars=any -Wno-multichar -Wno-overflow" } */
++/* Test all bidi chars in various contexts (identifiers, comments,
++   string literals, character constants), both UCN and UTF-8.  The bidi
++   chars here are properly terminated, except for the character constants.  */
++
++/* a b c LRE‪ 1 2 3 PDF‬ x y z */
++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
++/* a b c RLE‫ 1 2 3 PDF‬ x y z */
++/* { dg-warning "U\\+202B" "" { target *-*-* } .-1 } */
++/* a b c LRO‭ 1 2 3 PDF‬ x y z */
++/* { dg-warning "U\\+202D" "" { target *-*-* } .-1 } */
++/* a b c RLO‮ 1 2 3 PDF‬ x y z */
++/* { dg-warning "U\\+202E" "" { target *-*-* } .-1 } */
++/* a b c LRI⁦ 1 2 3 PDI⁩ x y z */
++/* { dg-warning "U\\+2066" "" { target *-*-* } .-1 } */
++/* a b c RLI⁧ 1 2 3 PDI⁩ x y */
++/* { dg-warning "U\\+2067" "" { target *-*-* } .-1 } */
++/* a b c FSI⁨ 1 2 3 PDI⁩ x y z */
++/* { dg-warning "U\\+2068" "" { target *-*-* } .-1 } */
++
++/* Same but C++ comments instead.  */
++// a b c LRE‪ 1 2 3 PDF‬ x y z
++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
++// a b c RLE‫ 1 2 3 PDF‬ x y z
++/* { dg-warning "U\\+202B" "" { target *-*-* } .-1 } */
++// a b c LRO‭ 1 2 3 PDF‬ x y z
++/* { dg-warning "U\\+202D" "" { target *-*-* } .-1 } */
++// a b c RLO‮ 1 2 3 PDF‬ x y z
++/* { dg-warning "U\\+202E" "" { target *-*-* } .-1 } */
++// a b c LRI⁦ 1 2 3 PDI⁩ x y z
++/* { dg-warning "U\\+2066" "" { target *-*-* } .-1 } */
++// a b c RLI⁧ 1 2 3 PDI⁩ x y
++/* { dg-warning "U\\+2067" "" { target *-*-* } .-1 } */
++// a b c FSI⁨ 1 2 3 PDI⁩ x y z
++/* { dg-warning "U\\+2068" "" { target *-*-* } .-1 } */
++
++/* Here we're closing an unopened context, warn when =any.  */
++/* a b c PDI⁩ x y z */
++/* { dg-warning "U\\+2069" "" { target *-*-* } .-1 } */
++/* a b c PDF‬ x y z */
++/* { dg-warning "U\\+202C" "" { target *-*-* } .-1 } */
++// a b c PDI⁩ x y z
++/* { dg-warning "U\\+2069" "" { target *-*-* } .-1 } */
++// a b c PDF‬ x y z
++/* { dg-warning "U\\+202C" "" { target *-*-* } .-1 } */
++
++/* Multiline comments.  */
++/* a b c PDI⁩ x y z
++   */
++/* { dg-warning "U\\+2069" "" { target *-*-* } .-2 } */
++/* a b c PDF‬ x y z
++   */
++/* { dg-warning "U\\+202C" "" { target *-*-* } .-2 } */
++/* first
++   a b c PDI⁩ x y z
++   */
++/* { dg-warning "U\\+2069" "" { target *-*-* } .-2 } */
++/* first
++   a b c PDF‬ x y z
++   */
++/* { dg-warning "U\\+202C" "" { target *-*-* } .-2 } */
++/* first
++   a b c PDI⁩ x y z */
++/* { dg-warning "U\\+2069" "" { target *-*-* } .-1 } */
++/* first
++   a b c PDF‬ x y z */
++/* { dg-warning "U\\+202C" "" { target *-*-* } .-1 } */
++
++void
++g1 ()
++{
++  const char *s1 = "a b c LRE‪ 1 2 3 PDF‬ x y z";
++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
++  const char *s2 = "a b c RLE‫ 1 2 3 PDF‬ x y z";
++/* { dg-warning "U\\+202B" "" { target *-*-* } .-1 } */
++  const char *s3 = "a b c LRO‭ 1 2 3 PDF‬ x y z";
++/* { dg-warning "U\\+202D" "" { target *-*-* } .-1 } */
++  const char *s4 = "a b c RLO‮ 1 2 3 PDF‬ x y z";
++/* { dg-warning "U\\+202E" "" { target *-*-* } .-1 } */
++  const char *s5 = "a b c LRI⁦ 1 2 3 PDI⁩ x y z";
++/* { dg-warning "U\\+2066" "" { target *-*-* } .-1 } */
++  const char *s6 = "a b c RLI⁧ 1 2 3 PDI⁩ x y z";
++/* { dg-warning "U\\+2067" "" { target *-*-* } .-1 } */
++  const char *s7 = "a b c FSI⁨ 1 2 3 PDI⁩ x y z";
++/* { dg-warning "U\\+2068" "" { target *-*-* } .-1 } */
++  const char *s8 = "a b c PDI⁩ x y z";
++/* { dg-warning "U\\+2069" "" { target *-*-* } .-1 } */
++  const char *s9 = "a b c PDF‬ x y z";
++/* { dg-warning "U\\+202C" "" { target *-*-* } .-1 } */
++
++  const char *s10 = "a b c LRE\u202a 1 2 3 PDF\u202c x y z";
++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
++  const char *s11 = "a b c LRE\u202A 1 2 3 PDF\u202c x y z";
++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
++  const char *s12 = "a b c RLE\u202b 1 2 3 PDF\u202c x y z";
++/* { dg-warning "U\\+202B" "" { target *-*-* } .-1 } */
++  const char *s13 = "a b c RLE\u202B 1 2 3 PDF\u202c x y z";
++/* { dg-warning "U\\+202B" "" { target *-*-* } .-1 } */
++  const char *s14 = "a b c LRO\u202d 1 2 3 PDF\u202c x y z";
++/* { dg-warning "U\\+202D" "" { target *-*-* } .-1 } */
++  const char *s15 = "a b c LRO\u202D 1 2 3 PDF\u202c x y z";
++/* { dg-warning "U\\+202D" "" { target *-*-* } .-1 } */
++  const char *s16 = "a b c RLO\u202e 1 2 3 PDF\u202c x y z";
++/* { dg-warning "U\\+202E" "" { target *-*-* } .-1 } */
++  const char *s17 = "a b c RLO\u202E 1 2 3 PDF\u202c x y z";
++/* { dg-warning "U\\+202E" "" { target *-*-* } .-1 } */
++  const char *s18 = "a b c LRI\u2066 1 2 3 PDI\u2069 x y z";
++/* { dg-warning "U\\+2066" "" { target *-*-* } .-1 } */
++  const char *s19 = "a b c RLI\u2067 1 2 3 PDI\u2069 x y z";
++/* { dg-warning "U\\+2067" "" { target *-*-* } .-1 } */
++  const char *s20 = "a b c FSI\u2068 1 2 3 PDI\u2069 x y z";
++/* { dg-warning "U\\+2068" "" { target *-*-* } .-1 } */
++}
++
++void
++g2 ()
++{
++  const char c1 = '\u202a';
++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
++  const char c2 = '\u202A';
++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
++  const char c3 = '\u202b';
++/* { dg-warning "U\\+202B" "" { target *-*-* } .-1 } */
++  const char c4 = '\u202B';
++/* { dg-warning "U\\+202B" "" { target *-*-* } .-1 } */
++  const char c5 = '\u202d';
++/* { dg-warning "U\\+202D" "" { target *-*-* } .-1 } */
++  const char c6 = '\u202D';
++/* { dg-warning "U\\+202D" "" { target *-*-* } .-1 } */
++  const char c7 = '\u202e';
++/* { dg-warning "U\\+202E" "" { target *-*-* } .-1 } */
++  const char c8 = '\u202E';
++/* { dg-warning "U\\+202E" "" { target *-*-* } .-1 } */
++  const char c9 = '\u2066';
++/* { dg-warning "U\\+2066" "" { target *-*-* } .-1 } */
++  const char c10 = '\u2067';
++/* { dg-warning "U\\+2067" "" { target *-*-* } .-1 } */
++  const char c11 = '\u2068';
++/* { dg-warning "U\\+2068" "" { target *-*-* } .-1 } */
++}
++
++int a‪b‬c;
++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
++int a‫b‬c;
++/* { dg-warning "U\\+202B" "" { target *-*-* } .-1 } */
++int a‭b‬c;
++/* { dg-warning "U\\+202D" "" { target *-*-* } .-1 } */
++int a‮b‬c;
++/* { dg-warning "U\\+202E" "" { target *-*-* } .-1 } */
++int a⁦b⁩c;
++/* { dg-warning "U\\+2066" "" { target *-*-* } .-1 } */
++int a⁧b⁩c;
++/* { dg-warning "U\\+2067" "" { target *-*-* } .-1 } */
++int a⁨b⁩c;
++/* { dg-warning "U\\+2068" "" { target *-*-* } .-1 } */
++int A‬X;
++/* { dg-warning "U\\+202C" "" { target *-*-* } .-1 } */
++int A\u202cY;
++/* { dg-warning "U\\+202C" "" { target *-*-* } .-1 } */
++int A\u202CY2;
++/* { dg-warning "U\\+202C" "" { target *-*-* } .-1 } */
++
++int d\u202ae\u202cf;
++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
++int d\u202Ae\u202cf2;
++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
++int d\u202be\u202cf;
++/* { dg-warning "U\\+202B" "" { target *-*-* } .-1 } */
++int d\u202Be\u202cf2;
++/* { dg-warning "U\\+202B" "" { target *-*-* } .-1 } */
++int d\u202de\u202cf;
++/* { dg-warning "U\\+202D" "" { target *-*-* } .-1 } */
++int d\u202De\u202cf2;
++/* { dg-warning "U\\+202D" "" { target *-*-* } .-1 } */
++int d\u202ee\u202cf;
++/* { dg-warning "U\\+202E" "" { target *-*-* } .-1 } */
++int d\u202Ee\u202cf2;
++/* { dg-warning "U\\+202E" "" { target *-*-* } .-1 } */
++int d\u2066e\u2069f;
++/* { dg-warning "U\\+2066" "" { target *-*-* } .-1 } */
++int d\u2067e\u2069f;
++/* { dg-warning "U\\+2067" "" { target *-*-* } .-1 } */
++int d\u2068e\u2069f;
++/* { dg-warning "U\\+2068" "" { target *-*-* } .-1 } */
++int X\u2069;
++/* { dg-warning "U\\+2069" "" { target *-*-* } .-1 } */
+diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-5.c b/gcc/testsuite/c-c++-common/Wbidi-chars-5.c
+--- a/gcc/testsuite/c-c++-common/Wbidi-chars-5.c        1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-5.c        2021-12-25 01:36:22.048018559 -0800
+@@ -0,0 +1,188 @@
++/* PR preprocessor/103026 */
++/* { dg-do compile } */
++/* { dg-options "-Wbidi-chars=unpaired -Wno-multichar -Wno-overflow" } */
++/* Test all bidi chars in various contexts (identifiers, comments,
++   string literals, character constants), both UCN and UTF-8.  The bidi
++   chars here are properly terminated, except for the character constants.  */
++
++/* a b c LRE‪ 1 2 3 PDF‬ x y z */
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++/* a b c RLE‫ 1 2 3 PDF‬ x y z */
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++/* a b c LRO‭ 1 2 3 PDF‬ x y z */
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++/* a b c RLO‮ 1 2 3 PDF‬ x y z */
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++/* a b c LRI⁦ 1 2 3 PDI⁩ x y z */
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++/* a b c RLI⁧ 1 2 3 PDI⁩ x y */
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++/* a b c FSI⁨ 1 2 3 PDI⁩ x y z */
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++
++/* Same but C++ comments instead.  */
++// a b c LRE‪ 1 2 3 PDF‬ x y z
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++// a b c RLE‫ 1 2 3 PDF‬ x y z
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++// a b c LRO‭ 1 2 3 PDF‬ x y z
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++// a b c RLO‮ 1 2 3 PDF‬ x y z
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++// a b c LRI⁦ 1 2 3 PDI⁩ x y z
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++// a b c RLI⁧ 1 2 3 PDI⁩ x y
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++// a b c FSI⁨ 1 2 3 PDI⁩ x y z
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++
++/* Here we're closing an unopened context, warn when =any.  */
++/* a b c PDI⁩ x y z */
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++/* a b c PDF‬ x y z */
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++// a b c PDI⁩ x y z
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++// a b c PDF‬ x y z
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++
++/* Multiline comments.  */
++/* a b c PDI⁩ x y z
++   */
++/* { dg-bogus "unpaired" "" { target *-*-* } .-2 } */
++/* a b c PDF‬ x y z
++   */
++/* { dg-bogus "unpaired" "" { target *-*-* } .-2 } */
++/* first
++   a b c PDI⁩ x y z
++   */
++/* { dg-bogus "unpaired" "" { target *-*-* } .-2 } */
++/* first
++   a b c PDF‬ x y z
++   */
++/* { dg-bogus "unpaired" "" { target *-*-* } .-2 } */
++/* first
++   a b c PDI⁩ x y z */
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++/* first
++   a b c PDF‬ x y z */
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++
++void
++g1 ()
++{
++  const char *s1 = "a b c LRE‪ 1 2 3 PDF‬ x y z";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++  const char *s2 = "a b c RLE‫ 1 2 3 PDF‬ x y z";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++  const char *s3 = "a b c LRO‭ 1 2 3 PDF‬ x y z";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++  const char *s4 = "a b c RLO‮ 1 2 3 PDF‬ x y z";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++  const char *s5 = "a b c LRI⁦ 1 2 3 PDI⁩ x y z";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++  const char *s6 = "a b c RLI⁧ 1 2 3 PDI⁩ x y z";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++  const char *s7 = "a b c FSI⁨ 1 2 3 PDI⁩ x y z";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++  const char *s8 = "a b c PDI⁩ x y z";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++  const char *s9 = "a b c PDF‬ x y z";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++
++  const char *s10 = "a b c LRE\u202a 1 2 3 PDF\u202c x y z";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++  const char *s11 = "a b c LRE\u202A 1 2 3 PDF\u202c x y z";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++  const char *s12 = "a b c RLE\u202b 1 2 3 PDF\u202c x y z";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++  const char *s13 = "a b c RLE\u202B 1 2 3 PDF\u202c x y z";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++  const char *s14 = "a b c LRO\u202d 1 2 3 PDF\u202c x y z";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++  const char *s15 = "a b c LRO\u202D 1 2 3 PDF\u202c x y z";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++  const char *s16 = "a b c RLO\u202e 1 2 3 PDF\u202c x y z";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++  const char *s17 = "a b c RLO\u202E 1 2 3 PDF\u202c x y z";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++  const char *s18 = "a b c LRI\u2066 1 2 3 PDI\u2069 x y z";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++  const char *s19 = "a b c RLI\u2067 1 2 3 PDI\u2069 x y z";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++  const char *s20 = "a b c FSI\u2068 1 2 3 PDI\u2069 x y z";
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++}
++
++void
++g2 ()
++{
++  const char c1 = '\u202a';
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char c2 = '\u202A';
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char c3 = '\u202b';
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char c4 = '\u202B';
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char c5 = '\u202d';
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char c6 = '\u202D';
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char c7 = '\u202e';
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char c8 = '\u202E';
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char c9 = '\u2066';
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char c10 = '\u2067';
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char c11 = '\u2068';
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++}
++
++int a‪b‬c;
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++int a‫b‬c;
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++int a‭b‬c;
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++int a‮b‬c;
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++int a⁦b⁩c;
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++int a⁧b⁩c;
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++int a⁨b⁩c;
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++int A‬X;
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++int A\u202cY;
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++int A\u202CY2;
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++
++int d\u202ae\u202cf;
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++int d\u202Ae\u202cf2;
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++int d\u202be\u202cf;
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++int d\u202Be\u202cf2;
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++int d\u202de\u202cf;
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++int d\u202De\u202cf2;
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++int d\u202ee\u202cf;
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++int d\u202Ee\u202cf2;
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++int d\u2066e\u2069f;
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++int d\u2067e\u2069f;
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++int d\u2068e\u2069f;
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
++int X\u2069;
++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
+diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-6.c b/gcc/testsuite/c-c++-common/Wbidi-chars-6.c
+--- a/gcc/testsuite/c-c++-common/Wbidi-chars-6.c        1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-6.c        2021-12-25 01:36:22.052018489 -0800
+@@ -0,0 +1,155 @@
++/* PR preprocessor/103026 */
++/* { dg-do compile } */
++/* { dg-options "-Wbidi-chars=unpaired" } */
++/* Test nesting of bidi chars in various contexts.  */
++
++/* Terminated by the wrong char:  */
++/* a b c LRE‪ 1 2 3 PDI⁩ x y z */
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++/* a b c RLE‫ 1 2 3 PDI⁩ x y  z*/
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++/* a b c LRO‭ 1 2 3 PDI⁩ x y z */
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++/* a b c RLO‮ 1 2 3 PDI⁩ x y z */
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++/* a b c LRI⁦ 1 2 3 PDF‬ x y z */
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++/* a b c RLI⁧ 1 2 3 PDF‬ x y z */
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++/* a b c FSI⁨ 1 2 3 PDF‬ x y  z*/
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++
++/* LRE‪ PDF‬ */
++/* LRE‪ LRE‪ PDF‬ PDF‬ */
++/* PDF‬ LRE‪ PDF‬ */
++/* LRE‪ PDF‬ LRE‪ PDF‬ */
++/* LRE‪ LRE‪ PDF‬ */
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++/* PDF‬ LRE‪ */
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++
++// a b c LRE‪ 1 2 3 PDI⁩ x y z
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++// a b c RLE‫ 1 2 3 PDI⁩ x y  z*/
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++// a b c LRO‭ 1 2 3 PDI⁩ x y z 
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++// a b c RLO‮ 1 2 3 PDI⁩ x y z 
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++// a b c LRI⁦ 1 2 3 PDF‬ x y z 
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++// a b c RLI⁧ 1 2 3 PDF‬ x y z 
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++// a b c FSI⁨ 1 2 3 PDF‬ x y  z
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++
++// LRE‪ PDF‬ 
++// LRE‪ LRE‪ PDF‬ PDF‬
++// PDF‬ LRE‪ PDF‬
++// LRE‪ PDF‬ LRE‪ PDF‬
++// LRE‪ LRE‪ PDF‬
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++// PDF‬ LRE‪
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++
++void
++g1 ()
++{
++  const char *s1 = "a b c LRE‪ 1 2 3 PDI⁩ x y z";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char *s2 = "a b c LRE\u202a 1 2 3 PDI\u2069 x y z";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char *s3 = "a b c RLE‫ 1 2 3 PDI⁩ x y ";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char *s4 = "a b c RLE\u202b 1 2 3 PDI\u2069 x y z";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char *s5 = "a b c LRO‭ 1 2 3 PDI⁩ x y z";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char *s6 = "a b c LRO\u202d 1 2 3 PDI\u2069 x y z";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char *s7 = "a b c RLO‮ 1 2 3 PDI⁩ x y z";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char *s8 = "a b c RLO\u202e 1 2 3 PDI\u2069 x y z";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char *s9 = "a b c LRI⁦ 1 2 3 PDF‬ x y z";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char *s10 = "a b c LRI\u2066 1 2 3 PDF\u202c x y z";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char *s11 = "a b c RLI⁧ 1 2 3 PDF‬ x y z\
++    ";
++/* { dg-warning "unpaired" "" { target *-*-* } .-2 } */
++  const char *s12 = "a b c RLI\u2067 1 2 3 PDF\u202c x y z";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char *s13 = "a b c FSI⁨ 1 2 3 PDF‬ x y z";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char *s14 = "a b c FSI\u2068 1 2 3 PDF\u202c x y z";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char *s15 = "PDF‬ LRE‪";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char *s16 = "PDF\u202c LRE\u202a";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char *s17 = "LRE‪ PDF‬";
++  const char *s18 = "LRE\u202a PDF\u202c";
++  const char *s19 = "LRE‪ LRE‪ PDF‬ PDF‬";
++  const char *s20 = "LRE\u202a LRE\u202a PDF\u202c PDF\u202c";
++  const char *s21 = "PDF‬ LRE‪ PDF‬";
++  const char *s22 = "PDF\u202c LRE\u202a PDF\u202c";
++  const char *s23 = "LRE‪ LRE‪ PDF‬";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char *s24 = "LRE\u202a LRE\u202a PDF\u202c";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char *s25 = "PDF‬ LRE‪";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char *s26 = "PDF\u202c LRE\u202a";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char *s27 = "PDF‬ LRE\u202a";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++  const char *s28 = "PDF\u202c LRE‪";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++}
++
++int aLRE‪bPDI⁩;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int A\u202aB\u2069C;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int aRLE‫bPDI⁩;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int a\u202bB\u2069c;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int aLRO‭bPDI⁩;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int a\u202db\u2069c2;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int aRLO‮bPDI⁩;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int a\u202eb\u2069;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int aLRI⁦bPDF‬;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int a\u2066b\u202c;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int aRLI⁧bPDF‬c
++;
++/* { dg-warning "unpaired" "" { target *-*-* } .-2 } */
++int a\u2067b\u202c;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int aFSI⁨bPDF‬;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int a\u2068b\u202c;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int aFSI⁨bPD\u202C;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int aFSI\u2068bPDF‬_;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int aLRE‪bPDF‬b; 
++int A\u202aB\u202c;
++int a_LRE‪_LRE‪_b_PDF‬_PDF‬;
++int A\u202aA\u202aB\u202cB\u202c;
++int aPDF‬bLREadPDF‬;
++int a_\u202C_\u202a_\u202c;
++int a_LRE‪_b_PDF‬_c_LRE‪_PDF‬;
++int a_\u202a_\u202c_\u202a_\u202c_;
++int a_LRE‪_b_PDF‬_c_LRE‪;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int a_\u202a_\u202c_\u202a_;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
+diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-7.c b/gcc/testsuite/c-c++-common/Wbidi-chars-7.c
+--- a/gcc/testsuite/c-c++-common/Wbidi-chars-7.c        1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-7.c        2021-12-25 01:36:22.052018489 -0800
+@@ -0,0 +1,9 @@
++/* PR preprocessor/103026 */
++/* { dg-do compile } */
++/* { dg-options "-Wbidi-chars=any" } */
++/* Test we ignore UCNs in comments.  */
++
++// a b c \u202a 1 2 3
++// a b c \u202A 1 2 3
++/* a b c \u202a 1 2 3 */
++/* a b c \u202A 1 2 3 */
+diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-8.c b/gcc/testsuite/c-c++-common/Wbidi-chars-8.c
+--- a/gcc/testsuite/c-c++-common/Wbidi-chars-8.c        1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-8.c        2021-12-25 01:36:22.052018489 -0800
+@@ -0,0 +1,13 @@
++/* PR preprocessor/103026 */
++/* { dg-do compile } */
++/* { dg-options "-Wbidi-chars=any" } */
++/* Test \u vs \U.  */
++
++int a_\u202A;
++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
++int a_\u202a_2;
++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
++int a_\U0000202A_3;
++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
++int a_\U0000202a_4;
++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
+diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-9.c b/gcc/testsuite/c-c++-common/Wbidi-chars-9.c
+--- a/gcc/testsuite/c-c++-common/Wbidi-chars-9.c        1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-9.c        2021-12-25 01:36:22.052018489 -0800
+@@ -0,0 +1,29 @@
++/* PR preprocessor/103026 */
++/* { dg-do compile } */
++/* { dg-options "-Wbidi-chars=unpaired" } */
++/* Test that we properly separate bidi contexts (comment/identifier/character
++   constant/string literal).  */
++
++/* LRE ->‪<- */ int pdf_\u202c_1;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++/* RLE ->‫<- */ int pdf_\u202c_2;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++/* LRO ->‭<- */ int pdf_\u202c_3;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++/* RLO ->‮<- */ int pdf_\u202c_4;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++/* LRI ->⁦<-*/ int pdi_\u2069_1;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++/* RLI ->⁧<- */ int pdi_\u2069_12;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++/* FSI ->⁨<- */ int pdi_\u2069_3;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++
++const char *s1 = "LRE\u202a"; /* PDF ->‬<- */
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++/* LRE ->‪<- */ const char *s2 = "PDF\u202c";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++const char *s3 = "LRE\u202a"; int pdf_\u202c_5;
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
++int lre_\u202a; const char *s4 = "PDF\u202c";
++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
+diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h
+--- a/libcpp/include/cpplib.h   2021-12-25 01:35:33.288883417 -0800
++++ b/libcpp/include/cpplib.h   2021-12-25 01:36:22.052018489 -0800
+@@ -308,6 +308,17 @@ enum cpp_normalize_level {
+   normalized_none
+ };
+ 
++/* The possible bidirectional control characters checking levels, from least
++   restrictive to most.  */
++enum cpp_bidirectional_level {
++  /* No checking.  */
++  bidirectional_none,
++  /* Only detect unpaired uses of bidirectional control characters.  */
++  bidirectional_unpaired,
++  /* Detect any use of bidirectional control characters.  */
++  bidirectional_any
++};
++
+ /* This structure is nested inside struct cpp_reader, and
+    carries all the options visible to the command line.  */
+ struct cpp_options
+@@ -515,6 +526,10 @@ struct cpp_options
+   /* True if warn about differences between C++98 and C++11.  */
+   bool cpp_warn_cxx11_compat;
+ 
++  /* Nonzero if bidirectional control characters checking is on.  See enum
++     cpp_bidirectional_level.  */
++  unsigned char cpp_warn_bidirectional;
++
+   /* Dependency generation.  */
+   struct
+   {
+@@ -613,7 +628,8 @@ enum cpp_warning_reason {
+   CPP_W_C90_C99_COMPAT,
+   CPP_W_C11_C2X_COMPAT,
+   CPP_W_CXX11_COMPAT,
+-  CPP_W_EXPANSION_TO_DEFINED
++  CPP_W_EXPANSION_TO_DEFINED,
++  CPP_W_BIDIRECTIONAL
+ };
+ 
+ /* Callback for header lookup for HEADER, which is the name of a
+diff --git a/libcpp/init.c b/libcpp/init.c
+--- a/libcpp/init.c     2021-12-25 01:29:12.931317107 -0800
++++ b/libcpp/init.c     2021-12-25 01:36:22.052018489 -0800
+@@ -215,6 +215,7 @@ cpp_create_reader (enum c_lang lang, cpp
+       = ENABLE_CANONICAL_SYSTEM_HEADERS;
+   CPP_OPTION (pfile, ext_numeric_literals) = 1;
+   CPP_OPTION (pfile, warn_date_time) = 0;
++  CPP_OPTION (pfile, cpp_warn_bidirectional) = bidirectional_unpaired;
+ 
+   /* Default CPP arithmetic to something sensible for the host for the
+      benefit of dumb users like fix-header.  */
+diff --git a/libcpp/internal.h b/libcpp/internal.h
+--- a/libcpp/internal.h 2021-12-25 01:35:33.288883417 -0800
++++ b/libcpp/internal.h 2021-12-25 01:36:22.052018489 -0800
+@@ -581,6 +581,10 @@ struct cpp_reader
+   /* If non-zero, the lexer will use this location for the next token
+      instead of getting a location from the linemap.  */
+   location_t forced_token_location;
++  bool warn_bidi_p () const
++  {
++    return CPP_OPTION (this, cpp_warn_bidirectional) != bidirectional_none;
++  }
+ };
+ 
+ /* Character classes.  Based on the more primitive macros in safe-ctype.h.
+diff --git a/libcpp/lex.c b/libcpp/lex.c
+--- a/libcpp/lex.c      2021-12-25 01:35:33.288883417 -0800
++++ b/libcpp/lex.c      2021-12-25 01:36:22.052018489 -0800
+@@ -1164,6 +1164,324 @@ _cpp_process_line_notes (cpp_reader *pfi
+     }
+ }
+ 
++namespace bidi {
++  enum class kind {
++    NONE, LRE, RLE, LRO, RLO, LRI, RLI, FSI, PDF, PDI, LTR, RTL
++  };
++
++  /* All the UTF-8 encodings of bidi characters start with E2.  */
++  constexpr uchar utf8_start = 0xe2;
++
++  /* A vector holding currently open bidi contexts.  We use a char for
++     each context, its LSB is 1 if it represents a PDF context, 0 if it
++     represents a PDI context.  The next bit is 1 if this context was open
++     by a bidi character written as a UCN, and 0 when it was UTF-8.  */
++  semi_embedded_vec <unsigned char, 16> vec;
++
++  /* Close the whole comment/identifier/string literal/character constant
++     context.  */
++  void on_close ()
++  {
++    vec.truncate (0);
++  }
++
++  /* Pop the last element in the vector.  */
++  void pop ()
++  {
++    unsigned int len = vec.count ();
++    gcc_checking_assert (len > 0);
++    vec.truncate (len - 1);
++  }
++
++  /* Return the context of the Ith element.  */
++  kind ctx_at (unsigned int i)
++  {
++    return (vec[i] & 1) ? kind::PDF : kind::PDI;
++  }
++
++  /* Return which context is currently opened.  */
++  kind current_ctx ()
++  {
++    unsigned int len = vec.count ();
++    if (len == 0)
++      return kind::NONE;
++    return ctx_at (len - 1);
++  }
++
++  /* Return true if the current context comes from a UCN origin, that is,
++     the bidi char which started this bidi context was written as a UCN.  */
++  bool current_ctx_ucn_p ()
++  {
++    unsigned int len = vec.count ();
++    gcc_checking_assert (len > 0);
++    return (vec[len - 1] >> 1) & 1;
++  }
++
++  /* We've read a bidi char, update the current vector as necessary.  */
++  void on_char (kind k, bool ucn_p)
++  {
++    switch (k)
++      {
++      case kind::LRE:
++      case kind::RLE:
++      case kind::LRO:
++      case kind::RLO:
++       vec.push (ucn_p ? 3u : 1u);
++       break;
++      case kind::LRI:
++      case kind::RLI:
++      case kind::FSI:
++       vec.push (ucn_p ? 2u : 0u);
++       break;
++      /* PDF terminates the scope of the last LRE, RLE, LRO, or RLO
++        whose scope has not yet been terminated.  */
++      case kind::PDF:
++       if (current_ctx () == kind::PDF)
++         pop ();
++       break;
++      /* PDI terminates the scope of the last LRI, RLI, or FSI whose
++        scope has not yet been terminated, as well as the scopes of
++        any subsequent LREs, RLEs, LROs, or RLOs whose scopes have not
++        yet been terminated.  */
++      case kind::PDI:
++       for (int i = vec.count () - 1; i >= 0; --i)
++         if (ctx_at (i) == kind::PDI)
++           {
++             vec.truncate (i);
++             break;
++           }
++       break;
++      case kind::LTR:
++      case kind::RTL:
++       /* These aren't popped by a PDF/PDI.  */
++       break;
++      [[likely]] case kind::NONE:
++       break;
++      default:
++       abort ();
++      }
++  }
++
++  /* Return a descriptive string for K.  */
++  const char *to_str (kind k)
++  {
++    switch (k)
++      {
++      case kind::LRE:
++       return "U+202A (LEFT-TO-RIGHT EMBEDDING)";
++      case kind::RLE:
++       return "U+202B (RIGHT-TO-LEFT EMBEDDING)";
++      case kind::LRO:
++       return "U+202D (LEFT-TO-RIGHT OVERRIDE)";
++      case kind::RLO:
++       return "U+202E (RIGHT-TO-LEFT OVERRIDE)";
++      case kind::LRI:
++       return "U+2066 (LEFT-TO-RIGHT ISOLATE)";
++      case kind::RLI:
++       return "U+2067 (RIGHT-TO-LEFT ISOLATE)";
++      case kind::FSI:
++       return "U+2068 (FIRST STRONG ISOLATE)";
++      case kind::PDF:
++       return "U+202C (POP DIRECTIONAL FORMATTING)";
++      case kind::PDI:
++       return "U+2069 (POP DIRECTIONAL ISOLATE)";
++      case kind::LTR:
++       return "U+200E (LEFT-TO-RIGHT MARK)";
++      case kind::RTL:
++       return "U+200F (RIGHT-TO-LEFT MARK)";
++      default:
++       abort ();
++      }
++  }
++}
++
++/* Parse a sequence of 3 bytes starting with P and return its bidi code.  */
++
++static bidi::kind
++get_bidi_utf8 (const unsigned char *const p)
++{
++  gcc_checking_assert (p[0] == bidi::utf8_start);
++
++  if (p[1] == 0x80)
++    switch (p[2])
++      {
++      case 0xaa:
++       return bidi::kind::LRE;
++      case 0xab:
++       return bidi::kind::RLE;
++      case 0xac:
++       return bidi::kind::PDF;
++      case 0xad:
++       return bidi::kind::LRO;
++      case 0xae:
++       return bidi::kind::RLO;
++      case 0x8e:
++       return bidi::kind::LTR;
++      case 0x8f:
++       return bidi::kind::RTL;
++      default:
++       break;
++      }
++  else if (p[1] == 0x81)
++    switch (p[2])
++      {
++      case 0xa6:
++       return bidi::kind::LRI;
++      case 0xa7:
++       return bidi::kind::RLI;
++      case 0xa8:
++       return bidi::kind::FSI;
++      case 0xa9:
++       return bidi::kind::PDI;
++      default:
++       break;
++      }
++
++  return bidi::kind::NONE;
++}
++
++/* Parse a UCN where P points just past \u or \U and return its bidi code.  */
++
++static bidi::kind
++get_bidi_ucn (const unsigned char *p, bool is_U)
++{
++  /* 6.4.3 Universal Character Names
++      \u hex-quad
++      \U hex-quad hex-quad
++     where \unnnn means \U0000nnnn.  */
++
++  if (is_U)
++    {
++      if (p[0] != '0' || p[1] != '0' || p[2] != '0' || p[3] != '0')
++       return bidi::kind::NONE;
++      /* Skip 4B so we can treat \u and \U the same below.  */
++      p += 4;
++    }
++
++  /* All code points we are looking for start with 20xx.  */
++  if (p[0] != '2' || p[1] != '0')
++    return bidi::kind::NONE;
++  else if (p[2] == '2')
++    switch (p[3])
++      {
++      case 'a':
++      case 'A':
++       return bidi::kind::LRE;
++      case 'b':
++      case 'B':
++       return bidi::kind::RLE;
++      case 'c':
++      case 'C':
++       return bidi::kind::PDF;
++      case 'd':
++      case 'D':
++       return bidi::kind::LRO;
++      case 'e':
++      case 'E':
++       return bidi::kind::RLO;
++      default:
++       break;
++      }
++  else if (p[2] == '6')
++    switch (p[3])
++      {
++      case '6':
++       return bidi::kind::LRI;
++      case '7':
++       return bidi::kind::RLI;
++      case '8':
++       return bidi::kind::FSI;
++      case '9':
++       return bidi::kind::PDI;
++      default:
++       break;
++      }
++  else if (p[2] == '0')
++    switch (p[3])
++      {
++      case 'e':
++      case 'E':
++       return bidi::kind::LTR;
++      case 'f':
++      case 'F':
++       return bidi::kind::RTL;
++      default:
++       break;
++      }
++
++  return bidi::kind::NONE;
++}
++
++/* We're closing a bidi context, that is, we've encountered a newline,
++   are closing a C-style comment, or are at the end of a string literal,
++   character constant, or identifier.  Warn if this context was not
++   properly terminated by a PDI or PDF.  P points to the last character
++   in this context.  */
++
++static void
++maybe_warn_bidi_on_close (cpp_reader *pfile, const uchar *p)
++{
++  if (CPP_OPTION (pfile, cpp_warn_bidirectional) == bidirectional_unpaired
++      && bidi::vec.count () > 0)
++    {
++      const location_t loc
++       = linemap_position_for_column (pfile->line_table,
++                                      CPP_BUF_COLUMN (pfile->buffer, p));
++      cpp_warning_with_line (pfile, CPP_W_BIDIRECTIONAL, loc, 0,
++                            "unpaired UTF-8 bidirectional control character "
++                            "detected");
++    }
++  /* We're done with this context.  */
++  bidi::on_close ();
++}
++
++/* We're at the beginning or in the middle of an identifier/comment/string
++   literal/character constant.  Warn if we've encountered a bidi character.
++   KIND says which bidi character it was; P points to it in the character
++   stream.  UCN_P is true iff this bidi character was written as a UCN.  */
++
++static void
++maybe_warn_bidi_on_char (cpp_reader *pfile, const uchar *p, bidi::kind kind,
++                        bool ucn_p)
++{
++  if (__builtin_expect (kind == bidi::kind::NONE, 1))
++    return;
++
++  const auto warn_bidi = CPP_OPTION (pfile, cpp_warn_bidirectional);
++
++  if (warn_bidi != bidirectional_none)
++    {
++      const location_t loc
++       = linemap_position_for_column (pfile->line_table,
++                                      CPP_BUF_COLUMN (pfile->buffer, p));
++      /* It seems excessive to warn about a PDI/PDF that is closing
++        an opened context because we've already warned about the
++        opening character.  Except warn when we have a UCN x UTF-8
++        mismatch.  */
++      if (kind == bidi::current_ctx ())
++       {
++         if (warn_bidi == bidirectional_unpaired
++             && bidi::current_ctx_ucn_p () != ucn_p)
++           cpp_warning_with_line (pfile, CPP_W_BIDIRECTIONAL, loc, 0,
++                                  "UTF-8 vs UCN mismatch when closing "
++                                  "a context by \"%s\"", bidi::to_str (kind));
++       }
++      else if (warn_bidi == bidirectional_any)
++       {
++         if (kind == bidi::kind::PDF || kind == bidi::kind::PDI)
++           cpp_warning_with_line (pfile, CPP_W_BIDIRECTIONAL, loc, 0,
++                                  "\"%s\" is closing an unopened context",
++                                  bidi::to_str (kind));
++         else
++           cpp_warning_with_line (pfile, CPP_W_BIDIRECTIONAL, loc, 0,
++                                  "found problematic Unicode character \"%s\"",
++                                  bidi::to_str (kind));
++       }
++    }
++  /* We're done with this context.  */
++  bidi::on_char (kind, ucn_p);
++}
++
+ /* Skip a C-style block comment.  We find the end of the comment by
+    seeing if an asterisk is before every '/' we encounter.  Returns
+    nonzero if comment terminated by EOF, zero otherwise.
+@@ -1175,6 +1493,7 @@ _cpp_skip_block_comment (cpp_reader *pfi
+   cpp_buffer *buffer = pfile->buffer;
+   const uchar *cur = buffer->cur;
+   uchar c;
++  const bool warn_bidi_p = pfile->warn_bidi_p ();
+ 
+   cur++;
+   if (*cur == '/')
+@@ -1189,7 +1508,11 @@ _cpp_skip_block_comment (cpp_reader *pfi
+       if (c == '/')
+        {
+          if (cur[-2] == '*')
+-           break;
++           {
++             if (warn_bidi_p)
++               maybe_warn_bidi_on_close (pfile, cur);
++             break;
++           }
+ 
+          /* Warn about potential nested comments, but not if the '/'
+             comes immediately before the true comment delimiter.
+@@ -1208,6 +1531,8 @@ _cpp_skip_block_comment (cpp_reader *pfi
+        {
+          unsigned int cols;
+          buffer->cur = cur - 1;
++         if (warn_bidi_p)
++           maybe_warn_bidi_on_close (pfile, cur);
+          _cpp_process_line_notes (pfile, true);
+          if (buffer->next_line >= buffer->rlimit)
+            return true;
+@@ -1218,6 +1543,13 @@ _cpp_skip_block_comment (cpp_reader *pfi
+ 
+          cur = buffer->cur;
+        }
++      /* If this is a beginning of a UTF-8 encoding, it might be
++        a bidirectional control character.  */
++      else if (__builtin_expect (c == bidi::utf8_start, 0) && warn_bidi_p)
++       {
++         bidi::kind kind = get_bidi_utf8 (cur - 1);
++         maybe_warn_bidi_on_char (pfile, cur, kind, /*ucn_p=*/false);
++       }
+     }
+ 
+   buffer->cur = cur;
+@@ -1233,9 +1565,31 @@ skip_line_comment (cpp_reader *pfile)
+ {
+   cpp_buffer *buffer = pfile->buffer;
+   location_t orig_line = pfile->line_table->highest_line;
++  const bool warn_bidi_p = pfile->warn_bidi_p ();
+ 
+-  while (*buffer->cur != '\n')
+-    buffer->cur++;
++  if (!warn_bidi_p)
++    while (*buffer->cur != '\n')
++      buffer->cur++;
++  else
++    {
++      while (*buffer->cur != '\n'
++            && *buffer->cur != bidi::utf8_start)
++       buffer->cur++;
++      if (__builtin_expect (*buffer->cur == bidi::utf8_start, 0))
++       {
++         while (*buffer->cur != '\n')
++           {
++             if (__builtin_expect (*buffer->cur == bidi::utf8_start, 0))
++               {
++                 bidi::kind kind = get_bidi_utf8 (buffer->cur);
++                 maybe_warn_bidi_on_char (pfile, buffer->cur, kind,
++                                          /*ucn_p=*/false);
++               }
++             buffer->cur++;
++           }
++         maybe_warn_bidi_on_close (pfile, buffer->cur);
++       }
++    }
+ 
+   _cpp_process_line_notes (pfile, true);
+   return orig_line != pfile->line_table->highest_line;
+@@ -1343,11 +1697,13 @@ static const cppchar_t utf8_signifier =
+ 
+ /* Returns TRUE if the sequence starting at buffer->cur is valid in
+    an identifier.  FIRST is TRUE if this starts an identifier.  */
++
+ static bool
+ forms_identifier_p (cpp_reader *pfile, int first,
+                    struct normalize_state *state)
+ {
+   cpp_buffer *buffer = pfile->buffer;
++  const bool warn_bidi_p = pfile->warn_bidi_p ();
+ 
+   if (*buffer->cur == '$')
+     {
+@@ -1370,6 +1726,13 @@ forms_identifier_p (cpp_reader *pfile, i
+       cppchar_t s;
+       if (*buffer->cur >= utf8_signifier)
+        {
++         if (__builtin_expect (*buffer->cur == bidi::utf8_start, 0)
++             && warn_bidi_p)
++           {
++             bidi::kind kind = get_bidi_utf8 (buffer->cur);
++             maybe_warn_bidi_on_char (pfile, buffer->cur, kind,
++                                      /*ucn_p=*/false);
++           }
+          if (_cpp_valid_utf8 (pfile, &buffer->cur, buffer->rlimit, 1 + !first,
+                               state, &s))
+            return true;
+@@ -1378,6 +1741,13 @@ forms_identifier_p (cpp_reader *pfile, i
+               && (buffer->cur[1] == 'u' || buffer->cur[1] == 'U'))
+        {
+          buffer->cur += 2;
++         if (warn_bidi_p)
++           {
++             bidi::kind kind = get_bidi_ucn (buffer->cur,
++                                             buffer->cur[-1] == 'U');
++             maybe_warn_bidi_on_char (pfile, buffer->cur, kind,
++                                      /*ucn_p=*/true);
++           }
+          if (_cpp_valid_ucn (pfile, &buffer->cur, buffer->rlimit, 1 + !first,
+                              state, &s, NULL, NULL))
+            return true;
+@@ -1486,6 +1856,7 @@ lex_identifier (cpp_reader *pfile, const
+   const uchar *cur;
+   unsigned int len;
+   unsigned int hash = HT_HASHSTEP (0, *base);
++  const bool warn_bidi_p = pfile->warn_bidi_p ();
+ 
+   cur = pfile->buffer->cur;
+   if (! starts_ucn)
+@@ -1509,6 +1880,8 @@ lex_identifier (cpp_reader *pfile, const
+            pfile->buffer->cur++;
+          }
+       } while (forms_identifier_p (pfile, false, nst));
++      if (warn_bidi_p)
++       maybe_warn_bidi_on_close (pfile, pfile->buffer->cur);
+       result = _cpp_interpret_identifier (pfile, base,
+                                          pfile->buffer->cur - base);
+       *spelling = cpp_lookup (pfile, base, pfile->buffer->cur - base);
+@@ -1697,6 +2070,7 @@ lex_raw_string (cpp_reader *pfile, cpp_t
+ {
+   uchar raw_prefix[17];
+   uchar temp_buffer[18];
++  const bool warn_bidi_p = pfile->warn_bidi_p ();
+   const uchar *orig_base;
+   unsigned int raw_prefix_len = 0, raw_suffix_len = 0;
+   enum raw_str_phase { RAW_STR_PREFIX, RAW_STR, RAW_STR_SUFFIX };
+@@ -1946,8 +2320,15 @@ lex_raw_string (cpp_reader *pfile, cpp_t
+          cur = base = pfile->buffer->cur;
+          note = &pfile->buffer->notes[pfile->buffer->cur_note];
+        }
++      else if (__builtin_expect ((unsigned char) c == bidi::utf8_start, 0)
++              && warn_bidi_p)
++       maybe_warn_bidi_on_char (pfile, pos - 1, get_bidi_utf8 (pos - 1),
++                                /*ucn_p=*/false);
+     }
+ 
++  if (warn_bidi_p)
++    maybe_warn_bidi_on_close (pfile, pos);
++
+   if (CPP_OPTION (pfile, user_literals))
+     {
+       /* If a string format macro, say from inttypes.h, is placed touching
+@@ -2042,15 +2423,27 @@ lex_string (cpp_reader *pfile, cpp_token
+   else
+     terminator = '>', type = CPP_HEADER_NAME;
+ 
++  const bool warn_bidi_p = pfile->warn_bidi_p ();
+   for (;;)
+     {
+       cppchar_t c = *cur++;
+ 
+       /* In #include-style directives, terminators are not escapable.  */
+       if (c == '\\' && !pfile->state.angled_headers && *cur != '\n')
+-       cur++;
++       {
++         if ((cur[0] == 'u' || cur[0] == 'U') && warn_bidi_p)
++           {
++             bidi::kind kind = get_bidi_ucn (cur + 1, cur[0] == 'U');
++             maybe_warn_bidi_on_char (pfile, cur, kind, /*ucn_p=*/true);
++           }
++         cur++;
++       }
+       else if (c == terminator)
+-       break;
++       {
++         if (warn_bidi_p)
++           maybe_warn_bidi_on_close (pfile, cur - 1);
++         break;
++       }
+       else if (c == '\n')
+        {
+          cur--;
+@@ -2067,6 +2460,11 @@ lex_string (cpp_reader *pfile, cpp_token
+        }
+       else if (c == '\0')
+        saw_NUL = true;
++      else if (__builtin_expect (c == bidi::utf8_start, 0) && warn_bidi_p)
++       {
++         bidi::kind kind = get_bidi_utf8 (cur - 1);
++         maybe_warn_bidi_on_char (pfile, cur - 1, kind, /*ucn_p=*/false);
++       }
+     }
+ 
+   if (saw_NUL && !pfile->state.skipping)
diff --git a/meta/recipes-devtools/gcc/gcc/0004-CVE-2021-42574.patch b/meta/recipes-devtools/gcc/gcc/0004-CVE-2021-42574.patch
new file mode 100644
index 0000000000..877b8a6452
--- /dev/null
+++ b/meta/recipes-devtools/gcc/gcc/0004-CVE-2021-42574.patch
@@ -0,0 +1,138 @@
+From 1a7f2c0774129750fdf73e9f1b78f0ce983c9ab3 Mon Sep 17 00:00:00 2001
+From: David Malcolm <dmalcolm@redhat.com>
+Date: Tue, 2 Nov 2021 09:54:32 -0400
+Subject: [PATCH] libcpp: escape non-ASCII source bytes in -Wbidi-chars=
+ [PR103026]
+MIME-Version: 1.0
+Content-Type: text/plain; charset=utf8
+Content-Transfer-Encoding: 8bit
+
+This flags rich_locations associated with -Wbidi-chars= so that
+non-ASCII bytes will be escaped when printing the source lines
+(using the diagnostics support I added in
+r12-4825-gbd5e882cf6e0def3dd1bc106075d59a303fe0d1e).
+
+In particular, this ensures that the printed source lines will
+be pure ASCII, and thus the visual ordering of the characters
+will be the same as the logical ordering.
+
+Before:
+
+  Wbidi-chars-1.c: In function âmainâ:
+  Wbidi-chars-1.c:6:43: warning: unpaired UTF-8 bidirectional control character detected [-Wbidi-chars=]
+      6 |     /*â® } â¦if (isAdmin)⩠⦠begin admins only */
+        |                                           ^
+  Wbidi-chars-1.c:9:28: warning: unpaired UTF-8 bidirectional control character detected [-Wbidi-chars=]
+      9 |     /* end admins only â® { â¦*/
+        |                            ^
+
+  Wbidi-chars-11.c:6:15: warning: UTF-8 vs UCN mismatch when closing a context by "U+202C (POP DIRECTIONAL FORMATTING)" [-Wbidi-chars=]
+      6 | int LRE_âª_PDF_\u202c;
+        |               ^
+  Wbidi-chars-11.c:8:19: warning: UTF-8 vs UCN mismatch when closing a context by "U+202C (POP DIRECTIONAL FORMATTING)" [-Wbidi-chars=]
+      8 | int LRE_\u202a_PDF_â¬_;
+        |                   ^
+  Wbidi-chars-11.c:10:28: warning: UTF-8 vs UCN mismatch when closing a context by "U+202C (POP DIRECTIONAL FORMATTING)" [-Wbidi-chars=]
+     10 | const char *s1 = "LRE_âª_PDF_\u202c";
+        |                            ^
+  Wbidi-chars-11.c:12:33: warning: UTF-8 vs UCN mismatch when closing a context by "U+202C (POP DIRECTIONAL FORMATTING)" [-Wbidi-chars=]
+     12 | const char *s2 = "LRE_\u202a_PDF_â¬";
+        |                                 ^
+
+After:
+
+  Wbidi-chars-1.c: In function âmainâ:
+  Wbidi-chars-1.c:6:43: warning: unpaired UTF-8 bidirectional control character detected [-Wbidi-chars=]
+      6 |     /*<U+202E> } <U+2066>if (isAdmin)<U+2069> <U+2066> begin admins only */
+        |                                                                           ^
+  Wbidi-chars-1.c:9:28: warning: unpaired UTF-8 bidirectional control character detected [-Wbidi-chars=]
+      9 |     /* end admins only <U+202E> { <U+2066>*/
+        |                                            ^
+
+  Wbidi-chars-11.c:6:15: warning: UTF-8 vs UCN mismatch when closing a context by "U+202C (POP DIRECTIONAL FORMATTING)" [-Wbidi-chars=]
+      6 | int LRE_<U+202A>_PDF_\u202c;
+        |                       ^
+  Wbidi-chars-11.c:8:19: warning: UTF-8 vs UCN mismatch when closing a context by "U+202C (POP DIRECTIONAL FORMATTING)" [-Wbidi-chars=]
+      8 | int LRE_\u202a_PDF_<U+202C>_;
+        |                   ^
+  Wbidi-chars-11.c:10:28: warning: UTF-8 vs UCN mismatch when closing a context by "U+202C (POP DIRECTIONAL FORMATTING)" [-Wbidi-chars=]
+     10 | const char *s1 = "LRE_<U+202A>_PDF_\u202c";
+        |                                    ^
+  Wbidi-chars-11.c:12:33: warning: UTF-8 vs UCN mismatch when closing a context by "U+202C (POP DIRECTIONAL FORMATTING)" [-Wbidi-chars=]
+     12 | const char *s2 = "LRE_\u202a_PDF_<U+202C>";
+        |                                 ^
+
+libcpp/ChangeLog:
+        PR preprocessor/103026
+        * lex.c (maybe_warn_bidi_on_close): Use a rich_location
+        and call set_escape_on_output (true) on it.
+        (maybe_warn_bidi_on_char): Likewise.
+
+Signed-off-by: David Malcolm <dmalcolm@redhat.com>
+
+CVE: CVE-2021-42574
+Upstream-Status: Backport [https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=1a7f2c0774129750fdf73e9f1b78f0ce983c9ab3]
+Signed-off-by: Pgowda <pgowda.cve@gmail.com>
+
+---
+ libcpp/lex.c | 29 +++++++++++++++++------------
+ 1 file changed, 17 insertions(+), 12 deletions(-)
+
+diff --git a/libcpp/lex.c b/libcpp/lex.c
+--- a/libcpp/lex.c      2021-12-14 20:44:11.647815287 -0800
++++ b/libcpp/lex.c      2021-12-14 20:43:38.008383220 -0800
+@@ -1427,9 +1427,11 @@ maybe_warn_bidi_on_close (cpp_reader *pf
+       const location_t loc
+        = linemap_position_for_column (pfile->line_table,
+                                       CPP_BUF_COLUMN (pfile->buffer, p));
+-      cpp_warning_with_line (pfile, CPP_W_BIDIRECTIONAL, loc, 0,
+-                            "unpaired UTF-8 bidirectional control character "
+-                            "detected");
++      rich_location rich_loc (pfile->line_table, loc);
++      rich_loc.set_escape_on_output (true);
++      cpp_warning_at (pfile, CPP_W_BIDIRECTIONAL, &rich_loc,
++                     "unpaired UTF-8 bidirectional control character "
++                     "detected");
+     }
+   /* We're done with this context.  */
+   bidi::on_close ();
+@@ -1454,6 +1456,9 @@ maybe_warn_bidi_on_char (cpp_reader *pfi
+       const location_t loc
+        = linemap_position_for_column (pfile->line_table,
+                                       CPP_BUF_COLUMN (pfile->buffer, p));
++      rich_location rich_loc (pfile->line_table, loc);
++      rich_loc.set_escape_on_output (true);
++
+       /* It seems excessive to warn about a PDI/PDF that is closing
+         an opened context because we've already warned about the
+         opening character.  Except warn when we have a UCN x UTF-8
+@@ -1462,20 +1467,20 @@ maybe_warn_bidi_on_char (cpp_reader *pfi
+        {
+          if (warn_bidi == bidirectional_unpaired
+              && bidi::current_ctx_ucn_p () != ucn_p)
+-           cpp_warning_with_line (pfile, CPP_W_BIDIRECTIONAL, loc, 0,
+-                                  "UTF-8 vs UCN mismatch when closing "
+-                                  "a context by \"%s\"", bidi::to_str (kind));
++           cpp_warning_at (pfile, CPP_W_BIDIRECTIONAL, &rich_loc,
++                           "UTF-8 vs UCN mismatch when closing "
++                           "a context by \"%s\"", bidi::to_str (kind));
+        }
+       else if (warn_bidi == bidirectional_any)
+        {
+          if (kind == bidi::kind::PDF || kind == bidi::kind::PDI)
+-           cpp_warning_with_line (pfile, CPP_W_BIDIRECTIONAL, loc, 0,
+-                                  "\"%s\" is closing an unopened context",
+-                                  bidi::to_str (kind));
++           cpp_warning_at (pfile, CPP_W_BIDIRECTIONAL, &rich_loc,
++                           "\"%s\" is closing an unopened context",
++                           bidi::to_str (kind));
+          else
+-           cpp_warning_with_line (pfile, CPP_W_BIDIRECTIONAL, loc, 0,
+-                                  "found problematic Unicode character \"%s\"",
+-                                  bidi::to_str (kind));
++           cpp_warning_at (pfile, CPP_W_BIDIRECTIONAL, &rich_loc,
++                           "found problematic Unicode character \"%s\"",
++                           bidi::to_str (kind));
+        }
+     }
+   /* We're done with this context.  */
diff --git a/meta/recipes-devtools/gcc/gcc/0005-CVE-2021-42574.patch b/meta/recipes-devtools/gcc/gcc/0005-CVE-2021-42574.patch
new file mode 100644
index 0000000000..6e983a67b6
--- /dev/null
+++ b/meta/recipes-devtools/gcc/gcc/0005-CVE-2021-42574.patch
@@ -0,0 +1,575 @@
+From bef32d4a28595e933f24fef378cf052a30b674a7 Mon Sep 17 00:00:00 2001
+From: David Malcolm <dmalcolm@redhat.com>
+Date: Tue, 2 Nov 2021 15:45:22 -0400
+Subject: [PATCH] libcpp: capture and underline ranges in -Wbidi-chars=
+ [PR103026]
+MIME-Version: 1.0
+Content-Type: text/plain; charset=utf8
+Content-Transfer-Encoding: 8bit
+
+This patch converts the bidi::vec to use a struct so that we can
+capture location_t values for the bidirectional control characters.
+
+Before:
+
+  Wbidi-chars-1.c: In function âmainâ:
+  Wbidi-chars-1.c:6:43: warning: unpaired UTF-8 bidirectional control character detected [-Wbidi-chars=]
+      6 |     /*<U+202E> } <U+2066>if (isAdmin)<U+2069> <U+2066> begin admins only */
+        |                                                                           ^
+  Wbidi-chars-1.c:9:28: warning: unpaired UTF-8 bidirectional control character detected [-Wbidi-chars=]
+      9 |     /* end admins only <U+202E> { <U+2066>*/
+        |                                            ^
+
+After:
+
+  Wbidi-chars-1.c: In function âmainâ:
+  Wbidi-chars-1.c:6:43: warning: unpaired UTF-8 bidirectional control characters detected [-Wbidi-chars=]
+      6 |     /*<U+202E> } <U+2066>if (isAdmin)<U+2069> <U+2066> begin admins only */
+        |       ~~~~~~~~                                ~~~~~~~~                    ^
+        |       |                                       |                           |
+        |       |                                       |                           end of bidirectional context
+        |       U+202E (RIGHT-TO-LEFT OVERRIDE)         U+2066 (LEFT-TO-RIGHT ISOLATE)
+  Wbidi-chars-1.c:9:28: warning: unpaired UTF-8 bidirectional control characters detected [-Wbidi-chars=]
+      9 |     /* end admins only <U+202E> { <U+2066>*/
+        |                        ~~~~~~~~   ~~~~~~~~ ^
+        |                        |          |        |
+        |                        |          |        end of bidirectional context
+        |                        |          U+2066 (LEFT-TO-RIGHT ISOLATE)
+        |                        U+202E (RIGHT-TO-LEFT OVERRIDE)
+
+Signed-off-by: David Malcolm <dmalcolm@redhat.com>
+
+gcc/testsuite/ChangeLog:
+        PR preprocessor/103026
+        * c-c++-common/Wbidi-chars-ranges.c: New test.
+
+libcpp/ChangeLog:
+        PR preprocessor/103026
+        * lex.c (struct bidi::context): New.
+        (bidi::vec): Convert to a vec of context rather than unsigned
+        char.
+        (bidi::ctx_at): Rename to...
+        (bidi::pop_kind_at): ...this and reimplement for above change.
+        (bidi::current_ctx): Update for change to vec.
+        (bidi::current_ctx_ucn_p): Likewise.
+        (bidi::current_ctx_loc): New.
+        (bidi::on_char): Update for usage of context struct.  Add "loc"
+        param and pass it when pushing contexts.
+        (get_location_for_byte_range_in_cur_line): New.
+        (get_bidi_utf8): Rename to...
+        (get_bidi_utf8_1): ...this, reintroducing...
+        (get_bidi_utf8): ...as a wrapper, setting *OUT when the result is
+        not NONE.
+        (get_bidi_ucn): Rename to...
+        (get_bidi_ucn_1): ...this, reintroducing...
+        (get_bidi_ucn): ...as a wrapper, setting *OUT when the result is
+        not NONE.
+        (class unpaired_bidi_rich_location): New.
+        (maybe_warn_bidi_on_close): Use unpaired_bidi_rich_location when
+        reporting on unpaired bidi chars.  Split into singular vs plural
+        spellings.
+        (maybe_warn_bidi_on_char): Pass in a location_t rather than a
+        const uchar * and use it when emitting warnings, and when calling
+        bidi::on_char.
+        (_cpp_skip_block_comment): Capture location when kind is not NONE
+        and pass it to maybe_warn_bidi_on_char.
+        (skip_line_comment): Likewise.
+        (forms_identifier_p): Likewise.
+        (lex_raw_string): Likewise.
+        (lex_string): Likewise.
+
+Signed-off-by: David Malcolm <dmalcolm@redhat.com>
+
+CVE: CVE-2021-42574
+Upstream-Status: Backport [https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=bef32d4a28595e933f24fef378cf052a30b674a7]
+Signed-off-by: Pgowda <pgowda.cve@gmail.com>
+
+---
+ .../c-c++-common/Wbidi-chars-ranges.c         |  54 ++++
+ libcpp/lex.c                                  | 251 ++++++++++++++----
+ 2 files changed, 257 insertions(+), 48 deletions(-)
+ create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-ranges.c
+
+diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-ranges.c b/gcc/testsuite/c-c++-common/Wbidi-chars-ranges.c
+--- a/gcc/testsuite/c-c++-common/Wbidi-chars-ranges.c   1969-12-31 16:00:00.000000000 -0800
++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-ranges.c   2021-12-25 01:39:55.116281847 -0800
+@@ -0,0 +1,54 @@
++/* PR preprocessor/103026 */
++/* { dg-do compile } */
++/* { dg-options "-Wbidi-chars=unpaired -fdiagnostics-show-caret" } */
++/* Verify that we escape and underline pertinent bidirectional
++   control characters when quoting the source.  */
++
++int test_unpaired_bidi () {
++    int isAdmin = 0;
++    /*‮ } ⁦if (isAdmin)⁩ ⁦ begin admins only */
++/* { dg-warning "bidirectional" "" { target *-*-* } .-1 } */
++#if 0
++   { dg-begin-multiline-output "" }
++     /*<U+202E> } <U+2066>if (isAdmin)<U+2069> <U+2066> begin admins only */
++       ~~~~~~~~                                ~~~~~~~~                    ^
++       |                                       |                           |
++       |                                       |                           end of bidirectional context
++       U+202E (RIGHT-TO-LEFT OVERRIDE)         U+2066 (LEFT-TO-RIGHT ISOLATE)
++   { dg-end-multiline-output "" }
++#endif
++
++        __builtin_printf("You are an admin.\n");
++    /* end admins only ‮ { ⁦*/
++/* { dg-warning "bidirectional" "" { target *-*-* } .-1 } */
++#if 0
++   { dg-begin-multiline-output "" }
++     /* end admins only <U+202E> { <U+2066>*/
++                        ~~~~~~~~   ~~~~~~~~ ^
++                        |          |        |
++                        |          |        end of bidirectional context
++                        |          U+2066 (LEFT-TO-RIGHT ISOLATE)
++                        U+202E (RIGHT-TO-LEFT OVERRIDE)
++   { dg-end-multiline-output "" }
++#endif
++
++    return 0;
++}
++
++int LRE_‪_PDF_\u202c;
++/* { dg-warning "mismatch" "" { target *-*-* } .-1 } */
++#if 0
++   { dg-begin-multiline-output "" }
++ int LRE_<U+202A>_PDF_\u202c;
++         ~~~~~~~~     ^~~~~~
++   { dg-end-multiline-output "" }
++#endif
++
++const char *s1 = "LRE_‪_PDF_\u202c";
++/* { dg-warning "mismatch" "" { target *-*-* } .-1 } */
++#if 0
++   { dg-begin-multiline-output "" }
++ const char *s1 = "LRE_<U+202A>_PDF_\u202c";
++                       ~~~~~~~~     ^~~~~~
++   { dg-end-multiline-output "" }
++#endif
+diff --git a/libcpp/lex.c b/libcpp/lex.c
+--- a/libcpp/lex.c      2021-12-25 01:41:16.522868808 -0800
++++ b/libcpp/lex.c      2021-12-25 06:28:58.530680302 -0800
+@@ -1172,11 +1172,34 @@ namespace bidi {
+   /* All the UTF-8 encodings of bidi characters start with E2.  */
+   constexpr uchar utf8_start = 0xe2;
+ 
++  struct context
++  {
++    context () {}
++    context (location_t loc, kind k, bool pdf, bool ucn)
++    : m_loc (loc), m_kind (k), m_pdf (pdf), m_ucn (ucn)
++    {
++    }
++
++    kind get_pop_kind () const
++    {
++      return m_pdf ? kind::PDF : kind::PDI;
++    }
++    bool ucn_p () const
++    {
++      return m_ucn;
++    }
++
++    location_t m_loc;
++    kind m_kind;
++    unsigned m_pdf : 1;
++    unsigned m_ucn : 1;
++  };
++
+   /* A vector holding currently open bidi contexts.  We use a char for
+      each context, its LSB is 1 if it represents a PDF context, 0 if it
+      represents a PDI context.  The next bit is 1 if this context was open
+      by a bidi character written as a UCN, and 0 when it was UTF-8.  */
+-  semi_embedded_vec <unsigned char, 16> vec;
++  semi_embedded_vec <context, 16> vec;
+ 
+   /* Close the whole comment/identifier/string literal/character constant
+      context.  */
+@@ -1193,19 +1216,19 @@ namespace bidi {
+     vec.truncate (len - 1);
+   }
+ 
+-  /* Return the context of the Ith element.  */
+-  kind ctx_at (unsigned int i)
++  /* Return the pop kind of the context of the Ith element.  */
++  kind pop_kind_at (unsigned int i)
+   {
+-    return (vec[i] & 1) ? kind::PDF : kind::PDI;
++    return vec[i].get_pop_kind ();
+   }
+ 
+-  /* Return which context is currently opened.  */
++  /* Return the pop kind of the context that is currently opened.  */
+   kind current_ctx ()
+   {
+     unsigned int len = vec.count ();
+     if (len == 0)
+       return kind::NONE;
+-    return ctx_at (len - 1);
++    return vec[len - 1].get_pop_kind ();
+   }
+ 
+   /* Return true if the current context comes from a UCN origin, that is,
+@@ -1214,11 +1237,19 @@ namespace bidi {
+   {
+     unsigned int len = vec.count ();
+     gcc_checking_assert (len > 0);
+-    return (vec[len - 1] >> 1) & 1;
++    return vec[len - 1].m_ucn;
+   }
+ 
+-  /* We've read a bidi char, update the current vector as necessary.  */
+-  void on_char (kind k, bool ucn_p)
++  location_t current_ctx_loc ()
++  {
++    unsigned int len = vec.count ();
++    gcc_checking_assert (len > 0);
++    return vec[len - 1].m_loc;
++  }
++
++  /* We've read a bidi char, update the current vector as necessary.
++     LOC is only valid when K is not kind::NONE.  */
++  void on_char (kind k, bool ucn_p, location_t loc)
+   {
+     switch (k)
+       {
+@@ -1226,12 +1257,12 @@ namespace bidi {
+       case kind::RLE:
+       case kind::LRO:
+       case kind::RLO:
+-       vec.push (ucn_p ? 3u : 1u);
++       vec.push (context (loc, k, true, ucn_p));
+        break;
+       case kind::LRI:
+       case kind::RLI:
+       case kind::FSI:
+-       vec.push (ucn_p ? 2u : 0u);
++       vec.push (context (loc, k, false, ucn_p));
+        break;
+       /* PDF terminates the scope of the last LRE, RLE, LRO, or RLO
+         whose scope has not yet been terminated.  */
+@@ -1245,7 +1276,7 @@ namespace bidi {
+         yet been terminated.  */
+       case kind::PDI:
+        for (int i = vec.count () - 1; i >= 0; --i)
+-         if (ctx_at (i) == kind::PDI)
++         if (pop_kind_at (i) == kind::PDI)
+            {
+              vec.truncate (i);
+              break;
+@@ -1295,10 +1326,47 @@ namespace bidi {
+   }
+ }
+ 
++/* Get location_t for the range of bytes [START, START + NUM_BYTES)
++   within the current line in FILE, with the caret at START.  */
++
++static location_t
++get_location_for_byte_range_in_cur_line (cpp_reader *pfile,
++                                        const unsigned char *const start,
++                                        size_t num_bytes)
++{
++  gcc_checking_assert (num_bytes > 0);
++
++  /* CPP_BUF_COLUMN and linemap_position_for_column both refer
++     to offsets in bytes, but CPP_BUF_COLUMN is 0-based,
++     whereas linemap_position_for_column is 1-based.  */
++
++  /* Get 0-based offsets within the line.  */
++  size_t start_offset = CPP_BUF_COLUMN (pfile->buffer, start);
++  size_t end_offset = start_offset + num_bytes - 1;
++
++  /* Now convert to location_t, where "columns" are 1-based byte offsets.  */
++  location_t start_loc = linemap_position_for_column (pfile->line_table,
++                                                     start_offset + 1);
++  location_t end_loc = linemap_position_for_column (pfile->line_table,
++                                                    end_offset + 1);
++
++  if (start_loc == end_loc)
++    return start_loc;
++
++  source_range src_range;
++  src_range.m_start = start_loc;
++  src_range.m_finish = end_loc;
++  location_t combined_loc = COMBINE_LOCATION_DATA (pfile->line_table,
++                                                  start_loc,
++                                                  src_range,
++                                                  NULL);
++  return combined_loc;
++}
++
+ /* Parse a sequence of 3 bytes starting with P and return its bidi code.  */
+ 
+ static bidi::kind
+-get_bidi_utf8 (const unsigned char *const p)
++get_bidi_utf8_1 (const unsigned char *const p)
+ {
+   gcc_checking_assert (p[0] == bidi::utf8_start);
+ 
+@@ -1340,10 +1408,25 @@ get_bidi_utf8 (const unsigned char *cons
+   return bidi::kind::NONE;
+ }
+ 
++/* Parse a sequence of 3 bytes starting with P and return its bidi code.
++   If the kind is not NONE, write the location to *OUT.*/
++
++static bidi::kind
++get_bidi_utf8 (cpp_reader *pfile, const unsigned char *const p, location_t *out)
++{
++  bidi::kind result = get_bidi_utf8_1 (p);
++  if (result != bidi::kind::NONE)
++    {
++      /* We have a sequence of 3 bytes starting at P.  */
++      *out = get_location_for_byte_range_in_cur_line (pfile, p, 3);
++    }
++  return result;
++}
++
+ /* Parse a UCN where P points just past \u or \U and return its bidi code.  */
+ 
+ static bidi::kind
+-get_bidi_ucn (const unsigned char *p, bool is_U)
++get_bidi_ucn_1 (const unsigned char *p, bool is_U)
+ {
+   /* 6.4.3 Universal Character Names
+       \u hex-quad
+@@ -1412,6 +1495,62 @@ get_bidi_ucn (const unsigned char *p, bo
+   return bidi::kind::NONE;
+ }
+ 
++/* Parse a UCN where P points just past \u or \U and return its bidi code.
++   If the kind is not NONE, write the location to *OUT.*/
++
++static bidi::kind
++get_bidi_ucn (cpp_reader *pfile,  const unsigned char *p, bool is_U,
++             location_t *out)
++{
++  bidi::kind result = get_bidi_ucn_1 (p, is_U);
++  if (result != bidi::kind::NONE)
++    {
++      const unsigned char *start = p - 2;
++      size_t num_bytes = 2 + (is_U ? 8 : 4);
++      *out = get_location_for_byte_range_in_cur_line (pfile, start, num_bytes);
++    }
++  return result;
++}
++
++/* Subclass of rich_location for reporting on unpaired UTF-8
++   bidirectional control character(s).
++   Escape the source lines on output, and show all unclosed
++   bidi context, labelling everything.  */
++
++class unpaired_bidi_rich_location : public rich_location
++{
++ public:
++  class custom_range_label : public range_label
++  {
++   public:
++     label_text get_text (unsigned range_idx) const FINAL OVERRIDE
++     {
++       /* range 0 is the primary location; each subsequent range i + 1
++         is for bidi::vec[i].  */
++       if (range_idx > 0)
++        {
++          const bidi::context &ctxt (bidi::vec[range_idx - 1]);
++          return label_text::borrow (bidi::to_str (ctxt.m_kind));
++        }
++       else
++        return label_text::borrow (_("end of bidirectional context"));
++     }
++  };
++
++  unpaired_bidi_rich_location (cpp_reader *pfile, location_t loc)
++  : rich_location (pfile->line_table, loc, &m_custom_label)
++  {
++    set_escape_on_output (true);
++    for (unsigned i = 0; i < bidi::vec.count (); i++)
++      add_range (bidi::vec[i].m_loc,
++                SHOW_RANGE_WITHOUT_CARET,
++                &m_custom_label);
++  }
++
++ private:
++   custom_range_label m_custom_label;
++};
++
+ /* We're closing a bidi context, that is, we've encountered a newline,
+    are closing a C-style comment, or are at the end of a string literal,
+    character constant, or identifier.  Warn if this context was not
+@@ -1427,11 +1566,17 @@ maybe_warn_bidi_on_close (cpp_reader *pf
+       const location_t loc
+        = linemap_position_for_column (pfile->line_table,
+                                       CPP_BUF_COLUMN (pfile->buffer, p));
+-      rich_location rich_loc (pfile->line_table, loc);
+-      rich_loc.set_escape_on_output (true);
+-      cpp_warning_at (pfile, CPP_W_BIDIRECTIONAL, &rich_loc,
+-                     "unpaired UTF-8 bidirectional control character "
+-                     "detected");
++      unpaired_bidi_rich_location rich_loc (pfile, loc);
++      /* cpp_callbacks doesn't yet have a way to handle singular vs plural
++        forms of a diagnostic, so fake it for now.  */
++      if (bidi::vec.count () > 1)
++       cpp_warning_at (pfile, CPP_W_BIDIRECTIONAL, &rich_loc,
++                       "unpaired UTF-8 bidirectional control characters "
++                       "detected");
++      else
++       cpp_warning_at (pfile, CPP_W_BIDIRECTIONAL, &rich_loc,
++                       "unpaired UTF-8 bidirectional control character "
++                       "detected");
+     }
+   /* We're done with this context.  */
+   bidi::on_close ();
+@@ -1439,12 +1584,13 @@ maybe_warn_bidi_on_close (cpp_reader *pf
+ 
+ /* We're at the beginning or in the middle of an identifier/comment/string
+    literal/character constant.  Warn if we've encountered a bidi character.
+-   KIND says which bidi character it was; P points to it in the character
+-   stream.  UCN_P is true iff this bidi character was written as a UCN.  */
++   KIND says which bidi control character it was; UCN_P is true iff this bidi
++   control character was written as a UCN.  LOC is the location of the
++   character, but is only valid if KIND != bidi::kind::NONE.  */
+ 
+ static void
+-maybe_warn_bidi_on_char (cpp_reader *pfile, const uchar *p, bidi::kind kind,
+-                        bool ucn_p)
++maybe_warn_bidi_on_char (cpp_reader *pfile, bidi::kind kind,
++                        bool ucn_p, location_t loc)
+ {
+   if (__builtin_expect (kind == bidi::kind::NONE, 1))
+     return;
+@@ -1453,9 +1599,6 @@ maybe_warn_bidi_on_char (cpp_reader *pfi
+ 
+   if (warn_bidi != bidirectional_none)
+     {
+-      const location_t loc
+-       = linemap_position_for_column (pfile->line_table,
+-                                      CPP_BUF_COLUMN (pfile->buffer, p));
+       rich_location rich_loc (pfile->line_table, loc);
+       rich_loc.set_escape_on_output (true);
+ 
+@@ -1467,9 +1610,12 @@ maybe_warn_bidi_on_char (cpp_reader *pfi
+        {
+          if (warn_bidi == bidirectional_unpaired
+              && bidi::current_ctx_ucn_p () != ucn_p)
+-           cpp_warning_at (pfile, CPP_W_BIDIRECTIONAL, &rich_loc,
+-                           "UTF-8 vs UCN mismatch when closing "
+-                           "a context by \"%s\"", bidi::to_str (kind));
++           {
++             rich_loc.add_range (bidi::current_ctx_loc ());
++             cpp_warning_at (pfile, CPP_W_BIDIRECTIONAL, &rich_loc,
++                             "UTF-8 vs UCN mismatch when closing "
++                             "a context by \"%s\"", bidi::to_str (kind));
++           }
+        }
+       else if (warn_bidi == bidirectional_any)
+        {
+@@ -1484,7 +1630,7 @@ maybe_warn_bidi_on_char (cpp_reader *pfi
+        }
+     }
+   /* We're done with this context.  */
+-  bidi::on_char (kind, ucn_p);
++  bidi::on_char (kind, ucn_p, loc);
+ }
+ 
+ /* Skip a C-style block comment.  We find the end of the comment by
+@@ -1552,8 +1698,9 @@ _cpp_skip_block_comment (cpp_reader *pfi
+         a bidirectional control character.  */
+       else if (__builtin_expect (c == bidi::utf8_start, 0) && warn_bidi_p)
+        {
+-         bidi::kind kind = get_bidi_utf8 (cur - 1);
+-         maybe_warn_bidi_on_char (pfile, cur, kind, /*ucn_p=*/false);
++         location_t loc;
++         bidi::kind kind = get_bidi_utf8 (pfile, cur - 1, &loc);
++         maybe_warn_bidi_on_char (pfile, kind, /*ucn_p=*/false, loc);
+        }
+     }
+ 
+@@ -1586,9 +1733,9 @@ skip_line_comment (cpp_reader *pfile)
+            {
+              if (__builtin_expect (*buffer->cur == bidi::utf8_start, 0))
+                {
+-                 bidi::kind kind = get_bidi_utf8 (buffer->cur);
+-                 maybe_warn_bidi_on_char (pfile, buffer->cur, kind,
+-                                          /*ucn_p=*/false);
++                 location_t loc;
++                 bidi::kind kind = get_bidi_utf8 (pfile, buffer->cur, &loc);
++                 maybe_warn_bidi_on_char (pfile, kind, /*ucn_p=*/false, loc);
+                }
+              buffer->cur++;
+            }
+@@ -1734,9 +1881,9 @@ forms_identifier_p (cpp_reader *pfile, i
+          if (__builtin_expect (*buffer->cur == bidi::utf8_start, 0)
+              && warn_bidi_p)
+            {
+-             bidi::kind kind = get_bidi_utf8 (buffer->cur);
+-             maybe_warn_bidi_on_char (pfile, buffer->cur, kind,
+-                                      /*ucn_p=*/false);
++             location_t loc;
++             bidi::kind kind = get_bidi_utf8 (pfile, buffer->cur, &loc);
++             maybe_warn_bidi_on_char (pfile, kind, /*ucn_p=*/false, loc);
+            }
+          if (_cpp_valid_utf8 (pfile, &buffer->cur, buffer->rlimit, 1 + !first,
+                               state, &s))
+@@ -1748,10 +1895,12 @@ forms_identifier_p (cpp_reader *pfile, i
+          buffer->cur += 2;
+          if (warn_bidi_p)
+            {
+-             bidi::kind kind = get_bidi_ucn (buffer->cur,
+-                                             buffer->cur[-1] == 'U');
+-             maybe_warn_bidi_on_char (pfile, buffer->cur, kind,
+-                                      /*ucn_p=*/true);
++             location_t loc;
++             bidi::kind kind = get_bidi_ucn (pfile,
++                                             buffer->cur,
++                                             buffer->cur[-1] == 'U',
++                                             &loc);
++             maybe_warn_bidi_on_char (pfile, kind, /*ucn_p=*/true, loc);
+            }
+          if (_cpp_valid_ucn (pfile, &buffer->cur, buffer->rlimit, 1 + !first,
+                              state, &s, NULL, NULL))
+@@ -2327,12 +2476,15 @@ lex_raw_string (cpp_reader *pfile, cpp_t
+        }
+       else if (__builtin_expect ((unsigned char) c == bidi::utf8_start, 0)
+               && warn_bidi_p)
+-       maybe_warn_bidi_on_char (pfile, pos - 1, get_bidi_utf8 (pos - 1),
+-                                /*ucn_p=*/false);
++       {
++         location_t loc;
++         bidi::kind kind = get_bidi_utf8 (pfile, cur - 1, &loc);
++         maybe_warn_bidi_on_char (pfile, kind, /*ucn_p=*/false, loc);
++       }
+     }
+ 
+   if (warn_bidi_p)
+-    maybe_warn_bidi_on_close (pfile, pos);
++    maybe_warn_bidi_on_close (pfile, cur);
+ 
+   if (CPP_OPTION (pfile, user_literals))
+     {
+@@ -2438,8 +2590,10 @@ lex_string (cpp_reader *pfile, cpp_token
+        {
+          if ((cur[0] == 'u' || cur[0] == 'U') && warn_bidi_p)
+            {
+-             bidi::kind kind = get_bidi_ucn (cur + 1, cur[0] == 'U');
+-             maybe_warn_bidi_on_char (pfile, cur, kind, /*ucn_p=*/true);
++             location_t loc;
++             bidi::kind kind = get_bidi_ucn (pfile, cur + 1, cur[0] == 'U',
++                                             &loc);
++             maybe_warn_bidi_on_char (pfile, kind, /*ucn_p=*/true, loc);
+            }
+          cur++;
+        }
+@@ -2467,8 +2621,9 @@ lex_string (cpp_reader *pfile, cpp_token
+        saw_NUL = true;
+       else if (__builtin_expect (c == bidi::utf8_start, 0) && warn_bidi_p)
+        {
+-         bidi::kind kind = get_bidi_utf8 (cur - 1);
+-         maybe_warn_bidi_on_char (pfile, cur - 1, kind, /*ucn_p=*/false);
++         location_t loc;
++         bidi::kind kind = get_bidi_utf8 (pfile, cur - 1, &loc);
++         maybe_warn_bidi_on_char (pfile, kind, /*ucn_p=*/false, loc);
+        }
+     }
+