busybox: Update the clang compatibility patch to work with clang 9.xkraj/clang-busybox

Signed-off-by: Khem Raj <raj.khem@gmail.com>

3 files changed, 141 insertions, 28 deletions

diff --git a/recipes-core/busybox/busybox/0001-Turn-ptr_to_globals-and-bb_errno-to-be-non-const.patch b/recipes-core/busybox/busybox/0001-Turn-ptr_to_globals-and-bb_errno-to-be-non-const.patch
new file mode 100644
index 0000000..481b125
--- /dev/null
+++ b/recipes-core/busybox/busybox/0001-Turn-ptr_to_globals-and-bb_errno-to-be-non-const.patch
@@ -0,0 +1,137 @@
+From c7580fdb4be69a872291ccf22334091cace749fc Mon Sep 17 00:00:00 2001
+From: Khem Raj <raj.khem@gmail.com>
+Date: Wed, 16 Jan 2019 22:39:24 -0800
+Subject: [PATCH] Turn ptr_to_globals and bb_errno to be non const
+
+writing to a const variable is undefined behavior
+
+This is undefined as per (C99 6.7.3 paragraph 5) see [1]
+
+errno and ptr_to_globals is written to in code, this fails with
+segfaults when compiled with clang
+
+unsigned FAST_FUNC bb_strtou(const char *arg, char **endp, int base)
+{
+      unsigned long v;
+      char *endptr;
+
+      if (!endp) endp = &endptr;
+      *endp = (char*) arg;
+
+      if (!isalnum(arg[0])) return ret_ERANGE();
+      errno = 0;
+      v = strtoul(arg, endp, base);
+      if (v > UINT_MAX) return ret_ERANGE();
+      return handle_errors(v, endp);
+  }
+
+without 'const' ( working code )
+
+Dump of assembler code for function bb_strtou:
+   0x0000555555568298 <+0>:     push   %rbx
+   0x0000555555568299 <+1>:     sub    $0x10,%rsp
+   0x000055555556829d <+5>:     test   %rsi,%rsi
+   0x00005555555682a0 <+8>:     lea    0x8(%rsp),%rbx
+   0x00005555555682a5 <+13>:    cmovne %rsi,%rbx
+   0x00005555555682a9 <+17>:    mov    %rdi,(%rbx)
+   0x00005555555682ac <+20>:    mov    (%rdi),%al
+   0x00005555555682ae <+22>:    lea    -0x30(%rax),%ecx
+   0x00005555555682b1 <+25>:    cmp    $0xa,%cl
+   0x00005555555682b4 <+28>:    jb     0x5555555682be <bb_strtou+38>
+   0x00005555555682b6 <+30>:    or     $0x20,%al
+   0x00005555555682b8 <+32>:    add    $0x9f,%al
+   0x00005555555682ba <+34>:    cmp    $0x1a,%al
+   0x00005555555682bc <+36>:    jae    0x5555555682dc <bb_strtou+68>
+   0x00005555555682be <+38>:    mov    0x107da3(%rip),%rax        # 0x555555670068 <bb_errno>
+=> 0x00005555555682c5 <+45>:    movl   $0x0,(%rax)
+   0x00005555555682cb <+51>:    mov    %rbx,%rsi
+   0x00005555555682ce <+54>:    callq  0x555555564310 <strtoul@plt>
+   0x00005555555682d3 <+59>:    mov    %rax,%rcx
+   0x00005555555682d6 <+62>:    shr    $0x20,%rcx
+   0x00005555555682da <+66>:    je     0x5555555682f0 <bb_strtou+88>
+   0x00005555555682dc <+68>:    mov    0x107d85(%rip),%rax        # 0x555555670068 <bb_errno>
+   0x00005555555682e3 <+75>:    movl   $0x22,(%rax)
+   0x00005555555682e9 <+81>:    mov    $0xffffffff,%eax
+   0x00005555555682ee <+86>:    jmp    0x5555555682fb <bb_strtou+99>
+   0x00005555555682f0 <+88>:    mov    %rax,%rdi
+   0x00005555555682f3 <+91>:    mov    %rbx,%rsi
+   0x00005555555682f6 <+94>:    callq  0x5555555681e8 <handle_errors>
+   0x00005555555682fb <+99>:    add    $0x10,%rsp
+   0x00005555555682ff <+103>:   pop    %rbx
+   0x0000555555568300 <+104>:   retq
+
+here address of bb_errno is valid rax = 0x7ffff7cac6c0
+
+with 'const' ( non-working code )
+
+Dump of assembler code for function bb_strtou:
+   0x00005555555682a4 <+0>:     push   %r14
+   0x00005555555682a6 <+2>:     push   %rbx
+   0x00005555555682a7 <+3>:     push   %rax
+   0x00005555555682a8 <+4>:     test   %rsi,%rsi
+   0x00005555555682ab <+7>:     mov    %rsp,%rbx
+   0x00005555555682ae <+10>:    cmovne %rsi,%rbx
+   0x00005555555682b2 <+14>:    mov    %rdi,(%rbx)
+   0x00005555555682b5 <+17>:    mov    (%rdi),%al
+   0x00005555555682b7 <+19>:    lea    -0x30(%rax),%ecx
+   0x00005555555682ba <+22>:    cmp    $0xa,%cl
+   0x00005555555682bd <+25>:    jb     0x5555555682d6 <bb_strtou+50>
+   0x00005555555682bf <+27>:    or     $0x20,%al
+   0x00005555555682c1 <+29>:    add    $0x9f,%al
+   0x00005555555682c3 <+31>:    cmp    $0x1a,%al
+   0x00005555555682c5 <+33>:    jb     0x5555555682d6 <bb_strtou+50>
+   0x00005555555682c7 <+35>:    mov    0x107d9a(%rip),%rax        # 0x555555670068 <bb_errno>
+   0x00005555555682ce <+42>:    movl   $0x22,(%rax)
+   0x00005555555682d4 <+48>:    jmp    0x5555555682fc <bb_strtou+88>
+   0x00005555555682d6 <+50>:    mov    0x107d8b(%rip),%r14        # 0x555555670068 <bb_errno>
+=> 0x00005555555682dd <+57>:    movl   $0x0,(%r14)
+   0x00005555555682e4 <+64>:    mov    %rbx,%rsi
+   0x00005555555682e7 <+67>:    callq  0x555555564300 <strtoul@plt>
+   0x00005555555682ec <+72>:    mov    %rax,%rcx
+   0x00005555555682ef <+75>:    shr    $0x20,%rcx
+   0x00005555555682f3 <+79>:    je     0x555555568303 <bb_strtou+95>
+   0x00005555555682f5 <+81>:    movl   $0x22,(%r14)
+   0x00005555555682fc <+88>:    mov    $0xffffffff,%eax
+   0x0000555555568301 <+93>:    jmp    0x55555556830e <bb_strtou+106>
+   0x0000555555568303 <+95>:    mov    %rax,%rdi
+   0x0000555555568306 <+98>:    mov    %rbx,%rsi
+   0x0000555555568309 <+101>:   callq  0x5555555681f4 <handle_errors>
+   0x000055555556830e <+106>:   add    $0x8,%rsp
+   0x0000555555568312 <+110>:   pop    %rbx
+   0x0000555555568313 <+111>:   pop    %r14
+   0x0000555555568315 <+113>:   retq
+
+r14 is 0x0 and writing to this ofcourse ends up in segfault
+
+[1] https://bugs.llvm.org/show_bug.cgi?id=39919
+
+Signed-off-by: Khem Raj <raj.khem@gmail.com>
+---
+ include/libbb.h | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/include/libbb.h b/include/libbb.h
+index 111d1b790..a52265e77 100644
+--- a/include/libbb.h
++++ b/include/libbb.h
+@@ -341,7 +341,7 @@ struct BUG_off_t_size_is_misdetected {
+ #if defined(__GLIBC__)
+ /* glibc uses __errno_location() to get a ptr to errno */
+ /* We can just memorize it once - no multithreading in busybox :) */
+-extern int *const bb_errno;
++extern int *bb_errno;
+ #undef errno
+ #define errno (*bb_errno)
+ #endif
+@@ -2152,7 +2152,7 @@ struct globals;
+ /* '*const' ptr makes gcc optimize code much better.
+  * Magic prevents ptr_to_globals from going into rodata.
+  * If you want to assign a value, use SET_PTR_TO_GLOBALS(x) */
+-extern struct globals *const ptr_to_globals;
++extern struct globals *ptr_to_globals;
+ /* At least gcc 3.4.6 on mipsel system needs optimization barrier */
+ #define barrier() __asm__ __volatile__("":::"memory")
+ #define SET_PTR_TO_GLOBALS(x) do { \
+-- 
+2.22.0
+
diff --git a/recipes-core/busybox/busybox/0001-writing-to-a-const-variable-is-undefined-behavior-C9.patch b/recipes-core/busybox/busybox/0001-writing-to-a-const-variable-is-undefined-behavior-C9.patch
deleted file mode 100644
index 6b933da..0000000
--- a/recipes-core/busybox/busybox/0001-writing-to-a-const-variable-is-undefined-behavior-C9.patch
+++ /dev/null
@@ -1,27 +0,0 @@
-From 64c27d12dab4d5a31103f48773733f17c84b0a77 Mon Sep 17 00:00:00 2001
-From: Khem Raj <raj.khem@gmail.com>
-Date: Wed, 16 Jan 2019 22:39:24 -0800
-Subject: [PATCH] writing to a const variable is undefined behavior (C99 6.7.3
- paragraph 5).
-
-Signed-off-by: Khem Raj <raj.khem@gmail.com>
----
- include/libbb.h | 2 +-
- 1 file changed, 1 insertion(+), 1 deletion(-)
-
-diff --git a/include/libbb.h b/include/libbb.h
-index 3366df30f..6b925eb2d 100644
---- a/include/libbb.h
-+++ b/include/libbb.h
-@@ -2092,7 +2092,7 @@ struct globals;
- /* '*const' ptr makes gcc optimize code much better.
-  * Magic prevents ptr_to_globals from going into rodata.
-  * If you want to assign a value, use SET_PTR_TO_GLOBALS(x) */
--extern struct globals *const ptr_to_globals;
-+extern struct globals *ptr_to_globals;
- /* At least gcc 3.4.6 on mipsel system needs optimization barrier */
- #define barrier() __asm__ __volatile__("":::"memory")
- #define SET_PTR_TO_GLOBALS(x) do { \
--- 
-2.20.1
-
diff --git a/recipes-core/busybox/busybox_%.bbappend b/recipes-core/busybox/busybox_%.bbappend
index a4c90f4..2187660 100644
--- a/recipes-core/busybox/busybox_%.bbappend
+++ b/recipes-core/busybox/busybox_%.bbappend
@@ -1,3 +1,6 @@
 FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
-SRC_URI_append_toolchain-clang = " file://0001-writing-to-a-const-variable-is-undefined-behavior-C9.patch"
+SRC_URI_append_toolchain-clang = "\
+    file://0001-Turn-ptr_to_globals-and-bb_errno-to-be-non-const.patch \
+    "
+
 TOOLCHAIN_x86 = "gcc"