From 1ea003d4fccc4646fd1848a182405a1c7000ab18 Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Sun, 8 Jan 2017 11:38:23 -0200 Subject: [PATCH 28/28] Rework -fno-omit-frame-pointer support on i386 Commit 6b1df8b27f fixed the -OS build issue on i386 (BZ#20729) by expliciting disabling frame pointer (-fomit-frame-pointer) on the faulty objects. Although it does fix the issue, it is a subpar workaround that adds complexity in build process (a rule for each object to add the required compiler option and pontentially more rules for objects that call {INLINE,INTERNAL}_SYSCALL) and does not allow the implementations to get all the possible debug/calltrack information possible (used mainly in debuggers and performance measurement tools). This patch fixes it by adding an explicit configure check to see if -fno-omit-frame-pointer is set and to act accordingly (set or not OPTIMIZE_FOR_GCC_5). The make rules is simplified and only one is required: to add libc-do-syscall on loader due mmap (which will be empty anyway for default build with -fomit-frame-pointer). Checked on i386-linux-gnu with GCC 6.2.1 with CFLAGS sets as '-Os', '-O2 -fno-omit-frame-pointer', and '-O2 -fomit-frame-pointer'. For '-Os' the testsuite issues described by BZ#19463 and BZ#15105 still applied. It fixes BZ #21029, although it is marked as duplicated of #20729 (I reopened to track this cleanup). [BZ #21029] * config.h.in [CAN_USE_REGISTER_ASM_EBP]: New define. * sysdeps/unix/sysv/linux/i386/Makefile [$(subdir) = elf] (sysdep-dl-routines): Add libc-do-syscall. (uses-6-syscall-arguments): Remove. [$(subdir) = misc] (CFLAGS-epoll_pwait.o): Likewise. [$(subdir) = misc] (CFLAGS-epoll_pwait.os): Likewise. [$(subdir) = misc] (CFLAGS-mmap.o): Likewise. [$(subdir) = misc] (CFLAGS-mmap.os): Likewise. [$(subdir) = misc] (CFLAGS-mmap64.o): Likewise. [$(subdir) = misc] (CFLAGS-mmap64.os): Likewise. [$(subdir) = misc] (CFLAGS-pselect.o): Likewise. [$(subdir) = misc] (cflags-pselect.o): Likewise. [$(subdir) = misc] (cflags-pselect.os): Likewise. [$(subdir) = misc] (cflags-rtld-mmap.os): Likewise. [$(subdir) = sysvipc] (cflags-semtimedop.o): Likewise. [$(subdir) = sysvipc] (cflags-semtimedop.os): Likewise. [$(subdir) = io] (CFLAGS-posix_fadvise64.o): Likewise. [$(subdir) = io] (CFLAGS-posix_fadvise64.os): Likewise. [$(subdir) = io] (CFLAGS-posix_fallocate.o): Likewise. [$(subdir) = io] (CFLAGS-posix_fallocate.os): Likewise. [$(subdir) = io] (CFLAGS-posix_fallocate64.o): Likewise. [$(subdir) = io] (CFLAGS-posix_fallocate64.os): Likewise. [$(subdir) = io] (CFLAGS-sync_file_range.o): Likewise. [$(subdir) = io] (CFLAGS-sync_file_range.os): Likewise. [$(subdir) = io] (CFLAGS-fallocate.o): Likewise. [$(subdir) = io] (CFLAGS-fallocate.os): Likewise. [$(subdir) = io] (CFLAGS-fallocate64.o): Likewise. [$(subdir) = io] (CFLAGS-fallocate64.os): Likewise. [$(subdir) = nptl] (CFLAGS-pthread_rwlock_timedrdlock.o): Likewise. [$(subdir) = nptl] (CFLAGS-pthread_rwlock_timedrdlock.os): Likewise. [$(subdir) = nptl] (CFLAGS-pthread_rwlock_timedrwlock.o): Likewise. [$(subdir) = nptl] (CFLAGS-pthread_rwlock_timedrwlock.os): Likewise. [$(subdir) = nptl] (CFLAGS-sem_wait.o): Likewise. [$(subdir) = nptl] (CFLAGS-sem_wait.os): Likewise. [$(subdir) = nptl] (CFLAGS-sem_timedwait.o): Likewise. [$(subdir) = nptl] (CFLAGS-sem_timedwait.os): Likewise. * sysdeps/unix/sysv/linux/i386/configure.ac: Add check if compiler allows ebp on inline assembly. * sysdeps/unix/sysv/linux/i386/configure: Regenerate. * sysdeps/unix/sysv/linux/i386/sysdep.h (OPTIMIZE_FOR_GCC_5): Set if CAN_USE_REGISTER_ASM_EBP is set. (check_consistency): Likewise. Upstream-Status: Backport https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=3b33d6ed6096c1d20d05a650b06026d673f7399a Signed-off-by: Andre McCurdy --- config.h.in | 4 ++++ sysdeps/unix/sysv/linux/i386/Makefile | 39 +------------------------------ sysdeps/unix/sysv/linux/i386/configure | 39 +++++++++++++++++++++++++++++++ sysdeps/unix/sysv/linux/i386/configure.ac | 17 ++++++++++++++ sysdeps/unix/sysv/linux/i386/sysdep.h | 6 ++--- 5 files changed, 64 insertions(+), 41 deletions(-) diff --git a/config.h.in b/config.h.in index 7bfe923..fb2cc51 100644 --- a/config.h.in +++ b/config.h.in @@ -259,4 +259,8 @@ /* Build glibc with tunables support. */ #define HAVE_TUNABLES 0 +/* Some compiler options may now allow to use ebp in __asm__ (used mainly + in i386 6 argument syscall issue). */ +#define CAN_USE_REGISTER_ASM_EBP 0 + #endif diff --git a/sysdeps/unix/sysv/linux/i386/Makefile b/sysdeps/unix/sysv/linux/i386/Makefile index 9609752..6aac0df 100644 --- a/sysdeps/unix/sysv/linux/i386/Makefile +++ b/sysdeps/unix/sysv/linux/i386/Makefile @@ -1,47 +1,18 @@ # The default ABI is 32. default-abi := 32 -# %ebp is used to pass the 6th argument to system calls, so these -# system calls are incompatible with a frame pointer. -uses-6-syscall-arguments = -fomit-frame-pointer - ifeq ($(subdir),misc) sysdep_routines += ioperm iopl vm86 -CFLAGS-epoll_pwait.o += $(uses-6-syscall-arguments) -CFLAGS-epoll_pwait.os += $(uses-6-syscall-arguments) -CFLAGS-mmap.o += $(uses-6-syscall-arguments) -CFLAGS-mmap.os += $(uses-6-syscall-arguments) -CFLAGS-mmap64.o += $(uses-6-syscall-arguments) -CFLAGS-mmap64.os += $(uses-6-syscall-arguments) -CFLAGS-pselect.o += $(uses-6-syscall-arguments) -CFLAGS-pselect.os += $(uses-6-syscall-arguments) -CFLAGS-rtld-mmap.os += $(uses-6-syscall-arguments) -endif - -ifeq ($(subdir),sysvipc) -CFLAGS-semtimedop.o += $(uses-6-syscall-arguments) -CFLAGS-semtimedop.os += $(uses-6-syscall-arguments) endif ifeq ($(subdir),elf) +sysdep-dl-routines += libc-do-syscall sysdep-others += lddlibc4 install-bin += lddlibc4 endif ifeq ($(subdir),io) sysdep_routines += libc-do-syscall -CFLAGS-posix_fadvise64.o += $(uses-6-syscall-arguments) -CFLAGS-posix_fadvise64.os += $(uses-6-syscall-arguments) -CFLAGS-posix_fallocate.o += $(uses-6-syscall-arguments) -CFLAGS-posix_fallocate.os += $(uses-6-syscall-arguments) -CFLAGS-posix_fallocate64.o += $(uses-6-syscall-arguments) -CFLAGS-posix_fallocate64.os += $(uses-6-syscall-arguments) -CFLAGS-sync_file_range.o += $(uses-6-syscall-arguments) -CFLAGS-sync_file_range.os += $(uses-6-syscall-arguments) -CFLAGS-fallocate.o += $(uses-6-syscall-arguments) -CFLAGS-fallocate.os += $(uses-6-syscall-arguments) -CFLAGS-fallocate64.o += $(uses-6-syscall-arguments) -CFLAGS-fallocate64.os += $(uses-6-syscall-arguments) endif ifeq ($(subdir),nptl) @@ -61,14 +32,6 @@ ifeq ($(subdir),nptl) # pull in __syscall_error routine libpthread-routines += sysdep libpthread-shared-only-routines += sysdep -CFLAGS-pthread_rwlock_timedrdlock.o += $(uses-6-syscall-arguments) -CFLAGS-pthread_rwlock_timedrdlock.os += $(uses-6-syscall-arguments) -CFLAGS-pthread_rwlock_timedwrlock.o += $(uses-6-syscall-arguments) -CFLAGS-pthread_rwlock_timedwrlock.os += $(uses-6-syscall-arguments) -CFLAGS-sem_wait.o += $(uses-6-syscall-arguments) -CFLAGS-sem_wait.os += $(uses-6-syscall-arguments) -CFLAGS-sem_timedwait.o += $(uses-6-syscall-arguments) -CFLAGS-sem_timedwait.os += $(uses-6-syscall-arguments) endif ifeq ($(subdir),rt) diff --git a/sysdeps/unix/sysv/linux/i386/configure b/sysdeps/unix/sysv/linux/i386/configure index eb72659..ae2c356 100644 --- a/sysdeps/unix/sysv/linux/i386/configure +++ b/sysdeps/unix/sysv/linux/i386/configure @@ -3,5 +3,44 @@ arch_minimum_kernel=2.6.32 +# Check if CFLAGS allows compiler to use ebp register in inline assembly. + +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if compiler flags allows ebp in inline assembly" >&5 +$as_echo_n "checking if compiler flags allows ebp in inline assembly... " >&6; } +if ${libc_cv_can_use_register_asm_ebp+:} false; then : + $as_echo_n "(cached) " >&6 +else + +cat confdefs.h - <<_ACEOF >conftest.$ac_ext +/* end confdefs.h. */ + + void foo (int i) + { + register int reg asm ("ebp") = i; + asm ("# %0" : : "r" (reg)); + } +int +main () +{ + + ; + return 0; +} +_ACEOF +if ac_fn_c_try_compile "$LINENO"; then : + libc_cv_can_use_register_asm_ebp=yes +else + libc_cv_can_use_register_asm_ebp=no +fi +rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext + +fi +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_can_use_register_asm_ebp" >&5 +$as_echo "$libc_cv_can_use_register_asm_ebp" >&6; } +if test $libc_cv_can_use_register_asm_ebp = yes; then + $as_echo "#define CAN_USE_REGISTER_ASM_EBP 1" >>confdefs.h + +fi + libc_cv_gcc_unwind_find_fde=yes ldd_rewrite_script=sysdeps/unix/sysv/linux/ldd-rewrite.sed diff --git a/sysdeps/unix/sysv/linux/i386/configure.ac b/sysdeps/unix/sysv/linux/i386/configure.ac index 1a11da6..1cd632e 100644 --- a/sysdeps/unix/sysv/linux/i386/configure.ac +++ b/sysdeps/unix/sysv/linux/i386/configure.ac @@ -3,5 +3,22 @@ GLIBC_PROVIDES dnl See aclocal.m4 in the top level source directory. arch_minimum_kernel=2.6.32 +# Check if CFLAGS allows compiler to use ebp register in inline assembly. +AC_CACHE_CHECK([if compiler flags allows ebp in inline assembly], + libc_cv_can_use_register_asm_ebp, [ +AC_COMPILE_IFELSE( + [AC_LANG_PROGRAM([ + void foo (int i) + { + register int reg asm ("ebp") = i; + asm ("# %0" : : "r" (reg)); + }])], + [libc_cv_can_use_register_asm_ebp=yes], + [libc_cv_can_use_register_asm_ebp=no]) +]) +if test $libc_cv_can_use_register_asm_ebp = yes; then + AC_DEFINE(CAN_USE_REGISTER_ASM_EBP) +fi + libc_cv_gcc_unwind_find_fde=yes ldd_rewrite_script=sysdeps/unix/sysv/linux/ldd-rewrite.sed diff --git a/sysdeps/unix/sysv/linux/i386/sysdep.h b/sysdeps/unix/sysv/linux/i386/sysdep.h index baf4642..449b23e 100644 --- a/sysdeps/unix/sysv/linux/i386/sysdep.h +++ b/sysdeps/unix/sysv/linux/i386/sysdep.h @@ -44,9 +44,9 @@ /* Since GCC 5 and above can properly spill %ebx with PIC when needed, we can inline syscalls with 6 arguments if GCC 5 or above is used to compile glibc. Disable GCC 5 optimization when compiling for - profiling since asm ("ebp") can't be used to put the 6th argument - in %ebp for syscall. */ -#if __GNUC_PREREQ (5,0) && !defined PROF + profiling or when -fno-omit-frame-pointer is used since asm ("ebp") + can't be used to put the 6th argument in %ebp for syscall. */ +#if __GNUC_PREREQ (5,0) && !defined PROF && CAN_USE_REGISTER_ASM_EBP # define OPTIMIZE_FOR_GCC_5 #endif -- 1.9.1