From patchwork Fri Feb 17 14:47:55 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Adhemerval Zanella Netto X-Patchwork-Id: 19284 Received: (qmail 4945 invoked by alias); 17 Feb 2017 14:48:41 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 4182 invoked by uid 89); 17 Feb 2017 14:48:21 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-25.0 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, RCVD_IN_DNSWL_LOW, SPF_PASS autolearn=ham version=3.3.2 spammy= X-HELO: mail-qt0-f178.google.com X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:cc:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding; bh=TSk92HNqdORuSMZ0braqkVM6dc8R489fIhOhIBT3RnM=; b=bShKFaRikbtopeZLqnz+MTi+Uc+5/Xur765VBcsSZMqnmz0PwJgieRoux6+s7GslxQ MedCcZnwjB+yHQK8lXhZlaFaC/yXSAoEA0RaG2EGU9zg0p7bDI0e2HXGmynbv2c5/MEl bE8+Gb6F0qRCVc3EQLqz6SZpTuue8GhnP3YqE/uCX95U77EK60j6vy6uotU1SNZYw3SH Ij8LxZQXgj4gkEHIXplegPzlsKCoy6svcFtu+CLXaYcld/z+jUo6qzCUbHCdw3ICCHRl xrt133b+9p0j49z+pfcM+tXG6ySrxBPnJ4NWfQzvR+g+M/lhFV3WZ3xMz0RC1J+oLyTt jDbw== X-Gm-Message-State: AMke39n+nqAAbxdhVa6Hx3L2I3izAqpHomeO3/bfMwHzKJFtYMMhxeGUQqZia0G8N4X+G3G0 X-Received: by 10.237.54.1 with SMTP id e1mr7272969qtb.68.1487342880006; Fri, 17 Feb 2017 06:48:00 -0800 (PST) Subject: Re: [PATCH] Rework -fno-omit-frame-pointer support on i386 To: "H.J. Lu" References: <1483966550-21038-1-git-send-email-adhemerval.zanella@linaro.org> Cc: GNU C Library From: Adhemerval Zanella Message-ID: <0e80c379-4c5b-9d00-7331-6c4035fac5e2@linaro.org> Date: Fri, 17 Feb 2017 12:47:55 -0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 MIME-Version: 1.0 In-Reply-To: On 16/02/2017 17:24, H.J. Lu wrote: > On Mon, Jan 9, 2017 at 4:55 AM, Adhemerval Zanella >> +# Check if CFLAGS sets -fno-omit-frame-pointer >> +AC_CACHE_CHECK(for if compiler flags sets -fno-omit-frame-pointer, >> + libc_cv_no_omit_frame_pointer, >> + [cat > conftest.c << EOF >> + void foo (void) { } >> +EOF >> + libc_cv_no_omit_frame_pointer=no >> + if AC_TRY_COMMAND(${CC-cc} $CFLAGS -S conftest.c -o conftest.s 1>&AS_MESSAGE_LOG_FD); then >> + if grep 'push.*%ebp' conftest.s >/dev/null && >> + grep 'pop.*%ebp' conftest.s >/dev/null; then >> + libc_cv_no_omit_frame_pointer=yes >> + fi >> + fi >> + rm -f conftest.c conftest.s >> + ]) > > I prefer something like > > [hjl@gnu-fer something like > > [hjl@gnu-6 tmp]$ cat ebp.c > void > foo (int i) > { > register int reg asm ("ebp") = i; > asm ("# %0" : : "r" (reg)); > } > [hjl@gnu-6 tmp]$ gcc -S -m32 -Os ebp.c > ebp.c: In function ‘foo’: > ebp.c:6:1: error: bp cannot be used in asm here > } > ^ > [hjl@gnu-6 tmp]$ gcc -S -m32 -O2 ebp.c > [hjl@gnu-6 tmp]$ > >> +if test $libc_cv_no_omit_frame_pointer = yes; then >> + AC_DEFINE(NO_OMIT_FRAME_POINTER) >> +fi > > How about something like CAN_USE_REGISTER_ASM_EBP? I implemented both your suggestions in this version: [BZ #21029] * config.h.in [CAN_USE_REGISTER_ASM_EBP]: New define. * sysdeps/unix/sysv/linux/i386/Makefile [$(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. 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..c40db59 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 @@ -611,7 +611,8 @@ struct libc_do_syscall_args #endif /* Consistency check for position-independent code. */ -#if defined __PIC__ && !defined OPTIMIZE_FOR_GCC_5 +#if defined __PIC__ && !defined OPTIMIZE_FOR_GCC_5 \ + && !CAN_USE_REGISTER_ASM_EBP # define check_consistency() \ ({ int __res; \ __asm__ __volatile__ \