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fb1cf10811
For ia32 PIC, the first thing of many syscalls does is to call __x86.get_pc_thunk.reg to load PC into reg in case there is an error, which is required for setting errno. In most cases, there are no errors. But we still call __x86.get_pc_thunk.reg. This patch adds INLINE_SYSCALL_ERROR_RETURN_VALUE so that i386 can optimize setting errno by branching to the internal __syscall_error without PLT. With i386 INLINE_SYSCALL_ERROR_RETURN_VALUE and i386 syscall inlining optimization for GCC 5, for sysdeps/unix/sysv/linux/fchmodat.c with -O2 -march=i686 -mtune=generic, GCC 5.2 now generates: <fchmodat>: 0: push %ebx 1: mov 0x14(%esp),%eax 5: mov 0x8(%esp),%ebx 9: mov 0xc(%esp),%ecx d: mov 0x10(%esp),%edx 11: test $0xfffffeff,%eax 16: jne 38 <fchmodat+0x38> 18: test $0x1,%ah 1b: jne 48 <fchmodat+0x48> 1d: mov $0x132,%eax 22: call *%gs:0x10 29: cmp $0xfffff000,%eax 2e: ja 58 <fchmodat+0x58> 30: pop %ebx 31: ret 32: lea 0x0(%esi),%esi 38: pop %ebx 39: mov $0xffffffea,%eax 3e: jmp 3f <fchmodat+0x3f> 3f: R_386_PC32 __syscall_error 43: nop 44: lea 0x0(%esi,%eiz,1),%esi 48: pop %ebx 49: mov $0xffffffa1,%eax 4e: jmp 4f <fchmodat+0x4f> 4f: R_386_PC32 __syscall_error 53: nop 54: lea 0x0(%esi,%eiz,1),%esi 58: pop %ebx 59: jmp 5a <fchmodat+0x5a> 5a: R_386_PC32 __syscall_error instead of <fchmodat>: 0: sub $0x8,%esp 3: mov 0x18(%esp),%eax 7: mov %ebx,(%esp) a: call b <fchmodat+0xb> b: R_386_PC32 __x86.get_pc_thunk.bx f: add $0x2,%ebx 11: R_386_GOTPC _GLOBAL_OFFSET_TABLE_ 15: mov %edi,0x4(%esp) 19: test $0xfffffeff,%eax 1e: jne 70 <fchmodat+0x70> 20: test $0x1,%ah 23: jne 88 <fchmodat+0x88> 25: mov 0x14(%esp),%edx 29: mov 0x10(%esp),%ecx 2d: mov 0xc(%esp),%edi 31: xchg %ebx,%edi 33: mov $0x132,%eax 38: call *%gs:0x10 3f: xchg %edi,%ebx 41: cmp $0xfffff000,%eax 46: ja 58 <fchmodat+0x58> 48: mov (%esp),%ebx 4b: mov 0x4(%esp),%edi 4f: add $0x8,%esp 52: ret 53: nop 54: lea 0x0(%esi,%eiz,1),%esi 58: mov 0x0(%ebx),%edx 5a: R_386_TLS_GOTIE __libc_errno 5e: neg %eax 60: mov %eax,%gs:(%edx) 63: mov $0xffffffff,%eax 68: jmp 48 <fchmodat+0x48> 6a: lea 0x0(%esi),%esi 70: mov 0x0(%ebx),%eax 72: R_386_TLS_GOTIE __libc_errno 76: movl $0x16,%gs:(%eax) 7d: mov $0xffffffff,%eax 82: jmp 48 <fchmodat+0x48> 84: lea 0x0(%esi,%eiz,1),%esi 88: mov 0x0(%ebx),%eax 8a: R_386_TLS_GOTIE __libc_errno 8e: movl $0x5f,%gs:(%eax) 95: mov $0xffffffff,%eax 9a: jmp 48 <fchmodat+0x48> * sysdeps/unix/sysv/linux/sysdep.h: New file. * sysdeps/unix/sysv/linux/i386/sysdep.c: Likewise. * sysdeps/unix/sysv/linux/alpha/sysdep.h: Include <sysdeps/unix/sysv/linux/sysdep.h>. * sysdeps/unix/sysv/linux/arm/sysdep.h: Likewise. * sysdeps/unix/sysv/linux/generic/sysdep.h: Likewise. * sysdeps/unix/sysv/linux/hppa/sysdep.h: Likewise. * sysdeps/unix/sysv/linux/ia64/sysdep.h: Likewise. * sysdeps/unix/sysv/linux/m68k/sysdep.h: Likewise. * sysdeps/unix/sysv/linux/microblaze/sysdep.h: Likewise. * sysdeps/unix/sysv/linux/mips/mips32/sysdep.h: Likewise. * sysdeps/unix/sysv/linux/mips/mips64/n32/sysdep.h: Likewise. * sysdeps/unix/sysv/linux/mips/mips64/n64/sysdep.h: Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep.h: Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep.h: Likewise. * sysdeps/unix/sysv/linux/s390/s390-32/sysdep.h: Likewise. * sysdeps/unix/sysv/linux/s390/s390-64/sysdep.h: Likewise. * sysdeps/unix/sysv/linux/sh/sysdep.h: Likewise. * sysdeps/unix/sysv/linux/sparc/sysdep.h: Likewise. * sysdeps/unix/sysv/linux/x86_64/sysdep.h: Likewise. * sysdeps/unix/sysv/linux/i386/Makefile [$(subdir) == csu] (sysdep-dl-routines): Add sysdep. [$(subdir) == nptl] (libpthread-routines): Likewise. [$(subdir) == rt] (librt-routines): Likewise. * sysdeps/unix/sysv/linux/i386/clone.S (__clone): Don't check PIC when branching to SYSCALL_ERROR_LABEL. * sysdeps/unix/sysv/linux/i386/sysdep.S: Removed. * sysdeps/unix/sysv/linux/i386/sysdep.h: Include <sysdeps/unix/sysv/linux/sysdep.h>. (SYSCALL_ERROR_LABEL): Changed to __syscall_error. (SYSCALL_ERROR_ERRNO): Removed. (SYSCALL_ERROR_HANDLER): Changed to empty. (SYSCALL_ERROR_HANDLER_TLS_STORE): Likewise. (__syscall_error): New prototype. [IS_IN (libc)] (INLINE_SYSCALL): New macro. (INLINE_SYSCALL_ERROR_RETURN_VALUE): Likewise.
44 lines
1.6 KiB
C
44 lines
1.6 KiB
C
/* Copyright (C) 2011-2015 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library. If not, see
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<http://www.gnu.org/licenses/>. */
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#include <bits/wordsize.h>
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#include <kernel-features.h>
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#include <sysdeps/unix/sysdep.h>
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#include <sysdeps/unix/sysv/linux/sysdep.h>
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/* Provide the common name to allow more code reuse. */
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#define __NR__llseek __NR_llseek
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#if __WORDSIZE == 64
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/* By defining the older names, glibc will build syscall wrappers for
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both pread and pread64; sysdeps/unix/sysv/linux/wordsize-64/pread64.c
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will suppress generating any separate code for pread64.c. */
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#define __NR_pread __NR_pread64
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#define __NR_pwrite __NR_pwrite64
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#endif
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/* Provide a dummy argument that can be used to force register
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alignment for register pairs if required by the syscall ABI. */
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#ifdef __ASSUME_ALIGNED_REGISTER_PAIRS
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#define __ALIGNMENT_ARG 0,
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#define __ALIGNMENT_COUNT(a,b) b
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#else
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#define __ALIGNMENT_ARG
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#define __ALIGNMENT_COUNT(a,b) a
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#endif
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