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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. |
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| .. | ||
| aarch64 | ||
| alpha | ||
| arm | ||
| generic | ||
| gnu | ||
| hppa | ||
| i386 | ||
| ia64 | ||
| ieee754 | ||
| init_array | ||
| m68k | ||
| mach | ||
| microblaze | ||
| mips | ||
| nacl | ||
| nios2 | ||
| nptl | ||
| posix | ||
| powerpc | ||
| pthread | ||
| s390 | ||
| sh | ||
| sparc | ||
| tile | ||
| unix | ||
| wordsize-32 | ||
| wordsize-64 | ||
| x86 | ||
| x86_64 | ||