Add INLINE_SYSCALL_ERROR_RETURN_VALUE

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.

1 files changed, 25 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/sysdep.h b/sysdeps/unix/sysv/linux/sysdep.h
new file mode 100644
index 0000000000..a7dd887394
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/sysdep.h
@@ -0,0 +1,25 @@
+/* Copyright (C) 2015 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* Set error number and return -1.  A target may choose to return the
+   internal function, __syscall_error, which sets errno and returns -1.
+   We use -1l, instead of -1, so that it can be casted to (void *).  */
+#define INLINE_SYSCALL_ERROR_RETURN_VALUE(err)  \
+  ({						\
+    __set_errno (err);				\
+    -1l;					\
+  })