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, 23 insertions, 55 deletions

diff --git a/sysdeps/unix/sysv/linux/i386/sysdep.h b/sysdeps/unix/sysv/linux/i386/sysdep.h
index d76aca50d6..3cf927a24b 100644
--- a/sysdeps/unix/sysv/linux/i386/sysdep.h
+++ b/sysdeps/unix/sysv/linux/i386/sysdep.h
@@ -20,6 +20,7 @@
 #define _LINUX_I386_SYSDEP_H 1
 
 /* There is some commonality.  */
+#include <sysdeps/unix/sysv/linux/sysdep.h>
 #include <sysdeps/unix/i386/sysdep.h>
 /* Defines RTLD_PRIVATE_ERRNO and USE_DL_SYSINFO.  */
 #include <dl-sysdep.h>
@@ -55,11 +56,7 @@
 
 /* We don't want the label for the error handle to be global when we define
    it here.  */
-#ifdef PIC
-# define SYSCALL_ERROR_LABEL 0f
-#else
-# define SYSCALL_ERROR_LABEL syscall_error
-#endif
+#define SYSCALL_ERROR_LABEL __syscall_error
 
 #undef	PSEUDO
 #define	PSEUDO(name, syscall_name, args)				      \
@@ -100,55 +97,7 @@
 
 #define ret_ERRVAL ret
 
-#ifndef PIC
-# define SYSCALL_ERROR_HANDLER	/* Nothing here; code in sysdep.S is used.  */
-#else
-
-# if RTLD_PRIVATE_ERRNO
-#  define SYSCALL_ERROR_HANDLER						      \
-0:SETUP_PIC_REG(cx);							      \
-  addl $_GLOBAL_OFFSET_TABLE_, %ecx;					      \
-  negl %eax;								      \
-  movl %eax, rtld_errno@GOTOFF(%ecx);					      \
-  orl $-1, %eax;							      \
-  ret;
-
-# elif defined _LIBC_REENTRANT
-
-#  if IS_IN (libc)
-#   define SYSCALL_ERROR_ERRNO __libc_errno
-#  else
-#   define SYSCALL_ERROR_ERRNO errno
-#  endif
-#  define SYSCALL_ERROR_HANDLER					      \
-0:SETUP_PIC_REG (cx);							      \
-  addl $_GLOBAL_OFFSET_TABLE_, %ecx;					      \
-  movl SYSCALL_ERROR_ERRNO@GOTNTPOFF(%ecx), %ecx;			      \
-  negl %eax;								      \
-  SYSCALL_ERROR_HANDLER_TLS_STORE (%eax, %ecx);				      \
-  orl $-1, %eax;							      \
-  ret;
-#  ifndef NO_TLS_DIRECT_SEG_REFS
-#   define SYSCALL_ERROR_HANDLER_TLS_STORE(src, destoff)		      \
-  movl src, %gs:(destoff)
-#  else
-#   define SYSCALL_ERROR_HANDLER_TLS_STORE(src, destoff)		      \
-  addl %gs:0, destoff;							      \
-  movl src, (destoff)
-#  endif
-# else
-/* Store (- %eax) into errno through the GOT.  */
-#  define SYSCALL_ERROR_HANDLER						      \
-0:SETUP_PIC_REG(cx);							      \
-  addl $_GLOBAL_OFFSET_TABLE_, %ecx;					      \
-  negl %eax;								      \
-  movl errno@GOT(%ecx), %ecx;						      \
-  movl %eax, (%ecx);							      \
-  orl $-1, %eax;							      \
-  ret;
-# endif	/* _LIBC_REENTRANT */
-#endif	/* PIC */
-
+#define SYSCALL_ERROR_HANDLER	/* Nothing here; code in sysdep.c is used.  */
 
 /* The original calling convention for system calls on Linux/i386 is
    to use int $0x80.  */
@@ -275,6 +224,9 @@
 
 #else	/* !__ASSEMBLER__ */
 
+extern int __syscall_error (int)
+  attribute_hidden __attribute__ ((__regparm__ (1)));
+
 /* We need some help from the assembler to generate optimal code.  We
    define some macros here which later will be used.  */
 asm (".L__X'%ebx = 1\n\t"
@@ -318,7 +270,15 @@ struct libc_do_syscall_args
 /* Define a macro which expands inline into the wrapper code for a system
    call.  */
 #undef INLINE_SYSCALL
-#define INLINE_SYSCALL(name, nr, args...) \
+#if IS_IN (libc)
+# define INLINE_SYSCALL(name, nr, args...) \
+  ({									      \
+    unsigned int resultvar = INTERNAL_SYSCALL (name, , nr, args);	      \
+    __glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (resultvar, ))		      \
+    ? __syscall_error (-INTERNAL_SYSCALL_ERRNO (resultvar, ))		      \
+    : (int) resultvar; })
+#else
+# define INLINE_SYSCALL(name, nr, args...) \
   ({									      \
     unsigned int resultvar = INTERNAL_SYSCALL (name, , nr, args);	      \
     if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (resultvar, )))	      \
@@ -327,6 +287,14 @@ struct libc_do_syscall_args
 	resultvar = 0xffffffff;						      \
       }									      \
     (int) resultvar; })
+#endif
+
+/* Set error number and return -1.  Return the internal function,
+   __syscall_error, which sets errno from the negative error number
+   and returns -1, to avoid PIC.  */
+#undef INLINE_SYSCALL_ERROR_RETURN_VALUE
+#define INLINE_SYSCALL_ERROR_RETURN_VALUE(resultvar) \
+  __syscall_error (-(resultvar))
 
 /* List of system calls which are supported as vsyscalls.  */
 # define HAVE_CLOCK_GETTIME_VSYSCALL    1