mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-22 13:00:06 +00:00
Optimize i386 syscall inlining for GCC 5
Since GCC 5 and above can properly spill %ebx when needed, we can inline syscalls with 6 arguments if GCC 5 or above is used to compile glibc. This patch rewrites INTERNAL_SYSCALL macros and skips __libc_do_syscall for GCC 5. For sysdeps/unix/sysv/linux/i386/brk.c, with -O2 -march=i686 -mtune=generic, GCC 5.2 now generates: <__brk>: 0: push %ebx 1: mov $0x2d,%eax 6: mov 0x8(%esp),%ebx a: call b <__brk+0xb> b: R_386_PC32 __x86.get_pc_thunk.dx f: add $0x2,%edx 11: R_386_GOTPC _GLOBAL_OFFSET_TABLE_ 15: call *%gs:0x10 1c: mov 0x0(%edx),%edx 1e: R_386_GOT32 __curbrk 22: cmp %eax,%ebx 24: mov %eax,(%edx) 26: ja 30 <__brk+0x30> 28: xor %eax,%eax 2a: pop %ebx 2b: ret instead of <__brk>: 0: push %ebx 1: mov 0x8(%esp),%ecx 5: call 6 <__brk+0x6> 6: R_386_PC32 __x86.get_pc_thunk.bx a: add $0x2,%ebx c: R_386_GOTPC _GLOBAL_OFFSET_TABLE_ 10: xchg %ecx,%ebx 12: mov $0x2d,%eax 17: call *%gs:0x10 1e: xchg %ecx,%ebx 20: mov %eax,%edx 22: mov 0x0(%ebx),%eax 24: R_386_GOT32 __curbrk 28: mov %edx,(%eax) 2a: xor %eax,%eax 2c: cmp %edx,%ecx 2e: ja 38 <__brk+0x38> 30: pop %ebx 31: ret The new one is shorter by 2 instructions. * sysdeps/unix/sysv/linux/i386/libc-do-syscall.S (__libc_do_syscall): Defined only if !__GNUC_PREREQ (5,0). * sysdeps/unix/sysv/linux/i386/sysdep.h: Define assembler macros only if !__GNUC_PREREQ (5,0). (INTERNAL_SYSCALL_MAIN_6): Optimize for GCC 5. (INTERNAL_SYSCALL_MAIN_INLINE): Likewise. (INTERNAL_SYSCALL_NCS): Likewise. (LOADREGS_0): New macro for GCC 5. (ASMARGS_0): Likewise. (LOADREGS_1): Likewise. (ASMARGS_1): Likewise. (LOADREGS_2): Likewise. (ASMARGS_2): Likewise. (LOADREGS_3): Likewise. (ASMARGS_3): Likewise. (LOADREGS_4): Likewise. (ASMARGS_4): Likewise. (LOADREGS_5): Likewise. (ASMARGS_5): Likewise. (LOADREGS_6): Likewise. (ASMARGS_6): Likewise.
This commit is contained in:
H.J. Lu
parent
83c01ab32b
commit
98ad631cd0
24
ChangeLog
24
ChangeLog
@ -1,3 +1,27 @@
|
||||
2015-10-15 H.J. Lu <hongjiu.lu@intel.com>
|
||||
|
||||
* sysdeps/unix/sysv/linux/i386/libc-do-syscall.S
|
||||
(__libc_do_syscall): Defined only if !__GNUC_PREREQ (5,0).
|
||||
* sysdeps/unix/sysv/linux/i386/sysdep.h: Define assembler macros
|
||||
only if !__GNUC_PREREQ (5,0).
|
||||
(INTERNAL_SYSCALL_MAIN_6): Optimize for GCC 5.
|
||||
(INTERNAL_SYSCALL_MAIN_INLINE): Likewise.
|
||||
(INTERNAL_SYSCALL_NCS): Likewise.
|
||||
(LOADREGS_0): New macro for GCC 5.
|
||||
(ASMARGS_0): Likewise.
|
||||
(LOADREGS_1): Likewise.
|
||||
(ASMARGS_1): Likewise.
|
||||
(LOADREGS_2): Likewise.
|
||||
(ASMARGS_2): Likewise.
|
||||
(LOADREGS_3): Likewise.
|
||||
(ASMARGS_3): Likewise.
|
||||
(LOADREGS_4): Likewise.
|
||||
(ASMARGS_4): Likewise.
|
||||
(LOADREGS_5): Likewise.
|
||||
(ASMARGS_5): Likewise.
|
||||
(LOADREGS_6): Likewise.
|
||||
(ASMARGS_6): Likewise.
|
||||
|
||||
2015-10-15 H.J. Lu <hongjiu.lu@intel.com>
|
||||
|
||||
* sysdeps/unix/sysv/linux/i386/Makefile (CFLAGS-mmap.c): Add
|
||||
|
||||
@ -18,6 +18,8 @@
|
||||
|
||||
#include <sysdep.h>
|
||||
|
||||
#if !__GNUC_PREREQ (5,0)
|
||||
|
||||
/* %eax, %ecx, %edx and %esi contain the values expected by the kernel.
|
||||
%edi points to a structure with the values of %ebx, %edi and %ebp. */
|
||||
|
||||
@ -48,3 +50,4 @@ ENTRY (__libc_do_syscall)
|
||||
cfi_restore (ebx)
|
||||
ret
|
||||
END (__libc_do_syscall)
|
||||
#endif
|
||||
|
||||
@ -227,6 +227,7 @@
|
||||
extern int __syscall_error (int)
|
||||
attribute_hidden __attribute__ ((__regparm__ (1)));
|
||||
|
||||
#if !__GNUC_PREREQ (5,0)
|
||||
/* 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"
|
||||
@ -266,6 +267,7 @@ struct libc_do_syscall_args
|
||||
{
|
||||
int ebx, edi, ebp;
|
||||
};
|
||||
#endif
|
||||
|
||||
/* Define a macro which expands inline into the wrapper code for a system
|
||||
call. */
|
||||
@ -322,6 +324,10 @@ struct libc_do_syscall_args
|
||||
INTERNAL_SYSCALL_MAIN_INLINE(name, err, 5, args)
|
||||
/* Each object using 6-argument inline syscalls must include a
|
||||
definition of __libc_do_syscall. */
|
||||
#if __GNUC_PREREQ (5,0)
|
||||
# define INTERNAL_SYSCALL_MAIN_6(name, err, args...) \
|
||||
INTERNAL_SYSCALL_MAIN_INLINE(name, err, 6, args)
|
||||
#else /* GCC 5 */
|
||||
# define INTERNAL_SYSCALL_MAIN_6(name, err, arg1, arg2, arg3, \
|
||||
arg4, arg5, arg6) \
|
||||
struct libc_do_syscall_args _xv = \
|
||||
@ -336,12 +342,50 @@ struct libc_do_syscall_args
|
||||
: "=a" (resultvar) \
|
||||
: "i" (__NR_##name), "c" (arg2), "d" (arg3), "S" (arg4), "D" (&_xv) \
|
||||
: "memory", "cc")
|
||||
#endif /* GCC 5 */
|
||||
#define INTERNAL_SYSCALL(name, err, nr, args...) \
|
||||
({ \
|
||||
register unsigned int resultvar; \
|
||||
INTERNAL_SYSCALL_MAIN_##nr (name, err, args); \
|
||||
(int) resultvar; })
|
||||
#ifdef I386_USE_SYSENTER
|
||||
# if __GNUC_PREREQ (5,0)
|
||||
# ifdef SHARED
|
||||
# define INTERNAL_SYSCALL_MAIN_INLINE(name, err, nr, args...) \
|
||||
LOADREGS_##nr(args) \
|
||||
asm volatile ( \
|
||||
"call *%%gs:%P2" \
|
||||
: "=a" (resultvar) \
|
||||
: "a" (__NR_##name), "i" (offsetof (tcbhead_t, sysinfo)) \
|
||||
ASMARGS_##nr(args) : "memory", "cc")
|
||||
# define INTERNAL_SYSCALL_NCS(name, err, nr, args...) \
|
||||
({ \
|
||||
register unsigned int resultvar; \
|
||||
LOADREGS_##nr(args) \
|
||||
asm volatile ( \
|
||||
"call *%%gs:%P2" \
|
||||
: "=a" (resultvar) \
|
||||
: "a" (name), "i" (offsetof (tcbhead_t, sysinfo)) \
|
||||
ASMARGS_##nr(args) : "memory", "cc"); \
|
||||
(int) resultvar; })
|
||||
# else
|
||||
# define INTERNAL_SYSCALL_MAIN_INLINE(name, err, nr, args...) \
|
||||
LOADREGS_##nr(args) \
|
||||
asm volatile ( \
|
||||
"call *_dl_sysinfo" \
|
||||
: "=a" (resultvar) \
|
||||
: "a" (__NR_##name) ASMARGS_##nr(args) : "memory", "cc")
|
||||
# define INTERNAL_SYSCALL_NCS(name, err, nr, args...) \
|
||||
({ \
|
||||
register unsigned int resultvar; \
|
||||
LOADREGS_##nr(args) \
|
||||
asm volatile ( \
|
||||
"call *_dl_sysinfo" \
|
||||
: "=a" (resultvar) \
|
||||
: "a" (name) ASMARGS_##nr(args) : "memory", "cc"); \
|
||||
(int) resultvar; })
|
||||
# endif
|
||||
# else /* GCC 5 */
|
||||
# ifdef SHARED
|
||||
# define INTERNAL_SYSCALL_MAIN_INLINE(name, err, nr, args...) \
|
||||
EXTRAVAR_##nr \
|
||||
@ -387,7 +431,25 @@ struct libc_do_syscall_args
|
||||
: "0" (name) ASMFMT_##nr(args) : "memory", "cc"); \
|
||||
(int) resultvar; })
|
||||
# endif
|
||||
# endif /* GCC 5 */
|
||||
#else
|
||||
# if __GNUC_PREREQ (5,0)
|
||||
# define INTERNAL_SYSCALL_MAIN_INLINE(name, err, nr, args...) \
|
||||
LOADREGS_##nr(args) \
|
||||
asm volatile ( \
|
||||
"int $0x80" \
|
||||
: "=a" (resultvar) \
|
||||
: "a" (__NR_##name) ASMARGS_##nr(args) : "memory", "cc")
|
||||
# define INTERNAL_SYSCALL_NCS(name, err, nr, args...) \
|
||||
({ \
|
||||
register unsigned int resultvar; \
|
||||
LOADREGS_##nr(args) \
|
||||
asm volatile ( \
|
||||
"int $0x80" \
|
||||
: "=a" (resultvar) \
|
||||
: "a" (name) ASMARGS_##nr(args) : "memory", "cc"); \
|
||||
(int) resultvar; })
|
||||
# else /* GCC 5 */
|
||||
# define INTERNAL_SYSCALL_MAIN_INLINE(name, err, nr, args...) \
|
||||
EXTRAVAR_##nr \
|
||||
asm volatile ( \
|
||||
@ -408,6 +470,7 @@ struct libc_do_syscall_args
|
||||
: "=a" (resultvar) \
|
||||
: "0" (name) ASMFMT_##nr(args) : "memory", "cc"); \
|
||||
(int) resultvar; })
|
||||
# endif /* GCC 5 */
|
||||
#endif
|
||||
|
||||
#undef INTERNAL_SYSCALL_DECL
|
||||
@ -472,6 +535,36 @@ struct libc_do_syscall_args
|
||||
# define RESTOREARGS_5
|
||||
#endif
|
||||
|
||||
#if __GNUC_PREREQ (5,0)
|
||||
# define LOADREGS_0()
|
||||
# define ASMARGS_0()
|
||||
# define LOADREGS_1(arg1) \
|
||||
LOADREGS_0 ()
|
||||
# define ASMARGS_1(arg1) \
|
||||
ASMARGS_0 (), "b" ((unsigned int) (arg1))
|
||||
# define LOADREGS_2(arg1, arg2) \
|
||||
LOADREGS_1 (arg1)
|
||||
# define ASMARGS_2(arg1, arg2) \
|
||||
ASMARGS_1 (arg1), "c" ((unsigned int) (arg2))
|
||||
# define LOADREGS_3(arg1, arg2, arg3) \
|
||||
LOADREGS_2 (arg1, arg2)
|
||||
# define ASMARGS_3(arg1, arg2, arg3) \
|
||||
ASMARGS_2 (arg1, arg2), "d" ((unsigned int) (arg3))
|
||||
# define LOADREGS_4(arg1, arg2, arg3, arg4) \
|
||||
LOADREGS_3 (arg1, arg2, arg3)
|
||||
# define ASMARGS_4(arg1, arg2, arg3, arg4) \
|
||||
ASMARGS_3 (arg1, arg2, arg3), "S" ((unsigned int) (arg4))
|
||||
# define LOADREGS_5(arg1, arg2, arg3, arg4, arg5) \
|
||||
LOADREGS_4 (arg1, arg2, arg3, arg4)
|
||||
# define ASMARGS_5(arg1, arg2, arg3, arg4, arg5) \
|
||||
ASMARGS_4 (arg1, arg2, arg3, arg4), "D" ((unsigned int) (arg5))
|
||||
# define LOADREGS_6(arg1, arg2, arg3, arg4, arg5, arg6) \
|
||||
register unsigned int _a6 asm ("ebp") = (unsigned int) (arg6); \
|
||||
LOADREGS_5 (arg1, arg2, arg3, arg4, arg5)
|
||||
# define ASMARGS_6(arg1, arg2, arg3, arg4, arg5, arg6) \
|
||||
ASMARGS_5 (arg1, arg2, arg3, arg4, arg5), "r" (_a6)
|
||||
#endif /* GCC 5 */
|
||||
|
||||
#define ASMFMT_0()
|
||||
#ifdef __PIC__
|
||||
# define ASMFMT_1(arg1) \
|
||||
|
||||
Loading…
Reference in New Issue
Block a user