mirror of git://sourceware.org/git/glibc.git
83c01ab32b
This patch removes i386 assembly implementation for mmap, mmap64,
semtimeop now that i386 have 6 argument syscall support from C code
and GCC 5 can inline syscalls with 6 arguments. We also compile mmap.c,
mmap64.c and semtimedop.c with -fomit-frame-pointer since %ebp may be
used to pass the 6th argument to syscall.
Fo sysdeps/unix/sysv/linux/i386/mmap.c, with -O2 -march=i686
-mtune=generic, GCC 5.2 now generates:
<__mmap>:
0: sub $0x10,%esp
3: mov 0x28(%esp),%eax
7: mov %ebx,(%esp)
a: mov 0x18(%esp),%ecx
e: mov %esi,0x4(%esp)
12: mov 0x14(%esp),%ebx
16: mov %edi,0x8(%esp)
1a: mov 0x1c(%esp),%edx
1e: test $0xfff,%eax
23: mov 0x20(%esp),%esi
27: mov %ebp,0xc(%esp)
2b: mov 0x24(%esp),%edi
2f: jne 60 <__mmap+0x60>
31: shr $0xc,%eax
34: mov %eax,%ebp
36: mov $0xc0,%eax
3b: call *%gs:0x10
42: cmp $0xfffff000,%eax
47: ja 65 <__mmap+0x65>
49: mov (%esp),%ebx
4c: mov 0x4(%esp),%esi
50: mov 0x8(%esp),%edi
54: mov 0xc(%esp),%ebp
58: add $0x10,%esp
5b: ret
5c: lea 0x0(%esi,%eiz,1),%esi
60: mov $0xffffffea,%eax
65: mov (%esp),%ebx
68: mov 0x4(%esp),%esi
6c: mov 0x8(%esp),%edi
70: mov 0xc(%esp),%ebp
74: add $0x10,%esp
77: jmp 78 <__mmap+0x78>
vs sysdeps/unix/sysv/linux/i386/mmap.S:
<__mmap>:
0: push %ebp
1: push %ebx
2: push %esi
3: push %edi
4: mov 0x14(%esp),%ebx
8: mov 0x18(%esp),%ecx
c: mov 0x1c(%esp),%edx
10: mov 0x20(%esp),%esi
14: mov 0x24(%esp),%edi
18: mov 0x28(%esp),%ebp
1c: test $0xfff,%ebp
22: mov $0xffffffea,%eax
27: jne 38 <__mmap+0x38>
29: shr $0xc,%ebp
2c: mov $0xc0,%eax
31: call *%gs:0x10
38: pop %edi
39: pop %esi
3a: pop %ebx
3b: pop %ebp
3c: cmp $0xfffff000,%eax
41: ja 44 <__mmap+0x44>
43: ret
44: call 45 <__mmap+0x45> 45: R_386_PC32 __x86.get_pc_thunk.cx
49: add $0x2,%ecx 4b: R_386_GOTPC _GLOBAL_OFFSET_TABLE_
4f: mov 0x0(%ecx),%ecx 51: R_386_TLS_GOTIE __libc_errno
55: neg %eax
57: mov %eax,%gs:(%ecx)
5a: or $0xffffffff,%eax
5d: ret
The C version has:
3: mov 0x28(%esp),%eax
...
1e: test $0xfff,%eax
...
31: sar $0xc,%eax
34: mov %eax,%ebp
is due to missing $ebx register constraint for inline asm. We have
to use "r" constraint with
register unsigned int _a6 asm ("ebp") = (unsigned int) (arg6);
and compiler chose %eax for offset (arg6) in
if (offset & (MMAP_PAGE_UNIT - 1))
* sysdeps/unix/sysv/linux/i386/Makefile (CFLAGS-epoll_pwait.c):
Add -fomit-frame-pointer.
(CFLAGS-mmap.c): Likewise.
(CFLAGS-mmap64.c): Likewise.
(CFLAGS-semtimedop.c): Likewise.
* sysdeps/unix/sysv/linux/i386/mmap.c: New file.
* sysdeps/unix/sysv/linux/i386/mmap.S: Remove file.
* sysdeps/unix/sysv/linux/i386/mmap64.S: Likewise.
* sysdeps/unix/sysv/linux/i386/semtimedop.S: Likewise.
|
||
|---|---|---|
| .. | ||
| i686 | ||
| i786 | ||
| Implies | ||
| Makefile | ||
| Versions | ||
| ____longjmp_chk.S | ||
| _exit.S | ||
| alphasort64.c | ||
| arch-fork.h | ||
| brk.c | ||
| c++-types.data | ||
| clone.S | ||
| configure | ||
| configure.ac | ||
| dl-librecon.h | ||
| dl-procinfo.h | ||
| dl-sysdep.h | ||
| epoll_pwait.S | ||
| fcntl.c | ||
| fxstat.c | ||
| fxstatat.c | ||
| get_clockfreq.c | ||
| getcontext.S | ||
| getdents64.c | ||
| getmsg.c | ||
| getrlimit64.c | ||
| gettimeofday.c | ||
| glob64.c | ||
| init-first.c | ||
| kernel-features.h | ||
| ld.abilist | ||
| ldconfig.h | ||
| libBrokenLocale.abilist | ||
| libanl.abilist | ||
| libc-do-syscall.S | ||
| libc-lowlevellock.S | ||
| libc.abilist | ||
| libcrypt.abilist | ||
| libdl.abilist | ||
| libm.abilist | ||
| libnsl.abilist | ||
| libpthread.abilist | ||
| libresolv.abilist | ||
| librt.abilist | ||
| libthread_db.abilist | ||
| libutil.abilist | ||
| lll_timedlock_wait.c | ||
| lll_timedwait_tid.c | ||
| localplt.data | ||
| lockf64.c | ||
| lowlevellock.S | ||
| lowlevellock.h | ||
| lowlevelrobustlock.S | ||
| lxstat.c | ||
| makecontext.S | ||
| mmap.c | ||
| olddirent.h | ||
| oldgetrlimit64.c | ||
| posix_fadvise64.S | ||
| profil-counter.h | ||
| pthread_barrier_wait.S | ||
| pthread_cond_broadcast.S | ||
| pthread_cond_signal.S | ||
| pthread_cond_timedwait.S | ||
| pthread_cond_wait.S | ||
| putmsg.c | ||
| readdir64.c | ||
| readdir64_r.c | ||
| readelflib.c | ||
| register-dump.h | ||
| scandir64.c | ||
| setcontext.S | ||
| setegid.c | ||
| seteuid.c | ||
| setgid.c | ||
| setgroups.c | ||
| setregid.c | ||
| setresgid.c | ||
| setresuid.c | ||
| setreuid.c | ||
| setuid.c | ||
| shlib-versions | ||
| sigaction.c | ||
| sigcontextinfo.h | ||
| smp.h | ||
| swapcontext.S | ||
| syscall.S | ||
| syscalls.list | ||
| sysdep-cancel.h | ||
| sysdep.c | ||
| sysdep.h | ||
| time.c | ||
| ucontext_i.sym | ||
| versionsort64.c | ||
| vfork.S | ||
| xstat.c | ||