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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.
This directory contains the sources of the GNU C Library. See the file "version.h" for what release version you have. The GNU C Library is the standard system C library for all GNU systems, and is an important part of what makes up a GNU system. It provides the system API for all programs written in C and C-compatible languages such as C++ and Objective C; the runtime facilities of other programming languages use the C library to access the underlying operating system. In GNU/Linux systems, the C library works with the Linux kernel to implement the operating system behavior seen by user applications. In GNU/Hurd systems, it works with a microkernel and Hurd servers. The GNU C Library implements much of the POSIX.1 functionality in the GNU/Hurd system, using configurations i[4567]86-*-gnu. The current GNU/Hurd support requires out-of-tree patches that will eventually be incorporated into an official GNU C Library release. When working with Linux kernels, this version of the GNU C Library requires Linux kernel version 2.6.32 or later. Also note that the shared version of the libgcc_s library must be installed for the pthread library to work correctly. The GNU C Library supports these configurations for using Linux kernels: aarch64*-*-linux-gnu alpha*-*-linux-gnu arm-*-linux-gnueabi hppa-*-linux-gnu Not currently functional without patches. i[4567]86-*-linux-gnu x86_64-*-linux-gnu Can build either x86_64 or x32 ia64-*-linux-gnu m68k-*-linux-gnu microblaze*-*-linux-gnu mips-*-linux-gnu mips64-*-linux-gnu powerpc-*-linux-gnu Hardware or software floating point, BE only. powerpc64*-*-linux-gnu Big-endian and little-endian. s390-*-linux-gnu s390x-*-linux-gnu sh[34]-*-linux-gnu sparc*-*-linux-gnu sparc64*-*-linux-gnu tilegx-*-linux-gnu tilepro-*-linux-gnu If you are interested in doing a port, please contact the glibc maintainers; see http://www.gnu.org/software/libc/ for more information. See the file INSTALL to find out how to configure, build, and install the GNU C Library. You might also consider reading the WWW pages for the C library at http://www.gnu.org/software/libc/. The GNU C Library is (almost) completely documented by the Texinfo manual found in the `manual/' subdirectory. The manual is still being updated and contains some known errors and omissions; we regret that we do not have the resources to work on the manual as much as we would like. For corrections to the manual, please file a bug in the `manual' component, following the bug-reporting instructions below. Please be sure to check the manual in the current development sources to see if your problem has already been corrected. Please see http://www.gnu.org/software/libc/bugs.html for bug reporting information. We are now using the Bugzilla system to track all bug reports. This web page gives detailed information on how to report bugs properly. The GNU C Library is free software. See the file COPYING.LIB for copying conditions, and LICENSES for notices about a few contributions that require these additional notices to be distributed. License copyright years may be listed using range notation, e.g., 1996-2015, indicating that every year in the range, inclusive, is a copyrightable year that would otherwise be listed individually.