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| author | H.J. Lu <hjl.tools@gmail.com> | 2016-06-09 04:43:16 -0700 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2016-06-09 04:43:31 -0700 |
| commit | ac187dc4abde9ca6504c646106e2a7f7b2806262 (patch) | |
| tree | 6399e3373227afacaa5575f18f9304ad9ddd7a86 /COPYING | |
| parent | 75437079e4c5a7416052940ca641a41ddbf6f5fd (diff) | |
| download | glibc-ac187dc4abde9ca6504c646106e2a7f7b2806262.tar.gz glibc-ac187dc4abde9ca6504c646106e2a7f7b2806262.tar.xz glibc-ac187dc4abde9ca6504c646106e2a7f7b2806262.zip | |
Always indirect branch to __libc_start_main via GOT
Since __libc_start_main in libc.so is called very early, lazy binding isn't relevant. Always call __libc_start_main with indirect branch via GOT to avoid extra branch to PLT slot. In case of static executable, ld in binutils 2.26 or above can convert indirect branch into direct branch: 0000000000400a80 <_start>: 400a80: 31 ed xor %ebp,%ebp 400a82: 49 89 d1 mov %rdx,%r9 400a85: 5e pop %rsi 400a86: 48 89 e2 mov %rsp,%rdx 400a89: 48 83 e4 f0 and $0xfffffffffffffff0,%rsp 400a8d: 50 push %rax 400a8e: 54 push %rsp 400a8f: 49 c7 c0 20 1b 40 00 mov $0x401b20,%r8 400a96: 48 c7 c1 90 1a 40 00 mov $0x401a90,%rcx 400a9d: 48 c7 c7 c0 03 40 00 mov $0x4003c0,%rdi 400aa4: 67 e8 96 09 00 00 addr32 callq 401440 <__libc_start_main> 400aaa: f4 hlt * sysdeps/x86_64/start.S (_start): Always indirect branch to __libc_start_main via GOT.
Diffstat (limited to 'COPYING')
0 files changed, 0 insertions, 0 deletions