看一个coredump:
代码语言：javascript复制Program terminated with signal 11, Segmentation fault.
#0 0x0090bb06 in __strlen_sse2_bsf () from /lib/libc.so.6
Missing separate debuginfos, use: debuginfo-install glibc-2.12-1.149.el6_6.5.i686 libgcc-4.4.7-11.el6.i686 libstdc -4.4.7-11.el6.i686
(gdb) bt
#0 0x0090bb06 in __strlen_sse2_bsf () from /lib/libc.so.6
#1 0x00cd88b3 in std::basic_string<char, std::char_traits<char>, std::allocator<char> >::operator=(char const*) () from /usr/lib/libstdc .so.6
#2 0x080485b7 in main ()看一下__strlen_sse2_bsf的汇编:
代码语言：javascript复制(gdb) frame 0
#0 0x0090bb06 in __strlen_sse2_bsf () from /lib/libc.so.6
(gdb) disassemble
Dump of assembler code for function __strlen_sse2_bsf:
0x0090baf0 < 0>: push %esi
0x0090baf1 < 1>: push �i
0x0090baf2 < 2>: mov 0xc(%esp),�i
0x0090baf6 < 6>: xor �x,�x
0x0090baf8 < 8>: mov �i,�x
0x0090bafa < 10>: and $0x3f,�x
0x0090bafd < 13>: pxor %xmm0,%xmm0
0x0090bb01 < 17>: cmp $0x30,�x
0x0090bb04 < 20>: ja 0x90bb1d <__strlen_sse2_bsf 45>
=> 0x0090bb06 < 22>: movdqu (�i),%xmm1
0x0090bb0a < 26>: pcmpeqb %xmm1,%xmm0
0x0090bb0e < 30>: pmovmskb %xmm0,�x
0x0090bb12 < 34>: test �x,�x
0x0090bb14 < 36>: jne 0x90bb89 <__strlen_sse2_bsf 153>
0x0090bb16 < 38>: mov �i,�x
0x0090bb18 < 40>: and $0xfffffff0,�x
0x0090bb1b < 43>: jmp 0x90bb37 <__strlen_sse2_bsf 71>
0x0090bb1d < 45>: mov �i,�x看一下寄存器的值:
代码语言：javascript复制(gdb) i r edi
edi 0x0 0
(gdb) i r ecx
ecx 0x0 0
