https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111165
--- Comment #6 from Thorsten Glaser <tg at mirbsd dot org> --- dietlibc’s strlen is a horrid SSE nightmare that doesn’t call (f)emms, but it has a switch global variable __valgrind, if setting that to 1 it uses a very traditional loop instead, and the registers before/after strlen also match (only rax has changed), so I’m at a loss. Changing the line to… sp += strlen(sp) + 1; … doesn’t make the problem go away, for some reason. Replacing it with… while (*sp++) ; … however *does* make it go away. I’ll paste a screenlog of single-stepping through the valgrind version of the code below (http://www.mirbsd.org/cvs.cgi/contrib/hosted/tg/.gdbinit?rev=HEAD has the helpful t macro): Breakpoint 1, expand (ccp=<optimized out>, wp=wp@entry=0xffffcdf0, f=f@entry=0) at eval.c:401 401 asm volatile("nop"); //401 (gdb) t => 0x40a63f <expand+1875>: nop 402 sp = cstrchr(sp, '\0') + 1; rax 0xf7ff790e 4160715022 rbx 0x0 0 rcx 0x0 0 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xffffcd5c 4294954332 rbp 0xf7ff790c 4160715020 rsp 0xffffcc90 4294954128 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x40a640 4236864 eflags 0x287 [ CF PF SF IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x40a640 <expand+1876>: mov ebx,DWORD PTR [rsp+0x48] 0x40a644 <expand+1880>: mov rdi,rbx 0x40a647 <expand+1883>: call 0x42cc7e <strlen> (gdb) t => 0x40a640 <expand+1876>: mov ebx,DWORD PTR [rsp+0x48] 0x0040a644 402 sp = cstrchr(sp, '\0') + 1; rax 0xf7ff790e 4160715022 rbx 0xf7ff790e 4160715022 rcx 0x0 0 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xffffcd5c 4294954332 rbp 0xf7ff790c 4160715020 rsp 0xffffcc90 4294954128 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x40a644 4236868 eflags 0x287 [ CF PF SF IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x40a644 <expand+1880>: mov rdi,rbx 0x40a647 <expand+1883>: call 0x42cc7e <strlen> 0x40a64c <expand+1888>: mov ecx,DWORD PTR [rsp+0x48] (gdb) t => 0x40a644 <expand+1880>: mov rdi,rbx 0x0040a647 402 sp = cstrchr(sp, '\0') + 1; rax 0xf7ff790e 4160715022 rbx 0xf7ff790e 4160715022 rcx 0x0 0 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xf7ff790e 4160715022 rbp 0xf7ff790c 4160715020 rsp 0xffffcc90 4294954128 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x40a647 4236871 eflags 0x287 [ CF PF SF IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x40a647 <expand+1883>: call 0x42cc7e <strlen> 0x40a64c <expand+1888>: mov ecx,DWORD PTR [rsp+0x48] 0x40a650 <expand+1892>: lea r12d,[rcx+rax*1+0x1] (gdb) t => 0x40a647 <expand+1883>: call 0x42cc7e <strlen> 0x0042cc7e in strlen () rax 0xf7ff790e 4160715022 rbx 0xf7ff790e 4160715022 rcx 0x0 0 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xf7ff790e 4160715022 rbp 0xf7ff790c 4160715020 rsp 0xffffcc88 4294954120 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x42cc7e 4377726 eflags 0x287 [ CF PF SF IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x42cc7e <strlen>: xor eax,eax 0x42cc80 <strlen+2>: or eax,DWORD PTR [rip+0x74ee] # 0x434174 <__valgrind> 0x42cc86 <strlen+8>: jne 0x42ccca <strlen+76> (gdb) t => 0x42cc7e <strlen>: xor eax,eax 0x0042cc80 in strlen () rax 0x0 0 rbx 0xf7ff790e 4160715022 rcx 0x0 0 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xf7ff790e 4160715022 rbp 0xf7ff790c 4160715020 rsp 0xffffcc88 4294954120 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x42cc80 4377728 eflags 0x246 [ PF ZF IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x42cc80 <strlen+2>: or eax,DWORD PTR [rip+0x74ee] # 0x434174 <__valgrind> 0x42cc86 <strlen+8>: jne 0x42ccca <strlen+76> 0x42cc88 <strlen+10>: mov rax,rdi (gdb) t => 0x42cc80 <strlen+2>: or eax,DWORD PTR [rip+0x74ee] # 0x434174 <__valgrind> 0x0042cc86 in strlen () rax 0x1 1 rbx 0xf7ff790e 4160715022 rcx 0x0 0 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xf7ff790e 4160715022 rbp 0xf7ff790c 4160715020 rsp 0xffffcc88 4294954120 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x42cc86 4377734 eflags 0x202 [ IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x42cc86 <strlen+8>: jne 0x42ccca <strlen+76> 0x42cc88 <strlen+10>: mov rax,rdi 0x42cc8b <strlen+13>: mov ecx,edi (gdb) t => 0x42cc86 <strlen+8>: jne 0x42ccca <strlen+76> 0x0042ccca in strlen () rax 0x1 1 rbx 0xf7ff790e 4160715022 rcx 0x0 0 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xf7ff790e 4160715022 rbp 0xf7ff790c 4160715020 rsp 0xffffcc88 4294954120 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x42ccca 4377802 eflags 0x202 [ IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x42ccca <strlen+76>: mov rax,rdi 0x42cccd <strlen+79>: cmp BYTE PTR [rax],0x0 0x42ccd0 <strlen+82>: je 0x42ccd7 <strlen+89> (gdb) t => 0x42ccca <strlen+76>: mov rax,rdi 0x0042cccd in strlen () rax 0xf7ff790e 4160715022 rbx 0xf7ff790e 4160715022 rcx 0x0 0 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xf7ff790e 4160715022 rbp 0xf7ff790c 4160715020 rsp 0xffffcc88 4294954120 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x42cccd 4377805 eflags 0x202 [ IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x42cccd <strlen+79>: cmp BYTE PTR [rax],0x0 0x42ccd0 <strlen+82>: je 0x42ccd7 <strlen+89> 0x42ccd2 <strlen+84>: inc rax (gdb) t => 0x42cccd <strlen+79>: cmp BYTE PTR [rax],0x0 0x0042ccd0 in strlen () rax 0xf7ff790e 4160715022 rbx 0xf7ff790e 4160715022 rcx 0x0 0 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xf7ff790e 4160715022 rbp 0xf7ff790c 4160715020 rsp 0xffffcc88 4294954120 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x42ccd0 4377808 eflags 0x206 [ PF IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x42ccd0 <strlen+82>: je 0x42ccd7 <strlen+89> 0x42ccd2 <strlen+84>: inc rax 0x42ccd5 <strlen+87>: jmp 0x42cccd <strlen+79> (gdb) t => 0x42ccd0 <strlen+82>: je 0x42ccd7 <strlen+89> 0x0042ccd2 in strlen () rax 0xf7ff790e 4160715022 rbx 0xf7ff790e 4160715022 rcx 0x0 0 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xf7ff790e 4160715022 rbp 0xf7ff790c 4160715020 rsp 0xffffcc88 4294954120 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x42ccd2 4377810 eflags 0x206 [ PF IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x42ccd2 <strlen+84>: inc rax 0x42ccd5 <strlen+87>: jmp 0x42cccd <strlen+79> 0x42ccd7 <strlen+89>: sub rax,rdi (gdb) t => 0x42ccd2 <strlen+84>: inc rax 0x0042ccd5 in strlen () rax 0xf7ff790f 4160715023 rbx 0xf7ff790e 4160715022 rcx 0x0 0 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xf7ff790e 4160715022 rbp 0xf7ff790c 4160715020 rsp 0xffffcc88 4294954120 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x42ccd5 4377813 eflags 0x206 [ PF IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x42ccd5 <strlen+87>: jmp 0x42cccd <strlen+79> 0x42ccd7 <strlen+89>: sub rax,rdi 0x42ccda <strlen+92>: ret (gdb) t => 0x42ccd5 <strlen+87>: jmp 0x42cccd <strlen+79> 0x0042cccd in strlen () rax 0xf7ff790f 4160715023 rbx 0xf7ff790e 4160715022 rcx 0x0 0 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xf7ff790e 4160715022 rbp 0xf7ff790c 4160715020 rsp 0xffffcc88 4294954120 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x42cccd 4377805 eflags 0x206 [ PF IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x42cccd <strlen+79>: cmp BYTE PTR [rax],0x0 0x42ccd0 <strlen+82>: je 0x42ccd7 <strlen+89> 0x42ccd2 <strlen+84>: inc rax (gdb) t => 0x42cccd <strlen+79>: cmp BYTE PTR [rax],0x0 0x0042ccd0 in strlen () rax 0xf7ff790f 4160715023 rbx 0xf7ff790e 4160715022 rcx 0x0 0 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xf7ff790e 4160715022 rbp 0xf7ff790c 4160715020 rsp 0xffffcc88 4294954120 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x42ccd0 4377808 eflags 0x206 [ PF IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x42ccd0 <strlen+82>: je 0x42ccd7 <strlen+89> 0x42ccd2 <strlen+84>: inc rax 0x42ccd5 <strlen+87>: jmp 0x42cccd <strlen+79> (gdb) t => 0x42ccd0 <strlen+82>: je 0x42ccd7 <strlen+89> 0x0042ccd2 in strlen () rax 0xf7ff790f 4160715023 rbx 0xf7ff790e 4160715022 rcx 0x0 0 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xf7ff790e 4160715022 rbp 0xf7ff790c 4160715020 rsp 0xffffcc88 4294954120 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x42ccd2 4377810 eflags 0x206 [ PF IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x42ccd2 <strlen+84>: inc rax 0x42ccd5 <strlen+87>: jmp 0x42cccd <strlen+79> 0x42ccd7 <strlen+89>: sub rax,rdi (gdb) t => 0x42ccd2 <strlen+84>: inc rax 0x0042ccd5 in strlen () rax 0xf7ff7910 4160715024 rbx 0xf7ff790e 4160715022 rcx 0x0 0 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xf7ff790e 4160715022 rbp 0xf7ff790c 4160715020 rsp 0xffffcc88 4294954120 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x42ccd5 4377813 eflags 0x212 [ AF IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x42ccd5 <strlen+87>: jmp 0x42cccd <strlen+79> 0x42ccd7 <strlen+89>: sub rax,rdi 0x42ccda <strlen+92>: ret (gdb) t => 0x42ccd5 <strlen+87>: jmp 0x42cccd <strlen+79> 0x0042cccd in strlen () rax 0xf7ff7910 4160715024 rbx 0xf7ff790e 4160715022 rcx 0x0 0 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xf7ff790e 4160715022 rbp 0xf7ff790c 4160715020 rsp 0xffffcc88 4294954120 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x42cccd 4377805 eflags 0x212 [ AF IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x42cccd <strlen+79>: cmp BYTE PTR [rax],0x0 0x42ccd0 <strlen+82>: je 0x42ccd7 <strlen+89> 0x42ccd2 <strlen+84>: inc rax (gdb) t => 0x42cccd <strlen+79>: cmp BYTE PTR [rax],0x0 0x0042ccd0 in strlen () rax 0xf7ff7910 4160715024 rbx 0xf7ff790e 4160715022 rcx 0x0 0 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xf7ff790e 4160715022 rbp 0xf7ff790c 4160715020 rsp 0xffffcc88 4294954120 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x42ccd0 4377808 eflags 0x202 [ IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x42ccd0 <strlen+82>: je 0x42ccd7 <strlen+89> 0x42ccd2 <strlen+84>: inc rax 0x42ccd5 <strlen+87>: jmp 0x42cccd <strlen+79> (gdb) t => 0x42ccd0 <strlen+82>: je 0x42ccd7 <strlen+89> 0x0042ccd2 in strlen () rax 0xf7ff7910 4160715024 rbx 0xf7ff790e 4160715022 rcx 0x0 0 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xf7ff790e 4160715022 rbp 0xf7ff790c 4160715020 rsp 0xffffcc88 4294954120 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x42ccd2 4377810 eflags 0x202 [ IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x42ccd2 <strlen+84>: inc rax 0x42ccd5 <strlen+87>: jmp 0x42cccd <strlen+79> 0x42ccd7 <strlen+89>: sub rax,rdi (gdb) t => 0x42ccd2 <strlen+84>: inc rax 0x0042ccd5 in strlen () rax 0xf7ff7911 4160715025 rbx 0xf7ff790e 4160715022 rcx 0x0 0 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xf7ff790e 4160715022 rbp 0xf7ff790c 4160715020 rsp 0xffffcc88 4294954120 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x42ccd5 4377813 eflags 0x206 [ PF IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x42ccd5 <strlen+87>: jmp 0x42cccd <strlen+79> 0x42ccd7 <strlen+89>: sub rax,rdi 0x42ccda <strlen+92>: ret (gdb) t => 0x42ccd5 <strlen+87>: jmp 0x42cccd <strlen+79> 0x0042cccd in strlen () rax 0xf7ff7911 4160715025 rbx 0xf7ff790e 4160715022 rcx 0x0 0 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xf7ff790e 4160715022 rbp 0xf7ff790c 4160715020 rsp 0xffffcc88 4294954120 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x42cccd 4377805 eflags 0x206 [ PF IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x42cccd <strlen+79>: cmp BYTE PTR [rax],0x0 0x42ccd0 <strlen+82>: je 0x42ccd7 <strlen+89> 0x42ccd2 <strlen+84>: inc rax (gdb) t => 0x42cccd <strlen+79>: cmp BYTE PTR [rax],0x0 0x0042ccd0 in strlen () rax 0xf7ff7911 4160715025 rbx 0xf7ff790e 4160715022 rcx 0x0 0 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xf7ff790e 4160715022 rbp 0xf7ff790c 4160715020 rsp 0xffffcc88 4294954120 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x42ccd0 4377808 eflags 0x246 [ PF ZF IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x42ccd0 <strlen+82>: je 0x42ccd7 <strlen+89> 0x42ccd2 <strlen+84>: inc rax 0x42ccd5 <strlen+87>: jmp 0x42cccd <strlen+79> (gdb) t => 0x42ccd0 <strlen+82>: je 0x42ccd7 <strlen+89> 0x0042ccd7 in strlen () rax 0xf7ff7911 4160715025 rbx 0xf7ff790e 4160715022 rcx 0x0 0 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xf7ff790e 4160715022 rbp 0xf7ff790c 4160715020 rsp 0xffffcc88 4294954120 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x42ccd7 4377815 eflags 0x246 [ PF ZF IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x42ccd7 <strlen+89>: sub rax,rdi 0x42ccda <strlen+92>: ret 0x42ccdb <strncmp>: xor ecx,ecx (gdb) t => 0x42ccd7 <strlen+89>: sub rax,rdi 0x0042ccda in strlen () rax 0x3 3 rbx 0xf7ff790e 4160715022 rcx 0x0 0 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xf7ff790e 4160715022 rbp 0xf7ff790c 4160715020 rsp 0xffffcc88 4294954120 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x42ccda 4377818 eflags 0x216 [ PF AF IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x42ccda <strlen+92>: ret 0x42ccdb <strncmp>: xor ecx,ecx 0x42ccdd <strncmp+2>: cmp edx,ecx (gdb) t => 0x42ccda <strlen+92>: ret 0x0040a64c in expand (ccp=<optimized out>, wp=wp@entry=0xffffcdf0, f=f@entry=0) at eval.c:402 402 sp = cstrchr(sp, '\0') + 1; rax 0x3 3 rbx 0xf7ff790e 4160715022 rcx 0x0 0 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xf7ff790e 4160715022 rbp 0xf7ff790c 4160715020 rsp 0xffffcc90 4294954128 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x40a64c 4236876 eflags 0x216 [ PF AF IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x40a64c <expand+1888>: mov ecx,DWORD PTR [rsp+0x48] 0x40a650 <expand+1892>: lea r12d,[rcx+rax*1+0x1] 0x40a655 <expand+1897>: nop (gdb) t => 0x40a64c <expand+1888>: mov ecx,DWORD PTR [rsp+0x48] 0x0040a650 402 sp = cstrchr(sp, '\0') + 1; rax 0x3 3 rbx 0xf7ff790e 4160715022 rcx 0xf7ff790e 4160715022 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xf7ff790e 4160715022 rbp 0xf7ff790c 4160715020 rsp 0xffffcc90 4294954128 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0x2 2 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x40a650 4236880 eflags 0x216 [ PF AF IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x40a650 <expand+1892>: lea r12d,[rcx+rax*1+0x1] 0x40a655 <expand+1897>: nop 0x40a656 <expand+1898>: movzx ecx,BYTE PTR [ebp+0x2] (gdb) t => 0x40a650 <expand+1892>: lea r12d,[rcx+rax*1+0x1] 405 asm volatile("nop"); //403 rax 0x3 3 rbx 0xf7ff790e 4160715022 rcx 0xf7ff790e 4160715022 rdx 0xffffff81 4294967169 rsi 0x98 152 rdi 0xf7ff790e 4160715022 rbp 0xf7ff790c 4160715020 rsp 0xffffcc90 4294954128 r8 0xa0 160 r9 0x3 3 r10 0x0 0 r11 0x206 518 r12 0xf7ff7912 4160715026 r13 0xffffd1b4 4294955444 r14 0xf7ff510c 4160704780 r15 0x0 0 rip 0x40a655 4236885 eflags 0x216 [ PF AF IF ] cs 0x33 51 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x0 0 => 0x40a655 <expand+1897>: nop 0x40a656 <expand+1898>: movzx ecx,BYTE PTR [ebp+0x2] 0x40a65b <expand+1903>: test ecx,ecx
