On 2013.12.02 at 16:05 +0100, Markus Trippelsdorf wrote:
> On 2013.12.02 at 15:15 +0100, Antoine Pelisse wrote:
> > Would that mean that gcc is doing some steps in the wrong order ? That
> > is setting xecfg.hunk_func and then emptying the structure ? I've
> > already had a similar bug, but that's very unfortunate.
>
> Yes. I think this might be the case:
>
> (gdb) disass
> Dump of assembler code for function diff_hunks:
> 0x0000000000410460 <+0>: sub $0x58,%rsp
> 0x0000000000410464 <+4>: xor %eax,%eax
> 0x0000000000410466 <+6>: mov %eax,%r9d
> 0x0000000000410469 <+9>: add $0x20,%eax
> 0x000000000041046c <+12>: cmp $0x20,%eax
> 0x000000000041046f <+15>: movq $0x0,0x20(%rsp,%r9,1)
> 0x0000000000410478 <+24>: movq $0x0,0x28(%rsp,%r9,1)
> 0x0000000000410481 <+33>: movq $0x0,0x30(%rsp,%r9,1)
> 0x000000000041048a <+42>: movq $0x0,0x38(%rsp,%r9,1)
> 0x0000000000410493 <+51>: jb 0x410466 <diff_hunks+6>
> 0x0000000000410495 <+53>: lea 0x20(%rsp),%r10
> 0x000000000041049a <+58>: mov %rdx,0x20(%rsp)
> 0x000000000041049f <+63>: mov %rcx,0x48(%rsp)
> 0x00000000004104a4 <+68>: add %r10,%rax
> 0x00000000004104a7 <+71>: mov %r8,0x10(%rsp)
> 0x00000000004104ac <+76>: mov %rsp,%rdx
> 0x00000000004104af <+79>: movq $0x0,(%rax)
> 0x00000000004104b6 <+86>: movq $0x0,0x8(%rax)
> 0x00000000004104be <+94>: lea 0x10(%rsp),%r8
> 0x00000000004104c3 <+99>: movslq 0x171882(%rip),%rax # 0x581d4c <xdl_opts>
> 0x00000000004104ca <+106>: mov %r10,%rcx
> 0x00000000004104cd <+109>: movq $0x0,0x18(%rsp)
> 0x00000000004104d6 <+118>: mov %rax,(%rsp)
> 0x00000000004104da <+122>: callq 0x50aee0 <xdi_diff>
> => 0x00000000004104df <+127>: add $0x58,%rsp
> 0x00000000004104e3 <+131>: retq
> End of assembler dump.
Should be fixed in gcc soon. For the curious, here is the assembler diff
(bad vs. good):
.type diff_hunks, @function
diff_hunks:
.LFB104:
.cfi_startproc
subq $88, %rsp
.cfi_def_cfa_offset 96
xorl %eax, %eax
.L31:
movl %eax, %r9d
addl $32, %eax
cmpl $32, %eax
movq $0, 32(%rsp,%r9)
movq $0, 40(%rsp,%r9)
movq $0, 48(%rsp,%r9)
movq $0, 56(%rsp,%r9)
jb .L31
leaq 32(%rsp), %r10
movq %rdx, 32(%rsp)
- movq %rcx, 72(%rsp)
- addq %r10, %rax
movq %r8, 16(%rsp)
+ addq %r10, %rax
+ leaq 16(%rsp), %r8
movq %rsp, %rdx
- movq $0, (%rax)
movq $0, 8(%rax)
- leaq 16(%rsp), %r8
+ movq $0, (%rax)
movslq xdl_opts(%rip), %rax
+ movq %rcx, 72(%rsp)
movq %r10, %rcx
movq $0, 24(%rsp)
movq %rax, (%rsp)
call xdi_diff
addq $88, %rsp
.cfi_def_cfa_offset 8
--
Markus
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