Re: [PATCH 2/3] record-btrace, disas: omit pc prefix

[Jan Kratochvil <jan.kratochvil@redhat.com>]

On Mon, 25 Feb 2013 17:15:16 +0100, markus.t.metzger@intel.com wrote:
> From: Markus Metzger <markus.t.metzger@intel.com>
> 
> Add a disassembly flag to omit the pc prefix and use it in the "record
> instruction-history" command of record-btrace.
> 
> The pc prefix would appear multiple times in the branch trace disassembly,
> which is more confusing than helpful.

I do not see it, moreover I find the output better without this patch:

with the patch:

(gdb) record instruction-history 
warning: Recorded trace may be corrupted.
warning: Recorded trace may be corrupted.
warning: Recorded trace may be corrupted.
0x00007ffff62fe56a <_int_malloc+298>:	add    $0xa8,%rsp
0x00007ffff62fe571 <_int_malloc+305>:	mov    %r12,%rax
0x00007ffff62fe574 <_int_malloc+308>:	pop    %rbx
0x00007ffff62fe575 <_int_malloc+309>:	pop    %rbp
0x00007ffff62fe576 <_int_malloc+310>:	pop    %r12
0x00007ffff62fe578 <_int_malloc+312>:	pop    %r13
0x00007ffff62fe57a <_int_malloc+314>:	pop    %r14
0x00007ffff62fe57c <_int_malloc+316>:	pop    %r15
0x00007ffff62fe57e <_int_malloc+318>:	retq   
0x00007ffff6300ecc <__GI___libc_malloc+92>:	test   %rax,%rax
(gdb) p/x $pc
$1 = 0x7ffff6300ecc

without the patch:
(gdb) record instruction-history 
   0x00007ffff6303f51 <freehook+209>:	mov    %rax,0x0(%rbp)
   0x00007ffff6303f55 <freehook+213>:	pop    %rbx
   0x00007ffff6303f56 <freehook+214>:	pop    %rbp
   0x00007ffff6303f57 <freehook+215>:	pop    %r12
   0x00007ffff6303f59 <freehook+217>:	pop    %r13
   0x00007ffff6303f5b <freehook+219>:	pop    %r14
   0x00007ffff6303f5d <freehook+221>:	retq   
   0x00007ffff62c8921 <_IO_vfprintf_internal+257>:	mov    %r12,%rdi
   0x00007ffff62c8924 <_IO_vfprintf_internal+260>:	callq  0x7ffff62a03d0 <free@plt+64>
=> 0x00007ffff62a03d0 <free@plt+64>:	jmpq   *0x399c9a(%rip)        # 0x7ffff663a070
(gdb) p/x $pc
$1 = 0x7ffff62a03d0


It seems to me like the preference of "=> " or not "=> " is not related to
"record instruction-history".

If you do like disassemblies more without "=> " it can be made some new global
option unrelated to "record".


> 2013-02-25 Markus Metzger  <markus.t.metzger@intel.com>
> 
> 	* record-btrace.c (btrace_insn_history): Omit the pc prefix in
> 	the instruction history disassembly.
> 	* disasm.c (dump_insns): Omit the pc prefix, if requested.
> 	* disasm.h (DISASSEMBLY_OMIT_PC): New.


Thanks,
Jan