Subject: Re: [PATCH v7 3/6] perf annotate: Show raw form for jump instruction with indirect target

From: Ravi Bangoria <[email-masked]>
Date: Mon, 10 Oct 2016 19:01:55 +0530

On Wednesday 05 October 2016 04:57 PM, Arnaldo Carvalho de Melo wrote:
> Em Wed, Sep 21, 2016 at 09:17:53PM +0530, Ravi Bangoria escreveu:
>> For jump instructions that does not include target address as direct
>> operand, use raw value for that. This is needed for certain powerpc
>   "use raw value" looks vague, as the example below makes is go from
> using a value (ffffffffffffca2c) to no value at all, i.e. the output
> looks backwards from what you describe, can you instead show the
> original disassembled line from objdump, which I think is what you're
> calling "raw value" in this case?

Correct, I'm showing that only -- "original disassembled line from objdump".

There is no direct operand with bctr. It uses content of register 'ctr' as target
address.

For example, objdump output:

       100b8fd8:   add    r10,r9,r10
       100b8fdc:   mtctr  r10
       100b8fe0:   bctr

> - Arnaldo
>
>> jump instructions that use target address in a register (such as bctr,
>> btar, ...).
>>
>> Before:
>>      ld     r12,32088(r12)
>>      mtctr  r12
>>   v  bctr   ffffffffffffca2c
>>      std    r2,24(r1)
>>      addis  r12,r2,-1
>>
>> After:
>>      ld     r12,32088(r12)
>>      mtctr  r12
>>   v  bctr
>>      std    r2,24(r1)
>>      addis  r12,r2,-1
>>
>> Suggested-by: Michael Ellerman <[email-masked]>
>> Signed-off-by: Ravi Bangoria <[email-masked]>
>> ---
>> Changes in v7:
>>   - Added example in description
>>
>>  tools/perf/util/annotate.c | 3 +++
>>  1 file changed, 3 insertions(+)
>>
>> diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
>> index 5aa72d9..1ccf26a 100644
>> --- a/tools/perf/util/annotate.c
>> +++ b/tools/perf/util/annotate.c
>> @@ -136,6 +136,9 @@ static int jump__parse(struct ins_operands *ops, struct map *map __maybe_unused)
>>  static int jump__scnprintf(struct ins *ins, char *bf, size_t size,
>>  			   struct ins_operands *ops)
>>  {
>> +	if (!ops->target.addr)
>> +		return ins__raw_scnprintf(ins, bf, size, ops);
>> +
>>  	return scnprintf(bf, size, "%-6.6s %" PRIx64, ins->name, ops->target.offset);
>>  }
>>  
>> -- 
>> 2.5.5