2016-10-05 11:27:12

by Arnaldo Carvalho de Melo

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

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?

- 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 protected]>
> Signed-off-by: Ravi Bangoria <[email protected]>
> ---
> 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

2016-10-10 13:33:08

by Ravi Bangoria

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

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 protected]>
>> Signed-off-by: Ravi Bangoria <[email protected]>
>> ---
>> 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