Re: [Valgrind-developers] cachegrind and vex-chase

[Josef W. <Jos...@gm...>]

Am 23.06.2016 um 13:11 schrieb Christian Borntraeger:
> On 06/20/2016 11:39 PM, Josef Weidendorfer wrote:
>> Am 20.06.2016 um 22:26 schrieb Christian Borntraeger:
>>> Simple testcase with 2 branches, both are detected:
>>>
>>> # cat test.s
>>> .globl _start
>>> _start:
>>> brasl 14,test # save next address into r14, call test
>>> svc 1 # exit system call
>>>
>>> test:
>>> br 14 # jump to r14
>>
>> What is the VEX IR both with/without chase value set to 0
>> for this nice small example?
>
> Interestingly enough for this example no different can be seen
> in the counts, but the IR differs.
>
>
>>
>> I would be interested to see the IR before and after
>> instrumentation, ie. "--trace-flags=01100000".
>
> with --vex-guest-chase-thresh=0
> ...
> default:
> ...

Hmm. Looks as expected.

It would be interesting to see the instrumentation added by cachegrind
when branch simulation is switched on.

Perhaps off-topic:

> br       %r14
>              ------ IMark(0x800000DC, 2, 0) ------
>              PUT(336) = GET:I64(304)
>              PUT(336) = GET:I64(336); exit-Return

How can the translation to VEX see that this is a Return?
Is %r14 expected to save the return address according to the ABI?


Josef