Re: [Valgrind-developers] replacing --vex-iropt-precise-memory-exns=no|yes by --vex-iropt-register-updates=minimal|atmemaccess|exact

[Philippe W. <phi...@sk...>]

On Mon, 2012-08-06 at 23:56 +0200, Josef Weidendorfer wrote:
> I assume because the guest state was not up-to-date, Valgrind's
> SEGFAULT handler was not able to detect that this was a stack underrun.
That looks to be the problem, because ensuring the stackpointer
is up to date or changing the detection logic for stack underrun fixes
all tests.
Two patches attached:
1. a patch (horrible hack) that changes the logic to detect stack
   underrun. I do not think this is the way to go. I attach it
   for the record.

Instead:
2. a complete patch with the solution to have the stack pointer
  being made up to date at memRW.
  (this looks somewhat cleaner/safer).

This second patch has run all regression tests on amd64.
All none tests have also run with --vex-iropt-register-updates=allregs-at-sb-exits.

Patch done for other archs (arm, s390, ppc32, ppc64) but not tested.

Philippe