Re: [Valgrind-users] Unhandled instruction in libm

[Florian K. <br...@ac...>]

On 08/06/2013 08:02 PM, Kingsley, James Leonard wrote:
> Attempting to use valgrind on my system gives me an 'unrecognised instruction' error.  I am reasonably sure that it's a valgrind issue
> 

Yes, it is.

> vex amd64->IR: unhandled instruction bytes: 0xC4 0xE3 0xD9 0x6B 0x3D 0x4E 0x19 0x6
> vex amd64->IR:   REX=0 REX.W=1 REX.R=0 REX.X=0 REX.B=0
> vex amd64->IR:   VEX=1 VEX.L=0 VEX.nVVVV=0x4 ESC=0F3A
> vex amd64->IR:   PFX.66=1 PFX.F2=0 PFX.F3=0
> ==25013== valgrind: Unrecognised instruction at address 0x4c37a00.
> ==25013==    at 0x4C37A00: __ieee754_log_sse2 (in /lib64/libm-2.15.so)

This function has caused trouble before. See
https://bugs.kde.org/show_bug.cgi?id=320965

> 
> Any suggestions on fixing this?  

No work-around really, other than recompiling libm with a suitable set
of compiler flags (I would not know what those are).
If you're brave and have some time, you might be interested in adding
support for this instruction to valgrind. The code to look at would be
in <valgrind>/VEX/priv/guest_amd64_toIR.c, function disInstr_AMD64_WRK
and underneath.

   Florian