Re: [Valgrind-developers] make valgrind.h safe for x32

[Tom H. <to...@co...>]

On 12/08/15 07:09, Tom Hughes wrote:
> On 12/08/15 03:25, Bart Van Assche wrote:
>
>> Ah, right, your purpose is that the Valgrind macros do not emit any
>> client requests on x32. Unless this is very clearly documented that
>> might be a confusing outcome for x32 users ... Maybe these users expect
>> that if they build a program for x32 and analyze it with Valgrind that
>> these macros just work ?
>
> Well how would they analyse such a program with valgrind? The launcher
> would reject an x32 binary on the grounds that it isn't supported...

On closer inspection it looks like the laucher won't actually refuse but 
I don't think it will work either.

Basically select_platform will fail, because EI_CLASS will be ELFCLASS32 
but e_machine will be EM_X86_64 which is not a combination we recognise. 
So we will fallback to using amd64-linux as the default platform.

But that will of course use a 64 bit address space, so it's unlikely 
that an x32 binary will get very far.

In fact I think once the tool tries to load the ELF readelf() in 
m_ume/elf.c will just abort because the class will be wrong.

Tom

-- 
Tom Hughes (to...@co...)
http://compton.nu/