[cfe-commits] r166731 - /cfe/trunk/test/CodeGenCXX/catch-undef-behavior.cpp

[Chris Lattner]

On Oct 25, 2012, at 11:59 PM, Richard Smith <richard at metafoo.co.uk> wrote:

> On Thu, Oct 25, 2012 at 9:48 PM, Chris Lattner <clattner at apple.com> wrote:
>> 
>> On Oct 25, 2012, at 3:27 PM, Richard Smith <richard-llvm at metafoo.co.uk> wrote:
>> 
>>> Author: rsmith
>>> Date: Thu Oct 25 17:27:30 2012
>>> New Revision: 166731
>>> 
>>> URL: http://llvm.org/viewvc/llvm-project?rev=166731&view=rev
>>> Log:
>>> LLVM's hashing routines produce a size_t, and thus generate different values for 32- and 64-bit host compilers. This really needs to be fixed -- the IR generated should not depend on the host -- but this change will get the bots green again. Proper fix to follow.
>> 
>> Codegen shouldn't depend on specific hash values - iteration over densemap (and friends) is considered nondeterministic.  What are you seeing?
> 
> Sorry for the imprecision! This sanitizer pass generates uniquish
> numbers for classes by hashing their mangled names, which are then
> emitted into the IR and used to cache the results of an 'is this type
> derived from that type?' query. LLVM's hashing functions produce
> different results on 32- and 64-bit platforms due to their use of
> size_t, resulting in different IR generated in the two different
> cases. The fix here is just to move away from using these hashing
> routines, onto something which produces a more stable unique class ID.

Ok, makes sense!

-Chris