[cfe-commits] r109960 - in /cfe/trunk: lib/CodeGen/CGObjCMac.cpp test/CodeGenObjC/exceptions.m test/CodeGenObjC/synchronized.m

[Chris Lattner]

On Jul 31, 2010, at 5:47 PM, John McCall wrote:

> On Jul 31, 2010, at 5:38 PM, Chris Lattner wrote:
>> Inline assembly?  Yuck.  I thought that [llvm-]gcc just marked tons of locals as volatile?
> 
> It does, but then it ends up with all these horrible liveness problems it has to work around.
> It's also done in a really intrusive way in the type-checker.
> 
> It looked like my only bet for avoiding that without intrusive changes to IR gen — i.e.
> some way of saying "okay, these things are volatile even if the AST says they aren't" —
> was to go back over the function at the end and mark every single load and store
> as volatile.  I didn't really consider that acceptable.

I agree that the gcc implementation of this is terrible, but the end result (load/store operations being marked volatile) isn't so terrible.   What's wrong with a pass after IRGen that marks all accesses to allocas volatile?

-Chris