[cfe-commits] [Windows] Use thiscall as the default calling convention for class methods

[John McCall]

On May 11, 2012, at 6:58 AM, Timur Iskhodzhanov wrote:
> Can you please review the attached patch?
> 
> In two words what it does is
> it overrides the CC_Default calling convention with
> context.getDefaultMethodCallConv()
> for all the used method definitions and calls.
> 
> What I personally don't like is that the method declarations are
> stored with CC_Default and we have to replace that with
> context.getDefaultMethodCallConv() wherever we use it.
> Unfortunately, we can't change the CC in the global declarations storage.
> I'd prefer to put the declarations into the storage with the right CC
> but not sure:
> a) if we should do it
> b) how to do it
> c) it's possible at all

I don't think modifying the AST is the right thing to do here anyway;
CC_Default is really the right way to model this.

> OTOH, it looks like there are only two places we need to alter the
> calling convention: method call and method definition :)
> So maybe I'm trying too hard to generalize...


I mostly like your patch, but I think it'd be slightly better to make the
terminal arrangeFunctionType take some sort of "function kind"
parameter (function vs. C++ instance method) and then have
ClangCallConvToLLVMCallConv consider that when mapping
CC_Default.

Also, please put this in a more generically-named test, something like
microsoft-abi-methods.cpp.  I'm sure there will be other changes that
we'll want to test for as time goes on.

Also, please test:
  - declarations of instance methods using CC_Default
  - declarations of instance methods with an explicit CC
  - declarations of static methods (to make sure they aren't thiscall)
  - direct calls to instance methods using CC_Default
  - direct calls to instance methods with an explicit CC
  - direct calls to static methods using instance call syntax

John.