[cfe-dev] [cfe-commits] r68413 - in /cfe/trunk: include/clang/Basic/DiagnosticSemaKinds.td include/clang/Basic/TargetInfo.h lib/Basic/Targets.cpp lib/Sema/SemaDeclAttr.cpp

[Anton Korobeynikov]

Hi, Eli

> Is this documented somewhere?
Well. Yes. It defaults to gcc's REGPARM_MAX, which is 3 on x86-32 and 6
on x86-64.

>   As far as I can tell, it has no effect on the calling convention in LLVM.
That's correct. Actually regparm is among features which do not have
properly documented semantics.

So far (gcc's behaviour):
1. Hard error on non-x86 platforms
2. Ignore on x86-64 (warning is emitted with apple gcc / llvm-gcc, not
not with fsf gcc). However it's perfectly allowed to use regparm there.
3. Honour on x86-32

I decided to make clang's implementation as flexible as possible to allow theoretical
regparm(N) support for non-x86 targets, if needed.

> > +  if (NumParams.getLimitedValue(4) > S.Context.Target.getRegParmMax()) {
> > +    S.Diag(Attr.getLoc(), diag::err_attribute_regparm_invalid_number)
> > +      << S.Context.Target.getRegParmMax() << NumParamsExpr->getSourceRange();
> >     return;
> >   }
> 
> This check doesn't work correctly with getRegParmMax > 3.
Fixed, thanks

-- 
With best regards, Anton Korobeynikov.

Faculty of Mathematics & Mechanics, Saint Petersburg State University.