[PATCH, RFC] Fix PR16456 (make bool a context-sensitive keyword in Altivec mode)

[Bill Schmidt]

On Wed, 2013-07-03 at 15:16 -0500, Bill Schmidt wrote:
> On Wed, 2013-07-03 at 13:08 -0700, Richard Smith wrote:
> > On Wed, Jul 3, 2013 at 12:32 PM, Bill Schmidt
> > <wschmidt at linux.vnet.ibm.com> wrote:
> > > "bool" should be a context-sensitive keyword in Altivec mode.
> > >
> > > PR16456 reported that Clang implements a hybrid between AltiVec's
> > > "Keyword and Predefine Method" and its "Context Sensitive Keyword
> > > Method," where "bool" is always a keyword, but "vector" and "pixel"
> > > are context-sensitive keywords.  This isn't permitted by the AltiVec
> > > spec.  For consistency with gcc, this patch implements the Context
> > > Sensitive Keyword Method for bool, and stops treating true and false
> > > as keywords in Altivec mode.
> > >
> > > The patch removes KEYALTIVEC as a trigger for defining these keywords
> > > in include/clang/Basic/TokenKinds.def, and adds logic for "vector
> > > bool" that mirrors the existing logic for "vector pixel."  The test
> > > case is taken from the bug report.
> > >
> > > I know very little about the front end, so I would appreciate some
> > > review prior to committing the patch.  Thanks!
> > 
> > The patch contains windows line endings. Please make sure you don't
> > commit with windows line endings.
> 
> That's...odd.  Evolution must have messed it up.  I work only in Linux.
> 
> > 
> > --- include/clang/Parse/Parser.h	(revision 185433)
> > +++ include/clang/Parse/Parser.h	(working copy)
> > @@ -531,7 +532,8 @@ class Parser : public CodeCompletionHandler {
> >                         bool &isInvalid) {
> >      if (!getLangOpts().AltiVec ||
> >          (Tok.getIdentifierInfo() != Ident_vector &&
> > -         Tok.getIdentifierInfo() != Ident_pixel))
> > +         Tok.getIdentifierInfo() != Ident_pixel &&
> > +         Tok.getIdentifierInfo() != Ident_bool))
> > 
> > This looks wrong:
> > 
> >   bool x;
> > 
> > is not valid with -faltivec; bool is only a keyword after 'vector'. We
> > shouldn't be handling 'pixel' here either, FWIW. Per the AltiVec spec,
> > 2.2.2:
> > 
> > "Since vector must be first among the type specifiers, it can be
> > recognized as a type
> > specifier when a type identifier is being scanned. The new uses of pixel
> > and bool occur
> > after vector has been recognized. In all other contexts, vector,
> > pixel, and bool are not
> > reserved."
> 
> OK, I'll remove handling for both and re-test.
> 
> > 
> > 
> > --- lib/Parse/ParseDecl.cpp	(revision 185433)
> > +++ lib/Parse/ParseDecl.cpp	(working copy)
> > @@ -5623,6 +5631,10 @@ bool Parser::TryAltiVecTokenOutOfLine(DeclSpec &DS
> >               DS.isTypeAltiVecVector()) {
> >      isInvalid = DS.SetTypeAltiVecPixel(true, Loc, PrevSpec, DiagID);
> >      return true;
> > +  } else if ((Tok.getIdentifierInfo() == Ident_bool) &&
> > +             DS.isTypeAltiVecVector()) {
> > +    isInvalid = DS.SetTypeAltiVecBool(true, Loc, PrevSpec, DiagID);
> > +    return true;
> >    }
> >    return false;
> >  }
> > 
> > Likewise, this looks wrong, as does the handling of 'pixel' before it.
> > 
> 
> OK, likewise with the removal/re-test. ;)

Richard, if I remove either of these chunks, clang fails to recognize
"vector bool" and "vector pixel" as legitimate constructs.

Regarding the second chunk, I believe the test DS.isTypeAltiVecVector()
indicates that we've already recognized that we're inside a "vector"
decl when processing "pixel" or "bool".  And without the first chunk we
never get to check things for the second.

Thanks,
Bill

> 
> Thanks!  
> Bill
> 
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