[cfe-commits] [PATCH/RFC] Extend TBAA to handle OpenCL address spaces

[Justin Holewinski]

On Fri, Oct 14, 2011 at 11:57 AM, Peter Collingbourne <peter at pcc.me.uk>wrote:

> On Fri, Oct 14, 2011 at 02:01:46PM -0400, Justin Holewinski wrote:
> > -llvm::MDNode *CodeGenTBAA::getChar() {
> > +llvm::MDNode *CodeGenTBAA::getChar(Qualifiers& Quals) {
>
> Qualifiers is a lightweight type, and should be passed by value.
>
> >  llvm::MDNode *
> > -CodeGenTBAA::getTBAAInfo(QualType QTy) {
> > +CodeGenTBAA::getTBAAInfo(QualType QTy, Qualifiers *Override) {
>
> I think it's best if you split getTBAAInfo into two functions:
> one which takes a QualType and the other which takes a canonical
> SplitQualType.  The former would check for the may_alias attribute,
> while the latter would contain the rest of the code (and be called
> recursively for the unsigned->signed mapping).  To call the latter from
> the former, you can obtain a SplitQualType using the QualType::split
> function on the canonical type.
>
> > @@ -42,10 +43,12 @@
> >    MangleContext &MContext;
> >
> >    /// MetadataCache - This maps clang::Types to llvm::MDNodes describing
> them.
> > -  llvm::DenseMap<const Type *, llvm::MDNode *> MetadataCache;
> > +  llvm::DenseMap<std::pair<const Type *, unsigned>, llvm::MDNode *>
> > +    MetadataCache;
> >
> >    llvm::MDNode *Root;
> > -  llvm::MDNode *Char;
> > +
> > +  llvm::DenseMap<unsigned, llvm::MDNode *> CharCache;
>
> A cheaper way of defining MetadataCache and CharCache would be
> as arrays of (respectively) DenseMaps or MDNode pointers of size
> LangAS::Count+1.  You can then define a function which defines
> a mapping from a Qualifiers object to an integer between 0 and
> LangAS::Count (the return value of which conceptually represents a
> set of aliasing qualifiers) which would be used to index the arrays.
>

Thanks for the comments.  Are you okay with the general approach?


>
> Thanks,
> --
> Peter
>



-- 

Thanks,

Justin Holewinski
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