[PATCH] Use dereferencable attribute in Clang for C++ references

[Richard Smith]

My comments were the same as Aaron's =)

Other than that, LGTM.

On Fri, Jul 11, 2014 at 9:49 AM, Aaron Ballman <aaron at aaronballman.com>
wrote:

> On Fri, Jul 11, 2014 at 1:50 AM, hfinkel at anl.gov <hfinkel at anl.gov> wrote:
> > Fixed up the remaining regression tests (now all pass), and added a new
> test for dereferenceable/nonnull on non-addrspace(0) references.
> >
> > http://reviews.llvm.org/D4450
> >
> > Files:
> >   lib/CodeGen/CGCall.cpp
> >   test/CXX/except/except.spec/p14-ir.cpp
> >   test/CodeGenCXX/address-space-ref.cpp
> >   test/CodeGenCXX/blocks-cxx11.cpp
> >   test/CodeGenCXX/blocks.cpp
> >   test/CodeGenCXX/catch-undef-behavior.cpp
> >   test/CodeGenCXX/conditional-gnu-ext.cpp
> >   test/CodeGenCXX/const-init-cxx11.cpp
> >   test/CodeGenCXX/constructor-direct-call.cpp
> >   test/CodeGenCXX/constructor-init.cpp
> >   test/CodeGenCXX/convert-to-fptr.cpp
> >   test/CodeGenCXX/copy-assign-synthesis-1.cpp
> >   test/CodeGenCXX/copy-constructor-elim-2.cpp
> >   test/CodeGenCXX/copy-constructor-synthesis-2.cpp
> >   test/CodeGenCXX/copy-constructor-synthesis.cpp
> >   test/CodeGenCXX/cxx11-initializer-aggregate.cpp
> >   test/CodeGenCXX/cxx11-thread-local-reference.cpp
> >   test/CodeGenCXX/decl-ref-init.cpp
> >   test/CodeGenCXX/default-arg-temps.cpp
> >   test/CodeGenCXX/derived-to-base-conv.cpp
> >   test/CodeGenCXX/derived-to-virtual-base-class-calls-final.cpp
> >   test/CodeGenCXX/dllexport-members.cpp
> >   test/CodeGenCXX/dllexport.cpp
> >   test/CodeGenCXX/dllimport-members.cpp
> >   test/CodeGenCXX/dllimport.cpp
> >   test/CodeGenCXX/eh.cpp
> >   test/CodeGenCXX/empty-nontrivially-copyable.cpp
> >   test/CodeGenCXX/exceptions.cpp
> >   test/CodeGenCXX/fastcall.cpp
> >   test/CodeGenCXX/goto.cpp
> >   test/CodeGenCXX/implicit-copy-assign-operator.cpp
> >   test/CodeGenCXX/implicit-copy-constructor.cpp
> >   test/CodeGenCXX/mangle-lambdas.cpp
> >   test/CodeGenCXX/mangle.cpp
> >   test/CodeGenCXX/microsoft-abi-sret-and-byval.cpp
> >   test/CodeGenCXX/microsoft-abi-static-initializers.cpp
> >   test/CodeGenCXX/nrvo.cpp
> >   test/CodeGenCXX/pod-member-memcpys.cpp
> >   test/CodeGenCXX/pointers-to-data-members.cpp
> >   test/CodeGenCXX/reference-cast.cpp
> >   test/CodeGenCXX/rvalue-references.cpp
> >   test/CodeGenCXX/temporaries.cpp
> >   test/CodeGenCXX/throw-expressions.cpp
> >   test/CodeGenCXX/volatile.cpp
> >   test/CodeGenObjC/return-objc-object.mm
> >   test/CodeGenObjCXX/arc-blocks.mm
> >   test/CodeGenObjCXX/arc-move.mm
> >   test/CodeGenObjCXX/arc-special-member-functions.mm
> >   test/CodeGenObjCXX/implicit-copy-assign-operator.mm
> >   test/CodeGenObjCXX/implicit-copy-constructor.mm
> >   test/CodeGenObjCXX/lvalue-reference-getter.mm
> >   test/CodeGenObjCXX/message-reference.mm
> >   test/CodeGenObjCXX/property-dot-reference.mm
> >   test/CodeGenObjCXX/property-lvalue-capture.mm
> >   test/CodeGenObjCXX/property-object-reference-2.mm
> >   test/CodeGenObjCXX/property-objects.mm
> >   test/CodeGenObjCXX/property-reference.mm
> >   test/Modules/templates.mm
>
> I have no real comments on whether this is the correct approach or
> not, but I do have a small style nit:
>
> > Index: lib/CodeGen/CGCall.cpp
> > ===================================================================
> > --- lib/CodeGen/CGCall.cpp
> > +++ lib/CodeGen/CGCall.cpp
> > @@ -1200,8 +1200,14 @@
> >      llvm_unreachable("Invalid ABI kind for return argument");
> >    }
> >
> > -  if (RetTy->isReferenceType())
> > -    RetAttrs.addAttribute(llvm::Attribute::NonNull);
> > +  if (RetTy->isReferenceType()) {
> > +    QualType PTy = RetTy->getAs<ReferenceType>()->getPointeeType();
>
> if (const auto *RefTy = RetTy->getAs<ReferenceType>()) {
>   QualType Pty = RefTy->getPointeeType();
>   ...
>
> > +    if (!PTy->isIncompleteType() && PTy->isConstantSizeType())
> > +
>  RetAttrs.addDereferenceableAttr(getContext().getTypeSizeInChars(PTy)
> > +                                        .getQuantity());
> > +    else if (getContext().getTargetAddressSpace(PTy) == 0)
> > +      RetAttrs.addAttribute(llvm::Attribute::NonNull);
> > +  }
> >
> >    if (RetAttrs.hasAttributes())
> >      PAL.push_back(llvm::
> > @@ -1291,8 +1297,14 @@
> >      }
> >      }
> >
> > -    if (ParamType->isReferenceType())
> > -      Attrs.addAttribute(llvm::Attribute::NonNull);
> > +    if (ParamType->isReferenceType()) {
> > +      QualType PTy =
> ParamType->getAs<ReferenceType>()->getPointeeType();
>
> Same here as above.
>
> > +      if (!PTy->isIncompleteType() && PTy->isConstantSizeType())
> > +
>  Attrs.addDereferenceableAttr(getContext().getTypeSizeInChars(PTy)
> > +                                       .getQuantity());
> > +      else if (getContext().getTargetAddressSpace(PTy) == 0)
> > +        Attrs.addAttribute(llvm::Attribute::NonNull);
> > +    }
>
> ~Aaron
>
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