aaron.ballman added inline comments.
================
Comment at: clang/tools/libclang/CXType.cpp:132
+ if (!(TU->ParsingOptions & CXTranslationUnit_IncludeAttributedTypes) &&
+ ATT->getAttrKind() != attr::AddressSpace) {
return MakeCXType(ATT->getModifiedType(), TU);
----------------
leonardchan wrote:
> leonardchan wrote:
> > aaron.ballman wrote:
> > > leonardchan wrote:
> > > > aaron.ballman wrote:
> > > > > leonardchan wrote:
> > > > > > aaron.ballman wrote:
> > > > > > > leonardchan wrote:
> > > > > > > > aaron.ballman wrote:
> > > > > > > > > leonardchan wrote:
> > > > > > > > > > aaron.ballman wrote:
> > > > > > > > > > > This change seems surprising -- if the parsing options
> > > > > > > > > > > say the caller does not want attributed types, why are we
> > > > > > > > > > > returning one anyway for address space?
> > > > > > > > > > This has to do with ensuring `clang_getAddressSpace` still
> > > > > > > > > > returns the proper address_space. It does this by
> > > > > > > > > > essentially checking the qualifiers of the type, which we
> > > > > > > > > > now attach to the `AttributedType` whereas before it was
> > > > > > > > > > attached to the modified type.
> > > > > > > > > >
> > > > > > > > > > This extra condition is necessary for ensuring that calling
> > > > > > > > > > `clang_getAddressSpace` points to the qualified
> > > > > > > > > > AttributedType instead of the unqualified modified type.
> > > > > > > > > My fear is that this will be breaking assumptions in
> > > > > > > > > third-party code. If someone disables
> > > > > > > > > `CXTranslationUnit_IncludeAttributedTypes`, they are unlikely
> > > > > > > > > to expect to receive an `AttributedType` and may react poorly
> > > > > > > > > to it.
> > > > > > > > Instead check if the type is address_space attributed and apply
> > > > > > > > the qualifiers the modified type.
> > > > > > > Sure, they can always modify their code to handle it gracefully,
> > > > > > > but it's a silent, breaking change to a somewhat stable API which
> > > > > > > is why I was prodding about it.
> > > > > > >
> > > > > > > After talking with @rsmith, we're thinking the correct change
> > > > > > > here is to return the attributed type when the user asks for it,
> > > > > > > but return the equivalent type rather than the modified type if
> > > > > > > the user doesn't want attribute sugar (for all attributes, not
> > > > > > > just address spaces). This way, when a user asks for CXType for
> > > > > > > one of these, they always get a correct type but sometimes it has
> > > > > > > attribute type sugar and sometimes it doesn't, depending on the
> > > > > > > parsing options.
> > > > > > >
> > > > > > > This is still a silent, breaking change in behavior, which is
> > > > > > > unfortunate. It should probably come with a mention in the
> > > > > > > release notes about the change to the API and some unit tests as
> > > > > > > well.
> > > > > > Ok. In the case of qualifiers then, should the equivalent type
> > > > > > still contain the address_space qualifiers when creating the
> > > > > > AttributedType?
> > > > > I believe so, yes -- that would ensure it's the minimally desugared
> > > > > type which the type is canonically equivalent to.
> > > > Sorry for the holdup. So for an AddressSpace AttributedType, we attach
> > > > the qualifiers only to the equivalent type.
> > > >
> > > > As for this though, the only problem I ran into with returning the
> > > > equivalent type is for AttributedTypes with `attr::ObjCKindOf`, a test
> > > > expects returning the modified type which is an `ObjCInterface` instead
> > > > of the equivalent type which is an `ObjCObject`. The test itself just
> > > > tests printing of a type, but I'm not sure how significant or
> > > > intentional printing this specific way was.
> > > Which test was failing because of this?
> > clang/test/Index/print-type.m
> Specifically just the check:
>
> ```
> CHECK: ParmDecl=p:6:36 (Definition) [type=__kindof Foo *]
> [typekind=ObjCObjectPointer] [canonicaltype=__kindof Foo *]
> [canonicaltypekind=ObjCObjectPointer] [basetype=Foo] [basekind=ObjCInterface]
> [isPOD=1] [pointeetype=Foo] [pointeekind=ObjCInterface]
> ```
>
> Where the last 2 fields we're instead `[pointeetype=__kindof Foo]
> [pointeekind=ObjCObject]` instead of what they are now.
I looked at the review adding the impacted test case and I did not have the
impression this was a principled decision so much as "that's what it prints". I
suspect we'd be fine removing the hack and always returning the equivalent
type, but ObjC is not my area of expertise.
Repository:
rC Clang
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D55447/new/
https://reviews.llvm.org/D55447
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