[cfe-dev] What is a TypeRef, and how do you use it? (clang-c)

[Doug]

I'll just add to that, there's no problem getting the actual type for the
typedef vardecl; that works fine.

The problems I'm having are:

1) There's an extra symbol in the AST that doesn't seem to be related to
anything.

2) There's no obvious way to mark a param or var via its typedef rather
than the base type itself.

~
Doug.

On Sun, Nov 27, 2011 at 12:27 PM, Doug <douglas.linder at gmail.com> wrote:

> Hi again,
>
> Having a few more dramas with the clang-c api. Particularly Typedef's seem
> to behave oddly.
>
> If I do a dump of the ast for this code:
>
> struct x {
>   int y;
> };
>
> typedef struct x MyThing;
>
> extern MyThing *example;
>
> I get something along the lines of this from the parser:
>
> Symbol: x, Type: struct, Raw Kind: CXCursor_StructDecl
> Symbol: y, Type: int, Raw Kind: CXCursor_FieldDecl
> Symbol: MyThing, Type: record, Raw Kind: CXCursor_TypedefDecl
> Symbol: struct x, Type: record, Raw Kind: CXCursor_TypeRef
> Symbol: example, Type: record *, Raw Kind: CXCursor_VarDecl
> Symbol: MyThing, Type: record, Raw Kind: CXCursor_TypeRef
>
> In a slightly better format that's basically:
>
> x (struct) -> y (field)
> MyThing (Typedef)
> struct x (Typeref)
> example (Var)
> MyThing (Typeref)
>
> -_-
>
> What's going on here? Why is there a trailing Typeref symbol?
>
> The docs from TypeRef say:
>
>   /**
>    * \brief A reference to a type declaration.
>    *
>    * A type reference occurs anywhere where a type is named but not
>    * declared. For example, given:
>    *
>    * \code
>    * typedef unsigned size_type;
>    * size_type size;
>    * \endcode
>    *
>    * The typedef is a declaration of size_type (CXCursor_TypedefDecl),
>    * while the type of the variable "size" is referenced. The cursor
>    * referenced by the type of size is the typedef for size_type.
>    */
>
> So I suppose I'm supposed to use clang_getTypeDeclaration() on the Typeref
> to get the cursor for the typedef for something.
>
> Fair enough; I can use that from the 'struct x' TypeRef -> the MyType
> typedef.
>
>
> However, how can I relate the 'example' var to the related typedef?
>
> I presume that there is supposed to be some way to relate the trailing
> MyType --> example, and then MyType ---> the typedef.
>
>
> However, if I do a getSemanticParent() on the two nodes 'example' and
> 'MyType' (trailing) I get:
>
> 'example' -> (getSemanticParent) --> CXCursor_UnexposedDecl
> 'MyType' ->(getSemanticParent) --> CXCursor_FirstInvalid
>
> so....
>
> What now?
>
> Is this just not supported?
>
>
> help much appreciated!
>
> cheers,
> Doug.
>
>
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