[cfe-dev] Getting meta-data into Clang's AST

[Sean Hunt]

On 07/08/2010 03:01 AM, Jan Bierbaum wrote:
> But to make use of the C++0x style attributes you have to use the
> -std=c++0x option, correct?

Currently, yes. Also note that the implementation is a little outdated; 
there were changes to the way attributes are parsed in the most recent 
draft and those are not reflected in the source.

> Is it possible to add custom attributes to Clang without changing it's
> code? Are there any hooks? I'm trying to build on top of the binary
> distribution of LLVM and Clang just using their libs. Up to now I found
> hooks in the preprocessor to add pragma and comment handlers but nothing
> for attributes.

No. Adding custom attribute hooks is a good idea, and I'll consider it 
after I finish my current attribute rewrite.

> When I just add some custom attributes to the source they are parse
> without any error but then just discarded. All I need is to have them in
> the AST besides the built-in ones.

To do this much, you would need to currently add the attribute to 
include/clang/Basic/Attr.td, include/clang/AST/Attr.h, 
include/clang/Parse/AttributeList.h, lib/Parse/AttributeList.cpp, and 
lib/Sema/SemaDeclAttr.cpp, I believe. If you want them to use the C++0x 
syntax, you would additionally need to look at 
lib/Parse/ParseDeclCXX.cpp, near the bottom.

My project is to simplify this process somewhat, but it's currently 
somewhat stuck awaiting reply from the GCC devs about their attribute 
syntax.

Sean