[cfe-dev] Getting template arguments (as written) from a function template specialization.

[Douglas Gregor]

Hello Enea,

On May 20, 2010, at 7:12 AM, Enea Zaffanella wrote:

> Hello.
> 
> We would like to retrieve a TemplateArgumentListInfo (or equivalent 
> information) from a FunctionDecl node representing an explicit function 
> template specialization.
> 
> The FunctionTemplateSpecializationInfo structure only encodes the 
> semantic form of the template arguments, i.e., a TemplateArgumentList*.

Right.

> Would it be OK to also add a TemplateArgumentListInfo*?

Yes!

> We noted that FunctionTemplateSpecializationInfo are profiled.
> As far as we understand, the new data member should not be used in the 
> profiling step. (Correct?)

Correct. The spelling of the arguments does not affect the semantics.

> If the proposal above is OK, then probably all we will need to do in 
> this first step is to modify calls to function
>    FunctionDecl::setFunctionTemplateSpecialization()
> inside
>    Sema::CheckFunctionTemplateSpecialization()

Correct.

> In a second step, we will consider whether or not a similar change is 
> required when building explicit instantiations of function templates 
> (rather than specializations) ... things should not be much different. 

It should be very similar.

> Are there other issues we may be missing?

IIRC, we don't keep track of all of the function template specializations or explicit instantiations that occur for a given function template with a given set of template arguments within a DeclContext, so there might be more work to do to ensure that all of the specializations and instantiations show up. For example, our -ast-dump output for

  template<typename T> void f(T);
  template<> void f<int>(int);
  template<> void f(int);
  template void f(int)

is fairly sparse :)

	- Doug