[LLVMdev] Find template types of std::map

[Sebastian Dreßler]

Hi,

for a current project I'm required to get the types of the template 
arguments key and value for std::map<K,V>. I've noticed that the STL 
implementation used by Clang defines the type of the map as

     %"class.std::map" = type { %"class.std::_Rb_tree" }

which then is further defined and finally ends as

     %"struct.std::_Rb_tree_node_base" = type {
         i32,
         %"struct.std::_Rb_tree_node_base"*,
         %"struct.std::_Rb_tree_node_base"*,
         %"struct.std::_Rb_tree_node_base"*
     }

However, indifferent what K and V are and how many different maps are 
instantiated, it always ends at this definition. But, I also noticed, that

     %"struct.std::pair" = type { i32, double }

is defined, which then provides the information I need.

Now the problem arises to connect %"class.std::map" to 
%"struct.std::pair" correctly. To solve this I looked at the IR and 
noticed, that the std::pair's are always defined in the reverse order of 
the definitions of std::map. So I think about using some index to find 
the correct std::pair.

 From this idea two issues arise:

1. I feel that this approach is not that stable as it should be, for 
instance, I think that the ordering of instantiation I'm making use of 
may change.

2. I'm unable to retrieve all defined named types from the module. I 
know there is LLVMContextImpl but this class is a forward declaration 
and therefore I'm not able to access LLVMContextImpl::NamedStructTypes.


Thanks for any suggestions.


Best regards,
Sebastian

-- 
Mit freundlichen Grüßen / Kind regards

Sebastian Dreßler

Zuse Institute Berlin (ZIB)
Takustraße 7
D-14195 Berlin-Dahlem
Germany

dressler at zib.de
Phone: +49 30 84185-261

http://www.zib.de/