[cfe-dev] problem with template class inheritance and cursor api

[Anders Bakken]

On Jan 18, 2013, at 9:43 AM, Argyrios Kyrtzidis <akyrtzi at gmail.com> wrote:

> On Jan 18, 2013, at 12:38 AM, Anders Bakken <agbakken at gmail.com> wrote:
> 
>> Hi
>> 
>> I'm writing a clang-based c++/c indexer
>> (https://github.com/Andersbakken/rtags/) and I am having a problem
>> with the following construct:
>> 
>> // -----------------
>> template <typename T>
>> class A
>> {
>> public:
>>   int size() const { return 1; }
>> };
>> 
>> template <typename T>
>> class B : public A<T>
>> {
>> public:
>>   bool isEmpty() const { return A<T>::size(); }
>> };
>> 
>> // -----------------
>> 
>> There seems to be way to get from this cursor(s) for the call to
>> A<T>::size() to the actual function (A<T>::size).
>> 
>> I provide functionality to jump to target cursor and this one has been
>> me causing me some problems.
>> 
>> With the attached example I get the following output:
>> 
>> main.cpp:2:7 (28, 0-76) kind: ClassTemplate display name: A<T> usr:
>> c:@CT>1#T at A definition
>> main.cpp:1:20 (19, 10-20) kind: TemplateTypeParameter display name:
>> T usr: c:main.cpp at 10 definition
>> main.cpp:4:1 (32, 32-39) kind: CXXAccessSpecifier usr: c: definition
>> main.cpp:5:9 (48, 44-74) kind: CXXMethod display name: size() usr:
>> c:@CT>1#T at A@F at size#1 definition
>>   main.cpp:5:22 (61, 61-74) kind: CompoundStmt
>>     main.cpp:5:24 (63, 63-71) kind: ReturnStmt
>>       main.cpp:5:31 (70, 70-71) kind: IntegerLiteral
>> main.cpp:9:7 (107, 79-184) kind: ClassTemplate display name: B<T> usr:
>> c:@CT>1#T at B definition
>> main.cpp:8:20 (98, 89-99) kind: TemplateTypeParameter display name:
>> T usr: c:main.cpp at 89 definition
>> main.cpp:9:18 (118, 111-122) kind: C++ base class specifier display
>> name: A<T>
>> -> main.cpp:2:7 (28, 0-76) kind: ClassTemplate display name: A<T>
>> usr: c:@CT>1#T at A definition
>>   main.cpp:9:18 (118, 118-119) kind: TemplateRef display name: A
>>   -> main.cpp:2:7 (28, 0-76) kind: ClassTemplate display name: A<T>
>> usr: c:@CT>1#T at A definition
>>   main.cpp:9:20 (120, 120-121) kind: TypeRef display name: T
>>   -> main.cpp:8:20 (98, 89-99) kind: TemplateTypeParameter display
>> name: T usr: c:main.cpp at 89 definition
>> main.cpp:11:1 (125, 125-132) kind: CXXAccessSpecifier usr: c: definition
>> main.cpp:12:10 (142, 137-182) kind: CXXMethod display name:
>> isEmpty() usr: c:@CT>1#T at B@F at isEmpty#1 definition
>>   main.cpp:12:26 (158, 158-182) kind: CompoundStmt
>>     main.cpp:12:28 (160, 160-179) kind: ReturnStmt
>>       main.cpp:12:35 (167, 167-179) kind: CallExpr
>>         main.cpp:12:35 (167, 167-177) kind: MemberRefExpr
>>           main.cpp:12:35 (167, 167-168) kind: TemplateRef display name: A
>>           -> main.cpp:2:7 (28, 0-76) kind: ClassTemplate display
>> name: A<T> usr: c:@CT>1#T at A definition
>>           main.cpp:12:37 (169, 169-170) kind: TypeRef display name: T
>>           -> main.cpp:8:20 (98, 89-99) kind: TemplateTypeParameter
>> display name: T usr: c:main.cpp at 89 definition
>> 
>> I've tried out all the APIs I could find to look up the connection but
>> I have been unsuccessful and had to resort to hacks to make it work.
>> Is there way to do this? Is it a bug?
> 
> There is no way currently. From the compiler's perspective 'size' does not bind to any function until instantiation time, but libclang could try to do some extra lookups in clang_getCursorDefinition instead of giving up.
> Please file a bug in bugzilla (and patches are welcome as always :-)
> 
> -Argyrios


Ah. Thanks. I guess that makes sense. For tools like mine it's a bit inconvenient though. I'll file a bug report. 
> 
> 
>> 
>> Help would be greatly appreciated.
>> 
>> I really am very grateful for your excellent work on this project that
>> allows me to bring my emacs c++ experience into the 21st century :-)
>> 
>> regards
>> 
>> Anders
>> <clangtest.c><foo.cpp>_______________________________________________
>> cfe-dev mailing list
>> cfe-dev at cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
>