Clang AST: Unused methods of class templates don't appear in AST

Question

I am working on a source-to-source conversion tool, using Clang's AST via libTooling.

There is one problem which I can't seem to workaround. Consider the following C++ code:

template<typename T>
struct s {
    void lazy1() {}
    void lazy2() {} // unused
};

int main() {
    s<int> inst;
    inst.lazy1();
    return 0;
}

In Clang's AST, definition of lazy1() is fully available (i.e., a CompoundStmt exists as child), while lazy2() has no children:

[...]
`-ClassTemplateSpecializationDecl 0x7de4a8 <line:1:1, line:5:1> line:2:8 struct s definition
[...]
  |-CXXMethodDecl 0x7de790 <line:3:2, col:16> col:7 used lazy1 'void ()'
  | `-CompoundStmt 0x7de310 <col:15, col:16>
  |-CXXMethodDecl 0x7de840 <line:4:2, col:16> col:7 lazy2 'void ()'
[...]

As I understand, Clang only emits method definitions if they are actually used. In this example, lazy2() is unused and I can't access any definition data in the AST.

I need to access all method definitions of all template specializations.

I am interested in a non-hacky, reliable solution. I am ready to patch Clang, if necessary. I've already tried this answer on Stackoverflow, however, in my case it doesn't work.

Clang AST: Unused methods of class templates don't appear in AST

0 Answers0