CLang Libtooling: fetching datatype of a variable inside clang::VarDecl, clang::FieldDecl or clang::ParmVarDecl

Question

I am working on CLang 3.5. I am trying to fetch info about variables declared in a C++ project.

How can I fetch datatype or qualified class name of a variable in a clang::VarDecl, clang::FieldDecl or clang::ParmVarDecl object? I tried to find a function which can return datatype or class name of the variable in doc for clang::VarDecl provided here.

http://clang.llvm.org/doxygen/classclang_1_1VarDecl.html

I also tried to look into the code of $LLVM/tools/clang/tools/clang-check/ClangCheck.cpp because on passing cmd arg --ast-dump it shows all of the information about every AST node including all of the variables declared. I wonder how to access all of that information.

I am using ASTMatchers to find my variable declarations, those are:

fieldDecl().bind("field")
parmVarDecl().bind("param")
varDecl().bind("var")

Can anybody please tell me how can I get datatype of all of the variables delcared?

Answer 1

Recently, I'm learning Clang and I've wrote some codes after reading this question. It might help you.

Full source code is available in github.com (see ex04.cc)

DeclarationMatcher FieldDeclMatcher =
    clang::ast_matchers::fieldDecl().bind("field_decl");

class LoopPrinter : public MatchFinder::MatchCallback
{
public :
    virtual void run(const MatchFinder::MatchResult& result)
    {
        if (const clang::FieldDecl* fd
            = result.Nodes.getNodeAs<clang::FieldDecl>("field_decl"))
        {
            std::cout << "======== FieldDecl found ======" << std::endl;

            const clang::RecordDecl* rd = fd->getParent();
            const clang::QualType qt = fd->getType();
            const clang::Type* t = qt.getTypePtr();

            std::cout << "FieldDecl found '"
                      << fd->getQualifiedNameAsString() << " "
                      << fd->getName().str() << "' in '"
                      << rd->getName().str() << "'. "
                      << "is Builtintype = " << t->isBuiltinType() << " "
                      << std::endl << std::endl;
        }

    } // end of run()
};