getting parameter information from FunctionDecl class in clang

Question

How to get parameter information as a string from FunctionDecl class in clang . I'm trying but getting confused by so many inheritances. Also they compiler is saying that getReturnType() is not a member of FunctionDecl but doxygen documentation says otherwise . Please help. http://clang.llvm.org/doxygen/classclang_1_1FunctionDecl.html

using namespace std;
using namespace clang;
using namespace clang::driver;
using namespace clang::tooling;
using namespace llvm;

.......
class ExampleVisitor : public RecursiveASTVisitor<ExampleVisitor> 
{
    ......
    virtual bool VisitFunctionDecl(FunctionDecl *func) 
    {
            numFunctions++;
            string funcName = func->getNameInfo().getName().getAsString();
            string retName = func->getReturnType().getAsString();
            ...
            return true;
    }

}

Errors:-

‘class clang::FunctionDecl’ has no member named ‘getReturnType’

Assuming the documentation is correct: http://clang.llvm.org/doxygen/classclang_1_1FunctionDecl.html#a04fff4dba009b06065d218036092ebbb Where's that error coming from? Are you sure it's from that line? Can you try to fully qualify it with clang::FunctionDecl ? — Marco A., Jun 23 '14 at 11:01
That's weird, please go and check Decl.h for getReturnType(). If you don't have it you might have to update your clang sources — Marco A., Jun 23 '14 at 11:08
Yeah its not defined in Decl.h. I downloaded the source code from github as svn server was not working.Thanks . — Sourav Mukherjee, Jun 23 '14 at 11:18
o.k. sure. How to accept your answer ? I'm new to stack-overflow. — Sourav Mukherjee, Jun 23 '14 at 11:39

Marco A. · Accepted Answer · 2014-06-23T11:22:59.887

3

Depending if you need a qualified or unqualified name, you can stringify your return type and parameter names as follows

std::string retType = F->getReturnType().getAsString();
std::string arg0;
if(F->getNumParams() > 0)
  arg0 = F->parameters()[0]->getQualifiedNameAsString();

Check out the getAsString() method provided.

Edit: after your comments I figured out that you don't have the latest Clang source code. Please check it out before retrying. Good luck!

edited Jun 23 '14 at 11:22

answered Jun 23 '14 at 10:46

Marco A.

43,032
26
132
246

Then why is it saying that getReturnType() is not a member of FunctionDecl. – Sourav Mukherjee Jun 23 '14 at 11:03
Either that error is coming from somewhere else or you're getting the wrong FunctionDecl - GitHub repository mirror (https://github.com/llvm-mirror/clang/blob/master/include/clang/AST/Decl.h) – Marco A. Jun 23 '14 at 11:07

score 2 · Answer 2 · edited Oct 01 '15 at 18:35

2

try this,

getResultType()

rather than

getReturnType()

llvm 3.4 has no member getReturnType() but identical function whose name is getResultType() exists.

edited Oct 01 '15 at 18:35

Shawn Mehan

4,513
9
31
51

answered Oct 01 '15 at 17:54

user1553539

21
2

score 0 · Answer 3 · answered Jul 10 '15 at 05:18

0

To get all parameter list dynamically, below code would help.

string retName = func->getReturnType().getAsString();
for(int i=0; i<func->getNumParams(); i++)
{
    std::cout << " " << func->parameters()[i]->getQualifiedNameAsString();
}
...

answered Jul 10 '15 at 05:18

S S

920
1
17
34

score 0 · Answer 4 · answered Mar 25 '19 at 13:33

Here is a working function to print all the information about a FunctionDecl.Tested on Windows/LLVM6.0.0

void printFunctionDecl(FunctionDecl* f) 
{
    std::cout << "FunctionDecl@:"<<f<<":"
        << f->getReturnType().getAsString()<<" "
        << f->getQualifiedNameAsString()
        <<"(";

    for (int i = 0; i < f->getNumParams(); i++)
    {
        if (i > 0) std::cout << ",";             
        std::cout 
            << QualType::getAsString(f->parameters()[i]->getType().split()
                , PrintingPolicy{ {} })<<" "
            << f->parameters()[i]->getQualifiedNameAsString();          
    }

    std::cout << ")"
        <<"   Definition@"<<f->getDefinition()
        <<"\n";
}

getting parameter information from FunctionDecl class in clang

4 Answers4