[cfe-dev] Mocking via Clang

[Eran Jakoby via cfe-dev]

Hi,
I'm trying to utilize Clang for mocking.
Starting for simplicity from C language - I would like to create:

1.       Identical function for each function found (e.g. foo_wrapper() for foo()).

2.       All calls to original function (e.g. foo()) should instead call the wrapper (e.g. foo_wrapper()).
(the wrappers themselves can be left as undefined symbols to be resolved in link).

I started by using Clang plug-in with a RecursiveASTVisitor that when visiting a function does the following code: (the visitor is called from HandleTopLevelDecl of an ASTConsumer)
                                FunctionDecl* NewFD=FunctionDecl::Create(getContext(), getContext().getTranslationUnitDecl(), f->getSourceRange().getBegin(), f->getSourceRange().getEnd(), DeclarationName(&newNameIdInfo), f->getReturnType(), f->getTypeSourceInfo(), f->getStorageClass());
                                NewFD->setLexicalDeclContext(getContext().getTranslationUnitDecl());
                                SmallVector<ParmVarDecl*, 16> Params;
                                for(auto iter = f->param_begin(); iter!=f->param_end(); ++iter) {
                                                Params.push_back(*iter);
                                }
                                NewFD->setParams(Params);

However this does not work and does not add an identical function to be used as wrapper (using nm I don't see the wrapper function symbol).
Moreover I have no idea how afterwards to set all calls to foo_wrapper instead of foo.

Is my general approach correct? Am I missing something?
Any advice would be greatly appreciated.
Thanks!
Eran

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