Ignore missing headers with clang AST parser

Question

I'm on Windows, using MSVC to compile my project, but I need clang for its neat AST parser, which allow me to write a little code generator.
Problem is, clang cannot parse MSVC headers (a very-well known and understandable problem).

I tried two options :

1. I include MSVC header folder, parsing the built-in headers included in my code will end-up leading to a fatal error at some point, preventing me from parsing the parts I want correctly.
2. What I did before is simply not provide any built-in headers and forward declare the types I needed. It worked fine and somehow it doesn't anymore with latest Clang. I don't really know if the parser policy on missing header changed, but it is causing complete failure every time something like <string> is included and not much get parsed.

I am using the python bindings (libclang), but I would consider switching to C/C++ API if there would be a solution there.

Is there anyway I can alter this behavior and make clang continue parsing even when some headers are not found ?

Answer 1

Use SetSuppressIncludeNotFoundError. Took me an hour to find! You can imagine how glad I was to find it!

https://clang.llvm.org/doxygen/classclang_1_1Preprocessor.html#ac7bafe67fc32e41460855b39d20ff6af

Answer 2

One way to ignore the errors due to missing headers is to set SetSuppressIncludeNotFoundError to true in your definition of ASTFrontendAction. An example for the same is given below.

{
public:
    virtual std::unique_ptr<clang::ASTConsumer> CreateASTConsumer(
        clang::CompilerInstance &Compiler, llvm::StringRef InFile)
    {
        Compiler.getPreprocessor().SetSuppressIncludeNotFoundError(true);
        return std::unique_ptr<clang::ASTConsumer>(
            new CustomASTConsumer(&Compiler.getASTContext()));
    }
};

For a complete example using ASTFrontendAction, please visit at https://clang.llvm.org/docs/RAVFrontendAction.html