LLDB’s module support (implemented here: http://llvm.org/svn/llvm-project/lldb/trunk/source/Expression/ClangModulesDeclVendor.cpp) sets up its own CompilerInstance and then loads modules into it.

The way we import macros from modules into expressions is by textual inclusion – we iterate across the macros like this:

–
if (m_compiler_instance->getPreprocessor().getExternalSource())
{
  m_compiler_instance->getPreprocessor().getExternalSource()->ReadDefinedMacros();
}


for (clang::Preprocessor::macro_iterator mi = m_compiler_instance->getPreprocessor().macro_begin(),
                                         me = m_compiler_instance->getPreprocessor().macro_end();
     mi != me; ++mi)
{
  // ...
  clang::MacroInfo *macro_info = nullptr;

        

  for (clang::ModuleMacro *module_macro : m_compiler_instance->getPreprocessor().getLeafModuleMacros(ii))
  {
    // pick the macro_info from the module we care most about; that might be NULL
  }

        

  if (macro_info)
  {
    // make a string from the macro
  }
}
–

What Im noticing is that a macro (say, “MAX”) doesn’t appear in the macro_begin() list at all.  Only later, after I’ve done a name lookup for “MAX" (on the assumption that it might be a variable, see ClangModulesDeclVendorImpl::FindDecls()), does it appear in the list.

Is there something else I need to tickle here, or is this a bug in the API?

Sean