[cfe-dev] macro_begin()/macro_end()

[Sean Callanan]

Richard,

thanks for getting back to me!  The fix you proposed resolved the bug for me – and removing the code you said was redundant also worked fine.

Sean

> On Jul 29, 2015, at 5:36 PM, Richard Smith <richard at metafoo.co.uk> wrote:
> 
> On Wed, Jul 29, 2015 at 5:35 PM, Richard Smith <richard at metafoo.co.uk <mailto:richard at metafoo.co.uk>> wrote:
> On Wed, Jul 29, 2015 at 10:43 AM, Sean Callanan <scallanan at apple.com <mailto:scallanan at apple.com>> wrote:
> LLDB’s module support (implemented here: http://llvm.org/svn/llvm-project/lldb/trunk/source/Expression/ClangModulesDeclVendor.cpp <https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_svn_llvm-2Dproject_lldb_trunk_source_Expression_ClangModulesDeclVendor.cpp&d=AwMFaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=CnzuN65ENJ1H9py9XLiRvC_UQz6u3oG6GUNn7_wosSM&m=qJ7PzNcXqcUiCKOoFs9S4BDpb3TOf64WitZDB3JoLdM&s=WSvUUkZckMbgeN5UAaJKYWcqxxQzarzUBnC0_xfDRZ4&e=>) 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();
> 
> FYI, this is redundant; macro_begin does this for you.
>  
> }
> 
> 
> 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?
> 
> Does this help:
> 
> Index: lib/Serialization/ASTReader.cpp
> ===================================================================
> --- lib/Serialization/ASTReader.cpp     (revision 243368)
> +++ lib/Serialization/ASTReader.cpp     (working copy)
> @@ -1623,7 +1623,7 @@
> 
>          case PP_MACRO_OBJECT_LIKE:
>          case PP_MACRO_FUNCTION_LIKE:
> -          getLocalIdentifier(**I, Record[0]);
> +          updateOutOfDateIdentifier(*getLocalIdentifier(**I, Record[0]));
>            break;
> 
>          case PP_TOKEN:
> 
> 

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