[modules] Build a DAG of module macros for each identifier.

This graph will be used to determine the current set of active macros. This is
foundation work for getting macro visibility correct across submodules of the
current module. No functionality change for now.

llvm-svn: 235461

1 files changed, 7 insertions, 0 deletions

diff --git a/clang/lib/Lex/MacroInfo.cpp b/clang/lib/Lex/MacroInfo.cpp
index 5416886cc9f..046948397fd 100644
--- a/clang/lib/Lex/MacroInfo.cpp
+++ b/clang/lib/Lex/MacroInfo.cpp
@@ -234,3 +234,10 @@ void MacroDirective::dump() const {
   }
   Out << "\n";
 }
+
+ModuleMacro *ModuleMacro::create(Preprocessor &PP, unsigned OwningModuleID,
+                                 IdentifierInfo *II, MacroInfo *Macro,
+                                 ArrayRef<ModuleMacro*> Overrides) {
+  return new (PP.getPreprocessorAllocator())
+      ModuleMacro(OwningModuleID, II, Macro, Overrides);
+}