From fcc54a3b91c9b429e0384238fbe42f73fec757ca Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Thu, 5 Jan 2012 00:12:00 +0000
Subject: [PATCH] If we already have a definition for a top-level module that
 we deserialized from a module file, don't bother parsing a new definition

llvm-svn: 147574
---
 clang/lib/Lex/ModuleMap.cpp | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/clang/lib/Lex/ModuleMap.cpp b/clang/lib/Lex/ModuleMap.cpp
index 42257f562439..6c13938c2094 100644
--- a/clang/lib/Lex/ModuleMap.cpp
+++ b/clang/lib/Lex/ModuleMap.cpp
@@ -790,6 +790,19 @@ void ModuleMapParser::parseModuleDecl() {
   
   // Determine whether this (sub)module has already been defined.
   if (Module *Existing = Map.lookupModuleQualified(ModuleName, ActiveModule)) {
+    if (Existing->DefinitionLoc.isInvalid() && !ActiveModule) {
+      // Skip the module definition.
+      skipUntil(MMToken::RBrace);
+      if (Tok.is(MMToken::RBrace))
+        consumeToken();
+      else {
+        Diags.Report(Tok.getLocation(), diag::err_mmap_expected_rbrace);
+        Diags.Report(LBraceLoc, diag::note_mmap_lbrace_match);
+        HadError = true;        
+      }
+      return;
+    }
+    
     Diags.Report(ModuleNameLoc, diag::err_mmap_module_redefinition)
       << ModuleName;
     Diags.Report(Existing->DefinitionLoc, diag::note_mmap_prev_definition);