If we are building a module, and we read a second description of the same

module from a different module map, ignore it.

This happens during builds of preprocessed modules (where it is harmless).

llvm-svn: 302463

1 files changed, 13 insertions, 1 deletions

diff --git a/clang/lib/Lex/ModuleMap.cpp b/clang/lib/Lex/ModuleMap.cpp
index 70d37d3d708..568894c32b9 100644
--- a/clang/lib/Lex/ModuleMap.cpp
+++ b/clang/lib/Lex/ModuleMap.cpp
@@ -1485,7 +1485,19 @@ void ModuleMapParser::parseModuleDecl() {
   
   // Determine whether this (sub)module has already been defined.
   if (Module *Existing = Map.lookupModuleQualified(ModuleName, ActiveModule)) {
-    if (Existing->DefinitionLoc.isInvalid() && !ActiveModule) {
+    // We might see a (re)definition of a module that we already have a
+    // definition for in two cases:
+    //  - If we loaded one definition from an AST file and we've just found a
+    //    corresponding definition in a module map file, or
+    bool LoadedFromASTFile = Existing->DefinitionLoc.isInvalid();
+    //  - If we're building a (preprocessed) module and we've just loaded the
+    //    module map file from which it was created.
+    bool ParsedAsMainInput =
+        Map.LangOpts.getCompilingModule() == LangOptions::CMK_ModuleMap &&
+        Map.LangOpts.CurrentModule == ModuleName &&
+        SourceMgr.getDecomposedLoc(ModuleNameLoc).first !=
+            SourceMgr.getDecomposedLoc(Existing->DefinitionLoc).first;
+    if (!ActiveModule && (LoadedFromASTFile || ParsedAsMainInput)) {
       // Skip the module definition.
       skipUntil(MMToken::RBrace);
       if (Tok.is(MMToken::RBrace))