From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Mon, 8 May 2017 20:30:47 +0000 (+0000)
Subject: If we are building a module, and we read a second description of the same
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=977625bd6af0feaa1324925acb7c0689f10fa0b9;p=clang

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).


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@302463 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Lex/ModuleMap.cpp b/lib/Lex/ModuleMap.cpp
index 70d37d3d70..568894c32b 100644
--- a/lib/Lex/ModuleMap.cpp
+++ b/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))
diff --git a/test/Modules/preprocess-module.cpp b/test/Modules/preprocess-module.cpp
index a3b7892383..64af00c471 100644
--- a/test/Modules/preprocess-module.cpp
+++ b/test/Modules/preprocess-module.cpp
@@ -19,6 +19,11 @@
 // RUN: %clang_cc1 -fmodules -fmodule-name=file -fmodule-file=%t/fwd.pcm -x c++-module-map-cpp-output %t/no-rewrite.ii -emit-module -o %t/no-rewrite.pcm
 // RUN: %clang_cc1 -fmodules -fmodule-name=file -fmodule-file=%t/fwd.pcm -x c++-module-map-cpp-output %t/rewrite.ii -emit-module -o %t/rewrite.pcm
 
+// Check that we can load the original module map in the same compilation (this
+// could happen if we had a redundant -fmodule-map-file= in the original
+// build).
+// RUN: %clang_cc1 -fmodules -fmodule-name=file -fmodule-file=%t/fwd.pcm -fmodule-map-file=%S/Inputs/preprocess/module.modulemap -x c++-module-map-cpp-output %t/rewrite.ii -emit-module -o /dev/null
+
 // Check the module we built works.
 // RUN: %clang_cc1 -fmodules -fmodule-file=%t/no-rewrite.pcm %s -verify
 // RUN: %clang_cc1 -fmodules -fmodule-file=%t/rewrite.pcm %s -verify