4 files changed, 34 insertions, 0 deletions
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 687a6ca8d33..42a8cd800fa 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -1556,6 +1556,12 @@ static void addLinkOptionsPostorder(CodeGenModule &CGM, Module *Mod,
   // Add linker options to link against the libraries/frameworks
   // described by this module.
   llvm::LLVMContext &Context = CGM.getLLVMContext();
+
+  // For modules that use export_as for linking, use that module
+  // name instead.
+  if (Mod->UseExportAsModuleLinkName)
+    return;
+
   for (unsigned I = Mod->LinkLibraries.size(); I > 0; --I) {
     // Link against a framework.  Frameworks are currently Darwin only, so we
     // don't to ask TargetCodeGenInfo for the spelling of the linker option.
diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index b8f55b61427..f57246bec09 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -1979,6 +1979,12 @@ CompilerInstance::loadModule(SourceLocation ImportLoc,
                      Module, ImportLoc);
   }
 
+  // Resolve any remaining module using export_as for this one.
+  getPreprocessor()
+      .getHeaderSearchInfo()
+      .getModuleMap()
+      .resolveLinkAsDependencies(TopModule);
+
   LastModuleImportLoc = ImportLoc;
   LastModuleImportResult = ModuleLoadResult(Module);
   return LastModuleImportResult;
diff --git a/clang/lib/Lex/ModuleMap.cpp b/clang/lib/Lex/ModuleMap.cpp
index a711e1ddf84..e47abd50f17 100644
--- a/clang/lib/Lex/ModuleMap.cpp
+++ b/clang/lib/Lex/ModuleMap.cpp
@@ -54,6 +54,24 @@
 
 using namespace clang;
 
+void ModuleMap::resolveLinkAsDependencies(Module *Mod) {
+  auto PendingLinkAs = PendingLinkAsModule.find(Mod->Name);
+  if (PendingLinkAs != PendingLinkAsModule.end()) {
+    for (auto &Name : PendingLinkAs->second) {
+      auto *M = findModule(Name.getKey());
+      if (M)
+        M->UseExportAsModuleLinkName = true;
+    }
+  }
+}
+
+void ModuleMap::addLinkAsDependency(Module *Mod) {
+  if (findModule(Mod->ExportAsModule))
+    Mod->UseExportAsModuleLinkName = true;
+  else
+    PendingLinkAsModule[Mod->ExportAsModule].insert(Mod->Name);
+}
+
 Module::HeaderKind ModuleMap::headerRoleToKind(ModuleHeaderRole Role) {
   switch ((int)Role) {
   default: llvm_unreachable("unknown header role");
@@ -2412,6 +2430,8 @@ void ModuleMapParser::parseExportAsDecl() {
   }
   
   ActiveModule->ExportAsModule = Tok.getString();
+  Map.addLinkAsDependency(ActiveModule);
+
   consumeToken();
 }
 
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 9e832509a95..179f25e1c80 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -5171,6 +5171,7 @@ ASTReader::ReadSubmoduleBlock(ModuleFile &F, unsigned ClientLoadCapabilities) {
       break;
 
     case SUBMODULE_LINK_LIBRARY:
+      ModMap.resolveLinkAsDependencies(CurrentModule);
       CurrentModule->LinkLibraries.push_back(
                                          Module::LinkLibrary(Blob, Record[0]));
       break;
@@ -5203,6 +5204,7 @@ ASTReader::ReadSubmoduleBlock(ModuleFile &F, unsigned ClientLoadCapabilities) {
 
     case SUBMODULE_EXPORT_AS:
       CurrentModule->ExportAsModule = Blob.str();
+      ModMap.addLinkAsDependency(CurrentModule);
       break;
     }
   }