1 files changed, 39 insertions, 8 deletions

diff --git a/clang/lib/Lex/ModuleMap.cpp b/clang/lib/Lex/ModuleMap.cpp
index 8dead93..0e148a4 100644
--- a/clang/lib/Lex/ModuleMap.cpp
+++ b/clang/lib/Lex/ModuleMap.cpp
@@ -888,23 +888,30 @@ ModuleMap::createPrivateModuleFragmentForInterfaceUnit(Module *Parent,
   return Result;
 }
 
-Module *ModuleMap::createModuleForInterfaceUnit(SourceLocation Loc,
-                                                StringRef Name) {
-  assert(LangOpts.CurrentModule == Name && "module name mismatch");
-  assert(!Modules[Name] && "redefining existing module");
-
+Module *ModuleMap::createModuleUnitWithKind(SourceLocation Loc, StringRef Name,
+                                            Module::ModuleKind Kind) {
   auto *Result =
       new Module(Name, Loc, nullptr, /*IsFramework*/ false,
                  /*IsExplicit*/ false, NumCreatedModules++);
-  Result->Kind = Module::ModuleInterfaceUnit;
-  Modules[Name] = SourceModule = Result;
+  Result->Kind = Kind;
 
-  // Reparent the current global module fragment as a submodule of this module.
+  // Reparent any current global module fragment as a submodule of this module.
   for (auto &Submodule : PendingSubmodules) {
     Submodule->setParent(Result);
     Submodule.release(); // now owned by parent
   }
   PendingSubmodules.clear();
+  return Result;
+}
+
+Module *ModuleMap::createModuleForInterfaceUnit(SourceLocation Loc,
+                                                StringRef Name) {
+  assert(LangOpts.CurrentModule == Name && "module name mismatch");
+  assert(!Modules[Name] && "redefining existing module");
+
+  auto *Result =
+      createModuleUnitWithKind(Loc, Name, Module::ModuleInterfaceUnit);
+  Modules[Name] = SourceModule = Result;
 
   // Mark the main source file as being within the newly-created module so that
   // declarations and macros are properly visibility-restricted to it.
@@ -915,6 +922,30 @@ Module *ModuleMap::createModuleForInterfaceUnit(SourceLocation Loc,
   return Result;
 }
 
+Module *ModuleMap::createModuleForImplementationUnit(SourceLocation Loc,
+                                                     StringRef Name) {
+  assert(LangOpts.CurrentModule == Name && "module name mismatch");
+  // The interface for this implementation must exist and be loaded.
+  assert(Modules[Name] && Modules[Name]->Kind == Module::ModuleInterfaceUnit &&
+         "creating implementation module without an interface");
+
+  // Create an entry in the modules map to own the implementation unit module.
+  // User module names must not start with a period (so that this cannot clash
+  // with any legal user-defined module name).
+  StringRef IName = ".ImplementationUnit";
+  assert(!Modules[IName] && "multiple implementation units?");
+
+  auto *Result =
+      createModuleUnitWithKind(Loc, Name, Module::ModuleImplementationUnit);
+  Modules[IName] = SourceModule = Result;
+
+  // Check that the main file is present.
+  assert(SourceMgr.getFileEntryForID(SourceMgr.getMainFileID()) &&
+         "no input file for module implementation");
+
+  return Result;
+}
+
 Module *ModuleMap::createHeaderUnit(SourceLocation Loc, StringRef Name,
                                     Module::Header H) {
   assert(LangOpts.CurrentModule == Name && "module name mismatch");