Implement Itanium name mangling support for C++ Modules TS.

This follows the scheme agreed with Nathan Sidwell, which can be found here:

  https://gcc.gnu.org/wiki/cxx-modules?action=AttachFile

This will be proposed to the itanium-cxx-abi list once we have some experience
with how well it works; the ABI for this TS should be considered unstable until
it is part of the Itanium C++ ABI.

llvm-svn: 312467

1 files changed, 16 insertions, 2 deletions

diff --git a/clang/lib/Sema/Sema.cpp b/clang/lib/Sema/Sema.cpp
index e99e73fc8da..66cb4976dac 100644
--- a/clang/lib/Sema/Sema.cpp
+++ b/clang/lib/Sema/Sema.cpp
@@ -766,10 +766,24 @@ void Sema::emitAndClearUnusedLocalTypedefWarnings() {
 /// declarations.
 void Sema::ActOnStartOfTranslationUnit() {
   if (getLangOpts().ModulesTS) {
+    SourceLocation StartOfTU =
+        SourceMgr.getLocForStartOfFile(SourceMgr.getMainFileID());
+
     // We start in the global module; all those declarations are implicitly
     // module-private (though they do not have module linkage).
-    Context.getTranslationUnitDecl()->setModuleOwnershipKind(
-        Decl::ModuleOwnershipKind::ModulePrivate);
+    auto &Map = PP.getHeaderSearchInfo().getModuleMap();
+    auto *GlobalModule = Map.createGlobalModuleForInterfaceUnit(StartOfTU);
+    assert(GlobalModule && "module creation should not fail");
+
+    // Enter the scope of the global module.
+    ModuleScopes.push_back({});
+    ModuleScopes.back().Module = GlobalModule;
+    VisibleModules.setVisible(GlobalModule, StartOfTU);
+
+    // All declarations created from now on are owned by the global module.
+    auto *TU = Context.getTranslationUnitDecl();
+    TU->setModuleOwnershipKind(Decl::ModuleOwnershipKind::Visible);
+    TU->setLocalOwningModule(GlobalModule);
   }
 }