Vendor import of clang trunk r241361:

https://llvm.org/svn/llvm-project/cfe/trunk@241361

1 files changed, 15 insertions, 2 deletions

diff --git a/lib/Lex/PPLexerChange.cpp b/lib/Lex/PPLexerChange.cpp
index 1a35d32..c231e18 100644
--- a/lib/Lex/PPLexerChange.cpp
+++ b/lib/Lex/PPLexerChange.cpp
@@ -644,11 +644,20 @@ void Preprocessor::EnterSubmodule(Module *M, SourceLocation ImportLoc) {
   if (FirstTime) {
     // Determine the set of starting macros for this submodule; take these
     // from the "null" module (the predefines buffer).
+    //
+    // FIXME: If we have local visibility but not modules enabled, the
+    // NullSubmoduleState is polluted by #defines in the top-level source
+    // file.
     auto &StartingMacros = NullSubmoduleState.Macros;
 
     // Restore to the starting state.
     // FIXME: Do this lazily, when each macro name is first referenced.
     for (auto &Macro : StartingMacros) {
+      // Skip uninteresting macros.
+      if (!Macro.second.getLatest() &&
+          Macro.second.getOverriddenMacros().empty())
+        continue;
+
       MacroState MS(Macro.second.getLatest());
       MS.setOverriddenMacros(*this, Macro.second.getOverriddenMacros());
       State.Macros.insert(std::make_pair(Macro.first, std::move(MS)));
@@ -732,6 +741,11 @@ void Preprocessor::LeaveSubmodule() {
     }
   }
 
+  // FIXME: Before we leave this submodule, we should parse all the other
+  // headers within it. Otherwise, we're left with an inconsistent state
+  // where we've made the module visible but don't yet have its complete
+  // contents.
+
   // Put back the outer module's state, if we're tracking it.
   if (getLangOpts().ModulesLocalVisibility)
     CurSubmoduleState = Info.OuterSubmoduleState;
@@ -739,6 +753,5 @@ void Preprocessor::LeaveSubmodule() {
   BuildingSubmoduleStack.pop_back();
 
   // A nested #include makes the included submodule visible.
-  if (!BuildingSubmoduleStack.empty() || !getLangOpts().ModulesLocalVisibility)
-    makeModuleVisible(LeavingMod, ImportLoc);
+  makeModuleVisible(LeavingMod, ImportLoc);
 }