PR33552: Distinguish between declarations that are owned by no module and

declarations that are owned but unconditionally visible.

This allows us to set declarations as visible even if they have a local owning
module, without losing information. In turn, that means that our Objective-C
support can keep on incorrectly assuming the "hidden" bit on the declaration is
the whole story with regard to name visibility. This will also be useful once
we support the C++ Modules TS export semantics.

Objective-C name visibility is still incorrect in any case where the "hidden"
bit is not the complete story: for instance, in Objective-C++ the set of
visible categories will be wrong during template instantiation, and with local
submodule visibility enabled it will be wrong when building modules. Fixing that
will require a major overhaul of how visibility is handled for Objective-C (and
particularly for categories).

llvm-svn: 306075

1 files changed, 13 insertions, 15 deletions

diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
index 3cc3a8efae3..07ab421cfc5 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -522,31 +522,29 @@ void ASTDeclReader::VisitDecl(Decl *D) {
   D->setTopLevelDeclInObjCContainer(Record.readInt());
   D->setAccess((AccessSpecifier)Record.readInt());
   D->FromASTFile = true;
-  D->setModulePrivate(Record.readInt());
-  D->Hidden = D->isModulePrivate();
+  bool ModulePrivate = Record.readInt();
 
   // Determine whether this declaration is part of a (sub)module. If so, it
   // may not yet be visible.
   if (unsigned SubmoduleID = readSubmoduleID()) {
     // Store the owning submodule ID in the declaration.
+    D->setModuleOwnershipKind(
+        ModulePrivate ? Decl::ModuleOwnershipKind::ModulePrivate
+                      : Decl::ModuleOwnershipKind::VisibleWhenImported);
     D->setOwningModuleID(SubmoduleID);
 
-    if (D->Hidden) {
-      // Module-private declarations are never visible, so there is no work to do.
+    if (ModulePrivate) {
+      // Module-private declarations are never visible, so there is no work to
+      // do.
     } else if (Reader.getContext().getLangOpts().ModulesLocalVisibility) {
       // If local visibility is being tracked, this declaration will become
-      // hidden and visible as the owning module does. Inform Sema that this
-      // declaration might not be visible.
-      D->Hidden = true;
+      // hidden and visible as the owning module does.
     } else if (Module *Owner = Reader.getSubmodule(SubmoduleID)) {
-      if (Owner->NameVisibility != Module::AllVisible) {
-        // The owning module is not visible. Mark this declaration as hidden.
-        D->Hidden = true;
-
-        // Note that this declaration was hidden because its owning module is 
-        // not yet visible.
+      // Mark the declaration as visible when its owning module becomes visible.
+      if (Owner->NameVisibility == Module::AllVisible)
+        D->setVisibleDespiteOwningModule();
+      else
         Reader.HiddenNamesMap[Owner].push_back(D);
-      }
     }
   }
 }
@@ -4144,7 +4142,7 @@ void ASTDeclReader::UpdateDecl(Decl *D) {
         Reader.HiddenNamesMap[Owner].push_back(Exported);
       } else {
         // The declaration is now visible.
-        Exported->Hidden = false;
+        Exported->setVisibleDespiteOwningModule();
       }
       break;
     }