Introduce the notion of name visibility into modules. For a given

(sub)module, all of the names may be hidden, just the macro names may
be exposed (for example, after the preprocessor has seen the import of
the module but the parser has not), or all of the names may be
exposed. Importing a module makes its names, and the names in any of
its non-explicit submodules, visible to name lookup (transitively).

This commit only introduces the notion of name visible and marks
modules and submodules as visible when they are imported. The actual
name-hiding logic in the AST reader will follow (along with test cases).

llvm-svn: 145586

1 files changed, 32 insertions, 0 deletions

diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index d43f8c1f45d..258baebc05c 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -2439,6 +2439,38 @@ ASTReader::ASTReadResult ASTReader::validateFileEntries(ModuleFile &M) {
   return Success;
 }
 
+void ASTReader::makeModuleVisible(Module *Mod, 
+                                  Module::NameVisibilityKind NameVisibility) {
+  llvm::SmallPtrSet<Module *, 4> Visited;
+  llvm::SmallVector<Module *, 4> Stack;
+  Stack.push_back(Mod);  
+  while (!Stack.empty()) {
+    Mod = Stack.back();
+    Stack.pop_back();
+
+    if (NameVisibility <= Mod->NameVisibility) {
+      // This module already has this level of visibility (or greater), so 
+      // there is nothing more to do.
+      continue;
+    }
+    
+    // Update the module's name visibility.
+    Mod->NameVisibility = NameVisibility;
+    
+    // FIXME: If we've already deserialized any names from this module,
+    // mark them as visible.
+    
+    // Push any non-explicit submodules onto the stack to be marked as
+    // visible.
+    for (llvm::StringMap<Module *>::iterator Sub = Mod->SubModules.begin(),
+                                          SubEnd = Mod->SubModules.end();
+         Sub != SubEnd; ++Sub) {
+      if (!Sub->getValue()->IsExplicit && Visited.insert(Sub->getValue()))
+        Stack.push_back(Sub->getValue());
+    }
+  }
+}
+
 ASTReader::ASTReadResult ASTReader::ReadAST(const std::string &FileName,
                                             ModuleKind Type) {
   switch(ReadASTCore(FileName, Type, /*ImportedBy=*/0)) {