[ASTImporter] Added visibility context check for TypedefNameDecl.

Summary:
ASTImporter makes now difference between typedefs and type aliases
with same name in different translation units
if these are not visible outside.

Reviewers: martong, a.sidorin, shafik, a_sidorin

Reviewed By: martong, shafik

Subscribers: rnkovacs, dkrupp, Szelethus, gamesh411, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D64480

llvm-svn: 370903

1 files changed, 27 insertions, 13 deletions

diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index 417a97c..e541aaf 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -932,6 +932,27 @@ Expected<LambdaCapture> ASTNodeImporter::import(const LambdaCapture &From) {
       EllipsisLoc);
 }
 
+template <typename T>
+bool ASTNodeImporter::hasSameVisibilityContext(T *Found, T *From) {
+  if (From->hasExternalFormalLinkage())
+    return Found->hasExternalFormalLinkage();
+  if (Importer.GetFromTU(Found) != From->getTranslationUnitDecl())
+    return false;
+  if (From->isInAnonymousNamespace())
+    return Found->isInAnonymousNamespace();
+  else
+    return !Found->isInAnonymousNamespace() &&
+           !Found->hasExternalFormalLinkage();
+}
+
+template <>
+bool ASTNodeImporter::hasSameVisibilityContext(TypedefNameDecl *Found,
+                                               TypedefNameDecl *From) {
+  if (From->isInAnonymousNamespace() && Found->isInAnonymousNamespace())
+    return Importer.GetFromTU(Found) == From->getTranslationUnitDecl();
+  return From->isInAnonymousNamespace() == Found->isInAnonymousNamespace();
+}
+
 } // namespace clang
 
 //----------------------------------------------------------------------------
@@ -2344,6 +2365,9 @@ ASTNodeImporter::VisitTypedefNameDecl(TypedefNameDecl *D, bool IsAlias) {
   // If this typedef is not in block scope, determine whether we've
   // seen a typedef with the same name (that we can merge with) or any
   // other entity by that name (which name lookup could conflict with).
+  // Note: Repeated typedefs are not valid in C99:
+  // 'typedef int T; typedef int T;' is invalid
+  // We do not care about this now.
   if (!DC->isFunctionOrMethod()) {
     SmallVector<NamedDecl *, 4> ConflictingDecls;
     unsigned IDNS = Decl::IDNS_Ordinary;
@@ -2352,6 +2376,9 @@ ASTNodeImporter::VisitTypedefNameDecl(TypedefNameDecl *D, bool IsAlias) {
       if (!FoundDecl->isInIdentifierNamespace(IDNS))
         continue;
       if (auto *FoundTypedef = dyn_cast<TypedefNameDecl>(FoundDecl)) {
+        if (!hasSameVisibilityContext(FoundTypedef, D))
+          continue;
+
         QualType FromUT = D->getUnderlyingType();
         QualType FoundUT = FoundTypedef->getUnderlyingType();
         if (Importer.IsStructurallyEquivalent(FromUT, FoundUT)) {
@@ -3022,19 +3049,6 @@ Error ASTNodeImporter::ImportFunctionDeclBody(FunctionDecl *FromFD,
   return Error::success();
 }
 
-template <typename T>
-bool ASTNodeImporter::hasSameVisibilityContext(T *Found, T *From) {
-  if (From->hasExternalFormalLinkage())
-    return Found->hasExternalFormalLinkage();
-  if (Importer.GetFromTU(Found) != From->getTranslationUnitDecl())
-    return false;
-  if (From->isInAnonymousNamespace())
-    return Found->isInAnonymousNamespace();
-  else
-    return !Found->isInAnonymousNamespace() &&
-           !Found->hasExternalFormalLinkage();
-}
-
 ExpectedDecl ASTNodeImporter::VisitFunctionDecl(FunctionDecl *D) {
 
   SmallVector<Decl *, 2> Redecls = getCanonicalForwardRedeclChain(D);