3 files changed, 15 insertions, 37 deletions

diff --git a/clang/lib/Sema/Sema.cpp b/clang/lib/Sema/Sema.cpp
index 171101bb96d..c0e7572cdde 100644
--- a/clang/lib/Sema/Sema.cpp
+++ b/clang/lib/Sema/Sema.cpp
@@ -15,6 +15,7 @@
 #include "Sema.h"
 #include "TargetAttributesSema.h"
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/APFloat.h"
 #include "clang/AST/ASTConsumer.h"
 #include "clang/AST/ASTContext.h"
@@ -472,12 +473,14 @@ void Sema::ActOnEndOfTranslationUnit() {
   //   translation unit contains a file scope declaration of that
   //   identifier, with the composite type as of the end of the
   //   translation unit, with an initializer equal to 0.
-  for (unsigned i = 0, e = TentativeDefinitionList.size(); i != e; ++i) {
-    VarDecl *VD = TentativeDefinitions.lookup(TentativeDefinitionList[i]);
-
-    // If the tentative definition was completed, it will be in the list, but
-    // not the map.
-    if (VD == 0 || VD->isInvalidDecl() || !VD->isTentativeDefinition(Context))
+  llvm::SmallSet<VarDecl *, 32> Seen;
+  for (unsigned i = 0, e = TentativeDefinitions.size(); i != e; ++i) {
+    VarDecl *VD = TentativeDefinitions[i]->getActingDefinition();
+
+    // If the tentative definition was completed, getActingDefinition() returns
+    // null. If we've already seen this variable before, insert()'s second
+    // return value is false.
+    if (VD == 0 || VD->isInvalidDecl() || !Seen.insert(VD))
       continue;
 
     if (const IncompleteArrayType *ArrayT
diff --git a/clang/lib/Sema/Sema.h b/clang/lib/Sema/Sema.h
index 7f4806d3050..54d36357be2 100644
--- a/clang/lib/Sema/Sema.h
+++ b/clang/lib/Sema/Sema.h
@@ -272,14 +272,8 @@ public:
   ///     not visible.
   llvm::DenseMap<DeclarationName, NamedDecl *> LocallyScopedExternalDecls;
 
-  /// \brief The set of tentative declarations seen so far in this
-  /// translation unit for which no definition has been seen.
-  ///
-  /// The tentative declarations are indexed by the name of the
-  /// declaration, and only the most recent tentative declaration for
-  /// a given variable will be recorded here.
-  llvm::DenseMap<DeclarationName, VarDecl *> TentativeDefinitions;
-  std::vector<DeclarationName> TentativeDefinitionList;
+  /// \brief All the tentative definitions encountered in the TU.
+  std::vector<VarDecl *> TentativeDefinitions;
 
   struct DelayedDiagnostic {
     enum DDKind { Deprecation, Access };
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 398c156f9b5..a493a29a5d2 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -3570,14 +3570,6 @@ void Sema::AddInitializerToDecl(DeclPtrTy dcl, ExprArg init, bool DirectInit) {
   // Attach the initializer to the decl.
   VDecl->setInit(Context, Init);
 
-  // If the previous declaration of VDecl was a tentative definition,
-  // remove it from the set of tentative definitions.
-  if (VDecl->getPreviousDeclaration() &&
-      VDecl->getPreviousDeclaration()->isTentativeDefinition(Context)) {
-    bool Deleted = TentativeDefinitions.erase(VDecl->getDeclName());
-    assert(Deleted && "Unrecorded tentative definition?"); Deleted=Deleted;
-  }
-
   if (getLangOptions().CPlusPlus) {
     // Make sure we mark the destructor as used if necessary.
     QualType InitType = VDecl->getType();
@@ -3602,20 +3594,8 @@ void Sema::ActOnUninitializedDecl(DeclPtrTy dcl,
     QualType Type = Var->getType();
 
     // Record tentative definitions.
-    if (Var->isTentativeDefinition(Context)) {
-      std::pair<llvm::DenseMap<DeclarationName, VarDecl *>::iterator, bool>
-        InsertPair =
-           TentativeDefinitions.insert(std::make_pair(Var->getDeclName(), Var));
-
-      // Keep the latest definition in the map.  If we see 'int i; int i;' we
-      // want the second one in the map.
-      InsertPair.first->second = Var;
-
-      // However, for the list, we don't care about the order, just make sure
-      // that there are no dupes for a given declaration name.
-      if (InsertPair.second)
-        TentativeDefinitionList.push_back(Var->getDeclName());
-    }
+    if (Var->isTentativeDefinitionNow())
+      TentativeDefinitions.push_back(Var);
 
     // C++ [dcl.init.ref]p3:
     //   The initializer can be omitted for a reference only in a
@@ -3794,7 +3774,8 @@ Sema::DeclGroupPtrTy Sema::FinalizeDeclaratorGroup(Scope *S, const DeclSpec &DS,
     // storage-class specifier or with the storage-class specifier "static",
     // constitutes a tentative definition. Note: A tentative definition with
     // external linkage is valid (C99 6.2.2p5).
-    if (IDecl->isTentativeDefinition(Context) && !IDecl->isInvalidDecl()) {
+    if (IDecl->isThisDeclarationADefinition() == VarDecl::TentativeDefinition &&
+        !IDecl->isInvalidDecl()) {
       if (const IncompleteArrayType *ArrayT
           = Context.getAsIncompleteArrayType(T)) {
         if (RequireCompleteType(IDecl->getLocation(),