1 files changed, 47 insertions, 4 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index d0cd23e8592..c005f103a30 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -5432,6 +5432,35 @@ bool Sema::VerifyIntegerConstantExpression(const Expr *E, llvm::APSInt *Result){
   return false;
 }
 
+Sema::ExpressionEvaluationContext 
+Sema::PushExpressionEvaluationContext(ExpressionEvaluationContext NewContext) { 
+  // Introduce a new set of potentially referenced declarations to the stack.
+  if (NewContext == PotentiallyPotentiallyEvaluated)
+    PotentiallyReferencedDeclStack.push_back(PotentiallyReferencedDecls());
+  
+  std::swap(ExprEvalContext, NewContext);
+  return NewContext;
+}
+
+void 
+Sema::PopExpressionEvaluationContext(ExpressionEvaluationContext OldContext,
+                                     ExpressionEvaluationContext NewContext) {
+  ExprEvalContext = NewContext;
+
+  if (OldContext == PotentiallyPotentiallyEvaluated) {
+    // Mark any remaining declarations in the current position of the stack
+    // as "referenced". If they were not meant to be referenced, semantic
+    // analysis would have eliminated them (e.g., in ActOnCXXTypeId).
+    PotentiallyReferencedDecls RemainingDecls;
+    RemainingDecls.swap(PotentiallyReferencedDeclStack.back());
+    PotentiallyReferencedDeclStack.pop_back();
+    
+    for (PotentiallyReferencedDecls::iterator I = RemainingDecls.begin(),
+                                           IEnd = RemainingDecls.end();
+         I != IEnd; ++I)
+      MarkDeclarationReferenced(I->first, I->second);
+  }
+}
 
 /// \brief Note that the given declaration was referenced in the source code.
 ///
@@ -5456,10 +5485,24 @@ void Sema::MarkDeclarationReferenced(SourceLocation Loc, Decl *D) {
   if (CurContext->isDependentContext())
     return;
   
-  // If we are in an unevaluated operand, don't mark any definitions as used.
-  if (InUnevaluatedOperand)
-    return;
-  
+  switch (ExprEvalContext) {
+    case Unevaluated:
+      // We are in an expression that is not potentially evaluated; do nothing.
+      return;
+      
+    case PotentiallyEvaluated:
+      // We are in a potentially-evaluated expression, so this declaration is
+      // "used"; handle this below.
+      break;
+      
+    case PotentiallyPotentiallyEvaluated:
+      // We are in an expression that may be potentially evaluated; queue this
+      // declaration reference until we know whether the expression is
+      // potentially evaluated.
+      PotentiallyReferencedDeclStack.back().push_back(std::make_pair(Loc, D));
+      return;
+  }
+      
   // Note that this declaration has been used.
   if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
     if (Constructor->isImplicit() && Constructor->isDefaultConstructor()) {