1 files changed, 31 insertions, 19 deletions

diff --git a/clang/lib/Sema/Sema.cpp b/clang/lib/Sema/Sema.cpp
index d0ed6bf75f3..c61e2fdcab2 100644
--- a/clang/lib/Sema/Sema.cpp
+++ b/clang/lib/Sema/Sema.cpp
@@ -162,7 +162,7 @@ Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
       ExpressionEvaluationContext::PotentiallyEvaluated, 0, CleanupInfo{},
       nullptr, false);
 
-  FunctionScopes.push_back(new FunctionScopeInfo(Diags));
+  PreallocatedFunctionScope.reset(new FunctionScopeInfo(Diags));
 
   // Initilization of data sharing attributes stack for OpenMP
   InitDataSharingAttributesStack();
@@ -332,11 +332,11 @@ void Sema::Initialize() {
 
 Sema::~Sema() {
   if (VisContext) FreeVisContext();
+
   // Kill all the active scopes.
-  for (unsigned I = 1, E = FunctionScopes.size(); I != E; ++I)
-    delete FunctionScopes[I];
-  if (FunctionScopes.size() == 1)
-    delete FunctionScopes[0];
+  for (sema::FunctionScopeInfo *FSI : FunctionScopes)
+    if (FSI != PreallocatedFunctionScope.get())
+      delete FSI;
 
   // Tell the SemaConsumer to forget about us; we're going out of scope.
   if (SemaConsumer *SC = dyn_cast<SemaConsumer>(&Consumer))
@@ -1340,17 +1340,13 @@ Scope *Sema::getScopeForContext(DeclContext *Ctx) {
 
 /// \brief Enter a new function scope
 void Sema::PushFunctionScope() {
-  if (FunctionScopes.size() == 1) {
-    // Use the "top" function scope rather than having to allocate
-    // memory for a new scope.
-    FunctionScopes.back()->Clear();
-    FunctionScopes.push_back(FunctionScopes.back());
-    if (LangOpts.OpenMP)
-      pushOpenMPFunctionRegion();
-    return;
+  if (FunctionScopes.empty()) {
+    // Use PreallocatedFunctionScope to avoid allocating memory when possible.
+    PreallocatedFunctionScope->Clear();
+    FunctionScopes.push_back(PreallocatedFunctionScope.get());
+  } else {
+    FunctionScopes.push_back(new FunctionScopeInfo(getDiagnostics()));
   }
-
-  FunctionScopes.push_back(new FunctionScopeInfo(getDiagnostics()));
   if (LangOpts.OpenMP)
     pushOpenMPFunctionRegion();
 }
@@ -1370,15 +1366,15 @@ void Sema::RecordParsingTemplateParameterDepth(unsigned Depth) {
   if (LambdaScopeInfo *const LSI = getCurLambda()) {
     LSI->AutoTemplateParameterDepth = Depth;
     return;
-  } 
-  llvm_unreachable( 
+  }
+  llvm_unreachable(
       "Remove assertion if intentionally called in a non-lambda context.");
 }
 
 void Sema::PopFunctionScopeInfo(const AnalysisBasedWarnings::Policy *WP,
                                 const Decl *D, const BlockExpr *blkExpr) {
-  FunctionScopeInfo *Scope = FunctionScopes.pop_back_val();
   assert(!FunctionScopes.empty() && "mismatched push/pop!");
+  FunctionScopeInfo *Scope = FunctionScopes.pop_back_val();
 
   if (LangOpts.OpenMP)
     popOpenMPFunctionRegion(Scope);
@@ -1390,7 +1386,8 @@ void Sema::PopFunctionScopeInfo(const AnalysisBasedWarnings::Policy *WP,
     for (const auto &PUD : Scope->PossiblyUnreachableDiags)
       Diag(PUD.Loc, PUD.PD);
 
-  if (FunctionScopes.back() != Scope)
+  // Delete the scope unless its our preallocated scope.
+  if (Scope != PreallocatedFunctionScope.get())
     delete Scope;
 }
 
@@ -1411,6 +1408,21 @@ bool Sema::hasAnyUnrecoverableErrorsInThisFunction() const {
   return getCurFunction()->ErrorTrap.hasUnrecoverableErrorOccurred();
 }
 
+void Sema::setFunctionHasBranchIntoScope() {
+  if (!FunctionScopes.empty())
+    FunctionScopes.back()->setHasBranchIntoScope();
+}
+
+void Sema::setFunctionHasBranchProtectedScope() {
+  if (!FunctionScopes.empty())
+    FunctionScopes.back()->setHasBranchProtectedScope();
+}
+
+void Sema::setFunctionHasIndirectGoto() {
+  if (!FunctionScopes.empty())
+    FunctionScopes.back()->setHasIndirectGoto();
+}
+
 BlockScopeInfo *Sema::getCurBlock() {
   if (FunctionScopes.empty())
     return nullptr;