[AST] Only store data for the NRVO candidate in ReturnStmt if needed

Only store the NRVO candidate if needed in ReturnStmt.
A good chuck of all of the ReturnStmt have no NRVO candidate
(more than half when parsing all of Boost). For all of them
this saves one pointer. This has no impact on children().

Differential Revision: https://reviews.llvm.org/D53716

Reviewed By: rsmith

llvm-svn: 345605

1 files changed, 26 insertions, 4 deletions

diff --git a/clang/lib/AST/Stmt.cpp b/clang/lib/AST/Stmt.cpp
index 81a2c50d769..bb8e424c6e5 100644
--- a/clang/lib/AST/Stmt.cpp
+++ b/clang/lib/AST/Stmt.cpp
@@ -1042,11 +1042,33 @@ LabelDecl *IndirectGotoStmt::getConstantTarget() {
 }
 
 // ReturnStmt
-const Expr* ReturnStmt::getRetValue() const {
-  return cast_or_null<Expr>(RetExpr);
+ReturnStmt::ReturnStmt(SourceLocation RL, Expr *E, const VarDecl *NRVOCandidate)
+    : Stmt(ReturnStmtClass), RetExpr(E) {
+  bool HasNRVOCandidate = NRVOCandidate != nullptr;
+  ReturnStmtBits.HasNRVOCandidate = HasNRVOCandidate;
+  if (HasNRVOCandidate)
+    setNRVOCandidate(NRVOCandidate);
+  setReturnLoc(RL);
 }
-Expr* ReturnStmt::getRetValue() {
-  return cast_or_null<Expr>(RetExpr);
+
+ReturnStmt::ReturnStmt(EmptyShell Empty, bool HasNRVOCandidate)
+    : Stmt(ReturnStmtClass, Empty) {
+  ReturnStmtBits.HasNRVOCandidate = HasNRVOCandidate;
+}
+
+ReturnStmt *ReturnStmt::Create(const ASTContext &Ctx, SourceLocation RL,
+                               Expr *E, const VarDecl *NRVOCandidate) {
+  bool HasNRVOCandidate = NRVOCandidate != nullptr;
+  void *Mem = Ctx.Allocate(totalSizeToAlloc<const VarDecl *>(HasNRVOCandidate),
+                           alignof(ReturnStmt));
+  return new (Mem) ReturnStmt(RL, E, NRVOCandidate);
+}
+
+ReturnStmt *ReturnStmt::CreateEmpty(const ASTContext &Ctx,
+                                    bool HasNRVOCandidate) {
+  void *Mem = Ctx.Allocate(totalSizeToAlloc<const VarDecl *>(HasNRVOCandidate),
+                           alignof(ReturnStmt));
+  return new (Mem) ReturnStmt(EmptyShell(), HasNRVOCandidate);
 }
 
 // CaseStmt