[AST] Store the expressions in ParenListExpr in a trailing array

Use the newly available space in the bit-fields of Stmt
and store the expressions in a trailing array. This saves
2 pointer per ParenListExpr.

Differential Revision: https://reviews.llvm.org/D54675

Reviewed By: rjmccall

llvm-svn: 347320

2 files changed, 36 insertions, 15 deletions

diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index a8808185a1e..31607dcf446 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -6409,8 +6409,8 @@ ExpectedStmt ASTNodeImporter::VisitParenListExpr(ParenListExpr *E) {
   if (!ToRParenLocOrErr)
     return ToRParenLocOrErr.takeError();
 
-  return new (Importer.getToContext()) ParenListExpr(
-      Importer.getToContext(), *ToLParenLocOrErr, ToExprs, *ToRParenLocOrErr);
+  return ParenListExpr::Create(Importer.getToContext(), *ToLParenLocOrErr,
+                               ToExprs, *ToRParenLocOrErr);
 }
 
 ExpectedStmt ASTNodeImporter::VisitStmtExpr(StmtExpr *E) {
diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
index 2e26500862a..ec6f084aedf 100644
--- a/clang/lib/AST/Expr.cpp
+++ b/clang/lib/AST/Expr.cpp
@@ -4004,27 +4004,48 @@ SourceLocation DesignatedInitUpdateExpr::getEndLoc() const {
   return getBase()->getEndLoc();
 }
 
-ParenListExpr::ParenListExpr(const ASTContext& C, SourceLocation lparenloc,
-                             ArrayRef<Expr*> exprs,
-                             SourceLocation rparenloc)
-  : Expr(ParenListExprClass, QualType(), VK_RValue, OK_Ordinary,
-         false, false, false, false),
-    NumExprs(exprs.size()), LParenLoc(lparenloc), RParenLoc(rparenloc) {
-  Exprs = new (C) Stmt*[exprs.size()];
-  for (unsigned i = 0; i != exprs.size(); ++i) {
-    if (exprs[i]->isTypeDependent())
+ParenListExpr::ParenListExpr(SourceLocation LParenLoc, ArrayRef<Expr *> Exprs,
+                             SourceLocation RParenLoc)
+    : Expr(ParenListExprClass, QualType(), VK_RValue, OK_Ordinary, false, false,
+           false, false),
+      LParenLoc(LParenLoc), RParenLoc(RParenLoc) {
+  ParenListExprBits.NumExprs = Exprs.size();
+
+  for (unsigned I = 0, N = Exprs.size(); I != N; ++I) {
+    if (Exprs[I]->isTypeDependent())
       ExprBits.TypeDependent = true;
-    if (exprs[i]->isValueDependent())
+    if (Exprs[I]->isValueDependent())
       ExprBits.ValueDependent = true;
-    if (exprs[i]->isInstantiationDependent())
+    if (Exprs[I]->isInstantiationDependent())
       ExprBits.InstantiationDependent = true;
-    if (exprs[i]->containsUnexpandedParameterPack())
+    if (Exprs[I]->containsUnexpandedParameterPack())
       ExprBits.ContainsUnexpandedParameterPack = true;
 
-    Exprs[i] = exprs[i];
+    getTrailingObjects<Stmt *>()[I] = Exprs[I];
   }
 }
 
+ParenListExpr::ParenListExpr(EmptyShell Empty, unsigned NumExprs)
+    : Expr(ParenListExprClass, Empty) {
+  ParenListExprBits.NumExprs = NumExprs;
+}
+
+ParenListExpr *ParenListExpr::Create(const ASTContext &Ctx,
+                                     SourceLocation LParenLoc,
+                                     ArrayRef<Expr *> Exprs,
+                                     SourceLocation RParenLoc) {
+  void *Mem = Ctx.Allocate(totalSizeToAlloc<Stmt *>(Exprs.size()),
+                           alignof(ParenListExpr));
+  return new (Mem) ParenListExpr(LParenLoc, Exprs, RParenLoc);
+}
+
+ParenListExpr *ParenListExpr::CreateEmpty(const ASTContext &Ctx,
+                                          unsigned NumExprs) {
+  void *Mem =
+      Ctx.Allocate(totalSizeToAlloc<Stmt *>(NumExprs), alignof(ParenListExpr));
+  return new (Mem) ParenListExpr(EmptyShell(), NumExprs);
+}
+
 const OpaqueValueExpr *OpaqueValueExpr::findInCopyConstruct(const Expr *e) {
   if (const ExprWithCleanups *ewc = dyn_cast<ExprWithCleanups>(e))
     e = ewc->getSubExpr();