[NFC] Refactor representation of materialized temporaries

Summary:
this patch refactor representation of materialized temporaries to prevent an issue raised by rsmith in https://reviews.llvm.org/D63640#inline-612718

Reviewers: rsmith, martong, shafik

Reviewed By: rsmith

Subscribers: thakis, sammccall, ilya-biryukov, rnkovacs, arphaman, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D69360

1 files changed, 21 insertions, 7 deletions

diff --git a/clang/lib/AST/ExprCXX.cpp b/clang/lib/AST/ExprCXX.cpp
index 904928bdf28..0fb132dbe3f 100644
--- a/clang/lib/AST/ExprCXX.cpp
+++ b/clang/lib/AST/ExprCXX.cpp
@@ -1653,7 +1653,23 @@ FunctionParmPackExpr::CreateEmpty(const ASTContext &Context,
       FunctionParmPackExpr(QualType(), nullptr, SourceLocation(), 0, nullptr);
 }
 
-void MaterializeTemporaryExpr::setExtendingDecl(const ValueDecl *ExtendedBy,
+MaterializeTemporaryExpr::MaterializeTemporaryExpr(
+    QualType T, Expr *Temporary, bool BoundToLvalueReference,
+    LifetimeExtendedTemporaryDecl *MTD)
+    : Expr(MaterializeTemporaryExprClass, T,
+           BoundToLvalueReference ? VK_LValue : VK_XValue, OK_Ordinary,
+           Temporary->isTypeDependent(), Temporary->isValueDependent(),
+           Temporary->isInstantiationDependent(),
+           Temporary->containsUnexpandedParameterPack()) {
+  if (MTD) {
+    State = MTD;
+    MTD->ExprWithTemporary = Temporary;
+    return;
+  }
+  State = Temporary;
+}
+
+void MaterializeTemporaryExpr::setExtendingDecl(ValueDecl *ExtendedBy,
                                                 unsigned ManglingNumber) {
   // We only need extra state if we have to remember more than just the Stmt.
   if (!ExtendedBy)
@@ -1661,13 +1677,11 @@ void MaterializeTemporaryExpr::setExtendingDecl(const ValueDecl *ExtendedBy,
 
   // We may need to allocate extra storage for the mangling number and the
   // extended-by ValueDecl.
-  if (!State.is<ExtraState *>()) {
-    auto *ES = new (ExtendedBy->getASTContext()) ExtraState;
-    ES->Temporary = State.get<Stmt *>();
-    State = ES;
-  }
+  if (!State.is<LifetimeExtendedTemporaryDecl *>())
+    State = LifetimeExtendedTemporaryDecl::Create(
+        cast<Expr>(State.get<Stmt *>()), ExtendedBy, ManglingNumber);
 
-  auto ES = State.get<ExtraState *>();
+  auto ES = State.get<LifetimeExtendedTemporaryDecl *>();
   ES->ExtendingDecl = ExtendedBy;
   ES->ManglingNumber = ManglingNumber;
 }