Support for destroying operator delete, per C++2a proposal P0722.

This feature is not (yet) approved by the C++ committee, so this is liable to
be reverted or significantly modified based on committee feedback.

No functionality change intended for existing code (a new type must be defined
in namespace std to take advantage of this feature).

llvm-svn: 315662

1 files changed, 16 insertions, 0 deletions

diff --git a/clang/lib/AST/ExprCXX.cpp b/clang/lib/AST/ExprCXX.cpp
index fe45b5e47f3..182a8b415a4 100644
--- a/clang/lib/AST/ExprCXX.cpp
+++ b/clang/lib/AST/ExprCXX.cpp
@@ -160,6 +160,22 @@ bool CXXNewExpr::shouldNullCheckAllocation(const ASTContext &Ctx) const {
 // CXXDeleteExpr
 QualType CXXDeleteExpr::getDestroyedType() const {
   const Expr *Arg = getArgument();
+
+  // For a destroying operator delete, we may have implicitly converted the
+  // pointer type to the type of the parameter of the 'operator delete'
+  // function.
+  while (auto *ICE = dyn_cast<ImplicitCastExpr>(Arg)) {
+    if (ICE->getCastKind() == CK_DerivedToBase ||
+        ICE->getCastKind() == CK_UncheckedDerivedToBase ||
+        ICE->getCastKind() == CK_NoOp) {
+      assert((ICE->getCastKind() == CK_NoOp ||
+              getOperatorDelete()->isDestroyingOperatorDelete()) &&
+             "only a destroying operator delete can have a converted arg");
+      Arg = ICE->getSubExpr();
+    } else
+      break;
+  }
+
   // The type-to-delete may not be a pointer if it's a dependent type.
   const QualType ArgType = Arg->getType();