Add two new AST nodes to represent initialization of an array in terms of

initialization of each array element:

 * ArrayInitLoopExpr is a prvalue of array type with two subexpressions:
   a common expression (an OpaqueValueExpr) that represents the up-front
   computation of the source of the initialization, and a subexpression
   representing a per-element initializer
 * ArrayInitIndexExpr is a prvalue of type size_t representing the current
   position in the loop

This will be used to replace the creation of explicit index variables in lambda
capture of arrays and copy/move construction of classes with array elements,
and also C++17 structured bindings of arrays by value (which inexplicably allow
copying an array by value, unlike all of C++'s other array declarations).

No uses of these nodes are introduced by this change, however.

llvm-svn: 289413

1 files changed, 17 insertions, 0 deletions

diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index 1a07e719f12..af60a56564c 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -3221,6 +3221,9 @@ ExprResult TreeTransform<Derived>::TransformInitializer(Expr *Init,
   if (ExprWithCleanups *ExprTemp = dyn_cast<ExprWithCleanups>(Init))
     Init = ExprTemp->getSubExpr();
 
+  if (auto *AIL = dyn_cast<ArrayInitLoopExpr>(Init))
+    Init = AIL->getCommonExpr();
+
   if (MaterializeTemporaryExpr *MTE = dyn_cast<MaterializeTemporaryExpr>(Init))
     Init = MTE->GetTemporaryExpr();
 
@@ -9047,6 +9050,20 @@ TreeTransform<Derived>::TransformNoInitExpr(
 
 template<typename Derived>
 ExprResult
+TreeTransform<Derived>::TransformArrayInitLoopExpr(ArrayInitLoopExpr *E) {
+  llvm_unreachable("Unexpected ArrayInitLoopExpr outside of initializer");
+  return ExprError();
+}
+
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformArrayInitIndexExpr(ArrayInitIndexExpr *E) {
+  llvm_unreachable("Unexpected ArrayInitIndexExpr outside of initializer");
+  return ExprError();
+}
+
+template<typename Derived>
+ExprResult
 TreeTransform<Derived>::TransformImplicitValueInitExpr(
                                                      ImplicitValueInitExpr *E) {
   TemporaryBase Rebase(*this, E->getLocStart(), DeclarationName());