Define and implement CXXNoexceptExpr. Create it in Sema.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@113623 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index 7c9baa7..8e29caa 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -3114,15 +3114,21 @@
   return CE;
 }
 
-ExprResult Sema::ActOnNoexceptExpr(SourceLocation KeyLoc, SourceLocation LParen,
-                                   Expr *Operand, SourceLocation RParen) {
+ExprResult Sema::BuildCXXNoexceptExpr(SourceLocation KeyLoc, Expr *Operand,
+                                      SourceLocation RParen) {
   // C++ [expr.unary.noexcept]p1:
   //   The noexcept operator determines whether the evaluation of its operand,
   //   which is an unevaluated operand, can throw an exception.
   ExprEvalContexts.back().Context = Unevaluated;
 
-//return Owned(new (Context) CXXNoexceptExpr(KeyLoc, LParen, Operand, RParen));
-  return ExprError();
+  return Owned(new (Context) CXXNoexceptExpr(Context.BoolTy, Operand,
+                                             Operand->CanThrow(Context),
+                                             KeyLoc, RParen));
+}
+
+ExprResult Sema::ActOnNoexceptExpr(SourceLocation KeyLoc, SourceLocation,
+                                   Expr *Operand, SourceLocation RParen) {
+  return BuildCXXNoexceptExpr(KeyLoc, Operand, RParen);
 }
 
 ExprResult Sema::ActOnFinishFullExpr(Expr *FullExpr) {
diff --git a/lib/Sema/TreeTransform.h b/lib/Sema/TreeTransform.h
index 7f3450b..765ce0f 100644
--- a/lib/Sema/TreeTransform.h
+++ b/lib/Sema/TreeTransform.h
@@ -1773,6 +1773,14 @@
                                             R, TemplateArgs);
   }
 
+  /// \brief Build a new noexcept expression.
+  ///
+  /// By default, performs semantic analysis to build the new expression.
+  /// Subclasses may override this routine to provide different behavior.
+  ExprResult RebuildCXXNoexceptExpr(SourceRange Range, Expr *Arg) {
+    return SemaRef.BuildCXXNoexceptExpr(Range.getBegin(), Arg, Range.getEnd());
+  }
+
   /// \brief Build a new Objective-C @encode expression.
   ///
   /// By default, performs semantic analysis to build the new expression.
@@ -5977,6 +5985,19 @@
 
 template<typename Derived>
 ExprResult
+TreeTransform<Derived>::TransformCXXNoexceptExpr(CXXNoexceptExpr *E) {
+  ExprResult SubExpr = getDerived().TransformExpr(E->getOperand());
+  if (SubExpr.isInvalid())
+    return ExprError();
+
+  if (!getDerived().AlwaysRebuild() && SubExpr.get() == E->getOperand())
+    return SemaRef.Owned(E->Retain());
+
+  return getDerived().RebuildCXXNoexceptExpr(E->getSourceRange(),SubExpr.get());
+}
+
+template<typename Derived>
+ExprResult
 TreeTransform<Derived>::TransformObjCStringLiteral(ObjCStringLiteral *E) {
   return SemaRef.Owned(E->Retain());
 }