[turbofan] Implement the call protocol properly for direct calls.

src/compiler/js-typed-lowering.cc

Index: src/compiler/js-typed-lowering.cc
diff --git a/src/compiler/js-typed-lowering.cc b/src/compiler/js-typed-lowering.cc
index a37f818761d6c4cc97dd0207af3e5a47862c8c7e..bcc4584bba0b19a467d05fa54021e94ee9b107d4 100644
--- a/src/compiler/js-typed-lowering.cc
+++ b/src/compiler/js-typed-lowering.cc
@@ -1590,6 +1590,10 @@ Reduction JSTypedLowering::ReduceJSCallFunction(Node* node) {
         Handle<JSFunction>::cast(target_type->AsConstant()->Value());
     Handle<SharedFunctionInfo> shared(function->shared(), isolate());
 
+    // Class constructors are callable, but [[Call]] will raise an exception.
+    // See ES6 section 9.2.1 [[Call]] ( thisArgument, argumentsList).

[Michael Starzinger, 2015/11/04 13:43:14]

nit: Parenthesis look weird, can we add a trailing space before the closing one?

[Benedikt Meurer, 2015/11/04 13:51:09]

Done.

+    if (IsClassConstructor(shared->kind())) return NoChange();
+
     // Grab the context from the {function}.
     Node* context = jsgraph()->Constant(handle(function->context(), isolate()));
     NodeProperties::ReplaceContextInput(node, context);
@@ -1611,12 +1615,17 @@ Reduction JSTypedLowering::ReduceJSCallFunction(Node* node) {
     CallDescriptor::Flags flags = CallDescriptor::kNeedsFrameState;
     if (p.AllowTailCalls()) flags |= CallDescriptor::kSupportsTailCalls;
 
-    if (shared->internal_formal_parameter_count() == arity) {
+    if (shared->internal_formal_parameter_count() == arity ||
+        shared->internal_formal_parameter_count() ==
+            SharedFunctionInfo::kDontAdaptArgumentsSentinel) {
       // Patch {node} to a direct call.
+      node->InsertInput(graph()->zone(), arity + 2,
+                        jsgraph()->Int32Constant(arity));
       NodeProperties::ChangeOp(node,
                                common()->Call(Linkage::GetJSCallDescriptor(
                                    graph()->zone(), false, 1 + arity, flags)));
     } else {
+      // Patch {node} to an indirect call via the ArgumentsAdaptorTrampoline.
       Callable callable = CodeFactory::ArgumentAdaptor(isolate());
       node->InsertInput(graph()->zone(), 0,
                         jsgraph()->HeapConstant(callable.code()));