[builtins] Start refactoring the Apply builtin.

src/builtins/builtins-call-gen.cc

Index: src/builtins/builtins-call-gen.cc
diff --git a/src/builtins/builtins-call-gen.cc b/src/builtins/builtins-call-gen.cc
index bd70865399b31db82451a7aa22e4fa2f9c5f16f4..65075ddca9c33422956183fed3e932ee8d3bffff 100644
--- a/src/builtins/builtins-call-gen.cc
+++ b/src/builtins/builtins-call-gen.cc
@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "src/builtins/builtins-call-gen.h"
+
+#include "src/builtins/builtins-utils-gen.h"
 #include "src/builtins/builtins.h"
 #include "src/globals.h"
 #include "src/isolate.h"
@@ -82,6 +85,10 @@ void Builtins::Generate_TailCall_ReceiverIsAny(MacroAssembler* masm) {
   Generate_Call(masm, ConvertReceiverMode::kAny, TailCallMode::kAllow);
 }
 
+void Builtins::Generate_CallVarargs(MacroAssembler* masm) {
+  Generate_Varargs(masm, masm->isolate()->builtins()->Call());
+}
+
 void Builtins::Generate_CallForwardVarargs(MacroAssembler* masm) {
   Generate_ForwardVarargs(masm, masm->isolate()->builtins()->Call());
 }
@@ -90,5 +97,119 @@ void Builtins::Generate_CallFunctionForwardVarargs(MacroAssembler* masm) {
   Generate_ForwardVarargs(masm, masm->isolate()->builtins()->CallFunction());
 }
 
+void CallOrConstructBuiltinsAssembler::CallOrConstructWithArrayLike(
+    Node* target, Node* new_target, Node* arguments_list, Node* context) {
+  Variable var_elements(this, MachineRepresentation::kTagged);
+  Variable var_length(this, MachineRepresentation::kWord32);
+  Label if_done(this), if_arguments(this), if_array(this),
+      if_holey_array(this, Label::kDeferred),
+      if_runtime(this, Label::kDeferred);
+
+  GotoIf(TaggedIsSmi(arguments_list), &if_runtime);
+  Node* arguments_list_map = LoadMap(arguments_list);
+  Node* native_context = LoadNativeContext(context);
+
+  // Check if {arguments_list} is an (unmodified) arguments object.
+  Node* sloppy_arguments_map =
+      LoadContextElement(native_context, Context::SLOPPY_ARGUMENTS_MAP_INDEX);
+  GotoIf(WordEqual(arguments_list_map, sloppy_arguments_map), &if_arguments);
+  Node* strict_arguments_map =
+      LoadContextElement(native_context, Context::STRICT_ARGUMENTS_MAP_INDEX);
+  GotoIf(WordEqual(arguments_list_map, strict_arguments_map), &if_arguments);
+
+  // Check if {arguments_list} is a fast JSArray.
+  Branch(IsJSArrayMap(arguments_list_map), &if_array, &if_runtime);
+
+  BIND(&if_array);
+  {
+    // Try to extract the elements from a JSArray object.
+    var_elements.Bind(
+        LoadObjectField(arguments_list, JSArray::kElementsOffset));
+    var_length.Bind(LoadAndUntagToWord32ObjectField(arguments_list,

[petermarshall, 2017/06/08 08:49:04]

You can use LoadJSArrayLength

[Benedikt Meurer, 2017/06/08 18:02:58]

That doesn't untag.

+                                                    JSArray::kLengthOffset));
+
+    // Holey arrays and double backing stores need special treatment.
+    Node* kind = LoadMapElementsKind(arguments_list_map);
+    STATIC_ASSERT(FAST_SMI_ELEMENTS == 0);
+    STATIC_ASSERT(FAST_HOLEY_SMI_ELEMENTS == 1);
+    STATIC_ASSERT(FAST_ELEMENTS == 2);
+    STATIC_ASSERT(FAST_HOLEY_ELEMENTS == 3);
+    GotoIf(Word32Equal(kind, Int32Constant(FAST_HOLEY_SMI_ELEMENTS)),
+           &if_holey_array);
+    GotoIf(Word32Equal(kind, Int32Constant(FAST_HOLEY_ELEMENTS)),
+           &if_holey_array);
+    Branch(Uint32LessThanOrEqual(kind, Int32Constant(FAST_HOLEY_ELEMENTS)),
+           &if_done, &if_runtime);
+  }
+
+  BIND(&if_holey_array);
+  {
+    // For holey JSArrays we need to check that the array prototype chain
+    // protector is intact and our prototype is the Array.prototype actually.
+    Node* arguments_list_prototype =

[petermarshall, 2017/06/08 08:49:04]

LoadMapPrototype =]

[Benedikt Meurer, 2017/06/08 18:02:58]

Done.

+        LoadObjectField(arguments_list_map, Map::kPrototypeOffset);
+    Node* initial_array_prototype = LoadContextElement(
+        native_context, Context::INITIAL_ARRAY_PROTOTYPE_INDEX);
+    GotoIfNot(WordEqual(arguments_list_prototype, initial_array_prototype),
+              &if_runtime);
+    Node* protector_cell = LoadRoot(Heap::kArrayProtectorRootIndex);

[petermarshall, 2017/06/08 08:49:04]

Might be worth adding 
DCHECK(isolate()->heap()->array_protector()->IsPropertyCell());
here

[Benedikt Meurer, 2017/06/08 18:02:58]

Done.

+    Branch(
+        WordEqual(LoadObjectField(protector_cell, PropertyCell::kValueOffset),
+                  SmiConstant(Smi::FromInt(Isolate::kProtectorValid))),
+        &if_done, &if_runtime);
+  }
+
+  BIND(&if_arguments);
+  {
+    // Try to extract the elements from an JSArgumentsObject.
+    Node* length =
+        LoadObjectField(arguments_list, JSArgumentsObject::kLengthOffset);
+    Node* elements =
+        LoadObjectField(arguments_list, JSArgumentsObject::kElementsOffset);
+    Node* elements_length =
+        LoadObjectField(elements, FixedArray::kLengthOffset);
+    GotoIfNot(WordEqual(length, elements_length), &if_runtime);
+    var_elements.Bind(elements);
+    var_length.Bind(SmiToWord32(length));
+    Goto(&if_done);
+  }
+
+  BIND(&if_runtime);
+  {
+    // Ask the runtime to create the list (actually a FixedArray).
+    Node* elements =
+        CallRuntime(Runtime::kCreateListFromArrayLike, context, arguments_list);
+    var_elements.Bind(elements);
+    var_length.Bind(
+        LoadAndUntagToWord32ObjectField(elements, FixedArray::kLengthOffset));
+    Goto(&if_done);
+  }
+
+  // Tail call to the appropriate builtin (depending on whether we have
+  // a {new_target} passed).
+  BIND(&if_done);
+  {
+    Node* elements = var_elements.value();
+    Node* length = var_length.value();
+    if (new_target == nullptr) {
+      Callable callable = CodeFactory::CallVarargs(isolate());
+      TailCallStub(callable, context, target, Int32Constant(0), elements,
+                   length);
+    } else {
+      Callable callable = CodeFactory::ConstructVarargs(isolate());
+      TailCallStub(callable, context, target, new_target, Int32Constant(0),
+                   elements, length);
+    }
+  }
+}
+
+TF_BUILTIN(CallWithArrayLike, CallOrConstructBuiltinsAssembler) {
+  Node* target = Parameter(CallWithArrayLikeDescriptor::kTarget);
+  Node* new_target = nullptr;
+  Node* arguments_list = Parameter(CallWithArrayLikeDescriptor::kArgumentsList);
+  Node* context = Parameter(CallWithArrayLikeDescriptor::kContext);
+  CallOrConstructWithArrayLike(target, new_target, arguments_list, context);
+}
+
 }  // namespace internal
 }  // namespace v8