[ignition] Simplify ForInPrepare by directly using TF builtin

Change-Id: I91bedd8d30e32f270fb528d0d8bbfed45074878f
Reviewed-on: https://chromium-review.googlesource.com/440065Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43103}

BUILD.gn

@@ -1000,6 +1000,7 @@ v8_source_set("v8_base") {
     "src/builtins/builtins-math.cc",
     "src/builtins/builtins-number.cc",
     "src/builtins/builtins-object.cc",
+    "src/builtins/builtins-object.h",
     "src/builtins/builtins-promise.cc",
     "src/builtins/builtins-promise.h",
     "src/builtins/builtins-proxy.cc",

src/builtins/builtins-object.cc

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "src/builtins/builtins-object.h"
 #include "src/builtins/builtins-utils.h"
 #include "src/builtins/builtins.h"
 #include "src/code-factory.h"
@@ -11,16 +12,27 @@
 namespace v8 {
 namespace internal {
 
-class ObjectBuiltinsAssembler : public CodeStubAssembler {
- public:
-  explicit ObjectBuiltinsAssembler(compiler::CodeAssemblerState* state)
-      : CodeStubAssembler(state) {}
+typedef compiler::Node Node;
 
- protected:
-  void IsString(Node* object, Label* if_string, Label* if_notstring);
-  void ReturnToStringFormat(Node* context, Node* string);
-};
+std::tuple<Node*, Node*, Node*> ObjectBuiltinsAssembler::EmitForInPrepare(
+    Node* object, Node* context, Label* call_runtime,
+    Label* nothing_to_iterate) {
+  Label use_cache(this);
+  CSA_ASSERT(this, IsJSReceiver(object));
 
+  CheckEnumCache(object, &use_cache, call_runtime);
+  Bind(&use_cache);
+  Node* map = LoadMap(object);
+  Node* enum_length = EnumLength(map);
+  GotoIf(WordEqual(enum_length, SmiConstant(0)), nothing_to_iterate);
+  Node* descriptors = LoadMapDescriptors(map);
+  Node* cache_offset =
+      LoadObjectField(descriptors, DescriptorArray::kEnumCacheOffset);
+  Node* enum_cache = LoadObjectField(
+      cache_offset, DescriptorArray::kEnumCacheBridgeCacheOffset);
+
+  return std::make_tuple(map, enum_cache, enum_length);
+}
 // -----------------------------------------------------------------------------
 // ES6 section 19.1 Object Objects
 
@@ -931,28 +943,26 @@ TF_BUILTIN(ForInNext, ObjectBuiltinsAssembler) {
 TF_BUILTIN(ForInPrepare, ObjectBuiltinsAssembler) {
   typedef ForInPrepareDescriptor Descriptor;
 
-  Label use_cache(this), nothing_to_iterate(this), call_runtime(this);
+  Label call_runtime(this), nothing_to_iterate(this);
   Node* object = Parameter(Descriptor::kObject);
   Node* context = Parameter(Descriptor::kContext);
 
-  CheckEnumCache(object, &use_cache, &call_runtime);
-  Bind(&use_cache);
-  Node* map = LoadMap(object);
-  Node* enum_length = EnumLength(map);
-  GotoIf(WordEqual(enum_length, SmiConstant(0)), &nothing_to_iterate);
-  Node* descriptors = LoadMapDescriptors(map);
-  Node* cache_offset =
-      LoadObjectField(descriptors, DescriptorArray::kEnumCacheOffset);
-  Node* enum_cache = LoadObjectField(
-      cache_offset, DescriptorArray::kEnumCacheBridgeCacheOffset);
-  Return(map, enum_cache, enum_length);
+  Node* cache_type;
+  Node* cache_array;
+  Node* cache_length;
+  std::tie(cache_type, cache_array, cache_length) =
+      EmitForInPrepare(object, context, &call_runtime, &nothing_to_iterate);
 
-  Bind(&nothing_to_iterate);
-  Node* zero = SmiConstant(0);
-  Return(zero, zero, zero);
+  Return(cache_type, cache_array, cache_length);
 
   Bind(&call_runtime);
   TailCallRuntime(Runtime::kForInPrepare, context, object);
+
+  Bind(&nothing_to_iterate);
+  {
+    Node* zero = SmiConstant(0);
+    Return(zero, zero, zero);
+  }
 }
 
 TF_BUILTIN(InstanceOf, ObjectBuiltinsAssembler) {

src/builtins/builtins-object.h

+
+// Copyright 2017 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/code-stub-assembler.h"
+
+namespace v8 {
+namespace internal {
+
+class ObjectBuiltinsAssembler : public CodeStubAssembler {
+ public:
+  explicit ObjectBuiltinsAssembler(compiler::CodeAssemblerState* state)
+      : CodeStubAssembler(state) {}
+
+  std::tuple<Node*, Node*, Node*> EmitForInPrepare(Node* object, Node* context,
+                                                   Label* call_runtime,
+                                                   Label* nothing_to_iterate);
+
+ protected:
+  void IsString(Node* object, Label* if_string, Label* if_notstring);
+  void ReturnToStringFormat(Node* context, Node* string);
+};
+
+}  // namespace internal
+}  // namespace v8

src/interpreter/interpreter.cc

@@ -10,6 +10,7 @@
 #include "src/ast/prettyprinter.h"
 #include "src/builtins/builtins-arguments.h"
 #include "src/builtins/builtins-constructor.h"
+#include "src/builtins/builtins-object.h"
 #include "src/code-factory.h"
 #include "src/compilation-info.h"
 #include "src/compiler.h"
@@ -3088,68 +3089,42 @@ void Interpreter::BuildForInPrepareResult(Node* output_register,
 // |cache_info_triple + 2|, with the registers holding cache_type, cache_array,
 // and cache_length respectively.
 void Interpreter::DoForInPrepare(InterpreterAssembler* assembler) {
-  Node* object_reg = __ BytecodeOperandReg(0);
-  Node* receiver = __ LoadRegister(object_reg);
+  Node* object_register = __ BytecodeOperandReg(0);
+  Node* output_register = __ BytecodeOperandReg(1);
+  Node* receiver = __ LoadRegister(object_register);
   Node* context = __ GetContext();
-  Node* const zero_smi = __ SmiConstant(Smi::kZero);
 
-  Label nothing_to_iterate(assembler, Label::kDeferred),
-      use_enum_cache(assembler), use_runtime(assembler, Label::kDeferred);
+  Node* cache_type;
+  Node* cache_array;
+  Node* cache_length;
+  Label call_runtime(assembler, Label::kDeferred),
+      nothing_to_iterate(assembler, Label::kDeferred);
 
-  if (FLAG_debug_code) {
-    Label already_receiver(assembler), abort(assembler);
-    Node* instance_type = __ LoadInstanceType(receiver);
-    __ Branch(__ IsJSReceiverInstanceType(instance_type), &already_receiver,
-              &abort);
-    __ Bind(&abort);
-    {
-      __ Abort(kExpectedJSReceiver);
-      // TODO(klaasb) remove this unreachable Goto once Abort ends the block
-      __ Goto(&already_receiver);
-    }
-    __ Bind(&already_receiver);
-  }
+  ObjectBuiltinsAssembler object_assembler(assembler->state());
+  std::tie(cache_type, cache_array, cache_length) =
+      object_assembler.EmitForInPrepare(receiver, context, &call_runtime,
+                                        &nothing_to_iterate);
 
-  __ CheckEnumCache(receiver, &use_enum_cache, &use_runtime);
-
-  __ Bind(&use_enum_cache);
-  {
-    // The enum cache is valid.  Load the map of the object being
-    // iterated over and use the cache for the iteration.
-    Node* cache_type = __ LoadMap(receiver);
-    Node* cache_length = __ EnumLength(cache_type);
-    __ GotoIf(assembler->WordEqual(cache_length, zero_smi),
-              &nothing_to_iterate);
-    Node* descriptors = __ LoadMapDescriptors(cache_type);
-    Node* cache_offset =
-        __ LoadObjectField(descriptors, DescriptorArray::kEnumCacheOffset);
-    Node* cache_array = __ LoadObjectField(
-        cache_offset, DescriptorArray::kEnumCacheBridgeCacheOffset);
-    Node* output_register = __ BytecodeOperandReg(1);
-    BuildForInPrepareResult(output_register, cache_type, cache_array,
-                            cache_length, assembler);
-    __ Dispatch();
-  }
+  BuildForInPrepareResult(output_register, cache_type, cache_array,
+                          cache_length, assembler);
+  __ Dispatch();
 
-  __ Bind(&use_runtime);
+  __ Bind(&call_runtime);
   {
     Node* result_triple =
         __ CallRuntime(Runtime::kForInPrepare, context, receiver);
     Node* cache_type = __ Projection(0, result_triple);
     Node* cache_array = __ Projection(1, result_triple);
     Node* cache_length = __ Projection(2, result_triple);
-    Node* output_register = __ BytecodeOperandReg(1);
     BuildForInPrepareResult(output_register, cache_type, cache_array,
                             cache_length, assembler);
     __ Dispatch();
   }
-
   __ Bind(&nothing_to_iterate);
   {
     // Receiver is null or undefined or descriptors are zero length.
-    Node* output_register = __ BytecodeOperandReg(1);
-    BuildForInPrepareResult(output_register, zero_smi, zero_smi, zero_smi,
-                            assembler);
+    Node* zero = __ SmiConstant(0);
+    BuildForInPrepareResult(output_register, zero, zero, zero, assembler);
     __ Dispatch();
   }
 }

src/v8.gyp

@@ -504,6 +504,7 @@
         'builtins/builtins-math.cc',
         'builtins/builtins-number.cc',
         'builtins/builtins-object.cc',
+        'builtins/builtins-object.h',
         'builtins/builtins-promise.cc',
         'builtins/builtins-promise.h',
         'builtins/builtins-proxy.cc',