[turbofan]: Integrate basic type feedback for property accesses.

src/compiler/js-type-feedback.cc

+// Copyright 2015 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/compiler/js-type-feedback.h"
+
+#include "src/property-details.h"
+
+#include "src/accessors.h"
+#include "src/ast.h"
+#include "src/type-info.h"
+
+#include "src/compiler/common-operator.h"
+#include "src/compiler/node-aux-data.h"
+#include "src/compiler/simplified-operator.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+enum LoadOrStore { LOAD, STORE };
+
+JSTypeFeedbackTable::JSTypeFeedbackTable(Zone* zone)
+    : map_(TypeFeedbackIdMap::key_compare(),
+           TypeFeedbackIdMap::allocator_type(zone)) {}
+
+
+Node* JSTypeFeedbackTable::Record(Node* node, TypeFeedbackId id) {
+  map_.insert(std::make_pair(node->id(), id));
+  return node;
+}
+
+
+Reduction JSTypeFeedbackSpecializer::Reduce(Node* node) {
+  switch (node->opcode()) {
+    case IrOpcode::kJSLoadProperty:
+      return ReduceJSLoadProperty(node);
+    case IrOpcode::kJSLoadNamed:
+      return ReduceJSLoadNamed(node);
+    case IrOpcode::kJSStoreNamed:
+      return ReduceJSStoreNamed(node);
+    case IrOpcode::kJSStoreProperty:
+      return ReduceJSStoreProperty(node);
+    default:
+      break;
+  }
+  return NoChange();
+}
+
+
+static bool GetInObjectFieldAccess(LoadOrStore mode, Handle<Map> map,
+                                   Handle<Name> name, FieldAccess* access) {
+  access->base_is_tagged = kTaggedBase;
+  access->offset = -1;
+  access->name = name;
+  access->type = Type::Any();
+  access->machine_type = kMachAnyTagged;
+
+  // Check for properties that have accessors but are JSObject fields.
+  if (Accessors::IsJSObjectFieldAccessor(map, name, &access->offset)) {
+    // TODO(turbofan): fill in types for special JSObject field accesses.
+    return true;
+  }
+
+  // Check if the map is a dictionary.
+  if (map->is_dictionary_map()) return false;
+
+  // Search the descriptor array.
+  DescriptorArray* descriptors = map->instance_descriptors();
+  int number = descriptors->SearchWithCache(*name, *map);
+  if (number == DescriptorArray::kNotFound) return false;
+  PropertyDetails property_details = descriptors->GetDetails(number);
+
+  bool is_smi = property_details.representation().IsSmi();
+  bool is_double = property_details.representation().IsDouble();
+
+  if (mode == STORE) {
+    if (property_details.IsReadOnly()) return false;
+    if (is_smi) {
+      // TODO(turbofan): SMI stores.
+      return false;
+    }
+    if (is_double) {
+      // TODO(turbofan): double stores.
+      return false;
+    }
+    if (property_details.cell_type() == PropertyCellType::kConstant) {

[Toon Verwaest, 2015/03/24 09:42:39]

This is not how constants are encoded. PropertyDetails have 3 partially distinct
encodings. Dictionary, global, and fast-mode objects. Dictionary and global are
mostly the same, minus that global also has PropertyCellType. Here we only care
about fast-mode objects though. For now you probably want to disallow everything
that's property_details.type() != DATA, which includes DATA_CONSTANT, and both
kinds of accessors.

[titzer, 2015/03/24 10:49:31]

So the condition should be "property_details.type() != DATA"?

[Toon Verwaest, 2015/03/24 12:56:12]

indeed

[titzer, 2015/03/24 14:52:06]

Done.

+      // TODO(turbofan): constant stores.
+      return false;
+    }
+  } else {
+    // Check property details for loads.
+    if (property_details.cell_type() == PropertyCellType::kConstant) {
+      // TODO(turbofan): constants using code dependencies.

[Toon Verwaest, 2015/03/24 09:42:39]

Fast-mode-map-based constants don't use code dependencies. The map will change.

[titzer, 2015/03/24 10:49:32]

So I can just remove this condition?

The actual threading through of what constant to load needs to be thought out
into an abstractification.

[Toon Verwaest, 2015/03/24 12:56:12]

Indeed. This condition makes no sense. You'll again need to do if
(property_details.type() != DATA) return false;

[titzer, 2015/03/24 14:52:06]

Done.

+      return false;
+    }
+    if (is_smi) {
+      access->type = Type::SignedSmall();
+      access->machine_type = static_cast<MachineType>(kTypeInt32 | kRepTagged);
+    }
+    if (is_double) {
+      access->type = Type::Number();
+      access->machine_type = kMachFloat64;
+    }
+  }
+
+  int index = map->instance_descriptors()->GetFieldIndex(number);
+  FieldIndex field_index = FieldIndex::ForPropertyIndex(*map, index, is_double);
+
+  if (field_index.is_inobject()) {
+    access->offset = field_index.offset();
+    return true;
+  }
+
+  // TODO(turbofan): handle out of object properties.
+  return false;
+}
+
+
+Reduction JSTypeFeedbackSpecializer::ReduceJSLoadNamed(Node* node) {
+  DCHECK(node->opcode() == IrOpcode::kJSLoadNamed);
+  TypeFeedbackId id = js_type_feedback_->find(node);
+  if (id.IsNone() || oracle()->LoadIsUninitialized(id)) return NoChange();
+
+  const LoadNamedParameters& p = LoadNamedParametersOf(node->op());
+  SmallMapList maps;
+  Handle<Name> name = p.name().handle();
+  Node* receiver = node->InputAt(0);
+  Node* effect = NodeProperties::GetEffectInput(node);
+  GatherReceiverTypes(receiver, effect, id, name, &maps);
+
+  if (maps.length() != 1) return NoChange();  // TODO(turbofan): polymorphism
+
+  Handle<Map> map = maps.first();
+  FieldAccess field_access;
+  if (!GetInObjectFieldAccess(LOAD, map, name, &field_access)) {
+    return NoChange();
+  }
+
+  Node* control = NodeProperties::GetControlInput(node);
+  Node* check_success;
+  Node* check_failed;
+  BuildMapCheck(receiver, map, true, effect, control, &check_success,
+                &check_failed);
+
+  // Build the actual load.
+  Node* load = graph()->NewNode(simplified()->LoadField(field_access), receiver,
+                                effect, check_success);
+
+  // TODO(turbofan): handle slow case instead of deoptimizing.
+  // TODO(titzer): frame state should be from before the load.
+  Node* frame_state = NodeProperties::GetFrameStateInput(node, 0);
+  Node* deopt = graph()->NewNode(common()->Deoptimize(), frame_state, effect,
+                                 check_failed);
+  NodeProperties::MergeControlToEnd(graph(), common(), deopt);
+  NodeProperties::ReplaceWithValue(node, load, load, check_success);
+  return Replace(load);
+}
+
+
+Reduction JSTypeFeedbackSpecializer::ReduceJSLoadProperty(Node* node) {
+  return NoChange();
+}
+
+
+Reduction JSTypeFeedbackSpecializer::ReduceJSStoreNamed(Node* node) {
+  DCHECK(node->opcode() == IrOpcode::kJSStoreNamed);
+  TypeFeedbackId id = js_type_feedback_->find(node);
+  if (id.IsNone() || oracle()->StoreIsUninitialized(id)) return NoChange();
+
+  const StoreNamedParameters& p = StoreNamedParametersOf(node->op());
+  SmallMapList maps;
+  Handle<Name> name = p.name().handle();
+  Node* receiver = node->InputAt(0);
+  Node* effect = NodeProperties::GetEffectInput(node);
+  GatherReceiverTypes(receiver, effect, id, name, &maps);
+
+  if (maps.length() != 1) return NoChange();  // TODO(turbofan): polymorphism
+
+  Handle<Map> map = maps.first();
+  FieldAccess field_access;
+  if (!GetInObjectFieldAccess(STORE, map, name, &field_access)) {
+    return NoChange();
+  }
+
+  Node* control = NodeProperties::GetControlInput(node);
+  Node* check_success;
+  Node* check_failed;
+  BuildMapCheck(receiver, map, true, effect, control, &check_success,
+                &check_failed);
+
+  // Build the actual load.
+  Node* value = node->InputAt(1);
+  Node* store = graph()->NewNode(simplified()->StoreField(field_access),
+                                 receiver, value, effect, check_success);
+
+  // TODO(turbofan): handle slow case instead of deoptimizing.
+  // TODO(titzer): frame state should be from before the store.
+  Node* frame_state = NodeProperties::GetFrameStateInput(node, 0);
+  Node* deopt = graph()->NewNode(common()->Deoptimize(), frame_state, effect,
+                                 check_failed);
+  NodeProperties::MergeControlToEnd(graph(), common(), deopt);
+  NodeProperties::ReplaceWithValue(node, store, store, check_success);
+  return Replace(store);
+}
+
+
+Reduction JSTypeFeedbackSpecializer::ReduceJSStoreProperty(Node* node) {
+  return NoChange();
+}
+
+
+void JSTypeFeedbackSpecializer::BuildMapCheck(Node* receiver, Handle<Map> map,
+                                              bool smi_check, Node* effect,
+                                              Node* control, Node** success,
+                                              Node** fail) {
+  Node* if_smi = nullptr;
+  if (smi_check) {
+    Node* branch_smi = graph()->NewNode(
+        common()->Branch(BranchHint::kFalse),
+        graph()->NewNode(simplified()->ObjectIsSmi(), receiver), control);
+    if_smi = graph()->NewNode(common()->IfTrue(), branch_smi);
+    control = graph()->NewNode(common()->IfFalse(), branch_smi);
+  }
+
+  FieldAccess map_access = {kTaggedBase, JSObject::kMapOffset,

[Michael Starzinger, 2015/03/24 09:25:29]

Can we use AccessBuilder::ForMap here?

+                            Handle<Name>::null(), Type::Internal(),
+                            kMachAnyTagged};
+  Node* receiver_map = graph()->NewNode(simplified()->LoadField(map_access),
+                                        receiver, effect, control);
+  Node* map_const = jsgraph_->Constant(map);
+  Node* cmp = graph()->NewNode(simplified()->ReferenceEqual(Type::Internal()),
+                               receiver_map, map_const);
+  Node* branch =
+      graph()->NewNode(common()->Branch(BranchHint::kTrue), cmp, control);
+  *success = graph()->NewNode(common()->IfTrue(), branch);
+  *fail = graph()->NewNode(common()->IfFalse(), branch);
+
+  if (if_smi) {
+    *fail = graph()->NewNode(common()->Merge(2), *fail, if_smi);
+  }
+}
+
+
+void JSTypeFeedbackSpecializer::GatherReceiverTypes(Node* receiver,
+                                                    Node* effect,
+                                                    TypeFeedbackId id,
+                                                    Handle<Name> name,
+                                                    SmallMapList* maps) {
+  // TODO(turbofan): filter maps by initial receiver map if known
+  // TODO(turbofan): filter maps by native context (if specializing)
+  // TODO(turbofan): filter maps by effect chain
+  oracle()->PropertyReceiverTypes(id, name, maps);
+}
+
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8