Revert of [turbofan] Add initial support for global specialization.

src/compiler/js-global-specialization.cc

Index: src/compiler/js-global-specialization.cc
diff --git a/src/compiler/js-global-specialization.cc b/src/compiler/js-global-specialization.cc
deleted file mode 100644
index 4caed2e555d66032bef59839468c34f2280ecb4f..0000000000000000000000000000000000000000
--- a/src/compiler/js-global-specialization.cc
+++ /dev/null
@@ -1,240 +0,0 @@
-// 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-global-specialization.h"
-
-#include "src/compilation-dependencies.h"
-#include "src/compiler/access-builder.h"
-#include "src/compiler/js-graph.h"
-#include "src/compiler/js-operator.h"
-#include "src/contexts.h"
-#include "src/lookup.h"
-#include "src/objects-inl.h"
-
-namespace v8 {
-namespace internal {
-namespace compiler {
-
-JSGlobalSpecialization::JSGlobalSpecialization(
-    Editor* editor, JSGraph* jsgraph, Flags flags,
-    Handle<GlobalObject> global_object, CompilationDependencies* dependencies)
-    : AdvancedReducer(editor),
-      jsgraph_(jsgraph),
-      flags_(flags),
-      global_object_(global_object),
-      dependencies_(dependencies),
-      simplified_(graph()->zone()) {}
-
-
-Reduction JSGlobalSpecialization::Reduce(Node* node) {
-  switch (node->opcode()) {
-    case IrOpcode::kJSLoadGlobal:
-      return ReduceJSLoadGlobal(node);
-    case IrOpcode::kJSStoreGlobal:
-      return ReduceJSStoreGlobal(node);
-    default:
-      break;
-  }
-  return NoChange();
-}
-
-
-Reduction JSGlobalSpecialization::ReduceJSLoadGlobal(Node* node) {
-  DCHECK_EQ(IrOpcode::kJSLoadGlobal, node->opcode());
-  Handle<Name> name = LoadGlobalParametersOf(node->op()).name();
-  Node* effect = NodeProperties::GetEffectInput(node);
-
-  // Try to lookup the name on the script context table first (lexical scoping).
-  if (name->IsString()) {
-    Handle<ScriptContextTable> script_context_table(
-        global_object()->native_context()->script_context_table());
-    ScriptContextTable::LookupResult result;
-    if (ScriptContextTable::Lookup(script_context_table,
-                                   Handle<String>::cast(name), &result)) {
-      Handle<Context> script_context = ScriptContextTable::GetContext(
-          script_context_table, result.context_index);
-      if (script_context->is_the_hole(result.slot_index)) {
-        // TODO(bmeurer): Is this relevant in practice?
-        return NoChange();
-      }
-      Node* context = jsgraph()->Constant(script_context);
-      Node* value = effect = graph()->NewNode(
-          javascript()->LoadContext(0, result.slot_index,
-                                    IsImmutableVariableMode(result.mode)),
-          context, context, effect);
-      return Replace(node, value, effect);
-    }
-  }
-
-  // Lookup on the global object instead.
-  LookupIterator it(global_object(), name, LookupIterator::OWN);
-  if (it.state() == LookupIterator::DATA) {
-    return ReduceLoadFromPropertyCell(node, it.GetPropertyCell());
-  }
-
-  return NoChange();
-}
-
-
-Reduction JSGlobalSpecialization::ReduceJSStoreGlobal(Node* node) {
-  DCHECK_EQ(IrOpcode::kJSStoreGlobal, node->opcode());
-  Handle<Name> name = StoreGlobalParametersOf(node->op()).name();
-  Node* value = NodeProperties::GetValueInput(node, 2);
-  Node* effect = NodeProperties::GetEffectInput(node);
-  Node* control = NodeProperties::GetControlInput(node);
-
-  // Try to lookup the name on the script context table first (lexical scoping).
-  if (name->IsString()) {
-    Handle<ScriptContextTable> script_context_table(
-        global_object()->native_context()->script_context_table());
-    ScriptContextTable::LookupResult result;
-    if (ScriptContextTable::Lookup(script_context_table,
-                                   Handle<String>::cast(name), &result)) {
-      if (IsImmutableVariableMode(result.mode)) return NoChange();
-      Handle<Context> script_context = ScriptContextTable::GetContext(
-          script_context_table, result.context_index);
-      if (script_context->is_the_hole(result.slot_index)) {
-        // TODO(bmeurer): Is this relevant in practice?
-        return NoChange();
-      }
-      Node* context = jsgraph()->Constant(script_context);
-      effect =
-          graph()->NewNode(javascript()->StoreContext(0, result.slot_index),
-                           context, value, context, effect, control);
-      return Replace(node, value, effect, control);
-    }
-  }
-
-  // Lookup on the global object instead.
-  LookupIterator it(global_object(), name, LookupIterator::OWN);
-  if (it.state() == LookupIterator::DATA) {
-    return ReduceStoreToPropertyCell(node, it.GetPropertyCell());
-  }
-
-  return NoChange();
-}
-
-
-Reduction JSGlobalSpecialization::ReduceLoadFromPropertyCell(
-    Node* node, Handle<PropertyCell> property_cell) {
-  Node* effect = NodeProperties::GetEffectInput(node);
-  Node* control = NodeProperties::GetControlInput(node);
-  // We only specialize global data property access.
-  PropertyDetails property_details = property_cell->property_details();
-  DCHECK_EQ(kData, property_details.kind());
-  Handle<Object> property_cell_value(property_cell->value(), isolate());
-  DCHECK(!property_cell_value->IsTheHole());
-  // Load from non-configurable, read-only data property on the global
-  // object can be constant-folded, even without deoptimization support.
-  if (!property_details.IsConfigurable() && property_details.IsReadOnly()) {
-    return Replace(node, property_cell_value);
-  }
-  // Load from constant/undefined global property can be constant-folded
-  // with deoptimization support, by adding a code dependency on the cell.
-  if ((property_details.cell_type() == PropertyCellType::kConstant ||
-       property_details.cell_type() == PropertyCellType::kUndefined) &&
-      (flags() & kDeoptimizationEnabled)) {
-    dependencies()->AssumePropertyCell(property_cell);
-    return Replace(node, property_cell_value);
-  }
-  // Not much we can do if we run the generic pipeline here.
-  if (!(flags() & kTypingEnabled)) return NoChange();
-  // Load from constant type global property can benefit from representation
-  // (and map) feedback with deoptimization support (requires code dependency).
-  if (property_details.cell_type() == PropertyCellType::kConstantType &&
-      (flags() & kDeoptimizationEnabled)) {
-    dependencies()->AssumePropertyCell(property_cell);
-    Type* property_cell_value_type = Type::Any();
-    switch (property_cell->GetConstantType()) {
-      case PropertyCellConstantType::kSmi:
-        property_cell_value_type = Type::Intersect(
-            Type::SignedSmall(), Type::TaggedSigned(), graph()->zone());
-        break;
-      case PropertyCellConstantType::kStableMap: {
-        // TODO(bmeurer): Determine type based on the map's instance type.
-        property_cell_value_type = Type::TaggedPointer();
-        break;
-      }
-    }
-    Node* value = effect = graph()->NewNode(
-        simplified()->LoadField(
-            AccessBuilder::ForPropertyCellValue(property_cell_value_type)),
-        jsgraph()->Constant(property_cell), effect, control);
-    return Replace(node, value, effect);
-  }
-  // Load from non-configurable, data property on the global can be lowered to
-  // a field load, even without deoptimization, because the property cannot be
-  // deleted or reconfigured to an accessor/interceptor property.
-  if (property_details.IsConfigurable()) {
-    // With deoptimization support, we can lower loads even from configurable
-    // data properties on the global object, by adding a code dependency on
-    // the cell.
-    if (!(flags() & kDeoptimizationEnabled)) return NoChange();
-    dependencies()->AssumePropertyCell(property_cell);
-  }
-  Node* value = effect = graph()->NewNode(
-      simplified()->LoadField(AccessBuilder::ForPropertyCellValue()),
-      jsgraph()->Constant(property_cell), effect, control);
-  return Replace(node, value, effect);
-}
-
-
-Reduction JSGlobalSpecialization::ReduceStoreToPropertyCell(
-    Node* node, Handle<PropertyCell> property_cell) {
-  Node* value = NodeProperties::GetValueInput(node, 2);
-  Node* effect = NodeProperties::GetEffectInput(node);
-  Node* control = NodeProperties::GetControlInput(node);
-  // We only specialize global data property access.
-  PropertyDetails property_details = property_cell->property_details();
-  DCHECK_EQ(kData, property_details.kind());
-  Handle<Object> property_cell_value(property_cell->value(), isolate());
-  DCHECK(!property_cell_value->IsTheHole());
-  // Don't even bother trying to lower stores to read-only data properties.
-  if (property_details.IsReadOnly()) return NoChange();
-  // Not much we can do if we run the generic pipeline here.
-  if (!(flags() & kTypingEnabled)) return NoChange();
-  // TODO(bmeurer): For now we deal only with cells in mutable state.
-  if (property_details.cell_type() != PropertyCellType::kMutable) {
-    return NoChange();
-  }
-  // Store to non-configurable, data property on the global can be lowered to
-  // a field store, even without deoptimization, because the property cannot be
-  // deleted or reconfigured to an accessor/interceptor property.
-  if (property_details.IsConfigurable()) {
-    // With deoptimization support, we can lower stores even to configurable
-    // data properties on the global object, by adding a code dependency on
-    // the cell.
-    if (!(flags() & kDeoptimizationEnabled)) return NoChange();
-    dependencies()->AssumePropertyCell(property_cell);
-  }
-  effect = graph()->NewNode(
-      simplified()->StoreField(AccessBuilder::ForPropertyCellValue()),
-      jsgraph()->Constant(property_cell), value, effect, control);
-  return Replace(node, value, effect, control);
-}
-
-
-Reduction JSGlobalSpecialization::Replace(Node* node, Handle<Object> value) {
-  if (value->IsConsString()) {
-    value = String::Flatten(Handle<String>::cast(value), TENURED);
-  }
-  return Replace(node, jsgraph()->Constant(value));
-}
-
-
-Graph* JSGlobalSpecialization::graph() const { return jsgraph()->graph(); }
-
-
-Isolate* JSGlobalSpecialization::isolate() const {
-  return jsgraph()->isolate();
-}
-
-
-JSOperatorBuilder* JSGlobalSpecialization::javascript() const {
-  return jsgraph()->javascript();
-}
-
-}  // namespace compiler
-}  // namespace internal
-}  // namespace v8