handler-configuration.h

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// Copyright 2016 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.
 
#ifndef V8_IC_HANDLER_CONFIGURATION_H_
#define V8_IC_HANDLER_CONFIGURATION_H_
 
#include "src/common/globals.h"
#include "src/handles/maybe-handles.h"
#include "src/heap/heap.h"
#include "src/objects/data-handler.h"
#include "src/objects/elements-kind.h"
#include "src/objects/field-index.h"
#include "src/objects/objects.h"
#include "src/utils/utils.h"
 
// Has to be the last include (doesn't have include guards):
#include "src/objects/object-macros.h"
 
namespace v8 {
namespace internal {
 
class JSProxy;
 
enum class WasmValueType {
  kI8,
  kI16,
  kI32,
  kU32,  // Used only for loading WasmArray length.
  kI64,
  kF32,
  kF64,
  kS128,
 
  kRef,
  kRefNull,
 
  kNumTypes
};
 
// A set of bit fields representing Smi handlers for loads and a HeapObject
// that represents load handlers that can't be encoded in a Smi.
// TODO(ishell): move to load-handler.h
V8_OBJECT class LoadHandler final : public DataHandler {
 public:
  DECL_PRINTER(LoadHandler)
  DECL_VERIFIER(LoadHandler)
 
  enum class Kind {
    kElement,
    kIndexedString,
    kNormal,
    kGlobal,
    kField,
    kConstantFromPrototype,
    kAccessorFromPrototype,
    kNativeDataProperty,
    kApiGetter,
    kInterceptor,
    kSlow,
    kProxy,
    kNonExistent,
    kModuleExport
  };
  using KindBits = base::BitField<Kind, 0, 4>;
 
  // Defines whether access rights check should be done on lookup start object.
  // Applicable to named property kinds only when loading value from prototype
  // chain. Ignored when loading from lookup start object.
  using DoAccessCheckOnLookupStartObjectBits = KindBits::Next<bool, 1>;
 
  // Defines whether a lookup should be done on lookup start object before
  // proceeding to the prototype chain. Applicable to named property kinds only
  // when loading value from prototype chain. Ignored when loading from lookup
  // start object.
  using LookupOnLookupStartObjectBits =
      DoAccessCheckOnLookupStartObjectBits::Next<bool, 1>;
 
  //
  // Encoding when KindBits contains kNativeDataProperty.
  //
 
  // Index of a value entry in the descriptor array.
  using DescriptorBits =
      LookupOnLookupStartObjectBits::Next<unsigned, kDescriptorIndexBitCount>;
  // Make sure we don't overflow the smi.
  static_assert(DescriptorBits::kLastUsedBit < kSmiValueSize);
 
  //
  // Encoding when KindBits contains kField.
  //
  using IsWasmStructBits = LookupOnLookupStartObjectBits::Next<bool, 1>;
 
  //
  // Encoding when KindBits contains kField and IsWasmStructBits is 0.
  //
  using IsInobjectBits = IsWasmStructBits::Next<bool, 1>;
  using IsDoubleBits = IsInobjectBits::Next<bool, 1>;
  // +1 here is to cover all possible JSObject header sizes.
  using FieldIndexBits =
      IsDoubleBits::Next<unsigned, kDescriptorIndexBitCount + 1>;
  // Make sure we don't overflow the smi.
  static_assert(FieldIndexBits::kLastUsedBit < kSmiValueSize);
 
  //
  // Encoding when KindBits contains kField and IsWasmStructBits is 1.
  //
  using WasmFieldTypeBits = IsWasmStructBits::Next<WasmValueType, 4>;
  using WasmFieldOffsetBits = WasmFieldTypeBits::Next<unsigned, 20>;
  // Make sure we don't overflow the smi.
  static_assert(WasmFieldOffsetBits::kLastUsedBit < kSmiValueSize);
 
  //
  // Encoding when KindBits contains kElement or kIndexedString.
  //
  using AllowOutOfBoundsBits = LookupOnLookupStartObjectBits::Next<bool, 1>;
 
  //
  // Encoding when KindBits contains kElement.
  //
  using IsWasmArrayBits = AllowOutOfBoundsBits::Next<bool, 1>;
 
  //
  // Encoding when KindBits contains kElement and IsWasmArrayBits is 0.
  //
  using IsJsArrayBits = IsWasmArrayBits::Next<bool, 1>;
  using AllowHandlingHole = IsJsArrayBits::Next<bool, 1>;
  using ElementsKindBits = AllowHandlingHole::Next<ElementsKind, 8>;
  // Make sure we don't overflow the smi.
  static_assert(ElementsKindBits::kLastUsedBit < kSmiValueSize);
 
  //
  // Encoding when KindBits contains kElement and IsWasmArrayBits is 1.
  //
  using WasmArrayTypeBits = IsWasmArrayBits::Next<WasmValueType, 4>;
  // Make sure we don't overflow the smi.
  static_assert(WasmArrayTypeBits::kLastUsedBit < kSmiValueSize);
 
  //
  // Encoding when KindBits contains kModuleExport.
  //
  using ExportsIndexBits = LookupOnLookupStartObjectBits::Next<
      unsigned,
      kSmiValueSize - LookupOnLookupStartObjectBits::kLastUsedBit - 1>;
  static_assert(ExportsIndexBits::kLastUsedBit < kSmiValueSize);
 
  // Decodes kind from Smi-handler.
  static inline Kind GetHandlerKind(Tagged<Smi> smi_handler);
 
  // Creates a Smi-handler for loading a property from a slow object.
  static inline Handle<Smi> LoadNormal(Isolate* isolate);
 
  // Creates a Smi-handler for loading a property from a global object.
  static inline Handle<Smi> LoadGlobal(Isolate* isolate);
 
  // Creates a Smi-handler for loading a property from an object with an
  // interceptor.
  static inline Handle<Smi> LoadInterceptor(Isolate* isolate);
 
  // Creates a Smi-handler for loading a property from an object.
  static inline Handle<Smi> LoadSlow(Isolate* isolate);
 
  // Creates a Smi-handler for loading a field from fast object.
  static inline Handle<Smi> LoadField(Isolate* isolate, FieldIndex field_index);
 
  // Creates a Smi-handler for loading a cached constant from fast
  // prototype object.
  static inline Handle<Smi> LoadConstantFromPrototype(Isolate* isolate);
 
  // Creates a Smi-handler for calling a getter on a fast object.
  static inline DirectHandle<Smi> LoadAccessorFromPrototype(Isolate* isolate);
 
  // Creates a Smi-handler for calling a getter on a proxy.
  static inline Handle<Smi> LoadProxy(Isolate* isolate);
 
  // Creates a Smi-handler for loading a native data property from fast object.
  static inline Handle<Smi> LoadNativeDataProperty(Isolate* isolate,
                                                   int descriptor);
 
  // Creates a Smi-handler for calling a native getter on a fast object.
  static inline Handle<Smi> LoadApiGetter(Isolate* isolate);
 
  // Creates a Smi-handler for loading a Module export.
  // |index| is the index to the "value" slot in the Module's "exports"
  // dictionary.
  static inline Handle<Smi> LoadModuleExport(Isolate* isolate, int index);
 
  static inline DirectHandle<Smi> LoadWasmStructField(Isolate* isolate,
                                                      WasmValueType type,
                                                      int offset);
  static inline DirectHandle<Smi> LoadWasmArrayElement(Isolate* isolate,
                                                       WasmValueType type);
 
  // Creates a data handler that represents a load of a non-existent property.
  // {holder} is the object from which the property is loaded. If no holder is
  // needed (e.g., for "nonexistent"), null_value() may be passed in.
  static Handle<Object> LoadFullChain(Isolate* isolate,
                                      DirectHandle<Map> receiver_map,
                                      const MaybeObjectDirectHandle& holder,
                                      Handle<Smi> smi_handler);
 
  // Creates a data handler that represents a prototype chain check followed
  // by given Smi-handler that encoded a load from the holder.
  static Handle<Object> LoadFromPrototype(
      Isolate* isolate, DirectHandle<Map> receiver_map,
      DirectHandle<JSReceiver> holder, Tagged<Smi> smi_handler,
      MaybeObjectDirectHandle maybe_data1 = MaybeObjectDirectHandle(),
      MaybeObjectDirectHandle maybe_data2 = MaybeObjectDirectHandle());
 
  // Creates a Smi-handler for loading a non-existent property. Works only as
  // a part of prototype chain check.
  static inline Handle<Smi> LoadNonExistent(Isolate* isolate);
 
  // Creates a Smi-handler for loading an element.
  static inline Handle<Smi> LoadElement(Isolate* isolate,
                                        ElementsKind elements_kind,
                                        bool is_js_array,
                                        KeyedAccessLoadMode load_mode);
 
  // Creates a Smi-handler for loading from a String.
  static inline Handle<Smi> LoadIndexedString(Isolate* isolate,
                                              KeyedAccessLoadMode load_mode);
 
  // Decodes the KeyedAccessLoadMode from a {handler}.
  static KeyedAccessLoadMode GetKeyedAccessLoadMode(
      Tagged<MaybeObject> handler);
 
  // Returns true iff the handler can be used in the "holder != lookup start
  // object" case.
  static bool CanHandleHolderNotLookupStart(Tagged<Object> handler);
 
#if defined(OBJECT_PRINT)
  static void PrintHandler(Tagged<Object> handler, std::ostream& os);
#endif  // defined(OBJECT_PRINT)
} V8_OBJECT_END;
 
// A set of bit fields representing Smi handlers for stores and a HeapObject
// that represents store handlers that can't be encoded in a Smi.
// TODO(ishell): move to store-handler.h
V8_OBJECT class StoreHandler final : public DataHandler {
 public:
  DECL_PRINTER(StoreHandler)
  DECL_VERIFIER(StoreHandler)
 
  enum class Kind {
    kField,
    kConstField,
    kAccessorFromPrototype,
    kNativeDataProperty,
    kSharedStructField,
    kApiSetter,
    kGlobalProxy,
    kNormal,
    kInterceptor,
    kSlow,
    kProxy,
    kKindsNumber  // Keep last
  };
  using KindBits = base::BitField<Kind, 0, 4>;
 
  // Applicable to kGlobalProxy, kProxy kinds.
 
  // Defines whether access rights check should be done on lookup start object.
  using DoAccessCheckOnLookupStartObjectBits = KindBits::Next<bool, 1>;
 
  // Defines whether a lookup should be done on lookup start object before
  // proceeding to the prototype chain. Applicable to named property kinds only
  // when storing through prototype chain. Ignored when storing to holder.
  using LookupOnLookupStartObjectBits =
      DoAccessCheckOnLookupStartObjectBits::Next<bool, 1>;
 
  // Applicable to kField, kAccessor and kNativeDataProperty.
 
  // Index of a value entry in the descriptor array.
  using DescriptorBits =
      LookupOnLookupStartObjectBits::Next<unsigned, kDescriptorIndexBitCount>;
 
  //
  // Encoding when KindBits contains kStoreSlow.
  //
  using KeyedAccessStoreModeBits =
      LookupOnLookupStartObjectBits::Next<KeyedAccessStoreMode, 2>;
 
  //
  // Encoding when KindBits contains kField.
  //
  using IsInobjectBits = DescriptorBits::Next<bool, 1>;
  using RepresentationBits = IsInobjectBits::Next<Representation::Kind, 3>;
  // +1 here is to cover all possible JSObject header sizes.
  using FieldIndexBits =
      RepresentationBits::Next<unsigned, kDescriptorIndexBitCount + 1>;
  // Make sure we don't overflow the smi.
  static_assert(FieldIndexBits::kLastUsedBit < kSmiValueSize);
 
  // Creates a Smi-handler for storing a field to fast object.
  static inline Handle<Smi> StoreField(Isolate* isolate, int descriptor,
                                       FieldIndex field_index,
                                       PropertyConstness constness,
                                       Representation representation);
 
  // Creates a Smi-handler for storing a field to a JSSharedStruct.
  static inline Handle<Smi> StoreSharedStructField(
      Isolate* isolate, int descriptor, FieldIndex field_index,
      Representation representation);
 
  // Create a store transition handler which doesn't check prototype chain.
  static MaybeObjectHandle StoreOwnTransition(Isolate* isolate,
                                              Handle<Map> transition_map);
 
  // Create a store transition handler with prototype chain validity cell check.
  static MaybeObjectHandle StoreTransition(Isolate* isolate,
                                           Handle<Map> transition_map);
 
  // Creates a Smi-handler for storing a native data property on a fast object.
  static inline Handle<Smi> StoreNativeDataProperty(Isolate* isolate,
                                                    int descriptor);
 
  // Creates a Smi-handler for calling a setter on a fast object.
  static inline DirectHandle<Smi> StoreAccessorFromPrototype(Isolate* isolate);
 
  // Creates a Smi-handler for calling a native setter on a fast object.
  static inline DirectHandle<Smi> StoreApiSetter(Isolate* isolate);
 
  static Handle<Object> StoreThroughPrototype(
      Isolate* isolate, DirectHandle<Map> receiver_map,
      DirectHandle<JSReceiver> holder, Tagged<Smi> smi_handler,
      MaybeObjectDirectHandle maybe_data1 = MaybeObjectDirectHandle(),
      MaybeObjectDirectHandle maybe_data2 = MaybeObjectDirectHandle());
 
  static Handle<Object> StoreElementTransition(
      Isolate* isolate, DirectHandle<Map> receiver_map,
      DirectHandle<Map> transition, KeyedAccessStoreMode store_mode,
      MaybeDirectHandle<UnionOf<Smi, Cell>> prev_validity_cell =
          kNullMaybeHandle);
 
  static Handle<Object> StoreProxy(Isolate* isolate,
                                   DirectHandle<Map> receiver_map,
                                   Handle<JSProxy> proxy,
                                   DirectHandle<JSReceiver> receiver);
 
  // Creates a handler for storing a property to the property cell of a global
  // object.
  static MaybeObjectHandle StoreGlobal(Handle<PropertyCell> cell);
 
  // Creates a Smi-handler for storing a property to a global proxy object.
  static inline DirectHandle<Smi> StoreGlobalProxy(Isolate* isolate);
 
  // Creates a Smi-handler for storing a property to a slow object.
  static inline Handle<Smi> StoreNormal(Isolate* isolate);
 
  // Creates a Smi-handler for storing a property to an interceptor.
  static inline Handle<Smi> StoreInterceptor(Isolate* isolate);
 
  static inline Handle<Code> StoreSloppyArgumentsBuiltin(
      Isolate* isolate, KeyedAccessStoreMode mode);
  static inline Handle<Code> StoreFastElementBuiltin(Isolate* isolate,
                                                     KeyedAccessStoreMode mode);
  static inline DirectHandle<Code> ElementsTransitionAndStoreBuiltin(
      Isolate* isolate, KeyedAccessStoreMode mode);
 
  // Creates a Smi-handler for storing a property.
  static inline Handle<Smi> StoreSlow(
      Isolate* isolate,
      KeyedAccessStoreMode store_mode = KeyedAccessStoreMode::kInBounds);
 
  // Creates a Smi-handler for storing a property on a proxy.
  static inline Handle<Smi> StoreProxy(Isolate* isolate);
  static inline Tagged<Smi> StoreProxy();
 
  // Decodes the KeyedAccessStoreMode from a {handler}.
  static KeyedAccessStoreMode GetKeyedAccessStoreMode(
      Tagged<MaybeObject> handler);
 
#if defined(OBJECT_PRINT)
  static void PrintHandler(Tagged<Object> handler, std::ostream& os);
#endif  // defined(OBJECT_PRINT)
 
 private:
  static inline Handle<Smi> StoreField(Isolate* isolate, Kind kind,
                                       int descriptor, FieldIndex field_index,
                                       Representation representation);
} V8_OBJECT_END;
 
inline const char* WasmValueType2String(WasmValueType type);
 
std::ostream& operator<<(std::ostream& os, WasmValueType type);
 
}  // namespace internal
}  // namespace v8
 
#include "src/objects/object-macros-undef.h"
 
#endif  // V8_IC_HANDLER_CONFIGURATION_H_