| // 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. |
| |
| #ifndef V8_OBJECTS_ARGUMENTS_H_ |
| #define V8_OBJECTS_ARGUMENTS_H_ |
| |
| #include "src/objects/fixed-array.h" |
| #include "src/objects/js-objects.h" |
| #include "src/objects/struct.h" |
| |
| // Has to be the last include (doesn't have include guards): |
| #include "src/objects/object-macros.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| class StructBodyDescriptor; |
| |
| #include "torque-generated/src/objects/arguments-tq.inc" |
| |
| // Superclass for all objects with instance type {JS_ARGUMENTS_OBJECT_TYPE} |
| class JSArgumentsObject |
| : public TorqueGeneratedJSArgumentsObject<JSArgumentsObject, JSObject> { |
| public: |
| DECL_VERIFIER(JSArgumentsObject) |
| DECL_PRINTER(JSArgumentsObject) |
| TQ_OBJECT_CONSTRUCTORS(JSArgumentsObject) |
| }; |
| |
| // JSSloppyArgumentsObject is just a JSArgumentsObject with specific initial |
| // map. This initial map adds in-object properties for "length" and "callee". |
| class JSSloppyArgumentsObject |
| : public TorqueGeneratedJSSloppyArgumentsObject<JSSloppyArgumentsObject, |
| JSArgumentsObject> { |
| public: |
| // Indices of in-object properties. |
| static const int kLengthIndex = 0; |
| static const int kCalleeIndex = kLengthIndex + 1; |
| |
| private: |
| DISALLOW_IMPLICIT_CONSTRUCTORS(JSSloppyArgumentsObject); |
| }; |
| |
| // JSStrictArgumentsObject is just a JSArgumentsObject with specific initial |
| // map. This initial map adds an in-object property for "length". |
| class JSStrictArgumentsObject |
| : public TorqueGeneratedJSStrictArgumentsObject<JSStrictArgumentsObject, |
| JSArgumentsObject> { |
| public: |
| // Indices of in-object properties. |
| static const int kLengthIndex = 0; |
| static_assert(kLengthIndex == JSSloppyArgumentsObject::kLengthIndex); |
| |
| private: |
| DISALLOW_IMPLICIT_CONSTRUCTORS(JSStrictArgumentsObject); |
| }; |
| |
| // Representation of a slow alias as part of a sloppy arguments objects. |
| // For fast aliases (if HasSloppyArgumentsElements()): |
| // - the parameter map contains an index into the context |
| // - all attributes of the element have default values |
| // For slow aliases (if HasDictionaryArgumentsElements()): |
| // - the parameter map contains no fast alias mapping (i.e. the hole) |
| // - this struct (in the slow backing store) contains an index into the context |
| // - all attributes are available as part if the property details |
| class AliasedArgumentsEntry |
| : public TorqueGeneratedAliasedArgumentsEntry<AliasedArgumentsEntry, |
| Struct> { |
| public: |
| using BodyDescriptor = StructBodyDescriptor; |
| |
| TQ_OBJECT_CONSTRUCTORS(AliasedArgumentsEntry) |
| }; |
| |
| // Helper class to access FAST_ and SLOW_SLOPPY_ARGUMENTS_ELEMENTS, dividing |
| // arguments into two types for a given SloppyArgumentsElements object: |
| // mapped and unmapped. |
| // |
| // For clarity SloppyArgumentsElements fields are qualified with "elements." |
| // below. |
| // |
| // Mapped arguments are actual arguments. Unmapped arguments are values added |
| // to the arguments object after it was created for the call. Mapped arguments |
| // are stored in the context at indexes given by elements.mapped_entries[key]. |
| // Unmapped arguments are stored as regular indexed properties in the arguments |
| // array which can be accessed from elements.arguments. |
| // |
| // elements.length is min(number_of_actual_arguments, |
| // number_of_formal_arguments) for a concrete call to a function. |
| // |
| // Once a SloppyArgumentsElements is generated, lookup of an argument with index |
| // |key| in |elements| works as follows: |
| // |
| // If key >= elements.length then attempt to look in the unmapped arguments |
| // array and return the value at key, missing to the runtime if the unmapped |
| // arguments array is not a fixed array or if key >= elements.arguments.length. |
| // |
| // Otherwise, t = elements.mapped_entries[key]. If t is the hole, then the |
| // entry has been deleted from the arguments object, and value is looked up in |
| // the unmapped arguments array, as described above. Otherwise, t is a Smi |
| // index into the context array specified at elements.context, and the return |
| // value is elements.context[t]. |
| // |
| // A graphic representation of a SloppyArgumentsElements object and a |
| // corresponding unmapped arguments FixedArray: |
| // |
| // SloppyArgumentsElements |
| // +---+-----------------------+ |
| // | Context context | |
| // +---------------------------+ |
| // | FixedArray arguments +----+ HOLEY_ELEMENTS |
| // +---------------------------+ v-----+-----------+ |
| // | 0 | Object mapped_entries | | 0 | the_hole | |
| // |...| ... | | ... | ... | |
| // |n-1| Object mapped_entries | | n-1 | the_hole | |
| // +---------------------------+ | n | element_1 | |
| // | ... | ... | |
| // |n+m-1| element_m | |
| // +-----------------+ |
| // |
| // The elements.arguments backing store kind depends on the ElementsKind of |
| // the outer JSArgumentsObject: |
| // - FAST_SLOPPY_ARGUMENTS_ELEMENTS: HOLEY_ELEMENTS |
| // - SLOW_SLOPPY_ARGUMENTS_ELEMENTS: DICTIONARY_ELEMENTS |
| class SloppyArgumentsElements : public FixedArrayBase { |
| OBJECT_CONSTRUCTORS(SloppyArgumentsElements, FixedArrayBase); |
| |
| public: |
| inline Tagged<Context> context() const; |
| inline void set_context(Tagged<Context> value, |
| WriteBarrierMode mode = UPDATE_WRITE_BARRIER); |
| |
| // Returns: FixedArray|NumberDictionary. |
| inline Tagged<FixedArray> arguments() const; |
| inline void set_arguments(Tagged<FixedArray> value, |
| WriteBarrierMode mode = UPDATE_WRITE_BARRIER); |
| |
| // Returns: Smi|TheHole. |
| inline Tagged<Object> mapped_entries(int index, RelaxedLoadTag) const; |
| inline void set_mapped_entries(int index, Tagged<Object> value); |
| inline void set_mapped_entries(int index, Tagged<Object> value, |
| RelaxedStoreTag); |
| |
| inline int AllocatedSize() const; |
| |
| static constexpr int SizeFor(int length) { return OffsetOfElementAt(length); } |
| static constexpr int OffsetOfElementAt(int index) { |
| return kHeaderSize + index * kTaggedSize; |
| } |
| |
| DECL_CAST(SloppyArgumentsElements) |
| DECL_PRINTER(SloppyArgumentsElements) |
| DECL_VERIFIER(SloppyArgumentsElements) |
| |
| #define FIELD_LIST(V) \ |
| V(kContextOffset, kTaggedSize) \ |
| V(kArgumentsOffset, kTaggedSize) \ |
| V(kUnalignedHeaderSize, OBJECT_POINTER_PADDING(kUnalignedHeaderSize)) \ |
| V(kHeaderSize, 0) \ |
| V(kMappedEntriesOffset, 0) // mapped_entries[length] |
| |
| DEFINE_FIELD_OFFSET_CONSTANTS(FixedArrayBase::kHeaderSize, FIELD_LIST) |
| #undef FIELD_LIST |
| |
| class BodyDescriptor; |
| }; |
| |
| } // namespace internal |
| } // namespace v8 |
| |
| #include "src/objects/object-macros-undef.h" |
| |
| #endif // V8_OBJECTS_ARGUMENTS_H_ |