blob: 9e23fa8b61dbfcd470c868baee134edceff50951 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
|
// 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.h"
// Has to be the last include (doesn't have include guards):
#include "src/objects/object-macros.h"
namespace v8 {
namespace internal {
// Common superclass for JSSloppyArgumentsObject and JSStrictArgumentsObject.
// Note that the instance type {JS_ARGUMENTS_TYPE} does _not_ guarantee the
// below layout, the in-object properties might have transitioned to dictionary
// mode already. Only use the below layout with the specific initial maps.
class JSArgumentsObject : public JSObject {
public:
// Offsets of object fields.
static const int kLengthOffset = JSObject::kHeaderSize;
static const int kSize = kLengthOffset + kPointerSize;
// Indices of in-object properties.
static const int kLengthIndex = 0;
DECL_VERIFIER(JSArgumentsObject)
DECL_CAST(JSArgumentsObject)
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(JSArgumentsObject);
};
// JSSloppyArgumentsObject is just a JSObject with specific initial map.
// This initial map adds in-object properties for "length" and "callee".
class JSSloppyArgumentsObject : public JSArgumentsObject {
public:
// Offsets of object fields.
static const int kCalleeOffset = JSArgumentsObject::kSize;
static const int kSize = kCalleeOffset + kPointerSize;
// Indices of in-object properties.
static const int kCalleeIndex = kLengthIndex + 1;
inline static bool GetSloppyArgumentsLength(Isolate* isolate,
Handle<JSObject> object,
int* out);
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(JSSloppyArgumentsObject);
};
// JSStrictArgumentsObject is just a JSObject with specific initial map.
// This initial map adds an in-object property for "length".
class JSStrictArgumentsObject : public JSArgumentsObject {
public:
// Offsets of object fields.
static const int kSize = JSArgumentsObject::kSize;
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(JSStrictArgumentsObject);
};
// Helper class to access FAST_ and SLOW_SLOPPY_ARGUMENTS_ELEMENTS
//
// +---+-----------------------+
// | 0 | Context* context |
// +---------------------------+
// | 1 | FixedArray* arguments +----+ HOLEY_ELEMENTS
// +---------------------------+ v-----+-----------+
// | 2 | Object* param_1_map | | 0 | the_hole |
// |...| ... | | ... | ... |
// |n+1| Object* param_n_map | | n-1 | the_hole |
// +---------------------------+ | n | element_1 |
// | ... | ... |
// |n+m-1| element_m |
// +-----------------+
//
// Parameter maps give the index into the provided context. If a map entry is
// the_hole it means that the given entry has been deleted from the arguments
// object.
// The 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 FixedArray {
public:
static const int kContextIndex = 0;
static const int kArgumentsIndex = 1;
static const uint32_t kParameterMapStart = 2;
inline Context* context();
inline FixedArray* arguments();
inline void set_arguments(FixedArray* arguments);
inline uint32_t parameter_map_length();
inline Object* get_mapped_entry(uint32_t entry);
inline void set_mapped_entry(uint32_t entry, Object* object);
DECL_CAST(SloppyArgumentsElements)
#ifdef VERIFY_HEAP
void SloppyArgumentsElementsVerify(Isolate* isolate, JSObject* holder);
#endif
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(SloppyArgumentsElements);
};
// 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 Struct {
public:
inline int aliased_context_slot() const;
inline void set_aliased_context_slot(int count);
DECL_CAST(AliasedArgumentsEntry)
// Dispatched behavior.
DECL_PRINTER(AliasedArgumentsEntry)
DECL_VERIFIER(AliasedArgumentsEntry)
static const int kAliasedContextSlot = HeapObject::kHeaderSize;
static const int kSize = kAliasedContextSlot + kPointerSize;
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(AliasedArgumentsEntry);
};
} // namespace internal
} // namespace v8
#include "src/objects/object-macros-undef.h"
#endif // V8_OBJECTS_ARGUMENTS_H_
|