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arguments.h
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27 
28 #ifndef V8_ARGUMENTS_H_
29 #define V8_ARGUMENTS_H_
30 
31 #include "allocation.h"
32 
33 namespace v8 {
34 namespace internal {
35 
36 // Arguments provides access to runtime call parameters.
37 //
38 // It uses the fact that the instance fields of Arguments
39 // (length_, arguments_) are "overlayed" with the parameters
40 // (no. of parameters, and the parameter pointer) passed so
41 // that inside the C++ function, the parameters passed can
42 // be accessed conveniently:
43 //
44 // Object* Runtime_function(Arguments args) {
45 // ... use args[i] here ...
46 // }
47 
49  public:
50  Arguments(int length, Object** arguments)
51  : length_(length), arguments_(arguments) { }
52 
53  Object*& operator[] (int index) {
54  ASSERT(0 <= index && index < length_);
55  return arguments_[-index];
56  }
57 
58  template <class S> Handle<S> at(int index) {
59  Object** value = &((*this)[index]);
60  // This cast checks that the object we're accessing does indeed have the
61  // expected type.
62  S::cast(*value);
63  return Handle<S>(reinterpret_cast<S**>(value));
64  }
65 
66  int smi_at(int index) {
67  return Smi::cast((*this)[index])->value();
68  }
69 
70  double number_at(int index) {
71  return (*this)[index]->Number();
72  }
73 
74  // Get the total number of arguments including the receiver.
75  int length() const { return length_; }
76 
77  Object** arguments() { return arguments_; }
78 
79  private:
80  int length_;
81  Object** arguments_;
82 };
83 
84 
85 // Custom arguments replicate a small segment of stack that can be
86 // accessed through an Arguments object the same way the actual stack
87 // can.
88 class CustomArguments : public Relocatable {
89  public:
90  inline CustomArguments(Isolate* isolate,
91  Object* data,
92  Object* self,
93  JSObject* holder) : Relocatable(isolate) {
94  ASSERT(reinterpret_cast<Object*>(isolate)->IsSmi());
95  values_[3] = self;
96  values_[2] = holder;
97  values_[1] = data;
98  values_[0] = reinterpret_cast<Object*>(isolate);
99  }
100 
101  inline explicit CustomArguments(Isolate* isolate) : Relocatable(isolate) {
102 #ifdef DEBUG
103  for (size_t i = 0; i < ARRAY_SIZE(values_); i++) {
104  values_[i] = reinterpret_cast<Object*>(kZapValue);
105  }
106 #endif
107  }
108 
109  void IterateInstance(ObjectVisitor* v);
110  Object** end() { return values_ + ARRAY_SIZE(values_) - 1; }
111 
112  private:
113  Object* values_[4];
114 };
115 
116 
117 #define DECLARE_RUNTIME_FUNCTION(Type, Name) \
118 Type Name(Arguments args, Isolate* isolate)
119 
120 
121 #define RUNTIME_FUNCTION(Type, Name) \
122 Type Name(Arguments args, Isolate* isolate)
123 
124 
125 #define RUNTIME_ARGUMENTS(isolate, args) args, isolate
126 
127 
128 } } // namespace v8::internal
129 
130 #endif // V8_ARGUMENTS_H_
int smi_at(int index)
Definition: arguments.h:66
CustomArguments(Isolate *isolate)
Definition: arguments.h:101
Handle< S > at(int index)
Definition: arguments.h:58
#define ASSERT(condition)
Definition: checks.h:270
static Smi * cast(Object *object)
const Address kZapValue
Definition: v8globals.h:80
Arguments(int length, Object **arguments)
Definition: arguments.h:50
#define BASE_EMBEDDED
Definition: allocation.h:68
void IterateInstance(ObjectVisitor *v)
Definition: handles.cc:541
double number_at(int index)
Definition: arguments.h:70
CustomArguments(Isolate *isolate, Object *data, Object *self, JSObject *holder)
Definition: arguments.h:90
#define ARRAY_SIZE(a)
Definition: globals.h:281