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
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
|
// 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.
#ifndef V8_WASM_FUNCTION_BODY_DECODER_H_
#define V8_WASM_FUNCTION_BODY_DECODER_H_
#include "src/base/compiler-specific.h"
#include "src/base/iterator.h"
#include "src/common/globals.h"
#include "src/wasm/decoder.h"
#include "src/wasm/wasm-opcodes.h"
#include "src/wasm/wasm-result.h"
namespace v8 {
namespace internal {
class BitVector; // forward declaration
namespace wasm {
class WasmFeatures;
struct WasmModule; // forward declaration of module interface.
// A wrapper around the signature and bytes of a function.
struct FunctionBody {
const FunctionSig* sig; // function signature
uint32_t offset; // offset in the module bytes, for error reporting
const byte* start; // start of the function body
const byte* end; // end of the function body
FunctionBody(const FunctionSig* sig, uint32_t offset, const byte* start,
const byte* end)
: sig(sig), offset(offset), start(start), end(end) {}
};
V8_EXPORT_PRIVATE DecodeResult VerifyWasmCode(AccountingAllocator* allocator,
const WasmFeatures& enabled,
const WasmModule* module,
WasmFeatures* detected,
const FunctionBody& body);
enum PrintLocals { kPrintLocals, kOmitLocals };
V8_EXPORT_PRIVATE
bool PrintRawWasmCode(AccountingAllocator* allocator, const FunctionBody& body,
const WasmModule* module, PrintLocals print_locals);
V8_EXPORT_PRIVATE
bool PrintRawWasmCode(AccountingAllocator* allocator, const FunctionBody& body,
const WasmModule* module, PrintLocals print_locals,
std::ostream& out,
std::vector<int>* line_numbers = nullptr);
// A simplified form of AST printing, e.g. from a debugger.
void PrintRawWasmCode(const byte* start, const byte* end);
struct BodyLocalDecls {
// The size of the encoded declarations.
uint32_t encoded_size = 0; // size of encoded declarations
ZoneVector<ValueType> type_list;
explicit BodyLocalDecls(Zone* zone) : type_list(zone) {}
};
V8_EXPORT_PRIVATE bool DecodeLocalDecls(const WasmFeatures& enabled,
BodyLocalDecls* decls,
const byte* start, const byte* end);
V8_EXPORT_PRIVATE BitVector* AnalyzeLoopAssignmentForTesting(Zone* zone,
size_t num_locals,
const byte* start,
const byte* end);
// Computes the length of the opcode at the given address.
V8_EXPORT_PRIVATE unsigned OpcodeLength(const byte* pc, const byte* end);
// Computes the stack effect of the opcode at the given address.
// Returns <pop count, push count>.
// Be cautious with control opcodes: This function only covers their immediate,
// local stack effect (e.g. BrIf pops 1, Br pops 0). Those opcodes can have
// non-local stack effect though, which are not covered here.
std::pair<uint32_t, uint32_t> StackEffect(const WasmModule* module,
const FunctionSig* sig,
const byte* pc, const byte* end);
// A simple forward iterator for bytecodes.
class V8_EXPORT_PRIVATE BytecodeIterator : public NON_EXPORTED_BASE(Decoder) {
// Base class for both iterators defined below.
class iterator_base {
public:
inline iterator_base& operator++() {
DCHECK_LT(ptr_, end_);
ptr_ += OpcodeLength(ptr_, end_);
return *this;
}
inline bool operator==(const iterator_base& that) {
return this->ptr_ == that.ptr_;
}
inline bool operator!=(const iterator_base& that) {
return this->ptr_ != that.ptr_;
}
protected:
const byte* ptr_;
const byte* end_;
iterator_base(const byte* ptr, const byte* end) : ptr_(ptr), end_(end) {}
};
public:
// If one wants to iterate over the bytecode without looking at {pc_offset()}.
class opcode_iterator
: public iterator_base,
public base::iterator<std::input_iterator_tag, WasmOpcode> {
public:
inline WasmOpcode operator*() {
DCHECK_LT(ptr_, end_);
return static_cast<WasmOpcode>(*ptr_);
}
private:
friend class BytecodeIterator;
opcode_iterator(const byte* ptr, const byte* end)
: iterator_base(ptr, end) {}
};
// If one wants to iterate over the instruction offsets without looking at
// opcodes.
class offset_iterator
: public iterator_base,
public base::iterator<std::input_iterator_tag, uint32_t> {
public:
inline uint32_t operator*() {
DCHECK_LT(ptr_, end_);
return static_cast<uint32_t>(ptr_ - start_);
}
private:
const byte* start_;
friend class BytecodeIterator;
offset_iterator(const byte* start, const byte* ptr, const byte* end)
: iterator_base(ptr, end), start_(start) {}
};
// Create a new {BytecodeIterator}. If the {decls} pointer is non-null,
// assume the bytecode starts with local declarations and decode them.
// Otherwise, do not decode local decls.
BytecodeIterator(const byte* start, const byte* end,
BodyLocalDecls* decls = nullptr);
base::iterator_range<opcode_iterator> opcodes() {
return base::iterator_range<opcode_iterator>(opcode_iterator(pc_, end_),
opcode_iterator(end_, end_));
}
base::iterator_range<offset_iterator> offsets() {
return base::iterator_range<offset_iterator>(
offset_iterator(start_, pc_, end_),
offset_iterator(start_, end_, end_));
}
WasmOpcode current() {
return static_cast<WasmOpcode>(
read_u8<Decoder::kNoValidate>(pc_, "expected bytecode"));
}
void next() {
if (pc_ < end_) {
pc_ += OpcodeLength(pc_, end_);
if (pc_ >= end_) pc_ = end_;
}
}
bool has_next() { return pc_ < end_; }
WasmOpcode prefixed_opcode() {
byte prefix = read_u8<Decoder::kNoValidate>(pc_, "expected prefix");
byte index = read_u8<Decoder::kNoValidate>(pc_ + 1, "expected index");
return static_cast<WasmOpcode>(prefix << 8 | index);
}
};
} // namespace wasm
} // namespace internal
} // namespace v8
#endif // V8_WASM_FUNCTION_BODY_DECODER_H_
|