1 // Copyright 2015 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "src/interpreter/bytecode-array-accessor.h"
6
7 #include "src/interpreter/bytecode-decoder.h"
8 #include "src/interpreter/interpreter-intrinsics.h"
9 #include "src/objects-inl.h"
10
11 namespace v8 {
12 namespace internal {
13 namespace interpreter {
14
BytecodeArrayAccessor(Handle<BytecodeArray> bytecode_array,int initial_offset)15 BytecodeArrayAccessor::BytecodeArrayAccessor(
16 Handle<BytecodeArray> bytecode_array, int initial_offset)
17 : bytecode_array_(bytecode_array),
18 bytecode_offset_(initial_offset),
19 operand_scale_(OperandScale::kSingle),
20 prefix_offset_(0) {
21 UpdateOperandScale();
22 }
23
SetOffset(int offset)24 void BytecodeArrayAccessor::SetOffset(int offset) {
25 bytecode_offset_ = offset;
26 UpdateOperandScale();
27 }
28
UpdateOperandScale()29 void BytecodeArrayAccessor::UpdateOperandScale() {
30 if (OffsetInBounds()) {
31 uint8_t current_byte = bytecode_array()->get(bytecode_offset_);
32 Bytecode current_bytecode = Bytecodes::FromByte(current_byte);
33 if (Bytecodes::IsPrefixScalingBytecode(current_bytecode)) {
34 operand_scale_ =
35 Bytecodes::PrefixBytecodeToOperandScale(current_bytecode);
36 prefix_offset_ = 1;
37 } else {
38 operand_scale_ = OperandScale::kSingle;
39 prefix_offset_ = 0;
40 }
41 }
42 }
43
OffsetInBounds() const44 bool BytecodeArrayAccessor::OffsetInBounds() const {
45 return bytecode_offset_ >= 0 && bytecode_offset_ < bytecode_array()->length();
46 }
47
current_bytecode() const48 Bytecode BytecodeArrayAccessor::current_bytecode() const {
49 DCHECK(OffsetInBounds());
50 uint8_t current_byte =
51 bytecode_array()->get(bytecode_offset_ + current_prefix_offset());
52 Bytecode current_bytecode = Bytecodes::FromByte(current_byte);
53 DCHECK(!Bytecodes::IsPrefixScalingBytecode(current_bytecode));
54 return current_bytecode;
55 }
56
current_bytecode_size() const57 int BytecodeArrayAccessor::current_bytecode_size() const {
58 return current_prefix_offset() +
59 Bytecodes::Size(current_bytecode(), current_operand_scale());
60 }
61
GetUnsignedOperand(int operand_index,OperandType operand_type) const62 uint32_t BytecodeArrayAccessor::GetUnsignedOperand(
63 int operand_index, OperandType operand_type) const {
64 DCHECK_GE(operand_index, 0);
65 DCHECK_LT(operand_index, Bytecodes::NumberOfOperands(current_bytecode()));
66 DCHECK_EQ(operand_type,
67 Bytecodes::GetOperandType(current_bytecode(), operand_index));
68 DCHECK(Bytecodes::IsUnsignedOperandType(operand_type));
69 const uint8_t* operand_start =
70 bytecode_array()->GetFirstBytecodeAddress() + bytecode_offset_ +
71 current_prefix_offset() +
72 Bytecodes::GetOperandOffset(current_bytecode(), operand_index,
73 current_operand_scale());
74 return BytecodeDecoder::DecodeUnsignedOperand(operand_start, operand_type,
75 current_operand_scale());
76 }
77
GetSignedOperand(int operand_index,OperandType operand_type) const78 int32_t BytecodeArrayAccessor::GetSignedOperand(
79 int operand_index, OperandType operand_type) const {
80 DCHECK_GE(operand_index, 0);
81 DCHECK_LT(operand_index, Bytecodes::NumberOfOperands(current_bytecode()));
82 DCHECK_EQ(operand_type,
83 Bytecodes::GetOperandType(current_bytecode(), operand_index));
84 DCHECK(!Bytecodes::IsUnsignedOperandType(operand_type));
85 const uint8_t* operand_start =
86 bytecode_array()->GetFirstBytecodeAddress() + bytecode_offset_ +
87 current_prefix_offset() +
88 Bytecodes::GetOperandOffset(current_bytecode(), operand_index,
89 current_operand_scale());
90 return BytecodeDecoder::DecodeSignedOperand(operand_start, operand_type,
91 current_operand_scale());
92 }
93
GetFlagOperand(int operand_index) const94 uint32_t BytecodeArrayAccessor::GetFlagOperand(int operand_index) const {
95 DCHECK_EQ(Bytecodes::GetOperandType(current_bytecode(), operand_index),
96 OperandType::kFlag8);
97 return GetUnsignedOperand(operand_index, OperandType::kFlag8);
98 }
99
GetUnsignedImmediateOperand(int operand_index) const100 uint32_t BytecodeArrayAccessor::GetUnsignedImmediateOperand(
101 int operand_index) const {
102 DCHECK_EQ(Bytecodes::GetOperandType(current_bytecode(), operand_index),
103 OperandType::kUImm);
104 return GetUnsignedOperand(operand_index, OperandType::kUImm);
105 }
106
GetImmediateOperand(int operand_index) const107 int32_t BytecodeArrayAccessor::GetImmediateOperand(int operand_index) const {
108 DCHECK_EQ(Bytecodes::GetOperandType(current_bytecode(), operand_index),
109 OperandType::kImm);
110 return GetSignedOperand(operand_index, OperandType::kImm);
111 }
112
GetRegisterCountOperand(int operand_index) const113 uint32_t BytecodeArrayAccessor::GetRegisterCountOperand(
114 int operand_index) const {
115 DCHECK_EQ(Bytecodes::GetOperandType(current_bytecode(), operand_index),
116 OperandType::kRegCount);
117 return GetUnsignedOperand(operand_index, OperandType::kRegCount);
118 }
119
GetIndexOperand(int operand_index) const120 uint32_t BytecodeArrayAccessor::GetIndexOperand(int operand_index) const {
121 OperandType operand_type =
122 Bytecodes::GetOperandType(current_bytecode(), operand_index);
123 DCHECK_EQ(operand_type, OperandType::kIdx);
124 return GetUnsignedOperand(operand_index, operand_type);
125 }
126
GetRegisterOperand(int operand_index) const127 Register BytecodeArrayAccessor::GetRegisterOperand(int operand_index) const {
128 OperandType operand_type =
129 Bytecodes::GetOperandType(current_bytecode(), operand_index);
130 const uint8_t* operand_start =
131 bytecode_array()->GetFirstBytecodeAddress() + bytecode_offset_ +
132 current_prefix_offset() +
133 Bytecodes::GetOperandOffset(current_bytecode(), operand_index,
134 current_operand_scale());
135 return BytecodeDecoder::DecodeRegisterOperand(operand_start, operand_type,
136 current_operand_scale());
137 }
138
GetRegisterOperandRange(int operand_index) const139 int BytecodeArrayAccessor::GetRegisterOperandRange(int operand_index) const {
140 DCHECK_LE(operand_index, Bytecodes::NumberOfOperands(current_bytecode()));
141 const OperandType* operand_types =
142 Bytecodes::GetOperandTypes(current_bytecode());
143 OperandType operand_type = operand_types[operand_index];
144 DCHECK(Bytecodes::IsRegisterOperandType(operand_type));
145 if (operand_type == OperandType::kRegList) {
146 return GetRegisterCountOperand(operand_index + 1);
147 } else {
148 return Bytecodes::GetNumberOfRegistersRepresentedBy(operand_type);
149 }
150 }
151
GetRuntimeIdOperand(int operand_index) const152 Runtime::FunctionId BytecodeArrayAccessor::GetRuntimeIdOperand(
153 int operand_index) const {
154 OperandType operand_type =
155 Bytecodes::GetOperandType(current_bytecode(), operand_index);
156 DCHECK(operand_type == OperandType::kRuntimeId);
157 uint32_t raw_id = GetUnsignedOperand(operand_index, operand_type);
158 return static_cast<Runtime::FunctionId>(raw_id);
159 }
160
GetIntrinsicIdOperand(int operand_index) const161 Runtime::FunctionId BytecodeArrayAccessor::GetIntrinsicIdOperand(
162 int operand_index) const {
163 OperandType operand_type =
164 Bytecodes::GetOperandType(current_bytecode(), operand_index);
165 DCHECK(operand_type == OperandType::kIntrinsicId);
166 uint32_t raw_id = GetUnsignedOperand(operand_index, operand_type);
167 return IntrinsicsHelper::ToRuntimeId(
168 static_cast<IntrinsicsHelper::IntrinsicId>(raw_id));
169 }
170
GetConstantForIndexOperand(int operand_index) const171 Handle<Object> BytecodeArrayAccessor::GetConstantForIndexOperand(
172 int operand_index) const {
173 return FixedArray::get(bytecode_array()->constant_pool(),
174 GetIndexOperand(operand_index),
175 bytecode_array()->GetIsolate());
176 }
177
GetJumpTargetOffset() const178 int BytecodeArrayAccessor::GetJumpTargetOffset() const {
179 Bytecode bytecode = current_bytecode();
180 if (interpreter::Bytecodes::IsJumpImmediate(bytecode)) {
181 int relative_offset = GetUnsignedImmediateOperand(0);
182 if (bytecode == Bytecode::kJumpLoop) {
183 relative_offset = -relative_offset;
184 }
185 return current_offset() + relative_offset + current_prefix_offset();
186 } else if (interpreter::Bytecodes::IsJumpConstant(bytecode)) {
187 Smi* smi = Smi::cast(*GetConstantForIndexOperand(0));
188 return current_offset() + smi->value() + current_prefix_offset();
189 } else {
190 UNREACHABLE();
191 return kMinInt;
192 }
193 }
194
OffsetWithinBytecode(int offset) const195 bool BytecodeArrayAccessor::OffsetWithinBytecode(int offset) const {
196 return current_offset() <= offset &&
197 offset < current_offset() + current_bytecode_size();
198 }
199
PrintTo(std::ostream & os) const200 std::ostream& BytecodeArrayAccessor::PrintTo(std::ostream& os) const {
201 return BytecodeDecoder::Decode(
202 os, bytecode_array()->GetFirstBytecodeAddress() + bytecode_offset_,
203 bytecode_array()->parameter_count());
204 }
205
206 } // namespace interpreter
207 } // namespace internal
208 } // namespace v8
209