Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1 | // Copyright 2014 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 | #ifndef V8_COMPILER_REPRESENTATION_CHANGE_H_ |
| 6 | #define V8_COMPILER_REPRESENTATION_CHANGE_H_ |
| 7 | |
| 8 | #include "src/base/bits.h" |
| 9 | #include "src/compiler/js-graph.h" |
| 10 | #include "src/compiler/machine-operator.h" |
| 11 | #include "src/compiler/node-properties-inl.h" |
| 12 | #include "src/compiler/simplified-operator.h" |
| 13 | |
| 14 | namespace v8 { |
| 15 | namespace internal { |
| 16 | namespace compiler { |
| 17 | |
| 18 | // Contains logic related to changing the representation of values for constants |
| 19 | // and other nodes, as well as lowering Simplified->Machine operators. |
| 20 | // Eagerly folds any representation changes for constants. |
| 21 | class RepresentationChanger { |
| 22 | public: |
| 23 | RepresentationChanger(JSGraph* jsgraph, SimplifiedOperatorBuilder* simplified, |
| 24 | Isolate* isolate) |
| 25 | : jsgraph_(jsgraph), |
| 26 | simplified_(simplified), |
| 27 | isolate_(isolate), |
| 28 | testing_type_errors_(false), |
| 29 | type_error_(false) {} |
| 30 | |
| 31 | // TODO(titzer): should Word64 also be implicitly convertable to others? |
| 32 | static const MachineTypeUnion rWord = |
| 33 | kRepBit | kRepWord8 | kRepWord16 | kRepWord32; |
| 34 | |
| 35 | Node* GetRepresentationFor(Node* node, MachineTypeUnion output_type, |
| 36 | MachineTypeUnion use_type) { |
| 37 | if (!base::bits::IsPowerOfTwo32(output_type & kRepMask)) { |
| 38 | // There should be only one output representation. |
| 39 | return TypeError(node, output_type, use_type); |
| 40 | } |
| 41 | if ((use_type & kRepMask) == (output_type & kRepMask)) { |
| 42 | // Representations are the same. That's a no-op. |
| 43 | return node; |
| 44 | } |
| 45 | if ((use_type & rWord) && (output_type & rWord)) { |
| 46 | // Both are words less than or equal to 32-bits. |
| 47 | // Since loads of integers from memory implicitly sign or zero extend the |
| 48 | // value to the full machine word size and stores implicitly truncate, |
| 49 | // no representation change is necessary. |
| 50 | return node; |
| 51 | } |
| 52 | if (use_type & kRepTagged) { |
| 53 | return GetTaggedRepresentationFor(node, output_type); |
| 54 | } else if (use_type & kRepFloat64) { |
| 55 | return GetFloat64RepresentationFor(node, output_type); |
| 56 | } else if (use_type & kRepFloat32) { |
| 57 | return TypeError(node, output_type, use_type); // TODO(titzer): handle |
| 58 | } else if (use_type & kRepBit) { |
| 59 | return GetBitRepresentationFor(node, output_type); |
| 60 | } else if (use_type & rWord) { |
| 61 | return GetWord32RepresentationFor(node, output_type, |
| 62 | use_type & kTypeUint32); |
| 63 | } else if (use_type & kRepWord64) { |
| 64 | return GetWord64RepresentationFor(node, output_type); |
| 65 | } else { |
| 66 | return node; |
| 67 | } |
| 68 | } |
| 69 | |
| 70 | Node* GetTaggedRepresentationFor(Node* node, MachineTypeUnion output_type) { |
| 71 | // Eagerly fold representation changes for constants. |
| 72 | switch (node->opcode()) { |
| 73 | case IrOpcode::kNumberConstant: |
| 74 | case IrOpcode::kHeapConstant: |
| 75 | return node; // No change necessary. |
| 76 | case IrOpcode::kInt32Constant: |
| 77 | if (output_type & kTypeUint32) { |
| 78 | uint32_t value = OpParameter<uint32_t>(node); |
| 79 | return jsgraph()->Constant(static_cast<double>(value)); |
| 80 | } else if (output_type & kTypeInt32) { |
| 81 | int32_t value = OpParameter<int32_t>(node); |
| 82 | return jsgraph()->Constant(value); |
| 83 | } else if (output_type & kRepBit) { |
| 84 | return OpParameter<int32_t>(node) == 0 ? jsgraph()->FalseConstant() |
| 85 | : jsgraph()->TrueConstant(); |
| 86 | } else { |
| 87 | return TypeError(node, output_type, kRepTagged); |
| 88 | } |
| 89 | case IrOpcode::kFloat64Constant: |
| 90 | return jsgraph()->Constant(OpParameter<double>(node)); |
| 91 | default: |
| 92 | break; |
| 93 | } |
| 94 | // Select the correct X -> Tagged operator. |
| 95 | const Operator* op; |
| 96 | if (output_type & kRepBit) { |
| 97 | op = simplified()->ChangeBitToBool(); |
| 98 | } else if (output_type & rWord) { |
| 99 | if (output_type & kTypeUint32) { |
| 100 | op = simplified()->ChangeUint32ToTagged(); |
| 101 | } else if (output_type & kTypeInt32) { |
| 102 | op = simplified()->ChangeInt32ToTagged(); |
| 103 | } else { |
| 104 | return TypeError(node, output_type, kRepTagged); |
| 105 | } |
| 106 | } else if (output_type & kRepFloat64) { |
| 107 | op = simplified()->ChangeFloat64ToTagged(); |
| 108 | } else { |
| 109 | return TypeError(node, output_type, kRepTagged); |
| 110 | } |
| 111 | return jsgraph()->graph()->NewNode(op, node); |
| 112 | } |
| 113 | |
| 114 | Node* GetFloat64RepresentationFor(Node* node, MachineTypeUnion output_type) { |
| 115 | // Eagerly fold representation changes for constants. |
| 116 | switch (node->opcode()) { |
| 117 | case IrOpcode::kNumberConstant: |
| 118 | return jsgraph()->Float64Constant(OpParameter<double>(node)); |
| 119 | case IrOpcode::kInt32Constant: |
| 120 | if (output_type & kTypeUint32) { |
| 121 | uint32_t value = OpParameter<uint32_t>(node); |
| 122 | return jsgraph()->Float64Constant(static_cast<double>(value)); |
| 123 | } else { |
| 124 | int32_t value = OpParameter<int32_t>(node); |
| 125 | return jsgraph()->Float64Constant(value); |
| 126 | } |
| 127 | case IrOpcode::kFloat64Constant: |
| 128 | return node; // No change necessary. |
| 129 | default: |
| 130 | break; |
| 131 | } |
| 132 | // Select the correct X -> Float64 operator. |
| 133 | const Operator* op; |
| 134 | if (output_type & kRepBit) { |
| 135 | return TypeError(node, output_type, kRepFloat64); |
| 136 | } else if (output_type & rWord) { |
| 137 | if (output_type & kTypeUint32) { |
| 138 | op = machine()->ChangeUint32ToFloat64(); |
| 139 | } else { |
| 140 | op = machine()->ChangeInt32ToFloat64(); |
| 141 | } |
| 142 | } else if (output_type & kRepTagged) { |
| 143 | op = simplified()->ChangeTaggedToFloat64(); |
| 144 | } else { |
| 145 | return TypeError(node, output_type, kRepFloat64); |
| 146 | } |
| 147 | return jsgraph()->graph()->NewNode(op, node); |
| 148 | } |
| 149 | |
| 150 | Node* GetWord32RepresentationFor(Node* node, MachineTypeUnion output_type, |
| 151 | bool use_unsigned) { |
| 152 | // Eagerly fold representation changes for constants. |
| 153 | switch (node->opcode()) { |
| 154 | case IrOpcode::kInt32Constant: |
| 155 | return node; // No change necessary. |
| 156 | case IrOpcode::kNumberConstant: |
| 157 | case IrOpcode::kFloat64Constant: { |
| 158 | double value = OpParameter<double>(node); |
| 159 | if (value < 0) { |
| 160 | DCHECK(IsInt32Double(value)); |
| 161 | int32_t iv = static_cast<int32_t>(value); |
| 162 | return jsgraph()->Int32Constant(iv); |
| 163 | } else { |
| 164 | DCHECK(IsUint32Double(value)); |
| 165 | int32_t iv = static_cast<int32_t>(static_cast<uint32_t>(value)); |
| 166 | return jsgraph()->Int32Constant(iv); |
| 167 | } |
| 168 | } |
| 169 | default: |
| 170 | break; |
| 171 | } |
| 172 | // Select the correct X -> Word32 operator. |
| 173 | const Operator* op = NULL; |
| 174 | if (output_type & kRepFloat64) { |
| 175 | if (output_type & kTypeUint32 || use_unsigned) { |
| 176 | op = machine()->ChangeFloat64ToUint32(); |
| 177 | } else { |
| 178 | op = machine()->ChangeFloat64ToInt32(); |
| 179 | } |
| 180 | } else if (output_type & kRepTagged) { |
| 181 | if (output_type & kTypeUint32 || use_unsigned) { |
| 182 | op = simplified()->ChangeTaggedToUint32(); |
| 183 | } else { |
| 184 | op = simplified()->ChangeTaggedToInt32(); |
| 185 | } |
| 186 | } else { |
| 187 | return TypeError(node, output_type, kRepWord32); |
| 188 | } |
| 189 | return jsgraph()->graph()->NewNode(op, node); |
| 190 | } |
| 191 | |
| 192 | Node* GetBitRepresentationFor(Node* node, MachineTypeUnion output_type) { |
| 193 | // Eagerly fold representation changes for constants. |
| 194 | switch (node->opcode()) { |
| 195 | case IrOpcode::kInt32Constant: { |
| 196 | int32_t value = OpParameter<int32_t>(node); |
| 197 | if (value == 0 || value == 1) return node; |
| 198 | return jsgraph()->OneConstant(); // value != 0 |
| 199 | } |
| 200 | case IrOpcode::kHeapConstant: { |
| 201 | Handle<Object> handle = OpParameter<Unique<Object> >(node).handle(); |
| 202 | DCHECK(*handle == isolate()->heap()->true_value() || |
| 203 | *handle == isolate()->heap()->false_value()); |
| 204 | return jsgraph()->Int32Constant( |
| 205 | *handle == isolate()->heap()->true_value() ? 1 : 0); |
| 206 | } |
| 207 | default: |
| 208 | break; |
| 209 | } |
| 210 | // Select the correct X -> Bit operator. |
| 211 | const Operator* op; |
| 212 | if (output_type & rWord) { |
| 213 | return node; // No change necessary. |
| 214 | } else if (output_type & kRepWord64) { |
| 215 | return node; // TODO(titzer): No change necessary, on 64-bit. |
| 216 | } else if (output_type & kRepTagged) { |
| 217 | op = simplified()->ChangeBoolToBit(); |
| 218 | } else { |
| 219 | return TypeError(node, output_type, kRepBit); |
| 220 | } |
| 221 | return jsgraph()->graph()->NewNode(op, node); |
| 222 | } |
| 223 | |
| 224 | Node* GetWord64RepresentationFor(Node* node, MachineTypeUnion output_type) { |
| 225 | if (output_type & kRepBit) { |
| 226 | return node; // Sloppy comparison -> word64 |
| 227 | } |
| 228 | // Can't really convert Word64 to anything else. Purported to be internal. |
| 229 | return TypeError(node, output_type, kRepWord64); |
| 230 | } |
| 231 | |
| 232 | const Operator* Int32OperatorFor(IrOpcode::Value opcode) { |
| 233 | switch (opcode) { |
| 234 | case IrOpcode::kNumberAdd: |
| 235 | return machine()->Int32Add(); |
| 236 | case IrOpcode::kNumberSubtract: |
| 237 | return machine()->Int32Sub(); |
| 238 | case IrOpcode::kNumberMultiply: |
| 239 | return machine()->Int32Mul(); |
| 240 | case IrOpcode::kNumberDivide: |
| 241 | return machine()->Int32Div(); |
| 242 | case IrOpcode::kNumberModulus: |
| 243 | return machine()->Int32Mod(); |
| 244 | case IrOpcode::kNumberEqual: |
| 245 | return machine()->Word32Equal(); |
| 246 | case IrOpcode::kNumberLessThan: |
| 247 | return machine()->Int32LessThan(); |
| 248 | case IrOpcode::kNumberLessThanOrEqual: |
| 249 | return machine()->Int32LessThanOrEqual(); |
| 250 | default: |
| 251 | UNREACHABLE(); |
| 252 | return NULL; |
| 253 | } |
| 254 | } |
| 255 | |
| 256 | const Operator* Uint32OperatorFor(IrOpcode::Value opcode) { |
| 257 | switch (opcode) { |
| 258 | case IrOpcode::kNumberAdd: |
| 259 | return machine()->Int32Add(); |
| 260 | case IrOpcode::kNumberSubtract: |
| 261 | return machine()->Int32Sub(); |
| 262 | case IrOpcode::kNumberMultiply: |
| 263 | return machine()->Int32Mul(); |
| 264 | case IrOpcode::kNumberDivide: |
| 265 | return machine()->Int32UDiv(); |
| 266 | case IrOpcode::kNumberModulus: |
| 267 | return machine()->Int32UMod(); |
| 268 | case IrOpcode::kNumberEqual: |
| 269 | return machine()->Word32Equal(); |
| 270 | case IrOpcode::kNumberLessThan: |
| 271 | return machine()->Uint32LessThan(); |
| 272 | case IrOpcode::kNumberLessThanOrEqual: |
| 273 | return machine()->Uint32LessThanOrEqual(); |
| 274 | default: |
| 275 | UNREACHABLE(); |
| 276 | return NULL; |
| 277 | } |
| 278 | } |
| 279 | |
| 280 | const Operator* Float64OperatorFor(IrOpcode::Value opcode) { |
| 281 | switch (opcode) { |
| 282 | case IrOpcode::kNumberAdd: |
| 283 | return machine()->Float64Add(); |
| 284 | case IrOpcode::kNumberSubtract: |
| 285 | return machine()->Float64Sub(); |
| 286 | case IrOpcode::kNumberMultiply: |
| 287 | return machine()->Float64Mul(); |
| 288 | case IrOpcode::kNumberDivide: |
| 289 | return machine()->Float64Div(); |
| 290 | case IrOpcode::kNumberModulus: |
| 291 | return machine()->Float64Mod(); |
| 292 | case IrOpcode::kNumberEqual: |
| 293 | return machine()->Float64Equal(); |
| 294 | case IrOpcode::kNumberLessThan: |
| 295 | return machine()->Float64LessThan(); |
| 296 | case IrOpcode::kNumberLessThanOrEqual: |
| 297 | return machine()->Float64LessThanOrEqual(); |
| 298 | default: |
| 299 | UNREACHABLE(); |
| 300 | return NULL; |
| 301 | } |
| 302 | } |
| 303 | |
| 304 | MachineType TypeForBasePointer(const FieldAccess& access) { |
| 305 | return access.tag() != 0 ? kMachAnyTagged : kMachPtr; |
| 306 | } |
| 307 | |
| 308 | MachineType TypeForBasePointer(const ElementAccess& access) { |
| 309 | return access.tag() != 0 ? kMachAnyTagged : kMachPtr; |
| 310 | } |
| 311 | |
| 312 | MachineType TypeFromUpperBound(Type* type) { |
| 313 | if (type->Is(Type::None())) |
| 314 | return kTypeAny; // TODO(titzer): should be an error |
| 315 | if (type->Is(Type::Signed32())) return kTypeInt32; |
| 316 | if (type->Is(Type::Unsigned32())) return kTypeUint32; |
| 317 | if (type->Is(Type::Number())) return kTypeNumber; |
| 318 | if (type->Is(Type::Boolean())) return kTypeBool; |
| 319 | return kTypeAny; |
| 320 | } |
| 321 | |
| 322 | private: |
| 323 | JSGraph* jsgraph_; |
| 324 | SimplifiedOperatorBuilder* simplified_; |
| 325 | Isolate* isolate_; |
| 326 | |
| 327 | friend class RepresentationChangerTester; // accesses the below fields. |
| 328 | |
| 329 | bool testing_type_errors_; // If {true}, don't abort on a type error. |
| 330 | bool type_error_; // Set when a type error is detected. |
| 331 | |
| 332 | Node* TypeError(Node* node, MachineTypeUnion output_type, |
| 333 | MachineTypeUnion use) { |
| 334 | type_error_ = true; |
| 335 | if (!testing_type_errors_) { |
| 336 | OStringStream out_str; |
| 337 | out_str << static_cast<MachineType>(output_type); |
| 338 | |
| 339 | OStringStream use_str; |
| 340 | use_str << static_cast<MachineType>(use); |
| 341 | |
| 342 | V8_Fatal(__FILE__, __LINE__, |
| 343 | "RepresentationChangerError: node #%d:%s of " |
| 344 | "%s cannot be changed to %s", |
| 345 | node->id(), node->op()->mnemonic(), out_str.c_str(), |
| 346 | use_str.c_str()); |
| 347 | } |
| 348 | return node; |
| 349 | } |
| 350 | |
| 351 | JSGraph* jsgraph() { return jsgraph_; } |
| 352 | Isolate* isolate() { return isolate_; } |
| 353 | SimplifiedOperatorBuilder* simplified() { return simplified_; } |
| 354 | MachineOperatorBuilder* machine() { return jsgraph()->machine(); } |
| 355 | }; |
| 356 | } |
| 357 | } |
| 358 | } // namespace v8::internal::compiler |
| 359 | |
| 360 | #endif // V8_COMPILER_REPRESENTATION_CHANGE_H_ |