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/signature.h" 6 7 #include "src/bit-vector.h" 8 #include "src/flags.h" 9 #include "src/handles.h" 10 #include "src/zone-containers.h" 11 12 #include "src/wasm/ast-decoder.h" 13 #include "src/wasm/decoder.h" 14 #include "src/wasm/wasm-module.h" 15 #include "src/wasm/wasm-opcodes.h" 16 17 #include "src/ostreams.h" 18 19 #include "src/compiler/wasm-compiler.h" 20 21 namespace v8 { 22 namespace internal { 23 namespace wasm { 24 25 #if DEBUG 26 #define TRACE(...) \ 27 do { \ 28 if (FLAG_trace_wasm_decoder) PrintF(__VA_ARGS__); \ 29 } while (false) 30 #else 31 #define TRACE(...) 32 #endif 33 34 // The root of a decoded tree. 35 struct Tree { 36 LocalType type; // tree type. 37 uint32_t count; // number of children. 38 const byte* pc; // start of the syntax tree. 39 TFNode* node; // node in the TurboFan graph. 40 Tree* children[1]; // pointers to children. 41 42 WasmOpcode opcode() const { return static_cast<WasmOpcode>(*pc); } 43 }; 44 45 // An SsaEnv environment carries the current local variable renaming 46 // as well as the current effect and control dependency in the TF graph. 47 // It maintains a control state that tracks whether the environment 48 // is reachable, has reached a control end, or has been merged. 49 struct SsaEnv { 50 enum State { kControlEnd, kUnreachable, kReached, kMerged }; 51 52 State state; 53 TFNode* control; 54 TFNode* effect; 55 TFNode** locals; 56 57 bool go() { return state >= kReached; } 58 void Kill(State new_state = kControlEnd) { 59 state = new_state; 60 locals = nullptr; 61 control = nullptr; 62 effect = nullptr; 63 } 64 void SetNotMerged() { 65 if (state == kMerged) state = kReached; 66 } 67 }; 68 69 // An entry on the value stack. 70 struct Value { 71 const byte* pc; 72 TFNode* node; 73 LocalType type; 74 }; 75 76 // An entry on the control stack (i.e. if, block, loop). 77 struct Control { 78 const byte* pc; 79 int stack_depth; // stack height at the beginning of the construct. 80 SsaEnv* end_env; // end environment for the construct. 81 SsaEnv* false_env; // false environment (only for if). 82 TFNode* node; // result node for the construct. 83 LocalType type; // result type for the construct. 84 bool is_loop; // true if this is the inner label of a loop. 85 86 bool is_if() { return *pc == kExprIf; } 87 bool is_block() { return *pc == kExprBlock; } 88 }; 89 90 // Macros that build nodes only if there is a graph and the current SSA 91 // environment is reachable from start. This avoids problems with malformed 92 // TF graphs when decoding inputs that have unreachable code. 93 #define BUILD(func, ...) (build() ? builder_->func(__VA_ARGS__) : nullptr) 94 #define BUILD0(func) (build() ? builder_->func() : nullptr) 95 96 // Generic Wasm bytecode decoder with utilities for decoding operands, 97 // lengths, etc. 98 class WasmDecoder : public Decoder { 99 public: 100 WasmDecoder(ModuleEnv* module, FunctionSig* sig, const byte* start, 101 const byte* end) 102 : Decoder(start, end), 103 module_(module), 104 sig_(sig), 105 total_locals_(0), 106 local_types_(nullptr) {} 107 ModuleEnv* module_; 108 FunctionSig* sig_; 109 size_t total_locals_; 110 ZoneVector<LocalType>* local_types_; 111 112 byte ByteOperand(const byte* pc, const char* msg = "missing 1-byte operand") { 113 if ((pc + sizeof(byte)) >= limit_) { 114 error(pc, msg); 115 return 0; 116 } 117 return pc[1]; 118 } 119 120 uint32_t Uint32Operand(const byte* pc) { 121 if ((pc + sizeof(uint32_t)) >= limit_) { 122 error(pc, "missing 4-byte operand"); 123 return 0; 124 } 125 return read_u32(pc + 1); 126 } 127 128 uint64_t Uint64Operand(const byte* pc) { 129 if ((pc + sizeof(uint64_t)) >= limit_) { 130 error(pc, "missing 8-byte operand"); 131 return 0; 132 } 133 return read_u64(pc + 1); 134 } 135 136 inline bool Validate(const byte* pc, LocalIndexOperand& operand) { 137 if (operand.index < total_locals_) { 138 if (local_types_) { 139 operand.type = local_types_->at(operand.index); 140 } else { 141 operand.type = kAstStmt; 142 } 143 return true; 144 } 145 error(pc, pc + 1, "invalid local index"); 146 return false; 147 } 148 149 inline bool Validate(const byte* pc, GlobalIndexOperand& operand) { 150 ModuleEnv* m = module_; 151 if (m && m->module && operand.index < m->module->globals.size()) { 152 operand.machine_type = m->module->globals[operand.index].type; 153 operand.type = WasmOpcodes::LocalTypeFor(operand.machine_type); 154 return true; 155 } 156 error(pc, pc + 1, "invalid global index"); 157 return false; 158 } 159 160 inline bool Complete(const byte* pc, CallFunctionOperand& operand) { 161 ModuleEnv* m = module_; 162 if (m && m->module && operand.index < m->module->functions.size()) { 163 operand.sig = m->module->functions[operand.index].sig; 164 return true; 165 } 166 return false; 167 } 168 169 inline bool Validate(const byte* pc, CallFunctionOperand& operand) { 170 if (Complete(pc, operand)) { 171 uint32_t expected = static_cast<uint32_t>(operand.sig->parameter_count()); 172 if (operand.arity != expected) { 173 error(pc, pc + 1, 174 "arity mismatch in direct function call (expected %u, got %u)", 175 expected, operand.arity); 176 return false; 177 } 178 return true; 179 } 180 error(pc, pc + 1, "invalid function index"); 181 return false; 182 } 183 184 inline bool Complete(const byte* pc, CallIndirectOperand& operand) { 185 ModuleEnv* m = module_; 186 if (m && m->module && operand.index < m->module->signatures.size()) { 187 operand.sig = m->module->signatures[operand.index]; 188 return true; 189 } 190 return false; 191 } 192 193 inline bool Validate(const byte* pc, CallIndirectOperand& operand) { 194 if (Complete(pc, operand)) { 195 uint32_t expected = static_cast<uint32_t>(operand.sig->parameter_count()); 196 if (operand.arity != expected) { 197 error(pc, pc + 1, 198 "arity mismatch in indirect function call (expected %u, got %u)", 199 expected, operand.arity); 200 return false; 201 } 202 return true; 203 } 204 error(pc, pc + 1, "invalid signature index"); 205 return false; 206 } 207 208 inline bool Complete(const byte* pc, CallImportOperand& operand) { 209 ModuleEnv* m = module_; 210 if (m && m->module && operand.index < m->module->import_table.size()) { 211 operand.sig = m->module->import_table[operand.index].sig; 212 return true; 213 } 214 return false; 215 } 216 217 inline bool Validate(const byte* pc, CallImportOperand& operand) { 218 if (Complete(pc, operand)) { 219 uint32_t expected = static_cast<uint32_t>(operand.sig->parameter_count()); 220 if (operand.arity != expected) { 221 error(pc, pc + 1, "arity mismatch in import call (expected %u, got %u)", 222 expected, operand.arity); 223 return false; 224 } 225 return true; 226 } 227 error(pc, pc + 1, "invalid signature index"); 228 return false; 229 } 230 231 inline bool Validate(const byte* pc, BreakDepthOperand& operand, 232 ZoneVector<Control>& control) { 233 if (operand.arity > 1) { 234 error(pc, pc + 1, "invalid arity for br or br_if"); 235 return false; 236 } 237 if (operand.depth < control.size()) { 238 operand.target = &control[control.size() - operand.depth - 1]; 239 return true; 240 } 241 error(pc, pc + 1, "invalid break depth"); 242 return false; 243 } 244 245 bool Validate(const byte* pc, BranchTableOperand& operand, 246 size_t block_depth) { 247 if (operand.arity > 1) { 248 error(pc, pc + 1, "invalid arity for break"); 249 return false; 250 } 251 // Verify table. 252 for (uint32_t i = 0; i < operand.table_count + 1; ++i) { 253 uint32_t target = operand.read_entry(this, i); 254 if (target >= block_depth) { 255 error(operand.table + i * 2, "improper branch in br_table"); 256 return false; 257 } 258 } 259 return true; 260 } 261 262 unsigned OpcodeArity(const byte* pc) { 263 #define DECLARE_ARITY(name, ...) \ 264 static const LocalType kTypes_##name[] = {__VA_ARGS__}; \ 265 static const int kArity_##name = \ 266 static_cast<int>(arraysize(kTypes_##name) - 1); 267 268 FOREACH_SIGNATURE(DECLARE_ARITY); 269 #undef DECLARE_ARITY 270 271 switch (static_cast<WasmOpcode>(*pc)) { 272 case kExprI8Const: 273 case kExprI32Const: 274 case kExprI64Const: 275 case kExprF64Const: 276 case kExprF32Const: 277 case kExprGetLocal: 278 case kExprLoadGlobal: 279 case kExprNop: 280 case kExprUnreachable: 281 case kExprEnd: 282 case kExprBlock: 283 case kExprLoop: 284 return 0; 285 286 case kExprStoreGlobal: 287 case kExprSetLocal: 288 case kExprElse: 289 return 1; 290 291 case kExprBr: { 292 BreakDepthOperand operand(this, pc); 293 return operand.arity; 294 } 295 case kExprBrIf: { 296 BreakDepthOperand operand(this, pc); 297 return 1 + operand.arity; 298 } 299 case kExprBrTable: { 300 BranchTableOperand operand(this, pc); 301 return 1 + operand.arity; 302 } 303 304 case kExprIf: 305 return 1; 306 case kExprSelect: 307 return 3; 308 309 case kExprCallFunction: { 310 CallFunctionOperand operand(this, pc); 311 return operand.arity; 312 } 313 case kExprCallIndirect: { 314 CallIndirectOperand operand(this, pc); 315 return 1 + operand.arity; 316 } 317 case kExprCallImport: { 318 CallImportOperand operand(this, pc); 319 return operand.arity; 320 } 321 case kExprReturn: { 322 ReturnArityOperand operand(this, pc); 323 return operand.arity; 324 } 325 326 #define DECLARE_OPCODE_CASE(name, opcode, sig) \ 327 case kExpr##name: \ 328 return kArity_##sig; 329 330 FOREACH_LOAD_MEM_OPCODE(DECLARE_OPCODE_CASE) 331 FOREACH_STORE_MEM_OPCODE(DECLARE_OPCODE_CASE) 332 FOREACH_MISC_MEM_OPCODE(DECLARE_OPCODE_CASE) 333 FOREACH_SIMPLE_OPCODE(DECLARE_OPCODE_CASE) 334 FOREACH_ASMJS_COMPAT_OPCODE(DECLARE_OPCODE_CASE) 335 FOREACH_SIMD_OPCODE(DECLARE_OPCODE_CASE) 336 #undef DECLARE_OPCODE_CASE 337 default: 338 UNREACHABLE(); 339 return 0; 340 } 341 } 342 343 unsigned OpcodeLength(const byte* pc) { 344 switch (static_cast<WasmOpcode>(*pc)) { 345 #define DECLARE_OPCODE_CASE(name, opcode, sig) case kExpr##name: 346 FOREACH_LOAD_MEM_OPCODE(DECLARE_OPCODE_CASE) 347 FOREACH_STORE_MEM_OPCODE(DECLARE_OPCODE_CASE) 348 #undef DECLARE_OPCODE_CASE 349 { 350 MemoryAccessOperand operand(this, pc); 351 return 1 + operand.length; 352 } 353 case kExprBr: 354 case kExprBrIf: { 355 BreakDepthOperand operand(this, pc); 356 return 1 + operand.length; 357 } 358 case kExprStoreGlobal: 359 case kExprLoadGlobal: { 360 GlobalIndexOperand operand(this, pc); 361 return 1 + operand.length; 362 } 363 364 case kExprCallFunction: { 365 CallFunctionOperand operand(this, pc); 366 return 1 + operand.length; 367 } 368 case kExprCallIndirect: { 369 CallIndirectOperand operand(this, pc); 370 return 1 + operand.length; 371 } 372 case kExprCallImport: { 373 CallImportOperand operand(this, pc); 374 return 1 + operand.length; 375 } 376 377 case kExprSetLocal: 378 case kExprGetLocal: { 379 LocalIndexOperand operand(this, pc); 380 return 1 + operand.length; 381 } 382 case kExprBrTable: { 383 BranchTableOperand operand(this, pc); 384 return 1 + operand.length; 385 } 386 case kExprI32Const: { 387 ImmI32Operand operand(this, pc); 388 return 1 + operand.length; 389 } 390 case kExprI64Const: { 391 ImmI64Operand operand(this, pc); 392 return 1 + operand.length; 393 } 394 case kExprI8Const: 395 return 2; 396 case kExprF32Const: 397 return 5; 398 case kExprF64Const: 399 return 9; 400 case kExprReturn: { 401 ReturnArityOperand operand(this, pc); 402 return 1 + operand.length; 403 } 404 405 default: 406 return 1; 407 } 408 } 409 }; 410 411 // A shift-reduce-parser strategy for decoding Wasm code that uses an explicit 412 // shift-reduce strategy with multiple internal stacks. 413 class SR_WasmDecoder : public WasmDecoder { 414 public: 415 SR_WasmDecoder(Zone* zone, TFBuilder* builder, const FunctionBody& body) 416 : WasmDecoder(body.module, body.sig, body.start, body.end), 417 zone_(zone), 418 builder_(builder), 419 base_(body.base), 420 local_type_vec_(zone), 421 stack_(zone), 422 control_(zone) { 423 local_types_ = &local_type_vec_; 424 } 425 426 bool Decode() { 427 base::ElapsedTimer decode_timer; 428 if (FLAG_trace_wasm_decode_time) { 429 decode_timer.Start(); 430 } 431 stack_.clear(); 432 control_.clear(); 433 434 if (end_ < pc_) { 435 error(pc_, "function body end < start"); 436 return false; 437 } 438 439 DecodeLocalDecls(); 440 InitSsaEnv(); 441 DecodeFunctionBody(); 442 443 if (failed()) return TraceFailed(); 444 445 if (!control_.empty()) { 446 error(pc_, control_.back().pc, "unterminated control structure"); 447 return TraceFailed(); 448 } 449 450 if (ssa_env_->go()) { 451 TRACE(" @%-6d #xx:%-20s|", startrel(pc_), "ImplicitReturn"); 452 DoReturn(); 453 if (failed()) return TraceFailed(); 454 TRACE("\n"); 455 } 456 457 if (FLAG_trace_wasm_decode_time) { 458 double ms = decode_timer.Elapsed().InMillisecondsF(); 459 PrintF("wasm-decode ok (%0.3f ms)\n\n", ms); 460 } else { 461 TRACE("wasm-decode ok\n\n"); 462 } 463 464 return true; 465 } 466 467 bool TraceFailed() { 468 TRACE("wasm-error module+%-6d func+%d: %s\n\n", baserel(error_pc_), 469 startrel(error_pc_), error_msg_.get()); 470 return false; 471 } 472 473 bool DecodeLocalDecls(AstLocalDecls& decls) { 474 DecodeLocalDecls(); 475 if (failed()) return false; 476 decls.decls_encoded_size = pc_offset(); 477 decls.local_types.reserve(local_type_vec_.size()); 478 for (size_t pos = 0; pos < local_type_vec_.size();) { 479 uint32_t count = 0; 480 LocalType type = local_type_vec_[pos]; 481 while (pos < local_type_vec_.size() && local_type_vec_[pos] == type) { 482 pos++; 483 count++; 484 } 485 decls.local_types.push_back(std::pair<LocalType, uint32_t>(type, count)); 486 } 487 decls.total_local_count = static_cast<uint32_t>(local_type_vec_.size()); 488 return true; 489 } 490 491 BitVector* AnalyzeLoopAssignmentForTesting(const byte* pc, 492 size_t num_locals) { 493 total_locals_ = num_locals; 494 local_type_vec_.reserve(num_locals); 495 if (num_locals > local_type_vec_.size()) { 496 local_type_vec_.insert(local_type_vec_.end(), 497 num_locals - local_type_vec_.size(), kAstI32); 498 } 499 return AnalyzeLoopAssignment(pc); 500 } 501 502 private: 503 static const size_t kErrorMsgSize = 128; 504 505 Zone* zone_; 506 TFBuilder* builder_; 507 const byte* base_; 508 509 SsaEnv* ssa_env_; 510 511 ZoneVector<LocalType> local_type_vec_; // types of local variables. 512 ZoneVector<Value> stack_; // stack of values. 513 ZoneVector<Control> control_; // stack of blocks, loops, and ifs. 514 515 inline bool build() { return builder_ && ssa_env_->go(); } 516 517 void InitSsaEnv() { 518 TFNode* start = nullptr; 519 SsaEnv* ssa_env = reinterpret_cast<SsaEnv*>(zone_->New(sizeof(SsaEnv))); 520 size_t size = sizeof(TFNode*) * EnvironmentCount(); 521 ssa_env->state = SsaEnv::kReached; 522 ssa_env->locals = 523 size > 0 ? reinterpret_cast<TFNode**>(zone_->New(size)) : nullptr; 524 525 if (builder_) { 526 start = builder_->Start(static_cast<int>(sig_->parameter_count() + 1)); 527 // Initialize local variables. 528 uint32_t index = 0; 529 while (index < sig_->parameter_count()) { 530 ssa_env->locals[index] = builder_->Param(index, local_type_vec_[index]); 531 index++; 532 } 533 while (index < local_type_vec_.size()) { 534 LocalType type = local_type_vec_[index]; 535 TFNode* node = DefaultValue(type); 536 while (index < local_type_vec_.size() && 537 local_type_vec_[index] == type) { 538 // Do a whole run of like-typed locals at a time. 539 ssa_env->locals[index++] = node; 540 } 541 } 542 builder_->set_module(module_); 543 } 544 ssa_env->control = start; 545 ssa_env->effect = start; 546 SetEnv("initial", ssa_env); 547 } 548 549 TFNode* DefaultValue(LocalType type) { 550 switch (type) { 551 case kAstI32: 552 return builder_->Int32Constant(0); 553 case kAstI64: 554 return builder_->Int64Constant(0); 555 case kAstF32: 556 return builder_->Float32Constant(0); 557 case kAstF64: 558 return builder_->Float64Constant(0); 559 default: 560 UNREACHABLE(); 561 return nullptr; 562 } 563 } 564 565 char* indentation() { 566 static const int kMaxIndent = 64; 567 static char bytes[kMaxIndent + 1]; 568 for (int i = 0; i < kMaxIndent; ++i) bytes[i] = ' '; 569 bytes[kMaxIndent] = 0; 570 if (stack_.size() < kMaxIndent / 2) { 571 bytes[stack_.size() * 2] = 0; 572 } 573 return bytes; 574 } 575 576 // Decodes the locals declarations, if any, populating {local_type_vec_}. 577 void DecodeLocalDecls() { 578 DCHECK_EQ(0, local_type_vec_.size()); 579 // Initialize {local_type_vec} from signature. 580 if (sig_) { 581 local_type_vec_.reserve(sig_->parameter_count()); 582 for (size_t i = 0; i < sig_->parameter_count(); ++i) { 583 local_type_vec_.push_back(sig_->GetParam(i)); 584 } 585 } 586 // Decode local declarations, if any. 587 uint32_t entries = consume_u32v("local decls count"); 588 while (entries-- > 0 && pc_ < limit_) { 589 uint32_t count = consume_u32v("local count"); 590 byte code = consume_u8("local type"); 591 LocalType type; 592 switch (code) { 593 case kLocalI32: 594 type = kAstI32; 595 break; 596 case kLocalI64: 597 type = kAstI64; 598 break; 599 case kLocalF32: 600 type = kAstF32; 601 break; 602 case kLocalF64: 603 type = kAstF64; 604 break; 605 default: 606 error(pc_ - 1, "invalid local type"); 607 return; 608 } 609 local_type_vec_.insert(local_type_vec_.end(), count, type); 610 } 611 total_locals_ = local_type_vec_.size(); 612 } 613 614 // Decodes the body of a function. 615 void DecodeFunctionBody() { 616 TRACE("wasm-decode %p...%p (module+%d, %d bytes) %s\n", 617 reinterpret_cast<const void*>(start_), 618 reinterpret_cast<const void*>(limit_), baserel(pc_), 619 static_cast<int>(limit_ - start_), builder_ ? "graph building" : ""); 620 621 if (pc_ >= limit_) return; // Nothing to do. 622 623 while (true) { // decoding loop. 624 unsigned len = 1; 625 WasmOpcode opcode = static_cast<WasmOpcode>(*pc_); 626 TRACE(" @%-6d #%02x:%-20s|", startrel(pc_), opcode, 627 WasmOpcodes::ShortOpcodeName(opcode)); 628 629 FunctionSig* sig = WasmOpcodes::Signature(opcode); 630 if (sig) { 631 // Fast case of a simple operator. 632 TFNode* node; 633 switch (sig->parameter_count()) { 634 case 1: { 635 Value val = Pop(0, sig->GetParam(0)); 636 node = BUILD(Unop, opcode, val.node, position()); 637 break; 638 } 639 case 2: { 640 Value rval = Pop(1, sig->GetParam(1)); 641 Value lval = Pop(0, sig->GetParam(0)); 642 node = BUILD(Binop, opcode, lval.node, rval.node, position()); 643 break; 644 } 645 default: 646 UNREACHABLE(); 647 node = nullptr; 648 break; 649 } 650 Push(GetReturnType(sig), node); 651 } else { 652 // Complex bytecode. 653 switch (opcode) { 654 case kExprNop: 655 Push(kAstStmt, nullptr); 656 break; 657 case kExprBlock: { 658 // The break environment is the outer environment. 659 SsaEnv* break_env = ssa_env_; 660 PushBlock(break_env); 661 SetEnv("block:start", Steal(break_env)); 662 break; 663 } 664 case kExprLoop: { 665 // The break environment is the outer environment. 666 SsaEnv* break_env = ssa_env_; 667 PushBlock(break_env); 668 SsaEnv* cont_env = Steal(break_env); 669 // The continue environment is the inner environment. 670 PrepareForLoop(pc_, cont_env); 671 SetEnv("loop:start", Split(cont_env)); 672 ssa_env_->SetNotMerged(); 673 PushLoop(cont_env); 674 break; 675 } 676 case kExprIf: { 677 // Condition on top of stack. Split environments for branches. 678 Value cond = Pop(0, kAstI32); 679 TFNode* if_true = nullptr; 680 TFNode* if_false = nullptr; 681 BUILD(Branch, cond.node, &if_true, &if_false); 682 SsaEnv* end_env = ssa_env_; 683 SsaEnv* false_env = Split(ssa_env_); 684 false_env->control = if_false; 685 SsaEnv* true_env = Steal(ssa_env_); 686 true_env->control = if_true; 687 PushIf(end_env, false_env); 688 SetEnv("if:true", true_env); 689 break; 690 } 691 case kExprElse: { 692 if (control_.empty()) { 693 error(pc_, "else does not match any if"); 694 break; 695 } 696 Control* c = &control_.back(); 697 if (!c->is_if()) { 698 error(pc_, c->pc, "else does not match an if"); 699 break; 700 } 701 if (c->false_env == nullptr) { 702 error(pc_, c->pc, "else already present for if"); 703 break; 704 } 705 Value val = PopUpTo(c->stack_depth); 706 MergeInto(c->end_env, &c->node, &c->type, val); 707 // Switch to environment for false branch. 708 SetEnv("if_else:false", c->false_env); 709 c->false_env = nullptr; // record that an else is already seen 710 break; 711 } 712 case kExprEnd: { 713 if (control_.empty()) { 714 error(pc_, "end does not match any if or block"); 715 break; 716 } 717 const char* name = "block:end"; 718 Control* c = &control_.back(); 719 if (c->is_loop) { 720 // Loops always push control in pairs. 721 control_.pop_back(); 722 c = &control_.back(); 723 name = "loop:end"; 724 } 725 Value val = PopUpTo(c->stack_depth); 726 if (c->is_if()) { 727 if (c->false_env != nullptr) { 728 // End the true branch of a one-armed if. 729 Goto(c->false_env, c->end_env); 730 val = {val.pc, nullptr, kAstStmt}; 731 name = "if:merge"; 732 } else { 733 // End the false branch of a two-armed if. 734 name = "if_else:merge"; 735 } 736 } 737 if (ssa_env_->go()) { 738 MergeInto(c->end_env, &c->node, &c->type, val); 739 } 740 SetEnv(name, c->end_env); 741 stack_.resize(c->stack_depth); 742 Push(c->type, c->node); 743 control_.pop_back(); 744 break; 745 } 746 case kExprSelect: { 747 Value cond = Pop(2, kAstI32); 748 Value fval = Pop(); 749 Value tval = Pop(); 750 if (tval.type == kAstStmt || tval.type != fval.type) { 751 if (tval.type != kAstEnd && fval.type != kAstEnd) { 752 error(pc_, "type mismatch in select"); 753 break; 754 } 755 } 756 if (build()) { 757 DCHECK(tval.type != kAstEnd); 758 DCHECK(fval.type != kAstEnd); 759 DCHECK(cond.type != kAstEnd); 760 TFNode* controls[2]; 761 builder_->Branch(cond.node, &controls[0], &controls[1]); 762 TFNode* merge = builder_->Merge(2, controls); 763 TFNode* vals[2] = {tval.node, fval.node}; 764 TFNode* phi = builder_->Phi(tval.type, 2, vals, merge); 765 Push(tval.type, phi); 766 ssa_env_->control = merge; 767 } else { 768 Push(tval.type, nullptr); 769 } 770 break; 771 } 772 case kExprBr: { 773 BreakDepthOperand operand(this, pc_); 774 Value val = {pc_, nullptr, kAstStmt}; 775 if (operand.arity) val = Pop(); 776 if (Validate(pc_, operand, control_)) { 777 BreakTo(operand.target, val); 778 } 779 len = 1 + operand.length; 780 Push(kAstEnd, nullptr); 781 break; 782 } 783 case kExprBrIf: { 784 BreakDepthOperand operand(this, pc_); 785 Value cond = Pop(operand.arity, kAstI32); 786 Value val = {pc_, nullptr, kAstStmt}; 787 if (operand.arity == 1) val = Pop(); 788 if (Validate(pc_, operand, control_)) { 789 SsaEnv* fenv = ssa_env_; 790 SsaEnv* tenv = Split(fenv); 791 fenv->SetNotMerged(); 792 BUILD(Branch, cond.node, &tenv->control, &fenv->control); 793 ssa_env_ = tenv; 794 BreakTo(operand.target, val); 795 ssa_env_ = fenv; 796 } 797 len = 1 + operand.length; 798 Push(kAstStmt, nullptr); 799 break; 800 } 801 case kExprBrTable: { 802 BranchTableOperand operand(this, pc_); 803 if (Validate(pc_, operand, control_.size())) { 804 Value key = Pop(operand.arity, kAstI32); 805 Value val = {pc_, nullptr, kAstStmt}; 806 if (operand.arity == 1) val = Pop(); 807 if (failed()) break; 808 809 SsaEnv* break_env = ssa_env_; 810 if (operand.table_count > 0) { 811 // Build branches to the various blocks based on the table. 812 TFNode* sw = BUILD(Switch, operand.table_count + 1, key.node); 813 814 SsaEnv* copy = Steal(break_env); 815 ssa_env_ = copy; 816 for (uint32_t i = 0; i < operand.table_count + 1; ++i) { 817 uint16_t target = operand.read_entry(this, i); 818 ssa_env_ = Split(copy); 819 ssa_env_->control = (i == operand.table_count) 820 ? BUILD(IfDefault, sw) 821 : BUILD(IfValue, i, sw); 822 int depth = target; 823 Control* c = &control_[control_.size() - depth - 1]; 824 MergeInto(c->end_env, &c->node, &c->type, val); 825 } 826 } else { 827 // Only a default target. Do the equivalent of br. 828 uint16_t target = operand.read_entry(this, 0); 829 int depth = target; 830 Control* c = &control_[control_.size() - depth - 1]; 831 MergeInto(c->end_env, &c->node, &c->type, val); 832 } 833 // br_table ends the control flow like br. 834 ssa_env_ = break_env; 835 Push(kAstStmt, nullptr); 836 } 837 len = 1 + operand.length; 838 break; 839 } 840 case kExprReturn: { 841 ReturnArityOperand operand(this, pc_); 842 if (operand.arity != sig_->return_count()) { 843 error(pc_, pc_ + 1, "arity mismatch in return"); 844 } 845 DoReturn(); 846 len = 1 + operand.length; 847 break; 848 } 849 case kExprUnreachable: { 850 Push(kAstEnd, BUILD(Unreachable, position())); 851 ssa_env_->Kill(SsaEnv::kControlEnd); 852 break; 853 } 854 case kExprI8Const: { 855 ImmI8Operand operand(this, pc_); 856 Push(kAstI32, BUILD(Int32Constant, operand.value)); 857 len = 1 + operand.length; 858 break; 859 } 860 case kExprI32Const: { 861 ImmI32Operand operand(this, pc_); 862 Push(kAstI32, BUILD(Int32Constant, operand.value)); 863 len = 1 + operand.length; 864 break; 865 } 866 case kExprI64Const: { 867 ImmI64Operand operand(this, pc_); 868 Push(kAstI64, BUILD(Int64Constant, operand.value)); 869 len = 1 + operand.length; 870 break; 871 } 872 case kExprF32Const: { 873 ImmF32Operand operand(this, pc_); 874 Push(kAstF32, BUILD(Float32Constant, operand.value)); 875 len = 1 + operand.length; 876 break; 877 } 878 case kExprF64Const: { 879 ImmF64Operand operand(this, pc_); 880 Push(kAstF64, BUILD(Float64Constant, operand.value)); 881 len = 1 + operand.length; 882 break; 883 } 884 case kExprGetLocal: { 885 LocalIndexOperand operand(this, pc_); 886 if (Validate(pc_, operand)) { 887 if (build()) { 888 Push(operand.type, ssa_env_->locals[operand.index]); 889 } else { 890 Push(operand.type, nullptr); 891 } 892 } 893 len = 1 + operand.length; 894 break; 895 } 896 case kExprSetLocal: { 897 LocalIndexOperand operand(this, pc_); 898 if (Validate(pc_, operand)) { 899 Value val = Pop(0, local_type_vec_[operand.index]); 900 if (ssa_env_->locals) ssa_env_->locals[operand.index] = val.node; 901 Push(val.type, val.node); 902 } 903 len = 1 + operand.length; 904 break; 905 } 906 case kExprLoadGlobal: { 907 GlobalIndexOperand operand(this, pc_); 908 if (Validate(pc_, operand)) { 909 Push(operand.type, BUILD(LoadGlobal, operand.index)); 910 } 911 len = 1 + operand.length; 912 break; 913 } 914 case kExprStoreGlobal: { 915 GlobalIndexOperand operand(this, pc_); 916 if (Validate(pc_, operand)) { 917 Value val = Pop(0, operand.type); 918 BUILD(StoreGlobal, operand.index, val.node); 919 Push(val.type, val.node); 920 } 921 len = 1 + operand.length; 922 break; 923 } 924 case kExprI32LoadMem8S: 925 len = DecodeLoadMem(kAstI32, MachineType::Int8()); 926 break; 927 case kExprI32LoadMem8U: 928 len = DecodeLoadMem(kAstI32, MachineType::Uint8()); 929 break; 930 case kExprI32LoadMem16S: 931 len = DecodeLoadMem(kAstI32, MachineType::Int16()); 932 break; 933 case kExprI32LoadMem16U: 934 len = DecodeLoadMem(kAstI32, MachineType::Uint16()); 935 break; 936 case kExprI32LoadMem: 937 len = DecodeLoadMem(kAstI32, MachineType::Int32()); 938 break; 939 940 case kExprI64LoadMem8S: 941 len = DecodeLoadMem(kAstI64, MachineType::Int8()); 942 break; 943 case kExprI64LoadMem8U: 944 len = DecodeLoadMem(kAstI64, MachineType::Uint8()); 945 break; 946 case kExprI64LoadMem16S: 947 len = DecodeLoadMem(kAstI64, MachineType::Int16()); 948 break; 949 case kExprI64LoadMem16U: 950 len = DecodeLoadMem(kAstI64, MachineType::Uint16()); 951 break; 952 case kExprI64LoadMem32S: 953 len = DecodeLoadMem(kAstI64, MachineType::Int32()); 954 break; 955 case kExprI64LoadMem32U: 956 len = DecodeLoadMem(kAstI64, MachineType::Uint32()); 957 break; 958 case kExprI64LoadMem: 959 len = DecodeLoadMem(kAstI64, MachineType::Int64()); 960 break; 961 case kExprF32LoadMem: 962 len = DecodeLoadMem(kAstF32, MachineType::Float32()); 963 break; 964 case kExprF64LoadMem: 965 len = DecodeLoadMem(kAstF64, MachineType::Float64()); 966 break; 967 case kExprI32StoreMem8: 968 len = DecodeStoreMem(kAstI32, MachineType::Int8()); 969 break; 970 case kExprI32StoreMem16: 971 len = DecodeStoreMem(kAstI32, MachineType::Int16()); 972 break; 973 case kExprI32StoreMem: 974 len = DecodeStoreMem(kAstI32, MachineType::Int32()); 975 break; 976 case kExprI64StoreMem8: 977 len = DecodeStoreMem(kAstI64, MachineType::Int8()); 978 break; 979 case kExprI64StoreMem16: 980 len = DecodeStoreMem(kAstI64, MachineType::Int16()); 981 break; 982 case kExprI64StoreMem32: 983 len = DecodeStoreMem(kAstI64, MachineType::Int32()); 984 break; 985 case kExprI64StoreMem: 986 len = DecodeStoreMem(kAstI64, MachineType::Int64()); 987 break; 988 case kExprF32StoreMem: 989 len = DecodeStoreMem(kAstF32, MachineType::Float32()); 990 break; 991 case kExprF64StoreMem: 992 len = DecodeStoreMem(kAstF64, MachineType::Float64()); 993 break; 994 995 case kExprMemorySize: 996 Push(kAstI32, BUILD(MemSize, 0)); 997 break; 998 case kExprGrowMemory: { 999 Value val = Pop(0, kAstI32); 1000 USE(val); // TODO(titzer): build node for grow memory 1001 Push(kAstI32, BUILD(Int32Constant, 0)); 1002 break; 1003 } 1004 case kExprCallFunction: { 1005 CallFunctionOperand operand(this, pc_); 1006 if (Validate(pc_, operand)) { 1007 TFNode** buffer = PopArgs(operand.sig); 1008 TFNode* call = 1009 BUILD(CallDirect, operand.index, buffer, position()); 1010 Push(GetReturnType(operand.sig), call); 1011 } 1012 len = 1 + operand.length; 1013 break; 1014 } 1015 case kExprCallIndirect: { 1016 CallIndirectOperand operand(this, pc_); 1017 if (Validate(pc_, operand)) { 1018 TFNode** buffer = PopArgs(operand.sig); 1019 Value index = Pop(0, kAstI32); 1020 if (buffer) buffer[0] = index.node; 1021 TFNode* call = 1022 BUILD(CallIndirect, operand.index, buffer, position()); 1023 Push(GetReturnType(operand.sig), call); 1024 } 1025 len = 1 + operand.length; 1026 break; 1027 } 1028 case kExprCallImport: { 1029 CallImportOperand operand(this, pc_); 1030 if (Validate(pc_, operand)) { 1031 TFNode** buffer = PopArgs(operand.sig); 1032 TFNode* call = 1033 BUILD(CallImport, operand.index, buffer, position()); 1034 Push(GetReturnType(operand.sig), call); 1035 } 1036 len = 1 + operand.length; 1037 break; 1038 } 1039 default: 1040 error("Invalid opcode"); 1041 return; 1042 } 1043 } // end complex bytecode 1044 1045 #if DEBUG 1046 if (FLAG_trace_wasm_decoder) { 1047 for (size_t i = 0; i < stack_.size(); ++i) { 1048 Value& val = stack_[i]; 1049 WasmOpcode opcode = static_cast<WasmOpcode>(*val.pc); 1050 PrintF(" %c@%d:%s", WasmOpcodes::ShortNameOf(val.type), 1051 static_cast<int>(val.pc - start_), 1052 WasmOpcodes::ShortOpcodeName(opcode)); 1053 switch (opcode) { 1054 case kExprI32Const: { 1055 ImmI32Operand operand(this, val.pc); 1056 PrintF("[%d]", operand.value); 1057 break; 1058 } 1059 case kExprGetLocal: { 1060 LocalIndexOperand operand(this, val.pc); 1061 PrintF("[%u]", operand.index); 1062 break; 1063 } 1064 case kExprSetLocal: { 1065 LocalIndexOperand operand(this, val.pc); 1066 PrintF("[%u]", operand.index); 1067 break; 1068 } 1069 default: 1070 break; 1071 } 1072 } 1073 PrintF("\n"); 1074 } 1075 #endif 1076 pc_ += len; 1077 if (pc_ >= limit_) { 1078 // End of code reached or exceeded. 1079 if (pc_ > limit_ && ok()) error("Beyond end of code"); 1080 return; 1081 } 1082 } // end decode loop 1083 } // end DecodeFunctionBody() 1084 1085 TFNode** PopArgs(FunctionSig* sig) { 1086 if (build()) { 1087 int count = static_cast<int>(sig->parameter_count()); 1088 TFNode** buffer = builder_->Buffer(count + 1); 1089 buffer[0] = nullptr; // reserved for code object or function index. 1090 for (int i = count - 1; i >= 0; i--) { 1091 buffer[i + 1] = Pop(i, sig->GetParam(i)).node; 1092 } 1093 return buffer; 1094 } else { 1095 int count = static_cast<int>(sig->parameter_count()); 1096 for (int i = count - 1; i >= 0; i--) { 1097 Pop(i, sig->GetParam(i)); 1098 } 1099 return nullptr; 1100 } 1101 } 1102 1103 LocalType GetReturnType(FunctionSig* sig) { 1104 return sig->return_count() == 0 ? kAstStmt : sig->GetReturn(); 1105 } 1106 1107 void PushBlock(SsaEnv* end_env) { 1108 int stack_depth = static_cast<int>(stack_.size()); 1109 control_.push_back( 1110 {pc_, stack_depth, end_env, nullptr, nullptr, kAstEnd, false}); 1111 } 1112 1113 void PushLoop(SsaEnv* end_env) { 1114 int stack_depth = static_cast<int>(stack_.size()); 1115 control_.push_back( 1116 {pc_, stack_depth, end_env, nullptr, nullptr, kAstEnd, true}); 1117 } 1118 1119 void PushIf(SsaEnv* end_env, SsaEnv* false_env) { 1120 int stack_depth = static_cast<int>(stack_.size()); 1121 control_.push_back( 1122 {pc_, stack_depth, end_env, false_env, nullptr, kAstStmt, false}); 1123 } 1124 1125 int DecodeLoadMem(LocalType type, MachineType mem_type) { 1126 MemoryAccessOperand operand(this, pc_); 1127 Value index = Pop(0, kAstI32); 1128 TFNode* node = BUILD(LoadMem, type, mem_type, index.node, operand.offset, 1129 operand.alignment, position()); 1130 Push(type, node); 1131 return 1 + operand.length; 1132 } 1133 1134 int DecodeStoreMem(LocalType type, MachineType mem_type) { 1135 MemoryAccessOperand operand(this, pc_); 1136 Value val = Pop(1, type); 1137 Value index = Pop(0, kAstI32); 1138 BUILD(StoreMem, mem_type, index.node, operand.offset, operand.alignment, 1139 val.node, position()); 1140 Push(type, val.node); 1141 return 1 + operand.length; 1142 } 1143 1144 void DoReturn() { 1145 int count = static_cast<int>(sig_->return_count()); 1146 TFNode** buffer = nullptr; 1147 if (build()) buffer = builder_->Buffer(count); 1148 1149 // Pop return values off the stack in reverse order. 1150 for (int i = count - 1; i >= 0; i--) { 1151 Value val = Pop(i, sig_->GetReturn(i)); 1152 if (buffer) buffer[i] = val.node; 1153 } 1154 1155 Push(kAstEnd, BUILD(Return, count, buffer)); 1156 ssa_env_->Kill(SsaEnv::kControlEnd); 1157 } 1158 1159 void Push(LocalType type, TFNode* node) { 1160 stack_.push_back({pc_, node, type}); 1161 } 1162 1163 const char* SafeOpcodeNameAt(const byte* pc) { 1164 if (pc >= end_) return "<end>"; 1165 return WasmOpcodes::ShortOpcodeName(static_cast<WasmOpcode>(*pc)); 1166 } 1167 1168 Value Pop(int index, LocalType expected) { 1169 Value val = Pop(); 1170 if (val.type != expected) { 1171 if (val.type != kAstEnd) { 1172 error(pc_, val.pc, "%s[%d] expected type %s, found %s of type %s", 1173 SafeOpcodeNameAt(pc_), index, WasmOpcodes::TypeName(expected), 1174 SafeOpcodeNameAt(val.pc), WasmOpcodes::TypeName(val.type)); 1175 } 1176 } 1177 return val; 1178 } 1179 1180 Value Pop() { 1181 size_t limit = control_.empty() ? 0 : control_.back().stack_depth; 1182 if (stack_.size() <= limit) { 1183 Value val = {pc_, nullptr, kAstStmt}; 1184 error(pc_, pc_, "%s found empty stack", SafeOpcodeNameAt(pc_)); 1185 return val; 1186 } 1187 Value val = stack_.back(); 1188 stack_.pop_back(); 1189 return val; 1190 } 1191 1192 Value PopUpTo(int stack_depth) { 1193 if (stack_depth == stack_.size()) { 1194 Value val = {pc_, nullptr, kAstStmt}; 1195 return val; 1196 } else { 1197 DCHECK_LE(stack_depth, static_cast<int>(stack_.size())); 1198 Value val = Pop(); 1199 stack_.resize(stack_depth); 1200 return val; 1201 } 1202 } 1203 1204 int baserel(const byte* ptr) { 1205 return base_ ? static_cast<int>(ptr - base_) : 0; 1206 } 1207 1208 int startrel(const byte* ptr) { return static_cast<int>(ptr - start_); } 1209 1210 void BreakTo(Control* block, Value& val) { 1211 if (block->is_loop) { 1212 // This is the inner loop block, which does not have a value. 1213 Goto(ssa_env_, block->end_env); 1214 } else { 1215 // Merge the value into the production for the block. 1216 MergeInto(block->end_env, &block->node, &block->type, val); 1217 } 1218 } 1219 1220 void MergeInto(SsaEnv* target, TFNode** node, LocalType* type, Value& val) { 1221 if (!ssa_env_->go()) return; 1222 DCHECK_NE(kAstEnd, val.type); 1223 1224 bool first = target->state == SsaEnv::kUnreachable; 1225 Goto(ssa_env_, target); 1226 1227 if (first) { 1228 // first merge to this environment; set the type and the node. 1229 *type = val.type; 1230 *node = val.node; 1231 } else if (val.type == *type && val.type != kAstStmt) { 1232 // merge with the existing value for this block. 1233 *node = CreateOrMergeIntoPhi(*type, target->control, *node, val.node); 1234 } else { 1235 // types don't match, or block is already a stmt. 1236 *type = kAstStmt; 1237 *node = nullptr; 1238 } 1239 } 1240 1241 void SetEnv(const char* reason, SsaEnv* env) { 1242 #if DEBUG 1243 if (FLAG_trace_wasm_decoder) { 1244 char state = 'X'; 1245 if (env) { 1246 switch (env->state) { 1247 case SsaEnv::kReached: 1248 state = 'R'; 1249 break; 1250 case SsaEnv::kUnreachable: 1251 state = 'U'; 1252 break; 1253 case SsaEnv::kMerged: 1254 state = 'M'; 1255 break; 1256 case SsaEnv::kControlEnd: 1257 state = 'E'; 1258 break; 1259 } 1260 } 1261 PrintF(" env = %p, state = %c, reason = %s", static_cast<void*>(env), 1262 state, reason); 1263 if (env && env->control) { 1264 PrintF(", control = "); 1265 compiler::WasmGraphBuilder::PrintDebugName(env->control); 1266 } 1267 PrintF("\n"); 1268 } 1269 #endif 1270 ssa_env_ = env; 1271 if (builder_) { 1272 builder_->set_control_ptr(&env->control); 1273 builder_->set_effect_ptr(&env->effect); 1274 } 1275 } 1276 1277 void Goto(SsaEnv* from, SsaEnv* to) { 1278 DCHECK_NOT_NULL(to); 1279 if (!from->go()) return; 1280 switch (to->state) { 1281 case SsaEnv::kUnreachable: { // Overwrite destination. 1282 to->state = SsaEnv::kReached; 1283 to->locals = from->locals; 1284 to->control = from->control; 1285 to->effect = from->effect; 1286 break; 1287 } 1288 case SsaEnv::kReached: { // Create a new merge. 1289 to->state = SsaEnv::kMerged; 1290 if (!builder_) break; 1291 // Merge control. 1292 TFNode* controls[] = {to->control, from->control}; 1293 TFNode* merge = builder_->Merge(2, controls); 1294 to->control = merge; 1295 // Merge effects. 1296 if (from->effect != to->effect) { 1297 TFNode* effects[] = {to->effect, from->effect, merge}; 1298 to->effect = builder_->EffectPhi(2, effects, merge); 1299 } 1300 // Merge SSA values. 1301 for (int i = EnvironmentCount() - 1; i >= 0; i--) { 1302 TFNode* a = to->locals[i]; 1303 TFNode* b = from->locals[i]; 1304 if (a != b) { 1305 TFNode* vals[] = {a, b}; 1306 to->locals[i] = builder_->Phi(local_type_vec_[i], 2, vals, merge); 1307 } 1308 } 1309 break; 1310 } 1311 case SsaEnv::kMerged: { 1312 if (!builder_) break; 1313 TFNode* merge = to->control; 1314 // Extend the existing merge. 1315 builder_->AppendToMerge(merge, from->control); 1316 // Merge effects. 1317 if (builder_->IsPhiWithMerge(to->effect, merge)) { 1318 builder_->AppendToPhi(to->effect, from->effect); 1319 } else if (to->effect != from->effect) { 1320 uint32_t count = builder_->InputCount(merge); 1321 TFNode** effects = builder_->Buffer(count); 1322 for (uint32_t j = 0; j < count - 1; j++) { 1323 effects[j] = to->effect; 1324 } 1325 effects[count - 1] = from->effect; 1326 to->effect = builder_->EffectPhi(count, effects, merge); 1327 } 1328 // Merge locals. 1329 for (int i = EnvironmentCount() - 1; i >= 0; i--) { 1330 TFNode* tnode = to->locals[i]; 1331 TFNode* fnode = from->locals[i]; 1332 if (builder_->IsPhiWithMerge(tnode, merge)) { 1333 builder_->AppendToPhi(tnode, fnode); 1334 } else if (tnode != fnode) { 1335 uint32_t count = builder_->InputCount(merge); 1336 TFNode** vals = builder_->Buffer(count); 1337 for (uint32_t j = 0; j < count - 1; j++) { 1338 vals[j] = tnode; 1339 } 1340 vals[count - 1] = fnode; 1341 to->locals[i] = 1342 builder_->Phi(local_type_vec_[i], count, vals, merge); 1343 } 1344 } 1345 break; 1346 } 1347 default: 1348 UNREACHABLE(); 1349 } 1350 return from->Kill(); 1351 } 1352 1353 TFNode* CreateOrMergeIntoPhi(LocalType type, TFNode* merge, TFNode* tnode, 1354 TFNode* fnode) { 1355 if (builder_->IsPhiWithMerge(tnode, merge)) { 1356 builder_->AppendToPhi(tnode, fnode); 1357 } else if (tnode != fnode) { 1358 uint32_t count = builder_->InputCount(merge); 1359 TFNode** vals = builder_->Buffer(count); 1360 for (uint32_t j = 0; j < count - 1; j++) vals[j] = tnode; 1361 vals[count - 1] = fnode; 1362 return builder_->Phi(type, count, vals, merge); 1363 } 1364 return tnode; 1365 } 1366 1367 void PrepareForLoop(const byte* pc, SsaEnv* env) { 1368 if (!env->go()) return; 1369 env->state = SsaEnv::kMerged; 1370 if (!builder_) return; 1371 1372 env->control = builder_->Loop(env->control); 1373 env->effect = builder_->EffectPhi(1, &env->effect, env->control); 1374 builder_->Terminate(env->effect, env->control); 1375 if (FLAG_wasm_loop_assignment_analysis) { 1376 BitVector* assigned = AnalyzeLoopAssignment(pc); 1377 if (assigned != nullptr) { 1378 // Only introduce phis for variables assigned in this loop. 1379 for (int i = EnvironmentCount() - 1; i >= 0; i--) { 1380 if (!assigned->Contains(i)) continue; 1381 env->locals[i] = builder_->Phi(local_type_vec_[i], 1, &env->locals[i], 1382 env->control); 1383 } 1384 return; 1385 } 1386 } 1387 1388 // Conservatively introduce phis for all local variables. 1389 for (int i = EnvironmentCount() - 1; i >= 0; i--) { 1390 env->locals[i] = 1391 builder_->Phi(local_type_vec_[i], 1, &env->locals[i], env->control); 1392 } 1393 } 1394 1395 // Create a complete copy of the {from}. 1396 SsaEnv* Split(SsaEnv* from) { 1397 DCHECK_NOT_NULL(from); 1398 SsaEnv* result = reinterpret_cast<SsaEnv*>(zone_->New(sizeof(SsaEnv))); 1399 size_t size = sizeof(TFNode*) * EnvironmentCount(); 1400 result->control = from->control; 1401 result->effect = from->effect; 1402 1403 if (from->go()) { 1404 result->state = SsaEnv::kReached; 1405 result->locals = 1406 size > 0 ? reinterpret_cast<TFNode**>(zone_->New(size)) : nullptr; 1407 memcpy(result->locals, from->locals, size); 1408 } else { 1409 result->state = SsaEnv::kUnreachable; 1410 result->locals = nullptr; 1411 } 1412 1413 return result; 1414 } 1415 1416 // Create a copy of {from} that steals its state and leaves {from} 1417 // unreachable. 1418 SsaEnv* Steal(SsaEnv* from) { 1419 DCHECK_NOT_NULL(from); 1420 if (!from->go()) return UnreachableEnv(); 1421 SsaEnv* result = reinterpret_cast<SsaEnv*>(zone_->New(sizeof(SsaEnv))); 1422 result->state = SsaEnv::kReached; 1423 result->locals = from->locals; 1424 result->control = from->control; 1425 result->effect = from->effect; 1426 from->Kill(SsaEnv::kUnreachable); 1427 return result; 1428 } 1429 1430 // Create an unreachable environment. 1431 SsaEnv* UnreachableEnv() { 1432 SsaEnv* result = reinterpret_cast<SsaEnv*>(zone_->New(sizeof(SsaEnv))); 1433 result->state = SsaEnv::kUnreachable; 1434 result->control = nullptr; 1435 result->effect = nullptr; 1436 result->locals = nullptr; 1437 return result; 1438 } 1439 1440 int EnvironmentCount() { 1441 if (builder_) return static_cast<int>(local_type_vec_.size()); 1442 return 0; // if we aren't building a graph, don't bother with SSA renaming. 1443 } 1444 1445 virtual void onFirstError() { 1446 limit_ = start_; // Terminate decoding loop. 1447 builder_ = nullptr; // Don't build any more nodes. 1448 TRACE(" !%s\n", error_msg_.get()); 1449 } 1450 BitVector* AnalyzeLoopAssignment(const byte* pc) { 1451 if (pc >= limit_) return nullptr; 1452 if (*pc != kExprLoop) return nullptr; 1453 1454 BitVector* assigned = 1455 new (zone_) BitVector(static_cast<int>(local_type_vec_.size()), zone_); 1456 int depth = 0; 1457 // Iteratively process all AST nodes nested inside the loop. 1458 while (pc < limit_ && ok()) { 1459 WasmOpcode opcode = static_cast<WasmOpcode>(*pc); 1460 unsigned length = 1; 1461 switch (opcode) { 1462 case kExprLoop: 1463 case kExprIf: 1464 case kExprBlock: 1465 depth++; 1466 DCHECK_EQ(1, OpcodeLength(pc)); 1467 break; 1468 case kExprSetLocal: { 1469 LocalIndexOperand operand(this, pc); 1470 if (assigned->length() > 0 && 1471 static_cast<int>(operand.index) < assigned->length()) { 1472 // Unverified code might have an out-of-bounds index. 1473 assigned->Add(operand.index); 1474 } 1475 length = 1 + operand.length; 1476 break; 1477 } 1478 case kExprEnd: 1479 depth--; 1480 break; 1481 default: 1482 length = OpcodeLength(pc); 1483 break; 1484 } 1485 if (depth <= 0) break; 1486 pc += length; 1487 } 1488 return ok() ? assigned : nullptr; 1489 } 1490 1491 inline wasm::WasmCodePosition position() { 1492 int offset = static_cast<int>(pc_ - start_); 1493 DCHECK_EQ(pc_ - start_, offset); // overflows cannot happen 1494 return offset; 1495 } 1496 }; 1497 1498 bool DecodeLocalDecls(AstLocalDecls& decls, const byte* start, 1499 const byte* end) { 1500 base::AccountingAllocator allocator; 1501 Zone tmp(&allocator); 1502 FunctionBody body = {nullptr, nullptr, nullptr, start, end}; 1503 SR_WasmDecoder decoder(&tmp, nullptr, body); 1504 return decoder.DecodeLocalDecls(decls); 1505 } 1506 1507 TreeResult VerifyWasmCode(base::AccountingAllocator* allocator, 1508 FunctionBody& body) { 1509 Zone zone(allocator); 1510 SR_WasmDecoder decoder(&zone, nullptr, body); 1511 decoder.Decode(); 1512 return decoder.toResult<Tree*>(nullptr); 1513 } 1514 1515 TreeResult BuildTFGraph(base::AccountingAllocator* allocator, 1516 TFBuilder* builder, FunctionBody& body) { 1517 Zone zone(allocator); 1518 SR_WasmDecoder decoder(&zone, builder, body); 1519 decoder.Decode(); 1520 return decoder.toResult<Tree*>(nullptr); 1521 } 1522 1523 std::ostream& operator<<(std::ostream& os, const Tree& tree) { 1524 if (tree.pc == nullptr) { 1525 os << "null"; 1526 return os; 1527 } 1528 PrintF("%s", WasmOpcodes::OpcodeName(tree.opcode())); 1529 if (tree.count > 0) os << "("; 1530 for (uint32_t i = 0; i < tree.count; ++i) { 1531 if (i > 0) os << ", "; 1532 os << *tree.children[i]; 1533 } 1534 if (tree.count > 0) os << ")"; 1535 return os; 1536 } 1537 1538 unsigned OpcodeLength(const byte* pc, const byte* end) { 1539 WasmDecoder decoder(nullptr, nullptr, pc, end); 1540 return decoder.OpcodeLength(pc); 1541 } 1542 1543 unsigned OpcodeArity(const byte* pc, const byte* end) { 1544 WasmDecoder decoder(nullptr, nullptr, pc, end); 1545 return decoder.OpcodeArity(pc); 1546 } 1547 1548 void PrintAstForDebugging(const byte* start, const byte* end) { 1549 base::AccountingAllocator allocator; 1550 OFStream os(stdout); 1551 PrintAst(&allocator, FunctionBodyForTesting(start, end), os, nullptr); 1552 } 1553 1554 bool PrintAst(base::AccountingAllocator* allocator, const FunctionBody& body, 1555 std::ostream& os, 1556 std::vector<std::tuple<uint32_t, int, int>>* offset_table) { 1557 Zone zone(allocator); 1558 SR_WasmDecoder decoder(&zone, nullptr, body); 1559 int line_nr = 0; 1560 1561 // Print the function signature. 1562 if (body.sig) { 1563 os << "// signature: " << *body.sig << std::endl; 1564 ++line_nr; 1565 } 1566 1567 // Print the local declarations. 1568 AstLocalDecls decls(&zone); 1569 decoder.DecodeLocalDecls(decls); 1570 const byte* pc = decoder.pc(); 1571 if (body.start != decoder.pc()) { 1572 os << "// locals: "; 1573 for (auto p : decls.local_types) { 1574 LocalType type = p.first; 1575 uint32_t count = p.second; 1576 os << " " << count << " " << WasmOpcodes::TypeName(type); 1577 } 1578 os << std::endl; 1579 1580 for (const byte* locals = body.start; locals < pc; locals++) { 1581 os << (locals == body.start ? "0x" : " 0x") << AsHex(*locals, 2) << ","; 1582 } 1583 os << std::endl; 1584 ++line_nr; 1585 } 1586 1587 os << "// body: " << std::endl; 1588 ++line_nr; 1589 unsigned control_depth = 0; 1590 while (pc < body.end) { 1591 unsigned length = decoder.OpcodeLength(pc); 1592 1593 WasmOpcode opcode = static_cast<WasmOpcode>(*pc); 1594 if (opcode == kExprElse) control_depth--; 1595 1596 int num_whitespaces = control_depth < 32 ? 2 * control_depth : 64; 1597 if (offset_table) { 1598 offset_table->push_back( 1599 std::make_tuple(pc - body.start, line_nr, num_whitespaces)); 1600 } 1601 1602 // 64 whitespaces 1603 const char* padding = 1604 " "; 1605 os.write(padding, num_whitespaces); 1606 os << "k" << WasmOpcodes::OpcodeName(opcode) << ","; 1607 1608 for (size_t i = 1; i < length; ++i) { 1609 os << " " << AsHex(pc[i], 2) << ","; 1610 } 1611 1612 switch (opcode) { 1613 case kExprIf: 1614 case kExprElse: 1615 case kExprLoop: 1616 case kExprBlock: 1617 os << " // @" << static_cast<int>(pc - body.start); 1618 control_depth++; 1619 break; 1620 case kExprEnd: 1621 os << " // @" << static_cast<int>(pc - body.start); 1622 control_depth--; 1623 break; 1624 case kExprBr: { 1625 BreakDepthOperand operand(&decoder, pc); 1626 os << " // arity=" << operand.arity << " depth=" << operand.depth; 1627 break; 1628 } 1629 case kExprBrIf: { 1630 BreakDepthOperand operand(&decoder, pc); 1631 os << " // arity=" << operand.arity << " depth" << operand.depth; 1632 break; 1633 } 1634 case kExprBrTable: { 1635 BranchTableOperand operand(&decoder, pc); 1636 os << " // arity=" << operand.arity 1637 << " entries=" << operand.table_count; 1638 break; 1639 } 1640 case kExprCallIndirect: { 1641 CallIndirectOperand operand(&decoder, pc); 1642 if (decoder.Complete(pc, operand)) { 1643 os << " // sig #" << operand.index << ": " << *operand.sig; 1644 } else { 1645 os << " // arity=" << operand.arity << " sig #" << operand.index; 1646 } 1647 break; 1648 } 1649 case kExprCallImport: { 1650 CallImportOperand operand(&decoder, pc); 1651 if (decoder.Complete(pc, operand)) { 1652 os << " // import #" << operand.index << ": " << *operand.sig; 1653 } else { 1654 os << " // arity=" << operand.arity << " import #" << operand.index; 1655 } 1656 break; 1657 } 1658 case kExprCallFunction: { 1659 CallFunctionOperand operand(&decoder, pc); 1660 if (decoder.Complete(pc, operand)) { 1661 os << " // function #" << operand.index << ": " << *operand.sig; 1662 } else { 1663 os << " // arity=" << operand.arity << " function #" << operand.index; 1664 } 1665 break; 1666 } 1667 case kExprReturn: { 1668 ReturnArityOperand operand(&decoder, pc); 1669 os << " // arity=" << operand.arity; 1670 break; 1671 } 1672 default: 1673 break; 1674 } 1675 1676 pc += length; 1677 os << std::endl; 1678 ++line_nr; 1679 } 1680 1681 return decoder.ok(); 1682 } 1683 1684 BitVector* AnalyzeLoopAssignmentForTesting(Zone* zone, size_t num_locals, 1685 const byte* start, const byte* end) { 1686 FunctionBody body = {nullptr, nullptr, nullptr, start, end}; 1687 SR_WasmDecoder decoder(zone, nullptr, body); 1688 return decoder.AnalyzeLoopAssignmentForTesting(start, num_locals); 1689 } 1690 1691 } // namespace wasm 1692 } // namespace internal 1693 } // namespace v8 1694
