lib/Object/WasmObjectFile.cpp

   1 //===- WasmObjectFile.cpp - Wasm object file implementation ---------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "llvm/ADT/ArrayRef.h"
  10 #include "llvm/ADT/DenseSet.h"
  11 #include "llvm/ADT/STLExtras.h"
  12 #include "llvm/ADT/SmallSet.h"
  13 #include "llvm/ADT/StringRef.h"
  14 #include "llvm/ADT/StringSet.h"
  15 #include "llvm/ADT/Triple.h"
  16 #include "llvm/BinaryFormat/Wasm.h"
  17 #include "llvm/MC/SubtargetFeature.h"
  18 #include "llvm/Object/Binary.h"
  19 #include "llvm/Object/Error.h"
  20 #include "llvm/Object/ObjectFile.h"
  21 #include "llvm/Object/SymbolicFile.h"
  22 #include "llvm/Object/Wasm.h"
  23 #include "llvm/Support/Endian.h"
  24 #include "llvm/Support/Error.h"
  25 #include "llvm/Support/ErrorHandling.h"
  26 #include "llvm/Support/LEB128.h"
  27 #include "llvm/Support/ScopedPrinter.h"
  28 #include <algorithm>
  29 #include <cassert>
  30 #include <cstdint>
  31 #include <cstring>
  32 #include <system_error>
  33
  34 #define DEBUG_TYPE "wasm-object"
  35
  36 using namespace llvm;
  37 using namespace object;
  38
  39 void WasmSymbol::print(raw_ostream &Out) const {
  40   Out << "Name=" << Info.Name
  41       << ", Kind=" << toString(wasm::WasmSymbolType(Info.Kind))
  42       << ", Flags=" << Info.Flags;
  43   if (!isTypeData()) {
  44     Out << ", ElemIndex=" << Info.ElementIndex;
  45   } else if (isDefined()) {
  46     Out << ", Segment=" << Info.DataRef.Segment;
  47     Out << ", Offset=" << Info.DataRef.Offset;
  48     Out << ", Size=" << Info.DataRef.Size;
  49   }
  50 }
  51
  52 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
  53 LLVM_DUMP_METHOD void WasmSymbol::dump() const { print(dbgs()); }
  54 #endif
  55
  56 Expected<std::unique_ptr<WasmObjectFile>>
  57 ObjectFile::createWasmObjectFile(MemoryBufferRef Buffer) {
  58   Error Err = Error::success();
  59   auto ObjectFile = llvm::make_unique<WasmObjectFile>(Buffer, Err);
  60   if (Err)
  61     return std::move(Err);
  62
  63   return std::move(ObjectFile);
  64 }
  65
  66 #define VARINT7_MAX ((1 << 7) - 1)
  67 #define VARINT7_MIN (-(1 << 7))
  68 #define VARUINT7_MAX (1 << 7)
  69 #define VARUINT1_MAX (1)
  70
  71 static uint8_t readUint8(WasmObjectFile::ReadContext &Ctx) {
  72   if (Ctx.Ptr == Ctx.End)
  73     report_fatal_error("EOF while reading uint8");
  74   return *Ctx.Ptr++;
  75 }
  76
  77 static uint32_t readUint32(WasmObjectFile::ReadContext &Ctx) {
  78   if (Ctx.Ptr + 4 > Ctx.End)
  79     report_fatal_error("EOF while reading uint32");
  80   uint32_t Result = support::endian::read32le(Ctx.Ptr);
  81   Ctx.Ptr += 4;
  82   return Result;
  83 }
  84
  85 static int32_t readFloat32(WasmObjectFile::ReadContext &Ctx) {
  86   if (Ctx.Ptr + 4 > Ctx.End)
  87     report_fatal_error("EOF while reading float64");
  88   int32_t Result = 0;
  89   memcpy(&Result, Ctx.Ptr, sizeof(Result));
  90   Ctx.Ptr += sizeof(Result);
  91   return Result;
  92 }
  93
  94 static int64_t readFloat64(WasmObjectFile::ReadContext &Ctx) {
  95   if (Ctx.Ptr + 8 > Ctx.End)
  96     report_fatal_error("EOF while reading float64");
  97   int64_t Result = 0;
  98   memcpy(&Result, Ctx.Ptr, sizeof(Result));
  99   Ctx.Ptr += sizeof(Result);
 100   return Result;
 101 }
 102
 103 static uint64_t readULEB128(WasmObjectFile::ReadContext &Ctx) {
 104   unsigned Count;
 105   const char *Error = nullptr;
 106   uint64_t Result = decodeULEB128(Ctx.Ptr, &Count, Ctx.End, &Error);
 107   if (Error)
 108     report_fatal_error(Error);
 109   Ctx.Ptr += Count;
 110   return Result;
 111 }
 112
 113 static StringRef readString(WasmObjectFile::ReadContext &Ctx) {
 114   uint32_t StringLen = readULEB128(Ctx);
 115   if (Ctx.Ptr + StringLen > Ctx.End)
 116     report_fatal_error("EOF while reading string");
 117   StringRef Return =
 118       StringRef(reinterpret_cast<const char *>(Ctx.Ptr), StringLen);
 119   Ctx.Ptr += StringLen;
 120   return Return;
 121 }
 122
 123 static int64_t readLEB128(WasmObjectFile::ReadContext &Ctx) {
 124   unsigned Count;
 125   const char *Error = nullptr;
 126   uint64_t Result = decodeSLEB128(Ctx.Ptr, &Count, Ctx.End, &Error);
 127   if (Error)
 128     report_fatal_error(Error);
 129   Ctx.Ptr += Count;
 130   return Result;
 131 }
 132
 133 static uint8_t readVaruint1(WasmObjectFile::ReadContext &Ctx) {
 134   int64_t result = readLEB128(Ctx);
 135   if (result > VARUINT1_MAX || result < 0)
 136     report_fatal_error("LEB is outside Varuint1 range");
 137   return result;
 138 }
 139
 140 static int32_t readVarint32(WasmObjectFile::ReadContext &Ctx) {
 141   int64_t result = readLEB128(Ctx);
 142   if (result > INT32_MAX || result < INT32_MIN)
 143     report_fatal_error("LEB is outside Varint32 range");
 144   return result;
 145 }
 146
 147 static uint32_t readVaruint32(WasmObjectFile::ReadContext &Ctx) {
 148   uint64_t result = readULEB128(Ctx);
 149   if (result > UINT32_MAX)
 150     report_fatal_error("LEB is outside Varuint32 range");
 151   return result;
 152 }
 153
 154 static int64_t readVarint64(WasmObjectFile::ReadContext &Ctx) {
 155   return readLEB128(Ctx);
 156 }
 157
 158 static uint8_t readOpcode(WasmObjectFile::ReadContext &Ctx) {
 159   return readUint8(Ctx);
 160 }
 161
 162 static Error readInitExpr(wasm::WasmInitExpr &Expr,
 163                           WasmObjectFile::ReadContext &Ctx) {
 164   Expr.Opcode = readOpcode(Ctx);
 165
 166   switch (Expr.Opcode) {
 167   case wasm::WASM_OPCODE_I32_CONST:
 168     Expr.Value.Int32 = readVarint32(Ctx);
 169     break;
 170   case wasm::WASM_OPCODE_I64_CONST:
 171     Expr.Value.Int64 = readVarint64(Ctx);
 172     break;
 173   case wasm::WASM_OPCODE_F32_CONST:
 174     Expr.Value.Float32 = readFloat32(Ctx);
 175     break;
 176   case wasm::WASM_OPCODE_F64_CONST:
 177     Expr.Value.Float64 = readFloat64(Ctx);
 178     break;
 179   case wasm::WASM_OPCODE_GLOBAL_GET:
 180     Expr.Value.Global = readULEB128(Ctx);
 181     break;
 182   default:
 183     return make_error<GenericBinaryError>("Invalid opcode in init_expr",
 184                                           object_error::parse_failed);
 185   }
 186
 187   uint8_t EndOpcode = readOpcode(Ctx);
 188   if (EndOpcode != wasm::WASM_OPCODE_END) {
 189     return make_error<GenericBinaryError>("Invalid init_expr",
 190                                           object_error::parse_failed);
 191   }
 192   return Error::success();
 193 }
 194
 195 static wasm::WasmLimits readLimits(WasmObjectFile::ReadContext &Ctx) {
 196   wasm::WasmLimits Result;
 197   Result.Flags = readVaruint32(Ctx);
 198   Result.Initial = readVaruint32(Ctx);
 199   if (Result.Flags & wasm::WASM_LIMITS_FLAG_HAS_MAX)
 200     Result.Maximum = readVaruint32(Ctx);
 201   return Result;
 202 }
 203
 204 static wasm::WasmTable readTable(WasmObjectFile::ReadContext &Ctx) {
 205   wasm::WasmTable Table;
 206   Table.ElemType = readUint8(Ctx);
 207   Table.Limits = readLimits(Ctx);
 208   return Table;
 209 }
 210
 211 static Error readSection(WasmSection &Section, WasmObjectFile::ReadContext &Ctx,
 212                          WasmSectionOrderChecker &Checker) {
 213   Section.Offset = Ctx.Ptr - Ctx.Start;
 214   Section.Type = readUint8(Ctx);
 215   LLVM_DEBUG(dbgs() << "readSection type=" << Section.Type << "\n");
 216   uint32_t Size = readVaruint32(Ctx);
 217   if (Size == 0)
 218     return make_error<StringError>("Zero length section",
 219                                    object_error::parse_failed);
 220   if (Ctx.Ptr + Size > Ctx.End)
 221     return make_error<StringError>("Section too large",
 222                                    object_error::parse_failed);
 223   if (Section.Type == wasm::WASM_SEC_CUSTOM) {
 224     WasmObjectFile::ReadContext SectionCtx;
 225     SectionCtx.Start = Ctx.Ptr;
 226     SectionCtx.Ptr = Ctx.Ptr;
 227     SectionCtx.End = Ctx.Ptr + Size;
 228
 229     Section.Name = readString(SectionCtx);
 230
 231     uint32_t SectionNameSize = SectionCtx.Ptr - SectionCtx.Start;
 232     Ctx.Ptr += SectionNameSize;
 233     Size -= SectionNameSize;
 234   }
 235
 236   if (!Checker.isValidSectionOrder(Section.Type, Section.Name)) {
 237     return make_error<StringError>("Out of order section type: " +
 238                                        llvm::to_string(Section.Type),
 239                                    object_error::parse_failed);
 240   }
 241
 242   Section.Content = ArrayRef<uint8_t>(Ctx.Ptr, Size);
 243   Ctx.Ptr += Size;
 244   return Error::success();
 245 }
 246
 247 WasmObjectFile::WasmObjectFile(MemoryBufferRef Buffer, Error &Err)
 248     : ObjectFile(Binary::ID_Wasm, Buffer) {
 249   ErrorAsOutParameter ErrAsOutParam(&Err);
 250   Header.Magic = getData().substr(0, 4);
 251   if (Header.Magic != StringRef("\0asm", 4)) {
 252     Err =
 253         make_error<StringError>("Bad magic number", object_error::parse_failed);
 254     return;
 255   }
 256
 257   ReadContext Ctx;
 258   Ctx.Start = getPtr(0);
 259   Ctx.Ptr = Ctx.Start + 4;
 260   Ctx.End = Ctx.Start + getData().size();
 261
 262   if (Ctx.Ptr + 4 > Ctx.End) {
 263     Err = make_error<StringError>("Missing version number",
 264                                   object_error::parse_failed);
 265     return;
 266   }
 267
 268   Header.Version = readUint32(Ctx);
 269   if (Header.Version != wasm::WasmVersion) {
 270     Err = make_error<StringError>("Bad version number",
 271                                   object_error::parse_failed);
 272     return;
 273   }
 274
 275   WasmSection Sec;
 276   WasmSectionOrderChecker Checker;
 277   while (Ctx.Ptr < Ctx.End) {
 278     if ((Err = readSection(Sec, Ctx, Checker)))
 279       return;
 280     if ((Err = parseSection(Sec)))
 281       return;
 282
 283     Sections.push_back(Sec);
 284   }
 285 }
 286
 287 Error WasmObjectFile::parseSection(WasmSection &Sec) {
 288   ReadContext Ctx;
 289   Ctx.Start = Sec.Content.data();
 290   Ctx.End = Ctx.Start + Sec.Content.size();
 291   Ctx.Ptr = Ctx.Start;
 292   switch (Sec.Type) {
 293   case wasm::WASM_SEC_CUSTOM:
 294     return parseCustomSection(Sec, Ctx);
 295   case wasm::WASM_SEC_TYPE:
 296     return parseTypeSection(Ctx);
 297   case wasm::WASM_SEC_IMPORT:
 298     return parseImportSection(Ctx);
 299   case wasm::WASM_SEC_FUNCTION:
 300     return parseFunctionSection(Ctx);
 301   case wasm::WASM_SEC_TABLE:
 302     return parseTableSection(Ctx);
 303   case wasm::WASM_SEC_MEMORY:
 304     return parseMemorySection(Ctx);
 305   case wasm::WASM_SEC_GLOBAL:
 306     return parseGlobalSection(Ctx);
 307   case wasm::WASM_SEC_EVENT:
 308     return parseEventSection(Ctx);
 309   case wasm::WASM_SEC_EXPORT:
 310     return parseExportSection(Ctx);
 311   case wasm::WASM_SEC_START:
 312     return parseStartSection(Ctx);
 313   case wasm::WASM_SEC_ELEM:
 314     return parseElemSection(Ctx);
 315   case wasm::WASM_SEC_CODE:
 316     return parseCodeSection(Ctx);
 317   case wasm::WASM_SEC_DATA:
 318     return parseDataSection(Ctx);
 319   default:
 320     return make_error<GenericBinaryError>("Bad section type",
 321                                           object_error::parse_failed);
 322   }
 323 }
 324
 325 Error WasmObjectFile::parseDylinkSection(ReadContext &Ctx) {
 326   // See https://github.com/WebAssembly/tool-conventions/blob/master/DynamicLinking.md
 327   DylinkInfo.MemorySize = readVaruint32(Ctx);
 328   DylinkInfo.MemoryAlignment = readVaruint32(Ctx);
 329   DylinkInfo.TableSize = readVaruint32(Ctx);
 330   DylinkInfo.TableAlignment = readVaruint32(Ctx);
 331   uint32_t Count = readVaruint32(Ctx);
 332   while (Count--) {
 333     DylinkInfo.Needed.push_back(readString(Ctx));
 334   }
 335   if (Ctx.Ptr != Ctx.End)
 336     return make_error<GenericBinaryError>("dylink section ended prematurely",
 337                                           object_error::parse_failed);
 338   return Error::success();
 339 }
 340
 341 Error WasmObjectFile::parseNameSection(ReadContext &Ctx) {
 342   llvm::DenseSet<uint64_t> Seen;
 343   if (Functions.size() != FunctionTypes.size()) {
 344     return make_error<GenericBinaryError>("Names must come after code section",
 345                                           object_error::parse_failed);
 346   }
 347
 348   while (Ctx.Ptr < Ctx.End) {
 349     uint8_t Type = readUint8(Ctx);
 350     uint32_t Size = readVaruint32(Ctx);
 351     const uint8_t *SubSectionEnd = Ctx.Ptr + Size;
 352     switch (Type) {
 353     case wasm::WASM_NAMES_FUNCTION: {
 354       uint32_t Count = readVaruint32(Ctx);
 355       while (Count--) {
 356         uint32_t Index = readVaruint32(Ctx);
 357         if (!Seen.insert(Index).second)
 358           return make_error<GenericBinaryError>("Function named more than once",
 359                                                 object_error::parse_failed);
 360         StringRef Name = readString(Ctx);
 361         if (!isValidFunctionIndex(Index) || Name.empty())
 362           return make_error<GenericBinaryError>("Invalid name entry",
 363                                                 object_error::parse_failed);
 364         DebugNames.push_back(wasm::WasmFunctionName{Index, Name});
 365         if (isDefinedFunctionIndex(Index))
 366           getDefinedFunction(Index).DebugName = Name;
 367       }
 368       break;
 369     }
 370     // Ignore local names for now
 371     case wasm::WASM_NAMES_LOCAL:
 372     default:
 373       Ctx.Ptr += Size;
 374       break;
 375     }
 376     if (Ctx.Ptr != SubSectionEnd)
 377       return make_error<GenericBinaryError>(
 378           "Name sub-section ended prematurely", object_error::parse_failed);
 379   }
 380
 381   if (Ctx.Ptr != Ctx.End)
 382     return make_error<GenericBinaryError>("Name section ended prematurely",
 383                                           object_error::parse_failed);
 384   return Error::success();
 385 }
 386
 387 Error WasmObjectFile::parseLinkingSection(ReadContext &Ctx) {
 388   HasLinkingSection = true;
 389   if (Functions.size() != FunctionTypes.size()) {
 390     return make_error<GenericBinaryError>(
 391         "Linking data must come after code section",
 392         object_error::parse_failed);
 393   }
 394
 395   LinkingData.Version = readVaruint32(Ctx);
 396   if (LinkingData.Version != wasm::WasmMetadataVersion) {
 397     return make_error<GenericBinaryError>(
 398         "Unexpected metadata version: " + Twine(LinkingData.Version) +
 399             " (Expected: " + Twine(wasm::WasmMetadataVersion) + ")",
 400         object_error::parse_failed);
 401   }
 402
 403   const uint8_t *OrigEnd = Ctx.End;
 404   while (Ctx.Ptr < OrigEnd) {
 405     Ctx.End = OrigEnd;
 406     uint8_t Type = readUint8(Ctx);
 407     uint32_t Size = readVaruint32(Ctx);
 408     LLVM_DEBUG(dbgs() << "readSubsection type=" << int(Type) << " size=" << Size
 409                       << "\n");
 410     Ctx.End = Ctx.Ptr + Size;
 411     switch (Type) {
 412     case wasm::WASM_SYMBOL_TABLE:
 413       if (Error Err = parseLinkingSectionSymtab(Ctx))
 414         return Err;
 415       break;
 416     case wasm::WASM_SEGMENT_INFO: {
 417       uint32_t Count = readVaruint32(Ctx);
 418       if (Count > DataSegments.size())
 419         return make_error<GenericBinaryError>("Too many segment names",
 420                                               object_error::parse_failed);
 421       for (uint32_t i = 0; i < Count; i++) {
 422         DataSegments[i].Data.Name = readString(Ctx);
 423         DataSegments[i].Data.Alignment = readVaruint32(Ctx);
 424         DataSegments[i].Data.Flags = readVaruint32(Ctx);
 425       }
 426       break;
 427     }
 428     case wasm::WASM_INIT_FUNCS: {
 429       uint32_t Count = readVaruint32(Ctx);
 430       LinkingData.InitFunctions.reserve(Count);
 431       for (uint32_t i = 0; i < Count; i++) {
 432         wasm::WasmInitFunc Init;
 433         Init.Priority = readVaruint32(Ctx);
 434         Init.Symbol = readVaruint32(Ctx);
 435         if (!isValidFunctionSymbol(Init.Symbol))
 436           return make_error<GenericBinaryError>("Invalid function symbol: " +
 437                                                     Twine(Init.Symbol),
 438                                                 object_error::parse_failed);
 439         LinkingData.InitFunctions.emplace_back(Init);
 440       }
 441       break;
 442     }
 443     case wasm::WASM_COMDAT_INFO:
 444       if (Error Err = parseLinkingSectionComdat(Ctx))
 445         return Err;
 446       break;
 447     default:
 448       Ctx.Ptr += Size;
 449       break;
 450     }
 451     if (Ctx.Ptr != Ctx.End)
 452       return make_error<GenericBinaryError>(
 453           "Linking sub-section ended prematurely", object_error::parse_failed);
 454   }
 455   if (Ctx.Ptr != OrigEnd)
 456     return make_error<GenericBinaryError>("Linking section ended prematurely",
 457                                           object_error::parse_failed);
 458   return Error::success();
 459 }
 460
 461 Error WasmObjectFile::parseLinkingSectionSymtab(ReadContext &Ctx) {
 462   uint32_t Count = readVaruint32(Ctx);
 463   LinkingData.SymbolTable.reserve(Count);
 464   Symbols.reserve(Count);
 465   StringSet<> SymbolNames;
 466
 467   std::vector<wasm::WasmImport *> ImportedGlobals;
 468   std::vector<wasm::WasmImport *> ImportedFunctions;
 469   std::vector<wasm::WasmImport *> ImportedEvents;
 470   ImportedGlobals.reserve(Imports.size());
 471   ImportedFunctions.reserve(Imports.size());
 472   ImportedEvents.reserve(Imports.size());
 473   for (auto &I : Imports) {
 474     if (I.Kind == wasm::WASM_EXTERNAL_FUNCTION)
 475       ImportedFunctions.emplace_back(&I);
 476     else if (I.Kind == wasm::WASM_EXTERNAL_GLOBAL)
 477       ImportedGlobals.emplace_back(&I);
 478     else if (I.Kind == wasm::WASM_EXTERNAL_EVENT)
 479       ImportedEvents.emplace_back(&I);
 480   }
 481
 482   while (Count--) {
 483     wasm::WasmSymbolInfo Info;
 484     const wasm::WasmSignature *Signature = nullptr;
 485     const wasm::WasmGlobalType *GlobalType = nullptr;
 486     const wasm::WasmEventType *EventType = nullptr;
 487
 488     Info.Kind = readUint8(Ctx);
 489     Info.Flags = readVaruint32(Ctx);
 490     bool IsDefined = (Info.Flags & wasm::WASM_SYMBOL_UNDEFINED) == 0;
 491
 492     switch (Info.Kind) {
 493     case wasm::WASM_SYMBOL_TYPE_FUNCTION:
 494       Info.ElementIndex = readVaruint32(Ctx);
 495       if (!isValidFunctionIndex(Info.ElementIndex) ||
 496           IsDefined != isDefinedFunctionIndex(Info.ElementIndex))
 497         return make_error<GenericBinaryError>("invalid function symbol index",
 498                                               object_error::parse_failed);
 499       if (IsDefined) {
 500         Info.Name = readString(Ctx);
 501         unsigned FuncIndex = Info.ElementIndex - NumImportedFunctions;
 502         Signature = &Signatures[FunctionTypes[FuncIndex]];
 503         wasm::WasmFunction &Function = Functions[FuncIndex];
 504         if (Function.SymbolName.empty())
 505           Function.SymbolName = Info.Name;
 506       } else {
 507         wasm::WasmImport &Import = *ImportedFunctions[Info.ElementIndex];
 508         Signature = &Signatures[Import.SigIndex];
 509         Info.Name = Import.Field;
 510         Info.Module = Import.Module;
 511       }
 512       break;
 513
 514     case wasm::WASM_SYMBOL_TYPE_GLOBAL:
 515       Info.ElementIndex = readVaruint32(Ctx);
 516       if (!isValidGlobalIndex(Info.ElementIndex) ||
 517           IsDefined != isDefinedGlobalIndex(Info.ElementIndex))
 518         return make_error<GenericBinaryError>("invalid global symbol index",
 519                                               object_error::parse_failed);
 520       if (!IsDefined && (Info.Flags & wasm::WASM_SYMBOL_BINDING_MASK) ==
 521                             wasm::WASM_SYMBOL_BINDING_WEAK)
 522         return make_error<GenericBinaryError>("undefined weak global symbol",
 523                                               object_error::parse_failed);
 524       if (IsDefined) {
 525         Info.Name = readString(Ctx);
 526         unsigned GlobalIndex = Info.ElementIndex - NumImportedGlobals;
 527         wasm::WasmGlobal &Global = Globals[GlobalIndex];
 528         GlobalType = &Global.Type;
 529         if (Global.SymbolName.empty())
 530           Global.SymbolName = Info.Name;
 531       } else {
 532         wasm::WasmImport &Import = *ImportedGlobals[Info.ElementIndex];
 533         Info.Name = Import.Field;
 534         GlobalType = &Import.Global;
 535       }
 536       break;
 537
 538     case wasm::WASM_SYMBOL_TYPE_DATA:
 539       Info.Name = readString(Ctx);
 540       if (IsDefined) {
 541         uint32_t Index = readVaruint32(Ctx);
 542         if (Index >= DataSegments.size())
 543           return make_error<GenericBinaryError>("invalid data symbol index",
 544                                                 object_error::parse_failed);
 545         uint32_t Offset = readVaruint32(Ctx);
 546         uint32_t Size = readVaruint32(Ctx);
 547         if (Offset + Size > DataSegments[Index].Data.Content.size())
 548           return make_error<GenericBinaryError>("invalid data symbol offset",
 549                                                 object_error::parse_failed);
 550         Info.DataRef = wasm::WasmDataReference{Index, Offset, Size};
 551       }
 552       break;
 553
 554     case wasm::WASM_SYMBOL_TYPE_SECTION: {
 555       if ((Info.Flags & wasm::WASM_SYMBOL_BINDING_MASK) !=
 556           wasm::WASM_SYMBOL_BINDING_LOCAL)
 557         return make_error<GenericBinaryError>(
 558             "Section symbols must have local binding",
 559             object_error::parse_failed);
 560       Info.ElementIndex = readVaruint32(Ctx);
 561       // Use somewhat unique section name as symbol name.
 562       StringRef SectionName = Sections[Info.ElementIndex].Name;
 563       Info.Name = SectionName;
 564       break;
 565     }
 566
 567     case wasm::WASM_SYMBOL_TYPE_EVENT: {
 568       Info.ElementIndex = readVaruint32(Ctx);
 569       if (!isValidEventIndex(Info.ElementIndex) ||
 570           IsDefined != isDefinedEventIndex(Info.ElementIndex))
 571         return make_error<GenericBinaryError>("invalid event symbol index",
 572                                               object_error::parse_failed);
 573       if (!IsDefined && (Info.Flags & wasm::WASM_SYMBOL_BINDING_MASK) ==
 574                             wasm::WASM_SYMBOL_BINDING_WEAK)
 575         return make_error<GenericBinaryError>("undefined weak global symbol",
 576                                               object_error::parse_failed);
 577       if (IsDefined) {
 578         Info.Name = readString(Ctx);
 579         unsigned EventIndex = Info.ElementIndex - NumImportedEvents;
 580         wasm::WasmEvent &Event = Events[EventIndex];
 581         Signature = &Signatures[Event.Type.SigIndex];
 582         EventType = &Event.Type;
 583         if (Event.SymbolName.empty())
 584           Event.SymbolName = Info.Name;
 585
 586       } else {
 587         wasm::WasmImport &Import = *ImportedEvents[Info.ElementIndex];
 588         EventType = &Import.Event;
 589         Signature = &Signatures[EventType->SigIndex];
 590         Info.Name = Import.Field;
 591       }
 592       break;
 593     }
 594
 595     default:
 596       return make_error<GenericBinaryError>("Invalid symbol type",
 597                                             object_error::parse_failed);
 598     }
 599
 600     if ((Info.Flags & wasm::WASM_SYMBOL_BINDING_MASK) !=
 601             wasm::WASM_SYMBOL_BINDING_LOCAL &&
 602         !SymbolNames.insert(Info.Name).second)
 603       return make_error<GenericBinaryError>("Duplicate symbol name " +
 604                                                 Twine(Info.Name),
 605                                             object_error::parse_failed);
 606     LinkingData.SymbolTable.emplace_back(Info);
 607     Symbols.emplace_back(LinkingData.SymbolTable.back(), GlobalType, EventType,
 608                          Signature);
 609     LLVM_DEBUG(dbgs() << "Adding symbol: " << Symbols.back() << "\n");
 610   }
 611
 612   return Error::success();
 613 }
 614
 615 Error WasmObjectFile::parseLinkingSectionComdat(ReadContext &Ctx) {
 616   uint32_t ComdatCount = readVaruint32(Ctx);
 617   StringSet<> ComdatSet;
 618   for (unsigned ComdatIndex = 0; ComdatIndex < ComdatCount; ++ComdatIndex) {
 619     StringRef Name = readString(Ctx);
 620     if (Name.empty() || !ComdatSet.insert(Name).second)
 621       return make_error<GenericBinaryError>("Bad/duplicate COMDAT name " +
 622                                                 Twine(Name),
 623                                             object_error::parse_failed);
 624     LinkingData.Comdats.emplace_back(Name);
 625     uint32_t Flags = readVaruint32(Ctx);
 626     if (Flags != 0)
 627       return make_error<GenericBinaryError>("Unsupported COMDAT flags",
 628                                             object_error::parse_failed);
 629
 630     uint32_t EntryCount = readVaruint32(Ctx);
 631     while (EntryCount--) {
 632       unsigned Kind = readVaruint32(Ctx);
 633       unsigned Index = readVaruint32(Ctx);
 634       switch (Kind) {
 635       default:
 636         return make_error<GenericBinaryError>("Invalid COMDAT entry type",
 637                                               object_error::parse_failed);
 638       case wasm::WASM_COMDAT_DATA:
 639         if (Index >= DataSegments.size())
 640           return make_error<GenericBinaryError>(
 641               "COMDAT data index out of range", object_error::parse_failed);
 642         if (DataSegments[Index].Data.Comdat != UINT32_MAX)
 643           return make_error<GenericBinaryError>("Data segment in two COMDATs",
 644                                                 object_error::parse_failed);
 645         DataSegments[Index].Data.Comdat = ComdatIndex;
 646         break;
 647       case wasm::WASM_COMDAT_FUNCTION:
 648         if (!isDefinedFunctionIndex(Index))
 649           return make_error<GenericBinaryError>(
 650               "COMDAT function index out of range", object_error::parse_failed);
 651         if (getDefinedFunction(Index).Comdat != UINT32_MAX)
 652           return make_error<GenericBinaryError>("Function in two COMDATs",
 653                                                 object_error::parse_failed);
 654         getDefinedFunction(Index).Comdat = ComdatIndex;
 655         break;
 656       }
 657     }
 658   }
 659   return Error::success();
 660 }
 661
 662 Error WasmObjectFile::parseProducersSection(ReadContext &Ctx) {
 663   llvm::SmallSet<StringRef, 3> FieldsSeen;
 664   uint32_t Fields = readVaruint32(Ctx);
 665   for (size_t i = 0; i < Fields; ++i) {
 666     StringRef FieldName = readString(Ctx);
 667     if (!FieldsSeen.insert(FieldName).second)
 668       return make_error<GenericBinaryError>(
 669           "Producers section does not have unique fields",
 670           object_error::parse_failed);
 671     std::vector<std::pair<std::string, std::string>> *ProducerVec = nullptr;
 672     if (FieldName == "language") {
 673       ProducerVec = &ProducerInfo.Languages;
 674     } else if (FieldName == "processed-by") {
 675       ProducerVec = &ProducerInfo.Tools;
 676     } else if (FieldName == "sdk") {
 677       ProducerVec = &ProducerInfo.SDKs;
 678     } else {
 679       return make_error<GenericBinaryError>(
 680           "Producers section field is not named one of language, processed-by, "
 681           "or sdk",
 682           object_error::parse_failed);
 683     }
 684     uint32_t ValueCount = readVaruint32(Ctx);
 685     llvm::SmallSet<StringRef, 8> ProducersSeen;
 686     for (size_t j = 0; j < ValueCount; ++j) {
 687       StringRef Name = readString(Ctx);
 688       StringRef Version = readString(Ctx);
 689       if (!ProducersSeen.insert(Name).second) {
 690         return make_error<GenericBinaryError>(
 691             "Producers section contains repeated producer",
 692             object_error::parse_failed);
 693       }
 694       ProducerVec->emplace_back(Name, Version);
 695     }
 696   }
 697   if (Ctx.Ptr != Ctx.End)
 698     return make_error<GenericBinaryError>("Producers section ended prematurely",
 699                                           object_error::parse_failed);
 700   return Error::success();
 701 }
 702
 703 Error WasmObjectFile::parseRelocSection(StringRef Name, ReadContext &Ctx) {
 704   uint32_t SectionIndex = readVaruint32(Ctx);
 705   if (SectionIndex >= Sections.size())
 706     return make_error<GenericBinaryError>("Invalid section index",
 707                                           object_error::parse_failed);
 708   WasmSection &Section = Sections[SectionIndex];
 709   uint32_t RelocCount = readVaruint32(Ctx);
 710   uint32_t EndOffset = Section.Content.size();
 711   uint32_t PreviousOffset = 0;
 712   while (RelocCount--) {
 713     wasm::WasmRelocation Reloc = {};
 714     Reloc.Type = readVaruint32(Ctx);
 715     Reloc.Offset = readVaruint32(Ctx);
 716     if (Reloc.Offset < PreviousOffset)
 717       return make_error<GenericBinaryError>("Relocations not in offset order",
 718                                             object_error::parse_failed);
 719     PreviousOffset = Reloc.Offset;
 720     Reloc.Index = readVaruint32(Ctx);
 721     switch (Reloc.Type) {
 722     case wasm::R_WEBASSEMBLY_FUNCTION_INDEX_LEB:
 723     case wasm::R_WEBASSEMBLY_TABLE_INDEX_SLEB:
 724     case wasm::R_WEBASSEMBLY_TABLE_INDEX_I32:
 725       if (!isValidFunctionSymbol(Reloc.Index))
 726         return make_error<GenericBinaryError>("Bad relocation function index",
 727                                               object_error::parse_failed);
 728       break;
 729     case wasm::R_WEBASSEMBLY_TYPE_INDEX_LEB:
 730       if (Reloc.Index >= Signatures.size())
 731         return make_error<GenericBinaryError>("Bad relocation type index",
 732                                               object_error::parse_failed);
 733       break;
 734     case wasm::R_WEBASSEMBLY_GLOBAL_INDEX_LEB:
 735       if (!isValidGlobalSymbol(Reloc.Index))
 736         return make_error<GenericBinaryError>("Bad relocation global index",
 737                                               object_error::parse_failed);
 738       break;
 739     case wasm::R_WEBASSEMBLY_EVENT_INDEX_LEB:
 740       if (!isValidEventSymbol(Reloc.Index))
 741         return make_error<GenericBinaryError>("Bad relocation event index",
 742                                               object_error::parse_failed);
 743       break;
 744     case wasm::R_WEBASSEMBLY_MEMORY_ADDR_LEB:
 745     case wasm::R_WEBASSEMBLY_MEMORY_ADDR_SLEB:
 746     case wasm::R_WEBASSEMBLY_MEMORY_ADDR_I32:
 747       if (!isValidDataSymbol(Reloc.Index))
 748         return make_error<GenericBinaryError>("Bad relocation data index",
 749                                               object_error::parse_failed);
 750       Reloc.Addend = readVarint32(Ctx);
 751       break;
 752     case wasm::R_WEBASSEMBLY_FUNCTION_OFFSET_I32:
 753       if (!isValidFunctionSymbol(Reloc.Index))
 754         return make_error<GenericBinaryError>("Bad relocation function index",
 755                                               object_error::parse_failed);
 756       Reloc.Addend = readVarint32(Ctx);
 757       break;
 758     case wasm::R_WEBASSEMBLY_SECTION_OFFSET_I32:
 759       if (!isValidSectionSymbol(Reloc.Index))
 760         return make_error<GenericBinaryError>("Bad relocation section index",
 761                                               object_error::parse_failed);
 762       Reloc.Addend = readVarint32(Ctx);
 763       break;
 764     default:
 765       return make_error<GenericBinaryError>("Bad relocation type: " +
 766                                                 Twine(Reloc.Type),
 767                                             object_error::parse_failed);
 768     }
 769
 770     // Relocations must fit inside the section, and must appear in order.  They
 771     // also shouldn't overlap a function/element boundary, but we don't bother
 772     // to check that.
 773     uint64_t Size = 5;
 774     if (Reloc.Type == wasm::R_WEBASSEMBLY_TABLE_INDEX_I32 ||
 775         Reloc.Type == wasm::R_WEBASSEMBLY_MEMORY_ADDR_I32 ||
 776         Reloc.Type == wasm::R_WEBASSEMBLY_SECTION_OFFSET_I32 ||
 777         Reloc.Type == wasm::R_WEBASSEMBLY_FUNCTION_OFFSET_I32)
 778       Size = 4;
 779     if (Reloc.Offset + Size > EndOffset)
 780       return make_error<GenericBinaryError>("Bad relocation offset",
 781                                             object_error::parse_failed);
 782
 783     Section.Relocations.push_back(Reloc);
 784   }
 785   if (Ctx.Ptr != Ctx.End)
 786     return make_error<GenericBinaryError>("Reloc section ended prematurely",
 787                                           object_error::parse_failed);
 788   return Error::success();
 789 }
 790
 791 Error WasmObjectFile::parseCustomSection(WasmSection &Sec, ReadContext &Ctx) {
 792   if (Sec.Name == "dylink") {
 793     if (Error Err = parseDylinkSection(Ctx))
 794       return Err;
 795   } else if (Sec.Name == "name") {
 796     if (Error Err = parseNameSection(Ctx))
 797       return Err;
 798   } else if (Sec.Name == "linking") {
 799     if (Error Err = parseLinkingSection(Ctx))
 800       return Err;
 801   } else if (Sec.Name == "producers") {
 802     if (Error Err = parseProducersSection(Ctx))
 803       return Err;
 804   } else if (Sec.Name.startswith("reloc.")) {
 805     if (Error Err = parseRelocSection(Sec.Name, Ctx))
 806       return Err;
 807   }
 808   return Error::success();
 809 }
 810
 811 Error WasmObjectFile::parseTypeSection(ReadContext &Ctx) {
 812   uint32_t Count = readVaruint32(Ctx);
 813   Signatures.reserve(Count);
 814   while (Count--) {
 815     wasm::WasmSignature Sig;
 816     uint8_t Form = readUint8(Ctx);
 817     if (Form != wasm::WASM_TYPE_FUNC) {
 818       return make_error<GenericBinaryError>("Invalid signature type",
 819                                             object_error::parse_failed);
 820     }
 821     uint32_t ParamCount = readVaruint32(Ctx);
 822     Sig.Params.reserve(ParamCount);
 823     while (ParamCount--) {
 824       uint32_t ParamType = readUint8(Ctx);
 825       Sig.Params.push_back(wasm::ValType(ParamType));
 826     }
 827     uint32_t ReturnCount = readVaruint32(Ctx);
 828     if (ReturnCount) {
 829       if (ReturnCount != 1) {
 830         return make_error<GenericBinaryError>(
 831             "Multiple return types not supported", object_error::parse_failed);
 832       }
 833       Sig.Returns.push_back(wasm::ValType(readUint8(Ctx)));
 834     }
 835     Signatures.push_back(std::move(Sig));
 836   }
 837   if (Ctx.Ptr != Ctx.End)
 838     return make_error<GenericBinaryError>("Type section ended prematurely",
 839                                           object_error::parse_failed);
 840   return Error::success();
 841 }
 842
 843 Error WasmObjectFile::parseImportSection(ReadContext &Ctx) {
 844   uint32_t Count = readVaruint32(Ctx);
 845   Imports.reserve(Count);
 846   for (uint32_t i = 0; i < Count; i++) {
 847     wasm::WasmImport Im;
 848     Im.Module = readString(Ctx);
 849     Im.Field = readString(Ctx);
 850     Im.Kind = readUint8(Ctx);
 851     switch (Im.Kind) {
 852     case wasm::WASM_EXTERNAL_FUNCTION:
 853       NumImportedFunctions++;
 854       Im.SigIndex = readVaruint32(Ctx);
 855       break;
 856     case wasm::WASM_EXTERNAL_GLOBAL:
 857       NumImportedGlobals++;
 858       Im.Global.Type = readUint8(Ctx);
 859       Im.Global.Mutable = readVaruint1(Ctx);
 860       break;
 861     case wasm::WASM_EXTERNAL_MEMORY:
 862       Im.Memory = readLimits(Ctx);
 863       break;
 864     case wasm::WASM_EXTERNAL_TABLE:
 865       Im.Table = readTable(Ctx);
 866       if (Im.Table.ElemType != wasm::WASM_TYPE_FUNCREF)
 867         return make_error<GenericBinaryError>("Invalid table element type",
 868                                               object_error::parse_failed);
 869       break;
 870     case wasm::WASM_EXTERNAL_EVENT:
 871       NumImportedEvents++;
 872       Im.Event.Attribute = readVarint32(Ctx);
 873       Im.Event.SigIndex = readVarint32(Ctx);
 874       break;
 875     default:
 876       return make_error<GenericBinaryError>("Unexpected import kind",
 877                                             object_error::parse_failed);
 878     }
 879     Imports.push_back(Im);
 880   }
 881   if (Ctx.Ptr != Ctx.End)
 882     return make_error<GenericBinaryError>("Import section ended prematurely",
 883                                           object_error::parse_failed);
 884   return Error::success();
 885 }
 886
 887 Error WasmObjectFile::parseFunctionSection(ReadContext &Ctx) {
 888   uint32_t Count = readVaruint32(Ctx);
 889   FunctionTypes.reserve(Count);
 890   uint32_t NumTypes = Signatures.size();
 891   while (Count--) {
 892     uint32_t Type = readVaruint32(Ctx);
 893     if (Type >= NumTypes)
 894       return make_error<GenericBinaryError>("Invalid function type",
 895                                             object_error::parse_failed);
 896     FunctionTypes.push_back(Type);
 897   }
 898   if (Ctx.Ptr != Ctx.End)
 899     return make_error<GenericBinaryError>("Function section ended prematurely",
 900                                           object_error::parse_failed);
 901   return Error::success();
 902 }
 903
 904 Error WasmObjectFile::parseTableSection(ReadContext &Ctx) {
 905   uint32_t Count = readVaruint32(Ctx);
 906   Tables.reserve(Count);
 907   while (Count--) {
 908     Tables.push_back(readTable(Ctx));
 909     if (Tables.back().ElemType != wasm::WASM_TYPE_FUNCREF) {
 910       return make_error<GenericBinaryError>("Invalid table element type",
 911                                             object_error::parse_failed);
 912     }
 913   }
 914   if (Ctx.Ptr != Ctx.End)
 915     return make_error<GenericBinaryError>("Table section ended prematurely",
 916                                           object_error::parse_failed);
 917   return Error::success();
 918 }
 919
 920 Error WasmObjectFile::parseMemorySection(ReadContext &Ctx) {
 921   uint32_t Count = readVaruint32(Ctx);
 922   Memories.reserve(Count);
 923   while (Count--) {
 924     Memories.push_back(readLimits(Ctx));
 925   }
 926   if (Ctx.Ptr != Ctx.End)
 927     return make_error<GenericBinaryError>("Memory section ended prematurely",
 928                                           object_error::parse_failed);
 929   return Error::success();
 930 }
 931
 932 Error WasmObjectFile::parseGlobalSection(ReadContext &Ctx) {
 933   GlobalSection = Sections.size();
 934   uint32_t Count = readVaruint32(Ctx);
 935   Globals.reserve(Count);
 936   while (Count--) {
 937     wasm::WasmGlobal Global;
 938     Global.Index = NumImportedGlobals + Globals.size();
 939     Global.Type.Type = readUint8(Ctx);
 940     Global.Type.Mutable = readVaruint1(Ctx);
 941     if (Error Err = readInitExpr(Global.InitExpr, Ctx))
 942       return Err;
 943     Globals.push_back(Global);
 944   }
 945   if (Ctx.Ptr != Ctx.End)
 946     return make_error<GenericBinaryError>("Global section ended prematurely",
 947                                           object_error::parse_failed);
 948   return Error::success();
 949 }
 950
 951 Error WasmObjectFile::parseEventSection(ReadContext &Ctx) {
 952   EventSection = Sections.size();
 953   uint32_t Count = readVarint32(Ctx);
 954   Events.reserve(Count);
 955   while (Count--) {
 956     wasm::WasmEvent Event;
 957     Event.Index = NumImportedEvents + Events.size();
 958     Event.Type.Attribute = readVaruint32(Ctx);
 959     Event.Type.SigIndex = readVarint32(Ctx);
 960     Events.push_back(Event);
 961   }
 962
 963   if (Ctx.Ptr != Ctx.End)
 964     return make_error<GenericBinaryError>("Event section ended prematurely",
 965                                           object_error::parse_failed);
 966   return Error::success();
 967 }
 968
 969 Error WasmObjectFile::parseExportSection(ReadContext &Ctx) {
 970   uint32_t Count = readVaruint32(Ctx);
 971   Exports.reserve(Count);
 972   for (uint32_t i = 0; i < Count; i++) {
 973     wasm::WasmExport Ex;
 974     Ex.Name = readString(Ctx);
 975     Ex.Kind = readUint8(Ctx);
 976     Ex.Index = readVaruint32(Ctx);
 977     switch (Ex.Kind) {
 978     case wasm::WASM_EXTERNAL_FUNCTION:
 979       if (!isValidFunctionIndex(Ex.Index))
 980         return make_error<GenericBinaryError>("Invalid function export",
 981                                               object_error::parse_failed);
 982       break;
 983     case wasm::WASM_EXTERNAL_GLOBAL:
 984       if (!isValidGlobalIndex(Ex.Index))
 985         return make_error<GenericBinaryError>("Invalid global export",
 986                                               object_error::parse_failed);
 987       break;
 988     case wasm::WASM_EXTERNAL_EVENT:
 989       if (!isValidEventIndex(Ex.Index))
 990         return make_error<GenericBinaryError>("Invalid event export",
 991                                               object_error::parse_failed);
 992       break;
 993     case wasm::WASM_EXTERNAL_MEMORY:
 994     case wasm::WASM_EXTERNAL_TABLE:
 995       break;
 996     default:
 997       return make_error<GenericBinaryError>("Unexpected export kind",
 998                                             object_error::parse_failed);
 999     }
1000     Exports.push_back(Ex);
1001   }
1002   if (Ctx.Ptr != Ctx.End)
1003     return make_error<GenericBinaryError>("Export section ended prematurely",
1004                                           object_error::parse_failed);
1005   return Error::success();
1006 }
1007
1008 bool WasmObjectFile::isValidFunctionIndex(uint32_t Index) const {
1009   return Index < NumImportedFunctions + FunctionTypes.size();
1010 }
1011
1012 bool WasmObjectFile::isDefinedFunctionIndex(uint32_t Index) const {
1013   return Index >= NumImportedFunctions && isValidFunctionIndex(Index);
1014 }
1015
1016 bool WasmObjectFile::isValidGlobalIndex(uint32_t Index) const {
1017   return Index < NumImportedGlobals + Globals.size();
1018 }
1019
1020 bool WasmObjectFile::isDefinedGlobalIndex(uint32_t Index) const {
1021   return Index >= NumImportedGlobals && isValidGlobalIndex(Index);
1022 }
1023
1024 bool WasmObjectFile::isValidEventIndex(uint32_t Index) const {
1025   return Index < NumImportedEvents + Events.size();
1026 }
1027
1028 bool WasmObjectFile::isDefinedEventIndex(uint32_t Index) const {
1029   return Index >= NumImportedEvents && isValidEventIndex(Index);
1030 }
1031
1032 bool WasmObjectFile::isValidFunctionSymbol(uint32_t Index) const {
1033   return Index < Symbols.size() && Symbols[Index].isTypeFunction();
1034 }
1035
1036 bool WasmObjectFile::isValidGlobalSymbol(uint32_t Index) const {
1037   return Index < Symbols.size() && Symbols[Index].isTypeGlobal();
1038 }
1039
1040 bool WasmObjectFile::isValidEventSymbol(uint32_t Index) const {
1041   return Index < Symbols.size() && Symbols[Index].isTypeEvent();
1042 }
1043
1044 bool WasmObjectFile::isValidDataSymbol(uint32_t Index) const {
1045   return Index < Symbols.size() && Symbols[Index].isTypeData();
1046 }
1047
1048 bool WasmObjectFile::isValidSectionSymbol(uint32_t Index) const {
1049   return Index < Symbols.size() && Symbols[Index].isTypeSection();
1050 }
1051
1052 wasm::WasmFunction &WasmObjectFile::getDefinedFunction(uint32_t Index) {
1053   assert(isDefinedFunctionIndex(Index));
1054   return Functions[Index - NumImportedFunctions];
1055 }
1056
1057 const wasm::WasmFunction &
1058 WasmObjectFile::getDefinedFunction(uint32_t Index) const {
1059   assert(isDefinedFunctionIndex(Index));
1060   return Functions[Index - NumImportedFunctions];
1061 }
1062
1063 wasm::WasmGlobal &WasmObjectFile::getDefinedGlobal(uint32_t Index) {
1064   assert(isDefinedGlobalIndex(Index));
1065   return Globals[Index - NumImportedGlobals];
1066 }
1067
1068 wasm::WasmEvent &WasmObjectFile::getDefinedEvent(uint32_t Index) {
1069   assert(isDefinedEventIndex(Index));
1070   return Events[Index - NumImportedEvents];
1071 }
1072
1073 Error WasmObjectFile::parseStartSection(ReadContext &Ctx) {
1074   StartFunction = readVaruint32(Ctx);
1075   if (!isValidFunctionIndex(StartFunction))
1076     return make_error<GenericBinaryError>("Invalid start function",
1077                                           object_error::parse_failed);
1078   return Error::success();
1079 }
1080
1081 Error WasmObjectFile::parseCodeSection(ReadContext &Ctx) {
1082   CodeSection = Sections.size();
1083   uint32_t FunctionCount = readVaruint32(Ctx);
1084   if (FunctionCount != FunctionTypes.size()) {
1085     return make_error<GenericBinaryError>("Invalid function count",
1086                                           object_error::parse_failed);
1087   }
1088
1089   while (FunctionCount--) {
1090     wasm::WasmFunction Function;
1091     const uint8_t *FunctionStart = Ctx.Ptr;
1092     uint32_t Size = readVaruint32(Ctx);
1093     const uint8_t *FunctionEnd = Ctx.Ptr + Size;
1094
1095     Function.CodeOffset = Ctx.Ptr - FunctionStart;
1096     Function.Index = NumImportedFunctions + Functions.size();
1097     Function.CodeSectionOffset = FunctionStart - Ctx.Start;
1098     Function.Size = FunctionEnd - FunctionStart;
1099
1100     uint32_t NumLocalDecls = readVaruint32(Ctx);
1101     Function.Locals.reserve(NumLocalDecls);
1102     while (NumLocalDecls--) {
1103       wasm::WasmLocalDecl Decl;
1104       Decl.Count = readVaruint32(Ctx);
1105       Decl.Type = readUint8(Ctx);
1106       Function.Locals.push_back(Decl);
1107     }
1108
1109     uint32_t BodySize = FunctionEnd - Ctx.Ptr;
1110     Function.Body = ArrayRef<uint8_t>(Ctx.Ptr, BodySize);
1111     // This will be set later when reading in the linking metadata section.
1112     Function.Comdat = UINT32_MAX;
1113     Ctx.Ptr += BodySize;
1114     assert(Ctx.Ptr == FunctionEnd);
1115     Functions.push_back(Function);
1116   }
1117   if (Ctx.Ptr != Ctx.End)
1118     return make_error<GenericBinaryError>("Code section ended prematurely",
1119                                           object_error::parse_failed);
1120   return Error::success();
1121 }
1122
1123 Error WasmObjectFile::parseElemSection(ReadContext &Ctx) {
1124   uint32_t Count = readVaruint32(Ctx);
1125   ElemSegments.reserve(Count);
1126   while (Count--) {
1127     wasm::WasmElemSegment Segment;
1128     Segment.TableIndex = readVaruint32(Ctx);
1129     if (Segment.TableIndex != 0) {
1130       return make_error<GenericBinaryError>("Invalid TableIndex",
1131                                             object_error::parse_failed);
1132     }
1133     if (Error Err = readInitExpr(Segment.Offset, Ctx))
1134       return Err;
1135     uint32_t NumElems = readVaruint32(Ctx);
1136     while (NumElems--) {
1137       Segment.Functions.push_back(readVaruint32(Ctx));
1138     }
1139     ElemSegments.push_back(Segment);
1140   }
1141   if (Ctx.Ptr != Ctx.End)
1142     return make_error<GenericBinaryError>("Elem section ended prematurely",
1143                                           object_error::parse_failed);
1144   return Error::success();
1145 }
1146
1147 Error WasmObjectFile::parseDataSection(ReadContext &Ctx) {
1148   DataSection = Sections.size();
1149   uint32_t Count = readVaruint32(Ctx);
1150   DataSegments.reserve(Count);
1151   while (Count--) {
1152     WasmSegment Segment;
1153     Segment.Data.MemoryIndex = readVaruint32(Ctx);
1154     if (Error Err = readInitExpr(Segment.Data.Offset, Ctx))
1155       return Err;
1156     uint32_t Size = readVaruint32(Ctx);
1157     if (Size > (size_t)(Ctx.End - Ctx.Ptr))
1158       return make_error<GenericBinaryError>("Invalid segment size",
1159                                             object_error::parse_failed);
1160     Segment.Data.Content = ArrayRef<uint8_t>(Ctx.Ptr, Size);
1161     // The rest of these Data fields are set later, when reading in the linking
1162     // metadata section.
1163     Segment.Data.Alignment = 0;
1164     Segment.Data.Flags = 0;
1165     Segment.Data.Comdat = UINT32_MAX;
1166     Segment.SectionOffset = Ctx.Ptr - Ctx.Start;
1167     Ctx.Ptr += Size;
1168     DataSegments.push_back(Segment);
1169   }
1170   if (Ctx.Ptr != Ctx.End)
1171     return make_error<GenericBinaryError>("Data section ended prematurely",
1172                                           object_error::parse_failed);
1173   return Error::success();
1174 }
1175
1176 const uint8_t *WasmObjectFile::getPtr(size_t Offset) const {
1177   return reinterpret_cast<const uint8_t *>(getData().data() + Offset);
1178 }
1179
1180 const wasm::WasmObjectHeader &WasmObjectFile::getHeader() const {
1181   return Header;
1182 }
1183
1184 void WasmObjectFile::moveSymbolNext(DataRefImpl &Symb) const { Symb.d.b++; }
1185
1186 uint32_t WasmObjectFile::getSymbolFlags(DataRefImpl Symb) const {
1187   uint32_t Result = SymbolRef::SF_None;
1188   const WasmSymbol &Sym = getWasmSymbol(Symb);
1189
1190   LLVM_DEBUG(dbgs() << "getSymbolFlags: ptr=" << &Sym << " " << Sym << "\n");
1191   if (Sym.isBindingWeak())
1192     Result |= SymbolRef::SF_Weak;
1193   if (!Sym.isBindingLocal())
1194     Result |= SymbolRef::SF_Global;
1195   if (Sym.isHidden())
1196     Result |= SymbolRef::SF_Hidden;
1197   if (!Sym.isDefined())
1198     Result |= SymbolRef::SF_Undefined;
1199   if (Sym.isTypeFunction())
1200     Result |= SymbolRef::SF_Executable;
1201   return Result;
1202 }
1203
1204 basic_symbol_iterator WasmObjectFile::symbol_begin() const {
1205   DataRefImpl Ref;
1206   Ref.d.a = 1; // Arbitrary non-zero value so that Ref.p is non-null
1207   Ref.d.b = 0; // Symbol index
1208   return BasicSymbolRef(Ref, this);
1209 }
1210
1211 basic_symbol_iterator WasmObjectFile::symbol_end() const {
1212   DataRefImpl Ref;
1213   Ref.d.a = 1; // Arbitrary non-zero value so that Ref.p is non-null
1214   Ref.d.b = Symbols.size(); // Symbol index
1215   return BasicSymbolRef(Ref, this);
1216 }
1217
1218 const WasmSymbol &WasmObjectFile::getWasmSymbol(const DataRefImpl &Symb) const {
1219   return Symbols[Symb.d.b];
1220 }
1221
1222 const WasmSymbol &WasmObjectFile::getWasmSymbol(const SymbolRef &Symb) const {
1223   return getWasmSymbol(Symb.getRawDataRefImpl());
1224 }
1225
1226 Expected<StringRef> WasmObjectFile::getSymbolName(DataRefImpl Symb) const {
1227   return getWasmSymbol(Symb).Info.Name;
1228 }
1229
1230 Expected<uint64_t> WasmObjectFile::getSymbolAddress(DataRefImpl Symb) const {
1231   auto &Sym = getWasmSymbol(Symb);
1232   if (Sym.Info.Kind == wasm::WASM_SYMBOL_TYPE_FUNCTION &&
1233       isDefinedFunctionIndex(Sym.Info.ElementIndex))
1234     return getDefinedFunction(Sym.Info.ElementIndex).CodeSectionOffset;
1235   else
1236     return getSymbolValue(Symb);
1237 }
1238
1239 uint64_t WasmObjectFile::getWasmSymbolValue(const WasmSymbol &Sym) const {
1240   switch (Sym.Info.Kind) {
1241   case wasm::WASM_SYMBOL_TYPE_FUNCTION:
1242   case wasm::WASM_SYMBOL_TYPE_GLOBAL:
1243   case wasm::WASM_SYMBOL_TYPE_EVENT:
1244     return Sym.Info.ElementIndex;
1245   case wasm::WASM_SYMBOL_TYPE_DATA: {
1246     // The value of a data symbol is the segment offset, plus the symbol
1247     // offset within the segment.
1248     uint32_t SegmentIndex = Sym.Info.DataRef.Segment;
1249     const wasm::WasmDataSegment &Segment = DataSegments[SegmentIndex].Data;
1250     assert(Segment.Offset.Opcode == wasm::WASM_OPCODE_I32_CONST);
1251     return Segment.Offset.Value.Int32 + Sym.Info.DataRef.Offset;
1252   }
1253   case wasm::WASM_SYMBOL_TYPE_SECTION:
1254     return 0;
1255   }
1256   llvm_unreachable("invalid symbol type");
1257 }
1258
1259 uint64_t WasmObjectFile::getSymbolValueImpl(DataRefImpl Symb) const {
1260   return getWasmSymbolValue(getWasmSymbol(Symb));
1261 }
1262
1263 uint32_t WasmObjectFile::getSymbolAlignment(DataRefImpl Symb) const {
1264   llvm_unreachable("not yet implemented");
1265   return 0;
1266 }
1267
1268 uint64_t WasmObjectFile::getCommonSymbolSizeImpl(DataRefImpl Symb) const {
1269   llvm_unreachable("not yet implemented");
1270   return 0;
1271 }
1272
1273 Expected<SymbolRef::Type>
1274 WasmObjectFile::getSymbolType(DataRefImpl Symb) const {
1275   const WasmSymbol &Sym = getWasmSymbol(Symb);
1276
1277   switch (Sym.Info.Kind) {
1278   case wasm::WASM_SYMBOL_TYPE_FUNCTION:
1279     return SymbolRef::ST_Function;
1280   case wasm::WASM_SYMBOL_TYPE_GLOBAL:
1281     return SymbolRef::ST_Other;
1282   case wasm::WASM_SYMBOL_TYPE_DATA:
1283     return SymbolRef::ST_Data;
1284   case wasm::WASM_SYMBOL_TYPE_SECTION:
1285     return SymbolRef::ST_Debug;
1286   case wasm::WASM_SYMBOL_TYPE_EVENT:
1287     return SymbolRef::ST_Other;
1288   }
1289
1290   llvm_unreachable("Unknown WasmSymbol::SymbolType");
1291   return SymbolRef::ST_Other;
1292 }
1293
1294 Expected<section_iterator>
1295 WasmObjectFile::getSymbolSection(DataRefImpl Symb) const {
1296   const WasmSymbol &Sym = getWasmSymbol(Symb);
1297   if (Sym.isUndefined())
1298     return section_end();
1299
1300   DataRefImpl Ref;
1301   switch (Sym.Info.Kind) {
1302   case wasm::WASM_SYMBOL_TYPE_FUNCTION:
1303     Ref.d.a = CodeSection;
1304     break;
1305   case wasm::WASM_SYMBOL_TYPE_GLOBAL:
1306     Ref.d.a = GlobalSection;
1307     break;
1308   case wasm::WASM_SYMBOL_TYPE_DATA:
1309     Ref.d.a = DataSection;
1310     break;
1311   case wasm::WASM_SYMBOL_TYPE_SECTION:
1312     Ref.d.a = Sym.Info.ElementIndex;
1313     break;
1314   case wasm::WASM_SYMBOL_TYPE_EVENT:
1315     Ref.d.a = EventSection;
1316     break;
1317   default:
1318     llvm_unreachable("Unknown WasmSymbol::SymbolType");
1319   }
1320   return section_iterator(SectionRef(Ref, this));
1321 }
1322
1323 void WasmObjectFile::moveSectionNext(DataRefImpl &Sec) const { Sec.d.a++; }
1324
1325 std::error_code WasmObjectFile::getSectionName(DataRefImpl Sec,
1326                                                StringRef &Res) const {
1327   const WasmSection &S = Sections[Sec.d.a];
1328 #define ECase(X)                                                               \
1329   case wasm::WASM_SEC_##X:                                                     \
1330     Res = #X;                                                                  \
1331     break
1332   switch (S.Type) {
1333     ECase(TYPE);
1334     ECase(IMPORT);
1335     ECase(FUNCTION);
1336     ECase(TABLE);
1337     ECase(MEMORY);
1338     ECase(GLOBAL);
1339     ECase(EVENT);
1340     ECase(EXPORT);
1341     ECase(START);
1342     ECase(ELEM);
1343     ECase(CODE);
1344     ECase(DATA);
1345   case wasm::WASM_SEC_CUSTOM:
1346     Res = S.Name;
1347     break;
1348   default:
1349     return object_error::invalid_section_index;
1350   }
1351 #undef ECase
1352   return std::error_code();
1353 }
1354
1355 uint64_t WasmObjectFile::getSectionAddress(DataRefImpl Sec) const { return 0; }
1356
1357 uint64_t WasmObjectFile::getSectionIndex(DataRefImpl Sec) const {
1358   return Sec.d.a;
1359 }
1360
1361 uint64_t WasmObjectFile::getSectionSize(DataRefImpl Sec) const {
1362   const WasmSection &S = Sections[Sec.d.a];
1363   return S.Content.size();
1364 }
1365
1366 std::error_code WasmObjectFile::getSectionContents(DataRefImpl Sec,
1367                                                    StringRef &Res) const {
1368   const WasmSection &S = Sections[Sec.d.a];
1369   // This will never fail since wasm sections can never be empty (user-sections
1370   // must have a name and non-user sections each have a defined structure).
1371   Res = StringRef(reinterpret_cast<const char *>(S.Content.data()),
1372                   S.Content.size());
1373   return std::error_code();
1374 }
1375
1376 uint64_t WasmObjectFile::getSectionAlignment(DataRefImpl Sec) const {
1377   return 1;
1378 }
1379
1380 bool WasmObjectFile::isSectionCompressed(DataRefImpl Sec) const {
1381   return false;
1382 }
1383
1384 bool WasmObjectFile::isSectionText(DataRefImpl Sec) const {
1385   return getWasmSection(Sec).Type == wasm::WASM_SEC_CODE;
1386 }
1387
1388 bool WasmObjectFile::isSectionData(DataRefImpl Sec) const {
1389   return getWasmSection(Sec).Type == wasm::WASM_SEC_DATA;
1390 }
1391
1392 bool WasmObjectFile::isSectionBSS(DataRefImpl Sec) const { return false; }
1393
1394 bool WasmObjectFile::isSectionVirtual(DataRefImpl Sec) const { return false; }
1395
1396 bool WasmObjectFile::isSectionBitcode(DataRefImpl Sec) const { return false; }
1397
1398 relocation_iterator WasmObjectFile::section_rel_begin(DataRefImpl Ref) const {
1399   DataRefImpl RelocRef;
1400   RelocRef.d.a = Ref.d.a;
1401   RelocRef.d.b = 0;
1402   return relocation_iterator(RelocationRef(RelocRef, this));
1403 }
1404
1405 relocation_iterator WasmObjectFile::section_rel_end(DataRefImpl Ref) const {
1406   const WasmSection &Sec = getWasmSection(Ref);
1407   DataRefImpl RelocRef;
1408   RelocRef.d.a = Ref.d.a;
1409   RelocRef.d.b = Sec.Relocations.size();
1410   return relocation_iterator(RelocationRef(RelocRef, this));
1411 }
1412
1413 void WasmObjectFile::moveRelocationNext(DataRefImpl &Rel) const { Rel.d.b++; }
1414
1415 uint64_t WasmObjectFile::getRelocationOffset(DataRefImpl Ref) const {
1416   const wasm::WasmRelocation &Rel = getWasmRelocation(Ref);
1417   return Rel.Offset;
1418 }
1419
1420 symbol_iterator WasmObjectFile::getRelocationSymbol(DataRefImpl Ref) const {
1421   const wasm::WasmRelocation &Rel = getWasmRelocation(Ref);
1422   if (Rel.Type == wasm::R_WEBASSEMBLY_TYPE_INDEX_LEB)
1423     return symbol_end();
1424   DataRefImpl Sym;
1425   Sym.d.a = Rel.Index;
1426   Sym.d.b = 0;
1427   return symbol_iterator(SymbolRef(Sym, this));
1428 }
1429
1430 uint64_t WasmObjectFile::getRelocationType(DataRefImpl Ref) const {
1431   const wasm::WasmRelocation &Rel = getWasmRelocation(Ref);
1432   return Rel.Type;
1433 }
1434
1435 void WasmObjectFile::getRelocationTypeName(
1436     DataRefImpl Ref, SmallVectorImpl<char> &Result) const {
1437   const wasm::WasmRelocation &Rel = getWasmRelocation(Ref);
1438   StringRef Res = "Unknown";
1439
1440 #define WASM_RELOC(name, value)                                                \
1441   case wasm::name:                                                             \
1442     Res = #name;                                                               \
1443     break;
1444
1445   switch (Rel.Type) {
1446 #include "llvm/BinaryFormat/WasmRelocs.def"
1447   }
1448
1449 #undef WASM_RELOC
1450
1451   Result.append(Res.begin(), Res.end());
1452 }
1453
1454 section_iterator WasmObjectFile::section_begin() const {
1455   DataRefImpl Ref;
1456   Ref.d.a = 0;
1457   return section_iterator(SectionRef(Ref, this));
1458 }
1459
1460 section_iterator WasmObjectFile::section_end() const {
1461   DataRefImpl Ref;
1462   Ref.d.a = Sections.size();
1463   return section_iterator(SectionRef(Ref, this));
1464 }
1465
1466 uint8_t WasmObjectFile::getBytesInAddress() const { return 4; }
1467
1468 StringRef WasmObjectFile::getFileFormatName() const { return "WASM"; }
1469
1470 Triple::ArchType WasmObjectFile::getArch() const { return Triple::wasm32; }
1471
1472 SubtargetFeatures WasmObjectFile::getFeatures() const {
1473   return SubtargetFeatures();
1474 }
1475
1476 bool WasmObjectFile::isRelocatableObject() const { return HasLinkingSection; }
1477
1478 bool WasmObjectFile::isSharedObject() const { return HasDylinkSection; }
1479
1480 const WasmSection &WasmObjectFile::getWasmSection(DataRefImpl Ref) const {
1481   assert(Ref.d.a < Sections.size());
1482   return Sections[Ref.d.a];
1483 }
1484
1485 const WasmSection &
1486 WasmObjectFile::getWasmSection(const SectionRef &Section) const {
1487   return getWasmSection(Section.getRawDataRefImpl());
1488 }
1489
1490 const wasm::WasmRelocation &
1491 WasmObjectFile::getWasmRelocation(const RelocationRef &Ref) const {
1492   return getWasmRelocation(Ref.getRawDataRefImpl());
1493 }
1494
1495 const wasm::WasmRelocation &
1496 WasmObjectFile::getWasmRelocation(DataRefImpl Ref) const {
1497   assert(Ref.d.a < Sections.size());
1498   const WasmSection &Sec = Sections[Ref.d.a];
1499   assert(Ref.d.b < Sec.Relocations.size());
1500   return Sec.Relocations[Ref.d.b];
1501 }
1502
1503 int WasmSectionOrderChecker::getSectionOrder(unsigned ID,
1504                                              StringRef CustomSectionName) {
1505   switch (ID) {
1506   case wasm::WASM_SEC_CUSTOM:
1507     return StringSwitch<unsigned>(CustomSectionName)
1508         .Case("dylink", WASM_SEC_ORDER_DYLINK)
1509         .Case("linking", WASM_SEC_ORDER_LINKING)
1510         .StartsWith("reloc.", WASM_SEC_ORDER_RELOC)
1511         .Case("name", WASM_SEC_ORDER_NAME)
1512         .Case("producers", WASM_SEC_ORDER_PRODUCERS)
1513         .Default(-1);
1514   case wasm::WASM_SEC_TYPE:
1515     return WASM_SEC_ORDER_TYPE;
1516   case wasm::WASM_SEC_IMPORT:
1517     return WASM_SEC_ORDER_IMPORT;
1518   case wasm::WASM_SEC_FUNCTION:
1519     return WASM_SEC_ORDER_FUNCTION;
1520   case wasm::WASM_SEC_TABLE:
1521     return WASM_SEC_ORDER_TABLE;
1522   case wasm::WASM_SEC_MEMORY:
1523     return WASM_SEC_ORDER_MEMORY;
1524   case wasm::WASM_SEC_GLOBAL:
1525     return WASM_SEC_ORDER_GLOBAL;
1526   case wasm::WASM_SEC_EXPORT:
1527     return WASM_SEC_ORDER_EXPORT;
1528   case wasm::WASM_SEC_START:
1529     return WASM_SEC_ORDER_START;
1530   case wasm::WASM_SEC_ELEM:
1531     return WASM_SEC_ORDER_ELEM;
1532   case wasm::WASM_SEC_CODE:
1533     return WASM_SEC_ORDER_CODE;
1534   case wasm::WASM_SEC_DATA:
1535     return WASM_SEC_ORDER_DATA;
1536   case wasm::WASM_SEC_DATACOUNT:
1537     return WASM_SEC_ORDER_DATACOUNT;
1538   case wasm::WASM_SEC_EVENT:
1539     return WASM_SEC_ORDER_EVENT;
1540   default:
1541     llvm_unreachable("invalid section");
1542   }
1543 }
1544
1545 bool WasmSectionOrderChecker::isValidSectionOrder(unsigned ID,
1546                                                   StringRef CustomSectionName) {
1547   int Order = getSectionOrder(ID, CustomSectionName);
1548   if (Order == -1) // Skip unknown sections
1549     return true;
1550   // There can be multiple "reloc." sections. Otherwise there shouldn't be any
1551   // duplicate section orders.
1552   bool IsValid = (LastOrder == Order && Order == WASM_SEC_ORDER_RELOC) ||
1553                  LastOrder < Order;
1554   LastOrder = Order;
1555   return IsValid;
1556 }