xref: /llvm-project/llvm/lib/Object/WasmObjectFile.cpp (revision 6a31a0d694a65f5cb11ae6d49c7fdb3f08b0d262) 
1 //===- WasmObjectFile.cpp - Wasm object file implementation ---------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "llvm/ADT/ArrayRef.h"
11 #include "llvm/ADT/DenseSet.h"
12 #include "llvm/ADT/STLExtras.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 <algorithm>
28 #include <cassert>
29 #include <cstdint>
30 #include <cstring>
31 #include <system_error>
32 
33 #define DEBUG_TYPE "wasm-object"
34 
35 using namespace llvm;
36 using namespace object;
37 
38 Expected<std::unique_ptr<WasmObjectFile>>
39 ObjectFile::createWasmObjectFile(MemoryBufferRef Buffer) {
40   Error Err = Error::success();
41   auto ObjectFile = llvm::make_unique<WasmObjectFile>(Buffer, Err);
42   if (Err)
43     return std::move(Err);
44 
45   return std::move(ObjectFile);
46 }
47 
48 #define VARINT7_MAX ((1<<7)-1)
49 #define VARINT7_MIN (-(1<<7))
50 #define VARUINT7_MAX (1<<7)
51 #define VARUINT1_MAX (1)
52 
53 static uint8_t readUint8(const uint8_t *&Ptr) { return *Ptr++; }
54 
55 static uint32_t readUint32(const uint8_t *&Ptr) {
56   uint32_t Result = support::endian::read32le(Ptr);
57   Ptr += sizeof(Result);
58   return Result;
59 }
60 
61 static int32_t readFloat32(const uint8_t *&Ptr) {
62   int32_t Result = 0;
63   memcpy(&Result, Ptr, sizeof(Result));
64   Ptr += sizeof(Result);
65   return Result;
66 }
67 
68 static int64_t readFloat64(const uint8_t *&Ptr) {
69   int64_t Result = 0;
70   memcpy(&Result, Ptr, sizeof(Result));
71   Ptr += sizeof(Result);
72   return Result;
73 }
74 
75 static uint64_t readULEB128(const uint8_t *&Ptr) {
76   unsigned Count;
77   uint64_t Result = decodeULEB128(Ptr, &Count);
78   Ptr += Count;
79   return Result;
80 }
81 
82 static StringRef readString(const uint8_t *&Ptr) {
83   uint32_t StringLen = readULEB128(Ptr);
84   StringRef Return = StringRef(reinterpret_cast<const char *>(Ptr), StringLen);
85   Ptr += StringLen;
86   return Return;
87 }
88 
89 static int64_t readLEB128(const uint8_t *&Ptr) {
90   unsigned Count;
91   uint64_t Result = decodeSLEB128(Ptr, &Count);
92   Ptr += Count;
93   return Result;
94 }
95 
96 static uint8_t readVaruint1(const uint8_t *&Ptr) {
97   int64_t result = readLEB128(Ptr);
98   assert(result <= VARUINT1_MAX && result >= 0);
99   return result;
100 }
101 
102 static int32_t readVarint32(const uint8_t *&Ptr) {
103   int64_t result = readLEB128(Ptr);
104   assert(result <= INT32_MAX && result >= INT32_MIN);
105   return result;
106 }
107 
108 static uint32_t readVaruint32(const uint8_t *&Ptr) {
109   uint64_t result = readULEB128(Ptr);
110   assert(result <= UINT32_MAX);
111   return result;
112 }
113 
114 static int64_t readVarint64(const uint8_t *&Ptr) {
115   return readLEB128(Ptr);
116 }
117 
118 static uint8_t readOpcode(const uint8_t *&Ptr) {
119   return readUint8(Ptr);
120 }
121 
122 static Error readInitExpr(wasm::WasmInitExpr &Expr, const uint8_t *&Ptr) {
123   Expr.Opcode = readOpcode(Ptr);
124 
125   switch (Expr.Opcode) {
126   case wasm::WASM_OPCODE_I32_CONST:
127     Expr.Value.Int32 = readVarint32(Ptr);
128     break;
129   case wasm::WASM_OPCODE_I64_CONST:
130     Expr.Value.Int64 = readVarint64(Ptr);
131     break;
132   case wasm::WASM_OPCODE_F32_CONST:
133     Expr.Value.Float32 = readFloat32(Ptr);
134     break;
135   case wasm::WASM_OPCODE_F64_CONST:
136     Expr.Value.Float64 = readFloat64(Ptr);
137     break;
138   case wasm::WASM_OPCODE_GET_GLOBAL:
139     Expr.Value.Global = readULEB128(Ptr);
140     break;
141   default:
142     return make_error<GenericBinaryError>("Invalid opcode in init_expr",
143                                           object_error::parse_failed);
144   }
145 
146   uint8_t EndOpcode = readOpcode(Ptr);
147   if (EndOpcode != wasm::WASM_OPCODE_END) {
148     return make_error<GenericBinaryError>("Invalid init_expr",
149                                           object_error::parse_failed);
150   }
151   return Error::success();
152 }
153 
154 static wasm::WasmLimits readLimits(const uint8_t *&Ptr) {
155   wasm::WasmLimits Result;
156   Result.Flags = readVaruint1(Ptr);
157   Result.Initial = readVaruint32(Ptr);
158   if (Result.Flags & wasm::WASM_LIMITS_FLAG_HAS_MAX)
159     Result.Maximum = readVaruint32(Ptr);
160   return Result;
161 }
162 
163 static wasm::WasmTable readTable(const uint8_t *&Ptr) {
164   wasm::WasmTable Table;
165   Table.ElemType = readUint8(Ptr);
166   Table.Limits = readLimits(Ptr);
167   return Table;
168 }
169 
170 static Error readSection(WasmSection &Section, const uint8_t *&Ptr,
171                          const uint8_t *Start, const uint8_t *Eof) {
172   Section.Offset = Ptr - Start;
173   Section.Type = readUint8(Ptr);
174   uint32_t Size = readVaruint32(Ptr);
175   if (Size == 0)
176     return make_error<StringError>("Zero length section",
177                                    object_error::parse_failed);
178   if (Ptr + Size > Eof)
179     return make_error<StringError>("Section too large",
180                                    object_error::parse_failed);
181   if (Section.Type == wasm::WASM_SEC_CUSTOM) {
182     const uint8_t *NameStart = Ptr;
183     Section.Name = readString(Ptr);
184     Size -= Ptr - NameStart;
185   }
186   Section.Content = ArrayRef<uint8_t>(Ptr, Size);
187   Ptr += Size;
188   return Error::success();
189 }
190 
191 WasmObjectFile::WasmObjectFile(MemoryBufferRef Buffer, Error &Err)
192     : ObjectFile(Binary::ID_Wasm, Buffer) {
193   ErrorAsOutParameter ErrAsOutParam(&Err);
194   Header.Magic = getData().substr(0, 4);
195   if (Header.Magic != StringRef("\0asm", 4)) {
196     Err = make_error<StringError>("Bad magic number",
197                                   object_error::parse_failed);
198     return;
199   }
200 
201   const uint8_t *Eof = getPtr(getData().size());
202   const uint8_t *Ptr = getPtr(4);
203 
204   if (Ptr + 4 > Eof) {
205     Err = make_error<StringError>("Missing version number",
206                                   object_error::parse_failed);
207     return;
208   }
209 
210   Header.Version = readUint32(Ptr);
211   if (Header.Version != wasm::WasmVersion) {
212     Err = make_error<StringError>("Bad version number",
213                                   object_error::parse_failed);
214     return;
215   }
216 
217   WasmSection Sec;
218   while (Ptr < Eof) {
219     if ((Err = readSection(Sec, Ptr, getPtr(0), Eof)))
220       return;
221     if ((Err = parseSection(Sec)))
222       return;
223 
224     Sections.push_back(Sec);
225   }
226 }
227 
228 Error WasmObjectFile::parseSection(WasmSection &Sec) {
229   const uint8_t* Start = Sec.Content.data();
230   const uint8_t* End = Start + Sec.Content.size();
231   switch (Sec.Type) {
232   case wasm::WASM_SEC_CUSTOM:
233     return parseCustomSection(Sec, Start, End);
234   case wasm::WASM_SEC_TYPE:
235     return parseTypeSection(Start, End);
236   case wasm::WASM_SEC_IMPORT:
237     return parseImportSection(Start, End);
238   case wasm::WASM_SEC_FUNCTION:
239     return parseFunctionSection(Start, End);
240   case wasm::WASM_SEC_TABLE:
241     return parseTableSection(Start, End);
242   case wasm::WASM_SEC_MEMORY:
243     return parseMemorySection(Start, End);
244   case wasm::WASM_SEC_GLOBAL:
245     return parseGlobalSection(Start, End);
246   case wasm::WASM_SEC_EXPORT:
247     return parseExportSection(Start, End);
248   case wasm::WASM_SEC_START:
249     return parseStartSection(Start, End);
250   case wasm::WASM_SEC_ELEM:
251     return parseElemSection(Start, End);
252   case wasm::WASM_SEC_CODE:
253     return parseCodeSection(Start, End);
254   case wasm::WASM_SEC_DATA:
255     return parseDataSection(Start, End);
256   default:
257     return make_error<GenericBinaryError>("Bad section type",
258                                           object_error::parse_failed);
259   }
260 }
261 
262 Error WasmObjectFile::parseNameSection(const uint8_t *Ptr, const uint8_t *End) {
263   llvm::DenseSet<uint64_t> Seen;
264   if (Functions.size() != FunctionTypes.size()) {
265     return make_error<GenericBinaryError>("Names must come after code section",
266                                           object_error::parse_failed);
267   }
268 
269   while (Ptr < End) {
270     uint8_t Type = readUint8(Ptr);
271     uint32_t Size = readVaruint32(Ptr);
272     const uint8_t *SubSectionEnd = Ptr + Size;
273     switch (Type) {
274     case wasm::WASM_NAMES_FUNCTION: {
275       uint32_t Count = readVaruint32(Ptr);
276       while (Count--) {
277         uint32_t Index = readVaruint32(Ptr);
278         if (!Seen.insert(Index).second)
279           return make_error<GenericBinaryError>("Function named more than once",
280                                                 object_error::parse_failed);
281         StringRef Name = readString(Ptr);
282         if (!isValidFunctionIndex(Index) || Name.empty())
283           return make_error<GenericBinaryError>("Invalid name entry",
284                                                 object_error::parse_failed);
285         DebugNames.push_back(wasm::WasmFunctionName{Index, Name});
286         if (isDefinedFunctionIndex(Index))
287           getDefinedFunction(Index).DebugName = Name;
288       }
289       break;
290     }
291     // Ignore local names for now
292     case wasm::WASM_NAMES_LOCAL:
293     default:
294       Ptr += Size;
295       break;
296     }
297     if (Ptr != SubSectionEnd)
298       return make_error<GenericBinaryError>("Name sub-section ended prematurely",
299                                             object_error::parse_failed);
300   }
301 
302   if (Ptr != End)
303     return make_error<GenericBinaryError>("Name section ended prematurely",
304                                           object_error::parse_failed);
305   return Error::success();
306 }
307 
308 Error WasmObjectFile::parseLinkingSection(const uint8_t *Ptr,
309                                           const uint8_t *End) {
310   HasLinkingSection = true;
311   if (Functions.size() != FunctionTypes.size()) {
312     return make_error<GenericBinaryError>(
313         "Linking data must come after code section", object_error::parse_failed);
314   }
315 
316   LinkingData.Version = readVaruint32(Ptr);
317   if (LinkingData.Version != wasm::WasmMetadataVersion) {
318     return make_error<GenericBinaryError>(
319         "Unexpected metadata version: " + Twine(LinkingData.Version) +
320             " (Expected: " + Twine(wasm::WasmMetadataVersion) + ")",
321         object_error::parse_failed);
322   }
323 
324   while (Ptr < End) {
325     uint8_t Type = readUint8(Ptr);
326     uint32_t Size = readVaruint32(Ptr);
327     const uint8_t *SubSectionEnd = Ptr + Size;
328     switch (Type) {
329     case wasm::WASM_SYMBOL_TABLE:
330       if (Error Err = parseLinkingSectionSymtab(Ptr, SubSectionEnd))
331         return Err;
332       break;
333     case wasm::WASM_SEGMENT_INFO: {
334       uint32_t Count = readVaruint32(Ptr);
335       if (Count > DataSegments.size())
336         return make_error<GenericBinaryError>("Too many segment names",
337                                               object_error::parse_failed);
338       for (uint32_t i = 0; i < Count; i++) {
339         DataSegments[i].Data.Name = readString(Ptr);
340         DataSegments[i].Data.Alignment = readVaruint32(Ptr);
341         DataSegments[i].Data.Flags = readVaruint32(Ptr);
342       }
343       break;
344     }
345     case wasm::WASM_INIT_FUNCS: {
346       uint32_t Count = readVaruint32(Ptr);
347       LinkingData.InitFunctions.reserve(Count);
348       for (uint32_t i = 0; i < Count; i++) {
349         wasm::WasmInitFunc Init;
350         Init.Priority = readVaruint32(Ptr);
351         Init.Symbol = readVaruint32(Ptr);
352         if (!isValidFunctionSymbol(Init.Symbol))
353           return make_error<GenericBinaryError>("Invalid function symbol: " +
354                                                     Twine(Init.Symbol),
355                                                 object_error::parse_failed);
356         LinkingData.InitFunctions.emplace_back(Init);
357       }
358       break;
359     }
360     case wasm::WASM_COMDAT_INFO:
361       if (Error Err = parseLinkingSectionComdat(Ptr, SubSectionEnd))
362         return Err;
363       break;
364     default:
365       Ptr += Size;
366       break;
367     }
368     if (Ptr != SubSectionEnd)
369       return make_error<GenericBinaryError>(
370           "Linking sub-section ended prematurely", object_error::parse_failed);
371   }
372   if (Ptr != End)
373     return make_error<GenericBinaryError>("Linking section ended prematurely",
374                                           object_error::parse_failed);
375   return Error::success();
376 }
377 
378 Error WasmObjectFile::parseLinkingSectionSymtab(const uint8_t *&Ptr,
379                                                 const uint8_t *End) {
380   uint32_t Count = readVaruint32(Ptr);
381   LinkingData.SymbolTable.reserve(Count);
382   Symbols.reserve(Count);
383   StringSet<> SymbolNames;
384 
385   std::vector<wasm::WasmImport *> ImportedGlobals;
386   std::vector<wasm::WasmImport *> ImportedFunctions;
387   ImportedGlobals.reserve(Imports.size());
388   ImportedFunctions.reserve(Imports.size());
389   for (auto &I : Imports) {
390     if (I.Kind == wasm::WASM_EXTERNAL_FUNCTION)
391       ImportedFunctions.emplace_back(&I);
392     else if (I.Kind == wasm::WASM_EXTERNAL_GLOBAL)
393       ImportedGlobals.emplace_back(&I);
394   }
395 
396   while (Count--) {
397     wasm::WasmSymbolInfo Info;
398     const wasm::WasmSignature *FunctionType = nullptr;
399     const wasm::WasmGlobalType *GlobalType = nullptr;
400 
401     Info.Kind = readUint8(Ptr);
402     Info.Flags = readVaruint32(Ptr);
403     bool IsDefined = (Info.Flags & wasm::WASM_SYMBOL_UNDEFINED) == 0;
404 
405     switch (Info.Kind) {
406     case wasm::WASM_SYMBOL_TYPE_FUNCTION:
407       Info.ElementIndex = readVaruint32(Ptr);
408       if (!isValidFunctionIndex(Info.ElementIndex) ||
409           IsDefined != isDefinedFunctionIndex(Info.ElementIndex))
410         return make_error<GenericBinaryError>("invalid function symbol index",
411                                               object_error::parse_failed);
412       if (IsDefined) {
413         Info.Name = readString(Ptr);
414         unsigned FuncIndex = Info.ElementIndex - NumImportedFunctions;
415         FunctionType = &Signatures[FunctionTypes[FuncIndex]];
416         wasm::WasmFunction &Function = Functions[FuncIndex];
417         if (Function.SymbolName.empty())
418           Function.SymbolName = Info.Name;
419       } else {
420         wasm::WasmImport &Import = *ImportedFunctions[Info.ElementIndex];
421         FunctionType = &Signatures[Import.SigIndex];
422         Info.Name = Import.Field;
423         Info.Module = Import.Module;
424       }
425       break;
426 
427     case wasm::WASM_SYMBOL_TYPE_GLOBAL:
428       Info.ElementIndex = readVaruint32(Ptr);
429       if (!isValidGlobalIndex(Info.ElementIndex) ||
430           IsDefined != isDefinedGlobalIndex(Info.ElementIndex))
431         return make_error<GenericBinaryError>("invalid global symbol index",
432                                               object_error::parse_failed);
433       if (!IsDefined &&
434           (Info.Flags & wasm::WASM_SYMBOL_BINDING_MASK) ==
435               wasm::WASM_SYMBOL_BINDING_WEAK)
436         return make_error<GenericBinaryError>("undefined weak global symbol",
437                                               object_error::parse_failed);
438       if (IsDefined) {
439         Info.Name = readString(Ptr);
440         unsigned GlobalIndex = Info.ElementIndex - NumImportedGlobals;
441         wasm::WasmGlobal &Global = Globals[GlobalIndex];
442         GlobalType = &Global.Type;
443         if (Global.SymbolName.empty())
444           Global.SymbolName = Info.Name;
445       } else {
446         wasm::WasmImport &Import = *ImportedGlobals[Info.ElementIndex];
447         Info.Name = Import.Field;
448         GlobalType = &Import.Global;
449       }
450       break;
451 
452     case wasm::WASM_SYMBOL_TYPE_DATA:
453       Info.Name = readString(Ptr);
454       if (IsDefined) {
455         uint32_t Index = readVaruint32(Ptr);
456         if (Index >= DataSegments.size())
457           return make_error<GenericBinaryError>("invalid data symbol index",
458                                                 object_error::parse_failed);
459         uint32_t Offset = readVaruint32(Ptr);
460         uint32_t Size = readVaruint32(Ptr);
461         if (Offset + Size > DataSegments[Index].Data.Content.size())
462           return make_error<GenericBinaryError>("invalid data symbol offset",
463                                                 object_error::parse_failed);
464         Info.DataRef = wasm::WasmDataReference{Index, Offset, Size};
465       }
466       break;
467 
468     case wasm::WASM_SYMBOL_TYPE_SECTION: {
469       Info.ElementIndex = readVaruint32(Ptr);
470       // Use somewhat unique section name as symbol name.
471       StringRef SectionName = Sections[Info.ElementIndex].Name;
472       Info.Name = SectionName;
473       break;
474     }
475 
476     default:
477       return make_error<GenericBinaryError>("Invalid symbol type",
478                                             object_error::parse_failed);
479     }
480 
481     if ((Info.Flags & wasm::WASM_SYMBOL_BINDING_MASK) !=
482             wasm::WASM_SYMBOL_BINDING_LOCAL &&
483         !SymbolNames.insert(Info.Name).second)
484       return make_error<GenericBinaryError>("Duplicate symbol name " +
485                                                 Twine(Info.Name),
486                                             object_error::parse_failed);
487     LinkingData.SymbolTable.emplace_back(Info);
488     Symbols.emplace_back(LinkingData.SymbolTable.back(), FunctionType,
489                          GlobalType);
490     DEBUG(dbgs() << "Adding symbol: " << Symbols.back() << "\n");
491   }
492 
493   return Error::success();
494 }
495 
496 Error WasmObjectFile::parseLinkingSectionComdat(const uint8_t *&Ptr,
497                                                 const uint8_t *End)
498 {
499   uint32_t ComdatCount = readVaruint32(Ptr);
500   StringSet<> ComdatSet;
501   for (unsigned ComdatIndex = 0; ComdatIndex < ComdatCount; ++ComdatIndex) {
502     StringRef Name = readString(Ptr);
503     if (Name.empty() || !ComdatSet.insert(Name).second)
504       return make_error<GenericBinaryError>("Bad/duplicate COMDAT name " + Twine(Name),
505                                             object_error::parse_failed);
506     LinkingData.Comdats.emplace_back(Name);
507     uint32_t Flags = readVaruint32(Ptr);
508     if (Flags != 0)
509       return make_error<GenericBinaryError>("Unsupported COMDAT flags",
510                                             object_error::parse_failed);
511 
512     uint32_t EntryCount = readVaruint32(Ptr);
513     while (EntryCount--) {
514       unsigned Kind = readVaruint32(Ptr);
515       unsigned Index = readVaruint32(Ptr);
516       switch (Kind) {
517       default:
518         return make_error<GenericBinaryError>("Invalid COMDAT entry type",
519                                               object_error::parse_failed);
520       case wasm::WASM_COMDAT_DATA:
521         if (Index >= DataSegments.size())
522           return make_error<GenericBinaryError>("COMDAT data index out of range",
523                                                 object_error::parse_failed);
524         if (DataSegments[Index].Data.Comdat != UINT32_MAX)
525           return make_error<GenericBinaryError>("Data segment in two COMDATs",
526                                                 object_error::parse_failed);
527         DataSegments[Index].Data.Comdat = ComdatIndex;
528         break;
529       case wasm::WASM_COMDAT_FUNCTION:
530         if (!isDefinedFunctionIndex(Index))
531           return make_error<GenericBinaryError>("COMDAT function index out of range",
532                                                 object_error::parse_failed);
533         if (getDefinedFunction(Index).Comdat != UINT32_MAX)
534           return make_error<GenericBinaryError>("Function in two COMDATs",
535                                                 object_error::parse_failed);
536         getDefinedFunction(Index).Comdat = ComdatIndex;
537         break;
538       }
539     }
540   }
541   return Error::success();
542 }
543 
544 Error WasmObjectFile::parseRelocSection(StringRef Name, const uint8_t *Ptr,
545                                         const uint8_t *End) {
546   uint32_t SectionIndex = readVaruint32(Ptr);
547   if (SectionIndex >= Sections.size())
548     return make_error<GenericBinaryError>("Invalid section index",
549                                           object_error::parse_failed);
550   WasmSection& Section = Sections[SectionIndex];
551   uint32_t RelocCount = readVaruint32(Ptr);
552   uint32_t EndOffset = Section.Content.size();
553   while (RelocCount--) {
554     wasm::WasmRelocation Reloc = {};
555     Reloc.Type = readVaruint32(Ptr);
556     Reloc.Offset = readVaruint32(Ptr);
557     Reloc.Index = readVaruint32(Ptr);
558     switch (Reloc.Type) {
559     case wasm::R_WEBASSEMBLY_FUNCTION_INDEX_LEB:
560     case wasm::R_WEBASSEMBLY_TABLE_INDEX_SLEB:
561     case wasm::R_WEBASSEMBLY_TABLE_INDEX_I32:
562       if (!isValidFunctionSymbol(Reloc.Index))
563         return make_error<GenericBinaryError>("Bad relocation function index",
564                                               object_error::parse_failed);
565       break;
566     case wasm::R_WEBASSEMBLY_TYPE_INDEX_LEB:
567       if (Reloc.Index >= Signatures.size())
568         return make_error<GenericBinaryError>("Bad relocation type index",
569                                               object_error::parse_failed);
570       break;
571     case wasm::R_WEBASSEMBLY_GLOBAL_INDEX_LEB:
572       if (!isValidGlobalSymbol(Reloc.Index))
573         return make_error<GenericBinaryError>("Bad relocation global index",
574                                               object_error::parse_failed);
575       break;
576     case wasm::R_WEBASSEMBLY_MEMORY_ADDR_LEB:
577     case wasm::R_WEBASSEMBLY_MEMORY_ADDR_SLEB:
578     case wasm::R_WEBASSEMBLY_MEMORY_ADDR_I32:
579       if (!isValidDataSymbol(Reloc.Index))
580         return make_error<GenericBinaryError>("Bad relocation data index",
581                                               object_error::parse_failed);
582       Reloc.Addend = readVarint32(Ptr);
583       break;
584     case wasm::R_WEBASSEMBLY_FUNCTION_OFFSET_I32:
585       if (!isValidFunctionSymbol(Reloc.Index))
586         return make_error<GenericBinaryError>("Bad relocation function index",
587                                               object_error::parse_failed);
588       Reloc.Addend = readVarint32(Ptr);
589       break;
590     case wasm::R_WEBASSEMBLY_SECTION_OFFSET_I32:
591       if (!isValidSectionSymbol(Reloc.Index))
592         return make_error<GenericBinaryError>("Bad relocation section index",
593                                               object_error::parse_failed);
594       Reloc.Addend = readVarint32(Ptr);
595       break;
596     default:
597       return make_error<GenericBinaryError>("Bad relocation type: " +
598                                                 Twine(Reloc.Type),
599                                             object_error::parse_failed);
600     }
601 
602     // Relocations must fit inside the section, and must appear in order.  They
603     // also shouldn't overlap a function/element boundary, but we don't bother
604     // to check that.
605     uint64_t Size = 5;
606     if (Reloc.Type == wasm::R_WEBASSEMBLY_TABLE_INDEX_I32 ||
607         Reloc.Type == wasm::R_WEBASSEMBLY_MEMORY_ADDR_I32 ||
608         Reloc.Type == wasm::R_WEBASSEMBLY_SECTION_OFFSET_I32 ||
609         Reloc.Type == wasm::R_WEBASSEMBLY_FUNCTION_OFFSET_I32)
610       Size = 4;
611     if (Reloc.Offset + Size > EndOffset)
612       return make_error<GenericBinaryError>("Bad relocation offset",
613                                             object_error::parse_failed);
614 
615     Section.Relocations.push_back(Reloc);
616   }
617   if (Ptr != End)
618     return make_error<GenericBinaryError>("Reloc section ended prematurely",
619                                           object_error::parse_failed);
620   return Error::success();
621 }
622 
623 Error WasmObjectFile::parseCustomSection(WasmSection &Sec,
624                                          const uint8_t *Ptr, const uint8_t *End) {
625   if (Sec.Name == "name") {
626     if (Error Err = parseNameSection(Ptr, End))
627       return Err;
628   } else if (Sec.Name == "linking") {
629     if (Error Err = parseLinkingSection(Ptr, End))
630       return Err;
631   } else if (Sec.Name.startswith("reloc.")) {
632     if (Error Err = parseRelocSection(Sec.Name, Ptr, End))
633       return Err;
634   }
635   return Error::success();
636 }
637 
638 Error WasmObjectFile::parseTypeSection(const uint8_t *Ptr, const uint8_t *End) {
639   uint32_t Count = readVaruint32(Ptr);
640   Signatures.reserve(Count);
641   while (Count--) {
642     wasm::WasmSignature Sig;
643     Sig.ReturnType = wasm::WASM_TYPE_NORESULT;
644     uint8_t Form = readUint8(Ptr);
645     if (Form != wasm::WASM_TYPE_FUNC) {
646       return make_error<GenericBinaryError>("Invalid signature type",
647                                             object_error::parse_failed);
648     }
649     uint32_t ParamCount = readVaruint32(Ptr);
650     Sig.ParamTypes.reserve(ParamCount);
651     while (ParamCount--) {
652       uint32_t ParamType = readUint8(Ptr);
653       Sig.ParamTypes.push_back(ParamType);
654     }
655     uint32_t ReturnCount = readVaruint32(Ptr);
656     if (ReturnCount) {
657       if (ReturnCount != 1) {
658         return make_error<GenericBinaryError>(
659             "Multiple return types not supported", object_error::parse_failed);
660       }
661       Sig.ReturnType = readUint8(Ptr);
662     }
663     Signatures.push_back(Sig);
664   }
665   if (Ptr != End)
666     return make_error<GenericBinaryError>("Type section ended prematurely",
667                                           object_error::parse_failed);
668   return Error::success();
669 }
670 
671 Error WasmObjectFile::parseImportSection(const uint8_t *Ptr, const uint8_t *End) {
672   uint32_t Count = readVaruint32(Ptr);
673   Imports.reserve(Count);
674   for (uint32_t i = 0; i < Count; i++) {
675     wasm::WasmImport Im;
676     Im.Module = readString(Ptr);
677     Im.Field = readString(Ptr);
678     Im.Kind = readUint8(Ptr);
679     switch (Im.Kind) {
680     case wasm::WASM_EXTERNAL_FUNCTION:
681       NumImportedFunctions++;
682       Im.SigIndex = readVaruint32(Ptr);
683       break;
684     case wasm::WASM_EXTERNAL_GLOBAL:
685       NumImportedGlobals++;
686       Im.Global.Type = readUint8(Ptr);
687       Im.Global.Mutable = readVaruint1(Ptr);
688       break;
689     case wasm::WASM_EXTERNAL_MEMORY:
690       Im.Memory = readLimits(Ptr);
691       break;
692     case wasm::WASM_EXTERNAL_TABLE:
693       Im.Table = readTable(Ptr);
694       if (Im.Table.ElemType != wasm::WASM_TYPE_ANYFUNC)
695         return make_error<GenericBinaryError>("Invalid table element type",
696                                               object_error::parse_failed);
697       break;
698     default:
699       return make_error<GenericBinaryError>(
700           "Unexpected import kind", object_error::parse_failed);
701     }
702     Imports.push_back(Im);
703   }
704   if (Ptr != End)
705     return make_error<GenericBinaryError>("Import section ended prematurely",
706                                           object_error::parse_failed);
707   return Error::success();
708 }
709 
710 Error WasmObjectFile::parseFunctionSection(const uint8_t *Ptr, const uint8_t *End) {
711   uint32_t Count = readVaruint32(Ptr);
712   FunctionTypes.reserve(Count);
713   uint32_t NumTypes = Signatures.size();
714   while (Count--) {
715     uint32_t Type = readVaruint32(Ptr);
716     if (Type >= NumTypes)
717       return make_error<GenericBinaryError>("Invalid function type",
718                                             object_error::parse_failed);
719     FunctionTypes.push_back(Type);
720   }
721   if (Ptr != End)
722     return make_error<GenericBinaryError>("Function section ended prematurely",
723                                           object_error::parse_failed);
724   return Error::success();
725 }
726 
727 Error WasmObjectFile::parseTableSection(const uint8_t *Ptr, const uint8_t *End) {
728   uint32_t Count = readVaruint32(Ptr);
729   Tables.reserve(Count);
730   while (Count--) {
731     Tables.push_back(readTable(Ptr));
732     if (Tables.back().ElemType != wasm::WASM_TYPE_ANYFUNC) {
733       return make_error<GenericBinaryError>("Invalid table element type",
734                                             object_error::parse_failed);
735     }
736   }
737   if (Ptr != End)
738     return make_error<GenericBinaryError>("Table section ended prematurely",
739                                           object_error::parse_failed);
740   return Error::success();
741 }
742 
743 Error WasmObjectFile::parseMemorySection(const uint8_t *Ptr, const uint8_t *End) {
744   uint32_t Count = readVaruint32(Ptr);
745   Memories.reserve(Count);
746   while (Count--) {
747     Memories.push_back(readLimits(Ptr));
748   }
749   if (Ptr != End)
750     return make_error<GenericBinaryError>("Memory section ended prematurely",
751                                           object_error::parse_failed);
752   return Error::success();
753 }
754 
755 Error WasmObjectFile::parseGlobalSection(const uint8_t *Ptr, const uint8_t *End) {
756   GlobalSection = Sections.size();
757   uint32_t Count = readVaruint32(Ptr);
758   Globals.reserve(Count);
759   while (Count--) {
760     wasm::WasmGlobal Global;
761     Global.Index = NumImportedGlobals + Globals.size();
762     Global.Type.Type = readUint8(Ptr);
763     Global.Type.Mutable = readVaruint1(Ptr);
764     if (Error Err = readInitExpr(Global.InitExpr, Ptr))
765       return Err;
766     Globals.push_back(Global);
767   }
768   if (Ptr != End)
769     return make_error<GenericBinaryError>("Global section ended prematurely",
770                                           object_error::parse_failed);
771   return Error::success();
772 }
773 
774 Error WasmObjectFile::parseExportSection(const uint8_t *Ptr, const uint8_t *End) {
775   uint32_t Count = readVaruint32(Ptr);
776   Exports.reserve(Count);
777   for (uint32_t i = 0; i < Count; i++) {
778     wasm::WasmExport Ex;
779     Ex.Name = readString(Ptr);
780     Ex.Kind = readUint8(Ptr);
781     Ex.Index = readVaruint32(Ptr);
782     switch (Ex.Kind) {
783     case wasm::WASM_EXTERNAL_FUNCTION:
784       if (!isValidFunctionIndex(Ex.Index))
785         return make_error<GenericBinaryError>("Invalid function export",
786                                               object_error::parse_failed);
787       break;
788     case wasm::WASM_EXTERNAL_GLOBAL:
789       if (!isValidGlobalIndex(Ex.Index))
790         return make_error<GenericBinaryError>("Invalid global export",
791                                               object_error::parse_failed);
792       break;
793     case wasm::WASM_EXTERNAL_MEMORY:
794     case wasm::WASM_EXTERNAL_TABLE:
795       break;
796     default:
797       return make_error<GenericBinaryError>(
798           "Unexpected export kind", object_error::parse_failed);
799     }
800     Exports.push_back(Ex);
801   }
802   if (Ptr != End)
803     return make_error<GenericBinaryError>("Export section ended prematurely",
804                                           object_error::parse_failed);
805   return Error::success();
806 }
807 
808 bool WasmObjectFile::isValidFunctionIndex(uint32_t Index) const {
809   return Index < NumImportedFunctions + FunctionTypes.size();
810 }
811 
812 bool WasmObjectFile::isDefinedFunctionIndex(uint32_t Index) const {
813   return Index >= NumImportedFunctions && isValidFunctionIndex(Index);
814 }
815 
816 bool WasmObjectFile::isValidGlobalIndex(uint32_t Index) const {
817   return Index < NumImportedGlobals + Globals.size();
818 }
819 
820 bool WasmObjectFile::isDefinedGlobalIndex(uint32_t Index) const {
821   return Index >= NumImportedGlobals && isValidGlobalIndex(Index);
822 }
823 
824 bool WasmObjectFile::isValidFunctionSymbol(uint32_t Index) const {
825   return Index < Symbols.size() && Symbols[Index].isTypeFunction();
826 }
827 
828 bool WasmObjectFile::isValidGlobalSymbol(uint32_t Index) const {
829   return Index < Symbols.size() && Symbols[Index].isTypeGlobal();
830 }
831 
832 bool WasmObjectFile::isValidDataSymbol(uint32_t Index) const {
833   return Index < Symbols.size() && Symbols[Index].isTypeData();
834 }
835 
836 bool WasmObjectFile::isValidSectionSymbol(uint32_t Index) const {
837   return Index < Symbols.size() && Symbols[Index].isTypeSection();
838 }
839 
840 wasm::WasmFunction &WasmObjectFile::getDefinedFunction(uint32_t Index) {
841   assert(isDefinedFunctionIndex(Index));
842   return Functions[Index - NumImportedFunctions];
843 }
844 
845 wasm::WasmGlobal &WasmObjectFile::getDefinedGlobal(uint32_t Index) {
846   assert(isDefinedGlobalIndex(Index));
847   return Globals[Index - NumImportedGlobals];
848 }
849 
850 Error WasmObjectFile::parseStartSection(const uint8_t *Ptr, const uint8_t *End) {
851   StartFunction = readVaruint32(Ptr);
852   if (!isValidFunctionIndex(StartFunction))
853     return make_error<GenericBinaryError>("Invalid start function",
854                                           object_error::parse_failed);
855   return Error::success();
856 }
857 
858 Error WasmObjectFile::parseCodeSection(const uint8_t *Ptr, const uint8_t *End) {
859   CodeSection = Sections.size();
860   const uint8_t *CodeSectionStart = Ptr;
861   uint32_t FunctionCount = readVaruint32(Ptr);
862   if (FunctionCount != FunctionTypes.size()) {
863     return make_error<GenericBinaryError>("Invalid function count",
864                                           object_error::parse_failed);
865   }
866 
867   while (FunctionCount--) {
868     wasm::WasmFunction Function;
869     const uint8_t *FunctionStart = Ptr;
870     uint32_t Size = readVaruint32(Ptr);
871     const uint8_t *FunctionEnd = Ptr + Size;
872 
873     Function.Index = NumImportedFunctions + Functions.size();
874     Function.CodeSectionOffset = FunctionStart - CodeSectionStart;
875     Function.Size = FunctionEnd - FunctionStart;
876 
877     uint32_t NumLocalDecls = readVaruint32(Ptr);
878     Function.Locals.reserve(NumLocalDecls);
879     while (NumLocalDecls--) {
880       wasm::WasmLocalDecl Decl;
881       Decl.Count = readVaruint32(Ptr);
882       Decl.Type = readUint8(Ptr);
883       Function.Locals.push_back(Decl);
884     }
885 
886     uint32_t BodySize = FunctionEnd - Ptr;
887     Function.Body = ArrayRef<uint8_t>(Ptr, BodySize);
888     // This will be set later when reading in the linking metadata section.
889     Function.Comdat = UINT32_MAX;
890     Ptr += BodySize;
891     assert(Ptr == FunctionEnd);
892     Functions.push_back(Function);
893   }
894   if (Ptr != End)
895     return make_error<GenericBinaryError>("Code section ended prematurely",
896                                           object_error::parse_failed);
897   return Error::success();
898 }
899 
900 Error WasmObjectFile::parseElemSection(const uint8_t *Ptr, const uint8_t *End) {
901   uint32_t Count = readVaruint32(Ptr);
902   ElemSegments.reserve(Count);
903   while (Count--) {
904     wasm::WasmElemSegment Segment;
905     Segment.TableIndex = readVaruint32(Ptr);
906     if (Segment.TableIndex != 0) {
907       return make_error<GenericBinaryError>("Invalid TableIndex",
908                                             object_error::parse_failed);
909     }
910     if (Error Err = readInitExpr(Segment.Offset, Ptr))
911       return Err;
912     uint32_t NumElems = readVaruint32(Ptr);
913     while (NumElems--) {
914       Segment.Functions.push_back(readVaruint32(Ptr));
915     }
916     ElemSegments.push_back(Segment);
917   }
918   if (Ptr != End)
919     return make_error<GenericBinaryError>("Elem section ended prematurely",
920                                           object_error::parse_failed);
921   return Error::success();
922 }
923 
924 Error WasmObjectFile::parseDataSection(const uint8_t *Ptr, const uint8_t *End) {
925   DataSection = Sections.size();
926   const uint8_t *Start = Ptr;
927   uint32_t Count = readVaruint32(Ptr);
928   DataSegments.reserve(Count);
929   while (Count--) {
930     WasmSegment Segment;
931     Segment.Data.MemoryIndex = readVaruint32(Ptr);
932     if (Error Err = readInitExpr(Segment.Data.Offset, Ptr))
933       return Err;
934     uint32_t Size = readVaruint32(Ptr);
935     Segment.Data.Content = ArrayRef<uint8_t>(Ptr, Size);
936     // The rest of these Data fields are set later, when reading in the linking
937     // metadata section.
938     Segment.Data.Alignment = 0;
939     Segment.Data.Flags = 0;
940     Segment.Data.Comdat = UINT32_MAX;
941     Segment.SectionOffset = Ptr - Start;
942     Ptr += Size;
943     DataSegments.push_back(Segment);
944   }
945   if (Ptr != End)
946     return make_error<GenericBinaryError>("Data section ended prematurely",
947                                           object_error::parse_failed);
948   return Error::success();
949 }
950 
951 const uint8_t *WasmObjectFile::getPtr(size_t Offset) const {
952   return reinterpret_cast<const uint8_t *>(getData().substr(Offset, 1).data());
953 }
954 
955 const wasm::WasmObjectHeader &WasmObjectFile::getHeader() const {
956   return Header;
957 }
958 
959 void WasmObjectFile::moveSymbolNext(DataRefImpl &Symb) const { Symb.d.a++; }
960 
961 uint32_t WasmObjectFile::getSymbolFlags(DataRefImpl Symb) const {
962   uint32_t Result = SymbolRef::SF_None;
963   const WasmSymbol &Sym = getWasmSymbol(Symb);
964 
965   DEBUG(dbgs() << "getSymbolFlags: ptr=" << &Sym << " " << Sym << "\n");
966   if (Sym.isBindingWeak())
967     Result |= SymbolRef::SF_Weak;
968   if (!Sym.isBindingLocal())
969     Result |= SymbolRef::SF_Global;
970   if (Sym.isHidden())
971     Result |= SymbolRef::SF_Hidden;
972   if (!Sym.isDefined())
973     Result |= SymbolRef::SF_Undefined;
974   if (Sym.isTypeFunction())
975     Result |= SymbolRef::SF_Executable;
976   return Result;
977 }
978 
979 basic_symbol_iterator WasmObjectFile::symbol_begin() const {
980   DataRefImpl Ref;
981   Ref.d.a = 0;
982   return BasicSymbolRef(Ref, this);
983 }
984 
985 basic_symbol_iterator WasmObjectFile::symbol_end() const {
986   DataRefImpl Ref;
987   Ref.d.a = Symbols.size();
988   return BasicSymbolRef(Ref, this);
989 }
990 
991 const WasmSymbol &WasmObjectFile::getWasmSymbol(const DataRefImpl &Symb) const {
992   return Symbols[Symb.d.a];
993 }
994 
995 const WasmSymbol &WasmObjectFile::getWasmSymbol(const SymbolRef &Symb) const {
996   return getWasmSymbol(Symb.getRawDataRefImpl());
997 }
998 
999 Expected<StringRef> WasmObjectFile::getSymbolName(DataRefImpl Symb) const {
1000   return getWasmSymbol(Symb).Info.Name;
1001 }
1002 
1003 Expected<uint64_t> WasmObjectFile::getSymbolAddress(DataRefImpl Symb) const {
1004   return getSymbolValue(Symb);
1005 }
1006 
1007 uint64_t WasmObjectFile::getWasmSymbolValue(const WasmSymbol& Sym) const {
1008   switch (Sym.Info.Kind) {
1009   case wasm::WASM_SYMBOL_TYPE_FUNCTION:
1010   case wasm::WASM_SYMBOL_TYPE_GLOBAL:
1011     return Sym.Info.ElementIndex;
1012   case wasm::WASM_SYMBOL_TYPE_DATA: {
1013     // The value of a data symbol is the segment offset, plus the symbol
1014     // offset within the segment.
1015     uint32_t SegmentIndex = Sym.Info.DataRef.Segment;
1016     const wasm::WasmDataSegment &Segment = DataSegments[SegmentIndex].Data;
1017     assert(Segment.Offset.Opcode == wasm::WASM_OPCODE_I32_CONST);
1018     return Segment.Offset.Value.Int32 + Sym.Info.DataRef.Offset;
1019   }
1020   case wasm::WASM_SYMBOL_TYPE_SECTION:
1021     return 0;
1022   }
1023   llvm_unreachable("invalid symbol type");
1024 }
1025 
1026 uint64_t WasmObjectFile::getSymbolValueImpl(DataRefImpl Symb) const {
1027   return getWasmSymbolValue(getWasmSymbol(Symb));
1028 }
1029 
1030 uint32_t WasmObjectFile::getSymbolAlignment(DataRefImpl Symb) const {
1031   llvm_unreachable("not yet implemented");
1032   return 0;
1033 }
1034 
1035 uint64_t WasmObjectFile::getCommonSymbolSizeImpl(DataRefImpl Symb) const {
1036   llvm_unreachable("not yet implemented");
1037   return 0;
1038 }
1039 
1040 Expected<SymbolRef::Type>
1041 WasmObjectFile::getSymbolType(DataRefImpl Symb) const {
1042   const WasmSymbol &Sym = getWasmSymbol(Symb);
1043 
1044   switch (Sym.Info.Kind) {
1045   case wasm::WASM_SYMBOL_TYPE_FUNCTION:
1046     return SymbolRef::ST_Function;
1047   case wasm::WASM_SYMBOL_TYPE_GLOBAL:
1048     return SymbolRef::ST_Other;
1049   case wasm::WASM_SYMBOL_TYPE_DATA:
1050     return SymbolRef::ST_Data;
1051   case wasm::WASM_SYMBOL_TYPE_SECTION:
1052     return SymbolRef::ST_Debug;
1053   }
1054 
1055   llvm_unreachable("Unknown WasmSymbol::SymbolType");
1056   return SymbolRef::ST_Other;
1057 }
1058 
1059 Expected<section_iterator>
1060 WasmObjectFile::getSymbolSection(DataRefImpl Symb) const {
1061   const WasmSymbol& Sym = getWasmSymbol(Symb);
1062   if (Sym.isUndefined())
1063     return section_end();
1064 
1065   DataRefImpl Ref;
1066   switch (Sym.Info.Kind) {
1067   case wasm::WASM_SYMBOL_TYPE_FUNCTION:
1068     Ref.d.a = CodeSection;
1069     break;
1070   case wasm::WASM_SYMBOL_TYPE_GLOBAL:
1071     Ref.d.a = GlobalSection;
1072     break;
1073   case wasm::WASM_SYMBOL_TYPE_DATA:
1074     Ref.d.a = DataSection;
1075     break;
1076   case wasm::WASM_SYMBOL_TYPE_SECTION: {
1077     Ref.d.a = Sym.Info.ElementIndex;
1078     break;
1079   }
1080   default:
1081     llvm_unreachable("Unknown WasmSymbol::SymbolType");
1082   }
1083   return section_iterator(SectionRef(Ref, this));
1084 }
1085 
1086 void WasmObjectFile::moveSectionNext(DataRefImpl &Sec) const { Sec.d.a++; }
1087 
1088 std::error_code WasmObjectFile::getSectionName(DataRefImpl Sec,
1089                                                StringRef &Res) const {
1090   const WasmSection &S = Sections[Sec.d.a];
1091 #define ECase(X)                                                               \
1092   case wasm::WASM_SEC_##X:                                                     \
1093     Res = #X;                                                                  \
1094     break
1095   switch (S.Type) {
1096     ECase(TYPE);
1097     ECase(IMPORT);
1098     ECase(FUNCTION);
1099     ECase(TABLE);
1100     ECase(MEMORY);
1101     ECase(GLOBAL);
1102     ECase(EXPORT);
1103     ECase(START);
1104     ECase(ELEM);
1105     ECase(CODE);
1106     ECase(DATA);
1107   case wasm::WASM_SEC_CUSTOM:
1108     Res = S.Name;
1109     break;
1110   default:
1111     return object_error::invalid_section_index;
1112   }
1113 #undef ECase
1114   return std::error_code();
1115 }
1116 
1117 uint64_t WasmObjectFile::getSectionAddress(DataRefImpl Sec) const { return 0; }
1118 
1119 uint64_t WasmObjectFile::getSectionIndex(DataRefImpl Sec) const {
1120   return Sec.d.a;
1121 }
1122 
1123 uint64_t WasmObjectFile::getSectionSize(DataRefImpl Sec) const {
1124   const WasmSection &S = Sections[Sec.d.a];
1125   return S.Content.size();
1126 }
1127 
1128 std::error_code WasmObjectFile::getSectionContents(DataRefImpl Sec,
1129                                                    StringRef &Res) const {
1130   const WasmSection &S = Sections[Sec.d.a];
1131   // This will never fail since wasm sections can never be empty (user-sections
1132   // must have a name and non-user sections each have a defined structure).
1133   Res = StringRef(reinterpret_cast<const char *>(S.Content.data()),
1134                   S.Content.size());
1135   return std::error_code();
1136 }
1137 
1138 uint64_t WasmObjectFile::getSectionAlignment(DataRefImpl Sec) const {
1139   return 1;
1140 }
1141 
1142 bool WasmObjectFile::isSectionCompressed(DataRefImpl Sec) const {
1143   return false;
1144 }
1145 
1146 bool WasmObjectFile::isSectionText(DataRefImpl Sec) const {
1147   return getWasmSection(Sec).Type == wasm::WASM_SEC_CODE;
1148 }
1149 
1150 bool WasmObjectFile::isSectionData(DataRefImpl Sec) const {
1151   return getWasmSection(Sec).Type == wasm::WASM_SEC_DATA;
1152 }
1153 
1154 bool WasmObjectFile::isSectionBSS(DataRefImpl Sec) const { return false; }
1155 
1156 bool WasmObjectFile::isSectionVirtual(DataRefImpl Sec) const { return false; }
1157 
1158 bool WasmObjectFile::isSectionBitcode(DataRefImpl Sec) const { return false; }
1159 
1160 relocation_iterator WasmObjectFile::section_rel_begin(DataRefImpl Ref) const {
1161   DataRefImpl RelocRef;
1162   RelocRef.d.a = Ref.d.a;
1163   RelocRef.d.b = 0;
1164   return relocation_iterator(RelocationRef(RelocRef, this));
1165 }
1166 
1167 relocation_iterator WasmObjectFile::section_rel_end(DataRefImpl Ref) const {
1168   const WasmSection &Sec = getWasmSection(Ref);
1169   DataRefImpl RelocRef;
1170   RelocRef.d.a = Ref.d.a;
1171   RelocRef.d.b = Sec.Relocations.size();
1172   return relocation_iterator(RelocationRef(RelocRef, this));
1173 }
1174 
1175 void WasmObjectFile::moveRelocationNext(DataRefImpl &Rel) const {
1176   Rel.d.b++;
1177 }
1178 
1179 uint64_t WasmObjectFile::getRelocationOffset(DataRefImpl Ref) const {
1180   const wasm::WasmRelocation &Rel = getWasmRelocation(Ref);
1181   return Rel.Offset;
1182 }
1183 
1184 symbol_iterator WasmObjectFile::getRelocationSymbol(DataRefImpl Ref) const {
1185   const wasm::WasmRelocation &Rel = getWasmRelocation(Ref);
1186   if (Rel.Type == wasm::R_WEBASSEMBLY_TYPE_INDEX_LEB)
1187     return symbol_end();
1188   DataRefImpl Sym;
1189   Sym.d.a = Rel.Index;
1190   Sym.d.b = 0;
1191   return symbol_iterator(SymbolRef(Sym, this));
1192 }
1193 
1194 uint64_t WasmObjectFile::getRelocationType(DataRefImpl Ref) const {
1195   const wasm::WasmRelocation &Rel = getWasmRelocation(Ref);
1196   return Rel.Type;
1197 }
1198 
1199 void WasmObjectFile::getRelocationTypeName(
1200     DataRefImpl Ref, SmallVectorImpl<char> &Result) const {
1201   const wasm::WasmRelocation& Rel = getWasmRelocation(Ref);
1202   StringRef Res = "Unknown";
1203 
1204 #define WASM_RELOC(name, value)  \
1205   case wasm::name:              \
1206     Res = #name;               \
1207     break;
1208 
1209   switch (Rel.Type) {
1210 #include "llvm/BinaryFormat/WasmRelocs.def"
1211   }
1212 
1213 #undef WASM_RELOC
1214 
1215   Result.append(Res.begin(), Res.end());
1216 }
1217 
1218 section_iterator WasmObjectFile::section_begin() const {
1219   DataRefImpl Ref;
1220   Ref.d.a = 0;
1221   return section_iterator(SectionRef(Ref, this));
1222 }
1223 
1224 section_iterator WasmObjectFile::section_end() const {
1225   DataRefImpl Ref;
1226   Ref.d.a = Sections.size();
1227   return section_iterator(SectionRef(Ref, this));
1228 }
1229 
1230 uint8_t WasmObjectFile::getBytesInAddress() const { return 4; }
1231 
1232 StringRef WasmObjectFile::getFileFormatName() const { return "WASM"; }
1233 
1234 Triple::ArchType WasmObjectFile::getArch() const { return Triple::wasm32; }
1235 
1236 SubtargetFeatures WasmObjectFile::getFeatures() const {
1237   return SubtargetFeatures();
1238 }
1239 
1240 bool WasmObjectFile::isRelocatableObject() const {
1241   return HasLinkingSection;
1242 }
1243 
1244 const WasmSection &WasmObjectFile::getWasmSection(DataRefImpl Ref) const {
1245   assert(Ref.d.a < Sections.size());
1246   return Sections[Ref.d.a];
1247 }
1248 
1249 const WasmSection &
1250 WasmObjectFile::getWasmSection(const SectionRef &Section) const {
1251   return getWasmSection(Section.getRawDataRefImpl());
1252 }
1253 
1254 const wasm::WasmRelocation &
1255 WasmObjectFile::getWasmRelocation(const RelocationRef &Ref) const {
1256   return getWasmRelocation(Ref.getRawDataRefImpl());
1257 }
1258 
1259 const wasm::WasmRelocation &
1260 WasmObjectFile::getWasmRelocation(DataRefImpl Ref) const {
1261   assert(Ref.d.a < Sections.size());
1262   const WasmSection& Sec = Sections[Ref.d.a];
1263   assert(Ref.d.b < Sec.Relocations.size());
1264   return Sec.Relocations[Ref.d.b];
1265 }
1266