xref: /llvm-project/llvm/lib/Object/WasmObjectFile.cpp (revision 6bb5a41f99445a9c067a699028d0d62a89953d12) 
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     default:
469       return make_error<GenericBinaryError>("Invalid symbol type",
470                                             object_error::parse_failed);
471     }
472 
473     if ((Info.Flags & wasm::WASM_SYMBOL_BINDING_MASK) !=
474             wasm::WASM_SYMBOL_BINDING_LOCAL &&
475         !SymbolNames.insert(Info.Name).second)
476       return make_error<GenericBinaryError>("Duplicate symbol name " +
477                                                 Twine(Info.Name),
478                                             object_error::parse_failed);
479     LinkingData.SymbolTable.emplace_back(Info);
480     Symbols.emplace_back(LinkingData.SymbolTable.back(), FunctionType,
481                          GlobalType);
482     DEBUG(dbgs() << "Adding symbol: " << Symbols.back() << "\n");
483   }
484 
485   return Error::success();
486 }
487 
488 Error WasmObjectFile::parseLinkingSectionComdat(const uint8_t *&Ptr,
489                                                 const uint8_t *End)
490 {
491   uint32_t ComdatCount = readVaruint32(Ptr);
492   StringSet<> ComdatSet;
493   for (unsigned ComdatIndex = 0; ComdatIndex < ComdatCount; ++ComdatIndex) {
494     StringRef Name = readString(Ptr);
495     if (Name.empty() || !ComdatSet.insert(Name).second)
496       return make_error<GenericBinaryError>("Bad/duplicate COMDAT name " + Twine(Name),
497                                             object_error::parse_failed);
498     LinkingData.Comdats.emplace_back(Name);
499     uint32_t Flags = readVaruint32(Ptr);
500     if (Flags != 0)
501       return make_error<GenericBinaryError>("Unsupported COMDAT flags",
502                                             object_error::parse_failed);
503 
504     uint32_t EntryCount = readVaruint32(Ptr);
505     while (EntryCount--) {
506       unsigned Kind = readVaruint32(Ptr);
507       unsigned Index = readVaruint32(Ptr);
508       switch (Kind) {
509       default:
510         return make_error<GenericBinaryError>("Invalid COMDAT entry type",
511                                               object_error::parse_failed);
512       case wasm::WASM_COMDAT_DATA:
513         if (Index >= DataSegments.size())
514           return make_error<GenericBinaryError>("COMDAT data index out of range",
515                                                 object_error::parse_failed);
516         if (DataSegments[Index].Data.Comdat != UINT32_MAX)
517           return make_error<GenericBinaryError>("Data segment in two COMDATs",
518                                                 object_error::parse_failed);
519         DataSegments[Index].Data.Comdat = ComdatIndex;
520         break;
521       case wasm::WASM_COMDAT_FUNCTION:
522         if (!isDefinedFunctionIndex(Index))
523           return make_error<GenericBinaryError>("COMDAT function index out of range",
524                                                 object_error::parse_failed);
525         if (getDefinedFunction(Index).Comdat != UINT32_MAX)
526           return make_error<GenericBinaryError>("Function in two COMDATs",
527                                                 object_error::parse_failed);
528         getDefinedFunction(Index).Comdat = ComdatIndex;
529         break;
530       }
531     }
532   }
533   return Error::success();
534 }
535 
536 Error WasmObjectFile::parseRelocSection(StringRef Name, const uint8_t *Ptr,
537                                         const uint8_t *End) {
538   uint32_t SectionIndex = readVaruint32(Ptr);
539   if (SectionIndex >= Sections.size())
540     return make_error<GenericBinaryError>("Invalid section index",
541                                           object_error::parse_failed);
542   WasmSection& Section = Sections[SectionIndex];
543   uint32_t RelocCount = readVaruint32(Ptr);
544   uint32_t EndOffset = Section.Content.size();
545   while (RelocCount--) {
546     wasm::WasmRelocation Reloc = {};
547     Reloc.Type = readVaruint32(Ptr);
548     Reloc.Offset = readVaruint32(Ptr);
549     Reloc.Index = readVaruint32(Ptr);
550     switch (Reloc.Type) {
551     case wasm::R_WEBASSEMBLY_FUNCTION_INDEX_LEB:
552     case wasm::R_WEBASSEMBLY_TABLE_INDEX_SLEB:
553     case wasm::R_WEBASSEMBLY_TABLE_INDEX_I32:
554       if (!isValidFunctionSymbol(Reloc.Index))
555         return make_error<GenericBinaryError>("Bad relocation function index",
556                                               object_error::parse_failed);
557       break;
558     case wasm::R_WEBASSEMBLY_TYPE_INDEX_LEB:
559       if (Reloc.Index >= Signatures.size())
560         return make_error<GenericBinaryError>("Bad relocation type index",
561                                               object_error::parse_failed);
562       break;
563     case wasm::R_WEBASSEMBLY_GLOBAL_INDEX_LEB:
564       if (!isValidGlobalSymbol(Reloc.Index))
565         return make_error<GenericBinaryError>("Bad relocation global index",
566                                               object_error::parse_failed);
567       break;
568     case wasm::R_WEBASSEMBLY_MEMORY_ADDR_LEB:
569     case wasm::R_WEBASSEMBLY_MEMORY_ADDR_SLEB:
570     case wasm::R_WEBASSEMBLY_MEMORY_ADDR_I32:
571       if (!isValidDataSymbol(Reloc.Index))
572         return make_error<GenericBinaryError>("Bad relocation data index",
573                                               object_error::parse_failed);
574       Reloc.Addend = readVarint32(Ptr);
575       break;
576     default:
577       return make_error<GenericBinaryError>("Bad relocation type: " +
578                                                 Twine(Reloc.Type),
579                                             object_error::parse_failed);
580     }
581 
582     // Relocations must fit inside the section, and must appear in order.  They
583     // also shouldn't overlap a function/element boundary, but we don't bother
584     // to check that.
585     uint64_t Size = 5;
586     if (Reloc.Type == wasm::R_WEBASSEMBLY_TABLE_INDEX_I32 ||
587         Reloc.Type == wasm::R_WEBASSEMBLY_MEMORY_ADDR_I32)
588       Size = 4;
589     if (Reloc.Offset + Size > EndOffset)
590       return make_error<GenericBinaryError>("Bad relocation offset",
591                                             object_error::parse_failed);
592 
593     Section.Relocations.push_back(Reloc);
594   }
595   if (Ptr != End)
596     return make_error<GenericBinaryError>("Reloc section ended prematurely",
597                                           object_error::parse_failed);
598   return Error::success();
599 }
600 
601 Error WasmObjectFile::parseCustomSection(WasmSection &Sec,
602                                          const uint8_t *Ptr, const uint8_t *End) {
603   if (Sec.Name == "name") {
604     if (Error Err = parseNameSection(Ptr, End))
605       return Err;
606   } else if (Sec.Name == "linking") {
607     if (Error Err = parseLinkingSection(Ptr, End))
608       return Err;
609   } else if (Sec.Name.startswith("reloc.")) {
610     if (Error Err = parseRelocSection(Sec.Name, Ptr, End))
611       return Err;
612   }
613   return Error::success();
614 }
615 
616 Error WasmObjectFile::parseTypeSection(const uint8_t *Ptr, const uint8_t *End) {
617   uint32_t Count = readVaruint32(Ptr);
618   Signatures.reserve(Count);
619   while (Count--) {
620     wasm::WasmSignature Sig;
621     Sig.ReturnType = wasm::WASM_TYPE_NORESULT;
622     uint8_t Form = readUint8(Ptr);
623     if (Form != wasm::WASM_TYPE_FUNC) {
624       return make_error<GenericBinaryError>("Invalid signature type",
625                                             object_error::parse_failed);
626     }
627     uint32_t ParamCount = readVaruint32(Ptr);
628     Sig.ParamTypes.reserve(ParamCount);
629     while (ParamCount--) {
630       uint32_t ParamType = readUint8(Ptr);
631       Sig.ParamTypes.push_back(ParamType);
632     }
633     uint32_t ReturnCount = readVaruint32(Ptr);
634     if (ReturnCount) {
635       if (ReturnCount != 1) {
636         return make_error<GenericBinaryError>(
637             "Multiple return types not supported", object_error::parse_failed);
638       }
639       Sig.ReturnType = readUint8(Ptr);
640     }
641     Signatures.push_back(Sig);
642   }
643   if (Ptr != End)
644     return make_error<GenericBinaryError>("Type section ended prematurely",
645                                           object_error::parse_failed);
646   return Error::success();
647 }
648 
649 Error WasmObjectFile::parseImportSection(const uint8_t *Ptr, const uint8_t *End) {
650   uint32_t Count = readVaruint32(Ptr);
651   Imports.reserve(Count);
652   for (uint32_t i = 0; i < Count; i++) {
653     wasm::WasmImport Im;
654     Im.Module = readString(Ptr);
655     Im.Field = readString(Ptr);
656     Im.Kind = readUint8(Ptr);
657     switch (Im.Kind) {
658     case wasm::WASM_EXTERNAL_FUNCTION:
659       NumImportedFunctions++;
660       Im.SigIndex = readVaruint32(Ptr);
661       break;
662     case wasm::WASM_EXTERNAL_GLOBAL:
663       NumImportedGlobals++;
664       Im.Global.Type = readUint8(Ptr);
665       Im.Global.Mutable = readVaruint1(Ptr);
666       break;
667     case wasm::WASM_EXTERNAL_MEMORY:
668       Im.Memory = readLimits(Ptr);
669       break;
670     case wasm::WASM_EXTERNAL_TABLE:
671       Im.Table = readTable(Ptr);
672       if (Im.Table.ElemType != wasm::WASM_TYPE_ANYFUNC)
673         return make_error<GenericBinaryError>("Invalid table element type",
674                                               object_error::parse_failed);
675       break;
676     default:
677       return make_error<GenericBinaryError>(
678           "Unexpected import kind", object_error::parse_failed);
679     }
680     Imports.push_back(Im);
681   }
682   if (Ptr != End)
683     return make_error<GenericBinaryError>("Import section ended prematurely",
684                                           object_error::parse_failed);
685   return Error::success();
686 }
687 
688 Error WasmObjectFile::parseFunctionSection(const uint8_t *Ptr, const uint8_t *End) {
689   uint32_t Count = readVaruint32(Ptr);
690   FunctionTypes.reserve(Count);
691   uint32_t NumTypes = Signatures.size();
692   while (Count--) {
693     uint32_t Type = readVaruint32(Ptr);
694     if (Type >= NumTypes)
695       return make_error<GenericBinaryError>("Invalid function type",
696                                             object_error::parse_failed);
697     FunctionTypes.push_back(Type);
698   }
699   if (Ptr != End)
700     return make_error<GenericBinaryError>("Function section ended prematurely",
701                                           object_error::parse_failed);
702   return Error::success();
703 }
704 
705 Error WasmObjectFile::parseTableSection(const uint8_t *Ptr, const uint8_t *End) {
706   uint32_t Count = readVaruint32(Ptr);
707   Tables.reserve(Count);
708   while (Count--) {
709     Tables.push_back(readTable(Ptr));
710     if (Tables.back().ElemType != wasm::WASM_TYPE_ANYFUNC) {
711       return make_error<GenericBinaryError>("Invalid table element type",
712                                             object_error::parse_failed);
713     }
714   }
715   if (Ptr != End)
716     return make_error<GenericBinaryError>("Table section ended prematurely",
717                                           object_error::parse_failed);
718   return Error::success();
719 }
720 
721 Error WasmObjectFile::parseMemorySection(const uint8_t *Ptr, const uint8_t *End) {
722   uint32_t Count = readVaruint32(Ptr);
723   Memories.reserve(Count);
724   while (Count--) {
725     Memories.push_back(readLimits(Ptr));
726   }
727   if (Ptr != End)
728     return make_error<GenericBinaryError>("Memory section ended prematurely",
729                                           object_error::parse_failed);
730   return Error::success();
731 }
732 
733 Error WasmObjectFile::parseGlobalSection(const uint8_t *Ptr, const uint8_t *End) {
734   GlobalSection = Sections.size();
735   uint32_t Count = readVaruint32(Ptr);
736   Globals.reserve(Count);
737   while (Count--) {
738     wasm::WasmGlobal Global;
739     Global.Index = NumImportedGlobals + Globals.size();
740     Global.Type.Type = readUint8(Ptr);
741     Global.Type.Mutable = readVaruint1(Ptr);
742     if (Error Err = readInitExpr(Global.InitExpr, Ptr))
743       return Err;
744     Globals.push_back(Global);
745   }
746   if (Ptr != End)
747     return make_error<GenericBinaryError>("Global section ended prematurely",
748                                           object_error::parse_failed);
749   return Error::success();
750 }
751 
752 Error WasmObjectFile::parseExportSection(const uint8_t *Ptr, const uint8_t *End) {
753   uint32_t Count = readVaruint32(Ptr);
754   Exports.reserve(Count);
755   for (uint32_t i = 0; i < Count; i++) {
756     wasm::WasmExport Ex;
757     Ex.Name = readString(Ptr);
758     Ex.Kind = readUint8(Ptr);
759     Ex.Index = readVaruint32(Ptr);
760     switch (Ex.Kind) {
761     case wasm::WASM_EXTERNAL_FUNCTION:
762       if (!isValidFunctionIndex(Ex.Index))
763         return make_error<GenericBinaryError>("Invalid function export",
764                                               object_error::parse_failed);
765       break;
766     case wasm::WASM_EXTERNAL_GLOBAL:
767       if (!isValidGlobalIndex(Ex.Index))
768         return make_error<GenericBinaryError>("Invalid global export",
769                                               object_error::parse_failed);
770       break;
771     case wasm::WASM_EXTERNAL_MEMORY:
772     case wasm::WASM_EXTERNAL_TABLE:
773       break;
774     default:
775       return make_error<GenericBinaryError>(
776           "Unexpected export kind", object_error::parse_failed);
777     }
778     Exports.push_back(Ex);
779   }
780   if (Ptr != End)
781     return make_error<GenericBinaryError>("Export section ended prematurely",
782                                           object_error::parse_failed);
783   return Error::success();
784 }
785 
786 bool WasmObjectFile::isValidFunctionIndex(uint32_t Index) const {
787   return Index < NumImportedFunctions + FunctionTypes.size();
788 }
789 
790 bool WasmObjectFile::isDefinedFunctionIndex(uint32_t Index) const {
791   return Index >= NumImportedFunctions && isValidFunctionIndex(Index);
792 }
793 
794 bool WasmObjectFile::isValidGlobalIndex(uint32_t Index) const {
795   return Index < NumImportedGlobals + Globals.size();
796 }
797 
798 bool WasmObjectFile::isDefinedGlobalIndex(uint32_t Index) const {
799   return Index >= NumImportedGlobals && isValidGlobalIndex(Index);
800 }
801 
802 bool WasmObjectFile::isValidFunctionSymbol(uint32_t Index) const {
803   return Index < Symbols.size() && Symbols[Index].isTypeFunction();
804 }
805 
806 bool WasmObjectFile::isValidGlobalSymbol(uint32_t Index) const {
807   return Index < Symbols.size() && Symbols[Index].isTypeGlobal();
808 }
809 
810 bool WasmObjectFile::isValidDataSymbol(uint32_t Index) const {
811   return Index < Symbols.size() && Symbols[Index].isTypeData();
812 }
813 
814 wasm::WasmFunction &WasmObjectFile::getDefinedFunction(uint32_t Index) {
815   assert(isDefinedFunctionIndex(Index));
816   return Functions[Index - NumImportedFunctions];
817 }
818 
819 wasm::WasmGlobal &WasmObjectFile::getDefinedGlobal(uint32_t Index) {
820   assert(isDefinedGlobalIndex(Index));
821   return Globals[Index - NumImportedGlobals];
822 }
823 
824 Error WasmObjectFile::parseStartSection(const uint8_t *Ptr, const uint8_t *End) {
825   StartFunction = readVaruint32(Ptr);
826   if (!isValidFunctionIndex(StartFunction))
827     return make_error<GenericBinaryError>("Invalid start function",
828                                           object_error::parse_failed);
829   return Error::success();
830 }
831 
832 Error WasmObjectFile::parseCodeSection(const uint8_t *Ptr, const uint8_t *End) {
833   CodeSection = Sections.size();
834   const uint8_t *CodeSectionStart = Ptr;
835   uint32_t FunctionCount = readVaruint32(Ptr);
836   if (FunctionCount != FunctionTypes.size()) {
837     return make_error<GenericBinaryError>("Invalid function count",
838                                           object_error::parse_failed);
839   }
840 
841   while (FunctionCount--) {
842     wasm::WasmFunction Function;
843     const uint8_t *FunctionStart = Ptr;
844     uint32_t Size = readVaruint32(Ptr);
845     const uint8_t *FunctionEnd = Ptr + Size;
846 
847     Function.Index = NumImportedFunctions + Functions.size();
848     Function.CodeSectionOffset = FunctionStart - CodeSectionStart;
849     Function.Size = FunctionEnd - FunctionStart;
850 
851     uint32_t NumLocalDecls = readVaruint32(Ptr);
852     Function.Locals.reserve(NumLocalDecls);
853     while (NumLocalDecls--) {
854       wasm::WasmLocalDecl Decl;
855       Decl.Count = readVaruint32(Ptr);
856       Decl.Type = readUint8(Ptr);
857       Function.Locals.push_back(Decl);
858     }
859 
860     uint32_t BodySize = FunctionEnd - Ptr;
861     Function.Body = ArrayRef<uint8_t>(Ptr, BodySize);
862     // This will be set later when reading in the linking metadata section.
863     Function.Comdat = UINT32_MAX;
864     Ptr += BodySize;
865     assert(Ptr == FunctionEnd);
866     Functions.push_back(Function);
867   }
868   if (Ptr != End)
869     return make_error<GenericBinaryError>("Code section ended prematurely",
870                                           object_error::parse_failed);
871   return Error::success();
872 }
873 
874 Error WasmObjectFile::parseElemSection(const uint8_t *Ptr, const uint8_t *End) {
875   uint32_t Count = readVaruint32(Ptr);
876   ElemSegments.reserve(Count);
877   while (Count--) {
878     wasm::WasmElemSegment Segment;
879     Segment.TableIndex = readVaruint32(Ptr);
880     if (Segment.TableIndex != 0) {
881       return make_error<GenericBinaryError>("Invalid TableIndex",
882                                             object_error::parse_failed);
883     }
884     if (Error Err = readInitExpr(Segment.Offset, Ptr))
885       return Err;
886     uint32_t NumElems = readVaruint32(Ptr);
887     while (NumElems--) {
888       Segment.Functions.push_back(readVaruint32(Ptr));
889     }
890     ElemSegments.push_back(Segment);
891   }
892   if (Ptr != End)
893     return make_error<GenericBinaryError>("Elem section ended prematurely",
894                                           object_error::parse_failed);
895   return Error::success();
896 }
897 
898 Error WasmObjectFile::parseDataSection(const uint8_t *Ptr, const uint8_t *End) {
899   DataSection = Sections.size();
900   const uint8_t *Start = Ptr;
901   uint32_t Count = readVaruint32(Ptr);
902   DataSegments.reserve(Count);
903   while (Count--) {
904     WasmSegment Segment;
905     Segment.Data.MemoryIndex = readVaruint32(Ptr);
906     if (Error Err = readInitExpr(Segment.Data.Offset, Ptr))
907       return Err;
908     uint32_t Size = readVaruint32(Ptr);
909     Segment.Data.Content = ArrayRef<uint8_t>(Ptr, Size);
910     // The rest of these Data fields are set later, when reading in the linking
911     // metadata section.
912     Segment.Data.Alignment = 0;
913     Segment.Data.Flags = 0;
914     Segment.Data.Comdat = UINT32_MAX;
915     Segment.SectionOffset = Ptr - Start;
916     Ptr += Size;
917     DataSegments.push_back(Segment);
918   }
919   if (Ptr != End)
920     return make_error<GenericBinaryError>("Data section ended prematurely",
921                                           object_error::parse_failed);
922   return Error::success();
923 }
924 
925 const uint8_t *WasmObjectFile::getPtr(size_t Offset) const {
926   return reinterpret_cast<const uint8_t *>(getData().substr(Offset, 1).data());
927 }
928 
929 const wasm::WasmObjectHeader &WasmObjectFile::getHeader() const {
930   return Header;
931 }
932 
933 void WasmObjectFile::moveSymbolNext(DataRefImpl &Symb) const { Symb.d.a++; }
934 
935 uint32_t WasmObjectFile::getSymbolFlags(DataRefImpl Symb) const {
936   uint32_t Result = SymbolRef::SF_None;
937   const WasmSymbol &Sym = getWasmSymbol(Symb);
938 
939   DEBUG(dbgs() << "getSymbolFlags: ptr=" << &Sym << " " << Sym << "\n");
940   if (Sym.isBindingWeak())
941     Result |= SymbolRef::SF_Weak;
942   if (!Sym.isBindingLocal())
943     Result |= SymbolRef::SF_Global;
944   if (Sym.isHidden())
945     Result |= SymbolRef::SF_Hidden;
946   if (!Sym.isDefined())
947     Result |= SymbolRef::SF_Undefined;
948   if (Sym.isTypeFunction())
949     Result |= SymbolRef::SF_Executable;
950   return Result;
951 }
952 
953 basic_symbol_iterator WasmObjectFile::symbol_begin() const {
954   DataRefImpl Ref;
955   Ref.d.a = 0;
956   return BasicSymbolRef(Ref, this);
957 }
958 
959 basic_symbol_iterator WasmObjectFile::symbol_end() const {
960   DataRefImpl Ref;
961   Ref.d.a = Symbols.size();
962   return BasicSymbolRef(Ref, this);
963 }
964 
965 const WasmSymbol &WasmObjectFile::getWasmSymbol(const DataRefImpl &Symb) const {
966   return Symbols[Symb.d.a];
967 }
968 
969 const WasmSymbol &WasmObjectFile::getWasmSymbol(const SymbolRef &Symb) const {
970   return getWasmSymbol(Symb.getRawDataRefImpl());
971 }
972 
973 Expected<StringRef> WasmObjectFile::getSymbolName(DataRefImpl Symb) const {
974   return getWasmSymbol(Symb).Info.Name;
975 }
976 
977 Expected<uint64_t> WasmObjectFile::getSymbolAddress(DataRefImpl Symb) const {
978   return getSymbolValue(Symb);
979 }
980 
981 uint64_t WasmObjectFile::getWasmSymbolValue(const WasmSymbol& Sym) const {
982   switch (Sym.Info.Kind) {
983   case wasm::WASM_SYMBOL_TYPE_FUNCTION:
984   case wasm::WASM_SYMBOL_TYPE_GLOBAL:
985     return Sym.Info.ElementIndex;
986   case wasm::WASM_SYMBOL_TYPE_DATA: {
987     // The value of a data symbol is the segment offset, plus the symbol
988     // offset within the segment.
989     uint32_t SegmentIndex = Sym.Info.DataRef.Segment;
990     const wasm::WasmDataSegment &Segment = DataSegments[SegmentIndex].Data;
991     assert(Segment.Offset.Opcode == wasm::WASM_OPCODE_I32_CONST);
992     return Segment.Offset.Value.Int32 + Sym.Info.DataRef.Offset;
993   }
994   }
995   llvm_unreachable("invalid symbol type");
996 }
997 
998 uint64_t WasmObjectFile::getSymbolValueImpl(DataRefImpl Symb) const {
999   return getWasmSymbolValue(getWasmSymbol(Symb));
1000 }
1001 
1002 uint32_t WasmObjectFile::getSymbolAlignment(DataRefImpl Symb) const {
1003   llvm_unreachable("not yet implemented");
1004   return 0;
1005 }
1006 
1007 uint64_t WasmObjectFile::getCommonSymbolSizeImpl(DataRefImpl Symb) const {
1008   llvm_unreachable("not yet implemented");
1009   return 0;
1010 }
1011 
1012 Expected<SymbolRef::Type>
1013 WasmObjectFile::getSymbolType(DataRefImpl Symb) const {
1014   const WasmSymbol &Sym = getWasmSymbol(Symb);
1015 
1016   switch (Sym.Info.Kind) {
1017   case wasm::WASM_SYMBOL_TYPE_FUNCTION:
1018     return SymbolRef::ST_Function;
1019   case wasm::WASM_SYMBOL_TYPE_GLOBAL:
1020     return SymbolRef::ST_Other;
1021   case wasm::WASM_SYMBOL_TYPE_DATA:
1022     return SymbolRef::ST_Data;
1023   }
1024 
1025   llvm_unreachable("Unknown WasmSymbol::SymbolType");
1026   return SymbolRef::ST_Other;
1027 }
1028 
1029 Expected<section_iterator>
1030 WasmObjectFile::getSymbolSection(DataRefImpl Symb) const {
1031   const WasmSymbol& Sym = getWasmSymbol(Symb);
1032   if (Sym.isUndefined())
1033     return section_end();
1034 
1035   DataRefImpl Ref;
1036   switch (Sym.Info.Kind) {
1037   case wasm::WASM_SYMBOL_TYPE_FUNCTION:
1038     Ref.d.a = CodeSection;
1039     break;
1040   case wasm::WASM_SYMBOL_TYPE_GLOBAL:
1041     Ref.d.a = GlobalSection;
1042     break;
1043   case wasm::WASM_SYMBOL_TYPE_DATA:
1044     Ref.d.a = DataSection;
1045     break;
1046   default:
1047     llvm_unreachable("Unknown WasmSymbol::SymbolType");
1048   }
1049   return section_iterator(SectionRef(Ref, this));
1050 }
1051 
1052 void WasmObjectFile::moveSectionNext(DataRefImpl &Sec) const { Sec.d.a++; }
1053 
1054 std::error_code WasmObjectFile::getSectionName(DataRefImpl Sec,
1055                                                StringRef &Res) const {
1056   const WasmSection &S = Sections[Sec.d.a];
1057 #define ECase(X)                                                               \
1058   case wasm::WASM_SEC_##X:                                                     \
1059     Res = #X;                                                                  \
1060     break
1061   switch (S.Type) {
1062     ECase(TYPE);
1063     ECase(IMPORT);
1064     ECase(FUNCTION);
1065     ECase(TABLE);
1066     ECase(MEMORY);
1067     ECase(GLOBAL);
1068     ECase(EXPORT);
1069     ECase(START);
1070     ECase(ELEM);
1071     ECase(CODE);
1072     ECase(DATA);
1073   case wasm::WASM_SEC_CUSTOM:
1074     Res = S.Name;
1075     break;
1076   default:
1077     return object_error::invalid_section_index;
1078   }
1079 #undef ECase
1080   return std::error_code();
1081 }
1082 
1083 uint64_t WasmObjectFile::getSectionAddress(DataRefImpl Sec) const { return 0; }
1084 
1085 uint64_t WasmObjectFile::getSectionIndex(DataRefImpl Sec) const {
1086   return Sec.d.a;
1087 }
1088 
1089 uint64_t WasmObjectFile::getSectionSize(DataRefImpl Sec) const {
1090   const WasmSection &S = Sections[Sec.d.a];
1091   return S.Content.size();
1092 }
1093 
1094 std::error_code WasmObjectFile::getSectionContents(DataRefImpl Sec,
1095                                                    StringRef &Res) const {
1096   const WasmSection &S = Sections[Sec.d.a];
1097   // This will never fail since wasm sections can never be empty (user-sections
1098   // must have a name and non-user sections each have a defined structure).
1099   Res = StringRef(reinterpret_cast<const char *>(S.Content.data()),
1100                   S.Content.size());
1101   return std::error_code();
1102 }
1103 
1104 uint64_t WasmObjectFile::getSectionAlignment(DataRefImpl Sec) const {
1105   return 1;
1106 }
1107 
1108 bool WasmObjectFile::isSectionCompressed(DataRefImpl Sec) const {
1109   return false;
1110 }
1111 
1112 bool WasmObjectFile::isSectionText(DataRefImpl Sec) const {
1113   return getWasmSection(Sec).Type == wasm::WASM_SEC_CODE;
1114 }
1115 
1116 bool WasmObjectFile::isSectionData(DataRefImpl Sec) const {
1117   return getWasmSection(Sec).Type == wasm::WASM_SEC_DATA;
1118 }
1119 
1120 bool WasmObjectFile::isSectionBSS(DataRefImpl Sec) const { return false; }
1121 
1122 bool WasmObjectFile::isSectionVirtual(DataRefImpl Sec) const { return false; }
1123 
1124 bool WasmObjectFile::isSectionBitcode(DataRefImpl Sec) const { return false; }
1125 
1126 relocation_iterator WasmObjectFile::section_rel_begin(DataRefImpl Ref) const {
1127   DataRefImpl RelocRef;
1128   RelocRef.d.a = Ref.d.a;
1129   RelocRef.d.b = 0;
1130   return relocation_iterator(RelocationRef(RelocRef, this));
1131 }
1132 
1133 relocation_iterator WasmObjectFile::section_rel_end(DataRefImpl Ref) const {
1134   const WasmSection &Sec = getWasmSection(Ref);
1135   DataRefImpl RelocRef;
1136   RelocRef.d.a = Ref.d.a;
1137   RelocRef.d.b = Sec.Relocations.size();
1138   return relocation_iterator(RelocationRef(RelocRef, this));
1139 }
1140 
1141 void WasmObjectFile::moveRelocationNext(DataRefImpl &Rel) const {
1142   Rel.d.b++;
1143 }
1144 
1145 uint64_t WasmObjectFile::getRelocationOffset(DataRefImpl Ref) const {
1146   const wasm::WasmRelocation &Rel = getWasmRelocation(Ref);
1147   return Rel.Offset;
1148 }
1149 
1150 symbol_iterator WasmObjectFile::getRelocationSymbol(DataRefImpl Ref) const {
1151   const wasm::WasmRelocation &Rel = getWasmRelocation(Ref);
1152   if (Rel.Type == wasm::R_WEBASSEMBLY_TYPE_INDEX_LEB)
1153     return symbol_end();
1154   DataRefImpl Sym;
1155   Sym.d.a = Rel.Index;
1156   Sym.d.b = 0;
1157   return symbol_iterator(SymbolRef(Sym, this));
1158 }
1159 
1160 uint64_t WasmObjectFile::getRelocationType(DataRefImpl Ref) const {
1161   const wasm::WasmRelocation &Rel = getWasmRelocation(Ref);
1162   return Rel.Type;
1163 }
1164 
1165 void WasmObjectFile::getRelocationTypeName(
1166     DataRefImpl Ref, SmallVectorImpl<char> &Result) const {
1167   const wasm::WasmRelocation& Rel = getWasmRelocation(Ref);
1168   StringRef Res = "Unknown";
1169 
1170 #define WASM_RELOC(name, value)  \
1171   case wasm::name:              \
1172     Res = #name;               \
1173     break;
1174 
1175   switch (Rel.Type) {
1176 #include "llvm/BinaryFormat/WasmRelocs.def"
1177   }
1178 
1179 #undef WASM_RELOC
1180 
1181   Result.append(Res.begin(), Res.end());
1182 }
1183 
1184 section_iterator WasmObjectFile::section_begin() const {
1185   DataRefImpl Ref;
1186   Ref.d.a = 0;
1187   return section_iterator(SectionRef(Ref, this));
1188 }
1189 
1190 section_iterator WasmObjectFile::section_end() const {
1191   DataRefImpl Ref;
1192   Ref.d.a = Sections.size();
1193   return section_iterator(SectionRef(Ref, this));
1194 }
1195 
1196 uint8_t WasmObjectFile::getBytesInAddress() const { return 4; }
1197 
1198 StringRef WasmObjectFile::getFileFormatName() const { return "WASM"; }
1199 
1200 Triple::ArchType WasmObjectFile::getArch() const { return Triple::wasm32; }
1201 
1202 SubtargetFeatures WasmObjectFile::getFeatures() const {
1203   return SubtargetFeatures();
1204 }
1205 
1206 bool WasmObjectFile::isRelocatableObject() const {
1207   return HasLinkingSection;
1208 }
1209 
1210 const WasmSection &WasmObjectFile::getWasmSection(DataRefImpl Ref) const {
1211   assert(Ref.d.a < Sections.size());
1212   return Sections[Ref.d.a];
1213 }
1214 
1215 const WasmSection &
1216 WasmObjectFile::getWasmSection(const SectionRef &Section) const {
1217   return getWasmSection(Section.getRawDataRefImpl());
1218 }
1219 
1220 const wasm::WasmRelocation &
1221 WasmObjectFile::getWasmRelocation(const RelocationRef &Ref) const {
1222   return getWasmRelocation(Ref.getRawDataRefImpl());
1223 }
1224 
1225 const wasm::WasmRelocation &
1226 WasmObjectFile::getWasmRelocation(DataRefImpl Ref) const {
1227   assert(Ref.d.a < Sections.size());
1228   const WasmSection& Sec = Sections[Ref.d.a];
1229   assert(Ref.d.b < Sec.Relocations.size());
1230   return Sec.Relocations[Ref.d.b];
1231 }
1232