xref: /llvm-project/llvm/lib/Object/WasmObjectFile.cpp (revision f676cdd515d664e93ecbf8506af9610250195827) 
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   while (Ptr < End) {
317     uint8_t Type = readUint8(Ptr);
318     uint32_t Size = readVaruint32(Ptr);
319     const uint8_t *SubSectionEnd = Ptr + Size;
320     switch (Type) {
321     case wasm::WASM_SYMBOL_TABLE:
322       if (Error Err = parseLinkingSectionSymtab(Ptr, SubSectionEnd))
323         return Err;
324       break;
325     case wasm::WASM_SEGMENT_INFO: {
326       uint32_t Count = readVaruint32(Ptr);
327       if (Count > DataSegments.size())
328         return make_error<GenericBinaryError>("Too many segment names",
329                                               object_error::parse_failed);
330       for (uint32_t i = 0; i < Count; i++) {
331         DataSegments[i].Data.Name = readString(Ptr);
332         DataSegments[i].Data.Alignment = readVaruint32(Ptr);
333         DataSegments[i].Data.Flags = readVaruint32(Ptr);
334       }
335       break;
336     }
337     case wasm::WASM_INIT_FUNCS: {
338       uint32_t Count = readVaruint32(Ptr);
339       LinkingData.InitFunctions.reserve(Count);
340       for (uint32_t i = 0; i < Count; i++) {
341         wasm::WasmInitFunc Init;
342         Init.Priority = readVaruint32(Ptr);
343         Init.Symbol = readVaruint32(Ptr);
344         if (!isValidFunctionSymbol(Init.Symbol))
345           return make_error<GenericBinaryError>("Invalid function symbol: " +
346                                                     Twine(Init.Symbol),
347                                                 object_error::parse_failed);
348         LinkingData.InitFunctions.emplace_back(Init);
349       }
350       break;
351     }
352     case wasm::WASM_COMDAT_INFO:
353       if (Error Err = parseLinkingSectionComdat(Ptr, SubSectionEnd))
354         return Err;
355       break;
356     default:
357       Ptr += Size;
358       break;
359     }
360     if (Ptr != SubSectionEnd)
361       return make_error<GenericBinaryError>(
362           "Linking sub-section ended prematurely", object_error::parse_failed);
363   }
364   if (Ptr != End)
365     return make_error<GenericBinaryError>("Linking section ended prematurely",
366                                           object_error::parse_failed);
367   return Error::success();
368 }
369 
370 Error WasmObjectFile::parseLinkingSectionSymtab(const uint8_t *&Ptr,
371                                                 const uint8_t *End) {
372   uint32_t Count = readVaruint32(Ptr);
373   LinkingData.SymbolTable.reserve(Count);
374   Symbols.reserve(Count);
375   StringSet<> SymbolNames;
376 
377   std::vector<wasm::WasmImport *> ImportedGlobals;
378   std::vector<wasm::WasmImport *> ImportedFunctions;
379   ImportedGlobals.reserve(Imports.size());
380   ImportedFunctions.reserve(Imports.size());
381   for (auto &I : Imports) {
382     if (I.Kind == wasm::WASM_EXTERNAL_FUNCTION)
383       ImportedFunctions.emplace_back(&I);
384     else if (I.Kind == wasm::WASM_EXTERNAL_GLOBAL)
385       ImportedGlobals.emplace_back(&I);
386   }
387 
388   while (Count--) {
389     wasm::WasmSymbolInfo Info;
390     const wasm::WasmSignature *FunctionType = nullptr;
391     const wasm::WasmGlobalType *GlobalType = nullptr;
392 
393     Info.Kind = readUint8(Ptr);
394     Info.Flags = readVaruint32(Ptr);
395     bool IsDefined = (Info.Flags & wasm::WASM_SYMBOL_UNDEFINED) == 0;
396 
397     switch (Info.Kind) {
398     case wasm::WASM_SYMBOL_TYPE_FUNCTION:
399       Info.ElementIndex = readVaruint32(Ptr);
400       if (!isValidFunctionIndex(Info.ElementIndex) ||
401           IsDefined != isDefinedFunctionIndex(Info.ElementIndex))
402         return make_error<GenericBinaryError>("invalid function symbol index",
403                                               object_error::parse_failed);
404       if (IsDefined) {
405         Info.Name = readString(Ptr);
406         unsigned FuncIndex = Info.ElementIndex - NumImportedFunctions;
407         FunctionType = &Signatures[FunctionTypes[FuncIndex]];
408         wasm::WasmFunction &Function = Functions[FuncIndex];
409         if (Function.SymbolName.empty())
410           Function.SymbolName = Info.Name;
411       } else {
412         wasm::WasmImport &Import = *ImportedFunctions[Info.ElementIndex];
413         FunctionType = &Signatures[Import.SigIndex];
414         Info.Name = Import.Field;
415         Info.Module = Import.Module;
416       }
417       break;
418 
419     case wasm::WASM_SYMBOL_TYPE_GLOBAL:
420       Info.ElementIndex = readVaruint32(Ptr);
421       if (!isValidGlobalIndex(Info.ElementIndex) ||
422           IsDefined != isDefinedGlobalIndex(Info.ElementIndex))
423         return make_error<GenericBinaryError>("invalid global symbol index",
424                                               object_error::parse_failed);
425       if (!IsDefined &&
426           (Info.Flags & wasm::WASM_SYMBOL_BINDING_MASK) ==
427               wasm::WASM_SYMBOL_BINDING_WEAK)
428         return make_error<GenericBinaryError>("undefined weak global symbol",
429                                               object_error::parse_failed);
430       if (IsDefined) {
431         Info.Name = readString(Ptr);
432         unsigned GlobalIndex = Info.ElementIndex - NumImportedGlobals;
433         wasm::WasmGlobal &Global = Globals[GlobalIndex];
434         GlobalType = &Global.Type;
435         if (Global.SymbolName.empty())
436           Global.SymbolName = Info.Name;
437       } else {
438         wasm::WasmImport &Import = *ImportedGlobals[Info.ElementIndex];
439         Info.Name = Import.Field;
440         GlobalType = &Import.Global;
441       }
442       break;
443 
444     case wasm::WASM_SYMBOL_TYPE_DATA:
445       Info.Name = readString(Ptr);
446       if (IsDefined) {
447         uint32_t Index = readVaruint32(Ptr);
448         if (Index >= DataSegments.size())
449           return make_error<GenericBinaryError>("invalid data symbol index",
450                                                 object_error::parse_failed);
451         uint32_t Offset = readVaruint32(Ptr);
452         uint32_t Size = readVaruint32(Ptr);
453         if (Offset + Size > DataSegments[Index].Data.Content.size())
454           return make_error<GenericBinaryError>("invalid data symbol offset",
455                                                 object_error::parse_failed);
456         Info.DataRef = wasm::WasmDataReference{Index, Offset, Size};
457       }
458       break;
459 
460     default:
461       return make_error<GenericBinaryError>("Invalid symbol type",
462                                             object_error::parse_failed);
463     }
464 
465     if ((Info.Flags & wasm::WASM_SYMBOL_BINDING_MASK) !=
466             wasm::WASM_SYMBOL_BINDING_LOCAL &&
467         !SymbolNames.insert(Info.Name).second)
468       return make_error<GenericBinaryError>("Duplicate symbol name " +
469                                                 Twine(Info.Name),
470                                             object_error::parse_failed);
471     LinkingData.SymbolTable.emplace_back(Info);
472     Symbols.emplace_back(LinkingData.SymbolTable.back(), FunctionType,
473                          GlobalType);
474     DEBUG(dbgs() << "Adding symbol: " << Symbols.back() << "\n");
475   }
476 
477   return Error::success();
478 }
479 
480 Error WasmObjectFile::parseLinkingSectionComdat(const uint8_t *&Ptr,
481                                                 const uint8_t *End)
482 {
483   uint32_t ComdatCount = readVaruint32(Ptr);
484   StringSet<> ComdatSet;
485   for (unsigned ComdatIndex = 0; ComdatIndex < ComdatCount; ++ComdatIndex) {
486     StringRef Name = readString(Ptr);
487     if (Name.empty() || !ComdatSet.insert(Name).second)
488       return make_error<GenericBinaryError>("Bad/duplicate COMDAT name " + Twine(Name),
489                                             object_error::parse_failed);
490     LinkingData.Comdats.emplace_back(Name);
491     uint32_t Flags = readVaruint32(Ptr);
492     if (Flags != 0)
493       return make_error<GenericBinaryError>("Unsupported COMDAT flags",
494                                             object_error::parse_failed);
495 
496     uint32_t EntryCount = readVaruint32(Ptr);
497     while (EntryCount--) {
498       unsigned Kind = readVaruint32(Ptr);
499       unsigned Index = readVaruint32(Ptr);
500       switch (Kind) {
501       default:
502         return make_error<GenericBinaryError>("Invalid COMDAT entry type",
503                                               object_error::parse_failed);
504       case wasm::WASM_COMDAT_DATA:
505         if (Index >= DataSegments.size())
506           return make_error<GenericBinaryError>("COMDAT data index out of range",
507                                                 object_error::parse_failed);
508         if (DataSegments[Index].Data.Comdat != UINT32_MAX)
509           return make_error<GenericBinaryError>("Data segment in two COMDATs",
510                                                 object_error::parse_failed);
511         DataSegments[Index].Data.Comdat = ComdatIndex;
512         break;
513       case wasm::WASM_COMDAT_FUNCTION:
514         if (!isDefinedFunctionIndex(Index))
515           return make_error<GenericBinaryError>("COMDAT function index out of range",
516                                                 object_error::parse_failed);
517         if (getDefinedFunction(Index).Comdat != UINT32_MAX)
518           return make_error<GenericBinaryError>("Function in two COMDATs",
519                                                 object_error::parse_failed);
520         getDefinedFunction(Index).Comdat = ComdatIndex;
521         break;
522       }
523     }
524   }
525   return Error::success();
526 }
527 
528 Error WasmObjectFile::parseRelocSection(StringRef Name, const uint8_t *Ptr,
529                                         const uint8_t *End) {
530   uint32_t SectionIndex = readVaruint32(Ptr);
531   if (SectionIndex >= Sections.size())
532     return make_error<GenericBinaryError>("Invalid section index",
533                                           object_error::parse_failed);
534   WasmSection& Section = Sections[SectionIndex];
535   uint32_t RelocCount = readVaruint32(Ptr);
536   uint32_t EndOffset = Section.Content.size();
537   while (RelocCount--) {
538     wasm::WasmRelocation Reloc = {};
539     Reloc.Type = readVaruint32(Ptr);
540     Reloc.Offset = readVaruint32(Ptr);
541     Reloc.Index = readVaruint32(Ptr);
542     switch (Reloc.Type) {
543     case wasm::R_WEBASSEMBLY_FUNCTION_INDEX_LEB:
544     case wasm::R_WEBASSEMBLY_TABLE_INDEX_SLEB:
545     case wasm::R_WEBASSEMBLY_TABLE_INDEX_I32:
546       if (!isValidFunctionSymbol(Reloc.Index))
547         return make_error<GenericBinaryError>("Bad relocation function index",
548                                               object_error::parse_failed);
549       break;
550     case wasm::R_WEBASSEMBLY_TYPE_INDEX_LEB:
551       if (Reloc.Index >= Signatures.size())
552         return make_error<GenericBinaryError>("Bad relocation type index",
553                                               object_error::parse_failed);
554       break;
555     case wasm::R_WEBASSEMBLY_GLOBAL_INDEX_LEB:
556       if (!isValidGlobalSymbol(Reloc.Index))
557         return make_error<GenericBinaryError>("Bad relocation global index",
558                                               object_error::parse_failed);
559       break;
560     case wasm::R_WEBASSEMBLY_MEMORY_ADDR_LEB:
561     case wasm::R_WEBASSEMBLY_MEMORY_ADDR_SLEB:
562     case wasm::R_WEBASSEMBLY_MEMORY_ADDR_I32:
563       if (!isValidDataSymbol(Reloc.Index))
564         return make_error<GenericBinaryError>("Bad relocation data index",
565                                               object_error::parse_failed);
566       Reloc.Addend = readVarint32(Ptr);
567       break;
568     default:
569       return make_error<GenericBinaryError>("Bad relocation type: " +
570                                                 Twine(Reloc.Type),
571                                             object_error::parse_failed);
572     }
573 
574     // Relocations must fit inside the section, and must appear in order.  They
575     // also shouldn't overlap a function/element boundary, but we don't bother
576     // to check that.
577     uint64_t Size = 5;
578     if (Reloc.Type == wasm::R_WEBASSEMBLY_TABLE_INDEX_I32 ||
579         Reloc.Type == wasm::R_WEBASSEMBLY_MEMORY_ADDR_I32)
580       Size = 4;
581     if (Reloc.Offset + Size > EndOffset)
582       return make_error<GenericBinaryError>("Bad relocation offset",
583                                             object_error::parse_failed);
584 
585     Section.Relocations.push_back(Reloc);
586   }
587   if (Ptr != End)
588     return make_error<GenericBinaryError>("Reloc section ended prematurely",
589                                           object_error::parse_failed);
590   return Error::success();
591 }
592 
593 Error WasmObjectFile::parseCustomSection(WasmSection &Sec,
594                                          const uint8_t *Ptr, const uint8_t *End) {
595   if (Sec.Name == "name") {
596     if (Error Err = parseNameSection(Ptr, End))
597       return Err;
598   } else if (Sec.Name == "linking") {
599     if (Error Err = parseLinkingSection(Ptr, End))
600       return Err;
601   } else if (Sec.Name.startswith("reloc.")) {
602     if (Error Err = parseRelocSection(Sec.Name, Ptr, End))
603       return Err;
604   }
605   return Error::success();
606 }
607 
608 Error WasmObjectFile::parseTypeSection(const uint8_t *Ptr, const uint8_t *End) {
609   uint32_t Count = readVaruint32(Ptr);
610   Signatures.reserve(Count);
611   while (Count--) {
612     wasm::WasmSignature Sig;
613     Sig.ReturnType = wasm::WASM_TYPE_NORESULT;
614     uint8_t Form = readUint8(Ptr);
615     if (Form != wasm::WASM_TYPE_FUNC) {
616       return make_error<GenericBinaryError>("Invalid signature type",
617                                             object_error::parse_failed);
618     }
619     uint32_t ParamCount = readVaruint32(Ptr);
620     Sig.ParamTypes.reserve(ParamCount);
621     while (ParamCount--) {
622       uint32_t ParamType = readUint8(Ptr);
623       Sig.ParamTypes.push_back(ParamType);
624     }
625     uint32_t ReturnCount = readVaruint32(Ptr);
626     if (ReturnCount) {
627       if (ReturnCount != 1) {
628         return make_error<GenericBinaryError>(
629             "Multiple return types not supported", object_error::parse_failed);
630       }
631       Sig.ReturnType = readUint8(Ptr);
632     }
633     Signatures.push_back(Sig);
634   }
635   if (Ptr != End)
636     return make_error<GenericBinaryError>("Type section ended prematurely",
637                                           object_error::parse_failed);
638   return Error::success();
639 }
640 
641 Error WasmObjectFile::parseImportSection(const uint8_t *Ptr, const uint8_t *End) {
642   uint32_t Count = readVaruint32(Ptr);
643   Imports.reserve(Count);
644   for (uint32_t i = 0; i < Count; i++) {
645     wasm::WasmImport Im;
646     Im.Module = readString(Ptr);
647     Im.Field = readString(Ptr);
648     Im.Kind = readUint8(Ptr);
649     switch (Im.Kind) {
650     case wasm::WASM_EXTERNAL_FUNCTION:
651       NumImportedFunctions++;
652       Im.SigIndex = readVaruint32(Ptr);
653       break;
654     case wasm::WASM_EXTERNAL_GLOBAL:
655       NumImportedGlobals++;
656       Im.Global.Type = readUint8(Ptr);
657       Im.Global.Mutable = readVaruint1(Ptr);
658       break;
659     case wasm::WASM_EXTERNAL_MEMORY:
660       Im.Memory = readLimits(Ptr);
661       break;
662     case wasm::WASM_EXTERNAL_TABLE:
663       Im.Table = readTable(Ptr);
664       if (Im.Table.ElemType != wasm::WASM_TYPE_ANYFUNC)
665         return make_error<GenericBinaryError>("Invalid table element type",
666                                               object_error::parse_failed);
667       break;
668     default:
669       return make_error<GenericBinaryError>(
670           "Unexpected import kind", object_error::parse_failed);
671     }
672     Imports.push_back(Im);
673   }
674   if (Ptr != End)
675     return make_error<GenericBinaryError>("Import section ended prematurely",
676                                           object_error::parse_failed);
677   return Error::success();
678 }
679 
680 Error WasmObjectFile::parseFunctionSection(const uint8_t *Ptr, const uint8_t *End) {
681   uint32_t Count = readVaruint32(Ptr);
682   FunctionTypes.reserve(Count);
683   uint32_t NumTypes = Signatures.size();
684   while (Count--) {
685     uint32_t Type = readVaruint32(Ptr);
686     if (Type >= NumTypes)
687       return make_error<GenericBinaryError>("Invalid function type",
688                                             object_error::parse_failed);
689     FunctionTypes.push_back(Type);
690   }
691   if (Ptr != End)
692     return make_error<GenericBinaryError>("Function section ended prematurely",
693                                           object_error::parse_failed);
694   return Error::success();
695 }
696 
697 Error WasmObjectFile::parseTableSection(const uint8_t *Ptr, const uint8_t *End) {
698   uint32_t Count = readVaruint32(Ptr);
699   Tables.reserve(Count);
700   while (Count--) {
701     Tables.push_back(readTable(Ptr));
702     if (Tables.back().ElemType != wasm::WASM_TYPE_ANYFUNC) {
703       return make_error<GenericBinaryError>("Invalid table element type",
704                                             object_error::parse_failed);
705     }
706   }
707   if (Ptr != End)
708     return make_error<GenericBinaryError>("Table section ended prematurely",
709                                           object_error::parse_failed);
710   return Error::success();
711 }
712 
713 Error WasmObjectFile::parseMemorySection(const uint8_t *Ptr, const uint8_t *End) {
714   uint32_t Count = readVaruint32(Ptr);
715   Memories.reserve(Count);
716   while (Count--) {
717     Memories.push_back(readLimits(Ptr));
718   }
719   if (Ptr != End)
720     return make_error<GenericBinaryError>("Memory section ended prematurely",
721                                           object_error::parse_failed);
722   return Error::success();
723 }
724 
725 Error WasmObjectFile::parseGlobalSection(const uint8_t *Ptr, const uint8_t *End) {
726   GlobalSection = Sections.size();
727   uint32_t Count = readVaruint32(Ptr);
728   Globals.reserve(Count);
729   while (Count--) {
730     wasm::WasmGlobal Global;
731     Global.Index = NumImportedGlobals + Globals.size();
732     Global.Type.Type = readUint8(Ptr);
733     Global.Type.Mutable = readVaruint1(Ptr);
734     if (Error Err = readInitExpr(Global.InitExpr, Ptr))
735       return Err;
736     Globals.push_back(Global);
737   }
738   if (Ptr != End)
739     return make_error<GenericBinaryError>("Global section ended prematurely",
740                                           object_error::parse_failed);
741   return Error::success();
742 }
743 
744 Error WasmObjectFile::parseExportSection(const uint8_t *Ptr, const uint8_t *End) {
745   uint32_t Count = readVaruint32(Ptr);
746   Exports.reserve(Count);
747   for (uint32_t i = 0; i < Count; i++) {
748     wasm::WasmExport Ex;
749     Ex.Name = readString(Ptr);
750     Ex.Kind = readUint8(Ptr);
751     Ex.Index = readVaruint32(Ptr);
752     switch (Ex.Kind) {
753     case wasm::WASM_EXTERNAL_FUNCTION:
754       if (!isValidFunctionIndex(Ex.Index))
755         return make_error<GenericBinaryError>("Invalid function export",
756                                               object_error::parse_failed);
757       break;
758     case wasm::WASM_EXTERNAL_GLOBAL:
759       if (!isValidGlobalIndex(Ex.Index))
760         return make_error<GenericBinaryError>("Invalid global export",
761                                               object_error::parse_failed);
762       break;
763     case wasm::WASM_EXTERNAL_MEMORY:
764     case wasm::WASM_EXTERNAL_TABLE:
765       break;
766     default:
767       return make_error<GenericBinaryError>(
768           "Unexpected export kind", object_error::parse_failed);
769     }
770     Exports.push_back(Ex);
771   }
772   if (Ptr != End)
773     return make_error<GenericBinaryError>("Export section ended prematurely",
774                                           object_error::parse_failed);
775   return Error::success();
776 }
777 
778 bool WasmObjectFile::isValidFunctionIndex(uint32_t Index) const {
779   return Index < NumImportedFunctions + FunctionTypes.size();
780 }
781 
782 bool WasmObjectFile::isDefinedFunctionIndex(uint32_t Index) const {
783   return Index >= NumImportedFunctions && isValidFunctionIndex(Index);
784 }
785 
786 bool WasmObjectFile::isValidGlobalIndex(uint32_t Index) const {
787   return Index < NumImportedGlobals + Globals.size();
788 }
789 
790 bool WasmObjectFile::isDefinedGlobalIndex(uint32_t Index) const {
791   return Index >= NumImportedGlobals && isValidGlobalIndex(Index);
792 }
793 
794 bool WasmObjectFile::isValidFunctionSymbol(uint32_t Index) const {
795   return Index < Symbols.size() && Symbols[Index].isTypeFunction();
796 }
797 
798 bool WasmObjectFile::isValidGlobalSymbol(uint32_t Index) const {
799   return Index < Symbols.size() && Symbols[Index].isTypeGlobal();
800 }
801 
802 bool WasmObjectFile::isValidDataSymbol(uint32_t Index) const {
803   return Index < Symbols.size() && Symbols[Index].isTypeData();
804 }
805 
806 wasm::WasmFunction &WasmObjectFile::getDefinedFunction(uint32_t Index) {
807   assert(isDefinedFunctionIndex(Index));
808   return Functions[Index - NumImportedFunctions];
809 }
810 
811 wasm::WasmGlobal &WasmObjectFile::getDefinedGlobal(uint32_t Index) {
812   assert(isDefinedGlobalIndex(Index));
813   return Globals[Index - NumImportedGlobals];
814 }
815 
816 Error WasmObjectFile::parseStartSection(const uint8_t *Ptr, const uint8_t *End) {
817   StartFunction = readVaruint32(Ptr);
818   if (!isValidFunctionIndex(StartFunction))
819     return make_error<GenericBinaryError>("Invalid start function",
820                                           object_error::parse_failed);
821   return Error::success();
822 }
823 
824 Error WasmObjectFile::parseCodeSection(const uint8_t *Ptr, const uint8_t *End) {
825   CodeSection = Sections.size();
826   const uint8_t *CodeSectionStart = Ptr;
827   uint32_t FunctionCount = readVaruint32(Ptr);
828   if (FunctionCount != FunctionTypes.size()) {
829     return make_error<GenericBinaryError>("Invalid function count",
830                                           object_error::parse_failed);
831   }
832 
833   while (FunctionCount--) {
834     wasm::WasmFunction Function;
835     const uint8_t *FunctionStart = Ptr;
836     uint32_t Size = readVaruint32(Ptr);
837     const uint8_t *FunctionEnd = Ptr + Size;
838 
839     Function.Index = NumImportedFunctions + Functions.size();
840     Function.CodeSectionOffset = FunctionStart - CodeSectionStart;
841     Function.Size = FunctionEnd - FunctionStart;
842 
843     uint32_t NumLocalDecls = readVaruint32(Ptr);
844     Function.Locals.reserve(NumLocalDecls);
845     while (NumLocalDecls--) {
846       wasm::WasmLocalDecl Decl;
847       Decl.Count = readVaruint32(Ptr);
848       Decl.Type = readUint8(Ptr);
849       Function.Locals.push_back(Decl);
850     }
851 
852     uint32_t BodySize = FunctionEnd - Ptr;
853     Function.Body = ArrayRef<uint8_t>(Ptr, BodySize);
854     // This will be set later when reading in the linking metadata section.
855     Function.Comdat = UINT32_MAX;
856     Ptr += BodySize;
857     assert(Ptr == FunctionEnd);
858     Functions.push_back(Function);
859   }
860   if (Ptr != End)
861     return make_error<GenericBinaryError>("Code section ended prematurely",
862                                           object_error::parse_failed);
863   return Error::success();
864 }
865 
866 Error WasmObjectFile::parseElemSection(const uint8_t *Ptr, const uint8_t *End) {
867   uint32_t Count = readVaruint32(Ptr);
868   ElemSegments.reserve(Count);
869   while (Count--) {
870     wasm::WasmElemSegment Segment;
871     Segment.TableIndex = readVaruint32(Ptr);
872     if (Segment.TableIndex != 0) {
873       return make_error<GenericBinaryError>("Invalid TableIndex",
874                                             object_error::parse_failed);
875     }
876     if (Error Err = readInitExpr(Segment.Offset, Ptr))
877       return Err;
878     uint32_t NumElems = readVaruint32(Ptr);
879     while (NumElems--) {
880       Segment.Functions.push_back(readVaruint32(Ptr));
881     }
882     ElemSegments.push_back(Segment);
883   }
884   if (Ptr != End)
885     return make_error<GenericBinaryError>("Elem section ended prematurely",
886                                           object_error::parse_failed);
887   return Error::success();
888 }
889 
890 Error WasmObjectFile::parseDataSection(const uint8_t *Ptr, const uint8_t *End) {
891   DataSection = Sections.size();
892   const uint8_t *Start = Ptr;
893   uint32_t Count = readVaruint32(Ptr);
894   DataSegments.reserve(Count);
895   while (Count--) {
896     WasmSegment Segment;
897     Segment.Data.MemoryIndex = readVaruint32(Ptr);
898     if (Error Err = readInitExpr(Segment.Data.Offset, Ptr))
899       return Err;
900     uint32_t Size = readVaruint32(Ptr);
901     Segment.Data.Content = ArrayRef<uint8_t>(Ptr, Size);
902     // The rest of these Data fields are set later, when reading in the linking
903     // metadata section.
904     Segment.Data.Alignment = 0;
905     Segment.Data.Flags = 0;
906     Segment.Data.Comdat = UINT32_MAX;
907     Segment.SectionOffset = Ptr - Start;
908     Ptr += Size;
909     DataSegments.push_back(Segment);
910   }
911   if (Ptr != End)
912     return make_error<GenericBinaryError>("Data section ended prematurely",
913                                           object_error::parse_failed);
914   return Error::success();
915 }
916 
917 const uint8_t *WasmObjectFile::getPtr(size_t Offset) const {
918   return reinterpret_cast<const uint8_t *>(getData().substr(Offset, 1).data());
919 }
920 
921 const wasm::WasmObjectHeader &WasmObjectFile::getHeader() const {
922   return Header;
923 }
924 
925 void WasmObjectFile::moveSymbolNext(DataRefImpl &Symb) const { Symb.d.a++; }
926 
927 uint32_t WasmObjectFile::getSymbolFlags(DataRefImpl Symb) const {
928   uint32_t Result = SymbolRef::SF_None;
929   const WasmSymbol &Sym = getWasmSymbol(Symb);
930 
931   DEBUG(dbgs() << "getSymbolFlags: ptr=" << &Sym << " " << Sym << "\n");
932   if (Sym.isBindingWeak())
933     Result |= SymbolRef::SF_Weak;
934   if (!Sym.isBindingLocal())
935     Result |= SymbolRef::SF_Global;
936   if (Sym.isHidden())
937     Result |= SymbolRef::SF_Hidden;
938   if (!Sym.isDefined())
939     Result |= SymbolRef::SF_Undefined;
940   if (Sym.isTypeFunction())
941     Result |= SymbolRef::SF_Executable;
942   return Result;
943 }
944 
945 basic_symbol_iterator WasmObjectFile::symbol_begin() const {
946   DataRefImpl Ref;
947   Ref.d.a = 0;
948   return BasicSymbolRef(Ref, this);
949 }
950 
951 basic_symbol_iterator WasmObjectFile::symbol_end() const {
952   DataRefImpl Ref;
953   Ref.d.a = Symbols.size();
954   return BasicSymbolRef(Ref, this);
955 }
956 
957 const WasmSymbol &WasmObjectFile::getWasmSymbol(const DataRefImpl &Symb) const {
958   return Symbols[Symb.d.a];
959 }
960 
961 const WasmSymbol &WasmObjectFile::getWasmSymbol(const SymbolRef &Symb) const {
962   return getWasmSymbol(Symb.getRawDataRefImpl());
963 }
964 
965 Expected<StringRef> WasmObjectFile::getSymbolName(DataRefImpl Symb) const {
966   return getWasmSymbol(Symb).Info.Name;
967 }
968 
969 Expected<uint64_t> WasmObjectFile::getSymbolAddress(DataRefImpl Symb) const {
970   return getSymbolValue(Symb);
971 }
972 
973 uint64_t WasmObjectFile::getWasmSymbolValue(const WasmSymbol& Sym) const {
974   switch (Sym.Info.Kind) {
975   case wasm::WASM_SYMBOL_TYPE_FUNCTION:
976   case wasm::WASM_SYMBOL_TYPE_GLOBAL:
977     return Sym.Info.ElementIndex;
978   case wasm::WASM_SYMBOL_TYPE_DATA: {
979     // The value of a data symbol is the segment offset, plus the symbol
980     // offset within the segment.
981     uint32_t SegmentIndex = Sym.Info.DataRef.Segment;
982     const wasm::WasmDataSegment &Segment = DataSegments[SegmentIndex].Data;
983     assert(Segment.Offset.Opcode == wasm::WASM_OPCODE_I32_CONST);
984     return Segment.Offset.Value.Int32 + Sym.Info.DataRef.Offset;
985   }
986   }
987   llvm_unreachable("invalid symbol type");
988 }
989 
990 uint64_t WasmObjectFile::getSymbolValueImpl(DataRefImpl Symb) const {
991   return getWasmSymbolValue(getWasmSymbol(Symb));
992 }
993 
994 uint32_t WasmObjectFile::getSymbolAlignment(DataRefImpl Symb) const {
995   llvm_unreachable("not yet implemented");
996   return 0;
997 }
998 
999 uint64_t WasmObjectFile::getCommonSymbolSizeImpl(DataRefImpl Symb) const {
1000   llvm_unreachable("not yet implemented");
1001   return 0;
1002 }
1003 
1004 Expected<SymbolRef::Type>
1005 WasmObjectFile::getSymbolType(DataRefImpl Symb) const {
1006   const WasmSymbol &Sym = getWasmSymbol(Symb);
1007 
1008   switch (Sym.Info.Kind) {
1009   case wasm::WASM_SYMBOL_TYPE_FUNCTION:
1010     return SymbolRef::ST_Function;
1011   case wasm::WASM_SYMBOL_TYPE_GLOBAL:
1012     return SymbolRef::ST_Other;
1013   case wasm::WASM_SYMBOL_TYPE_DATA:
1014     return SymbolRef::ST_Data;
1015   }
1016 
1017   llvm_unreachable("Unknown WasmSymbol::SymbolType");
1018   return SymbolRef::ST_Other;
1019 }
1020 
1021 Expected<section_iterator>
1022 WasmObjectFile::getSymbolSection(DataRefImpl Symb) const {
1023   const WasmSymbol& Sym = getWasmSymbol(Symb);
1024   if (Sym.isUndefined())
1025     return section_end();
1026 
1027   DataRefImpl Ref;
1028   switch (Sym.Info.Kind) {
1029   case wasm::WASM_SYMBOL_TYPE_FUNCTION:
1030     Ref.d.a = CodeSection;
1031     break;
1032   case wasm::WASM_SYMBOL_TYPE_GLOBAL:
1033     Ref.d.a = GlobalSection;
1034     break;
1035   case wasm::WASM_SYMBOL_TYPE_DATA:
1036     Ref.d.a = DataSection;
1037     break;
1038   default:
1039     llvm_unreachable("Unknown WasmSymbol::SymbolType");
1040   }
1041   return section_iterator(SectionRef(Ref, this));
1042 }
1043 
1044 void WasmObjectFile::moveSectionNext(DataRefImpl &Sec) const { Sec.d.a++; }
1045 
1046 std::error_code WasmObjectFile::getSectionName(DataRefImpl Sec,
1047                                                StringRef &Res) const {
1048   const WasmSection &S = Sections[Sec.d.a];
1049 #define ECase(X)                                                               \
1050   case wasm::WASM_SEC_##X:                                                     \
1051     Res = #X;                                                                  \
1052     break
1053   switch (S.Type) {
1054     ECase(TYPE);
1055     ECase(IMPORT);
1056     ECase(FUNCTION);
1057     ECase(TABLE);
1058     ECase(MEMORY);
1059     ECase(GLOBAL);
1060     ECase(EXPORT);
1061     ECase(START);
1062     ECase(ELEM);
1063     ECase(CODE);
1064     ECase(DATA);
1065   case wasm::WASM_SEC_CUSTOM:
1066     Res = S.Name;
1067     break;
1068   default:
1069     return object_error::invalid_section_index;
1070   }
1071 #undef ECase
1072   return std::error_code();
1073 }
1074 
1075 uint64_t WasmObjectFile::getSectionAddress(DataRefImpl Sec) const { return 0; }
1076 
1077 uint64_t WasmObjectFile::getSectionIndex(DataRefImpl Sec) const {
1078   return Sec.d.a;
1079 }
1080 
1081 uint64_t WasmObjectFile::getSectionSize(DataRefImpl Sec) const {
1082   const WasmSection &S = Sections[Sec.d.a];
1083   return S.Content.size();
1084 }
1085 
1086 std::error_code WasmObjectFile::getSectionContents(DataRefImpl Sec,
1087                                                    StringRef &Res) const {
1088   const WasmSection &S = Sections[Sec.d.a];
1089   // This will never fail since wasm sections can never be empty (user-sections
1090   // must have a name and non-user sections each have a defined structure).
1091   Res = StringRef(reinterpret_cast<const char *>(S.Content.data()),
1092                   S.Content.size());
1093   return std::error_code();
1094 }
1095 
1096 uint64_t WasmObjectFile::getSectionAlignment(DataRefImpl Sec) const {
1097   return 1;
1098 }
1099 
1100 bool WasmObjectFile::isSectionCompressed(DataRefImpl Sec) const {
1101   return false;
1102 }
1103 
1104 bool WasmObjectFile::isSectionText(DataRefImpl Sec) const {
1105   return getWasmSection(Sec).Type == wasm::WASM_SEC_CODE;
1106 }
1107 
1108 bool WasmObjectFile::isSectionData(DataRefImpl Sec) const {
1109   return getWasmSection(Sec).Type == wasm::WASM_SEC_DATA;
1110 }
1111 
1112 bool WasmObjectFile::isSectionBSS(DataRefImpl Sec) const { return false; }
1113 
1114 bool WasmObjectFile::isSectionVirtual(DataRefImpl Sec) const { return false; }
1115 
1116 bool WasmObjectFile::isSectionBitcode(DataRefImpl Sec) const { return false; }
1117 
1118 relocation_iterator WasmObjectFile::section_rel_begin(DataRefImpl Ref) const {
1119   DataRefImpl RelocRef;
1120   RelocRef.d.a = Ref.d.a;
1121   RelocRef.d.b = 0;
1122   return relocation_iterator(RelocationRef(RelocRef, this));
1123 }
1124 
1125 relocation_iterator WasmObjectFile::section_rel_end(DataRefImpl Ref) const {
1126   const WasmSection &Sec = getWasmSection(Ref);
1127   DataRefImpl RelocRef;
1128   RelocRef.d.a = Ref.d.a;
1129   RelocRef.d.b = Sec.Relocations.size();
1130   return relocation_iterator(RelocationRef(RelocRef, this));
1131 }
1132 
1133 void WasmObjectFile::moveRelocationNext(DataRefImpl &Rel) const {
1134   Rel.d.b++;
1135 }
1136 
1137 uint64_t WasmObjectFile::getRelocationOffset(DataRefImpl Ref) const {
1138   const wasm::WasmRelocation &Rel = getWasmRelocation(Ref);
1139   return Rel.Offset;
1140 }
1141 
1142 symbol_iterator WasmObjectFile::getRelocationSymbol(DataRefImpl Ref) const {
1143   const wasm::WasmRelocation &Rel = getWasmRelocation(Ref);
1144   if (Rel.Type == wasm::R_WEBASSEMBLY_TYPE_INDEX_LEB)
1145     return symbol_end();
1146   DataRefImpl Sym;
1147   Sym.d.a = Rel.Index;
1148   Sym.d.b = 0;
1149   return symbol_iterator(SymbolRef(Sym, this));
1150 }
1151 
1152 uint64_t WasmObjectFile::getRelocationType(DataRefImpl Ref) const {
1153   const wasm::WasmRelocation &Rel = getWasmRelocation(Ref);
1154   return Rel.Type;
1155 }
1156 
1157 void WasmObjectFile::getRelocationTypeName(
1158     DataRefImpl Ref, SmallVectorImpl<char> &Result) const {
1159   const wasm::WasmRelocation& Rel = getWasmRelocation(Ref);
1160   StringRef Res = "Unknown";
1161 
1162 #define WASM_RELOC(name, value)  \
1163   case wasm::name:              \
1164     Res = #name;               \
1165     break;
1166 
1167   switch (Rel.Type) {
1168 #include "llvm/BinaryFormat/WasmRelocs.def"
1169   }
1170 
1171 #undef WASM_RELOC
1172 
1173   Result.append(Res.begin(), Res.end());
1174 }
1175 
1176 section_iterator WasmObjectFile::section_begin() const {
1177   DataRefImpl Ref;
1178   Ref.d.a = 0;
1179   return section_iterator(SectionRef(Ref, this));
1180 }
1181 
1182 section_iterator WasmObjectFile::section_end() const {
1183   DataRefImpl Ref;
1184   Ref.d.a = Sections.size();
1185   return section_iterator(SectionRef(Ref, this));
1186 }
1187 
1188 uint8_t WasmObjectFile::getBytesInAddress() const { return 4; }
1189 
1190 StringRef WasmObjectFile::getFileFormatName() const { return "WASM"; }
1191 
1192 Triple::ArchType WasmObjectFile::getArch() const { return Triple::wasm32; }
1193 
1194 SubtargetFeatures WasmObjectFile::getFeatures() const {
1195   return SubtargetFeatures();
1196 }
1197 
1198 bool WasmObjectFile::isRelocatableObject() const {
1199   return HasLinkingSection;
1200 }
1201 
1202 const WasmSection &WasmObjectFile::getWasmSection(DataRefImpl Ref) const {
1203   assert(Ref.d.a < Sections.size());
1204   return Sections[Ref.d.a];
1205 }
1206 
1207 const WasmSection &
1208 WasmObjectFile::getWasmSection(const SectionRef &Section) const {
1209   return getWasmSection(Section.getRawDataRefImpl());
1210 }
1211 
1212 const wasm::WasmRelocation &
1213 WasmObjectFile::getWasmRelocation(const RelocationRef &Ref) const {
1214   return getWasmRelocation(Ref.getRawDataRefImpl());
1215 }
1216 
1217 const wasm::WasmRelocation &
1218 WasmObjectFile::getWasmRelocation(DataRefImpl Ref) const {
1219   assert(Ref.d.a < Sections.size());
1220   const WasmSection& Sec = Sections[Ref.d.a];
1221   assert(Ref.d.b < Sec.Relocations.size());
1222   return Sec.Relocations[Ref.d.b];
1223 }
1224