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/STLExtras.h"
12 #include "llvm/ADT/StringRef.h"
13 #include "llvm/ADT/Triple.h"
14 #include "llvm/MC/SubtargetFeature.h"
15 #include "llvm/Object/Binary.h"
16 #include "llvm/Object/Error.h"
17 #include "llvm/Object/ObjectFile.h"
18 #include "llvm/Object/SymbolicFile.h"
19 #include "llvm/Object/Wasm.h"
20 #include "llvm/Support/Endian.h"
21 #include "llvm/Support/Error.h"
22 #include "llvm/Support/ErrorHandling.h"
23 #include "llvm/Support/LEB128.h"
24 #include "llvm/Support/Wasm.h"
25 #include <algorithm>
26 #include <cassert>
27 #include <cstdint>
28 #include <cstring>
29 #include <system_error>
30 
31 using namespace llvm;
32 using namespace object;
33 
34 Expected<std::unique_ptr<WasmObjectFile>>
35 ObjectFile::createWasmObjectFile(MemoryBufferRef Buffer) {
36   Error Err = Error::success();
37   auto ObjectFile = llvm::make_unique<WasmObjectFile>(Buffer, Err);
38   if (Err)
39     return std::move(Err);
40 
41   return std::move(ObjectFile);
42 }
43 
44 #define VARINT7_MAX ((1<<7)-1)
45 #define VARINT7_MIN (-(1<<7))
46 #define VARUINT7_MAX (1<<7)
47 #define VARUINT1_MAX (1)
48 
49 static uint8_t readUint8(const uint8_t *&Ptr) { return *Ptr++; }
50 
51 static uint32_t readUint32(const uint8_t *&Ptr) {
52   uint32_t Result = support::endian::read32le(Ptr);
53   Ptr += sizeof(Result);
54   return Result;
55 }
56 
57 static int32_t readFloat32(const uint8_t *&Ptr) {
58   int32_t Result = 0;
59   memcpy(&Result, Ptr, sizeof(Result));
60   Ptr += sizeof(Result);
61   return Result;
62 }
63 
64 static int64_t readFloat64(const uint8_t *&Ptr) {
65   int64_t Result = 0;
66   memcpy(&Result, Ptr, sizeof(Result));
67   Ptr += sizeof(Result);
68   return Result;
69 }
70 
71 static uint64_t readULEB128(const uint8_t *&Ptr) {
72   unsigned Count;
73   uint64_t Result = decodeULEB128(Ptr, &Count);
74   Ptr += Count;
75   return Result;
76 }
77 
78 static StringRef readString(const uint8_t *&Ptr) {
79   uint32_t StringLen = readULEB128(Ptr);
80   StringRef Return = StringRef(reinterpret_cast<const char *>(Ptr), StringLen);
81   Ptr += StringLen;
82   return Return;
83 }
84 
85 static int64_t readLEB128(const uint8_t *&Ptr) {
86   unsigned Count;
87   uint64_t Result = decodeSLEB128(Ptr, &Count);
88   Ptr += Count;
89   return Result;
90 }
91 
92 static uint8_t readVaruint1(const uint8_t *&Ptr) {
93   int64_t result = readLEB128(Ptr);
94   assert(result <= VARUINT1_MAX && result >= 0);
95   return result;
96 }
97 
98 static int8_t readVarint7(const uint8_t *&Ptr) {
99   int64_t result = readLEB128(Ptr);
100   assert(result <= VARINT7_MAX && result >= VARINT7_MIN);
101   return result;
102 }
103 
104 static uint8_t readVaruint7(const uint8_t *&Ptr) {
105   uint64_t result = readULEB128(Ptr);
106   assert(result <= VARUINT7_MAX);
107   return result;
108 }
109 
110 static int32_t readVarint32(const uint8_t *&Ptr) {
111   int64_t result = readLEB128(Ptr);
112   assert(result <= INT32_MAX && result >= INT32_MIN);
113   return result;
114 }
115 
116 static uint32_t readVaruint32(const uint8_t *&Ptr) {
117   uint64_t result = readULEB128(Ptr);
118   assert(result <= UINT32_MAX);
119   return result;
120 }
121 
122 static int64_t readVarint64(const uint8_t *&Ptr) {
123   return readLEB128(Ptr);
124 }
125 
126 static uint8_t readOpcode(const uint8_t *&Ptr) {
127   return readUint8(Ptr);
128 }
129 
130 static Error readInitExpr(wasm::WasmInitExpr &Expr, const uint8_t *&Ptr) {
131   Expr.Opcode = readOpcode(Ptr);
132 
133   switch (Expr.Opcode) {
134   case wasm::WASM_OPCODE_I32_CONST:
135     Expr.Value.Int32 = readVarint32(Ptr);
136     break;
137   case wasm::WASM_OPCODE_I64_CONST:
138     Expr.Value.Int64 = readVarint64(Ptr);
139     break;
140   case wasm::WASM_OPCODE_F32_CONST:
141     Expr.Value.Float32 = readFloat32(Ptr);
142     break;
143   case wasm::WASM_OPCODE_F64_CONST:
144     Expr.Value.Float64 = readFloat64(Ptr);
145     break;
146   case wasm::WASM_OPCODE_GET_GLOBAL:
147     Expr.Value.Global = readUint32(Ptr);
148     break;
149   default:
150     return make_error<GenericBinaryError>("Invalid opcode in init_expr",
151                                           object_error::parse_failed);
152   }
153 
154   uint8_t EndOpcode = readOpcode(Ptr);
155   if (EndOpcode != wasm::WASM_OPCODE_END) {
156     return make_error<GenericBinaryError>("Invalid init_expr",
157                                           object_error::parse_failed);
158   }
159   return Error::success();
160 }
161 
162 static wasm::WasmLimits readLimits(const uint8_t *&Ptr) {
163   wasm::WasmLimits Result;
164   Result.Flags = readVaruint1(Ptr);
165   Result.Initial = readVaruint32(Ptr);
166   if (Result.Flags & wasm::WASM_LIMITS_FLAG_HAS_MAX)
167     Result.Maximum = readVaruint32(Ptr);
168   return Result;
169 }
170 
171 static Error readSection(WasmSection &Section, const uint8_t *&Ptr,
172                          const uint8_t *Start) {
173   // TODO(sbc): Avoid reading past EOF in the case of malformed files.
174   Section.Offset = Ptr - Start;
175   Section.Type = readVaruint7(Ptr);
176   uint32_t Size = readVaruint32(Ptr);
177   if (Size == 0)
178     return make_error<StringError>("Zero length section",
179                                    object_error::parse_failed);
180   Section.Content = ArrayRef<uint8_t>(Ptr, Size);
181   Ptr += Size;
182   return Error::success();
183 }
184 
185 WasmObjectFile::WasmObjectFile(MemoryBufferRef Buffer, Error &Err)
186     : ObjectFile(Binary::ID_Wasm, Buffer) {
187   ErrorAsOutParameter ErrAsOutParam(&Err);
188   Header.Magic = getData().substr(0, 4);
189   if (Header.Magic != StringRef("\0asm", 4)) {
190     Err = make_error<StringError>("Bad magic number",
191                                   object_error::parse_failed);
192     return;
193   }
194   const uint8_t *Ptr = getPtr(4);
195   Header.Version = readUint32(Ptr);
196   if (Header.Version != wasm::WasmVersion) {
197     Err = make_error<StringError>("Bad version number",
198                                   object_error::parse_failed);
199     return;
200   }
201 
202   const uint8_t *Eof = getPtr(getData().size());
203   WasmSection Sec;
204   while (Ptr < Eof) {
205     if ((Err = readSection(Sec, Ptr, getPtr(0))))
206       return;
207     if ((Err = parseSection(Sec)))
208       return;
209 
210     Sections.push_back(Sec);
211   }
212 }
213 
214 Error WasmObjectFile::parseSection(WasmSection &Sec) {
215   const uint8_t* Start = Sec.Content.data();
216   const uint8_t* End = Start + Sec.Content.size();
217   switch (Sec.Type) {
218   case wasm::WASM_SEC_CUSTOM:
219     return parseCustomSection(Sec, Start, End);
220   case wasm::WASM_SEC_TYPE:
221     return parseTypeSection(Start, End);
222   case wasm::WASM_SEC_IMPORT:
223     return parseImportSection(Start, End);
224   case wasm::WASM_SEC_FUNCTION:
225     return parseFunctionSection(Start, End);
226   case wasm::WASM_SEC_TABLE:
227     return parseTableSection(Start, End);
228   case wasm::WASM_SEC_MEMORY:
229     return parseMemorySection(Start, End);
230   case wasm::WASM_SEC_GLOBAL:
231     return parseGlobalSection(Start, End);
232   case wasm::WASM_SEC_EXPORT:
233     return parseExportSection(Start, End);
234   case wasm::WASM_SEC_START:
235     return parseStartSection(Start, End);
236   case wasm::WASM_SEC_ELEM:
237     return parseElemSection(Start, End);
238   case wasm::WASM_SEC_CODE:
239     return parseCodeSection(Start, End);
240   case wasm::WASM_SEC_DATA:
241     return parseDataSection(Start, End);
242   default:
243     return make_error<GenericBinaryError>("Bad section type",
244                                           object_error::parse_failed);
245   }
246 }
247 
248 Error WasmObjectFile::parseNameSection(const uint8_t *Ptr, const uint8_t *End) {
249   while (Ptr < End) {
250     uint8_t Type = readVarint7(Ptr);
251     uint32_t Size = readVaruint32(Ptr);
252     switch (Type) {
253     case wasm::WASM_NAMES_FUNCTION: {
254       uint32_t Count = readVaruint32(Ptr);
255       while (Count--) {
256         /*uint32_t Index =*/readVaruint32(Ptr);
257         StringRef Name = readString(Ptr);
258         if (!Name.empty())
259           Symbols.emplace_back(Name,
260                                WasmSymbol::SymbolType::DEBUG_FUNCTION_NAME);
261       }
262       break;
263     }
264     // Ignore local names for now
265     case wasm::WASM_NAMES_LOCAL:
266     default:
267       Ptr += Size;
268       break;
269     }
270   }
271 
272   if (Ptr != End)
273     return make_error<GenericBinaryError>("Name section ended prematurely",
274                                           object_error::parse_failed);
275   return Error::success();
276 }
277 
278 WasmSection* WasmObjectFile::findCustomSectionByName(StringRef Name) {
279   for (WasmSection& Section : Sections) {
280     if (Section.Type == wasm::WASM_SEC_CUSTOM && Section.Name == Name)
281       return &Section;
282   }
283   return nullptr;
284 }
285 
286 WasmSection* WasmObjectFile::findSectionByType(uint32_t Type) {
287   assert(Type != wasm::WASM_SEC_CUSTOM);
288   for (WasmSection& Section : Sections) {
289     if (Section.Type == Type)
290       return &Section;
291   }
292   return nullptr;
293 }
294 
295 Error WasmObjectFile::parseRelocSection(StringRef Name, const uint8_t *Ptr,
296                                         const uint8_t *End) {
297   uint8_t SectionCode = readVarint7(Ptr);
298   WasmSection* Section = nullptr;
299   if (SectionCode == wasm::WASM_SEC_CUSTOM) {
300     StringRef Name = readString(Ptr);
301     Section = findCustomSectionByName(Name);
302   } else {
303     Section = findSectionByType(SectionCode);
304   }
305   if (!Section)
306     return make_error<GenericBinaryError>("Invalid section code",
307                                           object_error::parse_failed);
308   uint32_t RelocCount = readVaruint32(Ptr);
309   while (RelocCount--) {
310     wasm::WasmRelocation Reloc;
311     memset(&Reloc, 0, sizeof(Reloc));
312     Reloc.Type = readVaruint32(Ptr);
313     Reloc.Offset = readVaruint32(Ptr);
314     Reloc.Index = readVaruint32(Ptr);
315     switch (Reloc.Type) {
316     case wasm::R_WEBASSEMBLY_FUNCTION_INDEX_LEB:
317     case wasm::R_WEBASSEMBLY_TABLE_INDEX_SLEB:
318     case wasm::R_WEBASSEMBLY_TABLE_INDEX_I32:
319       break;
320     case wasm::R_WEBASSEMBLY_GLOBAL_ADDR_LEB:
321     case wasm::R_WEBASSEMBLY_GLOBAL_ADDR_SLEB:
322     case wasm::R_WEBASSEMBLY_GLOBAL_ADDR_I32:
323       Reloc.Addend = readVaruint32(Ptr);
324       break;
325     default:
326       return make_error<GenericBinaryError>("Bad relocation type",
327                                             object_error::parse_failed);
328     }
329     Section->Relocations.push_back(Reloc);
330   }
331   if (Ptr != End)
332     return make_error<GenericBinaryError>("Reloc section ended prematurely",
333                                           object_error::parse_failed);
334   return Error::success();
335 }
336 
337 Error WasmObjectFile::parseCustomSection(WasmSection &Sec,
338                                          const uint8_t *Ptr, const uint8_t *End) {
339   Sec.Name = readString(Ptr);
340   if (Sec.Name == "name") {
341     if (Error Err = parseNameSection(Ptr, End))
342       return Err;
343   } else if (Sec.Name.startswith("reloc.")) {
344     if (Error Err = parseRelocSection(Sec.Name, Ptr, End))
345       return Err;
346   }
347   return Error::success();
348 }
349 
350 Error WasmObjectFile::parseTypeSection(const uint8_t *Ptr, const uint8_t *End) {
351   uint32_t Count = readVaruint32(Ptr);
352   Signatures.reserve(Count);
353   while (Count--) {
354     wasm::WasmSignature Sig;
355     Sig.ReturnType = wasm::WASM_TYPE_NORESULT;
356     int8_t Form = readVarint7(Ptr);
357     if (Form != wasm::WASM_TYPE_FUNC) {
358       return make_error<GenericBinaryError>("Invalid signature type",
359                                             object_error::parse_failed);
360     }
361     uint32_t ParamCount = readVaruint32(Ptr);
362     Sig.ParamTypes.reserve(ParamCount);
363     while (ParamCount--) {
364       uint32_t ParamType = readVarint7(Ptr);
365       Sig.ParamTypes.push_back(ParamType);
366     }
367     uint32_t ReturnCount = readVaruint32(Ptr);
368     if (ReturnCount) {
369       if (ReturnCount != 1) {
370         return make_error<GenericBinaryError>(
371             "Multiple return types not supported", object_error::parse_failed);
372       }
373       Sig.ReturnType = readVarint7(Ptr);
374     }
375     Signatures.push_back(Sig);
376   }
377   if (Ptr != End)
378     return make_error<GenericBinaryError>("Type section ended prematurely",
379                                           object_error::parse_failed);
380   return Error::success();
381 }
382 
383 Error WasmObjectFile::parseImportSection(const uint8_t *Ptr, const uint8_t *End) {
384   uint32_t Count = readVaruint32(Ptr);
385   Imports.reserve(Count);
386   while (Count--) {
387     wasm::WasmImport Im;
388     Im.Module = readString(Ptr);
389     Im.Field = readString(Ptr);
390     Im.Kind = readUint8(Ptr);
391     switch (Im.Kind) {
392     case wasm::WASM_EXTERNAL_FUNCTION:
393       Im.SigIndex = readVaruint32(Ptr);
394       Symbols.emplace_back(Im.Field, WasmSymbol::SymbolType::FUNCTION_IMPORT);
395       break;
396     case wasm::WASM_EXTERNAL_GLOBAL:
397       Im.GlobalType = readVarint7(Ptr);
398       Im.GlobalMutable = readVaruint1(Ptr);
399       Symbols.emplace_back(Im.Field, WasmSymbol::SymbolType::GLOBAL_IMPORT);
400       break;
401     default:
402       // TODO(sbc): Handle other kinds of imports
403       return make_error<GenericBinaryError>(
404           "Unexpected import kind", object_error::parse_failed);
405     }
406     Imports.push_back(Im);
407   }
408   if (Ptr != End)
409     return make_error<GenericBinaryError>("Import section ended prematurely",
410                                           object_error::parse_failed);
411   return Error::success();
412 }
413 
414 Error WasmObjectFile::parseFunctionSection(const uint8_t *Ptr, const uint8_t *End) {
415   uint32_t Count = readVaruint32(Ptr);
416   FunctionTypes.reserve(Count);
417   while (Count--) {
418     FunctionTypes.push_back(readVaruint32(Ptr));
419   }
420   if (Ptr != End)
421     return make_error<GenericBinaryError>("Function section ended prematurely",
422                                           object_error::parse_failed);
423   return Error::success();
424 }
425 
426 Error WasmObjectFile::parseTableSection(const uint8_t *Ptr, const uint8_t *End) {
427   uint32_t Count = readVaruint32(Ptr);
428   Tables.reserve(Count);
429   while (Count--) {
430     wasm::WasmTable Table;
431     Table.ElemType = readVarint7(Ptr);
432     if (Table.ElemType != wasm::WASM_TYPE_ANYFUNC) {
433       return make_error<GenericBinaryError>("Invalid table element type",
434                                             object_error::parse_failed);
435     }
436     Table.Limits = readLimits(Ptr);
437     Tables.push_back(Table);
438   }
439   if (Ptr != End)
440     return make_error<GenericBinaryError>("Table section ended prematurely",
441                                           object_error::parse_failed);
442   return Error::success();
443 }
444 
445 Error WasmObjectFile::parseMemorySection(const uint8_t *Ptr, const uint8_t *End) {
446   uint32_t Count = readVaruint32(Ptr);
447   Memories.reserve(Count);
448   while (Count--) {
449     Memories.push_back(readLimits(Ptr));
450   }
451   if (Ptr != End)
452     return make_error<GenericBinaryError>("Memory section ended prematurely",
453                                           object_error::parse_failed);
454   return Error::success();
455 }
456 
457 Error WasmObjectFile::parseGlobalSection(const uint8_t *Ptr, const uint8_t *End) {
458   uint32_t Count = readVaruint32(Ptr);
459   Globals.reserve(Count);
460   while (Count--) {
461     wasm::WasmGlobal Global;
462     Global.Type = readVarint7(Ptr);
463     Global.Mutable = readVaruint1(Ptr);
464     if (Error Err = readInitExpr(Global.InitExpr, Ptr))
465       return Err;
466     Globals.push_back(Global);
467   }
468   if (Ptr != End)
469     return make_error<GenericBinaryError>("Global section ended prematurely",
470                                           object_error::parse_failed);
471   return Error::success();
472 }
473 
474 Error WasmObjectFile::parseExportSection(const uint8_t *Ptr, const uint8_t *End) {
475   uint32_t Count = readVaruint32(Ptr);
476   Exports.reserve(Count);
477   while (Count--) {
478     wasm::WasmExport Ex;
479     Ex.Name = readString(Ptr);
480     Ex.Kind = readUint8(Ptr);
481     Ex.Index = readVaruint32(Ptr);
482     Exports.push_back(Ex);
483     switch (Ex.Kind) {
484     case wasm::WASM_EXTERNAL_FUNCTION:
485       Symbols.emplace_back(Ex.Name, WasmSymbol::SymbolType::FUNCTION_EXPORT);
486       break;
487     case wasm::WASM_EXTERNAL_GLOBAL:
488       Symbols.emplace_back(Ex.Name, WasmSymbol::SymbolType::GLOBAL_EXPORT);
489       break;
490     default:
491       // TODO(sbc): Handle other kinds of exports
492       return make_error<GenericBinaryError>(
493           "Unexpected export kind", object_error::parse_failed);
494     }
495   }
496   if (Ptr != End)
497     return make_error<GenericBinaryError>("Export section ended prematurely",
498                                           object_error::parse_failed);
499   return Error::success();
500 }
501 
502 Error WasmObjectFile::parseStartSection(const uint8_t *Ptr, const uint8_t *End) {
503   StartFunction = readVaruint32(Ptr);
504   if (StartFunction < FunctionTypes.size())
505     return make_error<GenericBinaryError>("Invalid start function",
506                                           object_error::parse_failed);
507   return Error::success();
508 }
509 
510 Error WasmObjectFile::parseCodeSection(const uint8_t *Ptr, const uint8_t *End) {
511   uint32_t FunctionCount = readVaruint32(Ptr);
512   if (FunctionCount != FunctionTypes.size()) {
513     return make_error<GenericBinaryError>("Invalid function count",
514                                           object_error::parse_failed);
515   }
516 
517   CodeSection = ArrayRef<uint8_t>(Ptr, End - Ptr);
518 
519   while (FunctionCount--) {
520     wasm::WasmFunction Function;
521     uint32_t FunctionSize = readVaruint32(Ptr);
522     const uint8_t *FunctionEnd = Ptr + FunctionSize;
523 
524     uint32_t NumLocalDecls = readVaruint32(Ptr);
525     Function.Locals.reserve(NumLocalDecls);
526     while (NumLocalDecls--) {
527       wasm::WasmLocalDecl Decl;
528       Decl.Count = readVaruint32(Ptr);
529       Decl.Type = readVarint7(Ptr);
530       Function.Locals.push_back(Decl);
531     }
532 
533     uint32_t BodySize = FunctionEnd - Ptr;
534     Function.Body = ArrayRef<uint8_t>(Ptr, BodySize);
535     Ptr += BodySize;
536     assert(Ptr == FunctionEnd);
537     Functions.push_back(Function);
538   }
539   if (Ptr != End)
540     return make_error<GenericBinaryError>("Code section ended prematurely",
541                                           object_error::parse_failed);
542   return Error::success();
543 }
544 
545 Error WasmObjectFile::parseElemSection(const uint8_t *Ptr, const uint8_t *End) {
546   uint32_t Count = readVaruint32(Ptr);
547   ElemSegments.reserve(Count);
548   while (Count--) {
549     wasm::WasmElemSegment Segment;
550     Segment.TableIndex = readVaruint32(Ptr);
551     if (Segment.TableIndex != 0) {
552       return make_error<GenericBinaryError>("Invalid TableIndex",
553                                             object_error::parse_failed);
554     }
555     if (Error Err = readInitExpr(Segment.Offset, Ptr))
556       return Err;
557     uint32_t NumElems = readVaruint32(Ptr);
558     while (NumElems--) {
559       Segment.Functions.push_back(readVaruint32(Ptr));
560     }
561     ElemSegments.push_back(Segment);
562   }
563   if (Ptr != End)
564     return make_error<GenericBinaryError>("Elem section ended prematurely",
565                                           object_error::parse_failed);
566   return Error::success();
567 }
568 
569 Error WasmObjectFile::parseDataSection(const uint8_t *Ptr, const uint8_t *End) {
570   uint32_t Count = readVaruint32(Ptr);
571   DataSegments.reserve(Count);
572   while (Count--) {
573     wasm::WasmDataSegment Segment;
574     Segment.Index = readVaruint32(Ptr);
575     if (Error Err = readInitExpr(Segment.Offset, Ptr))
576       return Err;
577     uint32_t Size = readVaruint32(Ptr);
578     Segment.Content = ArrayRef<uint8_t>(Ptr, Size);
579     Ptr += Size;
580     DataSegments.push_back(Segment);
581   }
582   if (Ptr != End)
583     return make_error<GenericBinaryError>("Data section ended prematurely",
584                                           object_error::parse_failed);
585   return Error::success();
586 }
587 
588 const uint8_t *WasmObjectFile::getPtr(size_t Offset) const {
589   return reinterpret_cast<const uint8_t *>(getData().substr(Offset, 1).data());
590 }
591 
592 const wasm::WasmObjectHeader &WasmObjectFile::getHeader() const {
593   return Header;
594 }
595 
596 void WasmObjectFile::moveSymbolNext(DataRefImpl &Symb) const { Symb.d.a++; }
597 
598 uint32_t WasmObjectFile::getSymbolFlags(DataRefImpl Symb) const {
599   const WasmSymbol &Sym = getWasmSymbol(Symb);
600   switch (Sym.Type) {
601   case WasmSymbol::SymbolType::FUNCTION_IMPORT:
602     return object::SymbolRef::SF_Undefined | SymbolRef::SF_Executable;
603   case WasmSymbol::SymbolType::FUNCTION_EXPORT:
604     return object::SymbolRef::SF_Global | SymbolRef::SF_Executable;
605   case WasmSymbol::SymbolType::DEBUG_FUNCTION_NAME:
606     return object::SymbolRef::SF_Executable;
607   case WasmSymbol::SymbolType::GLOBAL_IMPORT:
608     return object::SymbolRef::SF_Undefined;
609   case WasmSymbol::SymbolType::GLOBAL_EXPORT:
610     return object::SymbolRef::SF_Global;
611   }
612   llvm_unreachable("Unknown WasmSymbol::SymbolType");
613 }
614 
615 basic_symbol_iterator WasmObjectFile::symbol_begin() const {
616   DataRefImpl Ref;
617   Ref.d.a = 0;
618   return BasicSymbolRef(Ref, this);
619 }
620 
621 basic_symbol_iterator WasmObjectFile::symbol_end() const {
622   DataRefImpl Ref;
623   Ref.d.a = Symbols.size();
624   return BasicSymbolRef(Ref, this);
625 }
626 
627 const WasmSymbol &WasmObjectFile::getWasmSymbol(DataRefImpl Symb) const {
628   return Symbols[Symb.d.a];
629 }
630 
631 Expected<StringRef> WasmObjectFile::getSymbolName(DataRefImpl Symb) const {
632   const WasmSymbol &Sym = getWasmSymbol(Symb);
633   return Sym.Name;
634 }
635 
636 Expected<uint64_t> WasmObjectFile::getSymbolAddress(DataRefImpl Symb) const {
637   return (uint64_t)Symb.d.a;
638 }
639 
640 uint64_t WasmObjectFile::getSymbolValueImpl(DataRefImpl Symb) const {
641   llvm_unreachable("not yet implemented");
642   return 0;
643 }
644 
645 uint32_t WasmObjectFile::getSymbolAlignment(DataRefImpl Symb) const {
646   llvm_unreachable("not yet implemented");
647   return 0;
648 }
649 
650 uint64_t WasmObjectFile::getCommonSymbolSizeImpl(DataRefImpl Symb) const {
651   llvm_unreachable("not yet implemented");
652   return 0;
653 }
654 
655 Expected<SymbolRef::Type>
656 WasmObjectFile::getSymbolType(DataRefImpl Symb) const {
657   llvm_unreachable("not yet implemented");
658   return errorCodeToError(object_error::invalid_symbol_index);
659 }
660 
661 Expected<section_iterator>
662 WasmObjectFile::getSymbolSection(DataRefImpl Symb) const {
663   llvm_unreachable("not yet implemented");
664   return errorCodeToError(object_error::invalid_symbol_index);
665 }
666 
667 void WasmObjectFile::moveSectionNext(DataRefImpl &Sec) const { Sec.d.a++; }
668 
669 std::error_code WasmObjectFile::getSectionName(DataRefImpl Sec,
670                                                StringRef &Res) const {
671   const WasmSection &S = Sections[Sec.d.a];
672 #define ECase(X)                                                               \
673   case wasm::WASM_SEC_##X:                                                     \
674     Res = #X;                                                                  \
675     break
676   switch (S.Type) {
677     ECase(TYPE);
678     ECase(IMPORT);
679     ECase(FUNCTION);
680     ECase(TABLE);
681     ECase(MEMORY);
682     ECase(GLOBAL);
683     ECase(EXPORT);
684     ECase(START);
685     ECase(ELEM);
686     ECase(CODE);
687     ECase(DATA);
688   case wasm::WASM_SEC_CUSTOM:
689     Res = S.Name;
690     break;
691   default:
692     return object_error::invalid_section_index;
693   }
694 #undef ECase
695   return std::error_code();
696 }
697 
698 uint64_t WasmObjectFile::getSectionAddress(DataRefImpl Sec) const { return 0; }
699 
700 uint64_t WasmObjectFile::getSectionSize(DataRefImpl Sec) const {
701   const WasmSection &S = Sections[Sec.d.a];
702   return S.Content.size();
703 }
704 
705 std::error_code WasmObjectFile::getSectionContents(DataRefImpl Sec,
706                                                    StringRef &Res) const {
707   const WasmSection &S = Sections[Sec.d.a];
708   // This will never fail since wasm sections can never be empty (user-sections
709   // must have a name and non-user sections each have a defined structure).
710   Res = StringRef(reinterpret_cast<const char *>(S.Content.data()),
711                   S.Content.size());
712   return std::error_code();
713 }
714 
715 uint64_t WasmObjectFile::getSectionAlignment(DataRefImpl Sec) const {
716   return 1;
717 }
718 
719 bool WasmObjectFile::isSectionCompressed(DataRefImpl Sec) const {
720   return false;
721 }
722 
723 bool WasmObjectFile::isSectionText(DataRefImpl Sec) const {
724   return getWasmSection(Sec).Type == wasm::WASM_SEC_CODE;
725 }
726 
727 bool WasmObjectFile::isSectionData(DataRefImpl Sec) const {
728   return getWasmSection(Sec).Type == wasm::WASM_SEC_DATA;
729 }
730 
731 bool WasmObjectFile::isSectionBSS(DataRefImpl Sec) const { return false; }
732 
733 bool WasmObjectFile::isSectionVirtual(DataRefImpl Sec) const { return false; }
734 
735 bool WasmObjectFile::isSectionBitcode(DataRefImpl Sec) const { return false; }
736 
737 relocation_iterator WasmObjectFile::section_rel_begin(DataRefImpl Ref) const {
738   DataRefImpl RelocRef;
739   RelocRef.d.a = Ref.d.a;
740   RelocRef.d.b = 0;
741   return relocation_iterator(RelocationRef(RelocRef, this));
742 }
743 
744 relocation_iterator WasmObjectFile::section_rel_end(DataRefImpl Ref) const {
745   const WasmSection &Sec = getWasmSection(Ref);
746   DataRefImpl RelocRef;
747   RelocRef.d.a = Ref.d.a;
748   RelocRef.d.b = Sec.Relocations.size();
749   return relocation_iterator(RelocationRef(RelocRef, this));
750 }
751 
752 void WasmObjectFile::moveRelocationNext(DataRefImpl &Rel) const {
753   Rel.d.b++;
754 }
755 
756 uint64_t WasmObjectFile::getRelocationOffset(DataRefImpl Ref) const {
757   const wasm::WasmRelocation &Rel = getWasmRelocation(Ref);
758   return Rel.Offset;
759 }
760 
761 symbol_iterator WasmObjectFile::getRelocationSymbol(DataRefImpl Rel) const {
762   llvm_unreachable("not yet implemented");
763   SymbolRef Ref;
764   return symbol_iterator(Ref);
765 }
766 
767 uint64_t WasmObjectFile::getRelocationType(DataRefImpl Ref) const {
768   const wasm::WasmRelocation &Rel = getWasmRelocation(Ref);
769   return Rel.Type;
770 }
771 
772 void WasmObjectFile::getRelocationTypeName(
773     DataRefImpl Ref, SmallVectorImpl<char> &Result) const {
774   const wasm::WasmRelocation& Rel = getWasmRelocation(Ref);
775   StringRef Res = "Unknown";
776 
777 #define WASM_RELOC(name, value)  \
778   case wasm::name:              \
779     Res = #name;               \
780     break;
781 
782   switch (Rel.Type) {
783 #include "llvm/Support/WasmRelocs/WebAssembly.def"
784   }
785 
786 #undef WASM_RELOC
787 
788   Result.append(Res.begin(), Res.end());
789 }
790 
791 section_iterator WasmObjectFile::section_begin() const {
792   DataRefImpl Ref;
793   Ref.d.a = 0;
794   return section_iterator(SectionRef(Ref, this));
795 }
796 
797 section_iterator WasmObjectFile::section_end() const {
798   DataRefImpl Ref;
799   Ref.d.a = Sections.size();
800   return section_iterator(SectionRef(Ref, this));
801 }
802 
803 uint8_t WasmObjectFile::getBytesInAddress() const { return 4; }
804 
805 StringRef WasmObjectFile::getFileFormatName() const { return "WASM"; }
806 
807 unsigned WasmObjectFile::getArch() const { return Triple::wasm32; }
808 
809 SubtargetFeatures WasmObjectFile::getFeatures() const {
810   return SubtargetFeatures();
811 }
812 
813 bool WasmObjectFile::isRelocatableObject() const { return false; }
814 
815 const WasmSection &WasmObjectFile::getWasmSection(DataRefImpl Ref) const {
816   assert(Ref.d.a < Sections.size());
817   return Sections[Ref.d.a];
818 }
819 
820 const WasmSection &
821 WasmObjectFile::getWasmSection(const SectionRef &Section) const {
822   return getWasmSection(Section.getRawDataRefImpl());
823 }
824 
825 const wasm::WasmRelocation &
826 WasmObjectFile::getWasmRelocation(const RelocationRef &Ref) const {
827   return getWasmRelocation(Ref.getRawDataRefImpl());
828 }
829 
830 const wasm::WasmRelocation &
831 WasmObjectFile::getWasmRelocation(DataRefImpl Ref) const {
832   assert(Ref.d.a < Sections.size());
833   const WasmSection& Sec = Sections[Ref.d.a];
834   assert(Ref.d.b < Sec.Relocations.size());
835   return Sec.Relocations[Ref.d.b];
836 }
837