WasmObjectFile.cpp revision 327952 
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/BinaryFormat/Wasm.h"
15#include "llvm/MC/SubtargetFeature.h"
16#include "llvm/Object/Binary.h"
17#include "llvm/Object/Error.h"
18#include "llvm/Object/ObjectFile.h"
19#include "llvm/Object/SymbolicFile.h"
20#include "llvm/Object/Wasm.h"
21#include "llvm/Support/Endian.h"
22#include "llvm/Support/Error.h"
23#include "llvm/Support/ErrorHandling.h"
24#include "llvm/Support/LEB128.h"
25#include <algorithm>
26#include <cassert>
27#include <cstdint>
28#include <cstring>
29#include <system_error>
30
31#define DEBUG_TYPE "wasm-object"
32
33using namespace llvm;
34using namespace object;
35
36Expected<std::unique_ptr<WasmObjectFile>>
37ObjectFile::createWasmObjectFile(MemoryBufferRef Buffer) {
38  Error Err = Error::success();
39  auto ObjectFile = llvm::make_unique<WasmObjectFile>(Buffer, Err);
40  if (Err)
41    return std::move(Err);
42
43  return std::move(ObjectFile);
44}
45
46#define VARINT7_MAX ((1<<7)-1)
47#define VARINT7_MIN (-(1<<7))
48#define VARUINT7_MAX (1<<7)
49#define VARUINT1_MAX (1)
50
51static uint8_t readUint8(const uint8_t *&Ptr) { return *Ptr++; }
52
53static uint32_t readUint32(const uint8_t *&Ptr) {
54  uint32_t Result = support::endian::read32le(Ptr);
55  Ptr += sizeof(Result);
56  return Result;
57}
58
59static int32_t readFloat32(const uint8_t *&Ptr) {
60  int32_t Result = 0;
61  memcpy(&Result, Ptr, sizeof(Result));
62  Ptr += sizeof(Result);
63  return Result;
64}
65
66static int64_t readFloat64(const uint8_t *&Ptr) {
67  int64_t Result = 0;
68  memcpy(&Result, Ptr, sizeof(Result));
69  Ptr += sizeof(Result);
70  return Result;
71}
72
73static uint64_t readULEB128(const uint8_t *&Ptr) {
74  unsigned Count;
75  uint64_t Result = decodeULEB128(Ptr, &Count);
76  Ptr += Count;
77  return Result;
78}
79
80static StringRef readString(const uint8_t *&Ptr) {
81  uint32_t StringLen = readULEB128(Ptr);
82  StringRef Return = StringRef(reinterpret_cast<const char *>(Ptr), StringLen);
83  Ptr += StringLen;
84  return Return;
85}
86
87static int64_t readLEB128(const uint8_t *&Ptr) {
88  unsigned Count;
89  uint64_t Result = decodeSLEB128(Ptr, &Count);
90  Ptr += Count;
91  return Result;
92}
93
94static uint8_t readVaruint1(const uint8_t *&Ptr) {
95  int64_t result = readLEB128(Ptr);
96  assert(result <= VARUINT1_MAX && result >= 0);
97  return result;
98}
99
100static int8_t readVarint7(const uint8_t *&Ptr) {
101  int64_t result = readLEB128(Ptr);
102  assert(result <= VARINT7_MAX && result >= VARINT7_MIN);
103  return result;
104}
105
106static uint8_t readVaruint7(const uint8_t *&Ptr) {
107  uint64_t result = readULEB128(Ptr);
108  assert(result <= VARUINT7_MAX);
109  return result;
110}
111
112static int32_t readVarint32(const uint8_t *&Ptr) {
113  int64_t result = readLEB128(Ptr);
114  assert(result <= INT32_MAX && result >= INT32_MIN);
115  return result;
116}
117
118static uint32_t readVaruint32(const uint8_t *&Ptr) {
119  uint64_t result = readULEB128(Ptr);
120  assert(result <= UINT32_MAX);
121  return result;
122}
123
124static int64_t readVarint64(const uint8_t *&Ptr) {
125  return readLEB128(Ptr);
126}
127
128static uint8_t readOpcode(const uint8_t *&Ptr) {
129  return readUint8(Ptr);
130}
131
132static Error readInitExpr(wasm::WasmInitExpr &Expr, const uint8_t *&Ptr) {
133  Expr.Opcode = readOpcode(Ptr);
134
135  switch (Expr.Opcode) {
136  case wasm::WASM_OPCODE_I32_CONST:
137    Expr.Value.Int32 = readVarint32(Ptr);
138    break;
139  case wasm::WASM_OPCODE_I64_CONST:
140    Expr.Value.Int64 = readVarint64(Ptr);
141    break;
142  case wasm::WASM_OPCODE_F32_CONST:
143    Expr.Value.Float32 = readFloat32(Ptr);
144    break;
145  case wasm::WASM_OPCODE_F64_CONST:
146    Expr.Value.Float64 = readFloat64(Ptr);
147    break;
148  case wasm::WASM_OPCODE_GET_GLOBAL:
149    Expr.Value.Global = readULEB128(Ptr);
150    break;
151  default:
152    return make_error<GenericBinaryError>("Invalid opcode in init_expr",
153                                          object_error::parse_failed);
154  }
155
156  uint8_t EndOpcode = readOpcode(Ptr);
157  if (EndOpcode != wasm::WASM_OPCODE_END) {
158    return make_error<GenericBinaryError>("Invalid init_expr",
159                                          object_error::parse_failed);
160  }
161  return Error::success();
162}
163
164static wasm::WasmLimits readLimits(const uint8_t *&Ptr) {
165  wasm::WasmLimits Result;
166  Result.Flags = readVaruint1(Ptr);
167  Result.Initial = readVaruint32(Ptr);
168  if (Result.Flags & wasm::WASM_LIMITS_FLAG_HAS_MAX)
169    Result.Maximum = readVaruint32(Ptr);
170  return Result;
171}
172
173static wasm::WasmTable readTable(const uint8_t *&Ptr) {
174  wasm::WasmTable Table;
175  Table.ElemType = readVarint7(Ptr);
176  Table.Limits = readLimits(Ptr);
177  return Table;
178}
179
180static Error readSection(WasmSection &Section, const uint8_t *&Ptr,
181                         const uint8_t *Start, const uint8_t *Eof) {
182  Section.Offset = Ptr - Start;
183  Section.Type = readVaruint7(Ptr);
184  uint32_t Size = readVaruint32(Ptr);
185  if (Size == 0)
186    return make_error<StringError>("Zero length section",
187                                   object_error::parse_failed);
188  if (Ptr + Size > Eof)
189    return make_error<StringError>("Section too large",
190                                   object_error::parse_failed);
191  Section.Content = ArrayRef<uint8_t>(Ptr, Size);
192  Ptr += Size;
193  return Error::success();
194}
195
196WasmObjectFile::WasmObjectFile(MemoryBufferRef Buffer, Error &Err)
197    : ObjectFile(Binary::ID_Wasm, Buffer) {
198  LinkingData.DataSize = 0;
199
200  ErrorAsOutParameter ErrAsOutParam(&Err);
201  Header.Magic = getData().substr(0, 4);
202  if (Header.Magic != StringRef("\0asm", 4)) {
203    Err = make_error<StringError>("Bad magic number",
204                                  object_error::parse_failed);
205    return;
206  }
207
208  const uint8_t *Eof = getPtr(getData().size());
209  const uint8_t *Ptr = getPtr(4);
210
211  if (Ptr + 4 > Eof) {
212    Err = make_error<StringError>("Missing version number",
213                                  object_error::parse_failed);
214    return;
215  }
216
217  Header.Version = readUint32(Ptr);
218  if (Header.Version != wasm::WasmVersion) {
219    Err = make_error<StringError>("Bad version number",
220                                  object_error::parse_failed);
221    return;
222  }
223
224  WasmSection Sec;
225  while (Ptr < Eof) {
226    if ((Err = readSection(Sec, Ptr, getPtr(0), Eof)))
227      return;
228    if ((Err = parseSection(Sec)))
229      return;
230
231    Sections.push_back(Sec);
232  }
233}
234
235Error WasmObjectFile::parseSection(WasmSection &Sec) {
236  const uint8_t* Start = Sec.Content.data();
237  const uint8_t* End = Start + Sec.Content.size();
238  switch (Sec.Type) {
239  case wasm::WASM_SEC_CUSTOM:
240    return parseCustomSection(Sec, Start, End);
241  case wasm::WASM_SEC_TYPE:
242    return parseTypeSection(Start, End);
243  case wasm::WASM_SEC_IMPORT:
244    return parseImportSection(Start, End);
245  case wasm::WASM_SEC_FUNCTION:
246    return parseFunctionSection(Start, End);
247  case wasm::WASM_SEC_TABLE:
248    return parseTableSection(Start, End);
249  case wasm::WASM_SEC_MEMORY:
250    return parseMemorySection(Start, End);
251  case wasm::WASM_SEC_GLOBAL:
252    return parseGlobalSection(Start, End);
253  case wasm::WASM_SEC_EXPORT:
254    return parseExportSection(Start, End);
255  case wasm::WASM_SEC_START:
256    return parseStartSection(Start, End);
257  case wasm::WASM_SEC_ELEM:
258    return parseElemSection(Start, End);
259  case wasm::WASM_SEC_CODE:
260    return parseCodeSection(Start, End);
261  case wasm::WASM_SEC_DATA:
262    return parseDataSection(Start, End);
263  default:
264    return make_error<GenericBinaryError>("Bad section type",
265                                          object_error::parse_failed);
266  }
267}
268
269Error WasmObjectFile::parseNameSection(const uint8_t *Ptr, const uint8_t *End) {
270  while (Ptr < End) {
271    uint8_t Type = readVarint7(Ptr);
272    uint32_t Size = readVaruint32(Ptr);
273    const uint8_t *SubSectionEnd = Ptr + Size;
274    switch (Type) {
275    case wasm::WASM_NAMES_FUNCTION: {
276      uint32_t Count = readVaruint32(Ptr);
277      while (Count--) {
278        uint32_t Index = readVaruint32(Ptr);
279        StringRef Name = readString(Ptr);
280        if (!Name.empty())
281          Symbols.emplace_back(Name,
282                               WasmSymbol::SymbolType::DEBUG_FUNCTION_NAME,
283                               Sections.size(), Index);
284      }
285      break;
286    }
287    // Ignore local names for now
288    case wasm::WASM_NAMES_LOCAL:
289    default:
290      Ptr += Size;
291      break;
292    }
293    if (Ptr != SubSectionEnd)
294      return make_error<GenericBinaryError>("Name sub-section ended prematurely",
295                                            object_error::parse_failed);
296  }
297
298  if (Ptr != End)
299    return make_error<GenericBinaryError>("Name section ended prematurely",
300                                          object_error::parse_failed);
301  return Error::success();
302}
303
304void WasmObjectFile::populateSymbolTable() {
305  // Add imports to symbol table
306  size_t GlobalIndex = 0;
307  size_t FunctionIndex = 0;
308  for (const wasm::WasmImport& Import : Imports) {
309    switch (Import.Kind) {
310    case wasm::WASM_EXTERNAL_GLOBAL:
311      assert(Import.Global.Type == wasm::WASM_TYPE_I32);
312      SymbolMap.try_emplace(Import.Field, Symbols.size());
313      Symbols.emplace_back(Import.Field, WasmSymbol::SymbolType::GLOBAL_IMPORT,
314                           ImportSection, GlobalIndex++);
315      DEBUG(dbgs() << "Adding import: " << Symbols.back()
316                   << " sym index:" << Symbols.size() << "\n");
317      break;
318    case wasm::WASM_EXTERNAL_FUNCTION:
319      SymbolMap.try_emplace(Import.Field, Symbols.size());
320      Symbols.emplace_back(Import.Field,
321                           WasmSymbol::SymbolType::FUNCTION_IMPORT,
322                           ImportSection, FunctionIndex++, Import.SigIndex);
323      DEBUG(dbgs() << "Adding import: " << Symbols.back()
324                   << " sym index:" << Symbols.size() << "\n");
325      break;
326    default:
327      break;
328    }
329  }
330
331  // Add exports to symbol table
332  for (const wasm::WasmExport& Export : Exports) {
333    if (Export.Kind == wasm::WASM_EXTERNAL_FUNCTION ||
334        Export.Kind == wasm::WASM_EXTERNAL_GLOBAL) {
335      WasmSymbol::SymbolType ExportType =
336          Export.Kind == wasm::WASM_EXTERNAL_FUNCTION
337              ? WasmSymbol::SymbolType::FUNCTION_EXPORT
338              : WasmSymbol::SymbolType::GLOBAL_EXPORT;
339      auto Pair = SymbolMap.try_emplace(Export.Name, Symbols.size());
340      if (Pair.second) {
341        Symbols.emplace_back(Export.Name, ExportType,
342                             ExportSection, Export.Index);
343        DEBUG(dbgs() << "Adding export: " << Symbols.back()
344                     << " sym index:" << Symbols.size() << "\n");
345      } else {
346        uint32_t SymIndex = Pair.first->second;
347        const WasmSymbol &OldSym = Symbols[SymIndex];
348        WasmSymbol NewSym(Export.Name, ExportType, ExportSection, Export.Index);
349        NewSym.setAltIndex(OldSym.ElementIndex);
350        Symbols[SymIndex] = NewSym;
351
352        DEBUG(dbgs() << "Replacing existing symbol:  " << NewSym
353                     << " sym index:" << SymIndex << "\n");
354      }
355    }
356  }
357}
358
359Error WasmObjectFile::parseLinkingSection(const uint8_t *Ptr,
360                                          const uint8_t *End) {
361  HasLinkingSection = true;
362
363  // Only populate the symbol table with imports and exports if the object
364  // has a linking section (i.e. its a relocatable object file). Otherwise
365  // the global might not represent symbols at all.
366  populateSymbolTable();
367
368  while (Ptr < End) {
369    uint8_t Type = readVarint7(Ptr);
370    uint32_t Size = readVaruint32(Ptr);
371    const uint8_t *SubSectionEnd = Ptr + Size;
372    switch (Type) {
373    case wasm::WASM_SYMBOL_INFO: {
374      uint32_t Count = readVaruint32(Ptr);
375      while (Count--) {
376        StringRef Symbol = readString(Ptr);
377        DEBUG(dbgs() << "reading syminfo: " << Symbol << "\n");
378        uint32_t Flags = readVaruint32(Ptr);
379        auto iter = SymbolMap.find(Symbol);
380        if (iter == SymbolMap.end()) {
381          return make_error<GenericBinaryError>(
382              "Invalid symbol name in linking section: " + Symbol,
383              object_error::parse_failed);
384        }
385        uint32_t SymIndex = iter->second;
386        assert(SymIndex < Symbols.size());
387        Symbols[SymIndex].Flags = Flags;
388        DEBUG(dbgs() << "Set symbol flags index:"
389                     << SymIndex << " name:"
390                     << Symbols[SymIndex].Name << " expected:"
391                     << Symbol << " flags: " << Flags << "\n");
392      }
393      break;
394    }
395    case wasm::WASM_DATA_SIZE:
396      LinkingData.DataSize = readVaruint32(Ptr);
397      break;
398    case wasm::WASM_SEGMENT_INFO: {
399      uint32_t Count = readVaruint32(Ptr);
400      if (Count > DataSegments.size())
401        return make_error<GenericBinaryError>("Too many segment names",
402                                              object_error::parse_failed);
403      for (uint32_t i = 0; i < Count; i++) {
404        DataSegments[i].Data.Name = readString(Ptr);
405        DataSegments[i].Data.Alignment = readVaruint32(Ptr);
406        DataSegments[i].Data.Flags = readVaruint32(Ptr);
407      }
408      break;
409    }
410    case wasm::WASM_INIT_FUNCS: {
411      uint32_t Count = readVaruint32(Ptr);
412      LinkingData.InitFunctions.reserve(Count);
413      for (uint32_t i = 0; i < Count; i++) {
414        wasm::WasmInitFunc Init;
415        Init.Priority = readVaruint32(Ptr);
416        Init.FunctionIndex = readVaruint32(Ptr);
417        if (!isValidFunctionIndex(Init.FunctionIndex))
418          return make_error<GenericBinaryError>("Invalid function index: " +
419                                                    Twine(Init.FunctionIndex),
420                                                object_error::parse_failed);
421        LinkingData.InitFunctions.emplace_back(Init);
422      }
423      break;
424    }
425    default:
426      Ptr += Size;
427      break;
428    }
429    if (Ptr != SubSectionEnd)
430      return make_error<GenericBinaryError>(
431          "Linking sub-section ended prematurely", object_error::parse_failed);
432  }
433  if (Ptr != End)
434    return make_error<GenericBinaryError>("Linking section ended prematurely",
435                                          object_error::parse_failed);
436  return Error::success();
437}
438
439WasmSection* WasmObjectFile::findCustomSectionByName(StringRef Name) {
440  for (WasmSection& Section : Sections) {
441    if (Section.Type == wasm::WASM_SEC_CUSTOM && Section.Name == Name)
442      return &Section;
443  }
444  return nullptr;
445}
446
447WasmSection* WasmObjectFile::findSectionByType(uint32_t Type) {
448  assert(Type != wasm::WASM_SEC_CUSTOM);
449  for (WasmSection& Section : Sections) {
450    if (Section.Type == Type)
451      return &Section;
452  }
453  return nullptr;
454}
455
456Error WasmObjectFile::parseRelocSection(StringRef Name, const uint8_t *Ptr,
457                                        const uint8_t *End) {
458  uint8_t SectionCode = readVarint7(Ptr);
459  WasmSection* Section = nullptr;
460  if (SectionCode == wasm::WASM_SEC_CUSTOM) {
461    StringRef Name = readString(Ptr);
462    Section = findCustomSectionByName(Name);
463  } else {
464    Section = findSectionByType(SectionCode);
465  }
466  if (!Section)
467    return make_error<GenericBinaryError>("Invalid section code",
468                                          object_error::parse_failed);
469  uint32_t RelocCount = readVaruint32(Ptr);
470  while (RelocCount--) {
471    wasm::WasmRelocation Reloc;
472    memset(&Reloc, 0, sizeof(Reloc));
473    Reloc.Type = readVaruint32(Ptr);
474    Reloc.Offset = readVaruint32(Ptr);
475    Reloc.Index = readVaruint32(Ptr);
476    switch (Reloc.Type) {
477    case wasm::R_WEBASSEMBLY_FUNCTION_INDEX_LEB:
478    case wasm::R_WEBASSEMBLY_TABLE_INDEX_SLEB:
479    case wasm::R_WEBASSEMBLY_TABLE_INDEX_I32:
480    case wasm::R_WEBASSEMBLY_TYPE_INDEX_LEB:
481    case wasm::R_WEBASSEMBLY_GLOBAL_INDEX_LEB:
482      break;
483    case wasm::R_WEBASSEMBLY_MEMORY_ADDR_LEB:
484    case wasm::R_WEBASSEMBLY_MEMORY_ADDR_SLEB:
485    case wasm::R_WEBASSEMBLY_MEMORY_ADDR_I32:
486      Reloc.Addend = readVarint32(Ptr);
487      break;
488    default:
489      return make_error<GenericBinaryError>("Bad relocation type: " +
490                                                Twine(Reloc.Type),
491                                            object_error::parse_failed);
492    }
493    Section->Relocations.push_back(Reloc);
494  }
495  if (Ptr != End)
496    return make_error<GenericBinaryError>("Reloc section ended prematurely",
497                                          object_error::parse_failed);
498  return Error::success();
499}
500
501Error WasmObjectFile::parseCustomSection(WasmSection &Sec,
502                                         const uint8_t *Ptr, const uint8_t *End) {
503  Sec.Name = readString(Ptr);
504  if (Sec.Name == "name") {
505    if (Error Err = parseNameSection(Ptr, End))
506      return Err;
507  } else if (Sec.Name == "linking") {
508    if (Error Err = parseLinkingSection(Ptr, End))
509      return Err;
510  } else if (Sec.Name.startswith("reloc.")) {
511    if (Error Err = parseRelocSection(Sec.Name, Ptr, End))
512      return Err;
513  }
514  return Error::success();
515}
516
517Error WasmObjectFile::parseTypeSection(const uint8_t *Ptr, const uint8_t *End) {
518  uint32_t Count = readVaruint32(Ptr);
519  Signatures.reserve(Count);
520  while (Count--) {
521    wasm::WasmSignature Sig;
522    Sig.ReturnType = wasm::WASM_TYPE_NORESULT;
523    int8_t Form = readVarint7(Ptr);
524    if (Form != wasm::WASM_TYPE_FUNC) {
525      return make_error<GenericBinaryError>("Invalid signature type",
526                                            object_error::parse_failed);
527    }
528    uint32_t ParamCount = readVaruint32(Ptr);
529    Sig.ParamTypes.reserve(ParamCount);
530    while (ParamCount--) {
531      uint32_t ParamType = readVarint7(Ptr);
532      Sig.ParamTypes.push_back(ParamType);
533    }
534    uint32_t ReturnCount = readVaruint32(Ptr);
535    if (ReturnCount) {
536      if (ReturnCount != 1) {
537        return make_error<GenericBinaryError>(
538            "Multiple return types not supported", object_error::parse_failed);
539      }
540      Sig.ReturnType = readVarint7(Ptr);
541    }
542    Signatures.push_back(Sig);
543  }
544  if (Ptr != End)
545    return make_error<GenericBinaryError>("Type section ended prematurely",
546                                          object_error::parse_failed);
547  return Error::success();
548}
549
550Error WasmObjectFile::parseImportSection(const uint8_t *Ptr, const uint8_t *End) {
551  ImportSection = Sections.size();
552  uint32_t Count = readVaruint32(Ptr);
553  Imports.reserve(Count);
554  for (uint32_t i = 0; i < Count; i++) {
555    wasm::WasmImport Im;
556    Im.Module = readString(Ptr);
557    Im.Field = readString(Ptr);
558    Im.Kind = readUint8(Ptr);
559    switch (Im.Kind) {
560    case wasm::WASM_EXTERNAL_FUNCTION:
561      NumImportedFunctions++;
562      Im.SigIndex = readVaruint32(Ptr);
563      break;
564    case wasm::WASM_EXTERNAL_GLOBAL:
565      NumImportedGlobals++;
566      Im.Global.Type = readVarint7(Ptr);
567      Im.Global.Mutable = readVaruint1(Ptr);
568      break;
569    case wasm::WASM_EXTERNAL_MEMORY:
570      Im.Memory = readLimits(Ptr);
571      break;
572    case wasm::WASM_EXTERNAL_TABLE:
573      Im.Table = readTable(Ptr);
574      if (Im.Table.ElemType != wasm::WASM_TYPE_ANYFUNC)
575        return make_error<GenericBinaryError>("Invalid table element type",
576                                              object_error::parse_failed);
577      break;
578    default:
579      return make_error<GenericBinaryError>(
580          "Unexpected import kind", object_error::parse_failed);
581    }
582    Imports.push_back(Im);
583  }
584  if (Ptr != End)
585    return make_error<GenericBinaryError>("Import section ended prematurely",
586                                          object_error::parse_failed);
587  return Error::success();
588}
589
590Error WasmObjectFile::parseFunctionSection(const uint8_t *Ptr, const uint8_t *End) {
591  uint32_t Count = readVaruint32(Ptr);
592  FunctionTypes.reserve(Count);
593  while (Count--) {
594    FunctionTypes.push_back(readVaruint32(Ptr));
595  }
596  if (Ptr != End)
597    return make_error<GenericBinaryError>("Function section ended prematurely",
598                                          object_error::parse_failed);
599  return Error::success();
600}
601
602Error WasmObjectFile::parseTableSection(const uint8_t *Ptr, const uint8_t *End) {
603  uint32_t Count = readVaruint32(Ptr);
604  Tables.reserve(Count);
605  while (Count--) {
606    Tables.push_back(readTable(Ptr));
607    if (Tables.back().ElemType != wasm::WASM_TYPE_ANYFUNC) {
608      return make_error<GenericBinaryError>("Invalid table element type",
609                                            object_error::parse_failed);
610    }
611  }
612  if (Ptr != End)
613    return make_error<GenericBinaryError>("Table section ended prematurely",
614                                          object_error::parse_failed);
615  return Error::success();
616}
617
618Error WasmObjectFile::parseMemorySection(const uint8_t *Ptr, const uint8_t *End) {
619  uint32_t Count = readVaruint32(Ptr);
620  Memories.reserve(Count);
621  while (Count--) {
622    Memories.push_back(readLimits(Ptr));
623  }
624  if (Ptr != End)
625    return make_error<GenericBinaryError>("Memory section ended prematurely",
626                                          object_error::parse_failed);
627  return Error::success();
628}
629
630Error WasmObjectFile::parseGlobalSection(const uint8_t *Ptr, const uint8_t *End) {
631  uint32_t Count = readVaruint32(Ptr);
632  Globals.reserve(Count);
633  while (Count--) {
634    wasm::WasmGlobal Global;
635    Global.Type = readVarint7(Ptr);
636    Global.Mutable = readVaruint1(Ptr);
637    if (Error Err = readInitExpr(Global.InitExpr, Ptr))
638      return Err;
639    Globals.push_back(Global);
640  }
641  if (Ptr != End)
642    return make_error<GenericBinaryError>("Global section ended prematurely",
643                                          object_error::parse_failed);
644  return Error::success();
645}
646
647Error WasmObjectFile::parseExportSection(const uint8_t *Ptr, const uint8_t *End) {
648  ExportSection = Sections.size();
649  uint32_t Count = readVaruint32(Ptr);
650  Exports.reserve(Count);
651  for (uint32_t i = 0; i < Count; i++) {
652    wasm::WasmExport Ex;
653    Ex.Name = readString(Ptr);
654    Ex.Kind = readUint8(Ptr);
655    Ex.Index = readVaruint32(Ptr);
656    switch (Ex.Kind) {
657    case wasm::WASM_EXTERNAL_FUNCTION:
658      if (Ex.Index >= FunctionTypes.size() + NumImportedFunctions)
659        return make_error<GenericBinaryError>("Invalid function export",
660                                              object_error::parse_failed);
661      break;
662    case wasm::WASM_EXTERNAL_GLOBAL: {
663      if (Ex.Index >= Globals.size() + NumImportedGlobals)
664        return make_error<GenericBinaryError>("Invalid global export",
665                                              object_error::parse_failed);
666      break;
667    }
668    case wasm::WASM_EXTERNAL_MEMORY:
669    case wasm::WASM_EXTERNAL_TABLE:
670      break;
671    default:
672      return make_error<GenericBinaryError>(
673          "Unexpected export kind", object_error::parse_failed);
674    }
675    Exports.push_back(Ex);
676  }
677  if (Ptr != End)
678    return make_error<GenericBinaryError>("Export section ended prematurely",
679                                          object_error::parse_failed);
680  return Error::success();
681}
682
683bool WasmObjectFile::isValidFunctionIndex(uint32_t Index) const {
684  return Index < FunctionTypes.size() + NumImportedFunctions;
685}
686
687Error WasmObjectFile::parseStartSection(const uint8_t *Ptr, const uint8_t *End) {
688  StartFunction = readVaruint32(Ptr);
689  if (!isValidFunctionIndex(StartFunction))
690    return make_error<GenericBinaryError>("Invalid start function",
691                                          object_error::parse_failed);
692  return Error::success();
693}
694
695Error WasmObjectFile::parseCodeSection(const uint8_t *Ptr, const uint8_t *End) {
696  const uint8_t *CodeSectionStart = Ptr;
697  uint32_t FunctionCount = readVaruint32(Ptr);
698  if (FunctionCount != FunctionTypes.size()) {
699    return make_error<GenericBinaryError>("Invalid function count",
700                                          object_error::parse_failed);
701  }
702
703  while (FunctionCount--) {
704    wasm::WasmFunction Function;
705    const uint8_t *FunctionStart = Ptr;
706    uint32_t Size = readVaruint32(Ptr);
707    const uint8_t *FunctionEnd = Ptr + Size;
708
709    Function.CodeSectionOffset = FunctionStart - CodeSectionStart;
710    Function.Size = FunctionEnd - FunctionStart;
711
712    uint32_t NumLocalDecls = readVaruint32(Ptr);
713    Function.Locals.reserve(NumLocalDecls);
714    while (NumLocalDecls--) {
715      wasm::WasmLocalDecl Decl;
716      Decl.Count = readVaruint32(Ptr);
717      Decl.Type = readVarint7(Ptr);
718      Function.Locals.push_back(Decl);
719    }
720
721    uint32_t BodySize = FunctionEnd - Ptr;
722    Function.Body = ArrayRef<uint8_t>(Ptr, BodySize);
723    Ptr += BodySize;
724    assert(Ptr == FunctionEnd);
725    Functions.push_back(Function);
726  }
727  if (Ptr != End)
728    return make_error<GenericBinaryError>("Code section ended prematurely",
729                                          object_error::parse_failed);
730  return Error::success();
731}
732
733Error WasmObjectFile::parseElemSection(const uint8_t *Ptr, const uint8_t *End) {
734  uint32_t Count = readVaruint32(Ptr);
735  ElemSegments.reserve(Count);
736  while (Count--) {
737    wasm::WasmElemSegment Segment;
738    Segment.TableIndex = readVaruint32(Ptr);
739    if (Segment.TableIndex != 0) {
740      return make_error<GenericBinaryError>("Invalid TableIndex",
741                                            object_error::parse_failed);
742    }
743    if (Error Err = readInitExpr(Segment.Offset, Ptr))
744      return Err;
745    uint32_t NumElems = readVaruint32(Ptr);
746    while (NumElems--) {
747      Segment.Functions.push_back(readVaruint32(Ptr));
748    }
749    ElemSegments.push_back(Segment);
750  }
751  if (Ptr != End)
752    return make_error<GenericBinaryError>("Elem section ended prematurely",
753                                          object_error::parse_failed);
754  return Error::success();
755}
756
757Error WasmObjectFile::parseDataSection(const uint8_t *Ptr, const uint8_t *End) {
758  const uint8_t *Start = Ptr;
759  uint32_t Count = readVaruint32(Ptr);
760  DataSegments.reserve(Count);
761  while (Count--) {
762    WasmSegment Segment;
763    Segment.Data.MemoryIndex = readVaruint32(Ptr);
764    if (Error Err = readInitExpr(Segment.Data.Offset, Ptr))
765      return Err;
766    uint32_t Size = readVaruint32(Ptr);
767    Segment.Data.Content = ArrayRef<uint8_t>(Ptr, Size);
768    Segment.Data.Alignment = 0;
769    Segment.Data.Flags = 0;
770    Segment.SectionOffset = Ptr - Start;
771    Ptr += Size;
772    DataSegments.push_back(Segment);
773  }
774  if (Ptr != End)
775    return make_error<GenericBinaryError>("Data section ended prematurely",
776                                          object_error::parse_failed);
777  return Error::success();
778}
779
780const uint8_t *WasmObjectFile::getPtr(size_t Offset) const {
781  return reinterpret_cast<const uint8_t *>(getData().substr(Offset, 1).data());
782}
783
784const wasm::WasmObjectHeader &WasmObjectFile::getHeader() const {
785  return Header;
786}
787
788void WasmObjectFile::moveSymbolNext(DataRefImpl &Symb) const { Symb.d.a++; }
789
790uint32_t WasmObjectFile::getSymbolFlags(DataRefImpl Symb) const {
791  uint32_t Result = SymbolRef::SF_None;
792  const WasmSymbol &Sym = getWasmSymbol(Symb);
793
794  DEBUG(dbgs() << "getSymbolFlags: ptr=" << &Sym << " " << Sym << "\n");
795  if (Sym.isWeak())
796    Result |= SymbolRef::SF_Weak;
797  if (!Sym.isLocal())
798    Result |= SymbolRef::SF_Global;
799  if (Sym.isHidden())
800    Result |= SymbolRef::SF_Hidden;
801
802  switch (Sym.Type) {
803  case WasmSymbol::SymbolType::FUNCTION_IMPORT:
804    Result |= SymbolRef::SF_Undefined | SymbolRef::SF_Executable;
805    break;
806  case WasmSymbol::SymbolType::FUNCTION_EXPORT:
807    Result |= SymbolRef::SF_Executable;
808    break;
809  case WasmSymbol::SymbolType::DEBUG_FUNCTION_NAME:
810    Result |= SymbolRef::SF_Executable;
811    Result |= SymbolRef::SF_FormatSpecific;
812    break;
813  case WasmSymbol::SymbolType::GLOBAL_IMPORT:
814    Result |= SymbolRef::SF_Undefined;
815    break;
816  case WasmSymbol::SymbolType::GLOBAL_EXPORT:
817    break;
818  }
819
820  return Result;
821}
822
823basic_symbol_iterator WasmObjectFile::symbol_begin() const {
824  DataRefImpl Ref;
825  Ref.d.a = 0;
826  return BasicSymbolRef(Ref, this);
827}
828
829basic_symbol_iterator WasmObjectFile::symbol_end() const {
830  DataRefImpl Ref;
831  Ref.d.a = Symbols.size();
832  return BasicSymbolRef(Ref, this);
833}
834
835const WasmSymbol &WasmObjectFile::getWasmSymbol(const DataRefImpl &Symb) const {
836  return Symbols[Symb.d.a];
837}
838
839const WasmSymbol &WasmObjectFile::getWasmSymbol(const SymbolRef &Symb) const {
840  return getWasmSymbol(Symb.getRawDataRefImpl());
841}
842
843Expected<StringRef> WasmObjectFile::getSymbolName(DataRefImpl Symb) const {
844  return getWasmSymbol(Symb).Name;
845}
846
847Expected<uint64_t> WasmObjectFile::getSymbolAddress(DataRefImpl Symb) const {
848  return getSymbolValue(Symb);
849}
850
851uint64_t WasmObjectFile::getWasmSymbolValue(const WasmSymbol& Sym) const {
852  switch (Sym.Type) {
853  case WasmSymbol::SymbolType::FUNCTION_IMPORT:
854  case WasmSymbol::SymbolType::GLOBAL_IMPORT:
855  case WasmSymbol::SymbolType::FUNCTION_EXPORT:
856  case WasmSymbol::SymbolType::DEBUG_FUNCTION_NAME:
857    return Sym.ElementIndex;
858  case WasmSymbol::SymbolType::GLOBAL_EXPORT: {
859    uint32_t GlobalIndex = Sym.ElementIndex - NumImportedGlobals;
860    assert(GlobalIndex < Globals.size());
861    const wasm::WasmGlobal& Global = Globals[GlobalIndex];
862    // WasmSymbols correspond only to I32_CONST globals
863    assert(Global.InitExpr.Opcode == wasm::WASM_OPCODE_I32_CONST);
864    return Global.InitExpr.Value.Int32;
865  }
866  }
867  llvm_unreachable("invalid symbol type");
868}
869
870uint64_t WasmObjectFile::getSymbolValueImpl(DataRefImpl Symb) const {
871  return getWasmSymbolValue(getWasmSymbol(Symb));
872}
873
874uint32_t WasmObjectFile::getSymbolAlignment(DataRefImpl Symb) const {
875  llvm_unreachable("not yet implemented");
876  return 0;
877}
878
879uint64_t WasmObjectFile::getCommonSymbolSizeImpl(DataRefImpl Symb) const {
880  llvm_unreachable("not yet implemented");
881  return 0;
882}
883
884Expected<SymbolRef::Type>
885WasmObjectFile::getSymbolType(DataRefImpl Symb) const {
886  const WasmSymbol &Sym = getWasmSymbol(Symb);
887
888  switch (Sym.Type) {
889  case WasmSymbol::SymbolType::FUNCTION_IMPORT:
890  case WasmSymbol::SymbolType::FUNCTION_EXPORT:
891  case WasmSymbol::SymbolType::DEBUG_FUNCTION_NAME:
892    return SymbolRef::ST_Function;
893  case WasmSymbol::SymbolType::GLOBAL_IMPORT:
894  case WasmSymbol::SymbolType::GLOBAL_EXPORT:
895    return SymbolRef::ST_Data;
896  }
897
898  llvm_unreachable("Unknown WasmSymbol::SymbolType");
899  return SymbolRef::ST_Other;
900}
901
902Expected<section_iterator>
903WasmObjectFile::getSymbolSection(DataRefImpl Symb) const {
904  DataRefImpl Ref;
905  Ref.d.a = getWasmSymbol(Symb).Section;
906  return section_iterator(SectionRef(Ref, this));
907}
908
909void WasmObjectFile::moveSectionNext(DataRefImpl &Sec) const { Sec.d.a++; }
910
911std::error_code WasmObjectFile::getSectionName(DataRefImpl Sec,
912                                               StringRef &Res) const {
913  const WasmSection &S = Sections[Sec.d.a];
914#define ECase(X)                                                               \
915  case wasm::WASM_SEC_##X:                                                     \
916    Res = #X;                                                                  \
917    break
918  switch (S.Type) {
919    ECase(TYPE);
920    ECase(IMPORT);
921    ECase(FUNCTION);
922    ECase(TABLE);
923    ECase(MEMORY);
924    ECase(GLOBAL);
925    ECase(EXPORT);
926    ECase(START);
927    ECase(ELEM);
928    ECase(CODE);
929    ECase(DATA);
930  case wasm::WASM_SEC_CUSTOM:
931    Res = S.Name;
932    break;
933  default:
934    return object_error::invalid_section_index;
935  }
936#undef ECase
937  return std::error_code();
938}
939
940uint64_t WasmObjectFile::getSectionAddress(DataRefImpl Sec) const { return 0; }
941
942uint64_t WasmObjectFile::getSectionIndex(DataRefImpl Sec) const {
943  return Sec.d.a;
944}
945
946uint64_t WasmObjectFile::getSectionSize(DataRefImpl Sec) const {
947  const WasmSection &S = Sections[Sec.d.a];
948  return S.Content.size();
949}
950
951std::error_code WasmObjectFile::getSectionContents(DataRefImpl Sec,
952                                                   StringRef &Res) const {
953  const WasmSection &S = Sections[Sec.d.a];
954  // This will never fail since wasm sections can never be empty (user-sections
955  // must have a name and non-user sections each have a defined structure).
956  Res = StringRef(reinterpret_cast<const char *>(S.Content.data()),
957                  S.Content.size());
958  return std::error_code();
959}
960
961uint64_t WasmObjectFile::getSectionAlignment(DataRefImpl Sec) const {
962  return 1;
963}
964
965bool WasmObjectFile::isSectionCompressed(DataRefImpl Sec) const {
966  return false;
967}
968
969bool WasmObjectFile::isSectionText(DataRefImpl Sec) const {
970  return getWasmSection(Sec).Type == wasm::WASM_SEC_CODE;
971}
972
973bool WasmObjectFile::isSectionData(DataRefImpl Sec) const {
974  return getWasmSection(Sec).Type == wasm::WASM_SEC_DATA;
975}
976
977bool WasmObjectFile::isSectionBSS(DataRefImpl Sec) const { return false; }
978
979bool WasmObjectFile::isSectionVirtual(DataRefImpl Sec) const { return false; }
980
981bool WasmObjectFile::isSectionBitcode(DataRefImpl Sec) const { return false; }
982
983relocation_iterator WasmObjectFile::section_rel_begin(DataRefImpl Ref) const {
984  DataRefImpl RelocRef;
985  RelocRef.d.a = Ref.d.a;
986  RelocRef.d.b = 0;
987  return relocation_iterator(RelocationRef(RelocRef, this));
988}
989
990relocation_iterator WasmObjectFile::section_rel_end(DataRefImpl Ref) const {
991  const WasmSection &Sec = getWasmSection(Ref);
992  DataRefImpl RelocRef;
993  RelocRef.d.a = Ref.d.a;
994  RelocRef.d.b = Sec.Relocations.size();
995  return relocation_iterator(RelocationRef(RelocRef, this));
996}
997
998void WasmObjectFile::moveRelocationNext(DataRefImpl &Rel) const {
999  Rel.d.b++;
1000}
1001
1002uint64_t WasmObjectFile::getRelocationOffset(DataRefImpl Ref) const {
1003  const wasm::WasmRelocation &Rel = getWasmRelocation(Ref);
1004  return Rel.Offset;
1005}
1006
1007symbol_iterator WasmObjectFile::getRelocationSymbol(DataRefImpl Rel) const {
1008  llvm_unreachable("not yet implemented");
1009  SymbolRef Ref;
1010  return symbol_iterator(Ref);
1011}
1012
1013uint64_t WasmObjectFile::getRelocationType(DataRefImpl Ref) const {
1014  const wasm::WasmRelocation &Rel = getWasmRelocation(Ref);
1015  return Rel.Type;
1016}
1017
1018void WasmObjectFile::getRelocationTypeName(
1019    DataRefImpl Ref, SmallVectorImpl<char> &Result) const {
1020  const wasm::WasmRelocation& Rel = getWasmRelocation(Ref);
1021  StringRef Res = "Unknown";
1022
1023#define WASM_RELOC(name, value)  \
1024  case wasm::name:              \
1025    Res = #name;               \
1026    break;
1027
1028  switch (Rel.Type) {
1029#include "llvm/BinaryFormat/WasmRelocs.def"
1030  }
1031
1032#undef WASM_RELOC
1033
1034  Result.append(Res.begin(), Res.end());
1035}
1036
1037section_iterator WasmObjectFile::section_begin() const {
1038  DataRefImpl Ref;
1039  Ref.d.a = 0;
1040  return section_iterator(SectionRef(Ref, this));
1041}
1042
1043section_iterator WasmObjectFile::section_end() const {
1044  DataRefImpl Ref;
1045  Ref.d.a = Sections.size();
1046  return section_iterator(SectionRef(Ref, this));
1047}
1048
1049uint8_t WasmObjectFile::getBytesInAddress() const { return 4; }
1050
1051StringRef WasmObjectFile::getFileFormatName() const { return "WASM"; }
1052
1053Triple::ArchType WasmObjectFile::getArch() const { return Triple::wasm32; }
1054
1055SubtargetFeatures WasmObjectFile::getFeatures() const {
1056  return SubtargetFeatures();
1057}
1058
1059bool WasmObjectFile::isRelocatableObject() const {
1060  return HasLinkingSection;
1061}
1062
1063const WasmSection &WasmObjectFile::getWasmSection(DataRefImpl Ref) const {
1064  assert(Ref.d.a < Sections.size());
1065  return Sections[Ref.d.a];
1066}
1067
1068const WasmSection &
1069WasmObjectFile::getWasmSection(const SectionRef &Section) const {
1070  return getWasmSection(Section.getRawDataRefImpl());
1071}
1072
1073const wasm::WasmRelocation &
1074WasmObjectFile::getWasmRelocation(const RelocationRef &Ref) const {
1075  return getWasmRelocation(Ref.getRawDataRefImpl());
1076}
1077
1078const wasm::WasmRelocation &
1079WasmObjectFile::getWasmRelocation(DataRefImpl Ref) const {
1080  assert(Ref.d.a < Sections.size());
1081  const WasmSection& Sec = Sections[Ref.d.a];
1082  assert(Ref.d.b < Sec.Relocations.size());
1083  return Sec.Relocations[Ref.d.b];
1084}
1085