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 
33 using namespace llvm;
34 using namespace object;
35 
36 Expected<std::unique_ptr<WasmObjectFile>>
37 ObjectFile::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 
51 static uint8_t readUint8(const uint8_t *&Ptr) { return *Ptr++; }
52 
53 static uint32_t readUint32(const uint8_t *&Ptr) {
54   uint32_t Result = support::endian::read32le(Ptr);
55   Ptr += sizeof(Result);
56   return Result;
57 }
58 
59 static 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 
66 static 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 
73 static 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 
80 static 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 
87 static 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 
94 static 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 
100 static 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 
106 static uint8_t readVaruint7(const uint8_t *&Ptr) {
107   uint64_t result = readULEB128(Ptr);
108   assert(result <= VARUINT7_MAX);
109   return result;
110 }
111 
112 static 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 
118 static uint32_t readVaruint32(const uint8_t *&Ptr) {
119   uint64_t result = readULEB128(Ptr);
120   assert(result <= UINT32_MAX);
121   return result;
122 }
123 
124 static int64_t readVarint64(const uint8_t *&Ptr) {
125   return readLEB128(Ptr);
126 }
127 
128 static uint8_t readOpcode(const uint8_t *&Ptr) {
129   return readUint8(Ptr);
130 }
131 
132 static 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 
164 static 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 
173 static 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 
180 static Error readSection(WasmSection &Section, const uint8_t *&Ptr,
181                          const uint8_t *Start) {
182   // TODO(sbc): Avoid reading past EOF in the case of malformed files.
183   Section.Offset = Ptr - Start;
184   Section.Type = readVaruint7(Ptr);
185   uint32_t Size = readVaruint32(Ptr);
186   if (Size == 0)
187     return make_error<StringError>("Zero length section",
188                                    object_error::parse_failed);
189   Section.Content = ArrayRef<uint8_t>(Ptr, Size);
190   Ptr += Size;
191   return Error::success();
192 }
193 
194 WasmObjectFile::WasmObjectFile(MemoryBufferRef Buffer, Error &Err)
195     : ObjectFile(Binary::ID_Wasm, Buffer) {
196   LinkingData.DataAlignment = 0;
197   LinkingData.DataSize = 0;
198 
199   ErrorAsOutParameter ErrAsOutParam(&Err);
200   Header.Magic = getData().substr(0, 4);
201   if (Header.Magic != StringRef("\0asm", 4)) {
202     Err = make_error<StringError>("Bad magic number",
203                                   object_error::parse_failed);
204     return;
205   }
206 
207   const uint8_t *Eof = getPtr(getData().size());
208   const uint8_t *Ptr = getPtr(4);
209 
210   if (Ptr + 4 > Eof) {
211     Err = make_error<StringError>("Missing version number",
212                                   object_error::parse_failed);
213     return;
214   }
215 
216   Header.Version = readUint32(Ptr);
217   if (Header.Version != wasm::WasmVersion) {
218     Err = make_error<StringError>("Bad version number",
219                                   object_error::parse_failed);
220     return;
221   }
222 
223   WasmSection Sec;
224   while (Ptr < Eof) {
225     if ((Err = readSection(Sec, Ptr, getPtr(0))))
226       return;
227     if ((Err = parseSection(Sec)))
228       return;
229 
230     Sections.push_back(Sec);
231   }
232 }
233 
234 Error WasmObjectFile::parseSection(WasmSection &Sec) {
235   const uint8_t* Start = Sec.Content.data();
236   const uint8_t* End = Start + Sec.Content.size();
237   switch (Sec.Type) {
238   case wasm::WASM_SEC_CUSTOM:
239     return parseCustomSection(Sec, Start, End);
240   case wasm::WASM_SEC_TYPE:
241     return parseTypeSection(Start, End);
242   case wasm::WASM_SEC_IMPORT:
243     return parseImportSection(Start, End);
244   case wasm::WASM_SEC_FUNCTION:
245     return parseFunctionSection(Start, End);
246   case wasm::WASM_SEC_TABLE:
247     return parseTableSection(Start, End);
248   case wasm::WASM_SEC_MEMORY:
249     return parseMemorySection(Start, End);
250   case wasm::WASM_SEC_GLOBAL:
251     return parseGlobalSection(Start, End);
252   case wasm::WASM_SEC_EXPORT:
253     return parseExportSection(Start, End);
254   case wasm::WASM_SEC_START:
255     return parseStartSection(Start, End);
256   case wasm::WASM_SEC_ELEM:
257     return parseElemSection(Start, End);
258   case wasm::WASM_SEC_CODE:
259     return parseCodeSection(Start, End);
260   case wasm::WASM_SEC_DATA:
261     return parseDataSection(Start, End);
262   default:
263     return make_error<GenericBinaryError>("Bad section type",
264                                           object_error::parse_failed);
265   }
266 }
267 
268 Error WasmObjectFile::parseNameSection(const uint8_t *Ptr, const uint8_t *End) {
269   while (Ptr < End) {
270     uint8_t Type = readVarint7(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         StringRef Name = readString(Ptr);
279         if (!Name.empty())
280           Symbols.emplace_back(Name,
281                                WasmSymbol::SymbolType::DEBUG_FUNCTION_NAME,
282                                Sections.size(), Index);
283       }
284       break;
285     }
286     // Ignore local names for now
287     case wasm::WASM_NAMES_LOCAL:
288     default:
289       Ptr += Size;
290       break;
291     }
292     if (Ptr != SubSectionEnd)
293       return make_error<GenericBinaryError>("Name sub-section ended prematurely",
294                                             object_error::parse_failed);
295   }
296 
297   if (Ptr != End)
298     return make_error<GenericBinaryError>("Name section ended prematurely",
299                                           object_error::parse_failed);
300   return Error::success();
301 }
302 
303 Error WasmObjectFile::parseLinkingSection(const uint8_t *Ptr,
304                                           const uint8_t *End) {
305   HasLinkingSection = true;
306   while (Ptr < End) {
307     uint8_t Type = readVarint7(Ptr);
308     uint32_t Size = readVaruint32(Ptr);
309     const uint8_t *SubSectionEnd = Ptr + Size;
310     switch (Type) {
311     case wasm::WASM_SYMBOL_INFO: {
312       uint32_t Count = readVaruint32(Ptr);
313       while (Count--) {
314         StringRef Symbol = readString(Ptr);
315         DEBUG(dbgs() << "reading syminfo: " << Symbol << "\n");
316         uint32_t Flags = readVaruint32(Ptr);
317         auto iter = SymbolMap.find(Symbol);
318         if (iter == SymbolMap.end()) {
319           return make_error<GenericBinaryError>(
320               "Invalid symbol name in linking section: " + Symbol,
321               object_error::parse_failed);
322         }
323         uint32_t SymIndex = iter->second;
324         assert(SymIndex < Symbols.size());
325         Symbols[SymIndex].Flags = Flags;
326         DEBUG(dbgs() << "Set symbol flags index:"
327                      << SymIndex << " name:"
328                      << Symbols[SymIndex].Name << " exptected:"
329                      << Symbol << " flags: " << Flags << "\n");
330       }
331       break;
332     }
333     case wasm::WASM_DATA_SIZE:
334       LinkingData.DataSize = readVaruint32(Ptr);
335       break;
336     case wasm::WASM_DATA_ALIGNMENT:
337       LinkingData.DataAlignment = readVaruint32(Ptr);
338       break;
339     case wasm::WASM_STACK_POINTER:
340     default:
341       Ptr += Size;
342       break;
343     }
344     if (Ptr != SubSectionEnd)
345       return make_error<GenericBinaryError>(
346           "Linking sub-section ended prematurely", object_error::parse_failed);
347   }
348   if (Ptr != End)
349     return make_error<GenericBinaryError>("Linking section ended prematurely",
350                                           object_error::parse_failed);
351   return Error::success();
352 }
353 
354 WasmSection* WasmObjectFile::findCustomSectionByName(StringRef Name) {
355   for (WasmSection& Section : Sections) {
356     if (Section.Type == wasm::WASM_SEC_CUSTOM && Section.Name == Name)
357       return &Section;
358   }
359   return nullptr;
360 }
361 
362 WasmSection* WasmObjectFile::findSectionByType(uint32_t Type) {
363   assert(Type != wasm::WASM_SEC_CUSTOM);
364   for (WasmSection& Section : Sections) {
365     if (Section.Type == Type)
366       return &Section;
367   }
368   return nullptr;
369 }
370 
371 Error WasmObjectFile::parseRelocSection(StringRef Name, const uint8_t *Ptr,
372                                         const uint8_t *End) {
373   uint8_t SectionCode = readVarint7(Ptr);
374   WasmSection* Section = nullptr;
375   if (SectionCode == wasm::WASM_SEC_CUSTOM) {
376     StringRef Name = readString(Ptr);
377     Section = findCustomSectionByName(Name);
378   } else {
379     Section = findSectionByType(SectionCode);
380   }
381   if (!Section)
382     return make_error<GenericBinaryError>("Invalid section code",
383                                           object_error::parse_failed);
384   uint32_t RelocCount = readVaruint32(Ptr);
385   while (RelocCount--) {
386     wasm::WasmRelocation Reloc;
387     memset(&Reloc, 0, sizeof(Reloc));
388     Reloc.Type = readVaruint32(Ptr);
389     Reloc.Offset = readVaruint32(Ptr);
390     Reloc.Index = readVaruint32(Ptr);
391     switch (Reloc.Type) {
392     case wasm::R_WEBASSEMBLY_FUNCTION_INDEX_LEB:
393     case wasm::R_WEBASSEMBLY_TABLE_INDEX_SLEB:
394     case wasm::R_WEBASSEMBLY_TABLE_INDEX_I32:
395     case wasm::R_WEBASSEMBLY_TYPE_INDEX_LEB:
396     case wasm::R_WEBASSEMBLY_GLOBAL_INDEX_LEB:
397       break;
398     case wasm::R_WEBASSEMBLY_GLOBAL_ADDR_LEB:
399     case wasm::R_WEBASSEMBLY_GLOBAL_ADDR_SLEB:
400     case wasm::R_WEBASSEMBLY_GLOBAL_ADDR_I32:
401       Reloc.Addend = readVarint32(Ptr);
402       break;
403     default:
404       return make_error<GenericBinaryError>("Bad relocation type: " +
405                                                 Twine(Reloc.Type),
406                                             object_error::parse_failed);
407     }
408     Section->Relocations.push_back(Reloc);
409   }
410   if (Ptr != End)
411     return make_error<GenericBinaryError>("Reloc section ended prematurely",
412                                           object_error::parse_failed);
413   return Error::success();
414 }
415 
416 Error WasmObjectFile::parseCustomSection(WasmSection &Sec,
417                                          const uint8_t *Ptr, const uint8_t *End) {
418   Sec.Name = readString(Ptr);
419   if (Sec.Name == "name") {
420     if (Error Err = parseNameSection(Ptr, End))
421       return Err;
422   } else if (Sec.Name == "linking") {
423     if (Error Err = parseLinkingSection(Ptr, End))
424       return Err;
425   } else if (Sec.Name.startswith("reloc.")) {
426     if (Error Err = parseRelocSection(Sec.Name, Ptr, End))
427       return Err;
428   }
429   return Error::success();
430 }
431 
432 Error WasmObjectFile::parseTypeSection(const uint8_t *Ptr, const uint8_t *End) {
433   uint32_t Count = readVaruint32(Ptr);
434   Signatures.reserve(Count);
435   while (Count--) {
436     wasm::WasmSignature Sig;
437     Sig.ReturnType = wasm::WASM_TYPE_NORESULT;
438     int8_t Form = readVarint7(Ptr);
439     if (Form != wasm::WASM_TYPE_FUNC) {
440       return make_error<GenericBinaryError>("Invalid signature type",
441                                             object_error::parse_failed);
442     }
443     uint32_t ParamCount = readVaruint32(Ptr);
444     Sig.ParamTypes.reserve(ParamCount);
445     while (ParamCount--) {
446       uint32_t ParamType = readVarint7(Ptr);
447       Sig.ParamTypes.push_back(ParamType);
448     }
449     uint32_t ReturnCount = readVaruint32(Ptr);
450     if (ReturnCount) {
451       if (ReturnCount != 1) {
452         return make_error<GenericBinaryError>(
453             "Multiple return types not supported", object_error::parse_failed);
454       }
455       Sig.ReturnType = readVarint7(Ptr);
456     }
457     Signatures.push_back(Sig);
458   }
459   if (Ptr != End)
460     return make_error<GenericBinaryError>("Type section ended prematurely",
461                                           object_error::parse_failed);
462   return Error::success();
463 }
464 
465 Error WasmObjectFile::parseImportSection(const uint8_t *Ptr, const uint8_t *End) {
466   uint32_t Count = readVaruint32(Ptr);
467   Imports.reserve(Count);
468   for (uint32_t i = 0; i < Count; i++) {
469     wasm::WasmImport Im;
470     Im.Module = readString(Ptr);
471     Im.Field = readString(Ptr);
472     Im.Kind = readUint8(Ptr);
473     switch (Im.Kind) {
474     case wasm::WASM_EXTERNAL_FUNCTION:
475       Im.SigIndex = readVaruint32(Ptr);
476       SymbolMap.try_emplace(Im.Field, Symbols.size());
477       Symbols.emplace_back(Im.Field, WasmSymbol::SymbolType::FUNCTION_IMPORT,
478                            Sections.size(), i);
479       DEBUG(dbgs() << "Adding import: " << Symbols.back()
480                    << " sym index:" << Symbols.size() << "\n");
481       break;
482     case wasm::WASM_EXTERNAL_GLOBAL:
483       Im.Global.Type = readVarint7(Ptr);
484       Im.Global.Mutable = readVaruint1(Ptr);
485       SymbolMap.try_emplace(Im.Field, Symbols.size());
486       Symbols.emplace_back(Im.Field, WasmSymbol::SymbolType::GLOBAL_IMPORT,
487                            Sections.size(), i);
488       DEBUG(dbgs() << "Adding import: " << Symbols.back()
489                    << " sym index:" << Symbols.size() << "\n");
490       break;
491     case wasm::WASM_EXTERNAL_MEMORY:
492       Im.Memory = readLimits(Ptr);
493       break;
494     case wasm::WASM_EXTERNAL_TABLE:
495       Im.Table = readTable(Ptr);
496       if (Im.Table.ElemType != wasm::WASM_TYPE_ANYFUNC) {
497         return make_error<GenericBinaryError>("Invalid table element type",
498                                               object_error::parse_failed);
499       }
500       break;
501     default:
502       return make_error<GenericBinaryError>(
503           "Unexpected import kind", object_error::parse_failed);
504     }
505     Imports.push_back(Im);
506   }
507   if (Ptr != End)
508     return make_error<GenericBinaryError>("Import section ended prematurely",
509                                           object_error::parse_failed);
510   return Error::success();
511 }
512 
513 Error WasmObjectFile::parseFunctionSection(const uint8_t *Ptr, const uint8_t *End) {
514   uint32_t Count = readVaruint32(Ptr);
515   FunctionTypes.reserve(Count);
516   while (Count--) {
517     FunctionTypes.push_back(readVaruint32(Ptr));
518   }
519   if (Ptr != End)
520     return make_error<GenericBinaryError>("Function section ended prematurely",
521                                           object_error::parse_failed);
522   return Error::success();
523 }
524 
525 Error WasmObjectFile::parseTableSection(const uint8_t *Ptr, const uint8_t *End) {
526   uint32_t Count = readVaruint32(Ptr);
527   Tables.reserve(Count);
528   while (Count--) {
529     Tables.push_back(readTable(Ptr));
530     if (Tables.back().ElemType != wasm::WASM_TYPE_ANYFUNC) {
531       return make_error<GenericBinaryError>("Invalid table element type",
532                                             object_error::parse_failed);
533     }
534   }
535   if (Ptr != End)
536     return make_error<GenericBinaryError>("Table section ended prematurely",
537                                           object_error::parse_failed);
538   return Error::success();
539 }
540 
541 Error WasmObjectFile::parseMemorySection(const uint8_t *Ptr, const uint8_t *End) {
542   uint32_t Count = readVaruint32(Ptr);
543   Memories.reserve(Count);
544   while (Count--) {
545     Memories.push_back(readLimits(Ptr));
546   }
547   if (Ptr != End)
548     return make_error<GenericBinaryError>("Memory section ended prematurely",
549                                           object_error::parse_failed);
550   return Error::success();
551 }
552 
553 Error WasmObjectFile::parseGlobalSection(const uint8_t *Ptr, const uint8_t *End) {
554   uint32_t Count = readVaruint32(Ptr);
555   Globals.reserve(Count);
556   while (Count--) {
557     wasm::WasmGlobal Global;
558     Global.Type = readVarint7(Ptr);
559     Global.Mutable = readVaruint1(Ptr);
560     if (Error Err = readInitExpr(Global.InitExpr, Ptr))
561       return Err;
562     Globals.push_back(Global);
563   }
564   if (Ptr != End)
565     return make_error<GenericBinaryError>("Global section ended prematurely",
566                                           object_error::parse_failed);
567   return Error::success();
568 }
569 
570 Error WasmObjectFile::parseExportSection(const uint8_t *Ptr, const uint8_t *End) {
571   uint32_t Count = readVaruint32(Ptr);
572   Exports.reserve(Count);
573   for (uint32_t i = 0; i < Count; i++) {
574     wasm::WasmExport Ex;
575     Ex.Name = readString(Ptr);
576     Ex.Kind = readUint8(Ptr);
577     Ex.Index = readVaruint32(Ptr);
578     WasmSymbol::SymbolType ExportType;
579     bool MakeSymbol = false;
580     switch (Ex.Kind) {
581     case wasm::WASM_EXTERNAL_FUNCTION:
582       ExportType = WasmSymbol::SymbolType::FUNCTION_EXPORT;
583       MakeSymbol = true;
584       break;
585     case wasm::WASM_EXTERNAL_GLOBAL:
586       ExportType = WasmSymbol::SymbolType::GLOBAL_EXPORT;
587       MakeSymbol = true;
588       break;
589     case wasm::WASM_EXTERNAL_MEMORY:
590     case wasm::WASM_EXTERNAL_TABLE:
591       break;
592     default:
593       return make_error<GenericBinaryError>(
594           "Unexpected export kind", object_error::parse_failed);
595     }
596     if (MakeSymbol) {
597       auto Pair = SymbolMap.try_emplace(Ex.Name, Symbols.size());
598       if (Pair.second) {
599         Symbols.emplace_back(Ex.Name, ExportType,
600                              Sections.size(), i);
601         DEBUG(dbgs() << "Adding export: " << Symbols.back()
602                      << " sym index:" << Symbols.size() << "\n");
603       } else {
604         uint32_t SymIndex = Pair.first->second;
605         Symbols[SymIndex] = WasmSymbol(Ex.Name, ExportType, Sections.size(), i);
606         DEBUG(dbgs() << "Replacing existing symbol:  " << Symbols[SymIndex]
607                      << " sym index:" << SymIndex << "\n");
608       }
609     }
610     Exports.push_back(Ex);
611   }
612   if (Ptr != End)
613     return make_error<GenericBinaryError>("Export section ended prematurely",
614                                           object_error::parse_failed);
615   return Error::success();
616 }
617 
618 Error WasmObjectFile::parseStartSection(const uint8_t *Ptr, const uint8_t *End) {
619   StartFunction = readVaruint32(Ptr);
620   if (StartFunction >= FunctionTypes.size())
621     return make_error<GenericBinaryError>("Invalid start function",
622                                           object_error::parse_failed);
623   return Error::success();
624 }
625 
626 Error WasmObjectFile::parseCodeSection(const uint8_t *Ptr, const uint8_t *End) {
627   uint32_t FunctionCount = readVaruint32(Ptr);
628   if (FunctionCount != FunctionTypes.size()) {
629     return make_error<GenericBinaryError>("Invalid function count",
630                                           object_error::parse_failed);
631   }
632 
633   CodeSection = ArrayRef<uint8_t>(Ptr, End - Ptr);
634 
635   while (FunctionCount--) {
636     wasm::WasmFunction Function;
637     uint32_t FunctionSize = readVaruint32(Ptr);
638     const uint8_t *FunctionEnd = Ptr + FunctionSize;
639 
640     uint32_t NumLocalDecls = readVaruint32(Ptr);
641     Function.Locals.reserve(NumLocalDecls);
642     while (NumLocalDecls--) {
643       wasm::WasmLocalDecl Decl;
644       Decl.Count = readVaruint32(Ptr);
645       Decl.Type = readVarint7(Ptr);
646       Function.Locals.push_back(Decl);
647     }
648 
649     uint32_t BodySize = FunctionEnd - Ptr;
650     Function.Body = ArrayRef<uint8_t>(Ptr, BodySize);
651     Ptr += BodySize;
652     assert(Ptr == FunctionEnd);
653     Functions.push_back(Function);
654   }
655   if (Ptr != End)
656     return make_error<GenericBinaryError>("Code section ended prematurely",
657                                           object_error::parse_failed);
658   return Error::success();
659 }
660 
661 Error WasmObjectFile::parseElemSection(const uint8_t *Ptr, const uint8_t *End) {
662   uint32_t Count = readVaruint32(Ptr);
663   ElemSegments.reserve(Count);
664   while (Count--) {
665     wasm::WasmElemSegment Segment;
666     Segment.TableIndex = readVaruint32(Ptr);
667     if (Segment.TableIndex != 0) {
668       return make_error<GenericBinaryError>("Invalid TableIndex",
669                                             object_error::parse_failed);
670     }
671     if (Error Err = readInitExpr(Segment.Offset, Ptr))
672       return Err;
673     uint32_t NumElems = readVaruint32(Ptr);
674     while (NumElems--) {
675       Segment.Functions.push_back(readVaruint32(Ptr));
676     }
677     ElemSegments.push_back(Segment);
678   }
679   if (Ptr != End)
680     return make_error<GenericBinaryError>("Elem section ended prematurely",
681                                           object_error::parse_failed);
682   return Error::success();
683 }
684 
685 Error WasmObjectFile::parseDataSection(const uint8_t *Ptr, const uint8_t *End) {
686   const uint8_t *Start = Ptr;
687   uint32_t Count = readVaruint32(Ptr);
688   DataSegments.reserve(Count);
689   while (Count--) {
690     WasmSegment Segment;
691     Segment.Data.MemoryIndex = readVaruint32(Ptr);
692     if (Error Err = readInitExpr(Segment.Data.Offset, Ptr))
693       return Err;
694     uint32_t Size = readVaruint32(Ptr);
695     Segment.Data.Content = ArrayRef<uint8_t>(Ptr, Size);
696     Segment.SectionOffset = Ptr - Start;
697     Ptr += Size;
698     DataSegments.push_back(Segment);
699   }
700   if (Ptr != End)
701     return make_error<GenericBinaryError>("Data section ended prematurely",
702                                           object_error::parse_failed);
703   return Error::success();
704 }
705 
706 const uint8_t *WasmObjectFile::getPtr(size_t Offset) const {
707   return reinterpret_cast<const uint8_t *>(getData().substr(Offset, 1).data());
708 }
709 
710 const wasm::WasmObjectHeader &WasmObjectFile::getHeader() const {
711   return Header;
712 }
713 
714 void WasmObjectFile::moveSymbolNext(DataRefImpl &Symb) const { Symb.d.a++; }
715 
716 uint32_t WasmObjectFile::getSymbolFlags(DataRefImpl Symb) const {
717   uint32_t Result = SymbolRef::SF_None;
718   const WasmSymbol &Sym = getWasmSymbol(Symb);
719 
720   DEBUG(dbgs() << "getSymbolFlags: ptr=" << &Sym << " " << Sym << "\n");
721   if (Sym.Flags & wasm::WASM_SYMBOL_FLAG_WEAK)
722     Result |= SymbolRef::SF_Weak;
723 
724   switch (Sym.Type) {
725   case WasmSymbol::SymbolType::FUNCTION_IMPORT:
726     Result |= SymbolRef::SF_Undefined | SymbolRef::SF_Executable;
727     break;
728   case WasmSymbol::SymbolType::FUNCTION_EXPORT:
729     Result |= SymbolRef::SF_Global | SymbolRef::SF_Executable;
730     break;
731   case WasmSymbol::SymbolType::DEBUG_FUNCTION_NAME:
732     Result |= SymbolRef::SF_Executable;
733     Result |= SymbolRef::SF_FormatSpecific;
734     break;
735   case WasmSymbol::SymbolType::GLOBAL_IMPORT:
736     Result |= SymbolRef::SF_Undefined;
737     break;
738   case WasmSymbol::SymbolType::GLOBAL_EXPORT:
739     Result |= SymbolRef::SF_Global;
740     break;
741   }
742 
743   return Result;
744 }
745 
746 basic_symbol_iterator WasmObjectFile::symbol_begin() const {
747   DataRefImpl Ref;
748   Ref.d.a = 0;
749   return BasicSymbolRef(Ref, this);
750 }
751 
752 basic_symbol_iterator WasmObjectFile::symbol_end() const {
753   DataRefImpl Ref;
754   Ref.d.a = Symbols.size();
755   return BasicSymbolRef(Ref, this);
756 }
757 
758 const WasmSymbol &WasmObjectFile::getWasmSymbol(const DataRefImpl &Symb) const {
759   return Symbols[Symb.d.a];
760 }
761 
762 const WasmSymbol &WasmObjectFile::getWasmSymbol(const SymbolRef &Symb) const {
763   return getWasmSymbol(Symb.getRawDataRefImpl());
764 }
765 
766 Expected<StringRef> WasmObjectFile::getSymbolName(DataRefImpl Symb) const {
767   return getWasmSymbol(Symb).Name;
768 }
769 
770 Expected<uint64_t> WasmObjectFile::getSymbolAddress(DataRefImpl Symb) const {
771   return getSymbolValue(Symb);
772 }
773 
774 uint64_t WasmObjectFile::getSymbolValueImpl(DataRefImpl Symb) const {
775   const WasmSymbol& Sym = getWasmSymbol(Symb);
776   switch (Sym.Type) {
777   case WasmSymbol::SymbolType::FUNCTION_IMPORT:
778   case WasmSymbol::SymbolType::GLOBAL_IMPORT:
779     return 0;
780   case WasmSymbol::SymbolType::FUNCTION_EXPORT:
781   case WasmSymbol::SymbolType::GLOBAL_EXPORT:
782     return Exports[Sym.ElementIndex].Index;
783   case WasmSymbol::SymbolType::DEBUG_FUNCTION_NAME:
784     return Sym.ElementIndex;
785   }
786   llvm_unreachable("invalid symbol type");
787 }
788 
789 uint32_t WasmObjectFile::getSymbolAlignment(DataRefImpl Symb) const {
790   llvm_unreachable("not yet implemented");
791   return 0;
792 }
793 
794 uint64_t WasmObjectFile::getCommonSymbolSizeImpl(DataRefImpl Symb) const {
795   llvm_unreachable("not yet implemented");
796   return 0;
797 }
798 
799 Expected<SymbolRef::Type>
800 WasmObjectFile::getSymbolType(DataRefImpl Symb) const {
801   const WasmSymbol &Sym = getWasmSymbol(Symb);
802 
803   switch (Sym.Type) {
804   case WasmSymbol::SymbolType::FUNCTION_IMPORT:
805   case WasmSymbol::SymbolType::FUNCTION_EXPORT:
806   case WasmSymbol::SymbolType::DEBUG_FUNCTION_NAME:
807     return SymbolRef::ST_Function;
808   case WasmSymbol::SymbolType::GLOBAL_IMPORT:
809   case WasmSymbol::SymbolType::GLOBAL_EXPORT:
810     return SymbolRef::ST_Data;
811   }
812 
813   llvm_unreachable("Unknown WasmSymbol::SymbolType");
814   return SymbolRef::ST_Other;
815 }
816 
817 Expected<section_iterator>
818 WasmObjectFile::getSymbolSection(DataRefImpl Symb) const {
819   DataRefImpl Ref;
820   Ref.d.a = getWasmSymbol(Symb).Section;
821   return section_iterator(SectionRef(Ref, this));
822 }
823 
824 void WasmObjectFile::moveSectionNext(DataRefImpl &Sec) const { Sec.d.a++; }
825 
826 std::error_code WasmObjectFile::getSectionName(DataRefImpl Sec,
827                                                StringRef &Res) const {
828   const WasmSection &S = Sections[Sec.d.a];
829 #define ECase(X)                                                               \
830   case wasm::WASM_SEC_##X:                                                     \
831     Res = #X;                                                                  \
832     break
833   switch (S.Type) {
834     ECase(TYPE);
835     ECase(IMPORT);
836     ECase(FUNCTION);
837     ECase(TABLE);
838     ECase(MEMORY);
839     ECase(GLOBAL);
840     ECase(EXPORT);
841     ECase(START);
842     ECase(ELEM);
843     ECase(CODE);
844     ECase(DATA);
845   case wasm::WASM_SEC_CUSTOM:
846     Res = S.Name;
847     break;
848   default:
849     return object_error::invalid_section_index;
850   }
851 #undef ECase
852   return std::error_code();
853 }
854 
855 uint64_t WasmObjectFile::getSectionAddress(DataRefImpl Sec) const { return 0; }
856 
857 uint64_t WasmObjectFile::getSectionIndex(DataRefImpl Sec) const {
858   return Sec.d.a;
859 }
860 
861 uint64_t WasmObjectFile::getSectionSize(DataRefImpl Sec) const {
862   const WasmSection &S = Sections[Sec.d.a];
863   return S.Content.size();
864 }
865 
866 std::error_code WasmObjectFile::getSectionContents(DataRefImpl Sec,
867                                                    StringRef &Res) const {
868   const WasmSection &S = Sections[Sec.d.a];
869   // This will never fail since wasm sections can never be empty (user-sections
870   // must have a name and non-user sections each have a defined structure).
871   Res = StringRef(reinterpret_cast<const char *>(S.Content.data()),
872                   S.Content.size());
873   return std::error_code();
874 }
875 
876 uint64_t WasmObjectFile::getSectionAlignment(DataRefImpl Sec) const {
877   return 1;
878 }
879 
880 bool WasmObjectFile::isSectionCompressed(DataRefImpl Sec) const {
881   return false;
882 }
883 
884 bool WasmObjectFile::isSectionText(DataRefImpl Sec) const {
885   return getWasmSection(Sec).Type == wasm::WASM_SEC_CODE;
886 }
887 
888 bool WasmObjectFile::isSectionData(DataRefImpl Sec) const {
889   return getWasmSection(Sec).Type == wasm::WASM_SEC_DATA;
890 }
891 
892 bool WasmObjectFile::isSectionBSS(DataRefImpl Sec) const { return false; }
893 
894 bool WasmObjectFile::isSectionVirtual(DataRefImpl Sec) const { return false; }
895 
896 bool WasmObjectFile::isSectionBitcode(DataRefImpl Sec) const { return false; }
897 
898 relocation_iterator WasmObjectFile::section_rel_begin(DataRefImpl Ref) const {
899   DataRefImpl RelocRef;
900   RelocRef.d.a = Ref.d.a;
901   RelocRef.d.b = 0;
902   return relocation_iterator(RelocationRef(RelocRef, this));
903 }
904 
905 relocation_iterator WasmObjectFile::section_rel_end(DataRefImpl Ref) const {
906   const WasmSection &Sec = getWasmSection(Ref);
907   DataRefImpl RelocRef;
908   RelocRef.d.a = Ref.d.a;
909   RelocRef.d.b = Sec.Relocations.size();
910   return relocation_iterator(RelocationRef(RelocRef, this));
911 }
912 
913 void WasmObjectFile::moveRelocationNext(DataRefImpl &Rel) const {
914   Rel.d.b++;
915 }
916 
917 uint64_t WasmObjectFile::getRelocationOffset(DataRefImpl Ref) const {
918   const wasm::WasmRelocation &Rel = getWasmRelocation(Ref);
919   return Rel.Offset;
920 }
921 
922 symbol_iterator WasmObjectFile::getRelocationSymbol(DataRefImpl Rel) const {
923   llvm_unreachable("not yet implemented");
924   SymbolRef Ref;
925   return symbol_iterator(Ref);
926 }
927 
928 uint64_t WasmObjectFile::getRelocationType(DataRefImpl Ref) const {
929   const wasm::WasmRelocation &Rel = getWasmRelocation(Ref);
930   return Rel.Type;
931 }
932 
933 void WasmObjectFile::getRelocationTypeName(
934     DataRefImpl Ref, SmallVectorImpl<char> &Result) const {
935   const wasm::WasmRelocation& Rel = getWasmRelocation(Ref);
936   StringRef Res = "Unknown";
937 
938 #define WASM_RELOC(name, value)  \
939   case wasm::name:              \
940     Res = #name;               \
941     break;
942 
943   switch (Rel.Type) {
944 #include "llvm/BinaryFormat/WasmRelocs/WebAssembly.def"
945   }
946 
947 #undef WASM_RELOC
948 
949   Result.append(Res.begin(), Res.end());
950 }
951 
952 section_iterator WasmObjectFile::section_begin() const {
953   DataRefImpl Ref;
954   Ref.d.a = 0;
955   return section_iterator(SectionRef(Ref, this));
956 }
957 
958 section_iterator WasmObjectFile::section_end() const {
959   DataRefImpl Ref;
960   Ref.d.a = Sections.size();
961   return section_iterator(SectionRef(Ref, this));
962 }
963 
964 uint8_t WasmObjectFile::getBytesInAddress() const { return 4; }
965 
966 StringRef WasmObjectFile::getFileFormatName() const { return "WASM"; }
967 
968 unsigned WasmObjectFile::getArch() const { return Triple::wasm32; }
969 
970 SubtargetFeatures WasmObjectFile::getFeatures() const {
971   return SubtargetFeatures();
972 }
973 
974 bool WasmObjectFile::isRelocatableObject() const {
975   return HasLinkingSection;
976 }
977 
978 const WasmSection &WasmObjectFile::getWasmSection(DataRefImpl Ref) const {
979   assert(Ref.d.a < Sections.size());
980   return Sections[Ref.d.a];
981 }
982 
983 const WasmSection &
984 WasmObjectFile::getWasmSection(const SectionRef &Section) const {
985   return getWasmSection(Section.getRawDataRefImpl());
986 }
987 
988 const wasm::WasmRelocation &
989 WasmObjectFile::getWasmRelocation(const RelocationRef &Ref) const {
990   return getWasmRelocation(Ref.getRawDataRefImpl());
991 }
992 
993 const wasm::WasmRelocation &
994 WasmObjectFile::getWasmRelocation(DataRefImpl Ref) const {
995   assert(Ref.d.a < Sections.size());
996   const WasmSection& Sec = Sections[Ref.d.a];
997   assert(Ref.d.b < Sec.Relocations.size());
998   return Sec.Relocations[Ref.d.b];
999 }
1000