1 //===- WasmObjectFile.cpp - Wasm object file implementation ---------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "llvm/ADT/ArrayRef.h"
10 #include "llvm/ADT/DenseSet.h"
11 #include "llvm/ADT/STLExtras.h"
12 #include "llvm/ADT/SmallSet.h"
13 #include "llvm/ADT/StringRef.h"
14 #include "llvm/ADT/StringSet.h"
15 #include "llvm/ADT/StringSwitch.h"
16 #include "llvm/ADT/Triple.h"
17 #include "llvm/BinaryFormat/Wasm.h"
18 #include "llvm/MC/SubtargetFeature.h"
19 #include "llvm/Object/Binary.h"
20 #include "llvm/Object/Error.h"
21 #include "llvm/Object/ObjectFile.h"
22 #include "llvm/Object/SymbolicFile.h"
23 #include "llvm/Object/Wasm.h"
24 #include "llvm/Support/Endian.h"
25 #include "llvm/Support/Error.h"
26 #include "llvm/Support/ErrorHandling.h"
27 #include "llvm/Support/LEB128.h"
28 #include "llvm/Support/ScopedPrinter.h"
29 #include <algorithm>
30 #include <cassert>
31 #include <cstdint>
32 #include <cstring>
33 #include <system_error>
34 
35 #define DEBUG_TYPE "wasm-object"
36 
37 using namespace llvm;
38 using namespace object;
39 
print(raw_ostream & Out) const40 void WasmSymbol::print(raw_ostream &Out) const {
41   Out << "Name=" << Info.Name
42       << ", Kind=" << toString(wasm::WasmSymbolType(Info.Kind))
43       << ", Flags=" << Info.Flags;
44   if (!isTypeData()) {
45     Out << ", ElemIndex=" << Info.ElementIndex;
46   } else if (isDefined()) {
47     Out << ", Segment=" << Info.DataRef.Segment;
48     Out << ", Offset=" << Info.DataRef.Offset;
49     Out << ", Size=" << Info.DataRef.Size;
50   }
51 }
52 
53 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump() const54 LLVM_DUMP_METHOD void WasmSymbol::dump() const { print(dbgs()); }
55 #endif
56 
57 Expected<std::unique_ptr<WasmObjectFile>>
createWasmObjectFile(MemoryBufferRef Buffer)58 ObjectFile::createWasmObjectFile(MemoryBufferRef Buffer) {
59   Error Err = Error::success();
60   auto ObjectFile = std::make_unique<WasmObjectFile>(Buffer, Err);
61   if (Err)
62     return std::move(Err);
63 
64   return std::move(ObjectFile);
65 }
66 
67 #define VARINT7_MAX ((1 << 7) - 1)
68 #define VARINT7_MIN (-(1 << 7))
69 #define VARUINT7_MAX (1 << 7)
70 #define VARUINT1_MAX (1)
71 
readUint8(WasmObjectFile::ReadContext & Ctx)72 static uint8_t readUint8(WasmObjectFile::ReadContext &Ctx) {
73   if (Ctx.Ptr == Ctx.End)
74     report_fatal_error("EOF while reading uint8");
75   return *Ctx.Ptr++;
76 }
77 
readUint32(WasmObjectFile::ReadContext & Ctx)78 static uint32_t readUint32(WasmObjectFile::ReadContext &Ctx) {
79   if (Ctx.Ptr + 4 > Ctx.End)
80     report_fatal_error("EOF while reading uint32");
81   uint32_t Result = support::endian::read32le(Ctx.Ptr);
82   Ctx.Ptr += 4;
83   return Result;
84 }
85 
readFloat32(WasmObjectFile::ReadContext & Ctx)86 static int32_t readFloat32(WasmObjectFile::ReadContext &Ctx) {
87   if (Ctx.Ptr + 4 > Ctx.End)
88     report_fatal_error("EOF while reading float64");
89   int32_t Result = 0;
90   memcpy(&Result, Ctx.Ptr, sizeof(Result));
91   Ctx.Ptr += sizeof(Result);
92   return Result;
93 }
94 
readFloat64(WasmObjectFile::ReadContext & Ctx)95 static int64_t readFloat64(WasmObjectFile::ReadContext &Ctx) {
96   if (Ctx.Ptr + 8 > Ctx.End)
97     report_fatal_error("EOF while reading float64");
98   int64_t Result = 0;
99   memcpy(&Result, Ctx.Ptr, sizeof(Result));
100   Ctx.Ptr += sizeof(Result);
101   return Result;
102 }
103 
readULEB128(WasmObjectFile::ReadContext & Ctx)104 static uint64_t readULEB128(WasmObjectFile::ReadContext &Ctx) {
105   unsigned Count;
106   const char *Error = nullptr;
107   uint64_t Result = decodeULEB128(Ctx.Ptr, &Count, Ctx.End, &Error);
108   if (Error)
109     report_fatal_error(Error);
110   Ctx.Ptr += Count;
111   return Result;
112 }
113 
readString(WasmObjectFile::ReadContext & Ctx)114 static StringRef readString(WasmObjectFile::ReadContext &Ctx) {
115   uint32_t StringLen = readULEB128(Ctx);
116   if (Ctx.Ptr + StringLen > Ctx.End)
117     report_fatal_error("EOF while reading string");
118   StringRef Return =
119       StringRef(reinterpret_cast<const char *>(Ctx.Ptr), StringLen);
120   Ctx.Ptr += StringLen;
121   return Return;
122 }
123 
readLEB128(WasmObjectFile::ReadContext & Ctx)124 static int64_t readLEB128(WasmObjectFile::ReadContext &Ctx) {
125   unsigned Count;
126   const char *Error = nullptr;
127   uint64_t Result = decodeSLEB128(Ctx.Ptr, &Count, Ctx.End, &Error);
128   if (Error)
129     report_fatal_error(Error);
130   Ctx.Ptr += Count;
131   return Result;
132 }
133 
readVaruint1(WasmObjectFile::ReadContext & Ctx)134 static uint8_t readVaruint1(WasmObjectFile::ReadContext &Ctx) {
135   int64_t Result = readLEB128(Ctx);
136   if (Result > VARUINT1_MAX || Result < 0)
137     report_fatal_error("LEB is outside Varuint1 range");
138   return Result;
139 }
140 
readVarint32(WasmObjectFile::ReadContext & Ctx)141 static int32_t readVarint32(WasmObjectFile::ReadContext &Ctx) {
142   int64_t Result = readLEB128(Ctx);
143   if (Result > INT32_MAX || Result < INT32_MIN)
144     report_fatal_error("LEB is outside Varint32 range");
145   return Result;
146 }
147 
readVaruint32(WasmObjectFile::ReadContext & Ctx)148 static uint32_t readVaruint32(WasmObjectFile::ReadContext &Ctx) {
149   uint64_t Result = readULEB128(Ctx);
150   if (Result > UINT32_MAX)
151     report_fatal_error("LEB is outside Varuint32 range");
152   return Result;
153 }
154 
readVarint64(WasmObjectFile::ReadContext & Ctx)155 static int64_t readVarint64(WasmObjectFile::ReadContext &Ctx) {
156   return readLEB128(Ctx);
157 }
158 
readVaruint64(WasmObjectFile::ReadContext & Ctx)159 static uint64_t readVaruint64(WasmObjectFile::ReadContext &Ctx) {
160   return readULEB128(Ctx);
161 }
162 
readOpcode(WasmObjectFile::ReadContext & Ctx)163 static uint8_t readOpcode(WasmObjectFile::ReadContext &Ctx) {
164   return readUint8(Ctx);
165 }
166 
readInitExpr(wasm::WasmInitExpr & Expr,WasmObjectFile::ReadContext & Ctx)167 static Error readInitExpr(wasm::WasmInitExpr &Expr,
168                           WasmObjectFile::ReadContext &Ctx) {
169   Expr.Opcode = readOpcode(Ctx);
170 
171   switch (Expr.Opcode) {
172   case wasm::WASM_OPCODE_I32_CONST:
173     Expr.Value.Int32 = readVarint32(Ctx);
174     break;
175   case wasm::WASM_OPCODE_I64_CONST:
176     Expr.Value.Int64 = readVarint64(Ctx);
177     break;
178   case wasm::WASM_OPCODE_F32_CONST:
179     Expr.Value.Float32 = readFloat32(Ctx);
180     break;
181   case wasm::WASM_OPCODE_F64_CONST:
182     Expr.Value.Float64 = readFloat64(Ctx);
183     break;
184   case wasm::WASM_OPCODE_GLOBAL_GET:
185     Expr.Value.Global = readULEB128(Ctx);
186     break;
187   case wasm::WASM_OPCODE_REF_NULL: {
188     wasm::ValType Ty = static_cast<wasm::ValType>(readULEB128(Ctx));
189     if (Ty != wasm::ValType::EXTERNREF) {
190       return make_error<GenericBinaryError>("Invalid type for ref.null",
191                                             object_error::parse_failed);
192     }
193     break;
194   }
195   default:
196     return make_error<GenericBinaryError>("Invalid opcode in init_expr",
197                                           object_error::parse_failed);
198   }
199 
200   uint8_t EndOpcode = readOpcode(Ctx);
201   if (EndOpcode != wasm::WASM_OPCODE_END) {
202     return make_error<GenericBinaryError>("Invalid init_expr",
203                                           object_error::parse_failed);
204   }
205   return Error::success();
206 }
207 
readLimits(WasmObjectFile::ReadContext & Ctx)208 static wasm::WasmLimits readLimits(WasmObjectFile::ReadContext &Ctx) {
209   wasm::WasmLimits Result;
210   Result.Flags = readVaruint32(Ctx);
211   Result.Initial = readVaruint64(Ctx);
212   if (Result.Flags & wasm::WASM_LIMITS_FLAG_HAS_MAX)
213     Result.Maximum = readVaruint64(Ctx);
214   return Result;
215 }
216 
readTable(WasmObjectFile::ReadContext & Ctx)217 static wasm::WasmTable readTable(WasmObjectFile::ReadContext &Ctx) {
218   wasm::WasmTable Table;
219   Table.ElemType = readUint8(Ctx);
220   Table.Limits = readLimits(Ctx);
221   // The caller needs to set Table.Index field for Table
222   return Table;
223 }
224 
readSection(WasmSection & Section,WasmObjectFile::ReadContext & Ctx,WasmSectionOrderChecker & Checker)225 static Error readSection(WasmSection &Section, WasmObjectFile::ReadContext &Ctx,
226                          WasmSectionOrderChecker &Checker) {
227   Section.Offset = Ctx.Ptr - Ctx.Start;
228   Section.Type = readUint8(Ctx);
229   LLVM_DEBUG(dbgs() << "readSection type=" << Section.Type << "\n");
230   uint32_t Size = readVaruint32(Ctx);
231   if (Size == 0)
232     return make_error<StringError>("Zero length section",
233                                    object_error::parse_failed);
234   if (Ctx.Ptr + Size > Ctx.End)
235     return make_error<StringError>("Section too large",
236                                    object_error::parse_failed);
237   if (Section.Type == wasm::WASM_SEC_CUSTOM) {
238     WasmObjectFile::ReadContext SectionCtx;
239     SectionCtx.Start = Ctx.Ptr;
240     SectionCtx.Ptr = Ctx.Ptr;
241     SectionCtx.End = Ctx.Ptr + Size;
242 
243     Section.Name = readString(SectionCtx);
244 
245     uint32_t SectionNameSize = SectionCtx.Ptr - SectionCtx.Start;
246     Ctx.Ptr += SectionNameSize;
247     Size -= SectionNameSize;
248   }
249 
250   if (!Checker.isValidSectionOrder(Section.Type, Section.Name)) {
251     return make_error<StringError>("Out of order section type: " +
252                                        llvm::to_string(Section.Type),
253                                    object_error::parse_failed);
254   }
255 
256   Section.Content = ArrayRef<uint8_t>(Ctx.Ptr, Size);
257   Ctx.Ptr += Size;
258   return Error::success();
259 }
260 
WasmObjectFile(MemoryBufferRef Buffer,Error & Err)261 WasmObjectFile::WasmObjectFile(MemoryBufferRef Buffer, Error &Err)
262     : ObjectFile(Binary::ID_Wasm, Buffer) {
263   ErrorAsOutParameter ErrAsOutParam(&Err);
264   Header.Magic = getData().substr(0, 4);
265   if (Header.Magic != StringRef("\0asm", 4)) {
266     Err =
267         make_error<StringError>("Bad magic number", object_error::parse_failed);
268     return;
269   }
270 
271   ReadContext Ctx;
272   Ctx.Start = getData().bytes_begin();
273   Ctx.Ptr = Ctx.Start + 4;
274   Ctx.End = Ctx.Start + getData().size();
275 
276   if (Ctx.Ptr + 4 > Ctx.End) {
277     Err = make_error<StringError>("Missing version number",
278                                   object_error::parse_failed);
279     return;
280   }
281 
282   Header.Version = readUint32(Ctx);
283   if (Header.Version != wasm::WasmVersion) {
284     Err = make_error<StringError>("Bad version number",
285                                   object_error::parse_failed);
286     return;
287   }
288 
289   WasmSection Sec;
290   WasmSectionOrderChecker Checker;
291   while (Ctx.Ptr < Ctx.End) {
292     if ((Err = readSection(Sec, Ctx, Checker)))
293       return;
294     if ((Err = parseSection(Sec)))
295       return;
296 
297     Sections.push_back(Sec);
298   }
299 }
300 
parseSection(WasmSection & Sec)301 Error WasmObjectFile::parseSection(WasmSection &Sec) {
302   ReadContext Ctx;
303   Ctx.Start = Sec.Content.data();
304   Ctx.End = Ctx.Start + Sec.Content.size();
305   Ctx.Ptr = Ctx.Start;
306   switch (Sec.Type) {
307   case wasm::WASM_SEC_CUSTOM:
308     return parseCustomSection(Sec, Ctx);
309   case wasm::WASM_SEC_TYPE:
310     return parseTypeSection(Ctx);
311   case wasm::WASM_SEC_IMPORT:
312     return parseImportSection(Ctx);
313   case wasm::WASM_SEC_FUNCTION:
314     return parseFunctionSection(Ctx);
315   case wasm::WASM_SEC_TABLE:
316     return parseTableSection(Ctx);
317   case wasm::WASM_SEC_MEMORY:
318     return parseMemorySection(Ctx);
319   case wasm::WASM_SEC_EVENT:
320     return parseEventSection(Ctx);
321   case wasm::WASM_SEC_GLOBAL:
322     return parseGlobalSection(Ctx);
323   case wasm::WASM_SEC_EXPORT:
324     return parseExportSection(Ctx);
325   case wasm::WASM_SEC_START:
326     return parseStartSection(Ctx);
327   case wasm::WASM_SEC_ELEM:
328     return parseElemSection(Ctx);
329   case wasm::WASM_SEC_CODE:
330     return parseCodeSection(Ctx);
331   case wasm::WASM_SEC_DATA:
332     return parseDataSection(Ctx);
333   case wasm::WASM_SEC_DATACOUNT:
334     return parseDataCountSection(Ctx);
335   default:
336     return make_error<GenericBinaryError>(
337         "Invalid section type: " + Twine(Sec.Type), object_error::parse_failed);
338   }
339 }
340 
parseDylinkSection(ReadContext & Ctx)341 Error WasmObjectFile::parseDylinkSection(ReadContext &Ctx) {
342   // See https://github.com/WebAssembly/tool-conventions/blob/master/DynamicLinking.md
343   HasDylinkSection = true;
344   DylinkInfo.MemorySize = readVaruint32(Ctx);
345   DylinkInfo.MemoryAlignment = readVaruint32(Ctx);
346   DylinkInfo.TableSize = readVaruint32(Ctx);
347   DylinkInfo.TableAlignment = readVaruint32(Ctx);
348   uint32_t Count = readVaruint32(Ctx);
349   while (Count--) {
350     DylinkInfo.Needed.push_back(readString(Ctx));
351   }
352   if (Ctx.Ptr != Ctx.End)
353     return make_error<GenericBinaryError>("dylink section ended prematurely",
354                                           object_error::parse_failed);
355   return Error::success();
356 }
357 
parseNameSection(ReadContext & Ctx)358 Error WasmObjectFile::parseNameSection(ReadContext &Ctx) {
359   llvm::DenseSet<uint64_t> Seen;
360   if (FunctionTypes.size() && !SeenCodeSection) {
361     return make_error<GenericBinaryError>("Names must come after code section",
362                                           object_error::parse_failed);
363   }
364 
365   while (Ctx.Ptr < Ctx.End) {
366     uint8_t Type = readUint8(Ctx);
367     uint32_t Size = readVaruint32(Ctx);
368     const uint8_t *SubSectionEnd = Ctx.Ptr + Size;
369     switch (Type) {
370     case wasm::WASM_NAMES_FUNCTION: {
371       uint32_t Count = readVaruint32(Ctx);
372       while (Count--) {
373         uint32_t Index = readVaruint32(Ctx);
374         if (!Seen.insert(Index).second)
375           return make_error<GenericBinaryError>("Function named more than once",
376                                                 object_error::parse_failed);
377         StringRef Name = readString(Ctx);
378         if (!isValidFunctionIndex(Index) || Name.empty())
379           return make_error<GenericBinaryError>("Invalid name entry",
380                                                 object_error::parse_failed);
381         DebugNames.push_back(wasm::WasmFunctionName{Index, Name});
382         if (isDefinedFunctionIndex(Index))
383           getDefinedFunction(Index).DebugName = Name;
384       }
385       break;
386     }
387     // Ignore local names for now
388     case wasm::WASM_NAMES_LOCAL:
389     default:
390       Ctx.Ptr += Size;
391       break;
392     }
393     if (Ctx.Ptr != SubSectionEnd)
394       return make_error<GenericBinaryError>(
395           "Name sub-section ended prematurely", object_error::parse_failed);
396   }
397 
398   if (Ctx.Ptr != Ctx.End)
399     return make_error<GenericBinaryError>("Name section ended prematurely",
400                                           object_error::parse_failed);
401   return Error::success();
402 }
403 
parseLinkingSection(ReadContext & Ctx)404 Error WasmObjectFile::parseLinkingSection(ReadContext &Ctx) {
405   HasLinkingSection = true;
406   if (FunctionTypes.size() && !SeenCodeSection) {
407     return make_error<GenericBinaryError>(
408         "Linking data must come after code section",
409         object_error::parse_failed);
410   }
411 
412   LinkingData.Version = readVaruint32(Ctx);
413   if (LinkingData.Version != wasm::WasmMetadataVersion) {
414     return make_error<GenericBinaryError>(
415         "Unexpected metadata version: " + Twine(LinkingData.Version) +
416             " (Expected: " + Twine(wasm::WasmMetadataVersion) + ")",
417         object_error::parse_failed);
418   }
419 
420   const uint8_t *OrigEnd = Ctx.End;
421   while (Ctx.Ptr < OrigEnd) {
422     Ctx.End = OrigEnd;
423     uint8_t Type = readUint8(Ctx);
424     uint32_t Size = readVaruint32(Ctx);
425     LLVM_DEBUG(dbgs() << "readSubsection type=" << int(Type) << " size=" << Size
426                       << "\n");
427     Ctx.End = Ctx.Ptr + Size;
428     switch (Type) {
429     case wasm::WASM_SYMBOL_TABLE:
430       if (Error Err = parseLinkingSectionSymtab(Ctx))
431         return Err;
432       break;
433     case wasm::WASM_SEGMENT_INFO: {
434       uint32_t Count = readVaruint32(Ctx);
435       if (Count > DataSegments.size())
436         return make_error<GenericBinaryError>("Too many segment names",
437                                               object_error::parse_failed);
438       for (uint32_t I = 0; I < Count; I++) {
439         DataSegments[I].Data.Name = readString(Ctx);
440         DataSegments[I].Data.Alignment = readVaruint32(Ctx);
441         DataSegments[I].Data.LinkerFlags = readVaruint32(Ctx);
442       }
443       break;
444     }
445     case wasm::WASM_INIT_FUNCS: {
446       uint32_t Count = readVaruint32(Ctx);
447       LinkingData.InitFunctions.reserve(Count);
448       for (uint32_t I = 0; I < Count; I++) {
449         wasm::WasmInitFunc Init;
450         Init.Priority = readVaruint32(Ctx);
451         Init.Symbol = readVaruint32(Ctx);
452         if (!isValidFunctionSymbol(Init.Symbol))
453           return make_error<GenericBinaryError>("Invalid function symbol: " +
454                                                     Twine(Init.Symbol),
455                                                 object_error::parse_failed);
456         LinkingData.InitFunctions.emplace_back(Init);
457       }
458       break;
459     }
460     case wasm::WASM_COMDAT_INFO:
461       if (Error Err = parseLinkingSectionComdat(Ctx))
462         return Err;
463       break;
464     default:
465       Ctx.Ptr += Size;
466       break;
467     }
468     if (Ctx.Ptr != Ctx.End)
469       return make_error<GenericBinaryError>(
470           "Linking sub-section ended prematurely", object_error::parse_failed);
471   }
472   if (Ctx.Ptr != OrigEnd)
473     return make_error<GenericBinaryError>("Linking section ended prematurely",
474                                           object_error::parse_failed);
475   return Error::success();
476 }
477 
parseLinkingSectionSymtab(ReadContext & Ctx)478 Error WasmObjectFile::parseLinkingSectionSymtab(ReadContext &Ctx) {
479   uint32_t Count = readVaruint32(Ctx);
480   LinkingData.SymbolTable.reserve(Count);
481   Symbols.reserve(Count);
482   StringSet<> SymbolNames;
483 
484   std::vector<wasm::WasmImport *> ImportedGlobals;
485   std::vector<wasm::WasmImport *> ImportedFunctions;
486   std::vector<wasm::WasmImport *> ImportedEvents;
487   ImportedGlobals.reserve(Imports.size());
488   ImportedFunctions.reserve(Imports.size());
489   ImportedEvents.reserve(Imports.size());
490   for (auto &I : Imports) {
491     if (I.Kind == wasm::WASM_EXTERNAL_FUNCTION)
492       ImportedFunctions.emplace_back(&I);
493     else if (I.Kind == wasm::WASM_EXTERNAL_GLOBAL)
494       ImportedGlobals.emplace_back(&I);
495     else if (I.Kind == wasm::WASM_EXTERNAL_EVENT)
496       ImportedEvents.emplace_back(&I);
497   }
498 
499   while (Count--) {
500     wasm::WasmSymbolInfo Info;
501     const wasm::WasmSignature *Signature = nullptr;
502     const wasm::WasmGlobalType *GlobalType = nullptr;
503     uint8_t TableType = 0;
504     const wasm::WasmEventType *EventType = nullptr;
505 
506     Info.Kind = readUint8(Ctx);
507     Info.Flags = readVaruint32(Ctx);
508     bool IsDefined = (Info.Flags & wasm::WASM_SYMBOL_UNDEFINED) == 0;
509 
510     switch (Info.Kind) {
511     case wasm::WASM_SYMBOL_TYPE_FUNCTION:
512       Info.ElementIndex = readVaruint32(Ctx);
513       if (!isValidFunctionIndex(Info.ElementIndex) ||
514           IsDefined != isDefinedFunctionIndex(Info.ElementIndex))
515         return make_error<GenericBinaryError>("invalid function symbol index",
516                                               object_error::parse_failed);
517       if (IsDefined) {
518         Info.Name = readString(Ctx);
519         unsigned FuncIndex = Info.ElementIndex - NumImportedFunctions;
520         Signature = &Signatures[FunctionTypes[FuncIndex]];
521         wasm::WasmFunction &Function = Functions[FuncIndex];
522         if (Function.SymbolName.empty())
523           Function.SymbolName = Info.Name;
524       } else {
525         wasm::WasmImport &Import = *ImportedFunctions[Info.ElementIndex];
526         if ((Info.Flags & wasm::WASM_SYMBOL_EXPLICIT_NAME) != 0) {
527           Info.Name = readString(Ctx);
528           Info.ImportName = Import.Field;
529         } else {
530           Info.Name = Import.Field;
531         }
532         Signature = &Signatures[Import.SigIndex];
533         if (!Import.Module.empty()) {
534           Info.ImportModule = Import.Module;
535         }
536       }
537       break;
538 
539     case wasm::WASM_SYMBOL_TYPE_GLOBAL:
540       Info.ElementIndex = readVaruint32(Ctx);
541       if (!isValidGlobalIndex(Info.ElementIndex) ||
542           IsDefined != isDefinedGlobalIndex(Info.ElementIndex))
543         return make_error<GenericBinaryError>("invalid global symbol index",
544                                               object_error::parse_failed);
545       if (!IsDefined && (Info.Flags & wasm::WASM_SYMBOL_BINDING_MASK) ==
546                             wasm::WASM_SYMBOL_BINDING_WEAK)
547         return make_error<GenericBinaryError>("undefined weak global symbol",
548                                               object_error::parse_failed);
549       if (IsDefined) {
550         Info.Name = readString(Ctx);
551         unsigned GlobalIndex = Info.ElementIndex - NumImportedGlobals;
552         wasm::WasmGlobal &Global = Globals[GlobalIndex];
553         GlobalType = &Global.Type;
554         if (Global.SymbolName.empty())
555           Global.SymbolName = Info.Name;
556       } else {
557         wasm::WasmImport &Import = *ImportedGlobals[Info.ElementIndex];
558         if ((Info.Flags & wasm::WASM_SYMBOL_EXPLICIT_NAME) != 0) {
559           Info.Name = readString(Ctx);
560           Info.ImportName = Import.Field;
561         } else {
562           Info.Name = Import.Field;
563         }
564         GlobalType = &Import.Global;
565         Info.ImportName = Import.Field;
566         if (!Import.Module.empty()) {
567           Info.ImportModule = Import.Module;
568         }
569       }
570       break;
571 
572     case wasm::WASM_SYMBOL_TYPE_TABLE:
573       Info.ElementIndex = readVaruint32(Ctx);
574       if (!isValidTableIndex(Info.ElementIndex) ||
575           IsDefined != isDefinedTableIndex(Info.ElementIndex))
576         return make_error<GenericBinaryError>("invalid table symbol index",
577                                               object_error::parse_failed);
578       if (!IsDefined && (Info.Flags & wasm::WASM_SYMBOL_BINDING_MASK) ==
579                             wasm::WASM_SYMBOL_BINDING_WEAK)
580         return make_error<GenericBinaryError>("undefined weak table symbol",
581                                               object_error::parse_failed);
582       if (IsDefined) {
583         Info.Name = readString(Ctx);
584         unsigned TableIndex = Info.ElementIndex - NumImportedTables;
585         wasm::WasmTable &Table = Tables[TableIndex];
586         TableType = Table.ElemType;
587       } else {
588         return make_error<GenericBinaryError>("undefined table symbol",
589                                               object_error::parse_failed);
590       }
591       break;
592 
593     case wasm::WASM_SYMBOL_TYPE_DATA:
594       Info.Name = readString(Ctx);
595       if (IsDefined) {
596         auto Index = readVaruint32(Ctx);
597         if (Index >= DataSegments.size())
598           return make_error<GenericBinaryError>("invalid data symbol index",
599                                                 object_error::parse_failed);
600         auto Offset = readVaruint64(Ctx);
601         auto Size = readVaruint64(Ctx);
602         if (Offset + Size > DataSegments[Index].Data.Content.size())
603           return make_error<GenericBinaryError>("invalid data symbol offset",
604                                                 object_error::parse_failed);
605         Info.DataRef = wasm::WasmDataReference{Index, Offset, Size};
606       }
607       break;
608 
609     case wasm::WASM_SYMBOL_TYPE_SECTION: {
610       if ((Info.Flags & wasm::WASM_SYMBOL_BINDING_MASK) !=
611           wasm::WASM_SYMBOL_BINDING_LOCAL)
612         return make_error<GenericBinaryError>(
613             "Section symbols must have local binding",
614             object_error::parse_failed);
615       Info.ElementIndex = readVaruint32(Ctx);
616       // Use somewhat unique section name as symbol name.
617       StringRef SectionName = Sections[Info.ElementIndex].Name;
618       Info.Name = SectionName;
619       break;
620     }
621 
622     case wasm::WASM_SYMBOL_TYPE_EVENT: {
623       Info.ElementIndex = readVaruint32(Ctx);
624       if (!isValidEventIndex(Info.ElementIndex) ||
625           IsDefined != isDefinedEventIndex(Info.ElementIndex))
626         return make_error<GenericBinaryError>("invalid event symbol index",
627                                               object_error::parse_failed);
628       if (!IsDefined && (Info.Flags & wasm::WASM_SYMBOL_BINDING_MASK) ==
629                             wasm::WASM_SYMBOL_BINDING_WEAK)
630         return make_error<GenericBinaryError>("undefined weak global symbol",
631                                               object_error::parse_failed);
632       if (IsDefined) {
633         Info.Name = readString(Ctx);
634         unsigned EventIndex = Info.ElementIndex - NumImportedEvents;
635         wasm::WasmEvent &Event = Events[EventIndex];
636         Signature = &Signatures[Event.Type.SigIndex];
637         EventType = &Event.Type;
638         if (Event.SymbolName.empty())
639           Event.SymbolName = Info.Name;
640 
641       } else {
642         wasm::WasmImport &Import = *ImportedEvents[Info.ElementIndex];
643         if ((Info.Flags & wasm::WASM_SYMBOL_EXPLICIT_NAME) != 0) {
644           Info.Name = readString(Ctx);
645           Info.ImportName = Import.Field;
646         } else {
647           Info.Name = Import.Field;
648         }
649         EventType = &Import.Event;
650         Signature = &Signatures[EventType->SigIndex];
651         if (!Import.Module.empty()) {
652           Info.ImportModule = Import.Module;
653         }
654       }
655       break;
656     }
657 
658     default:
659       return make_error<GenericBinaryError>("Invalid symbol type",
660                                             object_error::parse_failed);
661     }
662 
663     if ((Info.Flags & wasm::WASM_SYMBOL_BINDING_MASK) !=
664             wasm::WASM_SYMBOL_BINDING_LOCAL &&
665         !SymbolNames.insert(Info.Name).second)
666       return make_error<GenericBinaryError>("Duplicate symbol name " +
667                                                 Twine(Info.Name),
668                                             object_error::parse_failed);
669     LinkingData.SymbolTable.emplace_back(Info);
670     Symbols.emplace_back(LinkingData.SymbolTable.back(), GlobalType, TableType,
671                          EventType, Signature);
672     LLVM_DEBUG(dbgs() << "Adding symbol: " << Symbols.back() << "\n");
673   }
674 
675   return Error::success();
676 }
677 
parseLinkingSectionComdat(ReadContext & Ctx)678 Error WasmObjectFile::parseLinkingSectionComdat(ReadContext &Ctx) {
679   uint32_t ComdatCount = readVaruint32(Ctx);
680   StringSet<> ComdatSet;
681   for (unsigned ComdatIndex = 0; ComdatIndex < ComdatCount; ++ComdatIndex) {
682     StringRef Name = readString(Ctx);
683     if (Name.empty() || !ComdatSet.insert(Name).second)
684       return make_error<GenericBinaryError>("Bad/duplicate COMDAT name " +
685                                                 Twine(Name),
686                                             object_error::parse_failed);
687     LinkingData.Comdats.emplace_back(Name);
688     uint32_t Flags = readVaruint32(Ctx);
689     if (Flags != 0)
690       return make_error<GenericBinaryError>("Unsupported COMDAT flags",
691                                             object_error::parse_failed);
692 
693     uint32_t EntryCount = readVaruint32(Ctx);
694     while (EntryCount--) {
695       unsigned Kind = readVaruint32(Ctx);
696       unsigned Index = readVaruint32(Ctx);
697       switch (Kind) {
698       default:
699         return make_error<GenericBinaryError>("Invalid COMDAT entry type",
700                                               object_error::parse_failed);
701       case wasm::WASM_COMDAT_DATA:
702         if (Index >= DataSegments.size())
703           return make_error<GenericBinaryError>(
704               "COMDAT data index out of range", object_error::parse_failed);
705         if (DataSegments[Index].Data.Comdat != UINT32_MAX)
706           return make_error<GenericBinaryError>("Data segment in two COMDATs",
707                                                 object_error::parse_failed);
708         DataSegments[Index].Data.Comdat = ComdatIndex;
709         break;
710       case wasm::WASM_COMDAT_FUNCTION:
711         if (!isDefinedFunctionIndex(Index))
712           return make_error<GenericBinaryError>(
713               "COMDAT function index out of range", object_error::parse_failed);
714         if (getDefinedFunction(Index).Comdat != UINT32_MAX)
715           return make_error<GenericBinaryError>("Function in two COMDATs",
716                                                 object_error::parse_failed);
717         getDefinedFunction(Index).Comdat = ComdatIndex;
718         break;
719       }
720     }
721   }
722   return Error::success();
723 }
724 
parseProducersSection(ReadContext & Ctx)725 Error WasmObjectFile::parseProducersSection(ReadContext &Ctx) {
726   llvm::SmallSet<StringRef, 3> FieldsSeen;
727   uint32_t Fields = readVaruint32(Ctx);
728   for (size_t I = 0; I < Fields; ++I) {
729     StringRef FieldName = readString(Ctx);
730     if (!FieldsSeen.insert(FieldName).second)
731       return make_error<GenericBinaryError>(
732           "Producers section does not have unique fields",
733           object_error::parse_failed);
734     std::vector<std::pair<std::string, std::string>> *ProducerVec = nullptr;
735     if (FieldName == "language") {
736       ProducerVec = &ProducerInfo.Languages;
737     } else if (FieldName == "processed-by") {
738       ProducerVec = &ProducerInfo.Tools;
739     } else if (FieldName == "sdk") {
740       ProducerVec = &ProducerInfo.SDKs;
741     } else {
742       return make_error<GenericBinaryError>(
743           "Producers section field is not named one of language, processed-by, "
744           "or sdk",
745           object_error::parse_failed);
746     }
747     uint32_t ValueCount = readVaruint32(Ctx);
748     llvm::SmallSet<StringRef, 8> ProducersSeen;
749     for (size_t J = 0; J < ValueCount; ++J) {
750       StringRef Name = readString(Ctx);
751       StringRef Version = readString(Ctx);
752       if (!ProducersSeen.insert(Name).second) {
753         return make_error<GenericBinaryError>(
754             "Producers section contains repeated producer",
755             object_error::parse_failed);
756       }
757       ProducerVec->emplace_back(std::string(Name), std::string(Version));
758     }
759   }
760   if (Ctx.Ptr != Ctx.End)
761     return make_error<GenericBinaryError>("Producers section ended prematurely",
762                                           object_error::parse_failed);
763   return Error::success();
764 }
765 
parseTargetFeaturesSection(ReadContext & Ctx)766 Error WasmObjectFile::parseTargetFeaturesSection(ReadContext &Ctx) {
767   llvm::SmallSet<std::string, 8> FeaturesSeen;
768   uint32_t FeatureCount = readVaruint32(Ctx);
769   for (size_t I = 0; I < FeatureCount; ++I) {
770     wasm::WasmFeatureEntry Feature;
771     Feature.Prefix = readUint8(Ctx);
772     switch (Feature.Prefix) {
773     case wasm::WASM_FEATURE_PREFIX_USED:
774     case wasm::WASM_FEATURE_PREFIX_REQUIRED:
775     case wasm::WASM_FEATURE_PREFIX_DISALLOWED:
776       break;
777     default:
778       return make_error<GenericBinaryError>("Unknown feature policy prefix",
779                                             object_error::parse_failed);
780     }
781     Feature.Name = std::string(readString(Ctx));
782     if (!FeaturesSeen.insert(Feature.Name).second)
783       return make_error<GenericBinaryError>(
784           "Target features section contains repeated feature \"" +
785               Feature.Name + "\"",
786           object_error::parse_failed);
787     TargetFeatures.push_back(Feature);
788   }
789   if (Ctx.Ptr != Ctx.End)
790     return make_error<GenericBinaryError>(
791         "Target features section ended prematurely",
792         object_error::parse_failed);
793   return Error::success();
794 }
795 
parseRelocSection(StringRef Name,ReadContext & Ctx)796 Error WasmObjectFile::parseRelocSection(StringRef Name, ReadContext &Ctx) {
797   uint32_t SectionIndex = readVaruint32(Ctx);
798   if (SectionIndex >= Sections.size())
799     return make_error<GenericBinaryError>("Invalid section index",
800                                           object_error::parse_failed);
801   WasmSection &Section = Sections[SectionIndex];
802   uint32_t RelocCount = readVaruint32(Ctx);
803   uint32_t EndOffset = Section.Content.size();
804   uint32_t PreviousOffset = 0;
805   while (RelocCount--) {
806     wasm::WasmRelocation Reloc = {};
807     Reloc.Type = readVaruint32(Ctx);
808     Reloc.Offset = readVaruint32(Ctx);
809     if (Reloc.Offset < PreviousOffset)
810       return make_error<GenericBinaryError>("Relocations not in offset order",
811                                             object_error::parse_failed);
812     PreviousOffset = Reloc.Offset;
813     Reloc.Index = readVaruint32(Ctx);
814     switch (Reloc.Type) {
815     case wasm::R_WASM_FUNCTION_INDEX_LEB:
816     case wasm::R_WASM_TABLE_INDEX_SLEB:
817     case wasm::R_WASM_TABLE_INDEX_SLEB64:
818     case wasm::R_WASM_TABLE_INDEX_I32:
819     case wasm::R_WASM_TABLE_INDEX_I64:
820     case wasm::R_WASM_TABLE_INDEX_REL_SLEB:
821       if (!isValidFunctionSymbol(Reloc.Index))
822         return make_error<GenericBinaryError>("Bad relocation function index",
823                                               object_error::parse_failed);
824       break;
825     case wasm::R_WASM_TABLE_NUMBER_LEB:
826       if (!isValidTableSymbol(Reloc.Index))
827         return make_error<GenericBinaryError>("Bad relocation table index",
828                                               object_error::parse_failed);
829       break;
830     case wasm::R_WASM_TYPE_INDEX_LEB:
831       if (Reloc.Index >= Signatures.size())
832         return make_error<GenericBinaryError>("Bad relocation type index",
833                                               object_error::parse_failed);
834       break;
835     case wasm::R_WASM_GLOBAL_INDEX_LEB:
836       // R_WASM_GLOBAL_INDEX_LEB are can be used against function and data
837       // symbols to refer to their GOT entries.
838       if (!isValidGlobalSymbol(Reloc.Index) &&
839           !isValidDataSymbol(Reloc.Index) &&
840           !isValidFunctionSymbol(Reloc.Index))
841         return make_error<GenericBinaryError>("Bad relocation global index",
842                                               object_error::parse_failed);
843       break;
844     case wasm::R_WASM_GLOBAL_INDEX_I32:
845       if (!isValidGlobalSymbol(Reloc.Index))
846         return make_error<GenericBinaryError>("Bad relocation global index",
847                                               object_error::parse_failed);
848       break;
849     case wasm::R_WASM_EVENT_INDEX_LEB:
850       if (!isValidEventSymbol(Reloc.Index))
851         return make_error<GenericBinaryError>("Bad relocation event index",
852                                               object_error::parse_failed);
853       break;
854     case wasm::R_WASM_MEMORY_ADDR_LEB:
855     case wasm::R_WASM_MEMORY_ADDR_SLEB:
856     case wasm::R_WASM_MEMORY_ADDR_I32:
857     case wasm::R_WASM_MEMORY_ADDR_REL_SLEB:
858       if (!isValidDataSymbol(Reloc.Index))
859         return make_error<GenericBinaryError>("Bad relocation data index",
860                                               object_error::parse_failed);
861       Reloc.Addend = readVarint32(Ctx);
862       break;
863     case wasm::R_WASM_MEMORY_ADDR_LEB64:
864     case wasm::R_WASM_MEMORY_ADDR_SLEB64:
865     case wasm::R_WASM_MEMORY_ADDR_I64:
866     case wasm::R_WASM_MEMORY_ADDR_REL_SLEB64:
867       if (!isValidDataSymbol(Reloc.Index))
868         return make_error<GenericBinaryError>("Bad relocation data index",
869                                               object_error::parse_failed);
870       Reloc.Addend = readVarint64(Ctx);
871       break;
872     case wasm::R_WASM_FUNCTION_OFFSET_I32:
873       if (!isValidFunctionSymbol(Reloc.Index))
874         return make_error<GenericBinaryError>("Bad relocation function index",
875                                               object_error::parse_failed);
876       Reloc.Addend = readVarint32(Ctx);
877       break;
878     case wasm::R_WASM_SECTION_OFFSET_I32:
879       if (!isValidSectionSymbol(Reloc.Index))
880         return make_error<GenericBinaryError>("Bad relocation section index",
881                                               object_error::parse_failed);
882       Reloc.Addend = readVarint32(Ctx);
883       break;
884     default:
885       return make_error<GenericBinaryError>("Bad relocation type: " +
886                                                 Twine(Reloc.Type),
887                                             object_error::parse_failed);
888     }
889 
890     // Relocations must fit inside the section, and must appear in order.  They
891     // also shouldn't overlap a function/element boundary, but we don't bother
892     // to check that.
893     uint64_t Size = 5;
894     if (Reloc.Type == wasm::R_WASM_MEMORY_ADDR_LEB64 ||
895         Reloc.Type == wasm::R_WASM_MEMORY_ADDR_SLEB64 ||
896         Reloc.Type == wasm::R_WASM_MEMORY_ADDR_REL_SLEB64)
897       Size = 10;
898     if (Reloc.Type == wasm::R_WASM_TABLE_INDEX_I32 ||
899         Reloc.Type == wasm::R_WASM_MEMORY_ADDR_I32 ||
900         Reloc.Type == wasm::R_WASM_SECTION_OFFSET_I32 ||
901         Reloc.Type == wasm::R_WASM_FUNCTION_OFFSET_I32 ||
902         Reloc.Type == wasm::R_WASM_GLOBAL_INDEX_I32)
903       Size = 4;
904     if (Reloc.Type == wasm::R_WASM_TABLE_INDEX_I64 ||
905         Reloc.Type == wasm::R_WASM_MEMORY_ADDR_I64)
906       Size = 8;
907     if (Reloc.Offset + Size > EndOffset)
908       return make_error<GenericBinaryError>("Bad relocation offset",
909                                             object_error::parse_failed);
910 
911     Section.Relocations.push_back(Reloc);
912   }
913   if (Ctx.Ptr != Ctx.End)
914     return make_error<GenericBinaryError>("Reloc section ended prematurely",
915                                           object_error::parse_failed);
916   return Error::success();
917 }
918 
parseCustomSection(WasmSection & Sec,ReadContext & Ctx)919 Error WasmObjectFile::parseCustomSection(WasmSection &Sec, ReadContext &Ctx) {
920   if (Sec.Name == "dylink") {
921     if (Error Err = parseDylinkSection(Ctx))
922       return Err;
923   } else if (Sec.Name == "name") {
924     if (Error Err = parseNameSection(Ctx))
925       return Err;
926   } else if (Sec.Name == "linking") {
927     if (Error Err = parseLinkingSection(Ctx))
928       return Err;
929   } else if (Sec.Name == "producers") {
930     if (Error Err = parseProducersSection(Ctx))
931       return Err;
932   } else if (Sec.Name == "target_features") {
933     if (Error Err = parseTargetFeaturesSection(Ctx))
934       return Err;
935   } else if (Sec.Name.startswith("reloc.")) {
936     if (Error Err = parseRelocSection(Sec.Name, Ctx))
937       return Err;
938   }
939   return Error::success();
940 }
941 
parseTypeSection(ReadContext & Ctx)942 Error WasmObjectFile::parseTypeSection(ReadContext &Ctx) {
943   uint32_t Count = readVaruint32(Ctx);
944   Signatures.reserve(Count);
945   while (Count--) {
946     wasm::WasmSignature Sig;
947     uint8_t Form = readUint8(Ctx);
948     if (Form != wasm::WASM_TYPE_FUNC) {
949       return make_error<GenericBinaryError>("Invalid signature type",
950                                             object_error::parse_failed);
951     }
952     uint32_t ParamCount = readVaruint32(Ctx);
953     Sig.Params.reserve(ParamCount);
954     while (ParamCount--) {
955       uint32_t ParamType = readUint8(Ctx);
956       Sig.Params.push_back(wasm::ValType(ParamType));
957     }
958     uint32_t ReturnCount = readVaruint32(Ctx);
959     while (ReturnCount--) {
960       uint32_t ReturnType = readUint8(Ctx);
961       Sig.Returns.push_back(wasm::ValType(ReturnType));
962     }
963     Signatures.push_back(std::move(Sig));
964   }
965   if (Ctx.Ptr != Ctx.End)
966     return make_error<GenericBinaryError>("Type section ended prematurely",
967                                           object_error::parse_failed);
968   return Error::success();
969 }
970 
parseImportSection(ReadContext & Ctx)971 Error WasmObjectFile::parseImportSection(ReadContext &Ctx) {
972   uint32_t Count = readVaruint32(Ctx);
973   Imports.reserve(Count);
974   for (uint32_t I = 0; I < Count; I++) {
975     wasm::WasmImport Im;
976     Im.Module = readString(Ctx);
977     Im.Field = readString(Ctx);
978     Im.Kind = readUint8(Ctx);
979     switch (Im.Kind) {
980     case wasm::WASM_EXTERNAL_FUNCTION:
981       NumImportedFunctions++;
982       Im.SigIndex = readVaruint32(Ctx);
983       break;
984     case wasm::WASM_EXTERNAL_GLOBAL:
985       NumImportedGlobals++;
986       Im.Global.Type = readUint8(Ctx);
987       Im.Global.Mutable = readVaruint1(Ctx);
988       break;
989     case wasm::WASM_EXTERNAL_MEMORY:
990       Im.Memory = readLimits(Ctx);
991       if (Im.Memory.Flags & wasm::WASM_LIMITS_FLAG_IS_64)
992         HasMemory64 = true;
993       break;
994     case wasm::WASM_EXTERNAL_TABLE: {
995       Im.Table = readTable(Ctx);
996       Im.Table.Index = NumImportedTables + Tables.size();
997       NumImportedTables++;
998       auto ElemType = Im.Table.ElemType;
999       if (ElemType != wasm::WASM_TYPE_FUNCREF &&
1000           ElemType != wasm::WASM_TYPE_EXTERNREF)
1001         return make_error<GenericBinaryError>("Invalid table element type",
1002                                               object_error::parse_failed);
1003       break;
1004     }
1005     case wasm::WASM_EXTERNAL_EVENT:
1006       NumImportedEvents++;
1007       Im.Event.Attribute = readVarint32(Ctx);
1008       Im.Event.SigIndex = readVarint32(Ctx);
1009       break;
1010     default:
1011       return make_error<GenericBinaryError>("Unexpected import kind",
1012                                             object_error::parse_failed);
1013     }
1014     Imports.push_back(Im);
1015   }
1016   if (Ctx.Ptr != Ctx.End)
1017     return make_error<GenericBinaryError>("Import section ended prematurely",
1018                                           object_error::parse_failed);
1019   return Error::success();
1020 }
1021 
parseFunctionSection(ReadContext & Ctx)1022 Error WasmObjectFile::parseFunctionSection(ReadContext &Ctx) {
1023   uint32_t Count = readVaruint32(Ctx);
1024   FunctionTypes.reserve(Count);
1025   Functions.resize(Count);
1026   uint32_t NumTypes = Signatures.size();
1027   while (Count--) {
1028     uint32_t Type = readVaruint32(Ctx);
1029     if (Type >= NumTypes)
1030       return make_error<GenericBinaryError>("Invalid function type",
1031                                             object_error::parse_failed);
1032     FunctionTypes.push_back(Type);
1033   }
1034   if (Ctx.Ptr != Ctx.End)
1035     return make_error<GenericBinaryError>("Function section ended prematurely",
1036                                           object_error::parse_failed);
1037   return Error::success();
1038 }
1039 
parseTableSection(ReadContext & Ctx)1040 Error WasmObjectFile::parseTableSection(ReadContext &Ctx) {
1041   uint32_t Count = readVaruint32(Ctx);
1042   Tables.reserve(Count);
1043   while (Count--) {
1044     wasm::WasmTable T = readTable(Ctx);
1045     T.Index = NumImportedTables + Tables.size();
1046     Tables.push_back(T);
1047     auto ElemType = Tables.back().ElemType;
1048     if (ElemType != wasm::WASM_TYPE_FUNCREF &&
1049         ElemType != wasm::WASM_TYPE_EXTERNREF) {
1050       return make_error<GenericBinaryError>("Invalid table element type",
1051                                             object_error::parse_failed);
1052     }
1053   }
1054   if (Ctx.Ptr != Ctx.End)
1055     return make_error<GenericBinaryError>("Table section ended prematurely",
1056                                           object_error::parse_failed);
1057   return Error::success();
1058 }
1059 
parseMemorySection(ReadContext & Ctx)1060 Error WasmObjectFile::parseMemorySection(ReadContext &Ctx) {
1061   uint32_t Count = readVaruint32(Ctx);
1062   Memories.reserve(Count);
1063   while (Count--) {
1064     auto Limits = readLimits(Ctx);
1065     if (Limits.Flags & wasm::WASM_LIMITS_FLAG_IS_64)
1066       HasMemory64 = true;
1067     Memories.push_back(Limits);
1068   }
1069   if (Ctx.Ptr != Ctx.End)
1070     return make_error<GenericBinaryError>("Memory section ended prematurely",
1071                                           object_error::parse_failed);
1072   return Error::success();
1073 }
1074 
parseEventSection(ReadContext & Ctx)1075 Error WasmObjectFile::parseEventSection(ReadContext &Ctx) {
1076   EventSection = Sections.size();
1077   uint32_t Count = readVarint32(Ctx);
1078   Events.reserve(Count);
1079   while (Count--) {
1080     wasm::WasmEvent Event;
1081     Event.Index = NumImportedEvents + Events.size();
1082     Event.Type.Attribute = readVaruint32(Ctx);
1083     Event.Type.SigIndex = readVarint32(Ctx);
1084     Events.push_back(Event);
1085   }
1086 
1087   if (Ctx.Ptr != Ctx.End)
1088     return make_error<GenericBinaryError>("Event section ended prematurely",
1089                                           object_error::parse_failed);
1090   return Error::success();
1091 }
1092 
parseGlobalSection(ReadContext & Ctx)1093 Error WasmObjectFile::parseGlobalSection(ReadContext &Ctx) {
1094   GlobalSection = Sections.size();
1095   uint32_t Count = readVaruint32(Ctx);
1096   Globals.reserve(Count);
1097   while (Count--) {
1098     wasm::WasmGlobal Global;
1099     Global.Index = NumImportedGlobals + Globals.size();
1100     Global.Type.Type = readUint8(Ctx);
1101     Global.Type.Mutable = readVaruint1(Ctx);
1102     if (Error Err = readInitExpr(Global.InitExpr, Ctx))
1103       return Err;
1104     Globals.push_back(Global);
1105   }
1106   if (Ctx.Ptr != Ctx.End)
1107     return make_error<GenericBinaryError>("Global section ended prematurely",
1108                                           object_error::parse_failed);
1109   return Error::success();
1110 }
1111 
parseExportSection(ReadContext & Ctx)1112 Error WasmObjectFile::parseExportSection(ReadContext &Ctx) {
1113   uint32_t Count = readVaruint32(Ctx);
1114   Exports.reserve(Count);
1115   for (uint32_t I = 0; I < Count; I++) {
1116     wasm::WasmExport Ex;
1117     Ex.Name = readString(Ctx);
1118     Ex.Kind = readUint8(Ctx);
1119     Ex.Index = readVaruint32(Ctx);
1120     switch (Ex.Kind) {
1121     case wasm::WASM_EXTERNAL_FUNCTION:
1122 
1123       if (!isDefinedFunctionIndex(Ex.Index))
1124         return make_error<GenericBinaryError>("Invalid function export",
1125                                               object_error::parse_failed);
1126       getDefinedFunction(Ex.Index).ExportName = Ex.Name;
1127       break;
1128     case wasm::WASM_EXTERNAL_GLOBAL:
1129       if (!isValidGlobalIndex(Ex.Index))
1130         return make_error<GenericBinaryError>("Invalid global export",
1131                                               object_error::parse_failed);
1132       break;
1133     case wasm::WASM_EXTERNAL_EVENT:
1134       if (!isValidEventIndex(Ex.Index))
1135         return make_error<GenericBinaryError>("Invalid event export",
1136                                               object_error::parse_failed);
1137       break;
1138     case wasm::WASM_EXTERNAL_MEMORY:
1139     case wasm::WASM_EXTERNAL_TABLE:
1140       break;
1141     default:
1142       return make_error<GenericBinaryError>("Unexpected export kind",
1143                                             object_error::parse_failed);
1144     }
1145     Exports.push_back(Ex);
1146   }
1147   if (Ctx.Ptr != Ctx.End)
1148     return make_error<GenericBinaryError>("Export section ended prematurely",
1149                                           object_error::parse_failed);
1150   return Error::success();
1151 }
1152 
isValidFunctionIndex(uint32_t Index) const1153 bool WasmObjectFile::isValidFunctionIndex(uint32_t Index) const {
1154   return Index < NumImportedFunctions + FunctionTypes.size();
1155 }
1156 
isDefinedFunctionIndex(uint32_t Index) const1157 bool WasmObjectFile::isDefinedFunctionIndex(uint32_t Index) const {
1158   return Index >= NumImportedFunctions && isValidFunctionIndex(Index);
1159 }
1160 
isValidGlobalIndex(uint32_t Index) const1161 bool WasmObjectFile::isValidGlobalIndex(uint32_t Index) const {
1162   return Index < NumImportedGlobals + Globals.size();
1163 }
1164 
isValidTableIndex(uint32_t Index) const1165 bool WasmObjectFile::isValidTableIndex(uint32_t Index) const {
1166   return Index < NumImportedTables + Tables.size();
1167 }
1168 
isDefinedGlobalIndex(uint32_t Index) const1169 bool WasmObjectFile::isDefinedGlobalIndex(uint32_t Index) const {
1170   return Index >= NumImportedGlobals && isValidGlobalIndex(Index);
1171 }
1172 
isDefinedTableIndex(uint32_t Index) const1173 bool WasmObjectFile::isDefinedTableIndex(uint32_t Index) const {
1174   return Index >= NumImportedTables && isValidTableIndex(Index);
1175 }
1176 
isValidEventIndex(uint32_t Index) const1177 bool WasmObjectFile::isValidEventIndex(uint32_t Index) const {
1178   return Index < NumImportedEvents + Events.size();
1179 }
1180 
isDefinedEventIndex(uint32_t Index) const1181 bool WasmObjectFile::isDefinedEventIndex(uint32_t Index) const {
1182   return Index >= NumImportedEvents && isValidEventIndex(Index);
1183 }
1184 
isValidFunctionSymbol(uint32_t Index) const1185 bool WasmObjectFile::isValidFunctionSymbol(uint32_t Index) const {
1186   return Index < Symbols.size() && Symbols[Index].isTypeFunction();
1187 }
1188 
isValidTableSymbol(uint32_t Index) const1189 bool WasmObjectFile::isValidTableSymbol(uint32_t Index) const {
1190   return Index < Symbols.size() && Symbols[Index].isTypeTable();
1191 }
1192 
isValidGlobalSymbol(uint32_t Index) const1193 bool WasmObjectFile::isValidGlobalSymbol(uint32_t Index) const {
1194   return Index < Symbols.size() && Symbols[Index].isTypeGlobal();
1195 }
1196 
isValidEventSymbol(uint32_t Index) const1197 bool WasmObjectFile::isValidEventSymbol(uint32_t Index) const {
1198   return Index < Symbols.size() && Symbols[Index].isTypeEvent();
1199 }
1200 
isValidDataSymbol(uint32_t Index) const1201 bool WasmObjectFile::isValidDataSymbol(uint32_t Index) const {
1202   return Index < Symbols.size() && Symbols[Index].isTypeData();
1203 }
1204 
isValidSectionSymbol(uint32_t Index) const1205 bool WasmObjectFile::isValidSectionSymbol(uint32_t Index) const {
1206   return Index < Symbols.size() && Symbols[Index].isTypeSection();
1207 }
1208 
getDefinedFunction(uint32_t Index)1209 wasm::WasmFunction &WasmObjectFile::getDefinedFunction(uint32_t Index) {
1210   assert(isDefinedFunctionIndex(Index));
1211   return Functions[Index - NumImportedFunctions];
1212 }
1213 
1214 const wasm::WasmFunction &
getDefinedFunction(uint32_t Index) const1215 WasmObjectFile::getDefinedFunction(uint32_t Index) const {
1216   assert(isDefinedFunctionIndex(Index));
1217   return Functions[Index - NumImportedFunctions];
1218 }
1219 
getDefinedGlobal(uint32_t Index)1220 wasm::WasmGlobal &WasmObjectFile::getDefinedGlobal(uint32_t Index) {
1221   assert(isDefinedGlobalIndex(Index));
1222   return Globals[Index - NumImportedGlobals];
1223 }
1224 
getDefinedEvent(uint32_t Index)1225 wasm::WasmEvent &WasmObjectFile::getDefinedEvent(uint32_t Index) {
1226   assert(isDefinedEventIndex(Index));
1227   return Events[Index - NumImportedEvents];
1228 }
1229 
parseStartSection(ReadContext & Ctx)1230 Error WasmObjectFile::parseStartSection(ReadContext &Ctx) {
1231   StartFunction = readVaruint32(Ctx);
1232   if (!isValidFunctionIndex(StartFunction))
1233     return make_error<GenericBinaryError>("Invalid start function",
1234                                           object_error::parse_failed);
1235   return Error::success();
1236 }
1237 
parseCodeSection(ReadContext & Ctx)1238 Error WasmObjectFile::parseCodeSection(ReadContext &Ctx) {
1239   SeenCodeSection = true;
1240   CodeSection = Sections.size();
1241   uint32_t FunctionCount = readVaruint32(Ctx);
1242   if (FunctionCount != FunctionTypes.size()) {
1243     return make_error<GenericBinaryError>("Invalid function count",
1244                                           object_error::parse_failed);
1245   }
1246 
1247   for (uint32_t i = 0; i < FunctionCount; i++) {
1248     wasm::WasmFunction& Function = Functions[i];
1249     const uint8_t *FunctionStart = Ctx.Ptr;
1250     uint32_t Size = readVaruint32(Ctx);
1251     const uint8_t *FunctionEnd = Ctx.Ptr + Size;
1252 
1253     Function.CodeOffset = Ctx.Ptr - FunctionStart;
1254     Function.Index = NumImportedFunctions + i;
1255     Function.CodeSectionOffset = FunctionStart - Ctx.Start;
1256     Function.Size = FunctionEnd - FunctionStart;
1257 
1258     uint32_t NumLocalDecls = readVaruint32(Ctx);
1259     Function.Locals.reserve(NumLocalDecls);
1260     while (NumLocalDecls--) {
1261       wasm::WasmLocalDecl Decl;
1262       Decl.Count = readVaruint32(Ctx);
1263       Decl.Type = readUint8(Ctx);
1264       Function.Locals.push_back(Decl);
1265     }
1266 
1267     uint32_t BodySize = FunctionEnd - Ctx.Ptr;
1268     Function.Body = ArrayRef<uint8_t>(Ctx.Ptr, BodySize);
1269     // This will be set later when reading in the linking metadata section.
1270     Function.Comdat = UINT32_MAX;
1271     Ctx.Ptr += BodySize;
1272     assert(Ctx.Ptr == FunctionEnd);
1273   }
1274   if (Ctx.Ptr != Ctx.End)
1275     return make_error<GenericBinaryError>("Code section ended prematurely",
1276                                           object_error::parse_failed);
1277   return Error::success();
1278 }
1279 
parseElemSection(ReadContext & Ctx)1280 Error WasmObjectFile::parseElemSection(ReadContext &Ctx) {
1281   uint32_t Count = readVaruint32(Ctx);
1282   ElemSegments.reserve(Count);
1283   while (Count--) {
1284     wasm::WasmElemSegment Segment;
1285     Segment.TableIndex = readVaruint32(Ctx);
1286     if (Segment.TableIndex != 0) {
1287       return make_error<GenericBinaryError>("Invalid TableIndex",
1288                                             object_error::parse_failed);
1289     }
1290     if (Error Err = readInitExpr(Segment.Offset, Ctx))
1291       return Err;
1292     uint32_t NumElems = readVaruint32(Ctx);
1293     while (NumElems--) {
1294       Segment.Functions.push_back(readVaruint32(Ctx));
1295     }
1296     ElemSegments.push_back(Segment);
1297   }
1298   if (Ctx.Ptr != Ctx.End)
1299     return make_error<GenericBinaryError>("Elem section ended prematurely",
1300                                           object_error::parse_failed);
1301   return Error::success();
1302 }
1303 
parseDataSection(ReadContext & Ctx)1304 Error WasmObjectFile::parseDataSection(ReadContext &Ctx) {
1305   DataSection = Sections.size();
1306   uint32_t Count = readVaruint32(Ctx);
1307   if (DataCount && Count != DataCount.getValue())
1308     return make_error<GenericBinaryError>(
1309         "Number of data segments does not match DataCount section");
1310   DataSegments.reserve(Count);
1311   while (Count--) {
1312     WasmSegment Segment;
1313     Segment.Data.InitFlags = readVaruint32(Ctx);
1314     Segment.Data.MemoryIndex = (Segment.Data.InitFlags & wasm::WASM_SEGMENT_HAS_MEMINDEX)
1315                                ? readVaruint32(Ctx) : 0;
1316     if ((Segment.Data.InitFlags & wasm::WASM_SEGMENT_IS_PASSIVE) == 0) {
1317       if (Error Err = readInitExpr(Segment.Data.Offset, Ctx))
1318         return Err;
1319     } else {
1320       Segment.Data.Offset.Opcode = wasm::WASM_OPCODE_I32_CONST;
1321       Segment.Data.Offset.Value.Int32 = 0;
1322     }
1323     uint32_t Size = readVaruint32(Ctx);
1324     if (Size > (size_t)(Ctx.End - Ctx.Ptr))
1325       return make_error<GenericBinaryError>("Invalid segment size",
1326                                             object_error::parse_failed);
1327     Segment.Data.Content = ArrayRef<uint8_t>(Ctx.Ptr, Size);
1328     // The rest of these Data fields are set later, when reading in the linking
1329     // metadata section.
1330     Segment.Data.Alignment = 0;
1331     Segment.Data.LinkerFlags = 0;
1332     Segment.Data.Comdat = UINT32_MAX;
1333     Segment.SectionOffset = Ctx.Ptr - Ctx.Start;
1334     Ctx.Ptr += Size;
1335     DataSegments.push_back(Segment);
1336   }
1337   if (Ctx.Ptr != Ctx.End)
1338     return make_error<GenericBinaryError>("Data section ended prematurely",
1339                                           object_error::parse_failed);
1340   return Error::success();
1341 }
1342 
parseDataCountSection(ReadContext & Ctx)1343 Error WasmObjectFile::parseDataCountSection(ReadContext &Ctx) {
1344   DataCount = readVaruint32(Ctx);
1345   return Error::success();
1346 }
1347 
getHeader() const1348 const wasm::WasmObjectHeader &WasmObjectFile::getHeader() const {
1349   return Header;
1350 }
1351 
moveSymbolNext(DataRefImpl & Symb) const1352 void WasmObjectFile::moveSymbolNext(DataRefImpl &Symb) const { Symb.d.b++; }
1353 
getSymbolFlags(DataRefImpl Symb) const1354 Expected<uint32_t> WasmObjectFile::getSymbolFlags(DataRefImpl Symb) const {
1355   uint32_t Result = SymbolRef::SF_None;
1356   const WasmSymbol &Sym = getWasmSymbol(Symb);
1357 
1358   LLVM_DEBUG(dbgs() << "getSymbolFlags: ptr=" << &Sym << " " << Sym << "\n");
1359   if (Sym.isBindingWeak())
1360     Result |= SymbolRef::SF_Weak;
1361   if (!Sym.isBindingLocal())
1362     Result |= SymbolRef::SF_Global;
1363   if (Sym.isHidden())
1364     Result |= SymbolRef::SF_Hidden;
1365   if (!Sym.isDefined())
1366     Result |= SymbolRef::SF_Undefined;
1367   if (Sym.isTypeFunction())
1368     Result |= SymbolRef::SF_Executable;
1369   return Result;
1370 }
1371 
symbol_begin() const1372 basic_symbol_iterator WasmObjectFile::symbol_begin() const {
1373   DataRefImpl Ref;
1374   Ref.d.a = 1; // Arbitrary non-zero value so that Ref.p is non-null
1375   Ref.d.b = 0; // Symbol index
1376   return BasicSymbolRef(Ref, this);
1377 }
1378 
symbol_end() const1379 basic_symbol_iterator WasmObjectFile::symbol_end() const {
1380   DataRefImpl Ref;
1381   Ref.d.a = 1; // Arbitrary non-zero value so that Ref.p is non-null
1382   Ref.d.b = Symbols.size(); // Symbol index
1383   return BasicSymbolRef(Ref, this);
1384 }
1385 
getWasmSymbol(const DataRefImpl & Symb) const1386 const WasmSymbol &WasmObjectFile::getWasmSymbol(const DataRefImpl &Symb) const {
1387   return Symbols[Symb.d.b];
1388 }
1389 
getWasmSymbol(const SymbolRef & Symb) const1390 const WasmSymbol &WasmObjectFile::getWasmSymbol(const SymbolRef &Symb) const {
1391   return getWasmSymbol(Symb.getRawDataRefImpl());
1392 }
1393 
getSymbolName(DataRefImpl Symb) const1394 Expected<StringRef> WasmObjectFile::getSymbolName(DataRefImpl Symb) const {
1395   return getWasmSymbol(Symb).Info.Name;
1396 }
1397 
getSymbolAddress(DataRefImpl Symb) const1398 Expected<uint64_t> WasmObjectFile::getSymbolAddress(DataRefImpl Symb) const {
1399   auto &Sym = getWasmSymbol(Symb);
1400   if (Sym.Info.Kind == wasm::WASM_SYMBOL_TYPE_FUNCTION &&
1401       isDefinedFunctionIndex(Sym.Info.ElementIndex))
1402     return getDefinedFunction(Sym.Info.ElementIndex).CodeSectionOffset;
1403   else
1404     return getSymbolValue(Symb);
1405 }
1406 
getWasmSymbolValue(const WasmSymbol & Sym) const1407 uint64_t WasmObjectFile::getWasmSymbolValue(const WasmSymbol &Sym) const {
1408   switch (Sym.Info.Kind) {
1409   case wasm::WASM_SYMBOL_TYPE_FUNCTION:
1410   case wasm::WASM_SYMBOL_TYPE_GLOBAL:
1411   case wasm::WASM_SYMBOL_TYPE_EVENT:
1412     return Sym.Info.ElementIndex;
1413   case wasm::WASM_SYMBOL_TYPE_DATA: {
1414     // The value of a data symbol is the segment offset, plus the symbol
1415     // offset within the segment.
1416     uint32_t SegmentIndex = Sym.Info.DataRef.Segment;
1417     const wasm::WasmDataSegment &Segment = DataSegments[SegmentIndex].Data;
1418     if (Segment.Offset.Opcode == wasm::WASM_OPCODE_I32_CONST) {
1419       return Segment.Offset.Value.Int32 + Sym.Info.DataRef.Offset;
1420     } else if (Segment.Offset.Opcode == wasm::WASM_OPCODE_I64_CONST) {
1421       return Segment.Offset.Value.Int64 + Sym.Info.DataRef.Offset;
1422     } else {
1423       llvm_unreachable("unknown init expr opcode");
1424     }
1425   }
1426   case wasm::WASM_SYMBOL_TYPE_SECTION:
1427     return 0;
1428   }
1429   llvm_unreachable("invalid symbol type");
1430 }
1431 
getSymbolValueImpl(DataRefImpl Symb) const1432 uint64_t WasmObjectFile::getSymbolValueImpl(DataRefImpl Symb) const {
1433   return getWasmSymbolValue(getWasmSymbol(Symb));
1434 }
1435 
getSymbolAlignment(DataRefImpl Symb) const1436 uint32_t WasmObjectFile::getSymbolAlignment(DataRefImpl Symb) const {
1437   llvm_unreachable("not yet implemented");
1438   return 0;
1439 }
1440 
getCommonSymbolSizeImpl(DataRefImpl Symb) const1441 uint64_t WasmObjectFile::getCommonSymbolSizeImpl(DataRefImpl Symb) const {
1442   llvm_unreachable("not yet implemented");
1443   return 0;
1444 }
1445 
1446 Expected<SymbolRef::Type>
getSymbolType(DataRefImpl Symb) const1447 WasmObjectFile::getSymbolType(DataRefImpl Symb) const {
1448   const WasmSymbol &Sym = getWasmSymbol(Symb);
1449 
1450   switch (Sym.Info.Kind) {
1451   case wasm::WASM_SYMBOL_TYPE_FUNCTION:
1452     return SymbolRef::ST_Function;
1453   case wasm::WASM_SYMBOL_TYPE_GLOBAL:
1454     return SymbolRef::ST_Other;
1455   case wasm::WASM_SYMBOL_TYPE_DATA:
1456     return SymbolRef::ST_Data;
1457   case wasm::WASM_SYMBOL_TYPE_SECTION:
1458     return SymbolRef::ST_Debug;
1459   case wasm::WASM_SYMBOL_TYPE_EVENT:
1460     return SymbolRef::ST_Other;
1461   }
1462 
1463   llvm_unreachable("Unknown WasmSymbol::SymbolType");
1464   return SymbolRef::ST_Other;
1465 }
1466 
1467 Expected<section_iterator>
getSymbolSection(DataRefImpl Symb) const1468 WasmObjectFile::getSymbolSection(DataRefImpl Symb) const {
1469   const WasmSymbol &Sym = getWasmSymbol(Symb);
1470   if (Sym.isUndefined())
1471     return section_end();
1472 
1473   DataRefImpl Ref;
1474   Ref.d.a = getSymbolSectionIdImpl(Sym);
1475   return section_iterator(SectionRef(Ref, this));
1476 }
1477 
getSymbolSectionId(SymbolRef Symb) const1478 uint32_t WasmObjectFile::getSymbolSectionId(SymbolRef Symb) const {
1479   const WasmSymbol &Sym = getWasmSymbol(Symb);
1480   return getSymbolSectionIdImpl(Sym);
1481 }
1482 
getSymbolSectionIdImpl(const WasmSymbol & Sym) const1483 uint32_t WasmObjectFile::getSymbolSectionIdImpl(const WasmSymbol &Sym) const {
1484   switch (Sym.Info.Kind) {
1485   case wasm::WASM_SYMBOL_TYPE_FUNCTION:
1486     return CodeSection;
1487   case wasm::WASM_SYMBOL_TYPE_GLOBAL:
1488     return GlobalSection;
1489   case wasm::WASM_SYMBOL_TYPE_DATA:
1490     return DataSection;
1491   case wasm::WASM_SYMBOL_TYPE_SECTION:
1492     return Sym.Info.ElementIndex;
1493   case wasm::WASM_SYMBOL_TYPE_EVENT:
1494     return EventSection;
1495   default:
1496     llvm_unreachable("Unknown WasmSymbol::SymbolType");
1497   }
1498 }
1499 
moveSectionNext(DataRefImpl & Sec) const1500 void WasmObjectFile::moveSectionNext(DataRefImpl &Sec) const { Sec.d.a++; }
1501 
getSectionName(DataRefImpl Sec) const1502 Expected<StringRef> WasmObjectFile::getSectionName(DataRefImpl Sec) const {
1503   const WasmSection &S = Sections[Sec.d.a];
1504 #define ECase(X)                                                               \
1505   case wasm::WASM_SEC_##X:                                                     \
1506     return #X;
1507   switch (S.Type) {
1508     ECase(TYPE);
1509     ECase(IMPORT);
1510     ECase(FUNCTION);
1511     ECase(TABLE);
1512     ECase(MEMORY);
1513     ECase(GLOBAL);
1514     ECase(EVENT);
1515     ECase(EXPORT);
1516     ECase(START);
1517     ECase(ELEM);
1518     ECase(CODE);
1519     ECase(DATA);
1520     ECase(DATACOUNT);
1521   case wasm::WASM_SEC_CUSTOM:
1522     return S.Name;
1523   default:
1524     return createStringError(object_error::invalid_section_index, "");
1525   }
1526 #undef ECase
1527 }
1528 
getSectionAddress(DataRefImpl Sec) const1529 uint64_t WasmObjectFile::getSectionAddress(DataRefImpl Sec) const { return 0; }
1530 
getSectionIndex(DataRefImpl Sec) const1531 uint64_t WasmObjectFile::getSectionIndex(DataRefImpl Sec) const {
1532   return Sec.d.a;
1533 }
1534 
getSectionSize(DataRefImpl Sec) const1535 uint64_t WasmObjectFile::getSectionSize(DataRefImpl Sec) const {
1536   const WasmSection &S = Sections[Sec.d.a];
1537   return S.Content.size();
1538 }
1539 
1540 Expected<ArrayRef<uint8_t>>
getSectionContents(DataRefImpl Sec) const1541 WasmObjectFile::getSectionContents(DataRefImpl Sec) const {
1542   const WasmSection &S = Sections[Sec.d.a];
1543   // This will never fail since wasm sections can never be empty (user-sections
1544   // must have a name and non-user sections each have a defined structure).
1545   return S.Content;
1546 }
1547 
getSectionAlignment(DataRefImpl Sec) const1548 uint64_t WasmObjectFile::getSectionAlignment(DataRefImpl Sec) const {
1549   return 1;
1550 }
1551 
isSectionCompressed(DataRefImpl Sec) const1552 bool WasmObjectFile::isSectionCompressed(DataRefImpl Sec) const {
1553   return false;
1554 }
1555 
isSectionText(DataRefImpl Sec) const1556 bool WasmObjectFile::isSectionText(DataRefImpl Sec) const {
1557   return getWasmSection(Sec).Type == wasm::WASM_SEC_CODE;
1558 }
1559 
isSectionData(DataRefImpl Sec) const1560 bool WasmObjectFile::isSectionData(DataRefImpl Sec) const {
1561   return getWasmSection(Sec).Type == wasm::WASM_SEC_DATA;
1562 }
1563 
isSectionBSS(DataRefImpl Sec) const1564 bool WasmObjectFile::isSectionBSS(DataRefImpl Sec) const { return false; }
1565 
isSectionVirtual(DataRefImpl Sec) const1566 bool WasmObjectFile::isSectionVirtual(DataRefImpl Sec) const { return false; }
1567 
section_rel_begin(DataRefImpl Ref) const1568 relocation_iterator WasmObjectFile::section_rel_begin(DataRefImpl Ref) const {
1569   DataRefImpl RelocRef;
1570   RelocRef.d.a = Ref.d.a;
1571   RelocRef.d.b = 0;
1572   return relocation_iterator(RelocationRef(RelocRef, this));
1573 }
1574 
section_rel_end(DataRefImpl Ref) const1575 relocation_iterator WasmObjectFile::section_rel_end(DataRefImpl Ref) const {
1576   const WasmSection &Sec = getWasmSection(Ref);
1577   DataRefImpl RelocRef;
1578   RelocRef.d.a = Ref.d.a;
1579   RelocRef.d.b = Sec.Relocations.size();
1580   return relocation_iterator(RelocationRef(RelocRef, this));
1581 }
1582 
moveRelocationNext(DataRefImpl & Rel) const1583 void WasmObjectFile::moveRelocationNext(DataRefImpl &Rel) const { Rel.d.b++; }
1584 
getRelocationOffset(DataRefImpl Ref) const1585 uint64_t WasmObjectFile::getRelocationOffset(DataRefImpl Ref) const {
1586   const wasm::WasmRelocation &Rel = getWasmRelocation(Ref);
1587   return Rel.Offset;
1588 }
1589 
getRelocationSymbol(DataRefImpl Ref) const1590 symbol_iterator WasmObjectFile::getRelocationSymbol(DataRefImpl Ref) const {
1591   const wasm::WasmRelocation &Rel = getWasmRelocation(Ref);
1592   if (Rel.Type == wasm::R_WASM_TYPE_INDEX_LEB)
1593     return symbol_end();
1594   DataRefImpl Sym;
1595   Sym.d.a = 1;
1596   Sym.d.b = Rel.Index;
1597   return symbol_iterator(SymbolRef(Sym, this));
1598 }
1599 
getRelocationType(DataRefImpl Ref) const1600 uint64_t WasmObjectFile::getRelocationType(DataRefImpl Ref) const {
1601   const wasm::WasmRelocation &Rel = getWasmRelocation(Ref);
1602   return Rel.Type;
1603 }
1604 
getRelocationTypeName(DataRefImpl Ref,SmallVectorImpl<char> & Result) const1605 void WasmObjectFile::getRelocationTypeName(
1606     DataRefImpl Ref, SmallVectorImpl<char> &Result) const {
1607   const wasm::WasmRelocation &Rel = getWasmRelocation(Ref);
1608   StringRef Res = "Unknown";
1609 
1610 #define WASM_RELOC(name, value)                                                \
1611   case wasm::name:                                                             \
1612     Res = #name;                                                               \
1613     break;
1614 
1615   switch (Rel.Type) {
1616 #include "llvm/BinaryFormat/WasmRelocs.def"
1617   }
1618 
1619 #undef WASM_RELOC
1620 
1621   Result.append(Res.begin(), Res.end());
1622 }
1623 
section_begin() const1624 section_iterator WasmObjectFile::section_begin() const {
1625   DataRefImpl Ref;
1626   Ref.d.a = 0;
1627   return section_iterator(SectionRef(Ref, this));
1628 }
1629 
section_end() const1630 section_iterator WasmObjectFile::section_end() const {
1631   DataRefImpl Ref;
1632   Ref.d.a = Sections.size();
1633   return section_iterator(SectionRef(Ref, this));
1634 }
1635 
getBytesInAddress() const1636 uint8_t WasmObjectFile::getBytesInAddress() const {
1637   return HasMemory64 ? 8 : 4;
1638 }
1639 
getFileFormatName() const1640 StringRef WasmObjectFile::getFileFormatName() const { return "WASM"; }
1641 
getArch() const1642 Triple::ArchType WasmObjectFile::getArch() const {
1643   return HasMemory64 ? Triple::wasm64 : Triple::wasm32;
1644 }
1645 
getFeatures() const1646 SubtargetFeatures WasmObjectFile::getFeatures() const {
1647   return SubtargetFeatures();
1648 }
1649 
isRelocatableObject() const1650 bool WasmObjectFile::isRelocatableObject() const { return HasLinkingSection; }
1651 
isSharedObject() const1652 bool WasmObjectFile::isSharedObject() const { return HasDylinkSection; }
1653 
getWasmSection(DataRefImpl Ref) const1654 const WasmSection &WasmObjectFile::getWasmSection(DataRefImpl Ref) const {
1655   assert(Ref.d.a < Sections.size());
1656   return Sections[Ref.d.a];
1657 }
1658 
1659 const WasmSection &
getWasmSection(const SectionRef & Section) const1660 WasmObjectFile::getWasmSection(const SectionRef &Section) const {
1661   return getWasmSection(Section.getRawDataRefImpl());
1662 }
1663 
1664 const wasm::WasmRelocation &
getWasmRelocation(const RelocationRef & Ref) const1665 WasmObjectFile::getWasmRelocation(const RelocationRef &Ref) const {
1666   return getWasmRelocation(Ref.getRawDataRefImpl());
1667 }
1668 
1669 const wasm::WasmRelocation &
getWasmRelocation(DataRefImpl Ref) const1670 WasmObjectFile::getWasmRelocation(DataRefImpl Ref) const {
1671   assert(Ref.d.a < Sections.size());
1672   const WasmSection &Sec = Sections[Ref.d.a];
1673   assert(Ref.d.b < Sec.Relocations.size());
1674   return Sec.Relocations[Ref.d.b];
1675 }
1676 
getSectionOrder(unsigned ID,StringRef CustomSectionName)1677 int WasmSectionOrderChecker::getSectionOrder(unsigned ID,
1678                                              StringRef CustomSectionName) {
1679   switch (ID) {
1680   case wasm::WASM_SEC_CUSTOM:
1681     return StringSwitch<unsigned>(CustomSectionName)
1682         .Case("dylink", WASM_SEC_ORDER_DYLINK)
1683         .Case("linking", WASM_SEC_ORDER_LINKING)
1684         .StartsWith("reloc.", WASM_SEC_ORDER_RELOC)
1685         .Case("name", WASM_SEC_ORDER_NAME)
1686         .Case("producers", WASM_SEC_ORDER_PRODUCERS)
1687         .Case("target_features", WASM_SEC_ORDER_TARGET_FEATURES)
1688         .Default(WASM_SEC_ORDER_NONE);
1689   case wasm::WASM_SEC_TYPE:
1690     return WASM_SEC_ORDER_TYPE;
1691   case wasm::WASM_SEC_IMPORT:
1692     return WASM_SEC_ORDER_IMPORT;
1693   case wasm::WASM_SEC_FUNCTION:
1694     return WASM_SEC_ORDER_FUNCTION;
1695   case wasm::WASM_SEC_TABLE:
1696     return WASM_SEC_ORDER_TABLE;
1697   case wasm::WASM_SEC_MEMORY:
1698     return WASM_SEC_ORDER_MEMORY;
1699   case wasm::WASM_SEC_GLOBAL:
1700     return WASM_SEC_ORDER_GLOBAL;
1701   case wasm::WASM_SEC_EXPORT:
1702     return WASM_SEC_ORDER_EXPORT;
1703   case wasm::WASM_SEC_START:
1704     return WASM_SEC_ORDER_START;
1705   case wasm::WASM_SEC_ELEM:
1706     return WASM_SEC_ORDER_ELEM;
1707   case wasm::WASM_SEC_CODE:
1708     return WASM_SEC_ORDER_CODE;
1709   case wasm::WASM_SEC_DATA:
1710     return WASM_SEC_ORDER_DATA;
1711   case wasm::WASM_SEC_DATACOUNT:
1712     return WASM_SEC_ORDER_DATACOUNT;
1713   case wasm::WASM_SEC_EVENT:
1714     return WASM_SEC_ORDER_EVENT;
1715   default:
1716     return WASM_SEC_ORDER_NONE;
1717   }
1718 }
1719 
1720 // Represents the edges in a directed graph where any node B reachable from node
1721 // A is not allowed to appear before A in the section ordering, but may appear
1722 // afterward.
1723 int WasmSectionOrderChecker::DisallowedPredecessors
1724     [WASM_NUM_SEC_ORDERS][WASM_NUM_SEC_ORDERS] = {
1725         // WASM_SEC_ORDER_NONE
1726         {},
1727         // WASM_SEC_ORDER_TYPE
1728         {WASM_SEC_ORDER_TYPE, WASM_SEC_ORDER_IMPORT},
1729         // WASM_SEC_ORDER_IMPORT
1730         {WASM_SEC_ORDER_IMPORT, WASM_SEC_ORDER_FUNCTION},
1731         // WASM_SEC_ORDER_FUNCTION
1732         {WASM_SEC_ORDER_FUNCTION, WASM_SEC_ORDER_TABLE},
1733         // WASM_SEC_ORDER_TABLE
1734         {WASM_SEC_ORDER_TABLE, WASM_SEC_ORDER_MEMORY},
1735         // WASM_SEC_ORDER_MEMORY
1736         {WASM_SEC_ORDER_MEMORY, WASM_SEC_ORDER_EVENT},
1737         // WASM_SEC_ORDER_EVENT
1738         {WASM_SEC_ORDER_EVENT, WASM_SEC_ORDER_GLOBAL},
1739         // WASM_SEC_ORDER_GLOBAL
1740         {WASM_SEC_ORDER_GLOBAL, WASM_SEC_ORDER_EXPORT},
1741         // WASM_SEC_ORDER_EXPORT
1742         {WASM_SEC_ORDER_EXPORT, WASM_SEC_ORDER_START},
1743         // WASM_SEC_ORDER_START
1744         {WASM_SEC_ORDER_START, WASM_SEC_ORDER_ELEM},
1745         // WASM_SEC_ORDER_ELEM
1746         {WASM_SEC_ORDER_ELEM, WASM_SEC_ORDER_DATACOUNT},
1747         // WASM_SEC_ORDER_DATACOUNT
1748         {WASM_SEC_ORDER_DATACOUNT, WASM_SEC_ORDER_CODE},
1749         // WASM_SEC_ORDER_CODE
1750         {WASM_SEC_ORDER_CODE, WASM_SEC_ORDER_DATA},
1751         // WASM_SEC_ORDER_DATA
1752         {WASM_SEC_ORDER_DATA, WASM_SEC_ORDER_LINKING},
1753 
1754         // Custom Sections
1755         // WASM_SEC_ORDER_DYLINK
1756         {WASM_SEC_ORDER_DYLINK, WASM_SEC_ORDER_TYPE},
1757         // WASM_SEC_ORDER_LINKING
1758         {WASM_SEC_ORDER_LINKING, WASM_SEC_ORDER_RELOC, WASM_SEC_ORDER_NAME},
1759         // WASM_SEC_ORDER_RELOC (can be repeated)
1760         {},
1761         // WASM_SEC_ORDER_NAME
1762         {WASM_SEC_ORDER_NAME, WASM_SEC_ORDER_PRODUCERS},
1763         // WASM_SEC_ORDER_PRODUCERS
1764         {WASM_SEC_ORDER_PRODUCERS, WASM_SEC_ORDER_TARGET_FEATURES},
1765         // WASM_SEC_ORDER_TARGET_FEATURES
1766         {WASM_SEC_ORDER_TARGET_FEATURES}};
1767 
isValidSectionOrder(unsigned ID,StringRef CustomSectionName)1768 bool WasmSectionOrderChecker::isValidSectionOrder(unsigned ID,
1769                                                   StringRef CustomSectionName) {
1770   int Order = getSectionOrder(ID, CustomSectionName);
1771   if (Order == WASM_SEC_ORDER_NONE)
1772     return true;
1773 
1774   // Disallowed predecessors we need to check for
1775   SmallVector<int, WASM_NUM_SEC_ORDERS> WorkList;
1776 
1777   // Keep track of completed checks to avoid repeating work
1778   bool Checked[WASM_NUM_SEC_ORDERS] = {};
1779 
1780   int Curr = Order;
1781   while (true) {
1782     // Add new disallowed predecessors to work list
1783     for (size_t I = 0;; ++I) {
1784       int Next = DisallowedPredecessors[Curr][I];
1785       if (Next == WASM_SEC_ORDER_NONE)
1786         break;
1787       if (Checked[Next])
1788         continue;
1789       WorkList.push_back(Next);
1790       Checked[Next] = true;
1791     }
1792 
1793     if (WorkList.empty())
1794       break;
1795 
1796     // Consider next disallowed predecessor
1797     Curr = WorkList.pop_back_val();
1798     if (Seen[Curr])
1799       return false;
1800   }
1801 
1802   // Have not seen any disallowed predecessors
1803   Seen[Order] = true;
1804   return true;
1805 }
1806