1 //===- Wasm.h - Wasm object file implementation -----------------*- C++ -*-===// 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 // This file declares the WasmObjectFile class, which implements the ObjectFile 10 // interface for Wasm files. 11 // 12 // See: https://github.com/WebAssembly/design/blob/main/BinaryEncoding.md 13 // 14 //===----------------------------------------------------------------------===// 15 16 #ifndef LLVM_OBJECT_WASM_H 17 #define LLVM_OBJECT_WASM_H 18 19 #include "llvm/ADT/ArrayRef.h" 20 #include "llvm/ADT/StringRef.h" 21 #include "llvm/BinaryFormat/Wasm.h" 22 #include "llvm/Config/llvm-config.h" 23 #include "llvm/MC/MCSymbolWasm.h" 24 #include "llvm/Object/Binary.h" 25 #include "llvm/Object/ObjectFile.h" 26 #include "llvm/Support/Error.h" 27 #include "llvm/Support/MemoryBuffer.h" 28 #include <cstddef> 29 #include <cstdint> 30 #include <vector> 31 32 namespace llvm { 33 namespace object { 34 35 class WasmSymbol { 36 public: WasmSymbol(const wasm::WasmSymbolInfo & Info,const wasm::WasmGlobalType * GlobalType,const wasm::WasmTableType * TableType,const wasm::WasmSignature * Signature)37 WasmSymbol(const wasm::WasmSymbolInfo &Info, 38 const wasm::WasmGlobalType *GlobalType, 39 const wasm::WasmTableType *TableType, 40 const wasm::WasmSignature *Signature) 41 : Info(Info), GlobalType(GlobalType), TableType(TableType), 42 Signature(Signature) { 43 assert(!Signature || Signature->Kind != wasm::WasmSignature::Placeholder); 44 } 45 46 // Symbol info as represented in the symbol's 'syminfo' entry of an object 47 // file's symbol table. 48 wasm::WasmSymbolInfo Info; 49 const wasm::WasmGlobalType *GlobalType; 50 const wasm::WasmTableType *TableType; 51 const wasm::WasmSignature *Signature; 52 isTypeFunction()53 bool isTypeFunction() const { 54 return Info.Kind == wasm::WASM_SYMBOL_TYPE_FUNCTION; 55 } 56 isTypeTable()57 bool isTypeTable() const { return Info.Kind == wasm::WASM_SYMBOL_TYPE_TABLE; } 58 isTypeData()59 bool isTypeData() const { return Info.Kind == wasm::WASM_SYMBOL_TYPE_DATA; } 60 isTypeGlobal()61 bool isTypeGlobal() const { 62 return Info.Kind == wasm::WASM_SYMBOL_TYPE_GLOBAL; 63 } 64 isTypeSection()65 bool isTypeSection() const { 66 return Info.Kind == wasm::WASM_SYMBOL_TYPE_SECTION; 67 } 68 isTypeTag()69 bool isTypeTag() const { return Info.Kind == wasm::WASM_SYMBOL_TYPE_TAG; } 70 isDefined()71 bool isDefined() const { return !isUndefined(); } 72 isUndefined()73 bool isUndefined() const { 74 return (Info.Flags & wasm::WASM_SYMBOL_UNDEFINED) != 0; 75 } 76 isBindingWeak()77 bool isBindingWeak() const { 78 return getBinding() == wasm::WASM_SYMBOL_BINDING_WEAK; 79 } 80 isBindingGlobal()81 bool isBindingGlobal() const { 82 return getBinding() == wasm::WASM_SYMBOL_BINDING_GLOBAL; 83 } 84 isBindingLocal()85 bool isBindingLocal() const { 86 return getBinding() == wasm::WASM_SYMBOL_BINDING_LOCAL; 87 } 88 getBinding()89 unsigned getBinding() const { 90 return Info.Flags & wasm::WASM_SYMBOL_BINDING_MASK; 91 } 92 isHidden()93 bool isHidden() const { 94 return getVisibility() == wasm::WASM_SYMBOL_VISIBILITY_HIDDEN; 95 } 96 getVisibility()97 unsigned getVisibility() const { 98 return Info.Flags & wasm::WASM_SYMBOL_VISIBILITY_MASK; 99 } 100 101 void print(raw_ostream &Out) const; 102 103 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) 104 LLVM_DUMP_METHOD void dump() const; 105 #endif 106 }; 107 108 struct WasmSection { 109 WasmSection() = default; 110 111 uint32_t Type = 0; 112 uint32_t Offset = 0; // Offset within the file 113 StringRef Name; // Section name (User-defined sections only) 114 uint32_t Comdat = UINT32_MAX; // From the "comdat info" section 115 ArrayRef<uint8_t> Content; 116 std::vector<wasm::WasmRelocation> Relocations; 117 // Length of the LEB encoding of the section header's size field 118 std::optional<uint8_t> HeaderSecSizeEncodingLen; 119 }; 120 121 struct WasmSegment { 122 uint32_t SectionOffset; 123 wasm::WasmDataSegment Data; 124 }; 125 126 class WasmObjectFile : public ObjectFile { 127 128 public: 129 WasmObjectFile(MemoryBufferRef Object, Error &Err); 130 131 const wasm::WasmObjectHeader &getHeader() const; 132 const WasmSymbol &getWasmSymbol(const DataRefImpl &Symb) const; 133 const WasmSymbol &getWasmSymbol(const SymbolRef &Symbol) const; 134 const WasmSection &getWasmSection(const SectionRef &Section) const; 135 const wasm::WasmRelocation &getWasmRelocation(const RelocationRef &Ref) const; 136 classof(const Binary * v)137 static bool classof(const Binary *v) { return v->isWasm(); } 138 dylinkInfo()139 const wasm::WasmDylinkInfo &dylinkInfo() const { return DylinkInfo; } getProducerInfo()140 const wasm::WasmProducerInfo &getProducerInfo() const { return ProducerInfo; } getTargetFeatures()141 ArrayRef<wasm::WasmFeatureEntry> getTargetFeatures() const { 142 return TargetFeatures; 143 } types()144 ArrayRef<wasm::WasmSignature> types() const { return Signatures; } imports()145 ArrayRef<wasm::WasmImport> imports() const { return Imports; } tables()146 ArrayRef<wasm::WasmTable> tables() const { return Tables; } memories()147 ArrayRef<wasm::WasmLimits> memories() const { return Memories; } globals()148 ArrayRef<wasm::WasmGlobal> globals() const { return Globals; } tags()149 ArrayRef<wasm::WasmTag> tags() const { return Tags; } exports()150 ArrayRef<wasm::WasmExport> exports() const { return Exports; } linkingData()151 const wasm::WasmLinkingData &linkingData() const { return LinkingData; } getNumberOfSymbols()152 uint32_t getNumberOfSymbols() const { return Symbols.size(); } elements()153 ArrayRef<wasm::WasmElemSegment> elements() const { return ElemSegments; } dataSegments()154 ArrayRef<WasmSegment> dataSegments() const { return DataSegments; } functions()155 ArrayRef<wasm::WasmFunction> functions() const { return Functions; } debugNames()156 ArrayRef<wasm::WasmDebugName> debugNames() const { return DebugNames; } startFunction()157 uint32_t startFunction() const { return StartFunction; } getNumImportedGlobals()158 uint32_t getNumImportedGlobals() const { return NumImportedGlobals; } getNumImportedTables()159 uint32_t getNumImportedTables() const { return NumImportedTables; } getNumImportedFunctions()160 uint32_t getNumImportedFunctions() const { return NumImportedFunctions; } getNumImportedTags()161 uint32_t getNumImportedTags() const { return NumImportedTags; } getNumSections()162 uint32_t getNumSections() const { return Sections.size(); } 163 void moveSymbolNext(DataRefImpl &Symb) const override; 164 165 Expected<uint32_t> getSymbolFlags(DataRefImpl Symb) const override; 166 167 basic_symbol_iterator symbol_begin() const override; 168 169 basic_symbol_iterator symbol_end() const override; 170 Expected<StringRef> getSymbolName(DataRefImpl Symb) const override; 171 is64Bit()172 bool is64Bit() const override { return false; } 173 174 Expected<uint64_t> getSymbolAddress(DataRefImpl Symb) const override; 175 uint64_t getWasmSymbolValue(const WasmSymbol &Sym) const; 176 uint64_t getSymbolValueImpl(DataRefImpl Symb) const override; 177 uint32_t getSymbolAlignment(DataRefImpl Symb) const override; 178 uint64_t getCommonSymbolSizeImpl(DataRefImpl Symb) const override; 179 Expected<SymbolRef::Type> getSymbolType(DataRefImpl Symb) const override; 180 Expected<section_iterator> getSymbolSection(DataRefImpl Symb) const override; 181 uint32_t getSymbolSectionId(SymbolRef Sym) const; 182 uint32_t getSymbolSize(SymbolRef Sym) const; 183 184 // Overrides from SectionRef. 185 void moveSectionNext(DataRefImpl &Sec) const override; 186 Expected<StringRef> getSectionName(DataRefImpl Sec) const override; 187 uint64_t getSectionAddress(DataRefImpl Sec) const override; 188 uint64_t getSectionIndex(DataRefImpl Sec) const override; 189 uint64_t getSectionSize(DataRefImpl Sec) const override; 190 Expected<ArrayRef<uint8_t>> 191 getSectionContents(DataRefImpl Sec) const override; 192 uint64_t getSectionAlignment(DataRefImpl Sec) const override; 193 bool isSectionCompressed(DataRefImpl Sec) const override; 194 bool isSectionText(DataRefImpl Sec) const override; 195 bool isSectionData(DataRefImpl Sec) const override; 196 bool isSectionBSS(DataRefImpl Sec) const override; 197 bool isSectionVirtual(DataRefImpl Sec) const override; 198 relocation_iterator section_rel_begin(DataRefImpl Sec) const override; 199 relocation_iterator section_rel_end(DataRefImpl Sec) const override; 200 201 // Overrides from RelocationRef. 202 void moveRelocationNext(DataRefImpl &Rel) const override; 203 uint64_t getRelocationOffset(DataRefImpl Rel) const override; 204 symbol_iterator getRelocationSymbol(DataRefImpl Rel) const override; 205 uint64_t getRelocationType(DataRefImpl Rel) const override; 206 void getRelocationTypeName(DataRefImpl Rel, 207 SmallVectorImpl<char> &Result) const override; 208 209 section_iterator section_begin() const override; 210 section_iterator section_end() const override; 211 uint8_t getBytesInAddress() const override; 212 StringRef getFileFormatName() const override; 213 Triple::ArchType getArch() const override; 214 Expected<SubtargetFeatures> getFeatures() const override; 215 bool isRelocatableObject() const override; 216 bool isSharedObject() const; hasUnmodeledTypes()217 bool hasUnmodeledTypes() const { return HasUnmodeledTypes; } 218 219 struct ReadContext { 220 const uint8_t *Start; 221 const uint8_t *Ptr; 222 const uint8_t *End; 223 }; 224 225 private: 226 bool isValidFunctionIndex(uint32_t Index) const; 227 bool isDefinedFunctionIndex(uint32_t Index) const; 228 bool isValidGlobalIndex(uint32_t Index) const; 229 bool isValidTableNumber(uint32_t Index) const; 230 bool isDefinedGlobalIndex(uint32_t Index) const; 231 bool isDefinedTableNumber(uint32_t Index) const; 232 bool isValidTagIndex(uint32_t Index) const; 233 bool isDefinedTagIndex(uint32_t Index) const; 234 bool isValidFunctionSymbol(uint32_t Index) const; 235 bool isValidTableSymbol(uint32_t Index) const; 236 bool isValidGlobalSymbol(uint32_t Index) const; 237 bool isValidTagSymbol(uint32_t Index) const; 238 bool isValidDataSymbol(uint32_t Index) const; 239 bool isValidSectionSymbol(uint32_t Index) const; 240 wasm::WasmFunction &getDefinedFunction(uint32_t Index); 241 const wasm::WasmFunction &getDefinedFunction(uint32_t Index) const; 242 const wasm::WasmGlobal &getDefinedGlobal(uint32_t Index) const; 243 wasm::WasmTag &getDefinedTag(uint32_t Index); 244 245 const WasmSection &getWasmSection(DataRefImpl Ref) const; 246 const wasm::WasmRelocation &getWasmRelocation(DataRefImpl Ref) const; 247 uint32_t getSymbolSectionIdImpl(const WasmSymbol &Symb) const; 248 249 Error parseSection(WasmSection &Sec); 250 Error parseCustomSection(WasmSection &Sec, ReadContext &Ctx); 251 252 // Standard section types 253 Error parseTypeSection(ReadContext &Ctx); 254 Error parseImportSection(ReadContext &Ctx); 255 Error parseFunctionSection(ReadContext &Ctx); 256 Error parseTableSection(ReadContext &Ctx); 257 Error parseMemorySection(ReadContext &Ctx); 258 Error parseTagSection(ReadContext &Ctx); 259 Error parseGlobalSection(ReadContext &Ctx); 260 Error parseExportSection(ReadContext &Ctx); 261 Error parseStartSection(ReadContext &Ctx); 262 Error parseElemSection(ReadContext &Ctx); 263 Error parseCodeSection(ReadContext &Ctx); 264 Error parseDataSection(ReadContext &Ctx); 265 Error parseDataCountSection(ReadContext &Ctx); 266 267 // Custom section types 268 Error parseDylinkSection(ReadContext &Ctx); 269 Error parseDylink0Section(ReadContext &Ctx); 270 Error parseNameSection(ReadContext &Ctx); 271 Error parseLinkingSection(ReadContext &Ctx); 272 Error parseLinkingSectionSymtab(ReadContext &Ctx); 273 Error parseLinkingSectionComdat(ReadContext &Ctx); 274 Error parseProducersSection(ReadContext &Ctx); 275 Error parseTargetFeaturesSection(ReadContext &Ctx); 276 Error parseRelocSection(StringRef Name, ReadContext &Ctx); 277 278 wasm::WasmObjectHeader Header; 279 std::vector<WasmSection> Sections; 280 wasm::WasmDylinkInfo DylinkInfo; 281 wasm::WasmProducerInfo ProducerInfo; 282 std::vector<wasm::WasmFeatureEntry> TargetFeatures; 283 std::vector<wasm::WasmSignature> Signatures; 284 std::vector<wasm::WasmTable> Tables; 285 std::vector<wasm::WasmLimits> Memories; 286 std::vector<wasm::WasmGlobal> Globals; 287 std::vector<wasm::WasmTag> Tags; 288 std::vector<wasm::WasmImport> Imports; 289 std::vector<wasm::WasmExport> Exports; 290 std::vector<wasm::WasmElemSegment> ElemSegments; 291 std::vector<WasmSegment> DataSegments; 292 std::optional<size_t> DataCount; 293 std::vector<wasm::WasmFunction> Functions; 294 std::vector<WasmSymbol> Symbols; 295 std::vector<wasm::WasmDebugName> DebugNames; 296 uint32_t StartFunction = -1; 297 bool HasLinkingSection = false; 298 bool HasDylinkSection = false; 299 bool HasMemory64 = false; 300 bool HasUnmodeledTypes = false; 301 wasm::WasmLinkingData LinkingData; 302 uint32_t NumImportedGlobals = 0; 303 uint32_t NumImportedTables = 0; 304 uint32_t NumImportedFunctions = 0; 305 uint32_t NumImportedTags = 0; 306 uint32_t CodeSection = 0; 307 uint32_t DataSection = 0; 308 uint32_t TagSection = 0; 309 uint32_t GlobalSection = 0; 310 uint32_t TableSection = 0; 311 }; 312 313 class WasmSectionOrderChecker { 314 public: 315 // We define orders for all core wasm sections and known custom sections. 316 enum : int { 317 // Sentinel, must be zero 318 WASM_SEC_ORDER_NONE = 0, 319 320 // Core sections 321 WASM_SEC_ORDER_TYPE, 322 WASM_SEC_ORDER_IMPORT, 323 WASM_SEC_ORDER_FUNCTION, 324 WASM_SEC_ORDER_TABLE, 325 WASM_SEC_ORDER_MEMORY, 326 WASM_SEC_ORDER_TAG, 327 WASM_SEC_ORDER_GLOBAL, 328 WASM_SEC_ORDER_EXPORT, 329 WASM_SEC_ORDER_START, 330 WASM_SEC_ORDER_ELEM, 331 WASM_SEC_ORDER_DATACOUNT, 332 WASM_SEC_ORDER_CODE, 333 WASM_SEC_ORDER_DATA, 334 335 // Custom sections 336 // "dylink" should be the very first section in the module 337 WASM_SEC_ORDER_DYLINK, 338 // "linking" section requires DATA section in order to validate data symbols 339 WASM_SEC_ORDER_LINKING, 340 // Must come after "linking" section in order to validate reloc indexes. 341 WASM_SEC_ORDER_RELOC, 342 // "name" section must appear after DATA. Comes after "linking" to allow 343 // symbol table to set default function name. 344 WASM_SEC_ORDER_NAME, 345 // "producers" section must appear after "name" section. 346 WASM_SEC_ORDER_PRODUCERS, 347 // "target_features" section must appear after producers section 348 WASM_SEC_ORDER_TARGET_FEATURES, 349 350 // Must be last 351 WASM_NUM_SEC_ORDERS 352 353 }; 354 355 // Sections that may or may not be present, but cannot be predecessors 356 static int DisallowedPredecessors[WASM_NUM_SEC_ORDERS][WASM_NUM_SEC_ORDERS]; 357 358 bool isValidSectionOrder(unsigned ID, StringRef CustomSectionName = ""); 359 360 private: 361 bool Seen[WASM_NUM_SEC_ORDERS] = {}; // Sections that have been seen already 362 363 // Returns -1 for unknown sections. 364 int getSectionOrder(unsigned ID, StringRef CustomSectionName = ""); 365 }; 366 367 } // end namespace object 368 369 inline raw_ostream &operator<<(raw_ostream &OS, const object::WasmSymbol &Sym) { 370 Sym.print(OS); 371 return OS; 372 } 373 374 } // end namespace llvm 375 376 #endif // LLVM_OBJECT_WASM_H 377