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