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