include/llvm/Object/Wasm.h

   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:
  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
  50   bool isTypeFunction() const {
  51     return Info.Kind == wasm::WASM_SYMBOL_TYPE_FUNCTION;
  52   }
  53
  54   bool isTypeData() const { return Info.Kind == wasm::WASM_SYMBOL_TYPE_DATA; }
  55
  56   bool isTypeGlobal() const {
  57     return Info.Kind == wasm::WASM_SYMBOL_TYPE_GLOBAL;
  58   }
  59
  60   bool isTypeSection() const {
  61     return Info.Kind == wasm::WASM_SYMBOL_TYPE_SECTION;
  62   }
  63
  64   bool isTypeEvent() const { return Info.Kind == wasm::WASM_SYMBOL_TYPE_EVENT; }
  65
  66   bool isDefined() const { return !isUndefined(); }
  67
  68   bool isUndefined() const {
  69     return (Info.Flags & wasm::WASM_SYMBOL_UNDEFINED) != 0;
  70   }
  71
  72   bool isBindingWeak() const {
  73     return getBinding() == wasm::WASM_SYMBOL_BINDING_WEAK;
  74   }
  75
  76   bool isBindingGlobal() const {
  77     return getBinding() == wasm::WASM_SYMBOL_BINDING_GLOBAL;
  78   }
  79
  80   bool isBindingLocal() const {
  81     return getBinding() == wasm::WASM_SYMBOL_BINDING_LOCAL;
  82   }
  83
  84   unsigned getBinding() const {
  85     return Info.Flags & wasm::WASM_SYMBOL_BINDING_MASK;
  86   }
  87
  88   bool isHidden() const {
  89     return getVisibility() == wasm::WASM_SYMBOL_VISIBILITY_HIDDEN;
  90   }
  91
  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
 129   static bool classof(const Binary *v) { return v->isWasm(); }
 130
 131   const wasm::WasmDylinkInfo &dylinkInfo() const { return DylinkInfo; }
 132   const wasm::WasmProducerInfo &getProducerInfo() const { return ProducerInfo; }
 133   ArrayRef<wasm::WasmFeatureEntry> getTargetFeatures() const {
 134     return TargetFeatures;
 135   }
 136   ArrayRef<wasm::WasmSignature> types() const { return Signatures; }
 137   ArrayRef<uint32_t> functionTypes() const { return FunctionTypes; }
 138   ArrayRef<wasm::WasmImport> imports() const { return Imports; }
 139   ArrayRef<wasm::WasmTable> tables() const { return Tables; }
 140   ArrayRef<wasm::WasmLimits> memories() const { return Memories; }
 141   ArrayRef<wasm::WasmGlobal> globals() const { return Globals; }
 142   ArrayRef<wasm::WasmEvent> events() const { return Events; }
 143   ArrayRef<wasm::WasmExport> exports() const { return Exports; }
 144   ArrayRef<WasmSymbol> syms() const { return Symbols; }
 145   const wasm::WasmLinkingData &linkingData() const { return LinkingData; }
 146   uint32_t getNumberOfSymbols() const { return Symbols.size(); }
 147   ArrayRef<wasm::WasmElemSegment> elements() const { return ElemSegments; }
 148   ArrayRef<WasmSegment> dataSegments() const { return DataSegments; }
 149   ArrayRef<wasm::WasmFunction> functions() const { return Functions; }
 150   ArrayRef<wasm::WasmFunctionName> debugNames() const { return DebugNames; }
 151   uint32_t startFunction() const { return StartFunction; }
 152   uint32_t getNumImportedGlobals() const { return NumImportedGlobals; }
 153   uint32_t getNumImportedFunctions() const { return NumImportedFunctions; }
 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   wasm::WasmLinkingData LinkingData;
 284   uint32_t NumImportedGlobals = 0;
 285   uint32_t NumImportedFunctions = 0;
 286   uint32_t NumImportedEvents = 0;
 287   uint32_t CodeSection = 0;
 288   uint32_t DataSection = 0;
 289   uint32_t GlobalSection = 0;
 290   uint32_t EventSection = 0;
 291 };
 292
 293 class WasmSectionOrderChecker {
 294 public:
 295   // We define orders for all core wasm sections and known custom sections.
 296   enum : int {
 297     // Sentinel, must be zero
 298     WASM_SEC_ORDER_NONE = 0,
 299
 300     // Core sections
 301     WASM_SEC_ORDER_TYPE,
 302     WASM_SEC_ORDER_IMPORT,
 303     WASM_SEC_ORDER_FUNCTION,
 304     WASM_SEC_ORDER_TABLE,
 305     WASM_SEC_ORDER_MEMORY,
 306     WASM_SEC_ORDER_GLOBAL,
 307     WASM_SEC_ORDER_EVENT,
 308     WASM_SEC_ORDER_EXPORT,
 309     WASM_SEC_ORDER_START,
 310     WASM_SEC_ORDER_ELEM,
 311     WASM_SEC_ORDER_DATACOUNT,
 312     WASM_SEC_ORDER_CODE,
 313     WASM_SEC_ORDER_DATA,
 314
 315     // Custom sections
 316     // "dylink" should be the very first section in the module
 317     WASM_SEC_ORDER_DYLINK,
 318     // "linking" section requires DATA section in order to validate data symbols
 319     WASM_SEC_ORDER_LINKING,
 320     // Must come after "linking" section in order to validate reloc indexes.
 321     WASM_SEC_ORDER_RELOC,
 322     // "name" section must appear after DATA. Comes after "linking" to allow
 323     // symbol table to set default function name.
 324     WASM_SEC_ORDER_NAME,
 325     // "producers" section must appear after "name" section.
 326     WASM_SEC_ORDER_PRODUCERS,
 327     // "target_features" section must appear after producers section
 328     WASM_SEC_ORDER_TARGET_FEATURES,
 329
 330     // Must be last
 331     WASM_NUM_SEC_ORDERS
 332
 333   };
 334
 335   // Sections that may or may not be present, but cannot be predecessors
 336   static int DisallowedPredecessors[WASM_NUM_SEC_ORDERS][WASM_NUM_SEC_ORDERS];
 337
 338   bool isValidSectionOrder(unsigned ID, StringRef CustomSectionName = "");
 339
 340 private:
 341   bool Seen[WASM_NUM_SEC_ORDERS] = {}; // Sections that have been seen already
 342
 343   // Returns -1 for unknown sections.
 344   int getSectionOrder(unsigned ID, StringRef CustomSectionName = "");
 345 };
 346
 347 } // end namespace object
 348
 349 inline raw_ostream &operator<<(raw_ostream &OS, const object::WasmSymbol &Sym) {
 350   Sym.print(OS);
 351   return OS;
 352 }
 353
 354 } // end namespace llvm
 355
 356 #endif // LLVM_OBJECT_WASM_H