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//===- Wasm.h - Wasm object file implementation -----------------*- C++ -*-===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

//

// This file declares the WasmObjectFile class, which implements the ObjectFile

// interface for Wasm files.

//

// See: https://github.com/WebAssembly/design/blob/main/BinaryEncoding.md

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_OBJECT_WASM_H

#define LLVM_OBJECT_WASM_H

#include "llvm/ADT/ArrayRef.h"

#include "llvm/ADT/StringRef.h"

#include "llvm/BinaryFormat/Wasm.h"

#include "llvm/Config/llvm-config.h"

#include "llvm/MC/MCSymbolWasm.h"

#include "llvm/Object/Binary.h"

#include "llvm/Object/ObjectFile.h"

#include "llvm/Support/Error.h"

#include "llvm/Support/MemoryBuffer.h"

#include <cstddef>

#include <cstdint>

#include <vector>

namespace llvm {

namespace object {

class WasmSymbol {

public:

  WasmSymbol(const wasm::WasmSymbolInfo &Info,

             const wasm::WasmGlobalType *GlobalType,

             const wasm::WasmTableType *TableType,

             const wasm::WasmSignature *Signature)

      : Info(Info), GlobalType(GlobalType), TableType(TableType),

        Signature(Signature) {}

  const wasm::WasmSymbolInfo &Info;

  const wasm::WasmGlobalType *GlobalType;

  const wasm::WasmTableType *TableType;

  const wasm::WasmSignature *Signature;

  bool isTypeFunction() const {

    return Info.Kind == wasm::WASM_SYMBOL_TYPE_FUNCTION;

  }

  bool isTypeTable() const { return Info.Kind == wasm::WASM_SYMBOL_TYPE_TABLE; }

  bool isTypeData() const { return Info.Kind == wasm::WASM_SYMBOL_TYPE_DATA; }

  bool isTypeGlobal() const {

    return Info.Kind == wasm::WASM_SYMBOL_TYPE_GLOBAL;

  }

  bool isTypeSection() const {

    return Info.Kind == wasm::WASM_SYMBOL_TYPE_SECTION;

  }

  bool isTypeTag() const { return Info.Kind == wasm::WASM_SYMBOL_TYPE_TAG; }

  bool isDefined() const { return !isUndefined(); }

  bool isUndefined() const {

    return (Info.Flags & wasm::WASM_SYMBOL_UNDEFINED) != 0;

  }

  bool isBindingWeak() const {

    return getBinding() == wasm::WASM_SYMBOL_BINDING_WEAK;

  }

  bool isBindingGlobal() const {

    return getBinding() == wasm::WASM_SYMBOL_BINDING_GLOBAL;

  }

  bool isBindingLocal() const {

    return getBinding() == wasm::WASM_SYMBOL_BINDING_LOCAL;

  }

  unsigned getBinding() const {

    return Info.Flags & wasm::WASM_SYMBOL_BINDING_MASK;

  }

  bool isHidden() const {

    return getVisibility() == wasm::WASM_SYMBOL_VISIBILITY_HIDDEN;

  }

  unsigned getVisibility() const {

    return Info.Flags & wasm::WASM_SYMBOL_VISIBILITY_MASK;

  }

  void print(raw_ostream &Out) const;

#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)

  LLVM_DUMP_METHOD void dump() const;

#endif

};

struct WasmSection {

  WasmSection() = default;

  uint32_t Type = 0;         // Section type (See below)

  uint32_t Offset = 0;       // Offset with in the file

  StringRef Name;            // Section name (User-defined sections only)

  uint32_t Comdat = UINT32_MAX; // From the "comdat info" section

  ArrayRef<uint8_t> Content; // Section content

  std::vector<wasm::WasmRelocation> Relocations; // Relocations for this section

};

struct WasmSegment {

  uint32_t SectionOffset;

  wasm::WasmDataSegment Data;

};

class WasmObjectFile : public ObjectFile {

public:

  WasmObjectFile(MemoryBufferRef Object, Error &Err);

  const wasm::WasmObjectHeader &getHeader() const;

  const WasmSymbol &getWasmSymbol(const DataRefImpl &Symb) const;

  const WasmSymbol &getWasmSymbol(const SymbolRef &Symbol) const;

  const WasmSection &getWasmSection(const SectionRef &Section) const;

  const wasm::WasmRelocation &getWasmRelocation(const RelocationRef &Ref) const;

  static bool classof(const Binary *v) { return v->isWasm(); }

  const wasm::WasmDylinkInfo &dylinkInfo() const { return DylinkInfo; }

  const wasm::WasmProducerInfo &getProducerInfo() const { return ProducerInfo; }

  ArrayRef<wasm::WasmFeatureEntry> getTargetFeatures() const {

    return TargetFeatures;

  }

  ArrayRef<wasm::WasmSignature> types() const { return Signatures; }

  ArrayRef<wasm::WasmImport> imports() const { return Imports; }

  ArrayRef<wasm::WasmTable> tables() const { return Tables; }

  ArrayRef<wasm::WasmLimits> memories() const { return Memories; }

  ArrayRef<wasm::WasmGlobal> globals() const { return Globals; }

  ArrayRef<wasm::WasmTag> tags() const { return Tags; }

  ArrayRef<wasm::WasmExport> exports() const { return Exports; }

  ArrayRef<WasmSymbol> syms() const { return Symbols; }

  const wasm::WasmLinkingData &linkingData() const { return LinkingData; }

  uint32_t getNumberOfSymbols() const { return Symbols.size(); }

  ArrayRef<wasm::WasmElemSegment> elements() const { return ElemSegments; }

  ArrayRef<WasmSegment> dataSegments() const { return DataSegments; }

  ArrayRef<wasm::WasmFunction> functions() const { return Functions; }

  ArrayRef<wasm::WasmDebugName> debugNames() const { return DebugNames; }

  uint32_t startFunction() const { return StartFunction; }

  uint32_t getNumImportedGlobals() const { return NumImportedGlobals; }

  uint32_t getNumImportedTables() const { return NumImportedTables; }

  uint32_t getNumImportedFunctions() const { return NumImportedFunctions; }

  uint32_t getNumImportedTags() const { return NumImportedTags; }

  uint32_t getNumSections() const { return Sections.size(); }

  void moveSymbolNext(DataRefImpl &Symb) const override;

  Expected<uint32_t> getSymbolFlags(DataRefImpl Symb) const override;

  basic_symbol_iterator symbol_begin() const override;

  basic_symbol_iterator symbol_end() const override;

  Expected<StringRef> getSymbolName(DataRefImpl Symb) const override;

  Expected<uint64_t> getSymbolAddress(DataRefImpl Symb) const override;

  uint64_t getWasmSymbolValue(const WasmSymbol &Sym) const;

  uint64_t getSymbolValueImpl(DataRefImpl Symb) const override;

  uint32_t getSymbolAlignment(DataRefImpl Symb) const override;

  uint64_t getCommonSymbolSizeImpl(DataRefImpl Symb) const override;

  Expected<SymbolRef::Type> getSymbolType(DataRefImpl Symb) const override;

  Expected<section_iterator> getSymbolSection(DataRefImpl Symb) const override;

  uint32_t getSymbolSectionId(SymbolRef Sym) const;

  // Overrides from SectionRef.

  void moveSectionNext(DataRefImpl &Sec) const override;

  Expected<StringRef> getSectionName(DataRefImpl Sec) const override;

  uint64_t getSectionAddress(DataRefImpl Sec) const override;

  uint64_t getSectionIndex(DataRefImpl Sec) const override;

  uint64_t getSectionSize(DataRefImpl Sec) const override;

  Expected<ArrayRef<uint8_t>>

  getSectionContents(DataRefImpl Sec) const override;

  uint64_t getSectionAlignment(DataRefImpl Sec) const override;

  bool isSectionCompressed(DataRefImpl Sec) const override;

  bool isSectionText(DataRefImpl Sec) const override;

  bool isSectionData(DataRefImpl Sec) const override;

  bool isSectionBSS(DataRefImpl Sec) const override;

  bool isSectionVirtual(DataRefImpl Sec) const override;

  relocation_iterator section_rel_begin(DataRefImpl Sec) const override;

  relocation_iterator section_rel_end(DataRefImpl Sec) const override;

  // Overrides from RelocationRef.

  void moveRelocationNext(DataRefImpl &Rel) const override;

  uint64_t getRelocationOffset(DataRefImpl Rel) const override;

  symbol_iterator getRelocationSymbol(DataRefImpl Rel) const override;

  uint64_t getRelocationType(DataRefImpl Rel) const override;

  void getRelocationTypeName(DataRefImpl Rel,

                             SmallVectorImpl<char> &Result) const override;

  section_iterator section_begin() const override;

  section_iterator section_end() const override;

  uint8_t getBytesInAddress() const override;

  StringRef getFileFormatName() const override;

  Triple::ArchType getArch() const override;

  Expected<SubtargetFeatures> getFeatures() const override;

  bool isRelocatableObject() const override;

  bool isSharedObject() const;

  struct ReadContext {

    const uint8_t *Start;

    const uint8_t *Ptr;

    const uint8_t *End;

  };

private:

  bool isValidFunctionIndex(uint32_t Index) const;

  bool isDefinedFunctionIndex(uint32_t Index) const;

  bool isValidGlobalIndex(uint32_t Index) const;

  bool isValidTableNumber(uint32_t Index) const;

  bool isDefinedGlobalIndex(uint32_t Index) const;

  bool isDefinedTableNumber(uint32_t Index) const;

  bool isValidTagIndex(uint32_t Index) const;

  bool isDefinedTagIndex(uint32_t Index) const;

  bool isValidFunctionSymbol(uint32_t Index) const;

  bool isValidTableSymbol(uint32_t Index) const;

  bool isValidGlobalSymbol(uint32_t Index) const;

  bool isValidTagSymbol(uint32_t Index) const;

  bool isValidDataSymbol(uint32_t Index) const;

  bool isValidSectionSymbol(uint32_t Index) const;

  wasm::WasmFunction &getDefinedFunction(uint32_t Index);

  const wasm::WasmFunction &getDefinedFunction(uint32_t Index) const;

  wasm::WasmGlobal &getDefinedGlobal(uint32_t Index);

  wasm::WasmTag &getDefinedTag(uint32_t Index);

  const WasmSection &getWasmSection(DataRefImpl Ref) const;

  const wasm::WasmRelocation &getWasmRelocation(DataRefImpl Ref) const;

  uint32_t getSymbolSectionIdImpl(const WasmSymbol &Symb) const;

  Error parseSection(WasmSection &Sec);

  Error parseCustomSection(WasmSection &Sec, ReadContext &Ctx);

  // Standard section types

  Error parseTypeSection(ReadContext &Ctx);

  Error parseImportSection(ReadContext &Ctx);

  Error parseFunctionSection(ReadContext &Ctx);

  Error parseTableSection(ReadContext &Ctx);

  Error parseMemorySection(ReadContext &Ctx);

  Error parseTagSection(ReadContext &Ctx);

  Error parseGlobalSection(ReadContext &Ctx);

  Error parseExportSection(ReadContext &Ctx);

  Error parseStartSection(ReadContext &Ctx);

  Error parseElemSection(ReadContext &Ctx);

  Error parseCodeSection(ReadContext &Ctx);

  Error parseDataSection(ReadContext &Ctx);

  Error parseDataCountSection(ReadContext &Ctx);

  // Custom section types

  Error parseDylinkSection(ReadContext &Ctx);

  Error parseDylink0Section(ReadContext &Ctx);

  Error parseNameSection(ReadContext &Ctx);

  Error parseLinkingSection(ReadContext &Ctx);

  Error parseLinkingSectionSymtab(ReadContext &Ctx);

  Error parseLinkingSectionComdat(ReadContext &Ctx);

  Error parseProducersSection(ReadContext &Ctx);

  Error parseTargetFeaturesSection(ReadContext &Ctx);

  Error parseRelocSection(StringRef Name, ReadContext &Ctx);

  wasm::WasmObjectHeader Header;

  std::vector<WasmSection> Sections;

  wasm::WasmDylinkInfo DylinkInfo;

  wasm::WasmProducerInfo ProducerInfo;

  std::vector<wasm::WasmFeatureEntry> TargetFeatures;

  std::vector<wasm::WasmSignature> Signatures;

  std::vector<wasm::WasmTable> Tables;

  std::vector<wasm::WasmLimits> Memories;

  std::vector<wasm::WasmGlobal> Globals;

  std::vector<wasm::WasmTag> Tags;

  std::vector<wasm::WasmImport> Imports;

  std::vector<wasm::WasmExport> Exports;

  std::vector<wasm::WasmElemSegment> ElemSegments;

  std::vector<WasmSegment> DataSegments;

  std::optional<size_t> DataCount;

  std::vector<wasm::WasmFunction> Functions;

  std::vector<WasmSymbol> Symbols;

  std::vector<wasm::WasmDebugName> DebugNames;

  uint32_t StartFunction = -1;

  bool HasLinkingSection = false;

  bool HasDylinkSection = false;

  bool HasMemory64 = false;

  wasm::WasmLinkingData LinkingData;

  uint32_t NumImportedGlobals = 0;

  uint32_t NumImportedTables = 0;

  uint32_t NumImportedFunctions = 0;

  uint32_t NumImportedTags = 0;

  uint32_t CodeSection = 0;

  uint32_t DataSection = 0;

  uint32_t TagSection = 0;

  uint32_t GlobalSection = 0;

  uint32_t TableSection = 0;

};

class WasmSectionOrderChecker {

public:

  // We define orders for all core wasm sections and known custom sections.

  enum : int {

    // Sentinel, must be zero

    WASM_SEC_ORDER_NONE = 0,

    // Core sections

    WASM_SEC_ORDER_TYPE,

    WASM_SEC_ORDER_IMPORT,

    WASM_SEC_ORDER_FUNCTION,

    WASM_SEC_ORDER_TABLE,

    WASM_SEC_ORDER_MEMORY,

    WASM_SEC_ORDER_TAG,

    WASM_SEC_ORDER_GLOBAL,

    WASM_SEC_ORDER_EXPORT,

    WASM_SEC_ORDER_START,

    WASM_SEC_ORDER_ELEM,

    WASM_SEC_ORDER_DATACOUNT,

    WASM_SEC_ORDER_CODE,

    WASM_SEC_ORDER_DATA,

    // Custom sections

    // "dylink" should be the very first section in the module

    WASM_SEC_ORDER_DYLINK,

    // "linking" section requires DATA section in order to validate data symbols

    WASM_SEC_ORDER_LINKING,

    // Must come after "linking" section in order to validate reloc indexes.

    WASM_SEC_ORDER_RELOC,

    // "name" section must appear after DATA. Comes after "linking" to allow

    // symbol table to set default function name.

    WASM_SEC_ORDER_NAME,

    // "producers" section must appear after "name" section.

    WASM_SEC_ORDER_PRODUCERS,

    // "target_features" section must appear after producers section

    WASM_SEC_ORDER_TARGET_FEATURES,

    // Must be last

    WASM_NUM_SEC_ORDERS

  };

  // Sections that may or may not be present, but cannot be predecessors

  static int DisallowedPredecessors[WASM_NUM_SEC_ORDERS][WASM_NUM_SEC_ORDERS];

  bool isValidSectionOrder(unsigned ID, StringRef CustomSectionName = "");

private:

  bool Seen[WASM_NUM_SEC_ORDERS] = {}; // Sections that have been seen already

  // Returns -1 for unknown sections.

  int getSectionOrder(unsigned ID, StringRef CustomSectionName = "");

};

} // end namespace object

inline raw_ostream &operator<<(raw_ostream &OS, const object::WasmSymbol &Sym) {

  Sym.print(OS);

  return OS;

}

} // end namespace llvm

#endif // LLVM_OBJECT_WASM_H