lld/wasm/InputFiles.h

   1 //===- InputFiles.h ---------------------------------------------*- 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 #ifndef LLD_WASM_INPUT_FILES_H
  10 #define LLD_WASM_INPUT_FILES_H
  11
  12 #include "Symbols.h"
  13 #include "lld/Common/LLVM.h"
  14 #include "llvm/ADT/DenseMap.h"
  15 #include "llvm/ADT/DenseSet.h"
  16 #include "llvm/ADT/Triple.h"
  17 #include "llvm/LTO/LTO.h"
  18 #include "llvm/Object/Archive.h"
  19 #include "llvm/Object/Wasm.h"
  20 #include "llvm/Support/MemoryBuffer.h"
  21 #include <vector>
  22
  23 namespace llvm {
  24 class TarWriter;
  25 }
  26
  27 namespace lld {
  28 namespace wasm {
  29
  30 class InputChunk;
  31 class InputFunction;
  32 class InputSegment;
  33 class InputGlobal;
  34 class InputTag;
  35 class InputTable;
  36 class InputSection;
  37
  38 // If --reproduce option is given, all input files are written
  39 // to this tar archive.
  40 extern std::unique_ptr<llvm::TarWriter> tar;
  41
  42 class InputFile {
  43 public:
  44   enum Kind {
  45     ObjectKind,
  46     SharedKind,
  47     ArchiveKind,
  48     BitcodeKind,
  49   };
  50
  51   virtual ~InputFile() {}
  52
  53   // Returns the filename.
  54   StringRef getName() const { return mb.getBufferIdentifier(); }
  55
  56   Kind kind() const { return fileKind; }
  57
  58   // An archive file name if this file is created from an archive.
  59   std::string archiveName;
  60
  61   ArrayRef<Symbol *> getSymbols() const { return symbols; }
  62
  63   MutableArrayRef<Symbol *> getMutableSymbols() { return symbols; }
  64
  65   // An InputFile is considered live if any of the symbols defined by it
  66   // are live.
  67   void markLive() { live = true; }
  68   bool isLive() const { return live; }
  69
  70 protected:
  71   InputFile(Kind k, MemoryBufferRef m)
  72       : mb(m), fileKind(k), live(!config->gcSections) {}
  73
  74   void checkArch(llvm::Triple::ArchType arch) const;
  75
  76   MemoryBufferRef mb;
  77
  78   // List of all symbols referenced or defined by this file.
  79   std::vector<Symbol *> symbols;
  80
  81 private:
  82   const Kind fileKind;
  83   bool live;
  84 };
  85
  86 // .a file (ar archive)
  87 class ArchiveFile : public InputFile {
  88 public:
  89   explicit ArchiveFile(MemoryBufferRef m) : InputFile(ArchiveKind, m) {}
  90   static bool classof(const InputFile *f) { return f->kind() == ArchiveKind; }
  91
  92   void addMember(const llvm::object::Archive::Symbol *sym);
  93
  94   void parse();
  95
  96 private:
  97   std::unique_ptr<llvm::object::Archive> file;
  98   llvm::DenseSet<uint64_t> seen;
  99 };
 100
 101 // .o file (wasm object file)
 102 class ObjFile : public InputFile {
 103 public:
 104   explicit ObjFile(MemoryBufferRef m, StringRef archiveName)
 105       : InputFile(ObjectKind, m) {
 106     this->archiveName = std::string(archiveName);
 107
 108     // If this isn't part of an archive, it's eagerly linked, so mark it live.
 109     if (archiveName.empty())
 110       markLive();
 111   }
 112   static bool classof(const InputFile *f) { return f->kind() == ObjectKind; }
 113
 114   void parse(bool ignoreComdats = false);
 115
 116   // Returns the underlying wasm file.
 117   const WasmObjectFile *getWasmObj() const { return wasmObj.get(); }
 118
 119   uint32_t calcNewIndex(const WasmRelocation &reloc) const;
 120   uint64_t calcNewValue(const WasmRelocation &reloc, uint64_t tombstone,
 121                         const InputChunk *chunk) const;
 122   int64_t calcNewAddend(const WasmRelocation &reloc) const;
 123   Symbol *getSymbol(const WasmRelocation &reloc) const {
 124     return symbols[reloc.Index];
 125   };
 126
 127   const WasmSection *codeSection = nullptr;
 128   const WasmSection *dataSection = nullptr;
 129
 130   // Maps input type indices to output type indices
 131   std::vector<uint32_t> typeMap;
 132   std::vector<bool> typeIsUsed;
 133   // Maps function indices to table indices
 134   std::vector<uint32_t> tableEntries;
 135   std::vector<uint32_t> tableEntriesRel;
 136   std::vector<bool> keptComdats;
 137   std::vector<InputChunk *> segments;
 138   std::vector<InputFunction *> functions;
 139   std::vector<InputGlobal *> globals;
 140   std::vector<InputTag *> tags;
 141   std::vector<InputTable *> tables;
 142   std::vector<InputChunk *> customSections;
 143   llvm::DenseMap<uint32_t, InputChunk *> customSectionsByIndex;
 144
 145   Symbol *getSymbol(uint32_t index) const { return symbols[index]; }
 146   FunctionSymbol *getFunctionSymbol(uint32_t index) const;
 147   DataSymbol *getDataSymbol(uint32_t index) const;
 148   GlobalSymbol *getGlobalSymbol(uint32_t index) const;
 149   SectionSymbol *getSectionSymbol(uint32_t index) const;
 150   TagSymbol *getTagSymbol(uint32_t index) const;
 151   TableSymbol *getTableSymbol(uint32_t index) const;
 152
 153 private:
 154   Symbol *createDefined(const WasmSymbol &sym);
 155   Symbol *createUndefined(const WasmSymbol &sym, bool isCalledDirectly);
 156
 157   bool isExcludedByComdat(const InputChunk *chunk) const;
 158   void addLegacyIndirectFunctionTableIfNeeded(uint32_t tableSymbolCount);
 159
 160   std::unique_ptr<WasmObjectFile> wasmObj;
 161 };
 162
 163 // .so file.
 164 class SharedFile : public InputFile {
 165 public:
 166   explicit SharedFile(MemoryBufferRef m) : InputFile(SharedKind, m) {}
 167   static bool classof(const InputFile *f) { return f->kind() == SharedKind; }
 168 };
 169
 170 // .bc file
 171 class BitcodeFile : public InputFile {
 172 public:
 173   BitcodeFile(MemoryBufferRef m, StringRef archiveName,
 174               uint64_t offsetInArchive);
 175   static bool classof(const InputFile *f) { return f->kind() == BitcodeKind; }
 176
 177   void parse();
 178   std::unique_ptr<llvm::lto::InputFile> obj;
 179
 180   // Set to true once LTO is complete in order prevent further bitcode objects
 181   // being added.
 182   static bool doneLTO;
 183 };
 184
 185 inline bool isBitcode(MemoryBufferRef mb) {
 186   return identify_magic(mb.getBuffer()) == llvm::file_magic::bitcode;
 187 }
 188
 189 // Will report a fatal() error if the input buffer is not a valid bitcode
 190 // or wasm object file.
 191 InputFile *createObjectFile(MemoryBufferRef mb, StringRef archiveName = "",
 192                             uint64_t offsetInArchive = 0);
 193
 194 // Opens a given file.
 195 llvm::Optional<MemoryBufferRef> readFile(StringRef path);
 196
 197 } // namespace wasm
 198
 199 std::string toString(const wasm::InputFile *file);
 200
 201 } // namespace lld
 202
 203 #endif