lld/ELF/LTO.h

   1 //===- LTO.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 // This file provides a way to combine bitcode files into one ELF
  10 // file by compiling them using LLVM.
  11 //
  12 // If LTO is in use, your input files are not in regular ELF files
  13 // but instead LLVM bitcode files. In that case, the linker has to
  14 // convert bitcode files into the native format so that we can create
  15 // an ELF file that contains native code. This file provides that
  16 // functionality.
  17 //
  18 //===----------------------------------------------------------------------===//
  19
  20 #ifndef LLD_ELF_LTO_H
  21 #define LLD_ELF_LTO_H
  22
  23 #include "lld/Common/LLVM.h"
  24 #include "llvm/ADT/DenseSet.h"
  25 #include "llvm/ADT/SmallString.h"
  26 #include "llvm/Support/raw_ostream.h"
  27 #include <memory>
  28 #include <vector>
  29
  30 namespace llvm::lto {
  31 class LTO;
  32 }
  33
  34 namespace lld::elf {
  35
  36 class BitcodeFile;
  37 class InputFile;
  38
  39 class BitcodeCompiler {
  40 public:
  41   BitcodeCompiler();
  42   ~BitcodeCompiler();
  43
  44   void add(BitcodeFile &f);
  45   std::vector<InputFile *> compile();
  46
  47 private:
  48   std::unique_ptr<llvm::lto::LTO> ltoObj;
  49   // An array of (module name, native relocatable file content) pairs.
  50   SmallVector<std::pair<std::string, SmallString<0>>, 0> buf;
  51   std::vector<std::unique_ptr<MemoryBuffer>> files;
  52   SmallVector<std::string, 0> filenames;
  53   llvm::DenseSet<StringRef> usedStartStop;
  54   std::unique_ptr<llvm::raw_fd_ostream> indexFile;
  55   llvm::DenseSet<StringRef> thinIndices;
  56 };
  57 } // namespace lld::elf
  58
  59 #endif