llvm-project/lld/lib/ReaderWriter/CoreLinkingContext.cpp

//===- lib/ReaderWriter/CoreLinkingContext.cpp ----------------------------===//
//
//                             The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "lld/Core/DefinedAtom.h"
#include "lld/Core/File.h"
#include "lld/Core/Pass.h"
#include "lld/Core/PassManager.h"
#include "lld/Core/Simple.h"
#include "lld/ReaderWriter/CoreLinkingContext.h"
#include "llvm/ADT/ArrayRef.h"

using namespace lld;

namespace {

/// \brief Simple atom created by the stubs pass.
class TestingStubAtom : public DefinedAtom {
public:
  TestingStubAtom(const File &F, const Atom &) : _file(F) {
    static uint32_t lastOrdinal = 0;
    _ordinal = lastOrdinal++;
  }

  const File &file() const override { return _file; }

  StringRef name() const override { return StringRef(); }

  uint64_t ordinal() const override { return _ordinal; }

  uint64_t size() const override { return 0; }

  Scope scope() const override { return DefinedAtom::scopeLinkageUnit; }

  Interposable interposable() const override { return DefinedAtom::interposeNo; }

  Merge merge() const override { return DefinedAtom::mergeNo; }

  ContentType contentType() const override { return DefinedAtom::typeStub; }

  Alignment alignment() const override { return 1; }

  SectionChoice sectionChoice() const override {
    return DefinedAtom::sectionBasedOnContent;
  }

  StringRef customSectionName() const override { return StringRef(); }

  DeadStripKind deadStrip() const override {
    return DefinedAtom::deadStripNormal;
  }

  ContentPermissions permissions() const override {
    return DefinedAtom::permR_X;
  }

  ArrayRef<uint8_t> rawContent() const override { return ArrayRef<uint8_t>(); }

  reference_iterator begin() const override {
    return reference_iterator(*this, nullptr);
  }

  reference_iterator end() const override {
    return reference_iterator(*this, nullptr);
  }

  const Reference *derefIterator(const void *iter) const override {
    return nullptr;
  }

  void incrementIterator(const void *&iter) const override {}

private:
  const File &_file;
  uint32_t _ordinal;
};

/// \brief Simple atom created by the GOT pass.
class TestingGOTAtom : public DefinedAtom {
public:
  TestingGOTAtom(const File &F, const Atom &) : _file(F) {
    static uint32_t lastOrdinal = 0;
    _ordinal = lastOrdinal++;
  }

  const File &file() const override { return _file; }

  StringRef name() const override { return StringRef(); }

  uint64_t ordinal() const override { return _ordinal; }

  uint64_t size() const override { return 0; }

  Scope scope() const override { return DefinedAtom::scopeLinkageUnit; }

  Interposable interposable() const override { return DefinedAtom::interposeNo; }

  Merge merge() const override { return DefinedAtom::mergeNo; }

  ContentType contentType() const override { return DefinedAtom::typeGOT; }

  Alignment alignment() const override { return 8; }

  SectionChoice sectionChoice() const override {
    return DefinedAtom::sectionBasedOnContent;
  }

  StringRef customSectionName() const override { return StringRef(); }

  DeadStripKind deadStrip() const override {
    return DefinedAtom::deadStripNormal;
  }

  ContentPermissions permissions() const override {
    return DefinedAtom::permRW_;
  }

  ArrayRef<uint8_t> rawContent() const override { return ArrayRef<uint8_t>(); }

  reference_iterator begin() const override {
    return reference_iterator(*this, nullptr);
  }

  reference_iterator end() const override {
    return reference_iterator(*this, nullptr);
  }

  const Reference *derefIterator(const void *iter) const override {
    return nullptr;
  }

  void incrementIterator(const void *&iter) const override {}

private:
  const File &_file;
  uint32_t _ordinal;
};

class OrderPass : public Pass {
public:
  /// Sorts atoms by position
  void perform(std::unique_ptr<MutableFile> &file) override {
    MutableFile::DefinedAtomRange defined = file->definedAtoms();
    std::sort(defined.begin(), defined.end(), DefinedAtom::compareByPosition);
  }
};

} // anonymous namespace

CoreLinkingContext::CoreLinkingContext() {}

bool CoreLinkingContext::validateImpl(raw_ostream &) {
  _writer = createWriterYAML(*this);
  return true;
}

void CoreLinkingContext::addPasses(PassManager &pm) {
  for (StringRef name : _passNames) {
    if (name.equals("order"))
      pm.add(std::unique_ptr<Pass>(new OrderPass()));
    else
      llvm_unreachable("bad pass name");
  }
}

Writer &CoreLinkingContext::writer() const { return *_writer; }