1//===- lib/ReaderWriter/MachO/WriterMachO.cpp -----------------------------===//
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#include "ExecutableAtoms.h"
10#include "MachONormalizedFile.h"
11#include "lld/Core/File.h"
12#include "lld/Core/Writer.h"
13#include "lld/ReaderWriter/MachOLinkingContext.h"
14#include "llvm/BinaryFormat/MachO.h"
15#include "llvm/Support/Debug.h"
16#include "llvm/Support/ErrorHandling.h"
17#include "llvm/Support/FileOutputBuffer.h"
18#include "llvm/Support/raw_ostream.h"
19#include <system_error>
20
21using lld::mach_o::normalized::NormalizedFile;
22
23namespace lld {
24namespace mach_o {
25
26class MachOWriter : public Writer {
27public:
28  MachOWriter(const MachOLinkingContext &ctxt) : _ctx(ctxt) {}
29
30  llvm::Error writeFile(const lld::File &file, StringRef path) override {
31    // Construct empty normalized file from atoms.
32    llvm::Expected<std::unique_ptr<NormalizedFile>> nFile =
33        normalized::normalizedFromAtoms(file, _ctx);
34    if (auto ec = nFile.takeError())
35      return ec;
36
37    // For testing, write out yaml form of normalized file.
38    if (_ctx.printAtoms()) {
39      std::unique_ptr<Writer> yamlWriter = createWriterYAML(_ctx);
40      if (auto ec = yamlWriter->writeFile(file, "-"))
41        return ec;
42    }
43
44    // Write normalized file as mach-o binary.
45    return writeBinary(*nFile->get(), path);
46  }
47
48  void createImplicitFiles(std::vector<std::unique_ptr<File>> &r) override {
49    // When building main executables, add _main as required entry point.
50    if (_ctx.outputTypeHasEntry())
51      r.emplace_back(new CEntryFile(_ctx));
52    // If this can link with dylibs, need helper function (dyld_stub_binder).
53    if (_ctx.needsStubsPass())
54      r.emplace_back(new StubHelperFile(_ctx));
55    // Final linked images can access a symbol for their mach_header.
56    if (_ctx.outputMachOType() != llvm::MachO::MH_OBJECT)
57      r.emplace_back(new MachHeaderAliasFile(_ctx));
58  }
59private:
60  const MachOLinkingContext &_ctx;
61 };
62
63
64} // namespace mach_o
65
66std::unique_ptr<Writer> createWriterMachO(const MachOLinkingContext &context) {
67  return std::unique_ptr<Writer>(new lld::mach_o::MachOWriter(context));
68}
69
70} // namespace lld
71