1//===-- DependencyInfo.h --------------------------------------------------===//
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 "llvm/ADT/StringRef.h"
10#include "llvm/Support/FileSystem.h"
11#include "llvm/Support/WithColor.h"
12#include "llvm/Support/raw_ostream.h"
13
14#include <set>
15
16class DependencyInfo {
17public:
18  explicit DependencyInfo(std::string DependencyInfoPath)
19      : DependencyInfoPath(DependencyInfoPath) {}
20
21  virtual ~DependencyInfo(){};
22
23  virtual void addMissingInput(llvm::StringRef Path) {
24    NotFounds.insert(Path.str());
25  }
26
27  // Writes the dependencies to specified path. The content is first sorted by
28  // OpCode and then by the filename (in alphabetical order).
29  virtual void write(llvm::Twine Version,
30                     const std::vector<std::string> &Inputs,
31                     std::string Output) {
32    std::error_code EC;
33    llvm::raw_fd_ostream OS(DependencyInfoPath, EC, llvm::sys::fs::OF_None);
34    if (EC) {
35      llvm::WithColor::defaultErrorHandler(llvm::createStringError(
36          EC,
37          "failed to write to " + DependencyInfoPath + ": " + EC.message()));
38      return;
39    }
40
41    auto AddDep = [&OS](DependencyInfoOpcode Opcode,
42                        const llvm::StringRef &Path) {
43      OS << static_cast<uint8_t>(Opcode);
44      OS << Path;
45      OS << '\0';
46    };
47
48    AddDep(DependencyInfoOpcode::Tool, Version.str());
49
50    // Sort the input by its names.
51    std::vector<llvm::StringRef> InputNames;
52    InputNames.reserve(Inputs.size());
53    for (const auto &F : Inputs)
54      InputNames.push_back(F);
55    llvm::sort(InputNames);
56
57    for (const auto &In : InputNames)
58      AddDep(DependencyInfoOpcode::InputFound, In);
59
60    for (const std::string &F : NotFounds)
61      AddDep(DependencyInfoOpcode::InputMissing, F);
62
63    AddDep(DependencyInfoOpcode::Output, Output);
64  }
65
66private:
67  enum DependencyInfoOpcode : uint8_t {
68    Tool = 0x00,
69    InputFound = 0x10,
70    InputMissing = 0x11,
71    Output = 0x40,
72  };
73
74  const std::string DependencyInfoPath;
75  std::set<std::string> NotFounds;
76};
77
78// Subclass to avoid any overhead when not using this feature
79class DummyDependencyInfo : public DependencyInfo {
80public:
81  DummyDependencyInfo() : DependencyInfo("") {}
82  void addMissingInput(llvm::StringRef Path) override {}
83  void write(llvm::Twine Version, const std::vector<std::string> &Inputs,
84             std::string Output) override {}
85};
86