1//===--- HeaderIncludes.cpp - Generate Header Includes --------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#include "clang/Frontend/Utils.h"
11#include "clang/Basic/SourceManager.h"
12#include "clang/Frontend/FrontendDiagnostic.h"
13#include "clang/Lex/Preprocessor.h"
14#include "llvm/ADT/SmallString.h"
15#include "llvm/Support/raw_ostream.h"
16using namespace clang;
17
18namespace {
19class HeaderIncludesCallback : public PPCallbacks {
20  SourceManager &SM;
21  raw_ostream *OutputFile;
22  unsigned CurrentIncludeDepth;
23  bool HasProcessedPredefines;
24  bool OwnsOutputFile;
25  bool ShowAllHeaders;
26  bool ShowDepth;
27  bool MSStyle;
28
29public:
30  HeaderIncludesCallback(const Preprocessor *PP, bool ShowAllHeaders_,
31                         raw_ostream *OutputFile_, bool OwnsOutputFile_,
32                         bool ShowDepth_, bool MSStyle_)
33    : SM(PP->getSourceManager()), OutputFile(OutputFile_),
34      CurrentIncludeDepth(0), HasProcessedPredefines(false),
35      OwnsOutputFile(OwnsOutputFile_), ShowAllHeaders(ShowAllHeaders_),
36      ShowDepth(ShowDepth_), MSStyle(MSStyle_) {}
37
38  ~HeaderIncludesCallback() override {
39    if (OwnsOutputFile)
40      delete OutputFile;
41  }
42
43  void FileChanged(SourceLocation Loc, FileChangeReason Reason,
44                   SrcMgr::CharacteristicKind FileType,
45                   FileID PrevFID) override;
46};
47}
48
49void clang::AttachHeaderIncludeGen(Preprocessor &PP, bool ShowAllHeaders,
50                                   StringRef OutputPath, bool ShowDepth,
51                                   bool MSStyle) {
52  raw_ostream *OutputFile = MSStyle ? &llvm::outs() : &llvm::errs();
53  bool OwnsOutputFile = false;
54
55  // Open the output file, if used.
56  if (!OutputPath.empty()) {
57    std::error_code EC;
58    llvm::raw_fd_ostream *OS = new llvm::raw_fd_ostream(
59        OutputPath.str(), EC, llvm::sys::fs::F_Append | llvm::sys::fs::F_Text);
60    if (EC) {
61      PP.getDiagnostics().Report(clang::diag::warn_fe_cc_print_header_failure)
62          << EC.message();
63      delete OS;
64    } else {
65      OS->SetUnbuffered();
66      OS->SetUseAtomicWrites(true);
67      OutputFile = OS;
68      OwnsOutputFile = true;
69    }
70  }
71
72  PP.addPPCallbacks(llvm::make_unique<HeaderIncludesCallback>(&PP,
73                                                              ShowAllHeaders,
74                                                              OutputFile,
75                                                              OwnsOutputFile,
76                                                              ShowDepth,
77                                                              MSStyle));
78}
79
80void HeaderIncludesCallback::FileChanged(SourceLocation Loc,
81                                         FileChangeReason Reason,
82                                       SrcMgr::CharacteristicKind NewFileType,
83                                       FileID PrevFID) {
84  // Unless we are exiting a #include, make sure to skip ahead to the line the
85  // #include directive was at.
86  PresumedLoc UserLoc = SM.getPresumedLoc(Loc);
87  if (UserLoc.isInvalid())
88    return;
89
90  // Adjust the current include depth.
91  if (Reason == PPCallbacks::EnterFile) {
92    ++CurrentIncludeDepth;
93  } else if (Reason == PPCallbacks::ExitFile) {
94    if (CurrentIncludeDepth)
95      --CurrentIncludeDepth;
96
97    // We track when we are done with the predefines by watching for the first
98    // place where we drop back to a nesting depth of 1.
99    if (CurrentIncludeDepth == 1 && !HasProcessedPredefines)
100      HasProcessedPredefines = true;
101
102    return;
103  } else
104    return;
105
106  // Show the header if we are (a) past the predefines, or (b) showing all
107  // headers and in the predefines at a depth past the initial file and command
108  // line buffers.
109  bool ShowHeader = (HasProcessedPredefines ||
110                     (ShowAllHeaders && CurrentIncludeDepth > 2));
111
112  // Dump the header include information we are past the predefines buffer or
113  // are showing all headers.
114  if (ShowHeader && Reason == PPCallbacks::EnterFile) {
115    // Write to a temporary string to avoid unnecessary flushing on errs().
116    SmallString<512> Filename(UserLoc.getFilename());
117    if (!MSStyle)
118      Lexer::Stringify(Filename);
119
120    SmallString<256> Msg;
121    if (MSStyle)
122      Msg += "Note: including file:";
123
124    if (ShowDepth) {
125      // The main source file is at depth 1, so skip one dot.
126      for (unsigned i = 1; i != CurrentIncludeDepth; ++i)
127        Msg += MSStyle ? ' ' : '.';
128
129      if (!MSStyle)
130        Msg += ' ';
131    }
132    Msg += Filename;
133    Msg += '\n';
134
135    OutputFile->write(Msg.data(), Msg.size());
136    OutputFile->flush();
137  }
138}
139