HeaderIncludeGen.cpp revision 651f13cea278ec967336033dd032faef0e9fc2ec 
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() {
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 = &llvm::errs();
53  bool OwnsOutputFile = false;
54
55  // Open the output file, if used.
56  if (!OutputPath.empty()) {
57    std::string Error;
58    llvm::raw_fd_ostream *OS = new llvm::raw_fd_ostream(
59        OutputPath.str().c_str(), Error,
60        llvm::sys::fs::F_Append | llvm::sys::fs::F_Text);
61    if (!Error.empty()) {
62      PP.getDiagnostics().Report(
63        clang::diag::warn_fe_cc_print_header_failure) << Error;
64      delete OS;
65    } else {
66      OS->SetUnbuffered();
67      OS->SetUseAtomicWrites(true);
68      OutputFile = OS;
69      OwnsOutputFile = true;
70    }
71  }
72
73  PP.addPPCallbacks(new HeaderIncludesCallback(&PP, ShowAllHeaders,
74                                               OutputFile, OwnsOutputFile,
75                                               ShowDepth, MSStyle));
76}
77
78void HeaderIncludesCallback::FileChanged(SourceLocation Loc,
79                                         FileChangeReason Reason,
80                                       SrcMgr::CharacteristicKind NewFileType,
81                                       FileID PrevFID) {
82  // Unless we are exiting a #include, make sure to skip ahead to the line the
83  // #include directive was at.
84  PresumedLoc UserLoc = SM.getPresumedLoc(Loc);
85  if (UserLoc.isInvalid())
86    return;
87
88  // Adjust the current include depth.
89  if (Reason == PPCallbacks::EnterFile) {
90    ++CurrentIncludeDepth;
91  } else if (Reason == PPCallbacks::ExitFile) {
92    if (CurrentIncludeDepth)
93      --CurrentIncludeDepth;
94
95    // We track when we are done with the predefines by watching for the first
96    // place where we drop back to a nesting depth of 1.
97    if (CurrentIncludeDepth == 1 && !HasProcessedPredefines)
98      HasProcessedPredefines = true;
99
100    return;
101  } else
102    return;
103
104  // Show the header if we are (a) past the predefines, or (b) showing all
105  // headers and in the predefines at a depth past the initial file and command
106  // line buffers.
107  bool ShowHeader = (HasProcessedPredefines ||
108                     (ShowAllHeaders && CurrentIncludeDepth > 2));
109
110  // Dump the header include information we are past the predefines buffer or
111  // are showing all headers.
112  if (ShowHeader && Reason == PPCallbacks::EnterFile) {
113    // Write to a temporary string to avoid unnecessary flushing on errs().
114    SmallString<512> Filename(UserLoc.getFilename());
115    if (!MSStyle)
116      Lexer::Stringify(Filename);
117
118    SmallString<256> Msg;
119    if (MSStyle)
120      Msg += "Note: including file:";
121
122    if (ShowDepth) {
123      // The main source file is at depth 1, so skip one dot.
124      for (unsigned i = 1; i != CurrentIncludeDepth; ++i)
125        Msg += MSStyle ? ' ' : '.';
126
127      if (!MSStyle)
128        Msg += ' ';
129    }
130    Msg += Filename;
131    Msg += '\n';
132
133    OutputFile->write(Msg.data(), Msg.size());
134  }
135}
136