HeaderIncludeGen.cpp revision 221345 
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/Support/raw_ostream.h"
15using namespace clang;
16
17namespace {
18class HeaderIncludesCallback : public PPCallbacks {
19  SourceManager &SM;
20  llvm::raw_ostream *OutputFile;
21  unsigned CurrentIncludeDepth;
22  bool HasProcessedPredefines;
23  bool OwnsOutputFile;
24  bool ShowAllHeaders;
25  bool ShowDepth;
26
27public:
28  HeaderIncludesCallback(const Preprocessor *PP, bool ShowAllHeaders_,
29                         llvm::raw_ostream *OutputFile_, bool OwnsOutputFile_,
30                         bool ShowDepth_)
31    : SM(PP->getSourceManager()), OutputFile(OutputFile_),
32      CurrentIncludeDepth(0), HasProcessedPredefines(false),
33      OwnsOutputFile(OwnsOutputFile_), ShowAllHeaders(ShowAllHeaders_),
34      ShowDepth(ShowDepth_) {}
35
36  ~HeaderIncludesCallback() {
37    if (OwnsOutputFile)
38      delete OutputFile;
39  }
40
41  virtual void FileChanged(SourceLocation Loc, FileChangeReason Reason,
42                           SrcMgr::CharacteristicKind FileType);
43};
44}
45
46void clang::AttachHeaderIncludeGen(Preprocessor &PP, bool ShowAllHeaders,
47                                   llvm::StringRef OutputPath, bool ShowDepth) {
48  llvm::raw_ostream *OutputFile = &llvm::errs();
49  bool OwnsOutputFile = false;
50
51  // Open the output file, if used.
52  if (!OutputPath.empty()) {
53    std::string Error;
54    llvm::raw_fd_ostream *OS = new llvm::raw_fd_ostream(
55      OutputPath.str().c_str(), Error, llvm::raw_fd_ostream::F_Append);
56    if (!Error.empty()) {
57      PP.getDiagnostics().Report(
58        clang::diag::warn_fe_cc_print_header_failure) << Error;
59      delete OS;
60    } else {
61      OS->SetUnbuffered();
62      OS->SetUseAtomicWrites(true);
63      OutputFile = OS;
64      OwnsOutputFile = true;
65    }
66  }
67
68  PP.addPPCallbacks(new HeaderIncludesCallback(&PP, ShowAllHeaders,
69                                               OutputFile, OwnsOutputFile,
70                                               ShowDepth));
71}
72
73void HeaderIncludesCallback::FileChanged(SourceLocation Loc,
74                                         FileChangeReason Reason,
75                                       SrcMgr::CharacteristicKind NewFileType) {
76  // Unless we are exiting a #include, make sure to skip ahead to the line the
77  // #include directive was at.
78  PresumedLoc UserLoc = SM.getPresumedLoc(Loc);
79  if (UserLoc.isInvalid())
80    return;
81
82  // Adjust the current include depth.
83  if (Reason == PPCallbacks::EnterFile) {
84    ++CurrentIncludeDepth;
85  } else if (Reason == PPCallbacks::ExitFile) {
86    if (CurrentIncludeDepth)
87      --CurrentIncludeDepth;
88
89    // We track when we are done with the predefines by watching for the first
90    // place where we drop back to a nesting depth of 1.
91    if (CurrentIncludeDepth == 1 && !HasProcessedPredefines)
92      HasProcessedPredefines = true;
93
94    return;
95  } else
96    return;
97
98  // Show the header if we are (a) past the predefines, or (b) showing all
99  // headers and in the predefines at a depth past the initial file and command
100  // line buffers.
101  bool ShowHeader = (HasProcessedPredefines ||
102                     (ShowAllHeaders && CurrentIncludeDepth > 2));
103
104  // Dump the header include information we are past the predefines buffer or
105  // are showing all headers.
106  if (ShowHeader && Reason == PPCallbacks::EnterFile) {
107    // Write to a temporary string to avoid unnecessary flushing on errs().
108    llvm::SmallString<512> Filename(UserLoc.getFilename());
109    Lexer::Stringify(Filename);
110
111    llvm::SmallString<256> Msg;
112    if (ShowDepth) {
113      // The main source file is at depth 1, so skip one dot.
114      for (unsigned i = 1; i != CurrentIncludeDepth; ++i)
115        Msg += '.';
116      Msg += ' ';
117    }
118    Msg += Filename;
119    Msg += '\n';
120
121    OutputFile->write(Msg.data(), Msg.size());
122  }
123}
124