HeaderIncludeGen.cpp revision 263508 
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  virtual void FileChanged(SourceLocation Loc, FileChangeReason Reason,
44                           SrcMgr::CharacteristicKind FileType,
45                           FileID PrevFID);
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, llvm::sys::fs::F_Append);
60    if (!Error.empty()) {
61      PP.getDiagnostics().Report(
62        clang::diag::warn_fe_cc_print_header_failure) << Error;
63      delete OS;
64    } else {
65      OS->SetUnbuffered();
66      OS->SetUseAtomicWrites(true);
67      OutputFile = OS;
68      OwnsOutputFile = true;
69    }
70  }
71
72  PP.addPPCallbacks(new HeaderIncludesCallback(&PP, ShowAllHeaders,
73                                               OutputFile, OwnsOutputFile,
74                                               ShowDepth, MSStyle));
75}
76
77void HeaderIncludesCallback::FileChanged(SourceLocation Loc,
78                                         FileChangeReason Reason,
79                                       SrcMgr::CharacteristicKind NewFileType,
80                                       FileID PrevFID) {
81  // Unless we are exiting a #include, make sure to skip ahead to the line the
82  // #include directive was at.
83  PresumedLoc UserLoc = SM.getPresumedLoc(Loc);
84  if (UserLoc.isInvalid())
85    return;
86
87  // Adjust the current include depth.
88  if (Reason == PPCallbacks::EnterFile) {
89    ++CurrentIncludeDepth;
90  } else if (Reason == PPCallbacks::ExitFile) {
91    if (CurrentIncludeDepth)
92      --CurrentIncludeDepth;
93
94    // We track when we are done with the predefines by watching for the first
95    // place where we drop back to a nesting depth of 1.
96    if (CurrentIncludeDepth == 1 && !HasProcessedPredefines)
97      HasProcessedPredefines = true;
98
99    return;
100  } else
101    return;
102
103  // Show the header if we are (a) past the predefines, or (b) showing all
104  // headers and in the predefines at a depth past the initial file and command
105  // line buffers.
106  bool ShowHeader = (HasProcessedPredefines ||
107                     (ShowAllHeaders && CurrentIncludeDepth > 2));
108
109  // Dump the header include information we are past the predefines buffer or
110  // are showing all headers.
111  if (ShowHeader && Reason == PPCallbacks::EnterFile) {
112    // Write to a temporary string to avoid unnecessary flushing on errs().
113    SmallString<512> Filename(UserLoc.getFilename());
114    if (!MSStyle)
115      Lexer::Stringify(Filename);
116
117    SmallString<256> Msg;
118    if (MSStyle)
119      Msg += "Note: including file:";
120
121    if (ShowDepth) {
122      // The main source file is at depth 1, so skip one dot.
123      for (unsigned i = 1; i != CurrentIncludeDepth; ++i)
124        Msg += MSStyle ? ' ' : '.';
125
126      if (!MSStyle)
127        Msg += ' ';
128    }
129    Msg += Filename;
130    Msg += '\n';
131
132    OutputFile->write(Msg.data(), Msg.size());
133  }
134}
135