HeaderIncludeGen.cpp revision c892c5fa92db137ff68d95afb13fe969d17f4fb2 
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  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                         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                           FileID PrevFID);
44};
45}
46
47void clang::AttachHeaderIncludeGen(Preprocessor &PP, bool ShowAllHeaders,
48                                   StringRef OutputPath, bool ShowDepth) {
49  raw_ostream *OutputFile = &llvm::errs();
50  bool OwnsOutputFile = false;
51
52  // Open the output file, if used.
53  if (!OutputPath.empty()) {
54    std::string Error;
55    llvm::raw_fd_ostream *OS = new llvm::raw_fd_ostream(
56      OutputPath.str().c_str(), Error, llvm::raw_fd_ostream::F_Append);
57    if (!Error.empty()) {
58      PP.getDiagnostics().Report(
59        clang::diag::warn_fe_cc_print_header_failure) << Error;
60      delete OS;
61    } else {
62      OS->SetUnbuffered();
63      OS->SetUseAtomicWrites(true);
64      OutputFile = OS;
65      OwnsOutputFile = true;
66    }
67  }
68
69  PP.addPPCallbacks(new HeaderIncludesCallback(&PP, ShowAllHeaders,
70                                               OutputFile, OwnsOutputFile,
71                                               ShowDepth));
72}
73
74void HeaderIncludesCallback::FileChanged(SourceLocation Loc,
75                                         FileChangeReason Reason,
76                                       SrcMgr::CharacteristicKind NewFileType,
77                                       FileID PrevFID) {
78  // Unless we are exiting a #include, make sure to skip ahead to the line the
79  // #include directive was at.
80  PresumedLoc UserLoc = SM.getPresumedLoc(Loc);
81  if (UserLoc.isInvalid())
82    return;
83
84  // Adjust the current include depth.
85  if (Reason == PPCallbacks::EnterFile) {
86    ++CurrentIncludeDepth;
87  } else if (Reason == PPCallbacks::ExitFile) {
88    if (CurrentIncludeDepth)
89      --CurrentIncludeDepth;
90
91    // We track when we are done with the predefines by watching for the first
92    // place where we drop back to a nesting depth of 1.
93    if (CurrentIncludeDepth == 1 && !HasProcessedPredefines)
94      HasProcessedPredefines = true;
95
96    return;
97  } else
98    return;
99
100  // Show the header if we are (a) past the predefines, or (b) showing all
101  // headers and in the predefines at a depth past the initial file and command
102  // line buffers.
103  bool ShowHeader = (HasProcessedPredefines ||
104                     (ShowAllHeaders && CurrentIncludeDepth > 2));
105
106  // Dump the header include information we are past the predefines buffer or
107  // are showing all headers.
108  if (ShowHeader && Reason == PPCallbacks::EnterFile) {
109    // Write to a temporary string to avoid unnecessary flushing on errs().
110    llvm::SmallString<512> Filename(UserLoc.getFilename());
111    Lexer::Stringify(Filename);
112
113    llvm::SmallString<256> Msg;
114    if (ShowDepth) {
115      // The main source file is at depth 1, so skip one dot.
116      for (unsigned i = 1; i != CurrentIncludeDepth; ++i)
117        Msg += '.';
118      Msg += ' ';
119    }
120    Msg += Filename;
121    Msg += '\n';
122
123    OutputFile->write(Msg.data(), Msg.size());
124  }
125}
126