DependencyFile.cpp revision c892c5fa92db137ff68d95afb13fe969d17f4fb2 
1//===--- DependencyFile.cpp - Generate dependency file --------------------===//
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// This code generates dependency files.
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/Frontend/Utils.h"
15#include "clang/Basic/FileManager.h"
16#include "clang/Basic/SourceManager.h"
17#include "clang/Frontend/DependencyOutputOptions.h"
18#include "clang/Frontend/FrontendDiagnostic.h"
19#include "clang/Lex/DirectoryLookup.h"
20#include "clang/Lex/LexDiagnostic.h"
21#include "clang/Lex/PPCallbacks.h"
22#include "clang/Lex/Preprocessor.h"
23#include "llvm/ADT/StringSet.h"
24#include "llvm/Support/Path.h"
25#include "llvm/Support/raw_ostream.h"
26
27using namespace clang;
28
29namespace {
30class DependencyFileCallback : public PPCallbacks {
31  std::vector<std::string> Files;
32  llvm::StringSet<> FilesSet;
33  const Preprocessor *PP;
34  std::vector<std::string> Targets;
35  raw_ostream *OS;
36  bool IncludeSystemHeaders;
37  bool PhonyTarget;
38  bool AddMissingHeaderDeps;
39private:
40  bool FileMatchesDepCriteria(const char *Filename,
41                              SrcMgr::CharacteristicKind FileType);
42  void AddFilename(StringRef Filename);
43  void OutputDependencyFile();
44
45public:
46  DependencyFileCallback(const Preprocessor *_PP,
47                         raw_ostream *_OS,
48                         const DependencyOutputOptions &Opts)
49    : PP(_PP), Targets(Opts.Targets), OS(_OS),
50      IncludeSystemHeaders(Opts.IncludeSystemHeaders),
51      PhonyTarget(Opts.UsePhonyTargets),
52      AddMissingHeaderDeps(Opts.AddMissingHeaderDeps) {}
53
54  virtual void FileChanged(SourceLocation Loc, FileChangeReason Reason,
55                           SrcMgr::CharacteristicKind FileType,
56                           FileID PrevFID);
57  virtual void InclusionDirective(SourceLocation HashLoc,
58                                  const Token &IncludeTok,
59                                  StringRef FileName,
60                                  bool IsAngled,
61                                  const FileEntry *File,
62                                  SourceLocation EndLoc,
63                                  StringRef SearchPath,
64                                  StringRef RelativePath);
65
66  virtual void EndOfMainFile() {
67    OutputDependencyFile();
68    delete OS;
69    OS = 0;
70  }
71};
72}
73
74void clang::AttachDependencyFileGen(Preprocessor &PP,
75                                    const DependencyOutputOptions &Opts) {
76  if (Opts.Targets.empty()) {
77    PP.getDiagnostics().Report(diag::err_fe_dependency_file_requires_MT);
78    return;
79  }
80
81  std::string Err;
82  raw_ostream *OS(new llvm::raw_fd_ostream(Opts.OutputFile.c_str(), Err));
83  if (!Err.empty()) {
84    PP.getDiagnostics().Report(diag::err_fe_error_opening)
85      << Opts.OutputFile << Err;
86    return;
87  }
88
89  // Disable the "file not found" diagnostic if the -MG option was given.
90  if (Opts.AddMissingHeaderDeps)
91    PP.SetSuppressIncludeNotFoundError(true);
92
93  PP.addPPCallbacks(new DependencyFileCallback(&PP, OS, Opts));
94}
95
96/// FileMatchesDepCriteria - Determine whether the given Filename should be
97/// considered as a dependency.
98bool DependencyFileCallback::FileMatchesDepCriteria(const char *Filename,
99                                          SrcMgr::CharacteristicKind FileType) {
100  if (strcmp("<built-in>", Filename) == 0)
101    return false;
102
103  if (IncludeSystemHeaders)
104    return true;
105
106  return FileType == SrcMgr::C_User;
107}
108
109void DependencyFileCallback::FileChanged(SourceLocation Loc,
110                                         FileChangeReason Reason,
111                                         SrcMgr::CharacteristicKind FileType,
112                                         FileID PrevFID) {
113  if (Reason != PPCallbacks::EnterFile)
114    return;
115
116  // Dependency generation really does want to go all the way to the
117  // file entry for a source location to find out what is depended on.
118  // We do not want #line markers to affect dependency generation!
119  SourceManager &SM = PP->getSourceManager();
120
121  const FileEntry *FE =
122    SM.getFileEntryForID(SM.getFileID(SM.getExpansionLoc(Loc)));
123  if (FE == 0) return;
124
125  StringRef Filename = FE->getName();
126  if (!FileMatchesDepCriteria(Filename.data(), FileType))
127    return;
128
129  // Remove leading "./" (or ".//" or "././" etc.)
130  while (Filename.size() > 2 && Filename[0] == '.' &&
131         llvm::sys::path::is_separator(Filename[1])) {
132    Filename = Filename.substr(1);
133    while (llvm::sys::path::is_separator(Filename[0]))
134      Filename = Filename.substr(1);
135  }
136
137  AddFilename(Filename);
138}
139
140void DependencyFileCallback::InclusionDirective(SourceLocation HashLoc,
141                                                const Token &IncludeTok,
142                                                StringRef FileName,
143                                                bool IsAngled,
144                                                const FileEntry *File,
145                                                SourceLocation EndLoc,
146                                                StringRef SearchPath,
147                                                StringRef RelativePath) {
148  if (AddMissingHeaderDeps && !File)
149    AddFilename(FileName);
150}
151
152void DependencyFileCallback::AddFilename(StringRef Filename) {
153  if (FilesSet.insert(Filename))
154    Files.push_back(Filename);
155}
156
157/// PrintFilename - GCC escapes spaces, but apparently not ' or " or other
158/// scary characters.
159static void PrintFilename(raw_ostream &OS, StringRef Filename) {
160  for (unsigned i = 0, e = Filename.size(); i != e; ++i) {
161    if (Filename[i] == ' ')
162      OS << '\\';
163    OS << Filename[i];
164  }
165}
166
167void DependencyFileCallback::OutputDependencyFile() {
168  // Write out the dependency targets, trying to avoid overly long
169  // lines when possible. We try our best to emit exactly the same
170  // dependency file as GCC (4.2), assuming the included files are the
171  // same.
172  const unsigned MaxColumns = 75;
173  unsigned Columns = 0;
174
175  for (std::vector<std::string>::iterator
176         I = Targets.begin(), E = Targets.end(); I != E; ++I) {
177    unsigned N = I->length();
178    if (Columns == 0) {
179      Columns += N;
180    } else if (Columns + N + 2 > MaxColumns) {
181      Columns = N + 2;
182      *OS << " \\\n  ";
183    } else {
184      Columns += N + 1;
185      *OS << ' ';
186    }
187    // Targets already quoted as needed.
188    *OS << *I;
189  }
190
191  *OS << ':';
192  Columns += 1;
193
194  // Now add each dependency in the order it was seen, but avoiding
195  // duplicates.
196  for (std::vector<std::string>::iterator I = Files.begin(),
197         E = Files.end(); I != E; ++I) {
198    // Start a new line if this would exceed the column limit. Make
199    // sure to leave space for a trailing " \" in case we need to
200    // break the line on the next iteration.
201    unsigned N = I->length();
202    if (Columns + (N + 1) + 2 > MaxColumns) {
203      *OS << " \\\n ";
204      Columns = 2;
205    }
206    *OS << ' ';
207    PrintFilename(*OS, *I);
208    Columns += N + 1;
209  }
210  *OS << '\n';
211
212  // Create phony targets if requested.
213  if (PhonyTarget && !Files.empty()) {
214    // Skip the first entry, this is always the input file itself.
215    for (std::vector<std::string>::iterator I = Files.begin() + 1,
216           E = Files.end(); I != E; ++I) {
217      *OS << '\n';
218      PrintFilename(*OS, *I);
219      *OS << ":\n";
220    }
221  }
222}
223
224