DependencyFile.cpp revision bb52786da8d055568eef6e5694288c1258bc8c2a 
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  llvm::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(llvm::StringRef Filename);
43  void OutputDependencyFile();
44
45public:
46  DependencyFileCallback(const Preprocessor *_PP,
47                         llvm::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  virtual void InclusionDirective(SourceLocation HashLoc,
57                                  const Token &IncludeTok,
58                                  llvm::StringRef FileName,
59                                  bool IsAngled,
60                                  const FileEntry *File,
61                                  SourceLocation EndLoc,
62                                  llvm::StringRef SearchPath,
63                                  llvm::StringRef RelativePath);
64
65  virtual void EndOfMainFile() {
66    OutputDependencyFile();
67    delete OS;
68    OS = 0;
69  }
70};
71}
72
73void clang::AttachDependencyFileGen(Preprocessor &PP,
74                                    const DependencyOutputOptions &Opts) {
75  if (Opts.Targets.empty()) {
76    PP.getDiagnostics().Report(diag::err_fe_dependency_file_requires_MT);
77    return;
78  }
79
80  std::string Err;
81  llvm::raw_ostream *OS(new llvm::raw_fd_ostream(Opts.OutputFile.c_str(), Err));
82  if (!Err.empty()) {
83    PP.getDiagnostics().Report(diag::err_fe_error_opening)
84      << Opts.OutputFile << Err;
85    return;
86  }
87
88  // Disable the "file not found" diagnostic if the -MG option was given.
89  // FIXME: Ideally this would live in the driver, but we don't have the ability
90  // to remap individual diagnostics there without creating a DiagGroup, in
91  // which case we would need to prevent the group name from showing up in
92  // diagnostics.
93  if (Opts.AddMissingHeaderDeps) {
94    PP.getDiagnostics().setDiagnosticMapping(diag::warn_pp_file_not_found,
95                                            diag::MAP_IGNORE, SourceLocation());
96  }
97
98  PP.addPPCallbacks(new DependencyFileCallback(&PP, OS, Opts));
99}
100
101/// FileMatchesDepCriteria - Determine whether the given Filename should be
102/// considered as a dependency.
103bool DependencyFileCallback::FileMatchesDepCriteria(const char *Filename,
104                                          SrcMgr::CharacteristicKind FileType) {
105  if (strcmp("<built-in>", Filename) == 0)
106    return false;
107
108  if (IncludeSystemHeaders)
109    return true;
110
111  return FileType == SrcMgr::C_User;
112}
113
114void DependencyFileCallback::FileChanged(SourceLocation Loc,
115                                         FileChangeReason Reason,
116                                         SrcMgr::CharacteristicKind FileType) {
117  if (Reason != PPCallbacks::EnterFile)
118    return;
119
120  // Dependency generation really does want to go all the way to the
121  // file entry for a source location to find out what is depended on.
122  // We do not want #line markers to affect dependency generation!
123  SourceManager &SM = PP->getSourceManager();
124
125  const FileEntry *FE =
126    SM.getFileEntryForID(SM.getFileID(SM.getInstantiationLoc(Loc)));
127  if (FE == 0) return;
128
129  llvm::StringRef Filename = FE->getName();
130  if (!FileMatchesDepCriteria(Filename.data(), FileType))
131    return;
132
133  // Remove leading "./" (or ".//" or "././" etc.)
134  while (Filename.size() > 2 && Filename[0] == '.' &&
135         llvm::sys::path::is_separator(Filename[1])) {
136    Filename = Filename.substr(1);
137    while (llvm::sys::path::is_separator(Filename[0]))
138      Filename = Filename.substr(1);
139  }
140
141  AddFilename(Filename);
142}
143
144void DependencyFileCallback::InclusionDirective(SourceLocation HashLoc,
145                                                const Token &IncludeTok,
146                                                llvm::StringRef FileName,
147                                                bool IsAngled,
148                                                const FileEntry *File,
149                                                SourceLocation EndLoc,
150                                                llvm::StringRef SearchPath,
151                                                llvm::StringRef RelativePath) {
152  if (AddMissingHeaderDeps && !File)
153    AddFilename(FileName);
154}
155
156void DependencyFileCallback::AddFilename(llvm::StringRef Filename) {
157  if (FilesSet.insert(Filename))
158    Files.push_back(Filename);
159}
160
161/// PrintFilename - GCC escapes spaces, but apparently not ' or " or other
162/// scary characters.
163static void PrintFilename(llvm::raw_ostream &OS, llvm::StringRef Filename) {
164  for (unsigned i = 0, e = Filename.size(); i != e; ++i) {
165    if (Filename[i] == ' ')
166      OS << '\\';
167    OS << Filename[i];
168  }
169}
170
171void DependencyFileCallback::OutputDependencyFile() {
172  // Write out the dependency targets, trying to avoid overly long
173  // lines when possible. We try our best to emit exactly the same
174  // dependency file as GCC (4.2), assuming the included files are the
175  // same.
176  const unsigned MaxColumns = 75;
177  unsigned Columns = 0;
178
179  for (std::vector<std::string>::iterator
180         I = Targets.begin(), E = Targets.end(); I != E; ++I) {
181    unsigned N = I->length();
182    if (Columns == 0) {
183      Columns += N;
184    } else if (Columns + N + 2 > MaxColumns) {
185      Columns = N + 2;
186      *OS << " \\\n  ";
187    } else {
188      Columns += N + 1;
189      *OS << ' ';
190    }
191    // Targets already quoted as needed.
192    *OS << *I;
193  }
194
195  *OS << ':';
196  Columns += 1;
197
198  // Now add each dependency in the order it was seen, but avoiding
199  // duplicates.
200  for (std::vector<std::string>::iterator I = Files.begin(),
201         E = Files.end(); I != E; ++I) {
202    // Start a new line if this would exceed the column limit. Make
203    // sure to leave space for a trailing " \" in case we need to
204    // break the line on the next iteration.
205    unsigned N = I->length();
206    if (Columns + (N + 1) + 2 > MaxColumns) {
207      *OS << " \\\n ";
208      Columns = 2;
209    }
210    *OS << ' ';
211    PrintFilename(*OS, *I);
212    Columns += N + 1;
213  }
214  *OS << '\n';
215
216  // Create phony targets if requested.
217  if (PhonyTarget && !Files.empty()) {
218    // Skip the first entry, this is always the input file itself.
219    for (std::vector<std::string>::iterator I = Files.begin() + 1,
220           E = Files.end(); I != E; ++I) {
221      *OS << '\n';
222      PrintFilename(*OS, *I);
223      *OS << ":\n";
224    }
225  }
226}
227
228