DependencyFile.cpp revision dbd8209b33e6c9f151e4913a9c095d64a95439c4 
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/SourceLocation.h"
17#include "clang/Basic/SourceManager.h"
18#include "clang/Frontend/DependencyOutputOptions.h"
19#include "clang/Frontend/FrontendDiagnostic.h"
20#include "clang/Lex/DirectoryLookup.h"
21#include "clang/Lex/PPCallbacks.h"
22#include "clang/Lex/Preprocessor.h"
23#include "llvm/ADT/StringSet.h"
24#include "llvm/Support/raw_ostream.h"
25#include <string>
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;
38private:
39  bool FileMatchesDepCriteria(const char *Filename,
40                              SrcMgr::CharacteristicKind FileType);
41  void OutputDependencyFile();
42
43public:
44  DependencyFileCallback(const Preprocessor *_PP,
45                         llvm::raw_ostream *_OS,
46                         const DependencyOutputOptions &Opts)
47    : PP(_PP), Targets(Opts.Targets), OS(_OS),
48      IncludeSystemHeaders(Opts.IncludeSystemHeaders),
49      PhonyTarget(Opts.UsePhonyTargets) {}
50
51  virtual void FileChanged(SourceLocation Loc, FileChangeReason Reason,
52                           SrcMgr::CharacteristicKind FileType);
53
54  virtual void EndOfMainFile() {
55    OutputDependencyFile();
56    OS->flush();
57    delete OS;
58    OS = 0;
59  }
60};
61}
62
63void clang::AttachDependencyFileGen(Preprocessor &PP,
64                                    const DependencyOutputOptions &Opts) {
65  if (Opts.Targets.empty()) {
66    PP.getDiagnostics().Report(diag::err_fe_dependency_file_requires_MT);
67    return;
68  }
69
70  std::string Err;
71  llvm::raw_ostream *OS(new llvm::raw_fd_ostream(Opts.OutputFile.c_str(), Err));
72  if (!Err.empty()) {
73    PP.getDiagnostics().Report(diag::err_fe_error_opening)
74      << Opts.OutputFile << Err;
75    return;
76  }
77
78  PP.addPPCallbacks(new DependencyFileCallback(&PP, OS, Opts));
79}
80
81/// FileMatchesDepCriteria - Determine whether the given Filename should be
82/// considered as a dependency.
83bool DependencyFileCallback::FileMatchesDepCriteria(const char *Filename,
84                                          SrcMgr::CharacteristicKind FileType) {
85  if (strcmp("<built-in>", Filename) == 0)
86    return false;
87
88  if (IncludeSystemHeaders)
89    return true;
90
91  return FileType == SrcMgr::C_User;
92}
93
94void DependencyFileCallback::FileChanged(SourceLocation Loc,
95                                         FileChangeReason Reason,
96                                         SrcMgr::CharacteristicKind FileType) {
97  if (Reason != PPCallbacks::EnterFile)
98    return;
99
100  // Dependency generation really does want to go all the way to the
101  // file entry for a source location to find out what is depended on.
102  // We do not want #line markers to affect dependency generation!
103  SourceManager &SM = PP->getSourceManager();
104
105  const FileEntry *FE =
106    SM.getFileEntryForID(SM.getFileID(SM.getInstantiationLoc(Loc)));
107  if (FE == 0) return;
108
109  const char *Filename = FE->getName();
110  if (!FileMatchesDepCriteria(Filename, FileType))
111    return;
112
113  // Remove leading "./"
114  if (Filename[0] == '.' && Filename[1] == '/')
115    Filename = &Filename[2];
116
117  if (FilesSet.insert(Filename))
118    Files.push_back(Filename);
119}
120
121void DependencyFileCallback::OutputDependencyFile() {
122  // Write out the dependency targets, trying to avoid overly long
123  // lines when possible. We try our best to emit exactly the same
124  // dependency file as GCC (4.2), assuming the included files are the
125  // same.
126  const unsigned MaxColumns = 75;
127  unsigned Columns = 0;
128
129  for (std::vector<std::string>::iterator
130         I = Targets.begin(), E = Targets.end(); I != E; ++I) {
131    unsigned N = I->length();
132    if (Columns == 0) {
133      Columns += N;
134      *OS << *I;
135    } else if (Columns + N + 2 > MaxColumns) {
136      Columns = N + 2;
137      *OS << " \\\n  " << *I;
138    } else {
139      Columns += N + 1;
140      *OS << ' ' << *I;
141    }
142  }
143
144  *OS << ':';
145  Columns += 1;
146
147  // Now add each dependency in the order it was seen, but avoiding
148  // duplicates.
149  for (std::vector<std::string>::iterator I = Files.begin(),
150         E = Files.end(); I != E; ++I) {
151    // Start a new line if this would exceed the column limit. Make
152    // sure to leave space for a trailing " \" in case we need to
153    // break the line on the next iteration.
154    unsigned N = I->length();
155    if (Columns + (N + 1) + 2 > MaxColumns) {
156      *OS << " \\\n ";
157      Columns = 2;
158    }
159    *OS << ' ' << *I;
160    Columns += N + 1;
161  }
162  *OS << '\n';
163
164  // Create phony targets if requested.
165  if (PhonyTarget) {
166    // Skip the first entry, this is always the input file itself.
167    for (std::vector<std::string>::iterator I = Files.begin() + 1,
168           E = Files.end(); I != E; ++I) {
169      *OS << '\n';
170      *OS << *I << ":\n";
171    }
172  }
173}
174
175