DependencyFile.cpp revision b09f6e15c59b89d5820db8ef40598eb1d1323c1f 
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/SourceManager.h"
16#include "clang/Basic/FileManager.h"
17#include "clang/Lex/Preprocessor.h"
18#include "clang/Lex/PPCallbacks.h"
19#include "clang/Lex/DirectoryLookup.h"
20#include "clang/Basic/SourceLocation.h"
21#include "llvm/ADT/StringSet.h"
22#include "llvm/System/Path.h"
23#include "llvm/Support/CommandLine.h"
24#include "llvm/Support/Compiler.h"
25#include "llvm/Support/raw_ostream.h"
26#include <string>
27
28using namespace clang;
29
30namespace {
31class VISIBILITY_HIDDEN DependencyFileCallback : public PPCallbacks {
32  std::vector<std::string> Files;
33  llvm::StringSet<> FilesSet;
34  const Preprocessor *PP;
35  std::vector<std::string> Targets;
36  llvm::raw_ostream *OS;
37  bool IncludeSystemHeaders;
38  bool PhonyTarget;
39private:
40  bool FileMatchesDepCriteria(const char *Filename,
41                              SrcMgr::CharacteristicKind FileType);
42  void OutputDependencyFile();
43
44public:
45  DependencyFileCallback(const Preprocessor *_PP,
46                         llvm::raw_ostream *_OS,
47                         const std::vector<std::string> &_Targets,
48                         bool _IncludeSystemHeaders,
49                         bool _PhonyTarget)
50    : PP(_PP), Targets(_Targets), OS(_OS),
51      IncludeSystemHeaders(_IncludeSystemHeaders), PhonyTarget(_PhonyTarget) {}
52
53  ~DependencyFileCallback() {
54    OutputDependencyFile();
55    OS->flush();
56    delete OS;
57  }
58
59  virtual void FileChanged(SourceLocation Loc, FileChangeReason Reason,
60                           SrcMgr::CharacteristicKind FileType);
61};
62}
63
64
65
66void clang::AttachDependencyFileGen(Preprocessor *PP, llvm::raw_ostream *OS,
67                                    std::vector<std::string> &Targets,
68                                    bool IncludeSystemHeaders,
69                                    bool PhonyTarget) {
70  assert(!Targets.empty() && "Target required for dependency generation");
71
72  DependencyFileCallback *PPDep =
73    new DependencyFileCallback(PP, OS, Targets, IncludeSystemHeaders,
74                               PhonyTarget);
75  PP->setPPCallbacks(PPDep);
76}
77
78/// FileMatchesDepCriteria - Determine whether the given Filename should be
79/// considered as a dependency.
80bool DependencyFileCallback::FileMatchesDepCriteria(const char *Filename,
81                                          SrcMgr::CharacteristicKind FileType) {
82  if (strcmp("<built-in>", Filename) == 0)
83    return false;
84
85  if (IncludeSystemHeaders)
86    return true;
87
88  return FileType == SrcMgr::C_User;
89}
90
91void DependencyFileCallback::FileChanged(SourceLocation Loc,
92                                         FileChangeReason Reason,
93                                         SrcMgr::CharacteristicKind FileType) {
94  if (Reason != PPCallbacks::EnterFile)
95    return;
96
97  // Dependency generation really does want to go all the way to the
98  // file entry for a source location to find out what is depended on.
99  // We do not want #line markers to affect dependency generation!
100  SourceManager &SM = PP->getSourceManager();
101
102  const FileEntry *FE =
103    SM.getFileEntryForID(SM.getFileID(SM.getInstantiationLoc(Loc)));
104  if (FE == 0) return;
105
106  const char *Filename = FE->getName();
107  if (!FileMatchesDepCriteria(Filename, FileType))
108    return;
109
110  // Remove leading "./"
111  if (Filename[0] == '.' && Filename[1] == '/')
112    Filename = &Filename[2];
113
114  if (FilesSet.insert(Filename))
115    Files.push_back(Filename);
116}
117
118void DependencyFileCallback::OutputDependencyFile() {
119  // Write out the dependency targets, trying to avoid overly long
120  // lines when possible. We try our best to emit exactly the same
121  // dependency file as GCC (4.2), assuming the included files are the
122  // same.
123  const unsigned MaxColumns = 75;
124  unsigned Columns = 0;
125
126  for (std::vector<std::string>::iterator
127         I = Targets.begin(), E = Targets.end(); I != E; ++I) {
128    unsigned N = I->length();
129    if (Columns == 0) {
130      Columns += N;
131      *OS << *I;
132    } else if (Columns + N + 2 > MaxColumns) {
133      Columns = N + 2;
134      *OS << " \\\n  " << *I;
135    } else {
136      Columns += N + 1;
137      *OS << ' ' << *I;
138    }
139  }
140
141  *OS << ':';
142  Columns += 1;
143
144  // Now add each dependency in the order it was seen, but avoiding
145  // duplicates.
146  for (std::vector<std::string>::iterator I = Files.begin(),
147         E = Files.end(); I != E; ++I) {
148    // Start a new line if this would exceed the column limit. Make
149    // sure to leave space for a trailing " \" in case we need to
150    // break the line on the next iteration.
151    unsigned N = I->length();
152    if (Columns + (N + 1) + 2 > MaxColumns) {
153      *OS << " \\\n ";
154      Columns = 2;
155    }
156    *OS << ' ' << *I;
157    Columns += N + 1;
158  }
159  *OS << '\n';
160
161  // Create phony targets if requested.
162  if (PhonyTarget) {
163    // Skip the first entry, this is always the input file itself.
164    for (std::vector<std::string>::iterator I = Files.begin() + 1,
165           E = Files.end(); I != E; ++I) {
166      *OS << '\n';
167      *OS << *I << ":\n";
168    }
169  }
170}
171
172