DependencyFile.cpp revision a5d10c4df435964600e104ebef6a96b106e416b7 
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  ~DependencyFileCallback() {
52    OutputDependencyFile();
53    OS->flush();
54    delete OS;
55  }
56
57  virtual void FileChanged(SourceLocation Loc, FileChangeReason Reason,
58                           SrcMgr::CharacteristicKind FileType);
59};
60}
61
62void clang::AttachDependencyFileGen(Preprocessor &PP,
63                                    const DependencyOutputOptions &Opts) {
64  if (Opts.Targets.empty()) {
65    PP.getDiagnostics().Report(diag::err_fe_dependency_file_requires_MT);
66    return;
67  }
68
69  std::string Err;
70  llvm::raw_ostream *OS(new llvm::raw_fd_ostream(Opts.OutputFile.c_str(), Err));
71  if (!Err.empty()) {
72    PP.getDiagnostics().Report(diag::err_fe_error_opening)
73      << Opts.OutputFile << Err;
74    return;
75  }
76
77  PP.addPPCallbacks(new DependencyFileCallback(&PP, OS, Opts));
78}
79
80/// FileMatchesDepCriteria - Determine whether the given Filename should be
81/// considered as a dependency.
82bool DependencyFileCallback::FileMatchesDepCriteria(const char *Filename,
83                                          SrcMgr::CharacteristicKind FileType) {
84  if (strcmp("<built-in>", Filename) == 0)
85    return false;
86
87  if (IncludeSystemHeaders)
88    return true;
89
90  return FileType == SrcMgr::C_User;
91}
92
93void DependencyFileCallback::FileChanged(SourceLocation Loc,
94                                         FileChangeReason Reason,
95                                         SrcMgr::CharacteristicKind FileType) {
96  if (Reason != PPCallbacks::EnterFile)
97    return;
98
99  // Dependency generation really does want to go all the way to the
100  // file entry for a source location to find out what is depended on.
101  // We do not want #line markers to affect dependency generation!
102  SourceManager &SM = PP->getSourceManager();
103
104  const FileEntry *FE =
105    SM.getFileEntryForID(SM.getFileID(SM.getInstantiationLoc(Loc)));
106  if (FE == 0) return;
107
108  const char *Filename = FE->getName();
109  if (!FileMatchesDepCriteria(Filename, FileType))
110    return;
111
112  // Remove leading "./"
113  if (Filename[0] == '.' && Filename[1] == '/')
114    Filename = &Filename[2];
115
116  if (FilesSet.insert(Filename))
117    Files.push_back(Filename);
118}
119
120void DependencyFileCallback::OutputDependencyFile() {
121  // Write out the dependency targets, trying to avoid overly long
122  // lines when possible. We try our best to emit exactly the same
123  // dependency file as GCC (4.2), assuming the included files are the
124  // same.
125  const unsigned MaxColumns = 75;
126  unsigned Columns = 0;
127
128  for (std::vector<std::string>::iterator
129         I = Targets.begin(), E = Targets.end(); I != E; ++I) {
130    unsigned N = I->length();
131    if (Columns == 0) {
132      Columns += N;
133      *OS << *I;
134    } else if (Columns + N + 2 > MaxColumns) {
135      Columns = N + 2;
136      *OS << " \\\n  " << *I;
137    } else {
138      Columns += N + 1;
139      *OS << ' ' << *I;
140    }
141  }
142
143  *OS << ':';
144  Columns += 1;
145
146  // Now add each dependency in the order it was seen, but avoiding
147  // duplicates.
148  for (std::vector<std::string>::iterator I = Files.begin(),
149         E = Files.end(); I != E; ++I) {
150    // Start a new line if this would exceed the column limit. Make
151    // sure to leave space for a trailing " \" in case we need to
152    // break the line on the next iteration.
153    unsigned N = I->length();
154    if (Columns + (N + 1) + 2 > MaxColumns) {
155      *OS << " \\\n ";
156      Columns = 2;
157    }
158    *OS << ' ' << *I;
159    Columns += N + 1;
160  }
161  *OS << '\n';
162
163  // Create phony targets if requested.
164  if (PhonyTarget) {
165    // Skip the first entry, this is always the input file itself.
166    for (std::vector<std::string>::iterator I = Files.begin() + 1,
167           E = Files.end(); I != E; ++I) {
168      *OS << '\n';
169      *OS << *I << ":\n";
170    }
171  }
172}
173
174