lib/Frontend/DependencyFile.cpp

   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/PPCallbacks.h"
  21 #include "clang/Lex/Preprocessor.h"
  22 #include "llvm/ADT/StringSet.h"
  23 #include "llvm/Support/raw_ostream.h"
  24
  25 using namespace clang;
  26
  27 namespace {
  28 class DependencyFileCallback : public PPCallbacks {
  29   std::vector<std::string> Files;
  30   llvm::StringSet<> FilesSet;
  31   const Preprocessor *PP;
  32   std::vector<std::string> Targets;
  33   llvm::raw_ostream *OS;
  34   bool IncludeSystemHeaders;
  35   bool PhonyTarget;
  36 private:
  37   bool FileMatchesDepCriteria(const char *Filename,
  38                               SrcMgr::CharacteristicKind FileType);
  39   void OutputDependencyFile();
  40
  41 public:
  42   DependencyFileCallback(const Preprocessor *_PP,
  43                          llvm::raw_ostream *_OS,
  44                          const DependencyOutputOptions &Opts)
  45     : PP(_PP), Targets(Opts.Targets), OS(_OS),
  46       IncludeSystemHeaders(Opts.IncludeSystemHeaders),
  47       PhonyTarget(Opts.UsePhonyTargets) {}
  48
  49   virtual void FileChanged(SourceLocation Loc, FileChangeReason Reason,
  50                            SrcMgr::CharacteristicKind FileType);
  51
  52   virtual void EndOfMainFile() {
  53     OutputDependencyFile();
  54     delete OS;
  55     OS = 0;
  56   }
  57 };
  58 }
  59
  60 void clang::AttachDependencyFileGen(Preprocessor &PP,
  61                                     const DependencyOutputOptions &Opts) {
  62   if (Opts.Targets.empty()) {
  63     PP.getDiagnostics().Report(diag::err_fe_dependency_file_requires_MT);
  64     return;
  65   }
  66
  67   std::string Err;
  68   llvm::raw_ostream *OS(new llvm::raw_fd_ostream(Opts.OutputFile.c_str(), Err));
  69   if (!Err.empty()) {
  70     PP.getDiagnostics().Report(diag::err_fe_error_opening)
  71       << Opts.OutputFile << Err;
  72     return;
  73   }
  74
  75   PP.addPPCallbacks(new DependencyFileCallback(&PP, OS, Opts));
  76 }
  77
  78 /// FileMatchesDepCriteria - Determine whether the given Filename should be
  79 /// considered as a dependency.
  80 bool 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
  91 void 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
 118 /// PrintFilename - GCC escapes spaces, but apparently not ' or " or other
 119 /// scary characters.
 120 static void PrintFilename(llvm::raw_ostream &OS, llvm::StringRef Filename) {
 121   for (unsigned i = 0, e = Filename.size(); i != e; ++i) {
 122     if (Filename[i] == ' ')
 123       OS << '\\';
 124     OS << Filename[i];
 125   }
 126 }
 127
 128 void DependencyFileCallback::OutputDependencyFile() {
 129   // Write out the dependency targets, trying to avoid overly long
 130   // lines when possible. We try our best to emit exactly the same
 131   // dependency file as GCC (4.2), assuming the included files are the
 132   // same.
 133   const unsigned MaxColumns = 75;
 134   unsigned Columns = 0;
 135
 136   for (std::vector<std::string>::iterator
 137          I = Targets.begin(), E = Targets.end(); I != E; ++I) {
 138     unsigned N = I->length();
 139     if (Columns == 0) {
 140       Columns += N;
 141     } else if (Columns + N + 2 > MaxColumns) {
 142       Columns = N + 2;
 143       *OS << " \\\n  ";
 144     } else {
 145       Columns += N + 1;
 146       *OS << ' ';
 147     }
 148     // Targets already quoted as needed.
 149     *OS << *I;
 150   }
 151
 152   *OS << ':';
 153   Columns += 1;
 154
 155   // Now add each dependency in the order it was seen, but avoiding
 156   // duplicates.
 157   for (std::vector<std::string>::iterator I = Files.begin(),
 158          E = Files.end(); I != E; ++I) {
 159     // Start a new line if this would exceed the column limit. Make
 160     // sure to leave space for a trailing " \" in case we need to
 161     // break the line on the next iteration.
 162     unsigned N = I->length();
 163     if (Columns + (N + 1) + 2 > MaxColumns) {
 164       *OS << " \\\n ";
 165       Columns = 2;
 166     }
 167     *OS << ' ';
 168     PrintFilename(*OS, *I);
 169     Columns += N + 1;
 170   }
 171   *OS << '\n';
 172
 173   // Create phony targets if requested.
 174   if (PhonyTarget) {
 175     // Skip the first entry, this is always the input file itself.
 176     for (std::vector<std::string>::iterator I = Files.begin() + 1,
 177            E = Files.end(); I != E; ++I) {
 178       *OS << '\n';
 179       PrintFilename(*OS, *I);
 180       *OS << ":\n";
 181     }
 182   }
 183 }
 184