1 //===--- DependencyFile.cpp - Generate dependency file --------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This code generates dependency files. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "clang/Frontend/Utils.h" 14 #include "clang/Basic/FileManager.h" 15 #include "clang/Basic/SourceManager.h" 16 #include "clang/Frontend/DependencyOutputOptions.h" 17 #include "clang/Frontend/FrontendDiagnostic.h" 18 #include "clang/Lex/DirectoryLookup.h" 19 #include "clang/Lex/ModuleMap.h" 20 #include "clang/Lex/PPCallbacks.h" 21 #include "clang/Lex/Preprocessor.h" 22 #include "clang/Serialization/ASTReader.h" 23 #include "llvm/ADT/StringSet.h" 24 #include "llvm/ADT/StringSwitch.h" 25 #include "llvm/Support/FileSystem.h" 26 #include "llvm/Support/Path.h" 27 #include "llvm/Support/raw_ostream.h" 28 29 using namespace clang; 30 31 namespace { 32 struct DepCollectorPPCallbacks : public PPCallbacks { 33 DependencyCollector &DepCollector; 34 Preprocessor &PP; 35 DepCollectorPPCallbacks(DependencyCollector &L, Preprocessor &PP) 36 : DepCollector(L), PP(PP) {} 37 38 void LexedFileChanged(FileID FID, LexedFileChangeReason Reason, 39 SrcMgr::CharacteristicKind FileType, FileID PrevFID, 40 SourceLocation Loc) override { 41 if (Reason != PPCallbacks::LexedFileChangeReason::EnterFile) 42 return; 43 44 // Dependency generation really does want to go all the way to the 45 // file entry for a source location to find out what is depended on. 46 // We do not want #line markers to affect dependency generation! 47 if (Optional<StringRef> Filename = 48 PP.getSourceManager().getNonBuiltinFilenameForID(FID)) 49 DepCollector.maybeAddDependency( 50 llvm::sys::path::remove_leading_dotslash(*Filename), 51 /*FromModule*/ false, isSystem(FileType), /*IsModuleFile*/ false, 52 /*IsMissing*/ false); 53 } 54 55 void FileSkipped(const FileEntryRef &SkippedFile, const Token &FilenameTok, 56 SrcMgr::CharacteristicKind FileType) override { 57 StringRef Filename = 58 llvm::sys::path::remove_leading_dotslash(SkippedFile.getName()); 59 DepCollector.maybeAddDependency(Filename, /*FromModule=*/false, 60 /*IsSystem=*/isSystem(FileType), 61 /*IsModuleFile=*/false, 62 /*IsMissing=*/false); 63 } 64 65 void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok, 66 StringRef FileName, bool IsAngled, 67 CharSourceRange FilenameRange, 68 Optional<FileEntryRef> File, StringRef SearchPath, 69 StringRef RelativePath, const Module *Imported, 70 SrcMgr::CharacteristicKind FileType) override { 71 if (!File) 72 DepCollector.maybeAddDependency(FileName, /*FromModule*/false, 73 /*IsSystem*/false, /*IsModuleFile*/false, 74 /*IsMissing*/true); 75 // Files that actually exist are handled by FileChanged. 76 } 77 78 void HasInclude(SourceLocation Loc, StringRef SpelledFilename, bool IsAngled, 79 Optional<FileEntryRef> File, 80 SrcMgr::CharacteristicKind FileType) override { 81 if (!File) 82 return; 83 StringRef Filename = 84 llvm::sys::path::remove_leading_dotslash(File->getName()); 85 DepCollector.maybeAddDependency(Filename, /*FromModule=*/false, 86 /*IsSystem=*/isSystem(FileType), 87 /*IsModuleFile=*/false, 88 /*IsMissing=*/false); 89 } 90 91 void EndOfMainFile() override { 92 DepCollector.finishedMainFile(PP.getDiagnostics()); 93 } 94 }; 95 96 struct DepCollectorMMCallbacks : public ModuleMapCallbacks { 97 DependencyCollector &DepCollector; 98 DepCollectorMMCallbacks(DependencyCollector &DC) : DepCollector(DC) {} 99 100 void moduleMapFileRead(SourceLocation Loc, const FileEntry &Entry, 101 bool IsSystem) override { 102 StringRef Filename = Entry.getName(); 103 DepCollector.maybeAddDependency(Filename, /*FromModule*/false, 104 /*IsSystem*/IsSystem, 105 /*IsModuleFile*/false, 106 /*IsMissing*/false); 107 } 108 }; 109 110 struct DepCollectorASTListener : public ASTReaderListener { 111 DependencyCollector &DepCollector; 112 DepCollectorASTListener(DependencyCollector &L) : DepCollector(L) { } 113 bool needsInputFileVisitation() override { return true; } 114 bool needsSystemInputFileVisitation() override { 115 return DepCollector.needSystemDependencies(); 116 } 117 void visitModuleFile(StringRef Filename, 118 serialization::ModuleKind Kind) override { 119 DepCollector.maybeAddDependency(Filename, /*FromModule*/true, 120 /*IsSystem*/false, /*IsModuleFile*/true, 121 /*IsMissing*/false); 122 } 123 bool visitInputFile(StringRef Filename, bool IsSystem, 124 bool IsOverridden, bool IsExplicitModule) override { 125 if (IsOverridden || IsExplicitModule) 126 return true; 127 128 DepCollector.maybeAddDependency(Filename, /*FromModule*/true, IsSystem, 129 /*IsModuleFile*/false, /*IsMissing*/false); 130 return true; 131 } 132 }; 133 } // end anonymous namespace 134 135 void DependencyCollector::maybeAddDependency(StringRef Filename, 136 bool FromModule, bool IsSystem, 137 bool IsModuleFile, 138 bool IsMissing) { 139 if (sawDependency(Filename, FromModule, IsSystem, IsModuleFile, IsMissing)) 140 addDependency(Filename); 141 } 142 143 bool DependencyCollector::addDependency(StringRef Filename) { 144 StringRef SearchPath; 145 #ifdef _WIN32 146 // Make the search insensitive to case and separators. 147 llvm::SmallString<256> TmpPath = Filename; 148 llvm::sys::path::native(TmpPath); 149 std::transform(TmpPath.begin(), TmpPath.end(), TmpPath.begin(), ::tolower); 150 SearchPath = TmpPath.str(); 151 #else 152 SearchPath = Filename; 153 #endif 154 155 if (Seen.insert(SearchPath).second) { 156 Dependencies.push_back(std::string(Filename)); 157 return true; 158 } 159 return false; 160 } 161 162 static bool isSpecialFilename(StringRef Filename) { 163 return llvm::StringSwitch<bool>(Filename) 164 .Case("<built-in>", true) 165 .Case("<stdin>", true) 166 .Default(false); 167 } 168 169 bool DependencyCollector::sawDependency(StringRef Filename, bool FromModule, 170 bool IsSystem, bool IsModuleFile, 171 bool IsMissing) { 172 return !isSpecialFilename(Filename) && 173 (needSystemDependencies() || !IsSystem); 174 } 175 176 DependencyCollector::~DependencyCollector() { } 177 void DependencyCollector::attachToPreprocessor(Preprocessor &PP) { 178 PP.addPPCallbacks(std::make_unique<DepCollectorPPCallbacks>(*this, PP)); 179 PP.getHeaderSearchInfo().getModuleMap().addModuleMapCallbacks( 180 std::make_unique<DepCollectorMMCallbacks>(*this)); 181 } 182 void DependencyCollector::attachToASTReader(ASTReader &R) { 183 R.addListener(std::make_unique<DepCollectorASTListener>(*this)); 184 } 185 186 DependencyFileGenerator::DependencyFileGenerator( 187 const DependencyOutputOptions &Opts) 188 : OutputFile(Opts.OutputFile), Targets(Opts.Targets), 189 IncludeSystemHeaders(Opts.IncludeSystemHeaders), 190 PhonyTarget(Opts.UsePhonyTargets), 191 AddMissingHeaderDeps(Opts.AddMissingHeaderDeps), SeenMissingHeader(false), 192 IncludeModuleFiles(Opts.IncludeModuleFiles), 193 OutputFormat(Opts.OutputFormat), InputFileIndex(0) { 194 for (const auto &ExtraDep : Opts.ExtraDeps) { 195 if (addDependency(ExtraDep.first)) 196 ++InputFileIndex; 197 } 198 } 199 200 void DependencyFileGenerator::attachToPreprocessor(Preprocessor &PP) { 201 // Disable the "file not found" diagnostic if the -MG option was given. 202 if (AddMissingHeaderDeps) 203 PP.SetSuppressIncludeNotFoundError(true); 204 205 DependencyCollector::attachToPreprocessor(PP); 206 } 207 208 bool DependencyFileGenerator::sawDependency(StringRef Filename, bool FromModule, 209 bool IsSystem, bool IsModuleFile, 210 bool IsMissing) { 211 if (IsMissing) { 212 // Handle the case of missing file from an inclusion directive. 213 if (AddMissingHeaderDeps) 214 return true; 215 SeenMissingHeader = true; 216 return false; 217 } 218 if (IsModuleFile && !IncludeModuleFiles) 219 return false; 220 221 if (isSpecialFilename(Filename)) 222 return false; 223 224 if (IncludeSystemHeaders) 225 return true; 226 227 return !IsSystem; 228 } 229 230 void DependencyFileGenerator::finishedMainFile(DiagnosticsEngine &Diags) { 231 outputDependencyFile(Diags); 232 } 233 234 /// Print the filename, with escaping or quoting that accommodates the three 235 /// most likely tools that use dependency files: GNU Make, BSD Make, and 236 /// NMake/Jom. 237 /// 238 /// BSD Make is the simplest case: It does no escaping at all. This means 239 /// characters that are normally delimiters, i.e. space and # (the comment 240 /// character) simply aren't supported in filenames. 241 /// 242 /// GNU Make does allow space and # in filenames, but to avoid being treated 243 /// as a delimiter or comment, these must be escaped with a backslash. Because 244 /// backslash is itself the escape character, if a backslash appears in a 245 /// filename, it should be escaped as well. (As a special case, $ is escaped 246 /// as $$, which is the normal Make way to handle the $ character.) 247 /// For compatibility with BSD Make and historical practice, if GNU Make 248 /// un-escapes characters in a filename but doesn't find a match, it will 249 /// retry with the unmodified original string. 250 /// 251 /// GCC tries to accommodate both Make formats by escaping any space or # 252 /// characters in the original filename, but not escaping backslashes. The 253 /// apparent intent is so that filenames with backslashes will be handled 254 /// correctly by BSD Make, and by GNU Make in its fallback mode of using the 255 /// unmodified original string; filenames with # or space characters aren't 256 /// supported by BSD Make at all, but will be handled correctly by GNU Make 257 /// due to the escaping. 258 /// 259 /// A corner case that GCC gets only partly right is when the original filename 260 /// has a backslash immediately followed by space or #. GNU Make would expect 261 /// this backslash to be escaped; however GCC escapes the original backslash 262 /// only when followed by space, not #. It will therefore take a dependency 263 /// from a directive such as 264 /// #include "a\ b\#c.h" 265 /// and emit it as 266 /// a\\\ b\\#c.h 267 /// which GNU Make will interpret as 268 /// a\ b\ 269 /// followed by a comment. Failing to find this file, it will fall back to the 270 /// original string, which probably doesn't exist either; in any case it won't 271 /// find 272 /// a\ b\#c.h 273 /// which is the actual filename specified by the include directive. 274 /// 275 /// Clang does what GCC does, rather than what GNU Make expects. 276 /// 277 /// NMake/Jom has a different set of scary characters, but wraps filespecs in 278 /// double-quotes to avoid misinterpreting them; see 279 /// https://msdn.microsoft.com/en-us/library/dd9y37ha.aspx for NMake info, 280 /// https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx 281 /// for Windows file-naming info. 282 static void PrintFilename(raw_ostream &OS, StringRef Filename, 283 DependencyOutputFormat OutputFormat) { 284 // Convert filename to platform native path 285 llvm::SmallString<256> NativePath; 286 llvm::sys::path::native(Filename.str(), NativePath); 287 288 if (OutputFormat == DependencyOutputFormat::NMake) { 289 // Add quotes if needed. These are the characters listed as "special" to 290 // NMake, that are legal in a Windows filespec, and that could cause 291 // misinterpretation of the dependency string. 292 if (NativePath.find_first_of(" #${}^!") != StringRef::npos) 293 OS << '\"' << NativePath << '\"'; 294 else 295 OS << NativePath; 296 return; 297 } 298 assert(OutputFormat == DependencyOutputFormat::Make); 299 for (unsigned i = 0, e = NativePath.size(); i != e; ++i) { 300 if (NativePath[i] == '#') // Handle '#' the broken gcc way. 301 OS << '\\'; 302 else if (NativePath[i] == ' ') { // Handle space correctly. 303 OS << '\\'; 304 unsigned j = i; 305 while (j > 0 && NativePath[--j] == '\\') 306 OS << '\\'; 307 } else if (NativePath[i] == '$') // $ is escaped by $$. 308 OS << '$'; 309 OS << NativePath[i]; 310 } 311 } 312 313 void DependencyFileGenerator::outputDependencyFile(DiagnosticsEngine &Diags) { 314 if (SeenMissingHeader) { 315 llvm::sys::fs::remove(OutputFile); 316 return; 317 } 318 319 std::error_code EC; 320 llvm::raw_fd_ostream OS(OutputFile, EC, llvm::sys::fs::OF_TextWithCRLF); 321 if (EC) { 322 Diags.Report(diag::err_fe_error_opening) << OutputFile << EC.message(); 323 return; 324 } 325 326 outputDependencyFile(OS); 327 } 328 329 void DependencyFileGenerator::outputDependencyFile(llvm::raw_ostream &OS) { 330 // Write out the dependency targets, trying to avoid overly long 331 // lines when possible. We try our best to emit exactly the same 332 // dependency file as GCC (4.2), assuming the included files are the 333 // same. 334 const unsigned MaxColumns = 75; 335 unsigned Columns = 0; 336 337 for (StringRef Target : Targets) { 338 unsigned N = Target.size(); 339 if (Columns == 0) { 340 Columns += N; 341 } else if (Columns + N + 2 > MaxColumns) { 342 Columns = N + 2; 343 OS << " \\\n "; 344 } else { 345 Columns += N + 1; 346 OS << ' '; 347 } 348 // Targets already quoted as needed. 349 OS << Target; 350 } 351 352 OS << ':'; 353 Columns += 1; 354 355 // Now add each dependency in the order it was seen, but avoiding 356 // duplicates. 357 ArrayRef<std::string> Files = getDependencies(); 358 for (StringRef File : Files) { 359 // Start a new line if this would exceed the column limit. Make 360 // sure to leave space for a trailing " \" in case we need to 361 // break the line on the next iteration. 362 unsigned N = File.size(); 363 if (Columns + (N + 1) + 2 > MaxColumns) { 364 OS << " \\\n "; 365 Columns = 2; 366 } 367 OS << ' '; 368 PrintFilename(OS, File, OutputFormat); 369 Columns += N + 1; 370 } 371 OS << '\n'; 372 373 // Create phony targets if requested. 374 if (PhonyTarget && !Files.empty()) { 375 unsigned Index = 0; 376 for (auto I = Files.begin(), E = Files.end(); I != E; ++I) { 377 if (Index++ == InputFileIndex) 378 continue; 379 OS << '\n'; 380 PrintFilename(OS, *I, OutputFormat); 381 OS << ":\n"; 382 } 383 } 384 } 385