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 Filename == "<built-in>"; 164 } 165 166 bool DependencyCollector::sawDependency(StringRef Filename, bool FromModule, 167 bool IsSystem, bool IsModuleFile, 168 bool IsMissing) { 169 return !isSpecialFilename(Filename) && 170 (needSystemDependencies() || !IsSystem); 171 } 172 173 DependencyCollector::~DependencyCollector() { } 174 void DependencyCollector::attachToPreprocessor(Preprocessor &PP) { 175 PP.addPPCallbacks(std::make_unique<DepCollectorPPCallbacks>(*this, PP)); 176 PP.getHeaderSearchInfo().getModuleMap().addModuleMapCallbacks( 177 std::make_unique<DepCollectorMMCallbacks>(*this)); 178 } 179 void DependencyCollector::attachToASTReader(ASTReader &R) { 180 R.addListener(std::make_unique<DepCollectorASTListener>(*this)); 181 } 182 183 DependencyFileGenerator::DependencyFileGenerator( 184 const DependencyOutputOptions &Opts) 185 : OutputFile(Opts.OutputFile), Targets(Opts.Targets), 186 IncludeSystemHeaders(Opts.IncludeSystemHeaders), 187 PhonyTarget(Opts.UsePhonyTargets), 188 AddMissingHeaderDeps(Opts.AddMissingHeaderDeps), SeenMissingHeader(false), 189 IncludeModuleFiles(Opts.IncludeModuleFiles), 190 OutputFormat(Opts.OutputFormat), InputFileIndex(0) { 191 for (const auto &ExtraDep : Opts.ExtraDeps) { 192 if (addDependency(ExtraDep.first)) 193 ++InputFileIndex; 194 } 195 } 196 197 void DependencyFileGenerator::attachToPreprocessor(Preprocessor &PP) { 198 // Disable the "file not found" diagnostic if the -MG option was given. 199 if (AddMissingHeaderDeps) 200 PP.SetSuppressIncludeNotFoundError(true); 201 202 DependencyCollector::attachToPreprocessor(PP); 203 } 204 205 bool DependencyFileGenerator::sawDependency(StringRef Filename, bool FromModule, 206 bool IsSystem, bool IsModuleFile, 207 bool IsMissing) { 208 if (IsMissing) { 209 // Handle the case of missing file from an inclusion directive. 210 if (AddMissingHeaderDeps) 211 return true; 212 SeenMissingHeader = true; 213 return false; 214 } 215 if (IsModuleFile && !IncludeModuleFiles) 216 return false; 217 218 if (isSpecialFilename(Filename)) 219 return false; 220 221 if (IncludeSystemHeaders) 222 return true; 223 224 return !IsSystem; 225 } 226 227 void DependencyFileGenerator::finishedMainFile(DiagnosticsEngine &Diags) { 228 outputDependencyFile(Diags); 229 } 230 231 /// Print the filename, with escaping or quoting that accommodates the three 232 /// most likely tools that use dependency files: GNU Make, BSD Make, and 233 /// NMake/Jom. 234 /// 235 /// BSD Make is the simplest case: It does no escaping at all. This means 236 /// characters that are normally delimiters, i.e. space and # (the comment 237 /// character) simply aren't supported in filenames. 238 /// 239 /// GNU Make does allow space and # in filenames, but to avoid being treated 240 /// as a delimiter or comment, these must be escaped with a backslash. Because 241 /// backslash is itself the escape character, if a backslash appears in a 242 /// filename, it should be escaped as well. (As a special case, $ is escaped 243 /// as $$, which is the normal Make way to handle the $ character.) 244 /// For compatibility with BSD Make and historical practice, if GNU Make 245 /// un-escapes characters in a filename but doesn't find a match, it will 246 /// retry with the unmodified original string. 247 /// 248 /// GCC tries to accommodate both Make formats by escaping any space or # 249 /// characters in the original filename, but not escaping backslashes. The 250 /// apparent intent is so that filenames with backslashes will be handled 251 /// correctly by BSD Make, and by GNU Make in its fallback mode of using the 252 /// unmodified original string; filenames with # or space characters aren't 253 /// supported by BSD Make at all, but will be handled correctly by GNU Make 254 /// due to the escaping. 255 /// 256 /// A corner case that GCC gets only partly right is when the original filename 257 /// has a backslash immediately followed by space or #. GNU Make would expect 258 /// this backslash to be escaped; however GCC escapes the original backslash 259 /// only when followed by space, not #. It will therefore take a dependency 260 /// from a directive such as 261 /// #include "a\ b\#c.h" 262 /// and emit it as 263 /// a\\\ b\\#c.h 264 /// which GNU Make will interpret as 265 /// a\ b\ 266 /// followed by a comment. Failing to find this file, it will fall back to the 267 /// original string, which probably doesn't exist either; in any case it won't 268 /// find 269 /// a\ b\#c.h 270 /// which is the actual filename specified by the include directive. 271 /// 272 /// Clang does what GCC does, rather than what GNU Make expects. 273 /// 274 /// NMake/Jom has a different set of scary characters, but wraps filespecs in 275 /// double-quotes to avoid misinterpreting them; see 276 /// https://msdn.microsoft.com/en-us/library/dd9y37ha.aspx for NMake info, 277 /// https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx 278 /// for Windows file-naming info. 279 static void PrintFilename(raw_ostream &OS, StringRef Filename, 280 DependencyOutputFormat OutputFormat) { 281 // Convert filename to platform native path 282 llvm::SmallString<256> NativePath; 283 llvm::sys::path::native(Filename.str(), NativePath); 284 285 if (OutputFormat == DependencyOutputFormat::NMake) { 286 // Add quotes if needed. These are the characters listed as "special" to 287 // NMake, that are legal in a Windows filespec, and that could cause 288 // misinterpretation of the dependency string. 289 if (NativePath.find_first_of(" #${}^!") != StringRef::npos) 290 OS << '\"' << NativePath << '\"'; 291 else 292 OS << NativePath; 293 return; 294 } 295 assert(OutputFormat == DependencyOutputFormat::Make); 296 for (unsigned i = 0, e = NativePath.size(); i != e; ++i) { 297 if (NativePath[i] == '#') // Handle '#' the broken gcc way. 298 OS << '\\'; 299 else if (NativePath[i] == ' ') { // Handle space correctly. 300 OS << '\\'; 301 unsigned j = i; 302 while (j > 0 && NativePath[--j] == '\\') 303 OS << '\\'; 304 } else if (NativePath[i] == '$') // $ is escaped by $$. 305 OS << '$'; 306 OS << NativePath[i]; 307 } 308 } 309 310 void DependencyFileGenerator::outputDependencyFile(DiagnosticsEngine &Diags) { 311 if (SeenMissingHeader) { 312 llvm::sys::fs::remove(OutputFile); 313 return; 314 } 315 316 std::error_code EC; 317 llvm::raw_fd_ostream OS(OutputFile, EC, llvm::sys::fs::OF_TextWithCRLF); 318 if (EC) { 319 Diags.Report(diag::err_fe_error_opening) << OutputFile << EC.message(); 320 return; 321 } 322 323 outputDependencyFile(OS); 324 } 325 326 void DependencyFileGenerator::outputDependencyFile(llvm::raw_ostream &OS) { 327 // Write out the dependency targets, trying to avoid overly long 328 // lines when possible. We try our best to emit exactly the same 329 // dependency file as GCC>=10, assuming the included files are the 330 // same. 331 const unsigned MaxColumns = 75; 332 unsigned Columns = 0; 333 334 for (StringRef Target : Targets) { 335 unsigned N = Target.size(); 336 if (Columns == 0) { 337 Columns += N; 338 } else if (Columns + N + 2 > MaxColumns) { 339 Columns = N + 2; 340 OS << " \\\n "; 341 } else { 342 Columns += N + 1; 343 OS << ' '; 344 } 345 // Targets already quoted as needed. 346 OS << Target; 347 } 348 349 OS << ':'; 350 Columns += 1; 351 352 // Now add each dependency in the order it was seen, but avoiding 353 // duplicates. 354 ArrayRef<std::string> Files = getDependencies(); 355 for (StringRef File : Files) { 356 if (File == "<stdin>") 357 continue; 358 // Start a new line if this would exceed the column limit. Make 359 // sure to leave space for a trailing " \" in case we need to 360 // break the line on the next iteration. 361 unsigned N = File.size(); 362 if (Columns + (N + 1) + 2 > MaxColumns) { 363 OS << " \\\n "; 364 Columns = 2; 365 } 366 OS << ' '; 367 PrintFilename(OS, File, OutputFormat); 368 Columns += N + 1; 369 } 370 OS << '\n'; 371 372 // Create phony targets if requested. 373 if (PhonyTarget && !Files.empty()) { 374 unsigned Index = 0; 375 for (auto I = Files.begin(), E = Files.end(); I != E; ++I) { 376 if (Index++ == InputFileIndex) 377 continue; 378 PrintFilename(OS, *I, OutputFormat); 379 OS << ":\n"; 380 } 381 } 382 } 383