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/LexDiagnostic.h"
21 #include "clang/Lex/ModuleMap.h"
22 #include "clang/Lex/PPCallbacks.h"
23 #include "clang/Lex/Preprocessor.h"
24 #include "clang/Serialization/ASTReader.h"
25 #include "llvm/ADT/StringSet.h"
26 #include "llvm/ADT/StringSwitch.h"
27 #include "llvm/Support/FileSystem.h"
28 #include "llvm/Support/Path.h"
29 #include "llvm/Support/raw_ostream.h"
30
31 using namespace clang;
32
33 namespace {
34 struct DepCollectorPPCallbacks : public PPCallbacks {
35 DependencyCollector &DepCollector;
36 SourceManager &SM;
DepCollectorPPCallbacks__anon6417ed290111::DepCollectorPPCallbacks37 DepCollectorPPCallbacks(DependencyCollector &L, SourceManager &SM)
38 : DepCollector(L), SM(SM) { }
39
FileChanged__anon6417ed290111::DepCollectorPPCallbacks40 void FileChanged(SourceLocation Loc, FileChangeReason Reason,
41 SrcMgr::CharacteristicKind FileType,
42 FileID PrevFID) override {
43 if (Reason != PPCallbacks::EnterFile)
44 return;
45
46 // Dependency generation really does want to go all the way to the
47 // file entry for a source location to find out what is depended on.
48 // We do not want #line markers to affect dependency generation!
49 const FileEntry *FE =
50 SM.getFileEntryForID(SM.getFileID(SM.getExpansionLoc(Loc)));
51 if (!FE)
52 return;
53
54 StringRef Filename =
55 llvm::sys::path::remove_leading_dotslash(FE->getName());
56
57 DepCollector.maybeAddDependency(Filename, /*FromModule*/false,
58 FileType != SrcMgr::C_User,
59 /*IsModuleFile*/false, /*IsMissing*/false);
60 }
61
InclusionDirective__anon6417ed290111::DepCollectorPPCallbacks62 void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
63 StringRef FileName, bool IsAngled,
64 CharSourceRange FilenameRange, const FileEntry *File,
65 StringRef SearchPath, StringRef RelativePath,
66 const Module *Imported) override {
67 if (!File)
68 DepCollector.maybeAddDependency(FileName, /*FromModule*/false,
69 /*IsSystem*/false, /*IsModuleFile*/false,
70 /*IsMissing*/true);
71 // Files that actually exist are handled by FileChanged.
72 }
73
EndOfMainFile__anon6417ed290111::DepCollectorPPCallbacks74 void EndOfMainFile() override {
75 DepCollector.finishedMainFile();
76 }
77 };
78
79 struct DepCollectorMMCallbacks : public ModuleMapCallbacks {
80 DependencyCollector &DepCollector;
DepCollectorMMCallbacks__anon6417ed290111::DepCollectorMMCallbacks81 DepCollectorMMCallbacks(DependencyCollector &DC) : DepCollector(DC) {}
82
moduleMapFileRead__anon6417ed290111::DepCollectorMMCallbacks83 void moduleMapFileRead(SourceLocation Loc, const FileEntry &Entry,
84 bool IsSystem) override {
85 StringRef Filename = Entry.getName();
86 DepCollector.maybeAddDependency(Filename, /*FromModule*/false,
87 /*IsSystem*/IsSystem,
88 /*IsModuleFile*/false,
89 /*IsMissing*/false);
90 }
91 };
92
93 struct DepCollectorASTListener : public ASTReaderListener {
94 DependencyCollector &DepCollector;
DepCollectorASTListener__anon6417ed290111::DepCollectorASTListener95 DepCollectorASTListener(DependencyCollector &L) : DepCollector(L) { }
needsInputFileVisitation__anon6417ed290111::DepCollectorASTListener96 bool needsInputFileVisitation() override { return true; }
needsSystemInputFileVisitation__anon6417ed290111::DepCollectorASTListener97 bool needsSystemInputFileVisitation() override {
98 return DepCollector.needSystemDependencies();
99 }
visitModuleFile__anon6417ed290111::DepCollectorASTListener100 void visitModuleFile(StringRef Filename,
101 serialization::ModuleKind Kind) override {
102 DepCollector.maybeAddDependency(Filename, /*FromModule*/true,
103 /*IsSystem*/false, /*IsModuleFile*/true,
104 /*IsMissing*/false);
105 }
visitInputFile__anon6417ed290111::DepCollectorASTListener106 bool visitInputFile(StringRef Filename, bool IsSystem,
107 bool IsOverridden, bool IsExplicitModule) override {
108 if (IsOverridden || IsExplicitModule)
109 return true;
110
111 DepCollector.maybeAddDependency(Filename, /*FromModule*/true, IsSystem,
112 /*IsModuleFile*/false, /*IsMissing*/false);
113 return true;
114 }
115 };
116 } // end anonymous namespace
117
maybeAddDependency(StringRef Filename,bool FromModule,bool IsSystem,bool IsModuleFile,bool IsMissing)118 void DependencyCollector::maybeAddDependency(StringRef Filename, bool FromModule,
119 bool IsSystem, bool IsModuleFile,
120 bool IsMissing) {
121 if (Seen.insert(Filename).second &&
122 sawDependency(Filename, FromModule, IsSystem, IsModuleFile, IsMissing))
123 Dependencies.push_back(Filename);
124 }
125
isSpecialFilename(StringRef Filename)126 static bool isSpecialFilename(StringRef Filename) {
127 return llvm::StringSwitch<bool>(Filename)
128 .Case("<built-in>", true)
129 .Case("<stdin>", true)
130 .Default(false);
131 }
132
sawDependency(StringRef Filename,bool FromModule,bool IsSystem,bool IsModuleFile,bool IsMissing)133 bool DependencyCollector::sawDependency(StringRef Filename, bool FromModule,
134 bool IsSystem, bool IsModuleFile,
135 bool IsMissing) {
136 return !isSpecialFilename(Filename) &&
137 (needSystemDependencies() || !IsSystem);
138 }
139
~DependencyCollector()140 DependencyCollector::~DependencyCollector() { }
attachToPreprocessor(Preprocessor & PP)141 void DependencyCollector::attachToPreprocessor(Preprocessor &PP) {
142 PP.addPPCallbacks(
143 llvm::make_unique<DepCollectorPPCallbacks>(*this, PP.getSourceManager()));
144 PP.getHeaderSearchInfo().getModuleMap().addModuleMapCallbacks(
145 llvm::make_unique<DepCollectorMMCallbacks>(*this));
146 }
attachToASTReader(ASTReader & R)147 void DependencyCollector::attachToASTReader(ASTReader &R) {
148 R.addListener(llvm::make_unique<DepCollectorASTListener>(*this));
149 }
150
151 namespace {
152 /// Private implementation for DependencyFileGenerator
153 class DFGImpl : public PPCallbacks {
154 std::vector<std::string> Files;
155 llvm::StringSet<> FilesSet;
156 const Preprocessor *PP;
157 std::string OutputFile;
158 std::vector<std::string> Targets;
159 bool IncludeSystemHeaders;
160 bool PhonyTarget;
161 bool AddMissingHeaderDeps;
162 bool SeenMissingHeader;
163 bool IncludeModuleFiles;
164 DependencyOutputFormat OutputFormat;
165
166 private:
167 bool FileMatchesDepCriteria(const char *Filename,
168 SrcMgr::CharacteristicKind FileType);
169 void OutputDependencyFile();
170
171 public:
DFGImpl(const Preprocessor * _PP,const DependencyOutputOptions & Opts)172 DFGImpl(const Preprocessor *_PP, const DependencyOutputOptions &Opts)
173 : PP(_PP), OutputFile(Opts.OutputFile), Targets(Opts.Targets),
174 IncludeSystemHeaders(Opts.IncludeSystemHeaders),
175 PhonyTarget(Opts.UsePhonyTargets),
176 AddMissingHeaderDeps(Opts.AddMissingHeaderDeps),
177 SeenMissingHeader(false),
178 IncludeModuleFiles(Opts.IncludeModuleFiles),
179 OutputFormat(Opts.OutputFormat) {
180 for (const auto &ExtraDep : Opts.ExtraDeps) {
181 AddFilename(ExtraDep);
182 }
183 }
184
185 void FileChanged(SourceLocation Loc, FileChangeReason Reason,
186 SrcMgr::CharacteristicKind FileType,
187 FileID PrevFID) override;
188 void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
189 StringRef FileName, bool IsAngled,
190 CharSourceRange FilenameRange, const FileEntry *File,
191 StringRef SearchPath, StringRef RelativePath,
192 const Module *Imported) override;
193
EndOfMainFile()194 void EndOfMainFile() override {
195 OutputDependencyFile();
196 }
197
198 void AddFilename(StringRef Filename);
includeSystemHeaders() const199 bool includeSystemHeaders() const { return IncludeSystemHeaders; }
includeModuleFiles() const200 bool includeModuleFiles() const { return IncludeModuleFiles; }
201 };
202
203 class DFGMMCallback : public ModuleMapCallbacks {
204 DFGImpl &Parent;
205 public:
DFGMMCallback(DFGImpl & Parent)206 DFGMMCallback(DFGImpl &Parent) : Parent(Parent) {}
moduleMapFileRead(SourceLocation Loc,const FileEntry & Entry,bool IsSystem)207 void moduleMapFileRead(SourceLocation Loc, const FileEntry &Entry,
208 bool IsSystem) override {
209 if (!IsSystem || Parent.includeSystemHeaders())
210 Parent.AddFilename(Entry.getName());
211 }
212 };
213
214 class DFGASTReaderListener : public ASTReaderListener {
215 DFGImpl &Parent;
216 public:
DFGASTReaderListener(DFGImpl & Parent)217 DFGASTReaderListener(DFGImpl &Parent)
218 : Parent(Parent) { }
needsInputFileVisitation()219 bool needsInputFileVisitation() override { return true; }
needsSystemInputFileVisitation()220 bool needsSystemInputFileVisitation() override {
221 return Parent.includeSystemHeaders();
222 }
223 void visitModuleFile(StringRef Filename,
224 serialization::ModuleKind Kind) override;
225 bool visitInputFile(StringRef Filename, bool isSystem,
226 bool isOverridden, bool isExplicitModule) override;
227 };
228 }
229
DependencyFileGenerator(void * Impl)230 DependencyFileGenerator::DependencyFileGenerator(void *Impl)
231 : Impl(Impl) { }
232
CreateAndAttachToPreprocessor(clang::Preprocessor & PP,const clang::DependencyOutputOptions & Opts)233 DependencyFileGenerator *DependencyFileGenerator::CreateAndAttachToPreprocessor(
234 clang::Preprocessor &PP, const clang::DependencyOutputOptions &Opts) {
235
236 if (Opts.Targets.empty()) {
237 PP.getDiagnostics().Report(diag::err_fe_dependency_file_requires_MT);
238 return nullptr;
239 }
240
241 // Disable the "file not found" diagnostic if the -MG option was given.
242 if (Opts.AddMissingHeaderDeps)
243 PP.SetSuppressIncludeNotFoundError(true);
244
245 DFGImpl *Callback = new DFGImpl(&PP, Opts);
246 PP.addPPCallbacks(std::unique_ptr<PPCallbacks>(Callback));
247 PP.getHeaderSearchInfo().getModuleMap().addModuleMapCallbacks(
248 llvm::make_unique<DFGMMCallback>(*Callback));
249 return new DependencyFileGenerator(Callback);
250 }
251
AttachToASTReader(ASTReader & R)252 void DependencyFileGenerator::AttachToASTReader(ASTReader &R) {
253 DFGImpl *I = reinterpret_cast<DFGImpl *>(Impl);
254 assert(I && "missing implementation");
255 R.addListener(llvm::make_unique<DFGASTReaderListener>(*I));
256 }
257
258 /// FileMatchesDepCriteria - Determine whether the given Filename should be
259 /// considered as a dependency.
FileMatchesDepCriteria(const char * Filename,SrcMgr::CharacteristicKind FileType)260 bool DFGImpl::FileMatchesDepCriteria(const char *Filename,
261 SrcMgr::CharacteristicKind FileType) {
262 if (isSpecialFilename(Filename))
263 return false;
264
265 if (IncludeSystemHeaders)
266 return true;
267
268 return FileType == SrcMgr::C_User;
269 }
270
FileChanged(SourceLocation Loc,FileChangeReason Reason,SrcMgr::CharacteristicKind FileType,FileID PrevFID)271 void DFGImpl::FileChanged(SourceLocation Loc,
272 FileChangeReason Reason,
273 SrcMgr::CharacteristicKind FileType,
274 FileID PrevFID) {
275 if (Reason != PPCallbacks::EnterFile)
276 return;
277
278 // Dependency generation really does want to go all the way to the
279 // file entry for a source location to find out what is depended on.
280 // We do not want #line markers to affect dependency generation!
281 SourceManager &SM = PP->getSourceManager();
282
283 const FileEntry *FE =
284 SM.getFileEntryForID(SM.getFileID(SM.getExpansionLoc(Loc)));
285 if (!FE) return;
286
287 StringRef Filename = FE->getName();
288 if (!FileMatchesDepCriteria(Filename.data(), FileType))
289 return;
290
291 AddFilename(llvm::sys::path::remove_leading_dotslash(Filename));
292 }
293
InclusionDirective(SourceLocation HashLoc,const Token & IncludeTok,StringRef FileName,bool IsAngled,CharSourceRange FilenameRange,const FileEntry * File,StringRef SearchPath,StringRef RelativePath,const Module * Imported)294 void DFGImpl::InclusionDirective(SourceLocation HashLoc,
295 const Token &IncludeTok,
296 StringRef FileName,
297 bool IsAngled,
298 CharSourceRange FilenameRange,
299 const FileEntry *File,
300 StringRef SearchPath,
301 StringRef RelativePath,
302 const Module *Imported) {
303 if (!File) {
304 if (AddMissingHeaderDeps)
305 AddFilename(FileName);
306 else
307 SeenMissingHeader = true;
308 }
309 }
310
AddFilename(StringRef Filename)311 void DFGImpl::AddFilename(StringRef Filename) {
312 if (FilesSet.insert(Filename).second)
313 Files.push_back(Filename);
314 }
315
316 /// Print the filename, with escaping or quoting that accommodates the three
317 /// most likely tools that use dependency files: GNU Make, BSD Make, and
318 /// NMake/Jom.
319 ///
320 /// BSD Make is the simplest case: It does no escaping at all. This means
321 /// characters that are normally delimiters, i.e. space and # (the comment
322 /// character) simply aren't supported in filenames.
323 ///
324 /// GNU Make does allow space and # in filenames, but to avoid being treated
325 /// as a delimiter or comment, these must be escaped with a backslash. Because
326 /// backslash is itself the escape character, if a backslash appears in a
327 /// filename, it should be escaped as well. (As a special case, $ is escaped
328 /// as $$, which is the normal Make way to handle the $ character.)
329 /// For compatibility with BSD Make and historical practice, if GNU Make
330 /// un-escapes characters in a filename but doesn't find a match, it will
331 /// retry with the unmodified original string.
332 ///
333 /// GCC tries to accommodate both Make formats by escaping any space or #
334 /// characters in the original filename, but not escaping backslashes. The
335 /// apparent intent is so that filenames with backslashes will be handled
336 /// correctly by BSD Make, and by GNU Make in its fallback mode of using the
337 /// unmodified original string; filenames with # or space characters aren't
338 /// supported by BSD Make at all, but will be handled correctly by GNU Make
339 /// due to the escaping.
340 ///
341 /// A corner case that GCC gets only partly right is when the original filename
342 /// has a backslash immediately followed by space or #. GNU Make would expect
343 /// this backslash to be escaped; however GCC escapes the original backslash
344 /// only when followed by space, not #. It will therefore take a dependency
345 /// from a directive such as
346 /// #include "a\ b\#c.h"
347 /// and emit it as
348 /// a\\\ b\\#c.h
349 /// which GNU Make will interpret as
350 /// a\ b\
351 /// followed by a comment. Failing to find this file, it will fall back to the
352 /// original string, which probably doesn't exist either; in any case it won't
353 /// find
354 /// a\ b\#c.h
355 /// which is the actual filename specified by the include directive.
356 ///
357 /// Clang does what GCC does, rather than what GNU Make expects.
358 ///
359 /// NMake/Jom has a different set of scary characters, but wraps filespecs in
360 /// double-quotes to avoid misinterpreting them; see
361 /// https://msdn.microsoft.com/en-us/library/dd9y37ha.aspx for NMake info,
362 /// https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx
363 /// for Windows file-naming info.
PrintFilename(raw_ostream & OS,StringRef Filename,DependencyOutputFormat OutputFormat)364 static void PrintFilename(raw_ostream &OS, StringRef Filename,
365 DependencyOutputFormat OutputFormat) {
366 if (OutputFormat == DependencyOutputFormat::NMake) {
367 // Add quotes if needed. These are the characters listed as "special" to
368 // NMake, that are legal in a Windows filespec, and that could cause
369 // misinterpretation of the dependency string.
370 if (Filename.find_first_of(" #${}^!") != StringRef::npos)
371 OS << '\"' << Filename << '\"';
372 else
373 OS << Filename;
374 return;
375 }
376 assert(OutputFormat == DependencyOutputFormat::Make);
377 for (unsigned i = 0, e = Filename.size(); i != e; ++i) {
378 if (Filename[i] == '#') // Handle '#' the broken gcc way.
379 OS << '\\';
380 else if (Filename[i] == ' ') { // Handle space correctly.
381 OS << '\\';
382 unsigned j = i;
383 while (j > 0 && Filename[--j] == '\\')
384 OS << '\\';
385 } else if (Filename[i] == '$') // $ is escaped by $$.
386 OS << '$';
387 OS << Filename[i];
388 }
389 }
390
OutputDependencyFile()391 void DFGImpl::OutputDependencyFile() {
392 if (SeenMissingHeader) {
393 llvm::sys::fs::remove(OutputFile);
394 return;
395 }
396
397 std::error_code EC;
398 llvm::raw_fd_ostream OS(OutputFile, EC, llvm::sys::fs::F_Text);
399 if (EC) {
400 PP->getDiagnostics().Report(diag::err_fe_error_opening) << OutputFile
401 << EC.message();
402 return;
403 }
404
405 // Write out the dependency targets, trying to avoid overly long
406 // lines when possible. We try our best to emit exactly the same
407 // dependency file as GCC (4.2), assuming the included files are the
408 // same.
409 const unsigned MaxColumns = 75;
410 unsigned Columns = 0;
411
412 for (std::vector<std::string>::iterator
413 I = Targets.begin(), E = Targets.end(); I != E; ++I) {
414 unsigned N = I->length();
415 if (Columns == 0) {
416 Columns += N;
417 } else if (Columns + N + 2 > MaxColumns) {
418 Columns = N + 2;
419 OS << " \\\n ";
420 } else {
421 Columns += N + 1;
422 OS << ' ';
423 }
424 // Targets already quoted as needed.
425 OS << *I;
426 }
427
428 OS << ':';
429 Columns += 1;
430
431 // Now add each dependency in the order it was seen, but avoiding
432 // duplicates.
433 for (std::vector<std::string>::iterator I = Files.begin(),
434 E = Files.end(); I != E; ++I) {
435 // Start a new line if this would exceed the column limit. Make
436 // sure to leave space for a trailing " \" in case we need to
437 // break the line on the next iteration.
438 unsigned N = I->length();
439 if (Columns + (N + 1) + 2 > MaxColumns) {
440 OS << " \\\n ";
441 Columns = 2;
442 }
443 OS << ' ';
444 PrintFilename(OS, *I, OutputFormat);
445 Columns += N + 1;
446 }
447 OS << '\n';
448
449 // Create phony targets if requested.
450 if (PhonyTarget && !Files.empty()) {
451 // Skip the first entry, this is always the input file itself.
452 for (std::vector<std::string>::iterator I = Files.begin() + 1,
453 E = Files.end(); I != E; ++I) {
454 OS << '\n';
455 PrintFilename(OS, *I, OutputFormat);
456 OS << ":\n";
457 }
458 }
459 }
460
visitInputFile(llvm::StringRef Filename,bool IsSystem,bool IsOverridden,bool IsExplicitModule)461 bool DFGASTReaderListener::visitInputFile(llvm::StringRef Filename,
462 bool IsSystem, bool IsOverridden,
463 bool IsExplicitModule) {
464 assert(!IsSystem || needsSystemInputFileVisitation());
465 if (IsOverridden || IsExplicitModule)
466 return true;
467
468 Parent.AddFilename(Filename);
469 return true;
470 }
471
visitModuleFile(llvm::StringRef Filename,serialization::ModuleKind Kind)472 void DFGASTReaderListener::visitModuleFile(llvm::StringRef Filename,
473 serialization::ModuleKind Kind) {
474 if (Parent.includeModuleFiles())
475 Parent.AddFilename(Filename);
476 }
477