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/PPCallbacks.h"
22 #include "clang/Lex/Preprocessor.h"
23 #include "clang/Serialization/ASTReader.h"
24 #include "llvm/ADT/StringSet.h"
25 #include "llvm/ADT/StringSwitch.h"
26 #include "llvm/Support/FileSystem.h"
27 #include "llvm/Support/Path.h"
28 #include "llvm/Support/raw_ostream.h"
29 
30 using namespace clang;
31 
32 namespace {
33 struct DepCollectorPPCallbacks : public PPCallbacks {
34   DependencyCollector &DepCollector;
35   SourceManager &SM;
36   DepCollectorPPCallbacks(DependencyCollector &L, SourceManager &SM)
37       : DepCollector(L), SM(SM) { }
38 
39   void FileChanged(SourceLocation Loc, FileChangeReason Reason,
40                    SrcMgr::CharacteristicKind FileType,
41                    FileID PrevFID) override {
42     if (Reason != PPCallbacks::EnterFile)
43       return;
44 
45     // Dependency generation really does want to go all the way to the
46     // file entry for a source location to find out what is depended on.
47     // We do not want #line markers to affect dependency generation!
48     const FileEntry *FE =
49         SM.getFileEntryForID(SM.getFileID(SM.getExpansionLoc(Loc)));
50     if (!FE)
51       return;
52 
53     StringRef Filename = FE->getName();
54 
55     // Remove leading "./" (or ".//" or "././" etc.)
56     while (Filename.size() > 2 && Filename[0] == '.' &&
57            llvm::sys::path::is_separator(Filename[1])) {
58       Filename = Filename.substr(1);
59       while (llvm::sys::path::is_separator(Filename[0]))
60         Filename = Filename.substr(1);
61     }
62 
63     DepCollector.maybeAddDependency(Filename, /*FromModule*/false,
64                                    FileType != SrcMgr::C_User,
65                                    /*IsModuleFile*/false, /*IsMissing*/false);
66   }
67 
68   void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
69                           StringRef FileName, bool IsAngled,
70                           CharSourceRange FilenameRange, const FileEntry *File,
71                           StringRef SearchPath, StringRef RelativePath,
72                           const Module *Imported) override {
73     if (!File)
74       DepCollector.maybeAddDependency(FileName, /*FromModule*/false,
75                                      /*IsSystem*/false, /*IsModuleFile*/false,
76                                      /*IsMissing*/true);
77     // Files that actually exist are handled by FileChanged.
78   }
79 
80   void EndOfMainFile() override {
81     DepCollector.finishedMainFile();
82   }
83 };
84 
85 struct DepCollectorASTListener : public ASTReaderListener {
86   DependencyCollector &DepCollector;
87   DepCollectorASTListener(DependencyCollector &L) : DepCollector(L) { }
88   bool needsInputFileVisitation() override { return true; }
89   bool needsSystemInputFileVisitation() override {
90     return DepCollector.needSystemDependencies();
91   }
92   void visitModuleFile(StringRef Filename) override {
93     DepCollector.maybeAddDependency(Filename, /*FromModule*/true,
94                                    /*IsSystem*/false, /*IsModuleFile*/true,
95                                    /*IsMissing*/false);
96   }
97   bool visitInputFile(StringRef Filename, bool IsSystem,
98                       bool IsOverridden) override {
99     if (IsOverridden)
100       return true;
101 
102     DepCollector.maybeAddDependency(Filename, /*FromModule*/true, IsSystem,
103                                    /*IsModuleFile*/false, /*IsMissing*/false);
104     return true;
105   }
106 };
107 } // end anonymous namespace
108 
109 void DependencyCollector::maybeAddDependency(StringRef Filename, bool FromModule,
110                                             bool IsSystem, bool IsModuleFile,
111                                             bool IsMissing) {
112   if (Seen.insert(Filename).second &&
113       sawDependency(Filename, FromModule, IsSystem, IsModuleFile, IsMissing))
114     Dependencies.push_back(Filename);
115 }
116 
117 static bool isSpecialFilename(StringRef Filename) {
118   return llvm::StringSwitch<bool>(Filename)
119       .Case("<built-in>", true)
120       .Case("<stdin>", true)
121       .Default(false);
122 }
123 
124 bool DependencyCollector::sawDependency(StringRef Filename, bool FromModule,
125                                        bool IsSystem, bool IsModuleFile,
126                                        bool IsMissing) {
127   return !isSpecialFilename(Filename) &&
128          (needSystemDependencies() || !IsSystem);
129 }
130 
131 DependencyCollector::~DependencyCollector() { }
132 void DependencyCollector::attachToPreprocessor(Preprocessor &PP) {
133   PP.addPPCallbacks(
134       llvm::make_unique<DepCollectorPPCallbacks>(*this, PP.getSourceManager()));
135 }
136 void DependencyCollector::attachToASTReader(ASTReader &R) {
137   R.addListener(llvm::make_unique<DepCollectorASTListener>(*this));
138 }
139 
140 namespace {
141 /// Private implementation for DependencyFileGenerator
142 class DFGImpl : public PPCallbacks {
143   std::vector<std::string> Files;
144   llvm::StringSet<> FilesSet;
145   const Preprocessor *PP;
146   std::string OutputFile;
147   std::vector<std::string> Targets;
148   bool IncludeSystemHeaders;
149   bool PhonyTarget;
150   bool AddMissingHeaderDeps;
151   bool SeenMissingHeader;
152   bool IncludeModuleFiles;
153   DependencyOutputFormat OutputFormat;
154 
155 private:
156   bool FileMatchesDepCriteria(const char *Filename,
157                               SrcMgr::CharacteristicKind FileType);
158   void OutputDependencyFile();
159 
160 public:
161   DFGImpl(const Preprocessor *_PP, const DependencyOutputOptions &Opts)
162     : PP(_PP), OutputFile(Opts.OutputFile), Targets(Opts.Targets),
163       IncludeSystemHeaders(Opts.IncludeSystemHeaders),
164       PhonyTarget(Opts.UsePhonyTargets),
165       AddMissingHeaderDeps(Opts.AddMissingHeaderDeps),
166       SeenMissingHeader(false),
167       IncludeModuleFiles(Opts.IncludeModuleFiles),
168       OutputFormat(Opts.OutputFormat) {}
169 
170   void FileChanged(SourceLocation Loc, FileChangeReason Reason,
171                    SrcMgr::CharacteristicKind FileType,
172                    FileID PrevFID) override;
173   void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
174                           StringRef FileName, bool IsAngled,
175                           CharSourceRange FilenameRange, const FileEntry *File,
176                           StringRef SearchPath, StringRef RelativePath,
177                           const Module *Imported) override;
178 
179   void EndOfMainFile() override {
180     OutputDependencyFile();
181   }
182 
183   void AddFilename(StringRef Filename);
184   bool includeSystemHeaders() const { return IncludeSystemHeaders; }
185   bool includeModuleFiles() const { return IncludeModuleFiles; }
186 };
187 
188 class DFGASTReaderListener : public ASTReaderListener {
189   DFGImpl &Parent;
190 public:
191   DFGASTReaderListener(DFGImpl &Parent)
192   : Parent(Parent) { }
193   bool needsInputFileVisitation() override { return true; }
194   bool needsSystemInputFileVisitation() override {
195     return Parent.includeSystemHeaders();
196   }
197   void visitModuleFile(StringRef Filename) override;
198   bool visitInputFile(StringRef Filename, bool isSystem,
199                       bool isOverridden) override;
200 };
201 }
202 
203 DependencyFileGenerator::DependencyFileGenerator(void *Impl)
204 : Impl(Impl) { }
205 
206 DependencyFileGenerator *DependencyFileGenerator::CreateAndAttachToPreprocessor(
207     clang::Preprocessor &PP, const clang::DependencyOutputOptions &Opts) {
208 
209   if (Opts.Targets.empty()) {
210     PP.getDiagnostics().Report(diag::err_fe_dependency_file_requires_MT);
211     return nullptr;
212   }
213 
214   // Disable the "file not found" diagnostic if the -MG option was given.
215   if (Opts.AddMissingHeaderDeps)
216     PP.SetSuppressIncludeNotFoundError(true);
217 
218   DFGImpl *Callback = new DFGImpl(&PP, Opts);
219   PP.addPPCallbacks(std::unique_ptr<PPCallbacks>(Callback));
220   return new DependencyFileGenerator(Callback);
221 }
222 
223 void DependencyFileGenerator::AttachToASTReader(ASTReader &R) {
224   DFGImpl *I = reinterpret_cast<DFGImpl *>(Impl);
225   assert(I && "missing implementation");
226   R.addListener(llvm::make_unique<DFGASTReaderListener>(*I));
227 }
228 
229 /// FileMatchesDepCriteria - Determine whether the given Filename should be
230 /// considered as a dependency.
231 bool DFGImpl::FileMatchesDepCriteria(const char *Filename,
232                                      SrcMgr::CharacteristicKind FileType) {
233   if (isSpecialFilename(Filename))
234     return false;
235 
236   if (IncludeSystemHeaders)
237     return true;
238 
239   return FileType == SrcMgr::C_User;
240 }
241 
242 void DFGImpl::FileChanged(SourceLocation Loc,
243                           FileChangeReason Reason,
244                           SrcMgr::CharacteristicKind FileType,
245                           FileID PrevFID) {
246   if (Reason != PPCallbacks::EnterFile)
247     return;
248 
249   // Dependency generation really does want to go all the way to the
250   // file entry for a source location to find out what is depended on.
251   // We do not want #line markers to affect dependency generation!
252   SourceManager &SM = PP->getSourceManager();
253 
254   const FileEntry *FE =
255     SM.getFileEntryForID(SM.getFileID(SM.getExpansionLoc(Loc)));
256   if (!FE) return;
257 
258   StringRef Filename = FE->getName();
259   if (!FileMatchesDepCriteria(Filename.data(), FileType))
260     return;
261 
262   // Remove leading "./" (or ".//" or "././" etc.)
263   while (Filename.size() > 2 && Filename[0] == '.' &&
264          llvm::sys::path::is_separator(Filename[1])) {
265     Filename = Filename.substr(1);
266     while (llvm::sys::path::is_separator(Filename[0]))
267       Filename = Filename.substr(1);
268   }
269 
270   AddFilename(Filename);
271 }
272 
273 void DFGImpl::InclusionDirective(SourceLocation HashLoc,
274                                  const Token &IncludeTok,
275                                  StringRef FileName,
276                                  bool IsAngled,
277                                  CharSourceRange FilenameRange,
278                                  const FileEntry *File,
279                                  StringRef SearchPath,
280                                  StringRef RelativePath,
281                                  const Module *Imported) {
282   if (!File) {
283     if (AddMissingHeaderDeps)
284       AddFilename(FileName);
285     else
286       SeenMissingHeader = true;
287   }
288 }
289 
290 void DFGImpl::AddFilename(StringRef Filename) {
291   if (FilesSet.insert(Filename).second)
292     Files.push_back(Filename);
293 }
294 
295 /// PrintFilename - GCC escapes spaces, # and $, but apparently not ' or " or
296 /// other scary characters. NMake/Jom has a different set of scary characters,
297 /// but wraps filespecs in double-quotes to avoid misinterpreting them;
298 /// https://msdn.microsoft.com/en-us/library/dd9y37ha.aspx for NMake info,
299 /// https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx
300 /// for Windows file-naming info.
301 static void PrintFilename(raw_ostream &OS, StringRef Filename,
302                           DependencyOutputFormat OutputFormat) {
303   if (OutputFormat == DependencyOutputFormat::NMake) {
304     // Add quotes if needed. These are the characters listed as "special" to
305     // NMake, that are legal in a Windows filespec, and that could cause
306     // misinterpretation of the dependency string.
307     if (Filename.find_first_of(" #${}^!") != StringRef::npos)
308       OS << '\"' << Filename << '\"';
309     else
310       OS << Filename;
311     return;
312   }
313   for (unsigned i = 0, e = Filename.size(); i != e; ++i) {
314     if (Filename[i] == ' ' || Filename[i] == '#')
315       OS << '\\';
316     else if (Filename[i] == '$') // $ is escaped by $$.
317       OS << '$';
318     OS << Filename[i];
319   }
320 }
321 
322 void DFGImpl::OutputDependencyFile() {
323   if (SeenMissingHeader) {
324     llvm::sys::fs::remove(OutputFile);
325     return;
326   }
327 
328   std::error_code EC;
329   llvm::raw_fd_ostream OS(OutputFile, EC, llvm::sys::fs::F_Text);
330   if (EC) {
331     PP->getDiagnostics().Report(diag::err_fe_error_opening) << OutputFile
332                                                             << EC.message();
333     return;
334   }
335 
336   // Write out the dependency targets, trying to avoid overly long
337   // lines when possible. We try our best to emit exactly the same
338   // dependency file as GCC (4.2), assuming the included files are the
339   // same.
340   const unsigned MaxColumns = 75;
341   unsigned Columns = 0;
342 
343   for (std::vector<std::string>::iterator
344          I = Targets.begin(), E = Targets.end(); I != E; ++I) {
345     unsigned N = I->length();
346     if (Columns == 0) {
347       Columns += N;
348     } else if (Columns + N + 2 > MaxColumns) {
349       Columns = N + 2;
350       OS << " \\\n  ";
351     } else {
352       Columns += N + 1;
353       OS << ' ';
354     }
355     // Targets already quoted as needed.
356     OS << *I;
357   }
358 
359   OS << ':';
360   Columns += 1;
361 
362   // Now add each dependency in the order it was seen, but avoiding
363   // duplicates.
364   for (std::vector<std::string>::iterator I = Files.begin(),
365          E = Files.end(); I != E; ++I) {
366     // Start a new line if this would exceed the column limit. Make
367     // sure to leave space for a trailing " \" in case we need to
368     // break the line on the next iteration.
369     unsigned N = I->length();
370     if (Columns + (N + 1) + 2 > MaxColumns) {
371       OS << " \\\n ";
372       Columns = 2;
373     }
374     OS << ' ';
375     PrintFilename(OS, *I, OutputFormat);
376     Columns += N + 1;
377   }
378   OS << '\n';
379 
380   // Create phony targets if requested.
381   if (PhonyTarget && !Files.empty()) {
382     // Skip the first entry, this is always the input file itself.
383     for (std::vector<std::string>::iterator I = Files.begin() + 1,
384            E = Files.end(); I != E; ++I) {
385       OS << '\n';
386       PrintFilename(OS, *I, OutputFormat);
387       OS << ":\n";
388     }
389   }
390 }
391 
392 bool DFGASTReaderListener::visitInputFile(llvm::StringRef Filename,
393                                           bool IsSystem, bool IsOverridden) {
394   assert(!IsSystem || needsSystemInputFileVisitation());
395   if (IsOverridden)
396     return true;
397 
398   Parent.AddFilename(Filename);
399   return true;
400 }
401 
402 void DFGASTReaderListener::visitModuleFile(llvm::StringRef Filename) {
403   if (Parent.includeModuleFiles())
404     Parent.AddFilename(Filename);
405 }
406