clang  11.0.0git
DependencyFile.cpp
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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"
19 #include "clang/Lex/ModuleMap.h"
20 #include "clang/Lex/PPCallbacks.h"
21 #include "clang/Lex/Preprocessor.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;
35  DiagnosticsEngine &Diags;
36  DepCollectorPPCallbacks(DependencyCollector &L, SourceManager &SM,
37  DiagnosticsEngine &Diags)
38  : DepCollector(L), SM(SM), Diags(Diags) {}
39 
40  void FileChanged(SourceLocation Loc, FileChangeReason Reason,
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!
51  if (!File)
52  return;
53 
54  StringRef Filename =
55  llvm::sys::path::remove_leading_dotslash(File->getName());
56 
57  DepCollector.maybeAddDependency(Filename, /*FromModule*/false,
58  isSystem(FileType),
59  /*IsModuleFile*/false, /*IsMissing*/false);
60  }
61 
62  void FileSkipped(const FileEntryRef &SkippedFile, const Token &FilenameTok,
63  SrcMgr::CharacteristicKind FileType) override {
64  StringRef Filename =
65  llvm::sys::path::remove_leading_dotslash(SkippedFile.getName());
66  DepCollector.maybeAddDependency(Filename, /*FromModule=*/false,
67  /*IsSystem=*/isSystem(FileType),
68  /*IsModuleFile=*/false,
69  /*IsMissing=*/false);
70  }
71 
72  void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
73  StringRef FileName, bool IsAngled,
74  CharSourceRange FilenameRange, const FileEntry *File,
75  StringRef SearchPath, StringRef RelativePath,
76  const Module *Imported,
77  SrcMgr::CharacteristicKind FileType) override {
78  if (!File)
79  DepCollector.maybeAddDependency(FileName, /*FromModule*/false,
80  /*IsSystem*/false, /*IsModuleFile*/false,
81  /*IsMissing*/true);
82  // Files that actually exist are handled by FileChanged.
83  }
84 
85  void HasInclude(SourceLocation Loc, StringRef SpelledFilename, bool IsAngled,
87  SrcMgr::CharacteristicKind FileType) override {
88  if (!File)
89  return;
90  StringRef Filename =
91  llvm::sys::path::remove_leading_dotslash(File->getName());
92  DepCollector.maybeAddDependency(Filename, /*FromModule=*/false,
93  /*IsSystem=*/isSystem(FileType),
94  /*IsModuleFile=*/false,
95  /*IsMissing=*/false);
96  }
97 
98  void EndOfMainFile() override { DepCollector.finishedMainFile(Diags); }
99 };
100 
101 struct DepCollectorMMCallbacks : public ModuleMapCallbacks {
102  DependencyCollector &DepCollector;
103  DepCollectorMMCallbacks(DependencyCollector &DC) : DepCollector(DC) {}
104 
105  void moduleMapFileRead(SourceLocation Loc, const FileEntry &Entry,
106  bool IsSystem) override {
107  StringRef Filename = Entry.getName();
108  DepCollector.maybeAddDependency(Filename, /*FromModule*/false,
109  /*IsSystem*/IsSystem,
110  /*IsModuleFile*/false,
111  /*IsMissing*/false);
112  }
113 };
114 
115 struct DepCollectorASTListener : public ASTReaderListener {
116  DependencyCollector &DepCollector;
117  DepCollectorASTListener(DependencyCollector &L) : DepCollector(L) { }
118  bool needsInputFileVisitation() override { return true; }
119  bool needsSystemInputFileVisitation() override {
120  return DepCollector.needSystemDependencies();
121  }
122  void visitModuleFile(StringRef Filename,
123  serialization::ModuleKind Kind) override {
124  DepCollector.maybeAddDependency(Filename, /*FromModule*/true,
125  /*IsSystem*/false, /*IsModuleFile*/true,
126  /*IsMissing*/false);
127  }
128  bool visitInputFile(StringRef Filename, bool IsSystem,
129  bool IsOverridden, bool IsExplicitModule) override {
130  if (IsOverridden || IsExplicitModule)
131  return true;
132 
133  DepCollector.maybeAddDependency(Filename, /*FromModule*/true, IsSystem,
134  /*IsModuleFile*/false, /*IsMissing*/false);
135  return true;
136  }
137 };
138 } // end anonymous namespace
139 
141  bool FromModule, bool IsSystem,
142  bool IsModuleFile,
143  bool IsMissing) {
144  if (sawDependency(Filename, FromModule, IsSystem, IsModuleFile, IsMissing))
145  addDependency(Filename);
146 }
147 
148 bool DependencyCollector::addDependency(StringRef Filename) {
149  if (Seen.insert(Filename).second) {
150  Dependencies.push_back(std::string(Filename));
151  return true;
152  }
153  return false;
154 }
155 
156 static bool isSpecialFilename(StringRef Filename) {
157  return llvm::StringSwitch<bool>(Filename)
158  .Case("<built-in>", true)
159  .Case("<stdin>", true)
160  .Default(false);
161 }
162 
163 bool DependencyCollector::sawDependency(StringRef Filename, bool FromModule,
164  bool IsSystem, bool IsModuleFile,
165  bool IsMissing) {
166  return !isSpecialFilename(Filename) &&
167  (needSystemDependencies() || !IsSystem);
168 }
169 
172  PP.addPPCallbacks(std::make_unique<DepCollectorPPCallbacks>(
173  *this, PP.getSourceManager(), PP.getDiagnostics()));
175  std::make_unique<DepCollectorMMCallbacks>(*this));
176 }
178  R.addListener(std::make_unique<DepCollectorASTListener>(*this));
179 }
180 
182  const DependencyOutputOptions &Opts)
183  : OutputFile(Opts.OutputFile), Targets(Opts.Targets),
184  IncludeSystemHeaders(Opts.IncludeSystemHeaders),
185  PhonyTarget(Opts.UsePhonyTargets),
186  AddMissingHeaderDeps(Opts.AddMissingHeaderDeps), SeenMissingHeader(false),
187  IncludeModuleFiles(Opts.IncludeModuleFiles),
188  OutputFormat(Opts.OutputFormat), InputFileIndex(0) {
189  for (const auto &ExtraDep : Opts.ExtraDeps) {
190  if (addDependency(ExtraDep))
191  ++InputFileIndex;
192  }
193 }
194 
196  // Disable the "file not found" diagnostic if the -MG option was given.
197  if (AddMissingHeaderDeps)
199 
201 }
202 
203 bool DependencyFileGenerator::sawDependency(StringRef Filename, bool FromModule,
204  bool IsSystem, bool IsModuleFile,
205  bool IsMissing) {
206  if (IsMissing) {
207  // Handle the case of missing file from an inclusion directive.
208  if (AddMissingHeaderDeps)
209  return true;
210  SeenMissingHeader = true;
211  return false;
212  }
213  if (IsModuleFile && !IncludeModuleFiles)
214  return false;
215 
216  if (isSpecialFilename(Filename))
217  return false;
218 
219  if (IncludeSystemHeaders)
220  return true;
221 
222  return !IsSystem;
223 }
224 
226  outputDependencyFile(Diags);
227 }
228 
229 /// Print the filename, with escaping or quoting that accommodates the three
230 /// most likely tools that use dependency files: GNU Make, BSD Make, and
231 /// NMake/Jom.
232 ///
233 /// BSD Make is the simplest case: It does no escaping at all. This means
234 /// characters that are normally delimiters, i.e. space and # (the comment
235 /// character) simply aren't supported in filenames.
236 ///
237 /// GNU Make does allow space and # in filenames, but to avoid being treated
238 /// as a delimiter or comment, these must be escaped with a backslash. Because
239 /// backslash is itself the escape character, if a backslash appears in a
240 /// filename, it should be escaped as well. (As a special case, $ is escaped
241 /// as $$, which is the normal Make way to handle the $ character.)
242 /// For compatibility with BSD Make and historical practice, if GNU Make
243 /// un-escapes characters in a filename but doesn't find a match, it will
244 /// retry with the unmodified original string.
245 ///
246 /// GCC tries to accommodate both Make formats by escaping any space or #
247 /// characters in the original filename, but not escaping backslashes. The
248 /// apparent intent is so that filenames with backslashes will be handled
249 /// correctly by BSD Make, and by GNU Make in its fallback mode of using the
250 /// unmodified original string; filenames with # or space characters aren't
251 /// supported by BSD Make at all, but will be handled correctly by GNU Make
252 /// due to the escaping.
253 ///
254 /// A corner case that GCC gets only partly right is when the original filename
255 /// has a backslash immediately followed by space or #. GNU Make would expect
256 /// this backslash to be escaped; however GCC escapes the original backslash
257 /// only when followed by space, not #. It will therefore take a dependency
258 /// from a directive such as
259 /// #include "a\ b\#c.h"
260 /// and emit it as
261 /// a\\\ b\\#c.h
262 /// which GNU Make will interpret as
263 /// a\ b\
264 /// followed by a comment. Failing to find this file, it will fall back to the
265 /// original string, which probably doesn't exist either; in any case it won't
266 /// find
267 /// a\ b\#c.h
268 /// which is the actual filename specified by the include directive.
269 ///
270 /// Clang does what GCC does, rather than what GNU Make expects.
271 ///
272 /// NMake/Jom has a different set of scary characters, but wraps filespecs in
273 /// double-quotes to avoid misinterpreting them; see
274 /// https://msdn.microsoft.com/en-us/library/dd9y37ha.aspx for NMake info,
275 /// https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx
276 /// for Windows file-naming info.
277 static void PrintFilename(raw_ostream &OS, StringRef Filename,
278  DependencyOutputFormat OutputFormat) {
279  // Convert filename to platform native path
280  llvm::SmallString<256> NativePath;
281  llvm::sys::path::native(Filename.str(), NativePath);
282 
283  if (OutputFormat == DependencyOutputFormat::NMake) {
284  // Add quotes if needed. These are the characters listed as "special" to
285  // NMake, that are legal in a Windows filespec, and that could cause
286  // misinterpretation of the dependency string.
287  if (NativePath.find_first_of(" #${}^!") != StringRef::npos)
288  OS << '\"' << NativePath << '\"';
289  else
290  OS << NativePath;
291  return;
292  }
293  assert(OutputFormat == DependencyOutputFormat::Make);
294  for (unsigned i = 0, e = NativePath.size(); i != e; ++i) {
295  if (NativePath[i] == '#') // Handle '#' the broken gcc way.
296  OS << '\\';
297  else if (NativePath[i] == ' ') { // Handle space correctly.
298  OS << '\\';
299  unsigned j = i;
300  while (j > 0 && NativePath[--j] == '\\')
301  OS << '\\';
302  } else if (NativePath[i] == '$') // $ is escaped by $$.
303  OS << '$';
304  OS << NativePath[i];
305  }
306 }
307 
309  if (SeenMissingHeader) {
310  llvm::sys::fs::remove(OutputFile);
311  return;
312  }
313 
314  std::error_code EC;
315  llvm::raw_fd_ostream OS(OutputFile, EC, llvm::sys::fs::OF_Text);
316  if (EC) {
317  Diags.Report(diag::err_fe_error_opening) << OutputFile << EC.message();
318  return;
319  }
320 
322 }
323 
325  // Write out the dependency targets, trying to avoid overly long
326  // lines when possible. We try our best to emit exactly the same
327  // dependency file as GCC (4.2), assuming the included files are the
328  // same.
329  const unsigned MaxColumns = 75;
330  unsigned Columns = 0;
331 
332  for (StringRef Target : Targets) {
333  unsigned N = Target.size();
334  if (Columns == 0) {
335  Columns += N;
336  } else if (Columns + N + 2 > MaxColumns) {
337  Columns = N + 2;
338  OS << " \\\n ";
339  } else {
340  Columns += N + 1;
341  OS << ' ';
342  }
343  // Targets already quoted as needed.
344  OS << Target;
345  }
346 
347  OS << ':';
348  Columns += 1;
349 
350  // Now add each dependency in the order it was seen, but avoiding
351  // duplicates.
353  for (StringRef File : Files) {
354  // Start a new line if this would exceed the column limit. Make
355  // sure to leave space for a trailing " \" in case we need to
356  // break the line on the next iteration.
357  unsigned N = File.size();
358  if (Columns + (N + 1) + 2 > MaxColumns) {
359  OS << " \\\n ";
360  Columns = 2;
361  }
362  OS << ' ';
363  PrintFilename(OS, File, OutputFormat);
364  Columns += N + 1;
365  }
366  OS << '\n';
367 
368  // Create phony targets if requested.
369  if (PhonyTarget && !Files.empty()) {
370  unsigned Index = 0;
371  for (auto I = Files.begin(), E = Files.end(); I != E; ++I) {
372  if (Index++ == InputFileIndex)
373  continue;
374  OS << '\n';
375  PrintFilename(OS, *I, OutputFormat);
376  OS << ":\n";
377  }
378  }
379 }
DependencyFileGenerator(const DependencyOutputOptions &Opts)
Defines the clang::FileManager interface and associated types.
An interface for collecting the dependencies of a compilation.
Definition: Utils.h:76
Defines the SourceManager interface.
void finishedMainFile(DiagnosticsEngine &Diags) override
Called when the end of the main file is reached.
DiagnosticBuilder Report(SourceLocation Loc, unsigned DiagID)
Issue the message to the client.
Definition: Diagnostic.h:1330
A reference to a FileEntry that includes the name of the file as it was accessed by the FileManager&#39;s...
Definition: FileManager.h:131
const StringRef getName() const
Definition: FileManager.h:137
CharacteristicKind
Indicates whether a file or directory holds normal user code, system code, or system code which is im...
Definition: SourceManager.h:79
ModuleMap & getModuleMap()
Retrieve the module map.
Definition: HeaderSearch.h:665
This interface provides a way to observe the actions of the preprocessor as it does its thing...
Definition: PPCallbacks.h:35
bool sawDependency(StringRef Filename, bool FromModule, bool IsSystem, bool IsModuleFile, bool IsMissing) final override
Called when a new file is seen.
virtual bool needSystemDependencies()
Return true if system files should be passed to sawDependency().
Definition: Utils.h:95
Token - This structure provides full information about a lexed token.
Definition: Token.h:34
void outputDependencyFile(llvm::raw_ostream &OS)
Describes a module or submodule.
Definition: Module.h:87
void SetSuppressIncludeNotFoundError(bool Suppress)
Definition: Preprocessor.h:965
virtual void attachToASTReader(ASTReader &R)
HeaderSearch & getHeaderSearchInfo() const
Definition: Preprocessor.h:920
SourceLocation getExpansionLoc(SourceLocation Loc) const
Given a SourceLocation object Loc, return the expansion location referenced by the ID...
Concrete class used by the front-end to report problems and issues.
Definition: Diagnostic.h:153
void addModuleMapCallbacks(std::unique_ptr< ModuleMapCallbacks > Callback)
Add a module map callback.
Definition: ModuleMap.h:419
ModuleKind
Specifies the kind of module that has been loaded.
Definition: ModuleFile.h:41
StringRef Filename
Definition: Format.cpp:2018
virtual void maybeAddDependency(StringRef Filename, bool FromModule, bool IsSystem, bool IsModuleFile, bool IsMissing)
Add a dependency Filename if it has not been seen before and sawDependency() returns true...
ArrayRef< std::string > getDependencies() const
Definition: Utils.h:82
static bool isSpecialFilename(StringRef Filename)
Represents a character-granular source range.
bool addDependency(StringRef Filename)
Return true if the filename was added to the list of dependencies, false otherwise.
Defines the clang::Preprocessor interface.
ASTEdit remove(RangeSelector S)
Removes the source selected by S.
Definition: RewriteRule.cpp:93
A mechanism to observe the actions of the module map parser as it reads module map files...
Definition: ModuleMap.h:47
Record the location of an inclusion directive, such as an #include or #import statement.
#define SM(sm)
Definition: Cuda.cpp:62
SourceManager & getSourceManager() const
Definition: Preprocessor.h:919
#define false
Definition: stdbool.h:17
Kind
void addListener(std::unique_ptr< ASTReaderListener > L)
Add an AST callback listener.
Definition: ASTReader.h:1595
Encodes a location in the source.
StringRef getName() const
Definition: FileManager.h:103
Cached information about one file (either on disk or in the virtual file system). ...
Definition: FileManager.h:79
DependencyOutputOptions - Options for controlling the compiler dependency file generation.
std::vector< std::string > ExtraDeps
A list of filenames to be used as extra dependencies for every target.
An opaque identifier used by SourceManager which refers to a source file (MemoryBuffer) along with it...
Dataflow Directional Tag Classes.
virtual void finishedMainFile(DiagnosticsEngine &Diags)
Called when the end of the main file is reached.
Definition: Utils.h:92
Reads an AST files chain containing the contents of a translation unit.
Definition: ASTReader.h:340
void attachToPreprocessor(Preprocessor &PP) override
FileID getFileID(SourceLocation SpellingLoc) const
Return the FileID for a SourceLocation.
Abstract interface for callback invocations by the ASTReader.
Definition: ASTReader.h:112
virtual void attachToPreprocessor(Preprocessor &PP)
Defines the PPCallbacks interface.
DiagnosticsEngine & getDiagnostics() const
Definition: Preprocessor.h:912
Optional< FileEntryRef > getFileEntryRefForID(FileID FID) const
Returns the FileEntryRef for the provided FileID.
virtual bool sawDependency(StringRef Filename, bool FromModule, bool IsSystem, bool IsModuleFile, bool IsMissing)
Called when a new file is seen.
static void PrintFilename(raw_ostream &OS, StringRef Filename, DependencyOutputFormat OutputFormat)
Print the filename, with escaping or quoting that accommodates the three most likely tools that use d...
DependencyOutputFormat
DependencyOutputFormat - Format for the compiler dependency file.
bool isSystem(CharacteristicKind CK)
Determine whether a file / directory characteristic is for system code.
Definition: SourceManager.h:84
void addPPCallbacks(std::unique_ptr< PPCallbacks > C)
This class handles loading and caching of source files into memory.
Engages in a tight little dance with the lexer to efficiently preprocess tokens.
Definition: Preprocessor.h:128