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comparison clang/lib/Frontend/DependencyFile.cpp @ 150:1d019706d866

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LLVM10
author anatofuz
date Thu, 13 Feb 2020 15:10:13 +0900
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children 0572611fdcc8
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147:c2174574ed3a 150:1d019706d866
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 SourceManager &SM;
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,
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 Optional<FileEntryRef> File =
50 SM.getFileEntryRefForID(SM.getFileID(SM.getExpansionLoc(Loc)));
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,
86 Optional<FileEntryRef> File,
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
140 void DependencyCollector::maybeAddDependency(StringRef Filename, bool FromModule,
141 bool IsSystem, bool IsModuleFile,
142 bool IsMissing) {
143 if (sawDependency(Filename, FromModule, IsSystem, IsModuleFile, IsMissing))
144 addDependency(Filename);
145 }
146
147 bool DependencyCollector::addDependency(StringRef Filename) {
148 if (Seen.insert(Filename).second) {
149 Dependencies.push_back(std::string(Filename));
150 return true;
151 }
152 return false;
153 }
154
155 static bool isSpecialFilename(StringRef Filename) {
156 return llvm::StringSwitch<bool>(Filename)
157 .Case("<built-in>", true)
158 .Case("<stdin>", true)
159 .Default(false);
160 }
161
162 bool DependencyCollector::sawDependency(StringRef Filename, bool FromModule,
163 bool IsSystem, bool IsModuleFile,
164 bool IsMissing) {
165 return !isSpecialFilename(Filename) &&
166 (needSystemDependencies() || !IsSystem);
167 }
168
169 DependencyCollector::~DependencyCollector() { }
170 void DependencyCollector::attachToPreprocessor(Preprocessor &PP) {
171 PP.addPPCallbacks(std::make_unique<DepCollectorPPCallbacks>(
172 *this, PP.getSourceManager(), PP.getDiagnostics()));
173 PP.getHeaderSearchInfo().getModuleMap().addModuleMapCallbacks(
174 std::make_unique<DepCollectorMMCallbacks>(*this));
175 }
176 void DependencyCollector::attachToASTReader(ASTReader &R) {
177 R.addListener(std::make_unique<DepCollectorASTListener>(*this));
178 }
179
180 DependencyFileGenerator::DependencyFileGenerator(
181 const DependencyOutputOptions &Opts)
182 : OutputFile(Opts.OutputFile), Targets(Opts.Targets),
183 IncludeSystemHeaders(Opts.IncludeSystemHeaders),
184 PhonyTarget(Opts.UsePhonyTargets),
185 AddMissingHeaderDeps(Opts.AddMissingHeaderDeps), SeenMissingHeader(false),
186 IncludeModuleFiles(Opts.IncludeModuleFiles),
187 OutputFormat(Opts.OutputFormat), InputFileIndex(0) {
188 for (const auto &ExtraDep : Opts.ExtraDeps) {
189 if (addDependency(ExtraDep))
190 ++InputFileIndex;
191 }
192 }
193
194 void DependencyFileGenerator::attachToPreprocessor(Preprocessor &PP) {
195 // Disable the "file not found" diagnostic if the -MG option was given.
196 if (AddMissingHeaderDeps)
197 PP.SetSuppressIncludeNotFoundError(true);
198
199 DependencyCollector::attachToPreprocessor(PP);
200 }
201
202 bool DependencyFileGenerator::sawDependency(StringRef Filename, bool FromModule,
203 bool IsSystem, bool IsModuleFile,
204 bool IsMissing) {
205 if (IsMissing) {
206 // Handle the case of missing file from an inclusion directive.
207 if (AddMissingHeaderDeps)
208 return true;
209 SeenMissingHeader = true;
210 return false;
211 }
212 if (IsModuleFile && !IncludeModuleFiles)
213 return false;
214
215 if (isSpecialFilename(Filename))
216 return false;
217
218 if (IncludeSystemHeaders)
219 return true;
220
221 return !IsSystem;
222 }
223
224 void DependencyFileGenerator::finishedMainFile(DiagnosticsEngine &Diags) {
225 outputDependencyFile(Diags);
226 }
227
228 /// Print the filename, with escaping or quoting that accommodates the three
229 /// most likely tools that use dependency files: GNU Make, BSD Make, and
230 /// NMake/Jom.
231 ///
232 /// BSD Make is the simplest case: It does no escaping at all. This means
233 /// characters that are normally delimiters, i.e. space and # (the comment
234 /// character) simply aren't supported in filenames.
235 ///
236 /// GNU Make does allow space and # in filenames, but to avoid being treated
237 /// as a delimiter or comment, these must be escaped with a backslash. Because
238 /// backslash is itself the escape character, if a backslash appears in a
239 /// filename, it should be escaped as well. (As a special case, $ is escaped
240 /// as $$, which is the normal Make way to handle the $ character.)
241 /// For compatibility with BSD Make and historical practice, if GNU Make
242 /// un-escapes characters in a filename but doesn't find a match, it will
243 /// retry with the unmodified original string.
244 ///
245 /// GCC tries to accommodate both Make formats by escaping any space or #
246 /// characters in the original filename, but not escaping backslashes. The
247 /// apparent intent is so that filenames with backslashes will be handled
248 /// correctly by BSD Make, and by GNU Make in its fallback mode of using the
249 /// unmodified original string; filenames with # or space characters aren't
250 /// supported by BSD Make at all, but will be handled correctly by GNU Make
251 /// due to the escaping.
252 ///
253 /// A corner case that GCC gets only partly right is when the original filename
254 /// has a backslash immediately followed by space or #. GNU Make would expect
255 /// this backslash to be escaped; however GCC escapes the original backslash
256 /// only when followed by space, not #. It will therefore take a dependency
257 /// from a directive such as
258 /// #include "a\ b\#c.h"
259 /// and emit it as
260 /// a\\\ b\\#c.h
261 /// which GNU Make will interpret as
262 /// a\ b\
263 /// followed by a comment. Failing to find this file, it will fall back to the
264 /// original string, which probably doesn't exist either; in any case it won't
265 /// find
266 /// a\ b\#c.h
267 /// which is the actual filename specified by the include directive.
268 ///
269 /// Clang does what GCC does, rather than what GNU Make expects.
270 ///
271 /// NMake/Jom has a different set of scary characters, but wraps filespecs in
272 /// double-quotes to avoid misinterpreting them; see
273 /// https://msdn.microsoft.com/en-us/library/dd9y37ha.aspx for NMake info,
274 /// https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx
275 /// for Windows file-naming info.
276 static void PrintFilename(raw_ostream &OS, StringRef Filename,
277 DependencyOutputFormat OutputFormat) {
278 // Convert filename to platform native path
279 llvm::SmallString<256> NativePath;
280 llvm::sys::path::native(Filename.str(), NativePath);
281
282 if (OutputFormat == DependencyOutputFormat::NMake) {
283 // Add quotes if needed. These are the characters listed as "special" to
284 // NMake, that are legal in a Windows filespec, and that could cause
285 // misinterpretation of the dependency string.
286 if (NativePath.find_first_of(" #${}^!") != StringRef::npos)
287 OS << '\"' << NativePath << '\"';
288 else
289 OS << NativePath;
290 return;
291 }
292 assert(OutputFormat == DependencyOutputFormat::Make);
293 for (unsigned i = 0, e = NativePath.size(); i != e; ++i) {
294 if (NativePath[i] == '#') // Handle '#' the broken gcc way.
295 OS << '\\';
296 else if (NativePath[i] == ' ') { // Handle space correctly.
297 OS << '\\';
298 unsigned j = i;
299 while (j > 0 && NativePath[--j] == '\\')
300 OS << '\\';
301 } else if (NativePath[i] == '$') // $ is escaped by $$.
302 OS << '$';
303 OS << NativePath[i];
304 }
305 }
306
307 void DependencyFileGenerator::outputDependencyFile(DiagnosticsEngine &Diags) {
308 if (SeenMissingHeader) {
309 llvm::sys::fs::remove(OutputFile);
310 return;
311 }
312
313 std::error_code EC;
314 llvm::raw_fd_ostream OS(OutputFile, EC, llvm::sys::fs::OF_Text);
315 if (EC) {
316 Diags.Report(diag::err_fe_error_opening) << OutputFile << EC.message();
317 return;
318 }
319
320 outputDependencyFile(OS);
321 }
322
323 void DependencyFileGenerator::outputDependencyFile(llvm::raw_ostream &OS) {
324 // Write out the dependency targets, trying to avoid overly long
325 // lines when possible. We try our best to emit exactly the same
326 // dependency file as GCC (4.2), assuming the included files are the
327 // same.
328 const unsigned MaxColumns = 75;
329 unsigned Columns = 0;
330
331 for (StringRef Target : Targets) {
332 unsigned N = Target.size();
333 if (Columns == 0) {
334 Columns += N;
335 } else if (Columns + N + 2 > MaxColumns) {
336 Columns = N + 2;
337 OS << " \\\n ";
338 } else {
339 Columns += N + 1;
340 OS << ' ';
341 }
342 // Targets already quoted as needed.
343 OS << Target;
344 }
345
346 OS << ':';
347 Columns += 1;
348
349 // Now add each dependency in the order it was seen, but avoiding
350 // duplicates.
351 ArrayRef<std::string> Files = getDependencies();
352 for (StringRef File : Files) {
353 // Start a new line if this would exceed the column limit. Make
354 // sure to leave space for a trailing " \" in case we need to
355 // break the line on the next iteration.
356 unsigned N = File.size();
357 if (Columns + (N + 1) + 2 > MaxColumns) {
358 OS << " \\\n ";
359 Columns = 2;
360 }
361 OS << ' ';
362 PrintFilename(OS, File, OutputFormat);
363 Columns += N + 1;
364 }
365 OS << '\n';
366
367 // Create phony targets if requested.
368 if (PhonyTarget && !Files.empty()) {
369 unsigned Index = 0;
370 for (auto I = Files.begin(), E = Files.end(); I != E; ++I) {
371 if (Index++ == InputFileIndex)
372 continue;
373 OS << '\n';
374 PrintFilename(OS, *I, OutputFormat);
375 OS << ":\n";
376 }
377 }
378 }