1 //===-- HeaderIncludeGen.cpp - Generate Header Includes -------------------===//
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 #include "clang/Frontend/DependencyOutputOptions.h"
10 #include "clang/Frontend/Utils.h"
11 #include "clang/Basic/SourceManager.h"
12 #include "clang/Frontend/FrontendDiagnostic.h"
13 #include "clang/Lex/Preprocessor.h"
14 #include "llvm/ADT/SmallString.h"
15 #include "llvm/Support/JSON.h"
16 #include "llvm/Support/raw_ostream.h"
17 using namespace clang;
18
19 namespace {
20 class HeaderIncludesCallback : public PPCallbacks {
21 SourceManager &SM;
22 raw_ostream *OutputFile;
23 const DependencyOutputOptions &DepOpts;
24 unsigned CurrentIncludeDepth;
25 bool HasProcessedPredefines;
26 bool OwnsOutputFile;
27 bool ShowAllHeaders;
28 bool ShowDepth;
29 bool MSStyle;
30
31 public:
HeaderIncludesCallback(const Preprocessor * PP,bool ShowAllHeaders_,raw_ostream * OutputFile_,const DependencyOutputOptions & DepOpts,bool OwnsOutputFile_,bool ShowDepth_,bool MSStyle_)32 HeaderIncludesCallback(const Preprocessor *PP, bool ShowAllHeaders_,
33 raw_ostream *OutputFile_,
34 const DependencyOutputOptions &DepOpts,
35 bool OwnsOutputFile_, bool ShowDepth_, bool MSStyle_)
36 : SM(PP->getSourceManager()), OutputFile(OutputFile_), DepOpts(DepOpts),
37 CurrentIncludeDepth(0), HasProcessedPredefines(false),
38 OwnsOutputFile(OwnsOutputFile_), ShowAllHeaders(ShowAllHeaders_),
39 ShowDepth(ShowDepth_), MSStyle(MSStyle_) {}
40
~HeaderIncludesCallback()41 ~HeaderIncludesCallback() override {
42 if (OwnsOutputFile)
43 delete OutputFile;
44 }
45
46 void FileChanged(SourceLocation Loc, FileChangeReason Reason,
47 SrcMgr::CharacteristicKind FileType,
48 FileID PrevFID) override;
49
50 void FileSkipped(const FileEntryRef &SkippedFile, const Token &FilenameTok,
51 SrcMgr::CharacteristicKind FileType) override;
52 };
53
54 /// A callback for emitting header usage information to a file in JSON. Each
55 /// line in the file is a JSON object that includes the source file name and
56 /// the list of headers directly or indirectly included from it. For example:
57 ///
58 /// {"source":"/tmp/foo.c",
59 /// "includes":["/usr/include/stdio.h", "/usr/include/stdlib.h"]}
60 ///
61 /// To reduce the amount of data written to the file, we only record system
62 /// headers that are directly included from a file that isn't in the system
63 /// directory.
64 class HeaderIncludesJSONCallback : public PPCallbacks {
65 SourceManager &SM;
66 raw_ostream *OutputFile;
67 bool OwnsOutputFile;
68 SmallVector<std::string, 16> IncludedHeaders;
69
70 public:
HeaderIncludesJSONCallback(const Preprocessor * PP,raw_ostream * OutputFile_,bool OwnsOutputFile_)71 HeaderIncludesJSONCallback(const Preprocessor *PP, raw_ostream *OutputFile_,
72 bool OwnsOutputFile_)
73 : SM(PP->getSourceManager()), OutputFile(OutputFile_),
74 OwnsOutputFile(OwnsOutputFile_) {}
75
~HeaderIncludesJSONCallback()76 ~HeaderIncludesJSONCallback() override {
77 if (OwnsOutputFile)
78 delete OutputFile;
79 }
80
81 void EndOfMainFile() override;
82
83 void FileChanged(SourceLocation Loc, FileChangeReason Reason,
84 SrcMgr::CharacteristicKind FileType,
85 FileID PrevFID) override;
86
87 void FileSkipped(const FileEntryRef &SkippedFile, const Token &FilenameTok,
88 SrcMgr::CharacteristicKind FileType) override;
89 };
90 }
91
PrintHeaderInfo(raw_ostream * OutputFile,StringRef Filename,bool ShowDepth,unsigned CurrentIncludeDepth,bool MSStyle)92 static void PrintHeaderInfo(raw_ostream *OutputFile, StringRef Filename,
93 bool ShowDepth, unsigned CurrentIncludeDepth,
94 bool MSStyle) {
95 // Write to a temporary string to avoid unnecessary flushing on errs().
96 SmallString<512> Pathname(Filename);
97 if (!MSStyle)
98 Lexer::Stringify(Pathname);
99
100 SmallString<256> Msg;
101 if (MSStyle)
102 Msg += "Note: including file:";
103
104 if (ShowDepth) {
105 // The main source file is at depth 1, so skip one dot.
106 for (unsigned i = 1; i != CurrentIncludeDepth; ++i)
107 Msg += MSStyle ? ' ' : '.';
108
109 if (!MSStyle)
110 Msg += ' ';
111 }
112 Msg += Pathname;
113 Msg += '\n';
114
115 *OutputFile << Msg;
116 OutputFile->flush();
117 }
118
AttachHeaderIncludeGen(Preprocessor & PP,const DependencyOutputOptions & DepOpts,bool ShowAllHeaders,StringRef OutputPath,bool ShowDepth,bool MSStyle)119 void clang::AttachHeaderIncludeGen(Preprocessor &PP,
120 const DependencyOutputOptions &DepOpts,
121 bool ShowAllHeaders, StringRef OutputPath,
122 bool ShowDepth, bool MSStyle) {
123 raw_ostream *OutputFile = &llvm::errs();
124 bool OwnsOutputFile = false;
125
126 // Choose output stream, when printing in cl.exe /showIncludes style.
127 if (MSStyle) {
128 switch (DepOpts.ShowIncludesDest) {
129 default:
130 llvm_unreachable("Invalid destination for /showIncludes output!");
131 case ShowIncludesDestination::Stderr:
132 OutputFile = &llvm::errs();
133 break;
134 case ShowIncludesDestination::Stdout:
135 OutputFile = &llvm::outs();
136 break;
137 }
138 }
139
140 // Open the output file, if used.
141 if (!OutputPath.empty()) {
142 std::error_code EC;
143 llvm::raw_fd_ostream *OS = new llvm::raw_fd_ostream(
144 OutputPath.str(), EC,
145 llvm::sys::fs::OF_Append | llvm::sys::fs::OF_TextWithCRLF);
146 if (EC) {
147 PP.getDiagnostics().Report(clang::diag::warn_fe_cc_print_header_failure)
148 << EC.message();
149 delete OS;
150 } else {
151 OS->SetUnbuffered();
152 OutputFile = OS;
153 OwnsOutputFile = true;
154 }
155 }
156
157 switch (DepOpts.HeaderIncludeFormat) {
158 case HIFMT_None:
159 llvm_unreachable("unexpected header format kind");
160 case HIFMT_Textual: {
161 assert(DepOpts.HeaderIncludeFiltering == HIFIL_None &&
162 "header filtering is currently always disabled when output format is"
163 "textual");
164 // Print header info for extra headers, pretending they were discovered by
165 // the regular preprocessor. The primary use case is to support proper
166 // generation of Make / Ninja file dependencies for implicit includes, such
167 // as sanitizer ignorelists. It's only important for cl.exe compatibility,
168 // the GNU way to generate rules is -M / -MM / -MD / -MMD.
169 for (const auto &Header : DepOpts.ExtraDeps)
170 PrintHeaderInfo(OutputFile, Header.first, ShowDepth, 2, MSStyle);
171 PP.addPPCallbacks(std::make_unique<HeaderIncludesCallback>(
172 &PP, ShowAllHeaders, OutputFile, DepOpts, OwnsOutputFile, ShowDepth,
173 MSStyle));
174 break;
175 }
176 case HIFMT_JSON: {
177 assert(DepOpts.HeaderIncludeFiltering == HIFIL_Only_Direct_System &&
178 "only-direct-system is the only option for filtering");
179 PP.addPPCallbacks(std::make_unique<HeaderIncludesJSONCallback>(
180 &PP, OutputFile, OwnsOutputFile));
181 break;
182 }
183 }
184 }
185
FileChanged(SourceLocation Loc,FileChangeReason Reason,SrcMgr::CharacteristicKind NewFileType,FileID PrevFID)186 void HeaderIncludesCallback::FileChanged(SourceLocation Loc,
187 FileChangeReason Reason,
188 SrcMgr::CharacteristicKind NewFileType,
189 FileID PrevFID) {
190 // Unless we are exiting a #include, make sure to skip ahead to the line the
191 // #include directive was at.
192 PresumedLoc UserLoc = SM.getPresumedLoc(Loc);
193 if (UserLoc.isInvalid())
194 return;
195
196 // Adjust the current include depth.
197 if (Reason == PPCallbacks::EnterFile) {
198 ++CurrentIncludeDepth;
199 } else if (Reason == PPCallbacks::ExitFile) {
200 if (CurrentIncludeDepth)
201 --CurrentIncludeDepth;
202
203 // We track when we are done with the predefines by watching for the first
204 // place where we drop back to a nesting depth of 1.
205 if (CurrentIncludeDepth == 1 && !HasProcessedPredefines) {
206 if (!DepOpts.ShowIncludesPretendHeader.empty()) {
207 PrintHeaderInfo(OutputFile, DepOpts.ShowIncludesPretendHeader,
208 ShowDepth, 2, MSStyle);
209 }
210 HasProcessedPredefines = true;
211 }
212
213 return;
214 } else
215 return;
216
217 // Show the header if we are (a) past the predefines, or (b) showing all
218 // headers and in the predefines at a depth past the initial file and command
219 // line buffers.
220 bool ShowHeader = (HasProcessedPredefines ||
221 (ShowAllHeaders && CurrentIncludeDepth > 2));
222 unsigned IncludeDepth = CurrentIncludeDepth;
223 if (!HasProcessedPredefines)
224 --IncludeDepth; // Ignore indent from <built-in>.
225 else if (!DepOpts.ShowIncludesPretendHeader.empty())
226 ++IncludeDepth; // Pretend inclusion by ShowIncludesPretendHeader.
227
228 if (!DepOpts.IncludeSystemHeaders && isSystem(NewFileType))
229 ShowHeader = false;
230
231 // Dump the header include information we are past the predefines buffer or
232 // are showing all headers and this isn't the magic implicit <command line>
233 // header.
234 // FIXME: Identify headers in a more robust way than comparing their name to
235 // "<command line>" and "<built-in>" in a bunch of places.
236 if (ShowHeader && Reason == PPCallbacks::EnterFile &&
237 UserLoc.getFilename() != StringRef("<command line>")) {
238 PrintHeaderInfo(OutputFile, UserLoc.getFilename(), ShowDepth, IncludeDepth,
239 MSStyle);
240 }
241 }
242
FileSkipped(const FileEntryRef & SkippedFile,const Token & FilenameTok,SrcMgr::CharacteristicKind FileType)243 void HeaderIncludesCallback::FileSkipped(const FileEntryRef &SkippedFile, const
244 Token &FilenameTok,
245 SrcMgr::CharacteristicKind FileType) {
246 if (!DepOpts.ShowSkippedHeaderIncludes)
247 return;
248
249 if (!DepOpts.IncludeSystemHeaders && isSystem(FileType))
250 return;
251
252 PrintHeaderInfo(OutputFile, SkippedFile.getName(), ShowDepth,
253 CurrentIncludeDepth + 1, MSStyle);
254 }
255
EndOfMainFile()256 void HeaderIncludesJSONCallback::EndOfMainFile() {
257 const FileEntry *FE = SM.getFileEntryForID(SM.getMainFileID());
258 SmallString<256> MainFile(FE->getName());
259 SM.getFileManager().makeAbsolutePath(MainFile);
260
261 std::string Str;
262 llvm::raw_string_ostream OS(Str);
263 llvm::json::OStream JOS(OS);
264 JOS.object([&] {
265 JOS.attribute("source", MainFile.c_str());
266 JOS.attributeArray("includes", [&] {
267 llvm::StringSet<> SeenHeaders;
268 for (const std::string &H : IncludedHeaders)
269 if (SeenHeaders.insert(H).second)
270 JOS.value(H);
271 });
272 });
273 OS << "\n";
274
275 if (OutputFile->get_kind() == raw_ostream::OStreamKind::OK_FDStream) {
276 llvm::raw_fd_ostream *FDS = static_cast<llvm::raw_fd_ostream *>(OutputFile);
277 if (auto L = FDS->lock())
278 *OutputFile << Str;
279 } else
280 *OutputFile << Str;
281 }
282
283 /// Determine whether the header file should be recorded. The header file should
284 /// be recorded only if the header file is a system header and the current file
285 /// isn't a system header.
shouldRecordNewFile(SrcMgr::CharacteristicKind NewFileType,SourceLocation PrevLoc,SourceManager & SM)286 static bool shouldRecordNewFile(SrcMgr::CharacteristicKind NewFileType,
287 SourceLocation PrevLoc, SourceManager &SM) {
288 return SrcMgr::isSystem(NewFileType) && !SM.isInSystemHeader(PrevLoc);
289 }
290
FileChanged(SourceLocation Loc,FileChangeReason Reason,SrcMgr::CharacteristicKind NewFileType,FileID PrevFID)291 void HeaderIncludesJSONCallback::FileChanged(
292 SourceLocation Loc, FileChangeReason Reason,
293 SrcMgr::CharacteristicKind NewFileType, FileID PrevFID) {
294 if (PrevFID.isInvalid() ||
295 !shouldRecordNewFile(NewFileType, SM.getLocForStartOfFile(PrevFID), SM))
296 return;
297
298 // Unless we are exiting a #include, make sure to skip ahead to the line the
299 // #include directive was at.
300 PresumedLoc UserLoc = SM.getPresumedLoc(Loc);
301 if (UserLoc.isInvalid())
302 return;
303
304 if (Reason == PPCallbacks::EnterFile &&
305 UserLoc.getFilename() != StringRef("<command line>"))
306 IncludedHeaders.push_back(UserLoc.getFilename());
307 }
308
FileSkipped(const FileEntryRef & SkippedFile,const Token & FilenameTok,SrcMgr::CharacteristicKind FileType)309 void HeaderIncludesJSONCallback::FileSkipped(
310 const FileEntryRef &SkippedFile, const Token &FilenameTok,
311 SrcMgr::CharacteristicKind FileType) {
312 if (!shouldRecordNewFile(FileType, FilenameTok.getLocation(), SM))
313 return;
314
315 IncludedHeaders.push_back(SkippedFile.getName().str());
316 }
317