xref: /llvm-project/clang-tools-extra/clang-doc/tool/ClangDocMain.cpp (revision b43cfa7e45dfd252dcf8de6a753558e698a216d2)
1 //===-- ClangDocMain.cpp - ClangDoc -----------------------------*- C++ -*-===//
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 tool for generating C and C++ documentation from source code
10 // and comments. Generally, it runs a LibTooling FrontendAction on source files,
11 // mapping each declaration in those files to its USR and serializing relevant
12 // information into LLVM bitcode. It then runs a pass over the collected
13 // declaration information, reducing by USR. There is an option to dump this
14 // intermediate result to bitcode. Finally, it hands the reduced information
15 // off to a generator, which does the final parsing from the intermediate
16 // representation to the desired output format.
17 //
18 //===----------------------------------------------------------------------===//
19 
20 #include "BitcodeReader.h"
21 #include "BitcodeWriter.h"
22 #include "ClangDoc.h"
23 #include "Generators.h"
24 #include "Representation.h"
25 #include "clang/AST/AST.h"
26 #include "clang/AST/Decl.h"
27 #include "clang/ASTMatchers/ASTMatchFinder.h"
28 #include "clang/ASTMatchers/ASTMatchersInternal.h"
29 #include "clang/Driver/Options.h"
30 #include "clang/Frontend/FrontendActions.h"
31 #include "clang/Tooling/AllTUsExecution.h"
32 #include "clang/Tooling/CommonOptionsParser.h"
33 #include "clang/Tooling/Execution.h"
34 #include "clang/Tooling/Tooling.h"
35 #include "llvm/ADT/APFloat.h"
36 #include "llvm/Support/CommandLine.h"
37 #include "llvm/Support/Error.h"
38 #include "llvm/Support/FileSystem.h"
39 #include "llvm/Support/Mutex.h"
40 #include "llvm/Support/Path.h"
41 #include "llvm/Support/Process.h"
42 #include "llvm/Support/Signals.h"
43 #include "llvm/Support/ThreadPool.h"
44 #include "llvm/Support/raw_ostream.h"
45 #include <atomic>
46 #include <mutex>
47 #include <string>
48 
49 using namespace clang::ast_matchers;
50 using namespace clang::tooling;
51 using namespace clang;
52 
53 static llvm::cl::extrahelp CommonHelp(CommonOptionsParser::HelpMessage);
54 static llvm::cl::OptionCategory ClangDocCategory("clang-doc options");
55 
56 static llvm::cl::opt<std::string>
57     ProjectName("project-name", llvm::cl::desc("Name of project."),
58                 llvm::cl::cat(ClangDocCategory));
59 
60 static llvm::cl::opt<bool> IgnoreMappingFailures(
61     "ignore-map-errors",
62     llvm::cl::desc("Continue if files are not mapped correctly."),
63     llvm::cl::init(true), llvm::cl::cat(ClangDocCategory));
64 
65 static llvm::cl::opt<std::string>
66     OutDirectory("output",
67                  llvm::cl::desc("Directory for outputting generated files."),
68                  llvm::cl::init("docs"), llvm::cl::cat(ClangDocCategory));
69 
70 static llvm::cl::opt<bool>
71     PublicOnly("public", llvm::cl::desc("Document only public declarations."),
72                llvm::cl::init(false), llvm::cl::cat(ClangDocCategory));
73 
74 static llvm::cl::opt<bool> DoxygenOnly(
75     "doxygen",
76     llvm::cl::desc("Use only doxygen-style comments to generate docs."),
77     llvm::cl::init(false), llvm::cl::cat(ClangDocCategory));
78 
79 static llvm::cl::list<std::string> UserStylesheets(
80     "stylesheets", llvm::cl::CommaSeparated,
81     llvm::cl::desc("CSS stylesheets to extend the default styles."),
82     llvm::cl::cat(ClangDocCategory));
83 
84 static llvm::cl::opt<std::string> UserAssetPath(
85     "asset",
86     llvm::cl::desc("User supplied asset path to "
87                    "override the default css and js files for html output"),
88     llvm::cl::cat(ClangDocCategory));
89 
90 static llvm::cl::opt<std::string> SourceRoot("source-root", llvm::cl::desc(R"(
91 Directory where processed files are stored.
92 Links to definition locations will only be
93 generated if the file is in this dir.)"),
94                                              llvm::cl::cat(ClangDocCategory));
95 
96 static llvm::cl::opt<std::string>
97     RepositoryUrl("repository", llvm::cl::desc(R"(
98 URL of repository that hosts code.
99 Used for links to definition locations.)"),
100                   llvm::cl::cat(ClangDocCategory));
101 
102 enum OutputFormatTy {
103   md,
104   yaml,
105   html,
106 };
107 
108 static llvm::cl::opt<OutputFormatTy>
109     FormatEnum("format", llvm::cl::desc("Format for outputted docs."),
110                llvm::cl::values(clEnumValN(OutputFormatTy::yaml, "yaml",
111                                            "Documentation in YAML format."),
112                                 clEnumValN(OutputFormatTy::md, "md",
113                                            "Documentation in MD format."),
114                                 clEnumValN(OutputFormatTy::html, "html",
115                                            "Documentation in HTML format.")),
116                llvm::cl::init(OutputFormatTy::yaml),
117                llvm::cl::cat(ClangDocCategory));
118 
119 std::string getFormatString() {
120   switch (FormatEnum) {
121   case OutputFormatTy::yaml:
122     return "yaml";
123   case OutputFormatTy::md:
124     return "md";
125   case OutputFormatTy::html:
126     return "html";
127   }
128   llvm_unreachable("Unknown OutputFormatTy");
129 }
130 
131 // This function isn't referenced outside its translation unit, but it
132 // can't use the "static" keyword because its address is used for
133 // GetMainExecutable (since some platforms don't support taking the
134 // address of main, and some platforms can't implement GetMainExecutable
135 // without being given the address of a function in the main executable).
136 std::string getExecutablePath(const char *Argv0, void *MainAddr) {
137   return llvm::sys::fs::getMainExecutable(Argv0, MainAddr);
138 }
139 
140 llvm::Error getAssetFiles(clang::doc::ClangDocContext &CDCtx) {
141   using DirIt = llvm::sys::fs::directory_iterator;
142   std::error_code FileErr;
143   llvm::SmallString<128> FilePath(UserAssetPath);
144   for (DirIt DirStart = DirIt(UserAssetPath, FileErr),
145                    DirEnd;
146        !FileErr && DirStart != DirEnd; DirStart.increment(FileErr)) {
147     FilePath = DirStart->path();
148     if (llvm::sys::fs::is_regular_file(FilePath)) {
149       if (llvm::sys::path::extension(FilePath) == ".css")
150         CDCtx.UserStylesheets.insert(CDCtx.UserStylesheets.begin(),
151                                      std::string(FilePath));
152       else if (llvm::sys::path::extension(FilePath) == ".js")
153         CDCtx.JsScripts.emplace_back(FilePath.str());
154     }
155   }
156   if (FileErr)
157     return llvm::createFileError(FilePath, FileErr);
158   return llvm::Error::success();
159 }
160 
161 llvm::Error getDefaultAssetFiles(const char *Argv0,
162                                  clang::doc::ClangDocContext &CDCtx) {
163   void *MainAddr = (void *)(intptr_t)getExecutablePath;
164   std::string ClangDocPath = getExecutablePath(Argv0, MainAddr);
165   llvm::SmallString<128> NativeClangDocPath;
166   llvm::sys::path::native(ClangDocPath, NativeClangDocPath);
167 
168   llvm::SmallString<128> AssetsPath;
169   AssetsPath = llvm::sys::path::parent_path(NativeClangDocPath);
170   llvm::sys::path::append(AssetsPath, "..", "share", "clang-doc");
171   llvm::SmallString<128> DefaultStylesheet;
172   llvm::sys::path::native(AssetsPath, DefaultStylesheet);
173   llvm::sys::path::append(DefaultStylesheet,
174                           "clang-doc-default-stylesheet.css");
175   llvm::SmallString<128> IndexJS;
176   llvm::sys::path::native(AssetsPath, IndexJS);
177   llvm::sys::path::append(IndexJS, "index.js");
178 
179   if (!llvm::sys::fs::is_regular_file(IndexJS))
180     return llvm::createStringError(llvm::inconvertibleErrorCode(),
181                                    "default index.js file missing at " +
182                                        IndexJS + "\n");
183 
184   if (!llvm::sys::fs::is_regular_file(DefaultStylesheet))
185     return llvm::createStringError(
186         llvm::inconvertibleErrorCode(),
187         "default clang-doc-default-stylesheet.css file missing at " +
188             DefaultStylesheet + "\n");
189 
190   CDCtx.UserStylesheets.insert(CDCtx.UserStylesheets.begin(),
191                                std::string(DefaultStylesheet));
192   CDCtx.JsScripts.emplace_back(IndexJS.str());
193 
194   return llvm::Error::success();
195 }
196 
197 llvm::Error getHtmlAssetFiles(const char *Argv0,
198                               clang::doc::ClangDocContext &CDCtx) {
199   if (!UserAssetPath.empty() &&
200       !llvm::sys::fs::is_directory(std::string(UserAssetPath)))
201     llvm::outs() << "Asset path supply is not a directory: " << UserAssetPath
202                  << " falling back to default\n";
203   if (llvm::sys::fs::is_directory(std::string(UserAssetPath)))
204     return getAssetFiles(CDCtx);
205   return getDefaultAssetFiles(Argv0, CDCtx);
206 }
207 
208 /// Make the output of clang-doc deterministic by sorting the children of
209 /// namespaces and records.
210 void sortUsrToInfo(llvm::StringMap<std::unique_ptr<doc::Info>> &USRToInfo) {
211   for (auto &I : USRToInfo) {
212     auto &Info = I.second;
213     if (Info->IT == doc::InfoType::IT_namespace) {
214       auto *Namespace = static_cast<clang::doc::NamespaceInfo *>(Info.get());
215       Namespace->Children.sort();
216     }
217     if (Info->IT == doc::InfoType::IT_record) {
218       auto *Record = static_cast<clang::doc::RecordInfo *>(Info.get());
219       Record->Children.sort();
220     }
221   }
222 }
223 
224 int main(int argc, const char **argv) {
225   llvm::sys::PrintStackTraceOnErrorSignal(argv[0]);
226   std::error_code OK;
227 
228   const char *Overview =
229       R"(Generates documentation from source code and comments.
230 
231 Example usage for files without flags (default):
232 
233   $ clang-doc File1.cpp File2.cpp ... FileN.cpp
234 
235 Example usage for a project using a compile commands database:
236 
237   $ clang-doc --executor=all-TUs compile_commands.json
238 )";
239 
240   auto Executor = clang::tooling::createExecutorFromCommandLineArgs(
241       argc, argv, ClangDocCategory, Overview);
242 
243   if (!Executor) {
244     llvm::errs() << toString(Executor.takeError()) << "\n";
245     return 1;
246   }
247 
248   // Fail early if an invalid format was provided.
249   std::string Format = getFormatString();
250   llvm::outs() << "Emiting docs in " << Format << " format.\n";
251   auto G = doc::findGeneratorByName(Format);
252   if (!G) {
253     llvm::errs() << toString(G.takeError()) << "\n";
254     return 1;
255   }
256 
257   ArgumentsAdjuster ArgAdjuster;
258   if (!DoxygenOnly)
259     ArgAdjuster = combineAdjusters(
260         getInsertArgumentAdjuster("-fparse-all-comments",
261                                   tooling::ArgumentInsertPosition::END),
262         ArgAdjuster);
263 
264   clang::doc::ClangDocContext CDCtx = {
265       Executor->get()->getExecutionContext(),
266       ProjectName,
267       PublicOnly,
268       OutDirectory,
269       SourceRoot,
270       RepositoryUrl,
271       {UserStylesheets.begin(), UserStylesheets.end()}
272   };
273 
274   if (Format == "html") {
275     if (auto Err = getHtmlAssetFiles(argv[0], CDCtx)) {
276       llvm::errs() << toString(std::move(Err)) << "\n";
277       return 1;
278     }
279   }
280 
281   // Mapping phase
282   llvm::outs() << "Mapping decls...\n";
283   auto Err =
284       Executor->get()->execute(doc::newMapperActionFactory(CDCtx), ArgAdjuster);
285   if (Err) {
286     if (IgnoreMappingFailures)
287       llvm::errs() << "Error mapping decls in files. Clang-doc will ignore "
288                       "these files and continue:\n"
289                    << toString(std::move(Err)) << "\n";
290     else {
291       llvm::errs() << toString(std::move(Err)) << "\n";
292       return 1;
293     }
294   }
295 
296   // Collect values into output by key.
297   // In ToolResults, the Key is the hashed USR and the value is the
298   // bitcode-encoded representation of the Info object.
299   llvm::outs() << "Collecting infos...\n";
300   llvm::StringMap<std::vector<StringRef>> USRToBitcode;
301   Executor->get()->getToolResults()->forEachResult(
302       [&](StringRef Key, StringRef Value) {
303         USRToBitcode[Key].emplace_back(Value);
304       });
305 
306   // Collects all Infos according to their unique USR value. This map is added
307   // to from the thread pool below and is protected by the USRToInfoMutex.
308   llvm::sys::Mutex USRToInfoMutex;
309   llvm::StringMap<std::unique_ptr<doc::Info>> USRToInfo;
310 
311   // First reducing phase (reduce all decls into one info per decl).
312   llvm::outs() << "Reducing " << USRToBitcode.size() << " infos...\n";
313   std::atomic<bool> Error;
314   Error = false;
315   llvm::sys::Mutex IndexMutex;
316   // ExecutorConcurrency is a flag exposed by AllTUsExecution.h
317   llvm::DefaultThreadPool Pool(llvm::hardware_concurrency(ExecutorConcurrency));
318   for (auto &Group : USRToBitcode) {
319     Pool.async([&]() {
320       std::vector<std::unique_ptr<doc::Info>> Infos;
321       for (auto &Bitcode : Group.getValue()) {
322         llvm::BitstreamCursor Stream(Bitcode);
323         doc::ClangDocBitcodeReader Reader(Stream);
324         auto ReadInfos = Reader.readBitcode();
325         if (!ReadInfos) {
326           llvm::errs() << toString(ReadInfos.takeError()) << "\n";
327           Error = true;
328           return;
329         }
330         std::move(ReadInfos->begin(), ReadInfos->end(),
331                   std::back_inserter(Infos));
332       }
333 
334       auto Reduced = doc::mergeInfos(Infos);
335       if (!Reduced) {
336         llvm::errs() << llvm::toString(Reduced.takeError());
337         return;
338       }
339 
340       // Add a reference to this Info in the Index
341       {
342         std::lock_guard<llvm::sys::Mutex> Guard(IndexMutex);
343         clang::doc::Generator::addInfoToIndex(CDCtx.Idx, Reduced.get().get());
344       }
345 
346       // Save in the result map (needs a lock due to threaded access).
347       {
348         std::lock_guard<llvm::sys::Mutex> Guard(USRToInfoMutex);
349         USRToInfo[Group.getKey()] = std::move(Reduced.get());
350       }
351     });
352   }
353 
354   Pool.wait();
355 
356   if (Error)
357     return 1;
358 
359   sortUsrToInfo(USRToInfo);
360 
361   // Ensure the root output directory exists.
362   if (std::error_code Err = llvm::sys::fs::create_directories(OutDirectory);
363       Err != std::error_code()) {
364     llvm::errs() << "Failed to create directory '" << OutDirectory << "'\n";
365     return 1;
366   }
367 
368   // Run the generator.
369   llvm::outs() << "Generating docs...\n";
370   if (auto Err =
371           G->get()->generateDocs(OutDirectory, std::move(USRToInfo), CDCtx)) {
372     llvm::errs() << toString(std::move(Err)) << "\n";
373     return 1;
374   }
375 
376   llvm::outs() << "Generating assets for docs...\n";
377   Err = G->get()->createResources(CDCtx);
378   if (Err) {
379     llvm::outs() << "warning: " << toString(std::move(Err)) << "\n";
380   }
381 
382   return 0;
383 }
384