1 //===--- TidyProvider.cpp - create options for running clang-tidy----------===//
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 "TidyProvider.h"
10 #include "Config.h"
11 #include "support/FileCache.h"
12 #include "support/Logger.h"
13 #include "support/ThreadsafeFS.h"
14 #include "llvm/ADT/STLExtras.h"
15 #include "llvm/ADT/SmallString.h"
16 #include "llvm/ADT/StringExtras.h"
17 #include "llvm/Support/ErrorHandling.h"
18 #include "llvm/Support/Process.h"
19 #include "llvm/Support/VirtualFileSystem.h"
20 #include <memory>
21
22 namespace clang {
23 namespace clangd {
24 namespace {
25
26 // Access to config from a .clang-tidy file, caching IO and parsing.
27 class DotClangTidyCache : private FileCache {
28 // We cache and expose shared_ptr to avoid copying the value on every lookup
29 // when we're ultimately just going to pass it to mergeWith.
30 mutable std::shared_ptr<const tidy::ClangTidyOptions> Value;
31
32 public:
DotClangTidyCache(PathRef Path)33 DotClangTidyCache(PathRef Path) : FileCache(Path) {}
34
35 std::shared_ptr<const tidy::ClangTidyOptions>
get(const ThreadsafeFS & TFS,std::chrono::steady_clock::time_point FreshTime) const36 get(const ThreadsafeFS &TFS,
37 std::chrono::steady_clock::time_point FreshTime) const {
38 std::shared_ptr<const tidy::ClangTidyOptions> Result;
39 read(
40 TFS, FreshTime,
41 [this](llvm::Optional<llvm::StringRef> Data) {
42 Value.reset();
43 if (Data && !Data->empty()) {
44 if (auto Parsed = tidy::parseConfiguration(*Data))
45 Value = std::make_shared<const tidy::ClangTidyOptions>(
46 std::move(*Parsed));
47 else
48 elog("Error parsing clang-tidy configuration in {0}: {1}", path(),
49 Parsed.getError().message());
50 }
51 },
52 [&]() { Result = Value; });
53 return Result;
54 }
55 };
56
57 // Access to combined config from .clang-tidy files governing a source file.
58 // Each config file is cached and the caches are shared for affected sources.
59 //
60 // FIXME: largely duplicates config::Provider::fromAncestorRelativeYAMLFiles.
61 // Potentially useful for compile_commands.json too. Extract?
62 class DotClangTidyTree {
63 const ThreadsafeFS &FS;
64 std::string RelPath;
65 std::chrono::steady_clock::duration MaxStaleness;
66
67 mutable std::mutex Mu;
68 // Keys are the ancestor directory, not the actual config path within it.
69 // We only insert into this map, so pointers to values are stable forever.
70 // Mutex guards the map itself, not the values (which are threadsafe).
71 mutable llvm::StringMap<DotClangTidyCache> Cache;
72
73 public:
DotClangTidyTree(const ThreadsafeFS & FS)74 DotClangTidyTree(const ThreadsafeFS &FS)
75 : FS(FS), RelPath(".clang-tidy"), MaxStaleness(std::chrono::seconds(5)) {}
76
apply(tidy::ClangTidyOptions & Result,PathRef AbsPath)77 void apply(tidy::ClangTidyOptions &Result, PathRef AbsPath) {
78 namespace path = llvm::sys::path;
79 assert(path::is_absolute(AbsPath));
80
81 // Compute absolute paths to all ancestors (substrings of P.Path).
82 // Ensure cache entries for each ancestor exist in the map.
83 llvm::StringRef Parent = path::parent_path(AbsPath);
84 llvm::SmallVector<DotClangTidyCache *, 8> Caches;
85 {
86 std::lock_guard<std::mutex> Lock(Mu);
87 for (auto I = path::begin(Parent, path::Style::posix),
88 E = path::end(Parent);
89 I != E; ++I) {
90 assert(I->end() >= Parent.begin() && I->end() <= Parent.end() &&
91 "Canonical path components should be substrings");
92 llvm::StringRef Ancestor(Parent.begin(), I->end() - Parent.begin());
93 auto It = Cache.find(Ancestor);
94
95 // Assemble the actual config file path only if needed.
96 if (It == Cache.end()) {
97 llvm::SmallString<256> ConfigPath = Ancestor;
98 path::append(ConfigPath, RelPath);
99 It = Cache.try_emplace(Ancestor, ConfigPath.str()).first;
100 }
101 Caches.push_back(&It->second);
102 }
103 }
104 // Finally query each individual file.
105 // This will take a (per-file) lock for each file that actually exists.
106 std::chrono::steady_clock::time_point FreshTime =
107 std::chrono::steady_clock::now() - MaxStaleness;
108 llvm::SmallVector<std::shared_ptr<const tidy::ClangTidyOptions>, 4>
109 OptionStack;
110 for (const DotClangTidyCache *Cache : Caches)
111 if (auto Config = Cache->get(FS, FreshTime)) {
112 OptionStack.push_back(std::move(Config));
113 if (!OptionStack.back()->InheritParentConfig.getValueOr(false))
114 break;
115 }
116 unsigned Order = 1u;
117 for (auto &Option : llvm::reverse(OptionStack))
118 Result.mergeWith(*Option, Order++);
119 }
120 };
121
122 } // namespace
123
mergeCheckList(llvm::Optional<std::string> & Checks,llvm::StringRef List)124 static void mergeCheckList(llvm::Optional<std::string> &Checks,
125 llvm::StringRef List) {
126 if (List.empty())
127 return;
128 if (!Checks || Checks->empty()) {
129 Checks.emplace(List);
130 return;
131 }
132 *Checks = llvm::join_items(",", *Checks, List);
133 }
134
provideEnvironment()135 TidyProviderRef provideEnvironment() {
136 static const llvm::Optional<std::string> User = [] {
137 llvm::Optional<std::string> Ret = llvm::sys::Process::GetEnv("USER");
138 #ifdef _WIN32
139 if (!Ret)
140 return llvm::sys::Process::GetEnv("USERNAME");
141 #endif
142 return Ret;
143 }();
144
145 if (User)
146 return
147 [](tidy::ClangTidyOptions &Opts, llvm::StringRef) { Opts.User = User; };
148 // FIXME: Once function_ref and unique_function operator= operators handle
149 // null values, this can return null.
150 return [](tidy::ClangTidyOptions &, llvm::StringRef) {};
151 }
152
provideDefaultChecks()153 TidyProviderRef provideDefaultChecks() {
154 // These default checks are chosen for:
155 // - low false-positive rate
156 // - providing a lot of value
157 // - being reasonably efficient
158 static const std::string DefaultChecks = llvm::join_items(
159 ",", "readability-misleading-indentation", "readability-deleted-default",
160 "bugprone-integer-division", "bugprone-sizeof-expression",
161 "bugprone-suspicious-missing-comma", "bugprone-unused-raii",
162 "bugprone-unused-return-value", "misc-unused-using-decls",
163 "misc-unused-alias-decls", "misc-definitions-in-headers");
164 return [](tidy::ClangTidyOptions &Opts, llvm::StringRef) {
165 if (!Opts.Checks || Opts.Checks->empty())
166 Opts.Checks = DefaultChecks;
167 };
168 }
169
addTidyChecks(llvm::StringRef Checks,llvm::StringRef WarningsAsErrors)170 TidyProvider addTidyChecks(llvm::StringRef Checks,
171 llvm::StringRef WarningsAsErrors) {
172 return [Checks = std::string(Checks),
173 WarningsAsErrors = std::string(WarningsAsErrors)](
174 tidy::ClangTidyOptions &Opts, llvm::StringRef) {
175 mergeCheckList(Opts.Checks, Checks);
176 mergeCheckList(Opts.WarningsAsErrors, WarningsAsErrors);
177 };
178 }
179
disableUnusableChecks(llvm::ArrayRef<std::string> ExtraBadChecks)180 TidyProvider disableUnusableChecks(llvm::ArrayRef<std::string> ExtraBadChecks) {
181 constexpr llvm::StringLiteral Seperator(",");
182 static const std::string BadChecks =
183 llvm::join_items(Seperator,
184 // We want this list to start with a seperator to
185 // simplify appending in the lambda. So including an
186 // empty string here will force that.
187 "",
188 // ----- False Positives -----
189
190 // Check relies on seeing ifndef/define/endif directives,
191 // clangd doesn't replay those when using a preamble.
192 "-llvm-header-guard",
193
194 // ----- Crashing Checks -----
195
196 // Check can choke on invalid (intermediate) c++
197 // code, which is often the case when clangd
198 // tries to build an AST.
199 "-bugprone-use-after-move");
200
201 size_t Size = BadChecks.size();
202 for (const std::string &Str : ExtraBadChecks) {
203 if (Str.empty())
204 continue;
205 Size += Seperator.size();
206 if (LLVM_LIKELY(Str.front() != '-'))
207 ++Size;
208 Size += Str.size();
209 }
210 std::string DisableGlob;
211 DisableGlob.reserve(Size);
212 DisableGlob += BadChecks;
213 for (const std::string &Str : ExtraBadChecks) {
214 if (Str.empty())
215 continue;
216 DisableGlob += Seperator;
217 if (LLVM_LIKELY(Str.front() != '-'))
218 DisableGlob.push_back('-');
219 DisableGlob += Str;
220 }
221
222 return [DisableList(std::move(DisableGlob))](tidy::ClangTidyOptions &Opts,
223 llvm::StringRef) {
224 if (Opts.Checks && !Opts.Checks->empty())
225 Opts.Checks->append(DisableList);
226 };
227 }
228
provideClangdConfig()229 TidyProviderRef provideClangdConfig() {
230 return [](tidy::ClangTidyOptions &Opts, llvm::StringRef) {
231 const auto &CurTidyConfig = Config::current().ClangTidy;
232 if (!CurTidyConfig.Checks.empty())
233 mergeCheckList(Opts.Checks, CurTidyConfig.Checks);
234
235 for (const auto &CheckOption : CurTidyConfig.CheckOptions)
236 Opts.CheckOptions.insert_or_assign(CheckOption.getKey(),
237 tidy::ClangTidyOptions::ClangTidyValue(
238 CheckOption.getValue(), 10000U));
239 };
240 }
241
provideClangTidyFiles(ThreadsafeFS & TFS)242 TidyProvider provideClangTidyFiles(ThreadsafeFS &TFS) {
243 return [Tree = std::make_unique<DotClangTidyTree>(TFS)](
244 tidy::ClangTidyOptions &Opts, llvm::StringRef Filename) {
245 Tree->apply(Opts, Filename);
246 };
247 }
248
combine(std::vector<TidyProvider> Providers)249 TidyProvider combine(std::vector<TidyProvider> Providers) {
250 // FIXME: Once function_ref and unique_function operator= operators handle
251 // null values, we should filter out any Providers that are null. Right now we
252 // have to ensure we dont pass any providers that are null.
253 return [Providers(std::move(Providers))](tidy::ClangTidyOptions &Opts,
254 llvm::StringRef Filename) {
255 for (const auto &Provider : Providers)
256 Provider(Opts, Filename);
257 };
258 }
259
getTidyOptionsForFile(TidyProviderRef Provider,llvm::StringRef Filename)260 tidy::ClangTidyOptions getTidyOptionsForFile(TidyProviderRef Provider,
261 llvm::StringRef Filename) {
262 tidy::ClangTidyOptions Opts = tidy::ClangTidyOptions::getDefaults();
263 Opts.Checks->clear();
264 if (Provider)
265 Provider(Opts, Filename);
266 return Opts;
267 }
268 } // namespace clangd
269 } // namespace clang
270