clang-tools-extra/clangd/TidyProvider.cpp

   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 "../clang-tidy/ClangTidyModuleRegistry.h"
  11 #include "../clang-tidy/ClangTidyOptions.h"
  12 #include "Config.h"
  13 #include "support/FileCache.h"
  14 #include "support/Logger.h"
  15 #include "support/Path.h"
  16 #include "support/ThreadsafeFS.h"
  17 #include "llvm/ADT/STLExtras.h"
  18 #include "llvm/ADT/SmallString.h"
  19 #include "llvm/ADT/StringExtras.h"
  20 #include "llvm/ADT/StringSet.h"
  21 #include "llvm/Support/Allocator.h"
  22 #include "llvm/Support/Process.h"
  23 #include "llvm/Support/SourceMgr.h"
  24 #include <memory>
  25 #include <optional>
  26
  27 namespace clang {
  28 namespace clangd {
  29 namespace {
  30
  31 // Access to config from a .clang-tidy file, caching IO and parsing.
  32 class DotClangTidyCache : private FileCache {
  33   // We cache and expose shared_ptr to avoid copying the value on every lookup
  34   // when we're ultimately just going to pass it to mergeWith.
  35   mutable std::shared_ptr<const tidy::ClangTidyOptions> Value;
  36
  37 public:
  38   DotClangTidyCache(PathRef Path) : FileCache(Path) {}
  39
  40   std::shared_ptr<const tidy::ClangTidyOptions>
  41   get(const ThreadsafeFS &TFS,
  42       std::chrono::steady_clock::time_point FreshTime) const {
  43     std::shared_ptr<const tidy::ClangTidyOptions> Result;
  44     read(
  45         TFS, FreshTime,
  46         [this](std::optional<llvm::StringRef> Data) {
  47           Value.reset();
  48           if (Data && !Data->empty()) {
  49             tidy::DiagCallback Diagnostics = [](const llvm::SMDiagnostic &D) {
  50               switch (D.getKind()) {
  51               case llvm::SourceMgr::DK_Error:
  52                 elog("tidy-config error at {0}:{1}:{2}: {3}", D.getFilename(),
  53                      D.getLineNo(), D.getColumnNo(), D.getMessage());
  54                 break;
  55               case llvm::SourceMgr::DK_Warning:
  56                 log("tidy-config warning at {0}:{1}:{2}: {3}", D.getFilename(),
  57                     D.getLineNo(), D.getColumnNo(), D.getMessage());
  58                 break;
  59               case llvm::SourceMgr::DK_Note:
  60               case llvm::SourceMgr::DK_Remark:
  61                 vlog("tidy-config note at {0}:{1}:{2}: {3}", D.getFilename(),
  62                      D.getLineNo(), D.getColumnNo(), D.getMessage());
  63                 break;
  64               }
  65             };
  66             if (auto Parsed = tidy::parseConfigurationWithDiags(
  67                     llvm::MemoryBufferRef(*Data, path()), Diagnostics))
  68               Value = std::make_shared<const tidy::ClangTidyOptions>(
  69                   std::move(*Parsed));
  70             else
  71               elog("Error parsing clang-tidy configuration in {0}: {1}", path(),
  72                    Parsed.getError().message());
  73           }
  74         },
  75         [&]() { Result = Value; });
  76     return Result;
  77   }
  78 };
  79
  80 // Access to combined config from .clang-tidy files governing a source file.
  81 // Each config file is cached and the caches are shared for affected sources.
  82 //
  83 // FIXME: largely duplicates config::Provider::fromAncestorRelativeYAMLFiles.
  84 // Potentially useful for compile_commands.json too. Extract?
  85 class DotClangTidyTree {
  86   const ThreadsafeFS &FS;
  87   std::string RelPath;
  88   std::chrono::steady_clock::duration MaxStaleness;
  89
  90   mutable std::mutex Mu;
  91   // Keys are the ancestor directory, not the actual config path within it.
  92   // We only insert into this map, so pointers to values are stable forever.
  93   // Mutex guards the map itself, not the values (which are threadsafe).
  94   mutable llvm::StringMap<DotClangTidyCache> Cache;
  95
  96 public:
  97   DotClangTidyTree(const ThreadsafeFS &FS)
  98       : FS(FS), RelPath(".clang-tidy"), MaxStaleness(std::chrono::seconds(5)) {}
  99
 100   void apply(tidy::ClangTidyOptions &Result, PathRef AbsPath) {
 101     namespace path = llvm::sys::path;
 102     assert(path::is_absolute(AbsPath));
 103
 104     // Compute absolute paths to all ancestors (substrings of P.Path).
 105     // Ensure cache entries for each ancestor exist in the map.
 106     llvm::SmallVector<DotClangTidyCache *> Caches;
 107     {
 108       std::lock_guard<std::mutex> Lock(Mu);
 109       for (auto Ancestor = absoluteParent(AbsPath); !Ancestor.empty();
 110            Ancestor = absoluteParent(Ancestor)) {
 111         auto It = Cache.find(Ancestor);
 112         // Assemble the actual config file path only if needed.
 113         if (It == Cache.end()) {
 114           llvm::SmallString<256> ConfigPath = Ancestor;
 115           path::append(ConfigPath, RelPath);
 116           It = Cache.try_emplace(Ancestor, ConfigPath.str()).first;
 117         }
 118         Caches.push_back(&It->second);
 119       }
 120     }
 121     // Finally query each individual file.
 122     // This will take a (per-file) lock for each file that actually exists.
 123     std::chrono::steady_clock::time_point FreshTime =
 124         std::chrono::steady_clock::now() - MaxStaleness;
 125     llvm::SmallVector<std::shared_ptr<const tidy::ClangTidyOptions>>
 126         OptionStack;
 127     for (const DotClangTidyCache *Cache : Caches)
 128       if (auto Config = Cache->get(FS, FreshTime)) {
 129         OptionStack.push_back(std::move(Config));
 130         if (!OptionStack.back()->InheritParentConfig.value_or(false))
 131           break;
 132       }
 133     unsigned Order = 1u;
 134     for (auto &Option : llvm::reverse(OptionStack))
 135       Result.mergeWith(*Option, Order++);
 136   }
 137 };
 138
 139 } // namespace
 140
 141 static void mergeCheckList(std::optional<std::string> &Checks,
 142                            llvm::StringRef List) {
 143   if (List.empty())
 144     return;
 145   if (!Checks || Checks->empty()) {
 146     Checks.emplace(List);
 147     return;
 148   }
 149   *Checks = llvm::join_items(",", *Checks, List);
 150 }
 151
 152 TidyProviderRef provideEnvironment() {
 153   static const std::optional<std::string> User = [] {
 154     std::optional<std::string> Ret = llvm::sys::Process::GetEnv("USER");
 155 #ifdef _WIN32
 156     if (!Ret)
 157       return llvm::sys::Process::GetEnv("USERNAME");
 158 #endif
 159     return Ret;
 160   }();
 161
 162   if (User)
 163     return
 164         [](tidy::ClangTidyOptions &Opts, llvm::StringRef) { Opts.User = User; };
 165   // FIXME: Once function_ref and unique_function operator= operators handle
 166   // null values, this can return null.
 167   return [](tidy::ClangTidyOptions &, llvm::StringRef) {};
 168 }
 169
 170 TidyProviderRef provideDefaultChecks() {
 171   // These default checks are chosen for:
 172   //  - low false-positive rate
 173   //  - providing a lot of value
 174   //  - being reasonably efficient
 175   static const std::string DefaultChecks = llvm::join_items(
 176       ",", "readability-misleading-indentation", "readability-deleted-default",
 177       "bugprone-integer-division", "bugprone-sizeof-expression",
 178       "bugprone-suspicious-missing-comma", "bugprone-unused-raii",
 179       "bugprone-unused-return-value", "misc-unused-using-decls",
 180       "misc-unused-alias-decls", "misc-definitions-in-headers");
 181   return [](tidy::ClangTidyOptions &Opts, llvm::StringRef) {
 182     if (!Opts.Checks || Opts.Checks->empty())
 183       Opts.Checks = DefaultChecks;
 184   };
 185 }
 186
 187 TidyProvider addTidyChecks(llvm::StringRef Checks,
 188                            llvm::StringRef WarningsAsErrors) {
 189   return [Checks = std::string(Checks),
 190           WarningsAsErrors = std::string(WarningsAsErrors)](
 191              tidy::ClangTidyOptions &Opts, llvm::StringRef) {
 192     mergeCheckList(Opts.Checks, Checks);
 193     mergeCheckList(Opts.WarningsAsErrors, WarningsAsErrors);
 194   };
 195 }
 196
 197 TidyProvider disableUnusableChecks(llvm::ArrayRef<std::string> ExtraBadChecks) {
 198   constexpr llvm::StringLiteral Seperator(",");
 199   static const std::string BadChecks = llvm::join_items(
 200       Seperator,
 201       // We want this list to start with a seperator to
 202       // simplify appending in the lambda. So including an
 203       // empty string here will force that.
 204       "",
 205       // include-cleaner is directly integrated in IncludeCleaner.cpp
 206       "-misc-include-cleaner",
 207
 208       // ----- False Positives -----
 209
 210       // Check relies on seeing ifndef/define/endif directives,
 211       // clangd doesn't replay those when using a preamble.
 212       "-llvm-header-guard", "-modernize-macro-to-enum",
 213
 214       // ----- Crashing Checks -----
 215
 216       // Check can choke on invalid (intermediate) c++
 217       // code, which is often the case when clangd
 218       // tries to build an AST.
 219       "-bugprone-use-after-move",
 220       // Alias for bugprone-use-after-move.
 221       "-hicpp-invalid-access-moved",
 222       // Check uses dataflow analysis, which might hang/crash unexpectedly on
 223       // incomplete code.
 224       "-bugprone-unchecked-optional-access",
 225
 226       // ----- Performance problems -----
 227
 228       // This check runs expensive analysis for each variable.
 229       // It has been observed to increase reparse time by 10x.
 230       "-misc-const-correctness");
 231
 232   size_t Size = BadChecks.size();
 233   for (const std::string &Str : ExtraBadChecks) {
 234     if (Str.empty())
 235       continue;
 236     Size += Seperator.size();
 237     if (LLVM_LIKELY(Str.front() != '-'))
 238       ++Size;
 239     Size += Str.size();
 240   }
 241   std::string DisableGlob;
 242   DisableGlob.reserve(Size);
 243   DisableGlob += BadChecks;
 244   for (const std::string &Str : ExtraBadChecks) {
 245     if (Str.empty())
 246       continue;
 247     DisableGlob += Seperator;
 248     if (LLVM_LIKELY(Str.front() != '-'))
 249       DisableGlob.push_back('-');
 250     DisableGlob += Str;
 251   }
 252
 253   return [DisableList(std::move(DisableGlob))](tidy::ClangTidyOptions &Opts,
 254                                                llvm::StringRef) {
 255     if (Opts.Checks && !Opts.Checks->empty())
 256       Opts.Checks->append(DisableList);
 257   };
 258 }
 259
 260 TidyProviderRef provideClangdConfig() {
 261   return [](tidy::ClangTidyOptions &Opts, llvm::StringRef) {
 262     const auto &CurTidyConfig = Config::current().Diagnostics.ClangTidy;
 263     if (!CurTidyConfig.Checks.empty())
 264       mergeCheckList(Opts.Checks, CurTidyConfig.Checks);
 265
 266     for (const auto &CheckOption : CurTidyConfig.CheckOptions)
 267       Opts.CheckOptions.insert_or_assign(CheckOption.getKey(),
 268                                          tidy::ClangTidyOptions::ClangTidyValue(
 269                                              CheckOption.getValue(), 10000U));
 270   };
 271 }
 272
 273 TidyProvider provideClangTidyFiles(ThreadsafeFS &TFS) {
 274   return [Tree = std::make_unique<DotClangTidyTree>(TFS)](
 275              tidy::ClangTidyOptions &Opts, llvm::StringRef Filename) {
 276     Tree->apply(Opts, Filename);
 277   };
 278 }
 279
 280 TidyProvider combine(std::vector<TidyProvider> Providers) {
 281   // FIXME: Once function_ref and unique_function operator= operators handle
 282   // null values, we should filter out any Providers that are null. Right now we
 283   // have to ensure we dont pass any providers that are null.
 284   return [Providers(std::move(Providers))](tidy::ClangTidyOptions &Opts,
 285                                            llvm::StringRef Filename) {
 286     for (const auto &Provider : Providers)
 287       Provider(Opts, Filename);
 288   };
 289 }
 290
 291 tidy::ClangTidyOptions getTidyOptionsForFile(TidyProviderRef Provider,
 292                                              llvm::StringRef Filename) {
 293   // getDefaults instantiates all check factories, which are registered at link
 294   // time. So cache the results once.
 295   static const auto *DefaultOpts = [] {
 296     auto *Opts = new tidy::ClangTidyOptions;
 297     *Opts = tidy::ClangTidyOptions::getDefaults();
 298     Opts->Checks->clear();
 299     return Opts;
 300   }();
 301   auto Opts = *DefaultOpts;
 302   if (Provider)
 303     Provider(Opts, Filename);
 304   return Opts;
 305 }
 306
 307 bool isRegisteredTidyCheck(llvm::StringRef Check) {
 308   assert(!Check.empty());
 309   assert(!Check.contains('*') && !Check.contains(',') &&
 310          "isRegisteredCheck doesn't support globs");
 311   assert(Check.ltrim().front() != '-');
 312
 313   static const llvm::StringSet<llvm::BumpPtrAllocator> AllChecks = [] {
 314     llvm::StringSet<llvm::BumpPtrAllocator> Result;
 315     tidy::ClangTidyCheckFactories Factories;
 316     for (tidy::ClangTidyModuleRegistry::entry E :
 317          tidy::ClangTidyModuleRegistry::entries())
 318       E.instantiate()->addCheckFactories(Factories);
 319     for (const auto &Factory : Factories)
 320       Result.insert(Factory.getKey());
 321     return Result;
 322   }();
 323
 324   return AllChecks.contains(Check);
 325 }
 326
 327 std::optional<bool> isFastTidyCheck(llvm::StringRef Check) {
 328   static auto &Fast = *new llvm::StringMap<bool>{
 329 #define FAST(CHECK, TIME) {#CHECK,true},
 330 #define SLOW(CHECK, TIME) {#CHECK,false},
 331 #include "TidyFastChecks.inc"
 332   };
 333   if (auto It = Fast.find(Check); It != Fast.end())
 334     return It->second;
 335   return std::nullopt;
 336 }
 337
 338 } // namespace clangd
 339 } // namespace clang