1 //===- CheckerRegistry.cpp - Maintains all available checkers -------------===//
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/StaticAnalyzer/Frontend/CheckerRegistry.h"
10 #include "clang/Basic/Diagnostic.h"
11 #include "clang/Basic/LLVM.h"
12 #include "clang/Driver/DriverDiagnostic.h"
13 #include "clang/Frontend/FrontendDiagnostic.h"
14 #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
15 #include "clang/StaticAnalyzer/Core/AnalyzerOptions.h"
16 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
17 #include "llvm/ADT/STLExtras.h"
18 #include "llvm/ADT/SetVector.h"
19 #include "llvm/ADT/StringMap.h"
20 #include "llvm/ADT/StringRef.h"
21 #include "llvm/Support/DynamicLibrary.h"
22 #include "llvm/Support/Path.h"
23 #include "llvm/Support/raw_ostream.h"
24 #include <algorithm>
25 
26 using namespace clang;
27 using namespace ento;
28 using llvm::sys::DynamicLibrary;
29 
30 //===----------------------------------------------------------------------===//
31 // Utilities.
32 //===----------------------------------------------------------------------===//
33 
34 using RegisterCheckersFn = void (*)(CheckerRegistry &);
35 
36 static bool isCompatibleAPIVersion(const char *VersionString) {
37   // If the version string is null, its not an analyzer plugin.
38   if (!VersionString)
39     return false;
40 
41   // For now, none of the static analyzer API is considered stable.
42   // Versions must match exactly.
43   return strcmp(VersionString, CLANG_ANALYZER_API_VERSION_STRING) == 0;
44 }
45 
46 namespace {
47 template <class T> struct FullNameLT {
48   bool operator()(const T &Lhs, const T &Rhs) {
49     return Lhs.FullName < Rhs.FullName;
50   }
51 };
52 
53 using PackageNameLT = FullNameLT<CheckerRegistry::PackageInfo>;
54 using CheckerNameLT = FullNameLT<CheckerRegistry::CheckerInfo>;
55 } // end of anonymous namespace
56 
57 template <class CheckerOrPackageInfoList>
58 static std::conditional_t<std::is_const<CheckerOrPackageInfoList>::value,
59                           typename CheckerOrPackageInfoList::const_iterator,
60                           typename CheckerOrPackageInfoList::iterator>
61 binaryFind(CheckerOrPackageInfoList &Collection, StringRef FullName) {
62 
63   using CheckerOrPackage = typename CheckerOrPackageInfoList::value_type;
64   using CheckerOrPackageFullNameLT = FullNameLT<CheckerOrPackage>;
65 
66   assert(llvm::is_sorted(Collection, CheckerOrPackageFullNameLT{}) &&
67          "In order to efficiently gather checkers/packages, this function "
68          "expects them to be already sorted!");
69 
70   return llvm::lower_bound(Collection, CheckerOrPackage(FullName),
71                            CheckerOrPackageFullNameLT{});
72 }
73 
74 static constexpr char PackageSeparator = '.';
75 
76 static bool isInPackage(const CheckerRegistry::CheckerInfo &Checker,
77                         StringRef PackageName) {
78   // Does the checker's full name have the package as a prefix?
79   if (!Checker.FullName.startswith(PackageName))
80     return false;
81 
82   // Is the package actually just the name of a specific checker?
83   if (Checker.FullName.size() == PackageName.size())
84     return true;
85 
86   // Is the checker in the package (or a subpackage)?
87   if (Checker.FullName[PackageName.size()] == PackageSeparator)
88     return true;
89 
90   return false;
91 }
92 
93 //===----------------------------------------------------------------------===//
94 // Methods of CmdLineOption, PackageInfo and CheckerInfo.
95 //===----------------------------------------------------------------------===//
96 
97 LLVM_DUMP_METHOD void
98 CheckerRegistry::CmdLineOption::dumpToStream(llvm::raw_ostream &Out) const {
99   // The description can be just checked in Checkers.inc, the point here is to
100   // debug whether we succeeded in parsing it.
101   Out << OptionName << " (" << OptionType << ", "
102       << (IsHidden ? "hidden, " : "") << DevelopmentStatus << ") default: \""
103       << DefaultValStr;
104 }
105 
106 static StringRef toString(CheckerRegistry::StateFromCmdLine Kind) {
107   switch (Kind) {
108   case CheckerRegistry::StateFromCmdLine::State_Disabled:
109     return "Disabled";
110   case CheckerRegistry::StateFromCmdLine::State_Enabled:
111     return "Enabled";
112   case CheckerRegistry::StateFromCmdLine::State_Unspecified:
113     return "Unspecified";
114   }
115 }
116 
117 LLVM_DUMP_METHOD void
118 CheckerRegistry::CheckerInfo::dumpToStream(llvm::raw_ostream &Out) const {
119   // The description can be just checked in Checkers.inc, the point here is to
120   // debug whether we succeeded in parsing it. Same with documentation uri.
121   Out << FullName << " (" << toString(State) << (IsHidden ? ", hidden" : "")
122       << ")\n";
123   Out << "  Options:\n";
124   for (const CmdLineOption &Option : CmdLineOptions) {
125     Out << "    ";
126     Option.dumpToStream(Out);
127     Out << '\n';
128   }
129   Out << "  Dependencies:\n";
130   for (const CheckerInfo *Dependency : Dependencies) {
131     Out << "  " << Dependency->FullName << '\n';
132   }
133 }
134 
135 LLVM_DUMP_METHOD void
136 CheckerRegistry::PackageInfo::dumpToStream(llvm::raw_ostream &Out) const {
137   Out << FullName << "\n";
138   Out << "  Options:\n";
139   for (const CmdLineOption &Option : CmdLineOptions) {
140     Out << "    ";
141     Option.dumpToStream(Out);
142     Out << '\n';
143   }
144 }
145 
146 //===----------------------------------------------------------------------===//
147 // Methods of CheckerRegistry.
148 //===----------------------------------------------------------------------===//
149 
150 CheckerRegistry::CheckerInfoListRange
151 CheckerRegistry::getMutableCheckersForCmdLineArg(StringRef CmdLineArg) {
152   auto It = binaryFind(Checkers, CmdLineArg);
153 
154   if (!isInPackage(*It, CmdLineArg))
155     return {Checkers.end(), Checkers.end()};
156 
157   // See how large the package is.
158   // If the package doesn't exist, assume the option refers to a single
159   // checker.
160   size_t Size = 1;
161   llvm::StringMap<size_t>::const_iterator PackageSize =
162       PackageSizes.find(CmdLineArg);
163 
164   if (PackageSize != PackageSizes.end())
165     Size = PackageSize->getValue();
166 
167   return {It, It + Size};
168 }
169 
170 CheckerRegistry::CheckerRegistry(
171     ArrayRef<std::string> Plugins, DiagnosticsEngine &Diags,
172     AnalyzerOptions &AnOpts,
173     ArrayRef<std::function<void(CheckerRegistry &)>> CheckerRegistrationFns)
174     : Diags(Diags), AnOpts(AnOpts) {
175 
176   // Register builtin checkers.
177 #define GET_CHECKERS
178 #define CHECKER(FULLNAME, CLASS, HELPTEXT, DOC_URI, IS_HIDDEN)                 \
179   addChecker(register##CLASS, shouldRegister##CLASS, FULLNAME, HELPTEXT,       \
180              DOC_URI, IS_HIDDEN);
181 
182 #define GET_PACKAGES
183 #define PACKAGE(FULLNAME) addPackage(FULLNAME);
184 
185 #include "clang/StaticAnalyzer/Checkers/Checkers.inc"
186 #undef CHECKER
187 #undef GET_CHECKERS
188 #undef PACKAGE
189 #undef GET_PACKAGES
190 
191   // Register checkers from plugins.
192   for (const std::string &Plugin : Plugins) {
193     // Get access to the plugin.
194     std::string ErrorMsg;
195     DynamicLibrary Lib =
196         DynamicLibrary::getPermanentLibrary(Plugin.c_str(), &ErrorMsg);
197     if (!Lib.isValid()) {
198       Diags.Report(diag::err_fe_unable_to_load_plugin) << Plugin << ErrorMsg;
199       continue;
200     }
201 
202     // See if its compatible with this build of clang.
203     const char *PluginAPIVersion = static_cast<const char *>(
204         Lib.getAddressOfSymbol("clang_analyzerAPIVersionString"));
205 
206     if (!isCompatibleAPIVersion(PluginAPIVersion)) {
207       Diags.Report(diag::warn_incompatible_analyzer_plugin_api)
208           << llvm::sys::path::filename(Plugin);
209       Diags.Report(diag::note_incompatible_analyzer_plugin_api)
210           << CLANG_ANALYZER_API_VERSION_STRING << PluginAPIVersion;
211       continue;
212     }
213 
214     // Register its checkers.
215     RegisterCheckersFn RegisterPluginCheckers =
216         reinterpret_cast<RegisterCheckersFn>(
217             Lib.getAddressOfSymbol("clang_registerCheckers"));
218     if (RegisterPluginCheckers)
219       RegisterPluginCheckers(*this);
220   }
221 
222   // Register statically linked checkers, that aren't generated from the tblgen
223   // file, but rather passed their registry function as a parameter in
224   // checkerRegistrationFns.
225 
226   for (const auto &Fn : CheckerRegistrationFns)
227     Fn(*this);
228 
229   // Sort checkers for efficient collection.
230   // FIXME: Alphabetical sort puts 'experimental' in the middle.
231   // Would it be better to name it '~experimental' or something else
232   // that's ASCIIbetically last?
233   llvm::sort(Packages, PackageNameLT{});
234   llvm::sort(Checkers, CheckerNameLT{});
235 
236 #define GET_CHECKER_DEPENDENCIES
237 
238 #define CHECKER_DEPENDENCY(FULLNAME, DEPENDENCY)                               \
239   addDependency(FULLNAME, DEPENDENCY);
240 
241 #define GET_CHECKER_OPTIONS
242 #define CHECKER_OPTION(TYPE, FULLNAME, CMDFLAG, DESC, DEFAULT_VAL,             \
243                        DEVELOPMENT_STATUS, IS_HIDDEN)                          \
244   addCheckerOption(TYPE, FULLNAME, CMDFLAG, DEFAULT_VAL, DESC,                 \
245                    DEVELOPMENT_STATUS, IS_HIDDEN);
246 
247 #define GET_PACKAGE_OPTIONS
248 #define PACKAGE_OPTION(TYPE, FULLNAME, CMDFLAG, DESC, DEFAULT_VAL,             \
249                        DEVELOPMENT_STATUS, IS_HIDDEN)                          \
250   addPackageOption(TYPE, FULLNAME, CMDFLAG, DEFAULT_VAL, DESC,                 \
251                    DEVELOPMENT_STATUS, IS_HIDDEN);
252 
253 #include "clang/StaticAnalyzer/Checkers/Checkers.inc"
254 #undef CHECKER_DEPENDENCY
255 #undef GET_CHECKER_DEPENDENCIES
256 #undef CHECKER_OPTION
257 #undef GET_CHECKER_OPTIONS
258 #undef PACKAGE_OPTION
259 #undef GET_PACKAGE_OPTIONS
260 
261   resolveDependencies();
262   resolveCheckerAndPackageOptions();
263 
264   // Parse '-analyzer-checker' and '-analyzer-disable-checker' options from the
265   // command line.
266   for (const std::pair<std::string, bool> &Opt : AnOpts.CheckersAndPackages) {
267     CheckerInfoListRange CheckerForCmdLineArg =
268         getMutableCheckersForCmdLineArg(Opt.first);
269 
270     if (CheckerForCmdLineArg.begin() == CheckerForCmdLineArg.end()) {
271       Diags.Report(diag::err_unknown_analyzer_checker_or_package) << Opt.first;
272       Diags.Report(diag::note_suggest_disabling_all_checkers);
273     }
274 
275     for (CheckerInfo &checker : CheckerForCmdLineArg) {
276       checker.State = Opt.second ? StateFromCmdLine::State_Enabled
277                                  : StateFromCmdLine::State_Disabled;
278     }
279   }
280   validateCheckerOptions();
281 }
282 
283 /// Collects dependenies in \p enabledCheckers. Return None on failure.
284 LLVM_NODISCARD
285 static llvm::Optional<CheckerRegistry::CheckerInfoSet>
286 collectDependencies(const CheckerRegistry::CheckerInfo &checker,
287                     const CheckerManager &Mgr);
288 
289 void CheckerRegistry::initializeRegistry(const CheckerManager &Mgr) {
290   for (const CheckerInfo &Checker : Checkers) {
291     if (!Checker.isEnabled(Mgr))
292       continue;
293 
294     // Recursively enable its dependencies.
295     llvm::Optional<CheckerInfoSet> Deps = collectDependencies(Checker, Mgr);
296 
297     if (!Deps) {
298       // If we failed to enable any of the dependencies, don't enable this
299       // checker.
300       continue;
301     }
302 
303     // Note that set_union also preserves the order of insertion.
304     EnabledCheckers.set_union(*Deps);
305 
306     // Enable the checker.
307     EnabledCheckers.insert(&Checker);
308   }
309 }
310 
311 /// Collects dependencies in \p ret, returns false on failure.
312 static bool
313 collectDependenciesImpl(const CheckerRegistry::ConstCheckerInfoList &Deps,
314                         const CheckerManager &Mgr,
315                         CheckerRegistry::CheckerInfoSet &Ret);
316 
317 /// Collects dependenies in \p enabledCheckers. Return None on failure.
318 LLVM_NODISCARD
319 static llvm::Optional<CheckerRegistry::CheckerInfoSet>
320 collectDependencies(const CheckerRegistry::CheckerInfo &checker,
321                     const CheckerManager &Mgr) {
322 
323   CheckerRegistry::CheckerInfoSet Ret;
324   // Add dependencies to the enabled checkers only if all of them can be
325   // enabled.
326   if (!collectDependenciesImpl(checker.Dependencies, Mgr, Ret))
327     return None;
328 
329   return Ret;
330 }
331 
332 static bool
333 collectDependenciesImpl(const CheckerRegistry::ConstCheckerInfoList &Deps,
334                         const CheckerManager &Mgr,
335                         CheckerRegistry::CheckerInfoSet &Ret) {
336 
337   for (const CheckerRegistry::CheckerInfo *Dependency : Deps) {
338 
339     if (Dependency->isDisabled(Mgr))
340       return false;
341 
342     // Collect dependencies recursively.
343     if (!collectDependenciesImpl(Dependency->Dependencies, Mgr, Ret))
344       return false;
345 
346     Ret.insert(Dependency);
347   }
348 
349   return true;
350 }
351 
352 void CheckerRegistry::resolveDependencies() {
353   for (const std::pair<StringRef, StringRef> &Entry : Dependencies) {
354     auto CheckerIt = binaryFind(Checkers, Entry.first);
355     assert(CheckerIt != Checkers.end() && CheckerIt->FullName == Entry.first &&
356            "Failed to find the checker while attempting to set up its "
357            "dependencies!");
358 
359     auto DependencyIt = binaryFind(Checkers, Entry.second);
360     assert(DependencyIt != Checkers.end() &&
361            DependencyIt->FullName == Entry.second &&
362            "Failed to find the dependency of a checker!");
363 
364     CheckerIt->Dependencies.emplace_back(&*DependencyIt);
365   }
366 }
367 
368 void CheckerRegistry::addDependency(StringRef FullName, StringRef Dependency) {
369   Dependencies.emplace_back(FullName, Dependency);
370 }
371 
372 /// Insert the checker/package option to AnalyzerOptions' config table, and
373 /// validate it, if the user supplied it on the command line.
374 static void insertAndValidate(StringRef FullName,
375                               const CheckerRegistry::CmdLineOption &Option,
376                               AnalyzerOptions &AnOpts,
377                               DiagnosticsEngine &Diags) {
378 
379   std::string FullOption = (FullName + ":" + Option.OptionName).str();
380 
381   auto It =
382       AnOpts.Config.insert({FullOption, std::string(Option.DefaultValStr)});
383 
384   // Insertation was successful -- CmdLineOption's constructor will validate
385   // whether values received from plugins or TableGen files are correct.
386   if (It.second)
387     return;
388 
389   // Insertion failed, the user supplied this package/checker option on the
390   // command line. If the supplied value is invalid, we'll restore the option
391   // to it's default value, and if we're in non-compatibility mode, we'll also
392   // emit an error.
393 
394   StringRef SuppliedValue = It.first->getValue();
395 
396   if (Option.OptionType == "bool") {
397     if (SuppliedValue != "true" && SuppliedValue != "false") {
398       if (AnOpts.ShouldEmitErrorsOnInvalidConfigValue) {
399         Diags.Report(diag::err_analyzer_checker_option_invalid_input)
400             << FullOption << "a boolean value";
401       }
402 
403       It.first->setValue(std::string(Option.DefaultValStr));
404     }
405     return;
406   }
407 
408   if (Option.OptionType == "int") {
409     int Tmp;
410     bool HasFailed = SuppliedValue.getAsInteger(0, Tmp);
411     if (HasFailed) {
412       if (AnOpts.ShouldEmitErrorsOnInvalidConfigValue) {
413         Diags.Report(diag::err_analyzer_checker_option_invalid_input)
414             << FullOption << "an integer value";
415       }
416 
417       It.first->setValue(std::string(Option.DefaultValStr));
418     }
419     return;
420   }
421 }
422 
423 template <class T>
424 static void
425 insertOptionToCollection(StringRef FullName, T &Collection,
426                          const CheckerRegistry::CmdLineOption &Option,
427                          AnalyzerOptions &AnOpts, DiagnosticsEngine &Diags) {
428   auto It = binaryFind(Collection, FullName);
429   assert(It != Collection.end() &&
430          "Failed to find the checker while attempting to add a command line "
431          "option to it!");
432 
433   insertAndValidate(FullName, Option, AnOpts, Diags);
434 
435   It->CmdLineOptions.emplace_back(Option);
436 }
437 
438 void CheckerRegistry::resolveCheckerAndPackageOptions() {
439   for (const std::pair<StringRef, CmdLineOption> &CheckerOptEntry :
440        CheckerOptions) {
441     insertOptionToCollection(CheckerOptEntry.first, Checkers,
442                              CheckerOptEntry.second, AnOpts, Diags);
443   }
444 
445   for (const std::pair<StringRef, CmdLineOption> &PackageOptEntry :
446        PackageOptions) {
447     insertOptionToCollection(PackageOptEntry.first, Packages,
448                              PackageOptEntry.second, AnOpts, Diags);
449   }
450 }
451 
452 void CheckerRegistry::addPackage(StringRef FullName) {
453   Packages.emplace_back(PackageInfo(FullName));
454 }
455 
456 void CheckerRegistry::addPackageOption(StringRef OptionType,
457                                        StringRef PackageFullName,
458                                        StringRef OptionName,
459                                        StringRef DefaultValStr,
460                                        StringRef Description,
461                                        StringRef DevelopmentStatus,
462                                        bool IsHidden) {
463   PackageOptions.emplace_back(
464       PackageFullName, CmdLineOption{OptionType, OptionName, DefaultValStr,
465                                      Description, DevelopmentStatus, IsHidden});
466 }
467 
468 void CheckerRegistry::addChecker(InitializationFunction Rfn,
469                                  ShouldRegisterFunction Sfn, StringRef Name,
470                                  StringRef Desc, StringRef DocsUri,
471                                  bool IsHidden) {
472   Checkers.emplace_back(Rfn, Sfn, Name, Desc, DocsUri, IsHidden);
473 
474   // Record the presence of the checker in its packages.
475   StringRef PackageName, LeafName;
476   std::tie(PackageName, LeafName) = Name.rsplit(PackageSeparator);
477   while (!LeafName.empty()) {
478     PackageSizes[PackageName] += 1;
479     std::tie(PackageName, LeafName) = PackageName.rsplit(PackageSeparator);
480   }
481 }
482 
483 void CheckerRegistry::addCheckerOption(StringRef OptionType,
484                                        StringRef CheckerFullName,
485                                        StringRef OptionName,
486                                        StringRef DefaultValStr,
487                                        StringRef Description,
488                                        StringRef DevelopmentStatus,
489                                        bool IsHidden) {
490   CheckerOptions.emplace_back(
491       CheckerFullName, CmdLineOption{OptionType, OptionName, DefaultValStr,
492                                      Description, DevelopmentStatus, IsHidden});
493 }
494 
495 void CheckerRegistry::initializeManager(CheckerManager &CheckerMgr) const {
496   // Initialize the CheckerManager with all enabled checkers.
497   for (const auto *Checker : EnabledCheckers) {
498     CheckerMgr.setCurrentCheckerName(CheckerNameRef(Checker->FullName));
499     Checker->Initialize(CheckerMgr);
500   }
501 }
502 
503 static void
504 isOptionContainedIn(const CheckerRegistry::CmdLineOptionList &OptionList,
505                     StringRef SuppliedChecker, StringRef SuppliedOption,
506                     const AnalyzerOptions &AnOpts, DiagnosticsEngine &Diags) {
507 
508   if (!AnOpts.ShouldEmitErrorsOnInvalidConfigValue)
509     return;
510 
511   using CmdLineOption = CheckerRegistry::CmdLineOption;
512 
513   auto SameOptName = [SuppliedOption](const CmdLineOption &Opt) {
514     return Opt.OptionName == SuppliedOption;
515   };
516 
517   auto OptionIt = llvm::find_if(OptionList, SameOptName);
518 
519   if (OptionIt == OptionList.end()) {
520     Diags.Report(diag::err_analyzer_checker_option_unknown)
521         << SuppliedChecker << SuppliedOption;
522     return;
523   }
524 }
525 
526 void CheckerRegistry::validateCheckerOptions() const {
527   for (const auto &Config : AnOpts.Config) {
528 
529     StringRef SuppliedCheckerOrPackage;
530     StringRef SuppliedOption;
531     std::tie(SuppliedCheckerOrPackage, SuppliedOption) =
532         Config.getKey().split(':');
533 
534     if (SuppliedOption.empty())
535       continue;
536 
537     // AnalyzerOptions' config table contains the user input, so an entry could
538     // look like this:
539     //
540     //   cor:NoFalsePositives=true
541     //
542     // Since lower_bound would look for the first element *not less* than "cor",
543     // it would return with an iterator to the first checker in the core, so we
544     // we really have to use find here, which uses operator==.
545     auto CheckerIt =
546         llvm::find(Checkers, CheckerInfo(SuppliedCheckerOrPackage));
547     if (CheckerIt != Checkers.end()) {
548       isOptionContainedIn(CheckerIt->CmdLineOptions, SuppliedCheckerOrPackage,
549                           SuppliedOption, AnOpts, Diags);
550       continue;
551     }
552 
553     auto PackageIt =
554         llvm::find(Packages, PackageInfo(SuppliedCheckerOrPackage));
555     if (PackageIt != Packages.end()) {
556       isOptionContainedIn(PackageIt->CmdLineOptions, SuppliedCheckerOrPackage,
557                           SuppliedOption, AnOpts, Diags);
558       continue;
559     }
560 
561     Diags.Report(diag::err_unknown_analyzer_checker_or_package)
562         << SuppliedCheckerOrPackage;
563   }
564 }
565 
566 //===----------------------------------------------------------------------===//
567 // Printing functions.
568 //===----------------------------------------------------------------------===//
569 
570 void CheckerRegistry::printCheckerWithDescList(raw_ostream &Out,
571                                                size_t MaxNameChars) const {
572   // FIXME: Print available packages.
573 
574   Out << "CHECKERS:\n";
575 
576   // Find the maximum option length.
577   size_t OptionFieldWidth = 0;
578   for (const auto &Checker : Checkers) {
579     // Limit the amount of padding we are willing to give up for alignment.
580     //   Package.Name     Description  [Hidden]
581     size_t NameLength = Checker.FullName.size();
582     if (NameLength <= MaxNameChars)
583       OptionFieldWidth = std::max(OptionFieldWidth, NameLength);
584   }
585 
586   const size_t InitialPad = 2;
587 
588   auto Print = [=](llvm::raw_ostream &Out, const CheckerInfo &Checker,
589                    StringRef Description) {
590     AnalyzerOptions::printFormattedEntry(Out, {Checker.FullName, Description},
591                                          InitialPad, OptionFieldWidth);
592     Out << '\n';
593   };
594 
595   for (const auto &Checker : Checkers) {
596     // The order of this if branches is significant, we wouldn't like to display
597     // developer checkers even in the alpha output. For example,
598     // alpha.cplusplus.IteratorModeling is a modeling checker, hence it's hidden
599     // by default, and users (even when the user is a developer of an alpha
600     // checker) shouldn't normally tinker with whether they should be enabled.
601 
602     if (Checker.IsHidden) {
603       if (AnOpts.ShowCheckerHelpDeveloper)
604         Print(Out, Checker, Checker.Desc);
605       continue;
606     }
607 
608     if (Checker.FullName.startswith("alpha")) {
609       if (AnOpts.ShowCheckerHelpAlpha)
610         Print(Out, Checker,
611               ("(Enable only for development!) " + Checker.Desc).str());
612       continue;
613     }
614 
615     if (AnOpts.ShowCheckerHelp)
616         Print(Out, Checker, Checker.Desc);
617   }
618 }
619 
620 void CheckerRegistry::printEnabledCheckerList(raw_ostream &Out) const {
621   for (const auto *i : EnabledCheckers)
622     Out << i->FullName << '\n';
623 }
624 
625 void CheckerRegistry::printCheckerOptionList(raw_ostream &Out) const {
626   Out << "OVERVIEW: Clang Static Analyzer Checker and Package Option List\n\n";
627   Out << "USAGE: -analyzer-config <OPTION1=VALUE,OPTION2=VALUE,...>\n\n";
628   Out << "       -analyzer-config OPTION1=VALUE, -analyzer-config "
629          "OPTION2=VALUE, ...\n\n";
630   Out << "OPTIONS:\n\n";
631 
632   std::multimap<StringRef, const CmdLineOption &> OptionMap;
633 
634   for (const CheckerInfo &Checker : Checkers) {
635     for (const CmdLineOption &Option : Checker.CmdLineOptions) {
636       OptionMap.insert({Checker.FullName, Option});
637     }
638   }
639 
640   for (const PackageInfo &Package : Packages) {
641     for (const CmdLineOption &Option : Package.CmdLineOptions) {
642       OptionMap.insert({Package.FullName, Option});
643     }
644   }
645 
646   auto Print = [] (llvm::raw_ostream &Out, StringRef FullOption, StringRef Desc) {
647     AnalyzerOptions::printFormattedEntry(Out, {FullOption, Desc},
648                                          /*InitialPad*/ 2,
649                                          /*EntryWidth*/ 50,
650                                          /*MinLineWidth*/ 90);
651     Out << "\n\n";
652   };
653   for (const std::pair<const StringRef, const CmdLineOption &> &Entry :
654        OptionMap) {
655     const CmdLineOption &Option = Entry.second;
656     std::string FullOption = (Entry.first + ":" + Option.OptionName).str();
657 
658     std::string Desc =
659         ("(" + Option.OptionType + ") " + Option.Description + " (default: " +
660          (Option.DefaultValStr.empty() ? "\"\"" : Option.DefaultValStr) + ")")
661             .str();
662 
663     // The list of these if branches is significant, we wouldn't like to
664     // display hidden alpha checker options for
665     // -analyzer-checker-option-help-alpha.
666 
667     if (Option.IsHidden) {
668       if (AnOpts.ShowCheckerOptionDeveloperList)
669         Print(Out, FullOption, Desc);
670       continue;
671     }
672 
673     if (Option.DevelopmentStatus == "alpha" ||
674         Entry.first.startswith("alpha")) {
675       if (AnOpts.ShowCheckerOptionAlphaList)
676         Print(Out, FullOption,
677               llvm::Twine("(Enable only for development!) " + Desc).str());
678       continue;
679     }
680 
681     if (AnOpts.ShowCheckerOptionList)
682       Print(Out, FullOption, Desc);
683   }
684 }
685