clang-tools-extra/clang-tidy/utils/TransformerClangTidyCheck.cpp

   1 //===---------- TransformerClangTidyCheck.cpp - 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 "TransformerClangTidyCheck.h"
  10 #include "clang/Basic/DiagnosticIDs.h"
  11 #include "clang/Lex/Preprocessor.h"
  12 #include "llvm/ADT/STLExtras.h"
  13 #include <optional>
  14
  15 namespace clang::tidy::utils {
  16 using transformer::RewriteRuleWith;
  17
  18 #ifndef NDEBUG
  19 static bool hasGenerator(const transformer::Generator<std::string> &G) {
  20   return G != nullptr;
  21 }
  22 #endif
  23
  24 static void verifyRule(const RewriteRuleWith<std::string> &Rule) {
  25   assert(llvm::all_of(Rule.Metadata, hasGenerator) &&
  26          "clang-tidy checks must have an explanation by default;"
  27          " explicitly provide an empty explanation if none is desired");
  28 }
  29
  30 // If a string unintentionally containing '%' is passed as a diagnostic, Clang
  31 // will claim the string is ill-formed and assert-fail. This function escapes
  32 // such strings so they can be safely used in diagnostics.
  33 std::string escapeForDiagnostic(std::string ToEscape) {
  34   // Optimize for the common case that the string does not contain `%` at the
  35   // cost of an extra scan over the string in the slow case.
  36   auto Pos = ToEscape.find('%');
  37   if (Pos == ToEscape.npos)
  38     return ToEscape;
  39
  40   std::string Result;
  41   Result.reserve(ToEscape.size());
  42   // Convert position to a count.
  43   ++Pos;
  44   Result.append(ToEscape, 0, Pos);
  45   Result += '%';
  46
  47   for (auto N = ToEscape.size(); Pos < N; ++Pos) {
  48     const char C = ToEscape.at(Pos);
  49     Result += C;
  50     if (C == '%')
  51       Result += '%';
  52   }
  53
  54   return Result;
  55 }
  56
  57 TransformerClangTidyCheck::TransformerClangTidyCheck(StringRef Name,
  58                                                      ClangTidyContext *Context)
  59     : ClangTidyCheck(Name, Context),
  60       Inserter(Options.getLocalOrGlobal("IncludeStyle", IncludeSorter::IS_LLVM),
  61                areDiagsSelfContained()) {}
  62
  63 // This constructor cannot dispatch to the simpler one (below), because, in
  64 // order to get meaningful results from `getLangOpts` and `Options`, we need the
  65 // `ClangTidyCheck()` constructor to have been called. If we were to dispatch,
  66 // we would be accessing `getLangOpts` and `Options` before the underlying
  67 // `ClangTidyCheck` instance was properly initialized.
  68 TransformerClangTidyCheck::TransformerClangTidyCheck(
  69     std::function<std::optional<RewriteRuleWith<std::string>>(
  70         const LangOptions &, const OptionsView &)>
  71         MakeRule,
  72     StringRef Name, ClangTidyContext *Context)
  73     : TransformerClangTidyCheck(Name, Context) {
  74   if (std::optional<RewriteRuleWith<std::string>> R =
  75           MakeRule(getLangOpts(), Options))
  76     setRule(std::move(*R));
  77 }
  78
  79 TransformerClangTidyCheck::TransformerClangTidyCheck(
  80     RewriteRuleWith<std::string> R, StringRef Name, ClangTidyContext *Context)
  81     : TransformerClangTidyCheck(Name, Context) {
  82   setRule(std::move(R));
  83 }
  84
  85 void TransformerClangTidyCheck::setRule(
  86     transformer::RewriteRuleWith<std::string> R) {
  87   verifyRule(R);
  88   Rule = std::move(R);
  89 }
  90
  91 void TransformerClangTidyCheck::registerPPCallbacks(
  92     const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) {
  93   Inserter.registerPreprocessor(PP);
  94 }
  95
  96 void TransformerClangTidyCheck::registerMatchers(
  97     ast_matchers::MatchFinder *Finder) {
  98   if (!Rule.Cases.empty())
  99     for (auto &Matcher : transformer::detail::buildMatchers(Rule))
 100       Finder->addDynamicMatcher(Matcher, this);
 101 }
 102
 103 void TransformerClangTidyCheck::check(
 104     const ast_matchers::MatchFinder::MatchResult &Result) {
 105   if (Result.Context->getDiagnostics().hasErrorOccurred())
 106     return;
 107
 108   size_t I = transformer::detail::findSelectedCase(Result, Rule);
 109   Expected<SmallVector<transformer::Edit, 1>> Edits =
 110       Rule.Cases[I].Edits(Result);
 111   if (!Edits) {
 112     llvm::errs() << "Rewrite failed: " << llvm::toString(Edits.takeError())
 113                  << "\n";
 114     return;
 115   }
 116
 117   // No rewrite applied, but no error encountered either.
 118   if (Edits->empty())
 119     return;
 120
 121   Expected<std::string> Explanation = Rule.Metadata[I]->eval(Result);
 122   if (!Explanation) {
 123     llvm::errs() << "Error in explanation: "
 124                  << llvm::toString(Explanation.takeError()) << "\n";
 125     return;
 126   }
 127
 128   // Associate the diagnostic with the location of the first change.
 129   {
 130     DiagnosticBuilder Diag =
 131         diag((*Edits)[0].Range.getBegin(), escapeForDiagnostic(*Explanation));
 132     for (const auto &T : *Edits) {
 133       switch (T.Kind) {
 134       case transformer::EditKind::Range:
 135         Diag << FixItHint::CreateReplacement(T.Range, T.Replacement);
 136         break;
 137       case transformer::EditKind::AddInclude:
 138         Diag << Inserter.createIncludeInsertion(
 139             Result.SourceManager->getFileID(T.Range.getBegin()), T.Replacement);
 140         break;
 141       }
 142     }
 143   }
 144   // Emit potential notes.
 145   for (const auto &T : *Edits) {
 146     if (!T.Note.empty()) {
 147       diag(T.Range.getBegin(), escapeForDiagnostic(T.Note),
 148            DiagnosticIDs::Note);
 149     }
 150   }
 151 }
 152
 153 void TransformerClangTidyCheck::storeOptions(
 154     ClangTidyOptions::OptionMap &Opts) {
 155   Options.store(Opts, "IncludeStyle", Inserter.getStyle());
 156 }
 157
 158 } // namespace clang::tidy::utils