clang-tidy/readability/MagicNumbersCheck.h

0001 //===--- MagicNumbersCheck.h - clang-tidy-----------------------*- C++ -*-===//
0002 //
0003 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0004 // See https://llvm.org/LICENSE.txt for license information.
0005 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0006 //
0007 //===----------------------------------------------------------------------===//
0008
0009 #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_MAGICNUMBERSCHECK_H
0010 #define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_MAGICNUMBERSCHECK_H
0011
0012 #include "../ClangTidyCheck.h"
0013 #include "clang/Lex/Lexer.h"
0014 #include <llvm/ADT/APFloat.h>
0015 #include <llvm/ADT/SmallVector.h>
0016
0017 namespace clang::tidy::readability {
0018
0019 /// Detects magic numbers, integer and floating point literals embedded in code.
0020 ///
0021 /// For the user-facing documentation see:
0022 /// http://clang.llvm.org/extra/clang-tidy/checks/readability/magic-numbers.html
0023 class MagicNumbersCheck : public ClangTidyCheck {
0024 public:
0025   MagicNumbersCheck(StringRef Name, ClangTidyContext *Context);
0026   void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
0027   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
0028   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
0029
0030 private:
0031   bool isConstant(const clang::ast_matchers::MatchFinder::MatchResult &Result,
0032                   const clang::Expr &ExprResult) const;
0033
0034   bool isIgnoredValue(const IntegerLiteral *Literal) const;
0035   bool isIgnoredValue(const FloatingLiteral *Literal) const;
0036
0037   bool isSyntheticValue(const clang::SourceManager *,
0038                         const FloatingLiteral *) const {
0039     return false;
0040   }
0041   bool isSyntheticValue(const clang::SourceManager *SourceManager,
0042                         const IntegerLiteral *Literal) const;
0043
0044   bool isBitFieldWidth(const clang::ast_matchers::MatchFinder::MatchResult &,
0045                        const FloatingLiteral &) const {
0046      return false;
0047   }
0048
0049   bool isBitFieldWidth(const clang::ast_matchers::MatchFinder::MatchResult &Result,
0050                        const IntegerLiteral &Literal) const;
0051
0052   bool isUserDefinedLiteral(
0053       const clang::ast_matchers::MatchFinder::MatchResult &Result,
0054       const clang::Expr &Literal) const;
0055
0056   template <typename L>
0057   void checkBoundMatch(const ast_matchers::MatchFinder::MatchResult &Result,
0058                        const char *BoundName) {
0059     const L *MatchedLiteral = Result.Nodes.getNodeAs<L>(BoundName);
0060     if (!MatchedLiteral)
0061       return;
0062
0063     if (Result.SourceManager->isMacroBodyExpansion(
0064             MatchedLiteral->getLocation()))
0065       return;
0066
0067     if (isIgnoredValue(MatchedLiteral))
0068       return;
0069
0070     if (isConstant(Result, *MatchedLiteral))
0071       return;
0072
0073     if (isSyntheticValue(Result.SourceManager, MatchedLiteral))
0074       return;
0075
0076     if (isBitFieldWidth(Result, *MatchedLiteral))
0077       return;
0078
0079     if (IgnoreUserDefinedLiterals &&
0080         isUserDefinedLiteral(Result, *MatchedLiteral))
0081       return;
0082
0083     const StringRef LiteralSourceText = Lexer::getSourceText(
0084         CharSourceRange::getTokenRange(MatchedLiteral->getSourceRange()),
0085         *Result.SourceManager, getLangOpts());
0086
0087     diag(MatchedLiteral->getLocation(),
0088          "%0 is a magic number; consider replacing it with a named constant")
0089         << LiteralSourceText;
0090   }
0091
0092   const bool IgnoreAllFloatingPointValues;
0093   const bool IgnoreBitFieldsWidths;
0094   const bool IgnorePowersOf2IntegerValues;
0095   const bool IgnoreTypeAliases;
0096   const bool IgnoreUserDefinedLiterals;
0097   const StringRef RawIgnoredIntegerValues;
0098   const StringRef RawIgnoredFloatingPointValues;
0099
0100   constexpr static unsigned SensibleNumberOfMagicValueExceptions = 16;
0101
0102   constexpr static llvm::APFloat::roundingMode DefaultRoundingMode =
0103       llvm::APFloat::rmNearestTiesToEven;
0104
0105   llvm::SmallVector<int64_t, SensibleNumberOfMagicValueExceptions>
0106       IgnoredIntegerValues;
0107   llvm::SmallVector<float, SensibleNumberOfMagicValueExceptions>
0108       IgnoredFloatingPointValues;
0109   llvm::SmallVector<double, SensibleNumberOfMagicValueExceptions>
0110       IgnoredDoublePointValues;
0111 };
0112
0113 } // namespace clang::tidy::readability
0114
0115 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_MAGICNUMBERSCHECK_H