f964e8a3f9
Add an option to the `bugprone-implicit-widening-of-multiplication-result` clang-tidy checker to suppress warnings when the expression is made up of all compile-time constants (literals, `constexpr` values or results, etc.) and the result of the multiplication is guaranteed to fit in both the source and destination types. This currently only works for signed integer types: * For unsigned integers, the well-defined rollover behavior on overflow prevents the checker from detecting that the expression does not actually fit in the source expr type, and would produce false negatives. I have a somewhat-hacky stab at addressing this I'd like to submit as a follow-on PR * For floating-point types, there's probably a little additional work to be done to `Expr` to calculate the result at compile time Even still, this seems like a helpful addition just for signed types, and additional types can be added.
51 lines
2.0 KiB
C++
51 lines
2.0 KiB
C++
//===--- ImplicitWideningOfMultiplicationResultCheck.h ----------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_IMPLICITWIDENINGOFMULTIPLICATIONRESULTCHECK_H
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#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_IMPLICITWIDENINGOFMULTIPLICATIONRESULTCHECK_H
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#include "../ClangTidyCheck.h"
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#include "../utils/IncludeInserter.h"
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#include <optional>
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namespace clang::tidy::bugprone {
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/// Diagnoses instances of an implicit widening of multiplication result.
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///
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/// For the user-facing documentation see:
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/// http://clang.llvm.org/extra/clang-tidy/checks/bugprone/implicit-widening-of-multiplication-result.html
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class ImplicitWideningOfMultiplicationResultCheck : public ClangTidyCheck {
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const ast_matchers::MatchFinder::MatchResult *Result;
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bool ShouldUseCXXStaticCast;
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bool ShouldUseCXXHeader;
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std::optional<FixItHint> includeStddefHeader(SourceLocation File);
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void handleImplicitCastExpr(const ImplicitCastExpr *ICE);
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void handlePointerOffsetting(const Expr *E);
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public:
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ImplicitWideningOfMultiplicationResultCheck(StringRef Name,
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ClangTidyContext *Context);
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void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP,
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Preprocessor *ModuleExpanderPP) override;
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void registerMatchers(ast_matchers::MatchFinder *Finder) override;
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void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
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void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
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private:
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const bool UseCXXStaticCastsInCppSources;
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const bool UseCXXHeadersInCppSources;
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const bool IgnoreConstantIntExpr;
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utils::IncludeInserter IncludeInserter;
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};
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} // namespace clang::tidy::bugprone
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#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_IMPLICITWIDENINGOFMULTIPLICATIONRESULTCHECK_H
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