[clang-tools-extra] [clang-tidy] Add performance-bool-bitwise-operation check (PR #142324)
Baranov Victor via cfe-commits
cfe-commits at lists.llvm.org
Mon Jun 2 05:08:39 PDT 2025
================
@@ -0,0 +1,200 @@
+//===--- BoolBitwiseOperationCheck.cpp - clang-tidy -----------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "BoolBitwiseOperationCheck.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Lex/Lexer.h"
+#include <array>
+#include <optional>
+#include <utility>
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::performance {
+namespace {
+bool hasExplicitParentheses(const Expr *E, const SourceManager &SM,
+ const LangOptions &LangOpts) {
+ if (!E)
+ return false;
+
+ const SourceLocation Start = E->getBeginLoc();
+ const SourceLocation End = E->getEndLoc();
+
+ if (Start.isMacroID() || End.isMacroID() || !Start.isValid() ||
+ !End.isValid()) {
+ return false;
+ }
+
+ const std::optional<Token> PrevTok =
+ Lexer::findPreviousToken(Start, SM, LangOpts, /*IncludeComments=*/false);
+ const std::optional<Token> NextTok =
+ Lexer::findNextToken(End, SM, LangOpts, /*IncludeComments=*/false);
+
+ return (PrevTok && PrevTok->is(tok::l_paren)) &&
+ (NextTok && NextTok->is(tok::r_paren));
+}
+
+template <typename AstNode>
+bool isInTemplateFunction(const AstNode *AN, ASTContext &Context) {
+ auto Parents = Context.getParents(*AN);
+ for (const auto &Parent : Parents) {
+ if (const auto *FD = Parent.template get<FunctionDecl>()) {
+ return FD->isTemplateInstantiation() ||
+ FD->getTemplatedKind() != FunctionDecl::TK_NonTemplate;
+ }
+ if (const auto *S = Parent.template get<Stmt>()) {
+ return isInTemplateFunction(S, Context);
+ }
+ }
+ return false;
+}
+
+constexpr std::array<std::pair<llvm::StringRef, llvm::StringRef>, 8U>
+ OperatorsTransformation{{{"|", "||"},
+ {"|=", "||"},
+ {"&", "&&"},
+ {"&=", "&&"},
+ {"bitand", "and"},
+ {"and_eq", "and"},
+ {"bitor", "or"},
+ {"or_eq", "or"}}};
+
+llvm::StringRef translate(llvm::StringRef Value) {
+ for (const auto &[Bitwise, Logical] : OperatorsTransformation) {
+ if (Value == Bitwise)
+ return Logical;
+ }
+
+ return {};
+}
+} // namespace
+
+BoolBitwiseOperationCheck::BoolBitwiseOperationCheck(StringRef Name,
+ ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context), ChangePossibleSideEffects(Options.get(
+ "ChangePossibleSideEffects", false)) {}
+
+void BoolBitwiseOperationCheck::storeOptions(
+ ClangTidyOptions::OptionMap &Opts) {
+ Options.store(Opts, "ChangePossibleSideEffects", ChangePossibleSideEffects);
+}
+
+void BoolBitwiseOperationCheck::registerMatchers(MatchFinder *Finder) {
+ Finder->addMatcher(
+ binaryOperator(
+ unless(isExpansionInSystemHeader()),
+ hasAnyOperatorName("|", "&", "|=", "&="),
+ hasEitherOperand(expr(ignoringImpCasts(hasType(booleanType())))),
+ optionally(hasAncestor( // to simple implement transformations like
+ // `a&&b|c` -> `a&&(b||c)`
+ binaryOperator().bind("p"))))
+ .bind("op"),
+ this);
+}
+
+void BoolBitwiseOperationCheck::check(const MatchFinder::MatchResult &Result) {
+ const auto *MatchedExpr = Result.Nodes.getNodeAs<BinaryOperator>("op");
+
+ auto Diag = diag(MatchedExpr->getOperatorLoc(),
+ "use logical operator instead of bitwise one for bool");
----------------
vbvictor wrote:
This message should be more detailed about what particular operator should be used.
Here is an example of my vision:
```cpp
bool invalid = false;
invalid |= x > limit.x; // warning: use logical operator '||' for boolean variable 'invalid' instead of bitwise operator '|='
```
This clarification is useful when a user only read warning messages from clang-tidy, so they must be unambiguous.
https://github.com/llvm/llvm-project/pull/142324
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