83 lines
3.1 KiB
C++
83 lines
3.1 KiB
C++
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//===--- IncDecInConditionsCheck.cpp - clang-tidy -------------------------===//
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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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#include "IncDecInConditionsCheck.h"
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#include "../utils/Matchers.h"
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#include "clang/AST/ASTContext.h"
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#include "clang/ASTMatchers/ASTMatchFinder.h"
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using namespace clang::ast_matchers;
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namespace clang::tidy::bugprone {
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AST_MATCHER(BinaryOperator, isLogicalOperator) { return Node.isLogicalOp(); }
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AST_MATCHER(UnaryOperator, isUnaryPrePostOperator) {
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return Node.isPrefix() || Node.isPostfix();
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}
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AST_MATCHER(CXXOperatorCallExpr, isPrePostOperator) {
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return Node.getOperator() == OO_PlusPlus ||
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Node.getOperator() == OO_MinusMinus;
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}
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void IncDecInConditionsCheck::registerMatchers(MatchFinder *Finder) {
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auto OperatorMatcher = expr(
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anyOf(binaryOperator(anyOf(isComparisonOperator(), isLogicalOperator())),
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cxxOperatorCallExpr(isComparisonOperator())));
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Finder->addMatcher(
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expr(
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OperatorMatcher, unless(isExpansionInSystemHeader()),
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unless(hasAncestor(OperatorMatcher)), expr().bind("parent"),
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forEachDescendant(
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expr(anyOf(unaryOperator(isUnaryPrePostOperator(),
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hasUnaryOperand(expr().bind("operand"))),
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cxxOperatorCallExpr(
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isPrePostOperator(),
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hasUnaryOperand(expr().bind("operand")))),
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hasAncestor(
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expr(equalsBoundNode("parent"),
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hasDescendant(
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expr(unless(equalsBoundNode("operand")),
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matchers::isStatementIdenticalToBoundNode(
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"operand"))
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.bind("second")))))
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.bind("operator"))),
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this);
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}
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void IncDecInConditionsCheck::check(const MatchFinder::MatchResult &Result) {
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SourceLocation ExprLoc;
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bool IsIncrementOp = false;
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if (const auto *MatchedDecl =
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Result.Nodes.getNodeAs<CXXOperatorCallExpr>("operator")) {
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ExprLoc = MatchedDecl->getExprLoc();
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IsIncrementOp = (MatchedDecl->getOperator() == OO_PlusPlus);
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} else if (const auto *MatchedDecl =
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Result.Nodes.getNodeAs<UnaryOperator>("operator")) {
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ExprLoc = MatchedDecl->getExprLoc();
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IsIncrementOp = MatchedDecl->isIncrementOp();
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} else
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return;
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diag(ExprLoc,
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"%select{decrementing|incrementing}0 and referencing a variable in a "
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"complex condition can cause unintended side-effects due to C++'s order "
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"of evaluation, consider moving the modification outside of the "
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"condition to avoid misunderstandings")
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<< IsIncrementOp;
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diag(Result.Nodes.getNodeAs<Expr>("second")->getExprLoc(),
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"variable is referenced here", DiagnosticIDs::Note);
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}
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} // namespace clang::tidy::bugprone
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