| 1 | //===--- DeleteNullPointerCheck.cpp - clang-tidy---------------------------===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | |
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| 9 | #include "DeleteNullPointerCheck.h" |
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| 10 | #include "../utils/LexerUtils.h" |
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| 11 | #include "clang/AST/ASTContext.h" |
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| 12 | #include "clang/ASTMatchers/ASTMatchFinder.h" |
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| 13 | #include "clang/Lex/Lexer.h" |
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| 14 | |
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| 15 | using namespace clang::ast_matchers; |
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| 16 | |
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| 17 | namespace clang::tidy::readability { |
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| 18 | |
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| 19 | void DeleteNullPointerCheck::registerMatchers(MatchFinder *Finder) { |
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| 20 | const auto DeleteExpr = |
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| 21 | cxxDeleteExpr( |
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| 22 | has(declRefExpr(to(InnerMatcher: decl(equalsBoundNode(ID: "deletedPointer" )))))) |
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| 23 | .bind(ID: "deleteExpr" ); |
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| 24 | |
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| 25 | const auto DeleteMemberExpr = |
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| 26 | cxxDeleteExpr(has(memberExpr(hasDeclaration( |
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| 27 | InnerMatcher: fieldDecl(equalsBoundNode(ID: "deletedMemberPointer" )))))) |
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| 28 | .bind(ID: "deleteMemberExpr" ); |
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| 29 | |
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| 30 | const auto PointerExpr = anyOf( |
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| 31 | declRefExpr(to(InnerMatcher: decl().bind(ID: "deletedPointer" ))), |
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| 32 | memberExpr(hasDeclaration(InnerMatcher: fieldDecl().bind(ID: "deletedMemberPointer" )))); |
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| 33 | |
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| 34 | const auto BinaryPointerCheckCondition = binaryOperator(hasOperands( |
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| 35 | Matcher1: anyOf(cxxNullPtrLiteralExpr(), integerLiteral(equals(Value: 0))), Matcher2: PointerExpr)); |
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| 36 | |
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| 37 | Finder->addMatcher( |
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| 38 | NodeMatch: ifStmt(hasCondition(InnerMatcher: anyOf(PointerExpr, BinaryPointerCheckCondition)), |
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| 39 | hasThen(InnerMatcher: anyOf( |
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| 40 | DeleteExpr, DeleteMemberExpr, |
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| 41 | compoundStmt(anyOf(has(DeleteExpr), has(DeleteMemberExpr)), |
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| 42 | statementCountIs(N: 1)) |
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| 43 | .bind(ID: "compound" )))) |
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| 44 | .bind(ID: "ifWithDelete" ), |
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| 45 | Action: this); |
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| 46 | } |
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| 47 | |
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| 48 | void DeleteNullPointerCheck::check(const MatchFinder::MatchResult &Result) { |
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| 49 | const auto *IfWithDelete = Result.Nodes.getNodeAs<IfStmt>(ID: "ifWithDelete" ); |
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| 50 | const auto *Compound = Result.Nodes.getNodeAs<CompoundStmt>(ID: "compound" ); |
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| 51 | |
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| 52 | auto Diag = diag( |
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| 53 | Loc: IfWithDelete->getBeginLoc(), |
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| 54 | Description: "'if' statement is unnecessary; deleting null pointer has no effect" ); |
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| 55 | if (IfWithDelete->getElse()) |
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| 56 | return; |
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| 57 | // FIXME: generate fixit for this case. |
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| 58 | |
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| 59 | Diag << FixItHint::CreateRemoval(RemoveRange: CharSourceRange::getTokenRange( |
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| 60 | B: IfWithDelete->getBeginLoc(), |
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| 61 | E: utils::lexer::getPreviousToken(Location: IfWithDelete->getThen()->getBeginLoc(), |
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| 62 | SM: *Result.SourceManager, |
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| 63 | LangOpts: Result.Context->getLangOpts()) |
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| 64 | .getLocation())); |
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| 65 | |
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| 66 | if (Compound) { |
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| 67 | Diag << FixItHint::CreateRemoval( |
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| 68 | RemoveRange: CharSourceRange::getTokenRange(R: Compound->getLBracLoc())); |
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| 69 | Diag << FixItHint::CreateRemoval( |
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| 70 | RemoveRange: CharSourceRange::getTokenRange(R: Compound->getRBracLoc())); |
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| 71 | } |
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| 72 | } |
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| 73 | |
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| 74 | } // namespace clang::tidy::readability |
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| 75 | |
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