clang-tools  15.0.0git
DeleteNullPointerCheck.cpp
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1 //===--- DeleteNullPointerCheck.cpp - clang-tidy---------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
10 #include "../utils/LexerUtils.h"
11 #include "clang/AST/ASTContext.h"
12 #include "clang/ASTMatchers/ASTMatchFinder.h"
13 #include "clang/Lex/Lexer.h"
14 
15 using namespace clang::ast_matchers;
16 
17 namespace clang {
18 namespace tidy {
19 namespace readability {
20 
21 void DeleteNullPointerCheck::registerMatchers(MatchFinder *Finder) {
22  const auto DeleteExpr =
23  cxxDeleteExpr(
24  has(declRefExpr(to(decl(equalsBoundNode("deletedPointer"))))))
25  .bind("deleteExpr");
26 
27  const auto DeleteMemberExpr =
28  cxxDeleteExpr(has(memberExpr(hasDeclaration(
29  fieldDecl(equalsBoundNode("deletedMemberPointer"))))))
30  .bind("deleteMemberExpr");
31 
32  const auto PointerExpr = anyOf(
33  declRefExpr(to(decl().bind("deletedPointer"))),
34  memberExpr(hasDeclaration(fieldDecl().bind("deletedMemberPointer"))));
35 
36  const auto BinaryPointerCheckCondition = binaryOperator(hasOperands(
37  anyOf(cxxNullPtrLiteralExpr(), integerLiteral(equals(0))), PointerExpr));
38 
39  Finder->addMatcher(
40  ifStmt(hasCondition(anyOf(PointerExpr, BinaryPointerCheckCondition)),
41  hasThen(anyOf(
42  DeleteExpr, DeleteMemberExpr,
43  compoundStmt(anyOf(has(DeleteExpr), has(DeleteMemberExpr)),
44  statementCountIs(1))
45  .bind("compound"))))
46  .bind("ifWithDelete"),
47  this);
48 }
49 
50 void DeleteNullPointerCheck::check(const MatchFinder::MatchResult &Result) {
51  const auto *IfWithDelete = Result.Nodes.getNodeAs<IfStmt>("ifWithDelete");
52  const auto *Compound = Result.Nodes.getNodeAs<CompoundStmt>("compound");
53 
54  auto Diag = diag(
55  IfWithDelete->getBeginLoc(),
56  "'if' statement is unnecessary; deleting null pointer has no effect");
57  if (IfWithDelete->getElse())
58  return;
59  // FIXME: generate fixit for this case.
60 
61  Diag << FixItHint::CreateRemoval(CharSourceRange::getTokenRange(
62  IfWithDelete->getBeginLoc(),
63  utils::lexer::getPreviousToken(IfWithDelete->getThen()->getBeginLoc(),
64  *Result.SourceManager,
65  Result.Context->getLangOpts())
66  .getLocation()));
67 
68  if (Compound) {
69  Diag << FixItHint::CreateRemoval(
70  CharSourceRange::getTokenRange(Compound->getLBracLoc()));
71  Diag << FixItHint::CreateRemoval(
72  CharSourceRange::getTokenRange(Compound->getRBracLoc()));
73  }
74 }
75 
76 } // namespace readability
77 } // namespace tidy
78 } // namespace clang
clang::clangd::check
bool check(llvm::StringRef File, llvm::Optional< Range > LineRange, const ThreadsafeFS &TFS, const ClangdLSPServer::Options &Opts, bool EnableCodeCompletion)
Definition: Check.cpp:273
clang::ast_matchers
Definition: AbseilMatcher.h:14
clang::tidy::utils::lexer::getPreviousToken
Token getPreviousToken(SourceLocation Location, const SourceManager &SM, const LangOptions &LangOpts, bool SkipComments)
Returns previous token or tok::unknown if not found.
Definition: LexerUtils.cpp:18
DeleteNullPointerCheck.h
clang
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ApplyReplacements.h:27