clang-tools 19.0.0git
BoolPointerImplicitConversionCheck.cpp
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1//===--- BoolPointerImplicitConversionCheck.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
11using namespace clang::ast_matchers;
12
13namespace clang::tidy::bugprone {
14
16 // Look for ifs that have an implicit bool* to bool conversion in the
17 // condition. Filter negations.
18 Finder->addMatcher(
19 traverse(
20 TK_AsIs,
21 ifStmt(
22 hasCondition(findAll(implicitCastExpr(
23 unless(hasParent(unaryOperator(hasOperatorName("!")))),
24 hasSourceExpression(expr(
25 hasType(pointerType(pointee(booleanType()))),
26 ignoringParenImpCasts(anyOf(declRefExpr().bind("expr"),
27 memberExpr().bind("expr"))))),
28 hasCastKind(CK_PointerToBoolean)))),
29 unless(isInTemplateInstantiation()))
30 .bind("if")),
31 this);
32}
33
34static void checkImpl(const MatchFinder::MatchResult &Result, const Expr *Ref,
35 const IfStmt *If,
36 const ast_matchers::internal::Matcher<Expr> &RefMatcher,
37 ClangTidyCheck &Check) {
38 // Ignore macros.
39 if (Ref->getBeginLoc().isMacroID())
40 return;
41
42 // Only allow variable accesses and member exprs for now, no function calls.
43 // Check that we don't dereference the variable anywhere within the if. This
44 // avoids false positives for checks of the pointer for nullptr before it is
45 // dereferenced. If there is a dereferencing operator on this variable don't
46 // emit a diagnostic. Also ignore array subscripts.
47 if (!match(findAll(unaryOperator(hasOperatorName("*"),
48 hasUnaryOperand(RefMatcher))),
49 *If, *Result.Context)
50 .empty() ||
51 !match(findAll(arraySubscriptExpr(hasBase(RefMatcher))), *If,
52 *Result.Context)
53 .empty() ||
54 // FIXME: We should still warn if the paremater is implicitly converted to
55 // bool.
56 !match(
57 findAll(callExpr(hasAnyArgument(ignoringParenImpCasts(RefMatcher)))),
58 *If, *Result.Context)
59 .empty() ||
60 !match(
61 findAll(cxxDeleteExpr(has(ignoringParenImpCasts(expr(RefMatcher))))),
62 *If, *Result.Context)
63 .empty())
64 return;
65
66 Check.diag(Ref->getBeginLoc(),
67 "dubious check of 'bool *' against 'nullptr', did "
68 "you mean to dereference it?")
69 << FixItHint::CreateInsertion(Ref->getBeginLoc(), "*");
70}
71
73 const MatchFinder::MatchResult &Result) {
74 const auto *If = Result.Nodes.getNodeAs<IfStmt>("if");
75 if (const auto *E = Result.Nodes.getNodeAs<Expr>("expr")) {
76 const Decl *D = isa<DeclRefExpr>(E) ? cast<DeclRefExpr>(E)->getDecl()
77 : cast<MemberExpr>(E)->getMemberDecl();
78 const auto M =
79 ignoringParenImpCasts(anyOf(declRefExpr(to(equalsNode(D))),
80 memberExpr(hasDeclaration(equalsNode(D)))));
81 checkImpl(Result, E, If, M, *this);
82 }
83}
84
85} // namespace clang::tidy::bugprone
const Expr * E
const FunctionDecl * Decl
const google::protobuf::Message & M
Definition: Server.cpp:309
Base class for all clang-tidy checks.
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.
void check(const ast_matchers::MatchFinder::MatchResult &Result) override
ClangTidyChecks that register ASTMatchers should do the actual work in here.
static void checkImpl(const MatchFinder::MatchResult &Result, const Expr *Ref, const IfStmt *If, const ast_matchers::internal::Matcher< Expr > &RefMatcher, ClangTidyCheck &Check)