clang-tools  10.0.0
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 
11 using namespace clang::ast_matchers;
12 
13 namespace clang {
14 namespace tidy {
15 namespace bugprone {
16 
17 void BoolPointerImplicitConversionCheck::registerMatchers(MatchFinder *Finder) {
18  // Look for ifs that have an implicit bool* to bool conversion in the
19  // condition. Filter negations.
20  Finder->addMatcher(
21  ifStmt(hasCondition(findAll(implicitCastExpr(
22  unless(hasParent(unaryOperator(hasOperatorName("!")))),
23  hasSourceExpression(
24  expr(hasType(pointerType(pointee(booleanType()))),
25  ignoringParenImpCasts(declRefExpr().bind("expr")))),
26  hasCastKind(CK_PointerToBoolean)))),
27  unless(isInTemplateInstantiation()))
28  .bind("if"),
29  this);
30 }
31 
32 void BoolPointerImplicitConversionCheck::check(
33  const MatchFinder::MatchResult &Result) {
34  auto *If = Result.Nodes.getNodeAs<IfStmt>("if");
35  auto *Var = Result.Nodes.getNodeAs<DeclRefExpr>("expr");
36 
37  // Ignore macros.
38  if (Var->getBeginLoc().isMacroID())
39  return;
40 
41  // Only allow variable accesses for now, no function calls or member exprs.
42  // Check that we don't dereference the variable anywhere within the if. This
43  // avoids false positives for checks of the pointer for nullptr before it is
44  // dereferenced. If there is a dereferencing operator on this variable don't
45  // emit a diagnostic. Also ignore array subscripts.
46  const Decl *D = Var->getDecl();
47  auto DeclRef = ignoringParenImpCasts(declRefExpr(to(equalsNode(D))));
48  if (!match(findAll(
49  unaryOperator(hasOperatorName("*"), hasUnaryOperand(DeclRef))),
50  *If, *Result.Context)
51  .empty() ||
52  !match(findAll(arraySubscriptExpr(hasBase(DeclRef))), *If,
53  *Result.Context)
54  .empty() ||
55  // FIXME: We should still warn if the paremater is implicitly converted to
56  // bool.
57  !match(findAll(callExpr(hasAnyArgument(ignoringParenImpCasts(DeclRef)))),
58  *If, *Result.Context)
59  .empty() ||
60  !match(findAll(cxxDeleteExpr(has(ignoringParenImpCasts(expr(DeclRef))))),
61  *If, *Result.Context)
62  .empty())
63  return;
64 
65  diag(Var->getBeginLoc(), "dubious check of 'bool *' against 'nullptr', did "
66  "you mean to dereference it?")
67  << FixItHint::CreateInsertion(Var->getBeginLoc(), "*");
68 }
69 
70 } // namespace bugprone
71 } // namespace tidy
72 } // namespace clang
const FunctionDecl * Decl
std::vector< std::string > match(const SymbolIndex &I, const FuzzyFindRequest &Req, bool *Incomplete)
Definition: TestIndex.cpp:94
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
const DeclRefExpr * DeclRef