clang-tools 6.0.0

BoolPointerImplicitConversionCheck.cpp
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1 //===--- BoolPointerImplicitConversionCheck.cpp - clang-tidy --------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9
10 #include "BoolPointerImplicitConversionCheck.h"
11
12 using namespace clang::ast_matchers;
13
14 namespace clang {
15 namespace tidy {
16 namespace bugprone {
17
18 void BoolPointerImplicitConversionCheck::registerMatchers(MatchFinder *Finder) {
19 // Look for ifs that have an implicit bool* to bool conversion in the
20 // condition. Filter negations.
21 Finder->addMatcher(
22 ifStmt(hasCondition(findAll(implicitCastExpr(
23 allOf(unless(hasParent(unaryOperator(hasOperatorName("!")))),
24 hasSourceExpression(expr(
25 hasType(pointerType(pointee(booleanType()))),
26 ignoringParenImpCasts(declRefExpr().bind("expr")))),
27 hasCastKind(CK_PointerToBoolean))))),
28 unless(isInTemplateInstantiation()))
29 .bind("if"),
30 this);
31 }
32
33 void BoolPointerImplicitConversionCheck::check(
34 const MatchFinder::MatchResult &Result) {
35 auto *If = Result.Nodes.getNodeAs<IfStmt>("if");
36 auto *Var = Result.Nodes.getNodeAs<DeclRefExpr>("expr");
37
38 // Ignore macros.
39 if (Var->getLocStart().isMacroID())
40 return;
41
42 // Only allow variable accesses for now, no function calls or member exprs.
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 const Decl *D = Var->getDecl();
48 auto DeclRef = ignoringParenImpCasts(declRefExpr(to(equalsNode(D))));
49 if (!match(findAll(
50 unaryOperator(hasOperatorName("*"), hasUnaryOperand(DeclRef))),
51 *If, *Result.Context)
52 .empty() ||
53 !match(findAll(arraySubscriptExpr(hasBase(DeclRef))), *If,
54 *Result.Context)
55 .empty() ||
56 // FIXME: We should still warn if the paremater is implicitly converted to
57 // bool.
58 !match(findAll(callExpr(hasAnyArgument(ignoringParenImpCasts(DeclRef)))),
59 *If, *Result.Context)
60 .empty() ||
61 !match(findAll(cxxDeleteExpr(has(ignoringParenImpCasts(expr(DeclRef))))),
62 *If, *Result.Context)
63 .empty())
64 return;
65
66 diag(Var->getLocStart(), "dubious check of 'bool *' against 'nullptr', did "
67 "you mean to dereference it?")
68 << FixItHint::CreateInsertion(Var->getLocStart(), "*");
69 }
70
71 } // namespace bugprone
72 } // namespace tidy
73 } // namespace clang
clang::ast_matchers
Definition: ClangTidyDiagnosticConsumer.h:27
BoolPointerImplicitConversionCheck.h
clang
Definition: AndroidTidyModule.cpp:28
DeclRef
const DeclRefExpr * DeclRef
Definition: UseAfterMoveCheck.cpp:30