clang 19.0.0git
BoolAssignmentChecker.cpp
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1//== BoolAssignmentChecker.cpp - Boolean assignment checker -----*- C++ -*--==//
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//
9// This defines BoolAssignmentChecker, a builtin check in ExprEngine that
10// performs checks for assignment of non-Boolean values to Boolean variables.
11//
12//===----------------------------------------------------------------------===//
13
20#include <optional>
21
22using namespace clang;
23using namespace ento;
24
25namespace {
26class BoolAssignmentChecker : public Checker<check::Bind> {
27 const BugType BT{this, "Assignment of a non-Boolean value"};
28 void emitReport(ProgramStateRef State, CheckerContext &C,
29 bool IsTainted = false) const;
30
31public:
32 void checkBind(SVal Loc, SVal Val, const Stmt *S, CheckerContext &C) const;
33};
34} // end anonymous namespace
35
36void BoolAssignmentChecker::emitReport(ProgramStateRef State, CheckerContext &C,
37 bool IsTainted) const {
38 if (ExplodedNode *N = C.generateNonFatalErrorNode(State)) {
39 StringRef Msg = IsTainted ? "Might assign a tainted non-Boolean value"
40 : "Assignment of a non-Boolean value";
41 C.emitReport(std::make_unique<PathSensitiveBugReport>(BT, Msg, N));
42 }
43}
44
45static bool isBooleanType(QualType Ty) {
46 if (Ty->isBooleanType()) // C++ or C99
47 return true;
48
49 if (const TypedefType *TT = Ty->getAs<TypedefType>())
50 return TT->getDecl()->getName() == "BOOL" || // Objective-C
51 TT->getDecl()->getName() == "_Bool" || // stdbool.h < C99
52 TT->getDecl()->getName() == "Boolean"; // MacTypes.h
53
54 return false;
55}
56
57void BoolAssignmentChecker::checkBind(SVal Loc, SVal Val, const Stmt *S,
58 CheckerContext &C) const {
59
60 // We are only interested in stores into Booleans.
61 const TypedValueRegion *TR =
62 dyn_cast_or_null<TypedValueRegion>(Loc.getAsRegion());
63
64 if (!TR)
65 return;
66
67 QualType RegTy = TR->getValueType();
68
69 if (!isBooleanType(RegTy))
70 return;
71
72 // Get the value of the right-hand side. We only care about values
73 // that are defined (UnknownVals and UndefinedVals are handled by other
74 // checkers).
75 std::optional<NonLoc> NV = Val.getAs<NonLoc>();
76 if (!NV)
77 return;
78
79 // Check if the assigned value meets our criteria for correctness. It must
80 // be a value that is either 0 or 1. One way to check this is to see if
81 // the value is possibly < 0 (for a negative value) or greater than 1.
82 ProgramStateRef State = C.getState();
83 BasicValueFactory &BVF = C.getSValBuilder().getBasicValueFactory();
84 ConstraintManager &CM = C.getConstraintManager();
85
86 llvm::APSInt Zero = BVF.getValue(0, RegTy);
87 llvm::APSInt One = BVF.getValue(1, RegTy);
88
89 ProgramStateRef StIn, StOut;
90 std::tie(StIn, StOut) = CM.assumeInclusiveRangeDual(State, *NV, Zero, One);
91
92 if (!StIn)
93 emitReport(StOut, C);
94 if (StIn && StOut && taint::isTainted(State, *NV))
95 emitReport(StOut, C, /*IsTainted=*/true);
96}
97
98void ento::registerBoolAssignmentChecker(CheckerManager &Mgr) {
99 Mgr.registerChecker<BoolAssignmentChecker>();
100}
101
102bool ento::shouldRegisterBoolAssignmentChecker(const CheckerManager &Mgr) {
103 return true;
104}
static bool isBooleanType(QualType Ty)
A (possibly-)qualified type.
Definition: Type.h:940
Stmt - This represents one statement.
Definition: Stmt.h:84
bool isBooleanType() const
Definition: Type.h:8038
const T * getAs() const
Member-template getAs<specific type>'.
Definition: Type.h:8131
CHECKER * registerChecker(AT &&... Args)
Used to register checkers.
ProgramStatePair assumeInclusiveRangeDual(ProgramStateRef State, NonLoc Value, const llvm::APSInt &From, const llvm::APSInt &To)
Returns a pair of states (StInRange, StOutOfRange) where the given value is assumed to be in the rang...
SVal - This represents a symbolic expression, which can be either an L-value or an R-value.
Definition: SVals.h:55
std::optional< T > getAs() const
Convert to the specified SVal type, returning std::nullopt if this SVal is not of the desired type.
Definition: SVals.h:86
const MemRegion * getAsRegion() const
Definition: SVals.cpp:120
TypedValueRegion - An abstract class representing regions having a typed value.
Definition: MemRegion.h:530
virtual QualType getValueType() const =0
bool isTainted(ProgramStateRef State, const Stmt *S, const LocationContext *LCtx, TaintTagType Kind=TaintTagGeneric)
Check if the statement has a tainted value in the given state.
Definition: Taint.cpp:147
bool Zero(InterpState &S, CodePtr OpPC)
Definition: Interp.h:1877
The JSON file list parser is used to communicate input to InstallAPI.