1 //== DivZeroChecker.cpp - Division by zero checker --------------*- C++ -*--==//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This defines DivZeroChecker, a builtin check in ExprEngine that performs
11 // checks for division by zeros.
13 //===----------------------------------------------------------------------===//
15 #include "ClangSACheckers.h"
16 #include "clang/StaticAnalyzer/Core/Checker.h"
17 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
18 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
19 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
21 using namespace clang;
25 class DivZeroChecker : public Checker< check::PreStmt<BinaryOperator> > {
26 mutable llvm::OwningPtr<BuiltinBug> BT;
28 void checkPreStmt(const BinaryOperator *B, CheckerContext &C) const;
30 } // end anonymous namespace
32 void DivZeroChecker::checkPreStmt(const BinaryOperator *B,
33 CheckerContext &C) const {
34 BinaryOperator::Opcode Op = B->getOpcode();
41 if (!B->getRHS()->getType()->isIntegerType() ||
42 !B->getRHS()->getType()->isScalarType())
45 SVal Denom = C.getState()->getSVal(B->getRHS());
46 const DefinedSVal *DV = dyn_cast<DefinedSVal>(&Denom);
48 // Divide-by-undefined handled in the generic checking for uses of
53 // Check for divide by zero.
54 ConstraintManager &CM = C.getConstraintManager();
55 const ProgramState *stateNotZero, *stateZero;
56 llvm::tie(stateNotZero, stateZero) = CM.assumeDual(C.getState(), *DV);
58 if (stateZero && !stateNotZero) {
59 if (ExplodedNode *N = C.generateSink(stateZero)) {
61 BT.reset(new BuiltinBug("Division by zero"));
64 new BugReport(*BT, BT->getDescription(), N);
66 R->addVisitor(bugreporter::getTrackNullOrUndefValueVisitor(N,
67 bugreporter::GetDenomExpr(N)));
74 // If we get here, then the denom should not be zero. We abandon the implicit
75 // zero denom case for now.
76 C.addTransition(stateNotZero);
79 void ento::registerDivZeroChecker(CheckerManager &mgr) {
80 mgr.registerChecker<DivZeroChecker>();