2009-10-31 18:02:37 +08:00
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//== DivZeroChecker.cpp - Division by zero checker --------------*- C++ -*--==//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This defines DivZeroChecker, a builtin check in GRExprEngine that performs
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// checks for division by zeros.
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//
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//===----------------------------------------------------------------------===//
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2009-11-07 04:47:51 +08:00
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#include "clang/Analysis/PathSensitive/CheckerVisitor.h"
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#include "GRExprEngineInternalChecks.h"
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2009-10-31 18:02:37 +08:00
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using namespace clang;
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2009-11-07 04:47:51 +08:00
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namespace {
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2009-11-28 14:07:30 +08:00
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class DivZeroChecker : public CheckerVisitor<DivZeroChecker> {
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2009-11-07 04:47:51 +08:00
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BuiltinBug *BT;
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public:
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DivZeroChecker() : BT(0) {}
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static void *getTag();
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void PreVisitBinaryOperator(CheckerContext &C, const BinaryOperator *B);
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};
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} // end anonymous namespace
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void clang::RegisterDivZeroChecker(GRExprEngine &Eng) {
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Eng.registerCheck(new DivZeroChecker());
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}
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2009-10-31 18:02:37 +08:00
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void *DivZeroChecker::getTag() {
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static int x;
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return &x;
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}
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void DivZeroChecker::PreVisitBinaryOperator(CheckerContext &C,
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const BinaryOperator *B) {
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BinaryOperator::Opcode Op = B->getOpcode();
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if (Op != BinaryOperator::Div &&
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Op != BinaryOperator::Rem &&
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Op != BinaryOperator::DivAssign &&
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Op != BinaryOperator::RemAssign)
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return;
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if (!B->getRHS()->getType()->isIntegerType() ||
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!B->getRHS()->getType()->isScalarType())
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return;
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SVal Denom = C.getState()->getSVal(B->getRHS());
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const DefinedSVal *DV = dyn_cast<DefinedSVal>(&Denom);
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// Divide-by-undefined handled in the generic checking for uses of
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// undefined values.
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if (!DV)
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return;
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// Check for divide by zero.
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ConstraintManager &CM = C.getConstraintManager();
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const GRState *stateNotZero, *stateZero;
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llvm::tie(stateNotZero, stateZero) = CM.AssumeDual(C.getState(), *DV);
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if (stateZero && !stateNotZero) {
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2009-11-24 06:22:01 +08:00
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if (ExplodedNode *N = C.GenerateSink(stateZero)) {
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2009-10-31 18:02:37 +08:00
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if (!BT)
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2009-11-06 08:44:32 +08:00
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BT = new BuiltinBug("Division by zero");
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2009-10-31 18:02:37 +08:00
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EnhancedBugReport *R =
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2009-11-14 20:08:24 +08:00
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new EnhancedBugReport(*BT, BT->getDescription(), N);
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2009-10-31 18:02:37 +08:00
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R->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue,
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bugreporter::GetDenomExpr(N));
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C.EmitReport(R);
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}
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return;
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}
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// If we get here, then the denom should not be zero. We abandon the implicit
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// zero denom case for now.
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2009-11-24 06:22:01 +08:00
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C.addTransition(stateNotZero);
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2009-10-31 18:02:37 +08:00
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}
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