forked from OSchip/llvm-project
71 lines
2.2 KiB
C++
71 lines
2.2 KiB
C++
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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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#include "clang/Analysis/PathSensitive/Checkers/DivZeroChecker.h"
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using namespace clang;
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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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if (ExplodedNode *N = C.GenerateNode(B, stateZero, true)) {
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if (!BT)
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BT = new BuiltinBug(0, "Division by zero");
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EnhancedBugReport *R =
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new EnhancedBugReport(*BT, BT->getDescription().c_str(), N);
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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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if (stateNotZero != C.getState())
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C.addTransition(C.GenerateNode(B, stateNotZero));
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}
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