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//== ArrayBoundChecker.cpp ------------------------------*- C++ -*--==//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
// This file defines ArrayBoundChecker, which is a path-sensitive check
// which looks for an out-of-bound array element access.
#include "GRExprEngineInternalChecks.h"
#include "clang/Checker/PathSensitive/GRExprEngine.h"
#include "clang/Checker/BugReporter/BugReporter.h"
#include "clang/Checker/PathSensitive/CheckerVisitor.h"
using namespace clang;
namespace {
class ArrayBoundChecker :
public CheckerVisitor<ArrayBoundChecker> {
BuiltinBug *BT;
ArrayBoundChecker() : BT(0) {}
static void *getTag();
void VisitLocation(CheckerContext &C, const Stmt *S, SVal l);
void clang::RegisterArrayBoundChecker(GRExprEngine &Eng) {
Eng.registerCheck(new ArrayBoundChecker());
void *ArrayBoundChecker::getTag() {
static int x = 0; return &x;
void ArrayBoundChecker::VisitLocation(CheckerContext &C, const Stmt *S, SVal l){
// Check for out of bound array element access.
const MemRegion *R = l.getAsRegion();
if (!R)
R = R->StripCasts();
const ElementRegion *ER = dyn_cast<ElementRegion>(R);
if (!ER)
// Get the index of the accessed element.
DefinedOrUnknownSVal &Idx = cast<DefinedOrUnknownSVal>(ER->getIndex());
const GRState *state = C.getState();
// Get the size of the array.
DefinedOrUnknownSVal NumElements
= C.getStoreManager().getSizeInElements(state, ER->getSuperRegion(),
const GRState *StInBound = state->AssumeInBound(Idx, NumElements, true);
const GRState *StOutBound = state->AssumeInBound(Idx, NumElements, false);
if (StOutBound && !StInBound) {
ExplodedNode *N = C.GenerateSink(StOutBound);
if (!N)
if (!BT)
BT = new BuiltinBug("Out-of-bound array access",
"Access out-of-bound array element (buffer overflow)");
// FIXME: It would be nice to eventually make this diagnostic more clear,
// e.g., by referencing the original declaration or by saying *why* this
// reference is outside the range.
// Generate a report for this bug.
RangedBugReport *report =
new RangedBugReport(*BT, BT->getDescription(), N);
// Array bound check succeeded. From this point forward the array bound
// should always succeed.