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//=== CastSizeChecker.cpp ---------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// CastSizeChecker checks when casting a malloc'ed symbolic region to type T,
// whether the size of the symbolic region is a multiple of the size of T.
//
//===----------------------------------------------------------------------===//
#include "clang/AST/CharUnits.h"
#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerVisitor.h"
#include "InternalChecks.h"
using namespace clang;
using namespace ento;
namespace {
class CastSizeChecker : public CheckerVisitor<CastSizeChecker> {
BuiltinBug *BT;
public:
CastSizeChecker() : BT(0) {}
static void *getTag();
void PreVisitCastExpr(CheckerContext &C, const CastExpr *B);
};
}
void *CastSizeChecker::getTag() {
static int x;
return &x;
}
void CastSizeChecker::PreVisitCastExpr(CheckerContext &C, const CastExpr *CE) {
const Expr *E = CE->getSubExpr();
ASTContext &Ctx = C.getASTContext();
QualType ToTy = Ctx.getCanonicalType(CE->getType());
const PointerType *ToPTy = dyn_cast<PointerType>(ToTy.getTypePtr());
if (!ToPTy)
return;
QualType ToPointeeTy = ToPTy->getPointeeType();
// Only perform the check if 'ToPointeeTy' is a complete type.
if (ToPointeeTy->isIncompleteType())
return;
const GRState *state = C.getState();
const MemRegion *R = state->getSVal(E).getAsRegion();
if (R == 0)
return;
const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R);
if (SR == 0)
return;
SValBuilder &svalBuilder = C.getSValBuilder();
SVal extent = SR->getExtent(svalBuilder);
const llvm::APSInt *extentInt = svalBuilder.getKnownValue(state, extent);
if (!extentInt)
return;
CharUnits regionSize = CharUnits::fromQuantity(extentInt->getSExtValue());
CharUnits typeSize = C.getASTContext().getTypeSizeInChars(ToPointeeTy);
// Ignore void, and a few other un-sizeable types.
if (typeSize.isZero())
return;
if (regionSize % typeSize != 0) {
if (ExplodedNode *errorNode = C.generateSink()) {
if (!BT)
BT = new BuiltinBug("Cast region with wrong size.",
"Cast a region whose size is not a multiple of the"
" destination type size.");
RangedBugReport *R = new RangedBugReport(*BT, BT->getDescription(),
errorNode);
R->addRange(CE->getSourceRange());
C.EmitReport(R);
}
}
}
void ento::RegisterCastSizeChecker(ExprEngine &Eng) {
Eng.registerCheck(new CastSizeChecker());
}
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