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ClamAV is an open source (GPLv2) anti-virus toolkit.
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clamav/libclamav/c++/ClamBCRTChecks.cpp

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/*
* Compile LLVM bytecode to ClamAV bytecode.
*
* Copyright (C) 2009-2010 Sourcefire, Inc.
*
* Authors: Török Edvin
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
*/
#define DEBUG_TYPE "clambc-rtcheck"
#include "ClamBCModule.h"
#include "ClamBCDiagnostics.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/SCCIterator.h"
#include "llvm/Analysis/CallGraph.h"
#include "llvm/Analysis/Verifier.h"
#include "llvm/Analysis/DebugInfo.h"
#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/ConstantFolding.h"
//#include "llvm/Analysis/LiveValues.h"
//
#ifdef LLVM29
#include "llvm/Analysis/ValueTracking.h"
#include "PointerTracking.h"
#else
#include "llvm/Analysis/PointerTracking.h"
#endif
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
#include "llvm/Analysis/ScalarEvolutionExpander.h"
#include "llvm/Config/config.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Instructions.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/Intrinsics.h"
#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/DataFlow.h"
#include "llvm/Support/InstIterator.h"
#include "llvm/Support/InstVisitor.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Support/Debug.h"
#ifndef LLVM28
#define LLVM28
#endif
#ifdef LLVM28
#define DEFINEPASS(passname) passname() : FunctionPass(ID)
#else
#define DEFINEPASS(passname) passname() : FunctionPass(&ID)
#endif
using namespace llvm;
#ifndef LLVM29
static Value *GetUnderlyingObject(Value *P, TargetData *TD)
{
return P->getUnderlyingObject();
}
#endif
namespace {
class PtrVerifier : public FunctionPass {
private:
DenseSet<Function*> badFunctions;
CallGraphNode *rootNode;
public:
static char ID;
DEFINEPASS(PtrVerifier), rootNode(0) {}
virtual bool runOnFunction(Function &F) {
DEBUG(errs() << "Running on " << F.getName() << "\n");
DEBUG(F.dump());
Changed = false;
BaseMap.clear();
BoundsMap.clear();
AbrtBB = 0;
valid = true;
if (!rootNode) {
rootNode = getAnalysis<CallGraph>().getRoot();
// No recursive functions for now.
// In the future we may insert runtime checks for stack depth.
for (scc_iterator<CallGraphNode*> SCCI = scc_begin(rootNode),
E = scc_end(rootNode); SCCI != E; ++SCCI) {
const std::vector<CallGraphNode*> &nextSCC = *SCCI;
if (nextSCC.size() > 1 || SCCI.hasLoop()) {
errs() << "INVALID: Recursion detected, callgraph SCC components: ";
for (std::vector<CallGraphNode*>::const_iterator I = nextSCC.begin(),
E = nextSCC.end(); I != E; ++I) {
Function *FF = (*I)->getFunction();
if (FF) {
errs() << FF->getName() << ", ";
badFunctions.insert(FF);
}
}
if (SCCI.hasLoop())
errs() << "(self-loop)";
errs() << "\n";
}
// we could also have recursion via function pointers, but we don't
// allow calls to unknown functions, see runOnFunction() below
}
}
BasicBlock::iterator It = F.getEntryBlock().begin();
while (isa<AllocaInst>(It) || isa<PHINode>(It)) ++It;
EP = &*It;
TD = &getAnalysis<TargetData>();
SE = &getAnalysis<ScalarEvolution>();
PT = &getAnalysis<PointerTracking>();
DT = &getAnalysis<DominatorTree>();
std::vector<Instruction*> insns;
BasicBlock *LastBB = 0;
bool skip = false;
for (inst_iterator I=inst_begin(F),E=inst_end(F); I != E;++I) {
Instruction *II = &*I;
if (II->getParent() != LastBB) {
LastBB = II->getParent();
skip = DT->getNode(LastBB) == 0;
}
if (skip)
continue;
if (isa<LoadInst>(II) || isa<StoreInst>(II) || isa<MemIntrinsic>(II))
insns.push_back(II);
if (CallInst *CI = dyn_cast<CallInst>(II)) {
Value *V = CI->getCalledValue()->stripPointerCasts();
Function *F = dyn_cast<Function>(V);
if (!F) {
printLocation(CI, true);
errs() << "Could not determine call target\n";
valid = 0;
continue;
}
if (!F->isDeclaration())
continue;
insns.push_back(CI);
}
}
while (!insns.empty()) {
Instruction *II = insns.back();
insns.pop_back();
DEBUG(dbgs() << "checking " << *II << "\n");
if (LoadInst *LI = dyn_cast<LoadInst>(II)) {
const Type *Ty = LI->getType();
valid &= validateAccess(LI->getPointerOperand(),
TD->getTypeAllocSize(Ty), LI);
} else if (StoreInst *SI = dyn_cast<StoreInst>(II)) {
const Type *Ty = SI->getOperand(0)->getType();
valid &= validateAccess(SI->getPointerOperand(),
TD->getTypeAllocSize(Ty), SI);
} else if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(II)) {
valid &= validateAccess(MI->getDest(), MI->getLength(), MI);
if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(MI)) {
valid &= validateAccess(MTI->getSource(), MI->getLength(), MI);
}
} else if (CallInst *CI = dyn_cast<CallInst>(II)) {
Value *V = CI->getCalledValue()->stripPointerCasts();
Function *F = cast<Function>(V);
const FunctionType *FTy = F->getFunctionType();
CallSite CS(CI);
if (F->getName().equals("memcmp") && FTy->getNumParams() == 3) {
valid &= validateAccess(CS.getArgument(0), CS.getArgument(2), CI);
valid &= validateAccess(CS.getArgument(1), CS.getArgument(2), CI);
continue;
}
unsigned i;
#ifdef CLAMBC_COMPILER
i = 0;
#else
i = 1;// skip hidden ctx*
#endif
for (;i<FTy->getNumParams();i++) {
if (isa<PointerType>(FTy->getParamType(i))) {
Value *Ptr = CS.getArgument(i);
if (i+1 >= FTy->getNumParams()) {
printLocation(CI, false);
errs() << "Call to external function with pointer parameter last cannot be analyzed\n";
errs() << *CI << "\n";
valid = 0;
break;
}
Value *Size = CS.getArgument(i+1);
if (!Size->getType()->isIntegerTy()) {
printLocation(CI, false);
errs() << "Pointer argument must be followed by integer argument representing its size\n";
errs() << *CI << "\n";
valid = 0;
break;
}
valid &= validateAccess(Ptr, Size, CI);
}
}
}
}
if (badFunctions.count(&F))
valid = 0;
if (!valid) {
DEBUG(F.dump());
ClamBCModule::stop("Verification found errors!", &F);
// replace function with call to abort
std::vector<const Type*>args;
FunctionType* abrtTy = FunctionType::get(
Type::getVoidTy(F.getContext()),args,false);
Constant *func_abort =
F.getParent()->getOrInsertFunction("abort", abrtTy);
BasicBlock *BB = &F.getEntryBlock();
Instruction *I = &*BB->begin();
Instruction *UI = new UnreachableInst(F.getContext(), I);
CallInst *AbrtC = CallInst::Create(func_abort, "", UI);
AbrtC->setCallingConv(CallingConv::C);
AbrtC->setTailCall(true);
AbrtC->setDoesNotReturn(true);
AbrtC->setDoesNotThrow(true);
// remove all instructions from entry
BasicBlock::iterator BBI = I, BBE=BB->end();
while (BBI != BBE) {
if (!BBI->use_empty())
BBI->replaceAllUsesWith(UndefValue::get(BBI->getType()));
BB->getInstList().erase(BBI++);
}
}
return Changed;
}
virtual void releaseMemory() {
badFunctions.clear();
}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<TargetData>();
AU.addRequired<DominatorTree>();
AU.addRequired<ScalarEvolution>();
AU.addRequired<PointerTracking>();
AU.addRequired<CallGraph>();
}
bool isValid() const { return valid; }
private:
PointerTracking *PT;
TargetData *TD;
ScalarEvolution *SE;
DominatorTree *DT;
DenseMap<Value*, Value*> BaseMap;
DenseMap<Value*, Value*> BoundsMap;
BasicBlock *AbrtBB;
bool Changed;
bool valid;
Instruction *EP;
Instruction *getInsertPoint(Value *V)
{
BasicBlock::iterator It = EP;
if (Instruction *I = dyn_cast<Instruction>(V)) {
It = I;
++It;
}
return &*It;
}
Value *getPointerBase(Value *Ptr)
{
if (BaseMap.count(Ptr))
return BaseMap[Ptr];
Value *P = Ptr->stripPointerCasts();
if (BaseMap.count(P)) {
return BaseMap[Ptr] = BaseMap[P];
}
Value *P2 = GetUnderlyingObject(P, TD);
if (P2 != P) {
Value *V = getPointerBase(P2);
return BaseMap[Ptr] = V;
}
const Type *P8Ty =
PointerType::getUnqual(Type::getInt8Ty(Ptr->getContext()));
if (PHINode *PN = dyn_cast<PHINode>(Ptr)) {
BasicBlock::iterator It = PN;
++It;
PHINode *newPN = PHINode::Create(P8Ty, ".verif.base", &*It);
Changed = true;
BaseMap[Ptr] = newPN;
for (unsigned i=0;i<PN->getNumIncomingValues();i++) {
Value *Inc = PN->getIncomingValue(i);
Value *V = getPointerBase(Inc);
newPN->addIncoming(V, PN->getIncomingBlock(i));
}
return newPN;
}
if (SelectInst *SI = dyn_cast<SelectInst>(Ptr)) {
BasicBlock::iterator It = SI;
++It;
Value *TrueB = getPointerBase(SI->getTrueValue());
Value *FalseB = getPointerBase(SI->getFalseValue());
if (TrueB && FalseB) {
SelectInst *NewSI = SelectInst::Create(SI->getCondition(), TrueB,
FalseB, ".select.base", &*It);
Changed = true;
return BaseMap[Ptr] = NewSI;
}
}
if (Ptr->getType() != P8Ty) {
if (Constant *C = dyn_cast<Constant>(Ptr))
Ptr = ConstantExpr::getPointerCast(C, P8Ty);
else {
Instruction *I = getInsertPoint(Ptr);
Ptr = new BitCastInst(Ptr, P8Ty, "", I);
}
}
return BaseMap[Ptr] = Ptr;
}
Value* getPointerBounds(Value *Base) {
if (BoundsMap.count(Base))
return BoundsMap[Base];
const Type *I64Ty =
Type::getInt64Ty(Base->getContext());
#ifndef CLAMBC_COMPILER
// first arg is hidden ctx
if (Argument *A = dyn_cast<Argument>(Base)) {
if (A->getArgNo() == 0) {
const Type *Ty = cast<PointerType>(A->getType())->getElementType();
return ConstantInt::get(I64Ty, TD->getTypeAllocSize(Ty));
}
}
if (LoadInst *LI = dyn_cast<LoadInst>(Base)) {
Value *V = GetUnderlyingObject(LI->getPointerOperand()->stripPointerCasts(), TD);
if (Argument *A = dyn_cast<Argument>(V)) {
if (A->getArgNo() == 0) {
// pointers from hidden ctx are trusted to be at least the
// size they say they are
const Type *Ty = cast<PointerType>(LI->getType())->getElementType();
return ConstantInt::get(I64Ty, TD->getTypeAllocSize(Ty));
}
}
}
#endif
if (PHINode *PN = dyn_cast<PHINode>(Base)) {
BasicBlock::iterator It = PN;
++It;
PHINode *newPN = PHINode::Create(I64Ty, ".verif.bounds", &*It);
Changed = true;
BoundsMap[Base] = newPN;
bool good = true;
for (unsigned i=0;i<PN->getNumIncomingValues();i++) {
Value *Inc = PN->getIncomingValue(i);
Value *B = getPointerBounds(Inc);
if (!B) {
good = false;
B = ConstantInt::get(newPN->getType(), 0);
DEBUG(dbgs() << "bounds not found while solving phi node: " << *Inc
<< "\n");
}
newPN->addIncoming(B, PN->getIncomingBlock(i));
}
if (!good)
newPN = 0;
return BoundsMap[Base] = newPN;
}
if (SelectInst *SI = dyn_cast<SelectInst>(Base)) {
BasicBlock::iterator It = SI;
++It;
Value *TrueB = getPointerBounds(SI->getTrueValue());
Value *FalseB = getPointerBounds(SI->getFalseValue());
if (TrueB && FalseB) {
SelectInst *NewSI = SelectInst::Create(SI->getCondition(), TrueB,
FalseB, ".select.bounds", &*It);
Changed = true;
return BoundsMap[Base] = NewSI;
}
}
const Type *Ty;
Value *V = PT->computeAllocationCountValue(Base, Ty);
if (!V) {
Base = Base->stripPointerCasts();
if (CallInst *CI = dyn_cast<CallInst>(Base)) {
Function *F = CI->getCalledFunction();
const FunctionType *FTy = F->getFunctionType();
// last operand is always size for this API call kind
if (F->isDeclaration() && FTy->getNumParams() > 0) {
CallSite CS(CI);
if (FTy->getParamType(FTy->getNumParams()-1)->isIntegerTy())
V = CS.getArgument(FTy->getNumParams()-1);
}
}
if (!V)
return BoundsMap[Base] = 0;
} else {
unsigned size = TD->getTypeAllocSize(Ty);
if (size > 1) {
Constant *C = cast<Constant>(V);
C = ConstantExpr::getMul(C,
ConstantInt::get(Type::getInt32Ty(C->getContext()),
size));
V = C;
}
}
if (V->getType() != I64Ty) {
if (Constant *C = dyn_cast<Constant>(V))
V = ConstantExpr::getZExt(C, I64Ty);
else {
Instruction *I = getInsertPoint(V);
V = new ZExtInst(V, I64Ty, "", I);
}
}
return BoundsMap[Base] = V;
}
MDNode *getLocation(Instruction *I, bool &Approximate, unsigned MDDbgKind)
{
Approximate = false;
if (MDNode *Dbg = I->getMetadata(MDDbgKind))
return Dbg;
if (!MDDbgKind)
return 0;
Approximate = true;
BasicBlock::iterator It = I;
while (It != I->getParent()->begin()) {
--It;
if (MDNode *Dbg = It->getMetadata(MDDbgKind))
return Dbg;
}
BasicBlock *BB = I->getParent();
while ((BB = BB->getUniquePredecessor())) {
It = BB->end();
while (It != BB->begin()) {
--It;
if (MDNode *Dbg = It->getMetadata(MDDbgKind))
return Dbg;
}
}
return 0;
}
bool insertCheck(const SCEV *Idx, const SCEV *Limit, Instruction *I,
bool strict)
{
if (isa<SCEVCouldNotCompute>(Idx) && isa<SCEVCouldNotCompute>(Limit)) {
errs() << "Could not compute the index and the limit!: \n" << *I << "\n";
return false;
}
if (isa<SCEVCouldNotCompute>(Idx)) {
errs() << "Could not compute index: \n" << *I << "\n";
return false;
}
if (isa<SCEVCouldNotCompute>(Limit)) {
errs() << "Could not compute limit: " << *I << "\n";
return false;
}
BasicBlock *BB = I->getParent();
BasicBlock::iterator It = I;
BasicBlock *newBB = SplitBlock(BB, &*It, this);
PHINode *PN;
unsigned MDDbgKind = I->getContext().getMDKindID("dbg");
//verifyFunction(*BB->getParent());
if (!AbrtBB) {
std::vector<const Type*>args;
FunctionType* abrtTy = FunctionType::get(
Type::getVoidTy(BB->getContext()),args,false);
args.push_back(Type::getInt32Ty(BB->getContext()));
FunctionType* rterrTy = FunctionType::get(
Type::getInt32Ty(BB->getContext()),args,false);
Constant *func_abort =
BB->getParent()->getParent()->getOrInsertFunction("abort", abrtTy);
Constant *func_rterr =
BB->getParent()->getParent()->getOrInsertFunction("bytecode_rt_error", rterrTy);
AbrtBB = BasicBlock::Create(BB->getContext(), "", BB->getParent());
PN = PHINode::Create(Type::getInt32Ty(BB->getContext()),"",
AbrtBB);
if (MDDbgKind) {
CallInst *RtErrCall = CallInst::Create(func_rterr, PN, "", AbrtBB);
RtErrCall->setCallingConv(CallingConv::C);
RtErrCall->setTailCall(true);
RtErrCall->setDoesNotThrow(true);
}
CallInst* AbrtC = CallInst::Create(func_abort, "", AbrtBB);
AbrtC->setCallingConv(CallingConv::C);
AbrtC->setTailCall(true);
AbrtC->setDoesNotReturn(true);
AbrtC->setDoesNotThrow(true);
new UnreachableInst(BB->getContext(), AbrtBB);
DT->addNewBlock(AbrtBB, BB);
//verifyFunction(*BB->getParent());
} else {
PN = cast<PHINode>(AbrtBB->begin());
}
unsigned locationid = 0;
bool Approximate;
if (MDNode *Dbg = getLocation(I, Approximate, MDDbgKind)) {
DILocation Loc(Dbg);
locationid = Loc.getLineNumber() << 8;
unsigned col = Loc.getColumnNumber();
if (col > 254)
col = 254;
if (Approximate)
col = 255;
locationid |= col;
// Loc.getFilename();
} else {
static int wcounters = 100000;
locationid = (wcounters++)<<8;
/*errs() << "fake location: " << (locationid>>8) << "\n";
I->dump();
I->getParent()->dump();*/
}
PN->addIncoming(ConstantInt::get(Type::getInt32Ty(BB->getContext()),
locationid), BB);
TerminatorInst *TI = BB->getTerminator();
SCEVExpander expander(*SE);
Value *IdxV = expander.expandCodeFor(Idx, Limit->getType(), TI);
/* if (isa<PointerType>(IdxV->getType())) {
IdxV = new PtrToIntInst(IdxV, Idx->getType(), "", TI);
}*/
//verifyFunction(*BB->getParent());
Value *LimitV = expander.expandCodeFor(Limit, Limit->getType(), TI);
//verifyFunction(*BB->getParent());
Value *Cond = new ICmpInst(TI, strict ?
ICmpInst::ICMP_ULT :
ICmpInst::ICMP_ULE, IdxV, LimitV);
//verifyFunction(*BB->getParent());
BranchInst::Create(newBB, AbrtBB, Cond, TI);
TI->eraseFromParent();
// Update dominator info
BasicBlock *DomBB =
DT->findNearestCommonDominator(BB,
DT->getNode(AbrtBB)->getIDom()->getBlock());
DT->changeImmediateDominator(AbrtBB, DomBB);
//verifyFunction(*BB->getParent());
return true;
}
static void MakeCompatible(ScalarEvolution *SE, const SCEV*& LHS, const SCEV*& RHS)
{
if (const SCEVZeroExtendExpr *ZL = dyn_cast<SCEVZeroExtendExpr>(LHS))
LHS = ZL->getOperand();
if (const SCEVZeroExtendExpr *ZR = dyn_cast<SCEVZeroExtendExpr>(RHS))
RHS = ZR->getOperand();
const Type* LTy = SE->getEffectiveSCEVType(LHS->getType());
const Type *RTy = SE->getEffectiveSCEVType(RHS->getType());
if (SE->getTypeSizeInBits(RTy) > SE->getTypeSizeInBits(LTy))
LTy = RTy;
LHS = SE->getNoopOrZeroExtend(LHS, LTy);
RHS = SE->getNoopOrZeroExtend(RHS, LTy);
}
bool checkCond(Instruction *ICI, Instruction *I, bool equal)
{
for (Value::use_iterator JU=ICI->use_begin(),JUE=ICI->use_end();
JU != JUE; ++JU) {
Value *JU_V = *JU;
if (BranchInst *BI = dyn_cast<BranchInst>(JU_V)) {
if (!BI->isConditional())
continue;
BasicBlock *S = BI->getSuccessor(equal);
if (DT->dominates(S, I->getParent()))
return true;
}
if (BinaryOperator *BI = dyn_cast<BinaryOperator>(JU_V)) {
if (BI->getOpcode() == Instruction::Or &&
checkCond(BI, I, equal))
return true;
if (BI->getOpcode() == Instruction::And &&
checkCond(BI, I, !equal))
return true;
}
}
return false;
}
bool checkCondition(Instruction *CI, Instruction *I)
{
for (Value::use_iterator U=CI->use_begin(),UE=CI->use_end();
U != UE; ++U) {
Value *U_V = *U;
if (ICmpInst *ICI = dyn_cast<ICmpInst>(U_V)) {
if (ICI->getOperand(0)->stripPointerCasts() == CI &&
isa<ConstantPointerNull>(ICI->getOperand(1))) {
if (checkCond(ICI, I, ICI->getPredicate() == ICmpInst::ICMP_EQ))
return true;
}
}
}
return false;
}
bool validateAccess(Value *Pointer, Value *Length, Instruction *I)
{
// get base
Value *Base = getPointerBase(Pointer);
Value *SBase = Base->stripPointerCasts();
// get bounds
Value *Bounds = getPointerBounds(SBase);
if (!Bounds) {
printLocation(I, true);
errs() << "no bounds for base ";
printValue(SBase);
errs() << " while checking access to ";
printValue(Pointer);
errs() << " of length ";
printValue(Length);
errs() << "\n";
return false;
}
if (CallInst *CI = dyn_cast<CallInst>(Base->stripPointerCasts())) {
if (I->getParent() == CI->getParent()) {
printLocation(I, true);
errs() << "no null pointer check of pointer ";
printValue(Base, false, true);
errs() << " obtained by function call";
errs() << " before use in same block\n";
return false;
}
if (!checkCondition(CI, I)) {
printLocation(I, true);
errs() << "no null pointer check of pointer ";
printValue(Base, false, true);
errs() << " obtained by function call";
errs() << " before use\n";
return false;
}
}
const Type *I64Ty =
Type::getInt64Ty(Base->getContext());
const SCEV *SLen = SE->getSCEV(Length);
const SCEV *OffsetP = SE->getMinusSCEV(SE->getSCEV(Pointer),
SE->getSCEV(Base));
SLen = SE->getNoopOrZeroExtend(SLen, I64Ty);
OffsetP = SE->getNoopOrZeroExtend(OffsetP, I64Ty);
const SCEV *Limit = SE->getSCEV(Bounds);
Limit = SE->getNoopOrZeroExtend(Limit, I64Ty);
DEBUG(dbgs() << "Checking access to " << *Pointer << " of length " <<
*Length << "\n");
if (OffsetP == Limit) {
printLocation(I, true);
errs() << "OffsetP == Limit: " << *OffsetP << "\n";
errs() << " while checking access to ";
printValue(Pointer);
errs() << " of length ";
printValue(Length);
errs() << "\n";
return false;
}
if (SLen == Limit) {
if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(OffsetP)) {
if (SC->isZero())
return true;
}
errs() << "SLen == Limit: " << *SLen << "\n";
errs() << " while checking access to " << *Pointer << " of length "
<< *Length << " at " << *I << "\n";
return false;
}
bool valid = true;
SLen = SE->getAddExpr(OffsetP, SLen);
// check that offset + slen <= limit;
// umax(offset+slen, limit) == limit is a sufficient (but not necessary
// condition)
const SCEV *MaxL = SE->getUMaxExpr(SLen, Limit);
if (MaxL != Limit) {
DEBUG(dbgs() << "MaxL != Limit: " << *MaxL << ", " << *Limit << "\n");
valid &= insertCheck(SLen, Limit, I, false);
}
//TODO: nullpointer check
const SCEV *Max = SE->getUMaxExpr(OffsetP, Limit);
if (Max == Limit)
return valid;
DEBUG(dbgs() << "Max != Limit: " << *Max << ", " << *Limit << "\n");
// check that offset < limit
valid &= insertCheck(OffsetP, Limit, I, true);
return valid;
}
bool validateAccess(Value *Pointer, unsigned size, Instruction *I)
{
return validateAccess(Pointer,
ConstantInt::get(Type::getInt32Ty(Pointer->getContext()),
size), I);
}
};
char PtrVerifier::ID;
}
llvm::Pass *createClamBCRTChecks()
{
return new PtrVerifier();
}