//
// Method: visitGetElementPtrInst()
//
// Description:
// This method checks to see if the specified GEP is safe. If it cannot prove
// it safe, it then adds a run-time check for it.
//
void
InsertGEPChecks::visitGetElementPtrInst (GetElementPtrInst & GEP) {
//
// Don't insert a check if GEP only indexes into a structure and the
// user doesn't want to do structure index checking.
//
if (DisableStructChecks && indexesStructsOnly (&GEP)) {
return;
}
//
// Get the function in which the GEP instruction lives.
//
Value * PH = ConstantPointerNull::get (getVoidPtrType(GEP.getContext()));
BasicBlock::iterator InsertPt = &GEP;
++InsertPt;
Instruction * ResultPtr = castTo (&GEP,
getVoidPtrType(GEP.getContext()),
GEP.getName() + ".cast",
InsertPt);
//
// Make this an actual cast instruction; it will make it easier to update
// DSA.
//
Value * SrcPtr = castTo (GEP.getPointerOperand(),
getVoidPtrType(GEP.getContext()),
GEP.getName()+".cast",
InsertPt);
//
// Create the call to the run-time check.
//
std::vector<Value *> args(1, PH);
args.push_back (SrcPtr);
args.push_back (ResultPtr);
CallInst * CI = CallInst::Create (PoolCheckArrayUI, args, "", InsertPt);
//
// Add debugging info metadata to the run-time check.
//
if (MDNode * MD = GEP.getMetadata ("dbg"))
CI->setMetadata ("dbg", MD);
//
// Update the statistics.
//
++GEPChecks;
return;
}
