//
// Method: getDSNodeHandle()
//
// Description:
// This method looks up the DSNodeHandle for a given LLVM value. The context
// of the value is the specified function, although if it is a global value,
// the DSNodeHandle may exist within the global DSGraph.
//
// Return value:
// A DSNodeHandle for the value is returned. This DSNodeHandle could either
// be in the function's DSGraph or from the GlobalsGraph. Note that the
// DSNodeHandle may represent a NULL DSNode.
//
DSNodeHandle
CompleteChecks::getDSNodeHandle (const Value * V, const Function * F) {
//
// Get access to the points-to results.
//
EQTDDataStructures & dsaPass = getAnalysis<EQTDDataStructures>();
//
// Ensure that the function has a DSGraph
//
assert (dsaPass.hasDSGraph(*F) && "No DSGraph for function!\n");
//
// Lookup the DSNode for the value in the function's DSGraph.
//
DSGraph * TDG = dsaPass.getDSGraph(*F);
DSNodeHandle DSH = TDG->getNodeForValue(V);
//
// If the value wasn't found in the function's DSGraph, then maybe we can
// find the value in the globals graph.
//
if ((DSH.isNull()) && (isa<GlobalValue>(V))) {
//
// Try looking up this DSNode value in the globals graph. Note that
// globals are put into equivalence classes; we may need to first find the
// equivalence class to which our global belongs, find the global that
// represents all globals in that equivalence class, and then look up the
// DSNode Handle for *that* global.
//
DSGraph * GlobalsGraph = TDG->getGlobalsGraph ();
DSH = GlobalsGraph->getNodeForValue(V);
if (DSH.isNull()) {
//
// DSA does not currently handle global aliases.
//
if (!isa<GlobalAlias>(V)) {
//
// We have to dig into the globalEC of the DSGraph to find the DSNode.
//
const GlobalValue * GV = dyn_cast<GlobalValue>(V);
const GlobalValue * Leader;
Leader = GlobalsGraph->getGlobalECs().getLeaderValue(GV);
DSH = GlobalsGraph->getNodeForValue(Leader);
}
}
}
return DSH;
}
void GraphBuilder::visitLoadInst(LoadInst &LI) {
//
// Create a DSNode for the pointer dereferenced by the load. If the DSNode
// is NULL, do nothing more (this can occur if the load is loading from a
// NULL pointer constant (bugpoint can generate such code).
//
DSNodeHandle Ptr = getValueDest(LI.getPointerOperand());
if (Ptr.isNull()) return; // Load from null
// Make that the node is read from...
Ptr.getNode()->setReadMarker();
// Ensure a typerecord exists...
Ptr.getNode()->growSizeForType(LI.getType(), Ptr.getOffset());
if (isa<PointerType>(LI.getType()))
setDestTo(LI, getLink(Ptr));
// check that it is the inserted value
if(TypeInferenceOptimize)
if(LI.hasOneUse())
if(StoreInst *SI = dyn_cast<StoreInst>(*(LI.use_begin())))
if(SI->getOperand(0) == &LI) {
++NumIgnoredInst;
return;
}
Ptr.getNode()->mergeTypeInfo(LI.getType(), Ptr.getOffset());
}
void DSMonitor::witness(DSNodeHandle N, std::vector<Value*> VS, std::string M) {
if (N.isNull() || N.getNode()->isCollapsedNode())
return;
watch(N,VS,M);
check();
}
// Method: getDSNodeHandle()
//
// Description:
// This method looks up the DSNodeHandle for a given LLVM value. The context
// of the value is the specified function, although if it is a global value,
// the DSNodeHandle may exist within the global DSGraph.
//
// Return value:
// A DSNodeHandle for the value is returned. This DSNodeHandle could either
// be in the function's DSGraph or from the GlobalsGraph. Note that the
// DSNodeHandle may represent a NULL DSNode.
//
template<class dsa> DSNodeHandle
TypeSafety<dsa>::getDSNodeHandle (const Value * V, const Function * F) {
//
// Ensure that the function has a DSGraph
//
assert (dsaPass->hasDSGraph(*F) && "No DSGraph for function!\n");
//
// Lookup the DSNode for the value in the function's DSGraph.
//
const DSGraph * TDG = dsaPass->getDSGraph(*F);
DSNodeHandle DSH;
if(TDG->hasNodeForValue(V))
DSH = TDG->getNodeForValue(V);
//
// If the value wasn't found in the function's DSGraph, then maybe we can
// find the value in the globals graph.
//
if ((DSH.isNull()) && (isa<GlobalValue>(V))) {
//
// Try looking up this DSNode value in the globals graph. Note that
// globals are put into equivalence classes; we may need to first find the
// equivalence class to which our global belongs, find the global that
// represents all globals in that equivalence class, and then look up the
// DSNode Handle for *that* global.
//
DSH = getDSNodeHandle(cast<GlobalValue>(V));
}
return DSH;
}
// Method: getDSNodeHandle()
//
// Description:
// This method looks up the DSNodeHandle for a given LLVM globalvalue.
// The value is looked up in the globals graph
//
// Return value:
// A DSNodeHandle for the value is returned. This DSNodeHandle is from
// the GlobalsGraph. Note that the DSNodeHandle may represent a NULL DSNode.
//
template<class dsa> DSNodeHandle
TypeSafety<dsa>::getDSNodeHandle(const GlobalValue *V) {
DSNodeHandle DSH;
const DSGraph * GlobalsGraph = dsaPass->getGlobalsGraph ();
if(GlobalsGraph->hasNodeForValue(V)) {
DSH = GlobalsGraph->getNodeForValue(V);
}
//
// Try looking up this DSNode value in the globals graph. Note that
// globals are put into equivalence classes; we may need to first find the
// equivalence class to which our global belongs, find the global that
// represents all globals in that equivalence class, and then look up the
// DSNode Handle for *that* global.
//
if (DSH.isNull()) {
//
// DSA does not currently handle global aliases.
//
if (!isa<GlobalAlias>(V)) {
//
// We have to dig into the globalEC of the DSGraph to find the DSNode.
//
const GlobalValue * GV = dyn_cast<GlobalValue>(V);
const GlobalValue * Leader;
Leader = GlobalsGraph->getGlobalECs().getLeaderValue(GV);
DSH = GlobalsGraph->getNodeForValue(Leader);
}
}
return DSH;
}
void GraphBuilder::visitVAArgInst(VAArgInst &I) {
Module *M = FB->getParent();
Triple TargetTriple(M->getTargetTriple());
Triple::ArchType Arch = TargetTriple.getArch();
switch(Arch) {
case Triple::x86_64: {
// On x86_64, we have va_list as a struct {i32, i32, i8*, i8* }
// The first i8* is where arguments generally go, but the second i8* can
// be used also to pass arguments by register.
// We model this by having both the i8*'s point to an array of pointers
// to the arguments.
DSNodeHandle Ptr = G.getVANodeFor(*FB);
DSNodeHandle Dest = getValueDest(&I);
if (Ptr.isNull()) return;
// Make that the node is read and written
Ptr.getNode()->setReadMarker()->setModifiedMarker();
// Not updating type info, as it is already a collapsed node
if (isa<PointerType>(I.getType()))
Dest.mergeWith(Ptr);
return;
}
default: {
assert(0 && "What frontend generates this?");
DSNodeHandle Ptr = getValueDest(I.getOperand(0));
//FIXME: also updates the argument
if (Ptr.isNull()) return;
// Make that the node is read and written
Ptr.getNode()->setReadMarker()->setModifiedMarker();
// Ensure a type record exists.
DSNode *PtrN = Ptr.getNode();
PtrN->mergeTypeInfo(I.getType(), Ptr.getOffset());
if (isa<PointerType>(I.getType()))
setDestTo(I, getLink(Ptr));
}
}
}
void
PoolRegisterElimination::removeTypeSafeRegistrations (const char * name) {
//
// Scan through all uses of the registration function and see if it can be
// safely removed. If so, schedule it for removal.
//
std::vector<CallInst*> toBeRemoved;
Function * F = intrinsic->getIntrinsic(name).F;
//
// Look for and record all registrations that can be deleted.
//
for (Value::use_iterator UI=F->use_begin(), UE=F->use_end();
UI != UE;
++UI) {
//
// Get the pointer to the registered object.
//
CallInst * CI = cast<CallInst>(*UI);
Value * Ptr = intrinsic->getValuePointer(CI);
// Lookup the DSNode for the value in the function's DSGraph.
//
DSGraph * TDG = dsaPass->getDSGraph(*(CI->getParent()->getParent()));
DSNodeHandle DSH = TDG->getNodeForValue(Ptr);
assert ((!(DSH.isNull())) && "No DSNode for Value!\n");
//
// If the DSNode is type-safe and is never used as an array, then there
// will never be a need to look it up in a splay tree, so remove its
// registration.
//
DSNode * N = DSH.getNode();
if(!N->isArrayNode() &&
TS->isTypeSafe(Ptr, F)){
toBeRemoved.push_back(CI);
}
}
//
// Update the statistics.
//
if (toBeRemoved.size()) {
RemovedRegistration += toBeRemoved.size();
TypeSafeRegistrations += toBeRemoved.size();
}
//
// Remove the unnecesary registrations.
//
std::vector<CallInst*>::iterator it, end;
for (it = toBeRemoved.begin(), end = toBeRemoved.end(); it != end; ++it) {
(*it)->eraseFromParent();
}
}
void GraphBuilder::visitAtomicCmpXchgInst(AtomicCmpXchgInst &I) {
if (isa<PointerType>(I.getType())) {
visitInstruction (I);
return;
}
//
// Create a DSNode for the dereferenced pointer . If the DSNode is NULL, do
// nothing more (this can occur if the pointer is a NULL constant; bugpoint
// can generate such code).
//
DSNodeHandle Ptr = getValueDest(I.getPointerOperand());
if (Ptr.isNull()) return;
//
// Make that the memory object is read and written.
//
Ptr.getNode()->setReadMarker();
Ptr.getNode()->setModifiedMarker();
//
// If the result of the compare-and-swap is a pointer, then we need to do
// a few things:
// o Merge the compare and swap values (which are pointers) with the result
// o Merge the DSNode of the pointer *within* the memory object with the
// DSNode of the compare, swap, and result DSNode.
//
if (isa<PointerType>(I.getType())) {
//
// Get the DSNodeHandle of the memory object returned from the load. Make
// it the DSNodeHandle of the instruction's result.
//
DSNodeHandle FieldPtr = getLink (Ptr);
setDestTo(I, getLink(Ptr));
//
// Merge the result, compare, and swap values of the instruction.
//
FieldPtr.mergeWith (getValueDest (I.getCompareOperand()));
FieldPtr.mergeWith (getValueDest (I.getNewValOperand()));
}
//
// Modify the DSNode so that it has the loaded/written type at the
// appropriate offset.
//
Ptr.getNode()->growSizeForType(I.getType(), Ptr.getOffset());
Ptr.getNode()->mergeTypeInfo(I.getType(), Ptr.getOffset());
return;
}
//
// TODO
//
template<class dsa> bool
TypeSafety<dsa>::isFieldDisjoint (const GlobalValue * V, unsigned offset) {
//
// Get the DSNode for the specified value.
//
DSNodeHandle DH = getDSNodeHandle (V);
DSNode *node = DH.getNode();
//unsigned offset = DH.getOffset();
DEBUG(errs() << " check fields overlap at: " << offset << "\n");
//
// If there is no DSNode, claim that it is not type safe.
//
if (DH.isNull()) {
return false;
}
//
// If the DSNode is completely folded, then we know for sure that it is not
// type-safe.
//
if (node->isNodeCompletelyFolded())
return false;
//
// If the memory object represented by this DSNode can be manipulated by
// external code or DSA has otherwise not finished analyzing all operations
// on it, declare it type-unsafe.
//
if (node->isExternalNode() || node->isIncompleteNode())
return false;
//
// If the pointer to the memory object came from some source not understood
// by DSA or somehow came from/escapes to the realm of integers, declare it
// type-unsafe.
//
if (node->isUnknownNode() || node->isIntToPtrNode() || node->isPtrToIntNode()) {
return false;
}
return !((NodeInfo[node])[offset]);
}
template<class dsa> bool
TypeSafety<dsa>::isTypeSafe(const GlobalValue *V) {
//
// Get the DSNode for the specified value.
//
DSNodeHandle DH = getDSNodeHandle(V);
//
// If there is no DSNode, claim that it is not typesafe.
//
if (DH.isNull())
return false;
//
// See if the DSNode is one that we think is type-safe.
//
if (TypeSafeNodes.count (DH.getNode()))
return true;
return false;
}
void DSMonitor::watch(DSNodeHandle N, std::vector<Value*> VS, std::string M) {
if (N.isNull() || N.getNode()->isCollapsedNode()) {
unwatch();
return;
}
this->N = N;
this->VS = VS;
this->message = M;
DSGraph *G = N.getNode()->getParentGraph();
caption = getCaption(N.getNode(), G);
if (!VS.empty()) {
Instruction *I = getInstruction(VS[0]);
if (I && I->getMetadata("dbg")) {
const DebugLoc DL = I->getDebugLoc();
auto *scope = cast<DIScope>(DL.getScope());
location = scope->getFilename().str() + ":"
+ std::to_string(DL.getLine()) + ":"
+ std::to_string(DL.getCol());
}
}
}
void initialize(const Module *M, const DataStructures *DS) {
parseValue(M);
assert(V && "Failed to parse value?");
if (isa<GlobalValue>(V)) {
DSGraph *G = DS->getGlobalsGraph();
assert(G->hasNodeForValue(V) && "Node not in specified graph!");
NH = G->getNodeForValue(V);
} else {
assert(F && "No function?");
DSGraph *G = DS->getDSGraph(*F);
assert(G->hasNodeForValue(V) && "Node not in specified graph!");
NH = G->getNodeForValue(V);
}
// Handle offsets, if any
// For each offset in the offsets vector, follow the link at that offset
for (OffsetVectorTy::const_iterator I = offsets.begin(), E = offsets.end();
I != E; ++I ) {
assert(!NH.isNull() && "Null NodeHandle?");
assert(NH.hasLink(*I) && "Handle doesn't have link?");
// Follow the offset
NH = NH.getLink(*I);
}
}
void GraphBuilder::visitStoreInst(StoreInst &SI) {
Type *StoredTy = SI.getOperand(0)->getType();
DSNodeHandle Dest = getValueDest(SI.getOperand(1));
if (Dest.isNull()) return;
// Mark that the node is written to...
Dest.getNode()->setModifiedMarker();
// Ensure a type-record exists...
Dest.getNode()->growSizeForType(StoredTy, Dest.getOffset());
// Avoid adding edges from null, or processing non-"pointer" stores
if (isa<PointerType>(StoredTy))
Dest.addEdgeTo(getValueDest(SI.getOperand(0)));
if(TypeInferenceOptimize)
if(SI.getOperand(0)->hasOneUse())
if(isa<LoadInst>(SI.getOperand(0))){
++NumIgnoredInst;
return;
}
Dest.getNode()->mergeTypeInfo(StoredTy, Dest.getOffset());
}
void GraphBuilder::visitAtomicRMWInst(AtomicRMWInst &I) {
//
// Create a DSNode for the dereferenced pointer . If the DSNode is NULL, do
// nothing more (this can occur if the pointer is a NULL constant; bugpoint
// can generate such code).
//
DSNodeHandle Ptr = getValueDest(I.getPointerOperand());
if (Ptr.isNull()) return;
//
// Make that the memory object is read and written.
//
Ptr.getNode()->setReadMarker();
Ptr.getNode()->setModifiedMarker();
//
// Modify the DSNode so that it has the loaded/written type at the
// appropriate offset.
//
Ptr.getNode()->growSizeForType(I.getType(), Ptr.getOffset());
Ptr.getNode()->mergeTypeInfo(I.getType(), Ptr.getOffset());
return;
}
void
PoolRegisterElimination::removeSingletonRegistrations (const char * name) {
//
// Scan through all uses of the registration function and see if it can be
// safely removed. If so, schedule it for removal.
//
std::vector<CallInst*> toBeRemoved;
Function * F = intrinsic->getIntrinsic(name).F;
//
// Look for and record all registrations that can be deleted.
//
for (Value::use_iterator UI=F->use_begin(), UE=F->use_end();
UI != UE;
++UI) {
//
// Get the pointer to the registered object.
//
CallInst * CI = cast<CallInst>(*UI);
Value * Ptr = intrinsic->getValuePointer(CI);
//
// Lookup the DSNode for the value in the function's DSGraph.
//
DSGraph * TDG = dsaPass->getDSGraph(*(CI->getParent()->getParent()));
DSNodeHandle DSH = TDG->getNodeForValue(Ptr);
assert ((!(DSH.isNull())) && "No DSNode for Value!\n");
//
// If the object being registered is the same size as that found in the
// DSNode, then we know it's a singleton object. The run-time doesn't need
// such objects registered in the splay trees, so we can remove the
// registration function.
//
DSNode * N = DSH.getNode();
Value * Size = intrinsic->getObjectSize (Ptr->stripPointerCasts());
if (Size) {
if (ConstantInt * C = dyn_cast<ConstantInt>(Size)) {
unsigned long size = C->getZExtValue();
if (size == N->getSize()) {
toBeRemoved.push_back(CI);
continue;
}
}
}
}
//
// Update the statistics.
//
if (toBeRemoved.size()) {
RemovedRegistration += toBeRemoved.size();
SingletonRegistrations += toBeRemoved.size();
}
//
// Remove the unnecesary registrations.
//
std::vector<CallInst*>::iterator it, end;
for (it = toBeRemoved.begin(), end = toBeRemoved.end(); it != end; ++it) {
(*it)->eraseFromParent();
}
}
void GraphBuilder::visitCallSite(CallSite CS) {
//
// Get the called value. Strip off any casts which are lossless.
//
Value *Callee = CS.getCalledValue()->stripPointerCasts();
// Special case handling of certain libc allocation functions here.
if (Function *F = dyn_cast<Function>(Callee))
if (F->isIntrinsic() && visitIntrinsic(CS, F))
return;
//Can't do much about inline asm (yet!)
if (isa<InlineAsm> (Callee)) {
++NumAsmCall;
DSNodeHandle RetVal;
Instruction *I = CS.getInstruction();
if (isa<PointerType > (I->getType()))
RetVal = getValueDest(I);
// Calculate the arguments vector...
for (CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end(); I != E; ++I)
if (isa<PointerType > ((*I)->getType()))
RetVal.mergeWith(getValueDest(*I));
if (!RetVal.isNull())
RetVal.getNode()->foldNodeCompletely();
return;
}
// Set up the return value...
DSNodeHandle RetVal;
Instruction *I = CS.getInstruction();
if (isa<PointerType>(I->getType()))
RetVal = getValueDest(I);
DSNode *CalleeNode = 0;
if (!isa<Function>(Callee)) {
CalleeNode = getValueDest(Callee).getNode();
if (CalleeNode == 0) {
DEBUG(errs() << "WARNING: Program is calling through a null pointer?\n" << *I);
return; // Calling a null pointer?
}
}
// NOTE: This code is identical to 'DSGraph::getDSCallSiteForCallSite',
// the reason it's duplicated is because this calls getValueDest instead
// of getNodeForValue to get the DSNodes for the arguments. Since we're in
// local it's possible that we need to create a DSNode for the argument, as
// opposed to getNodeForValue which simply retrieves the existing node.
//Get the FunctionType for the called function
const FunctionType *CalleeFuncType = DSCallSite::FunctionTypeOfCallSite(CS);
int NumFixedArgs = CalleeFuncType->getNumParams();
// Sanity check--this really, really shouldn't happen
if (!CalleeFuncType->isVarArg())
assert(CS.arg_size() == static_cast<unsigned>(NumFixedArgs) &&
"Too many arguments/incorrect function signature!");
std::vector<DSNodeHandle> Args;
Args.reserve(CS.arg_end()-CS.arg_begin());
DSNodeHandle VarArgNH;
// Calculate the arguments vector...
// Add all fixed pointer arguments, then merge the rest together
for (CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end();
I != E; ++I)
if (isa<PointerType>((*I)->getType())) {
DSNodeHandle ArgNode = getValueDest(*I);
if (I - CS.arg_begin() < NumFixedArgs) {
Args.push_back(ArgNode);
} else {
VarArgNH.mergeWith(ArgNode);
}
}
// Add a new function call entry...
if (CalleeNode) {
++NumIndirectCall;
G.getFunctionCalls().push_back(DSCallSite(CS, RetVal, VarArgNH, CalleeNode,
Args));
} else {
++NumDirectCall;
G.getFunctionCalls().push_back(DSCallSite(CS, RetVal, VarArgNH,
cast<Function>(Callee),
Args));
}
}
void GraphBuilder::visitGetElementPtrInst(User &GEP) {
//
// Ensure that the indexed pointer has a DSNode.
//
DSNodeHandle Value = getValueDest(GEP.getOperand(0));
if (Value.isNull())
Value = createNode();
//
// There are a few quick and easy cases to handle. If the DSNode of the
// indexed pointer is already folded, then we know that the result of the
// GEP will have the same offset into the same DSNode
// as the indexed pointer.
//
if (!Value.isNull() &&
Value.getNode()->isNodeCompletelyFolded()) {
setDestTo(GEP, Value);
return;
}
//
// Okay, no easy way out. Calculate the offset into the object being
// indexed.
//
int Offset = 0;
// FIXME: I am not sure if the code below is completely correct (especially
// if we start doing fancy analysis on non-constant array indices).
// What if the array is indexed using a larger index than its declared
// size? Does the LLVM verifier catch such issues?
//
//
// Determine the offset (in bytes) between the result of the GEP and the
// GEP's pointer operand.
//
// Note: All of these subscripts are indexing INTO the elements we have...
//
// FIXME: We can do better for array indexing. First, if the array index is
// constant, we can determine how much farther we're moving the
// pointer. Second, we can try to use the results of other analysis
// passes (e.g., ScalarEvolution) to find min/max values to do less
// conservative type-folding.
//
for (gep_type_iterator I = gep_type_begin(GEP), E = gep_type_end(GEP);
I != E; ++I)
if (StructType *STy = dyn_cast<StructType>(*I)) {
// indexing into a structure
// next index must be a constant
const ConstantInt* CUI = cast<ConstantInt>(I.getOperand());
int FieldNo = CUI->getSExtValue();
// increment the offset by the actual byte offset being accessed
unsigned requiredSize = TD.getTypeAllocSize(STy) + Value.getOffset() + Offset;
if(!Value.getNode()->isArrayNode() || Value.getNode()->getSize() <= 0){
if (requiredSize > Value.getNode()->getSize())
Value.getNode()->growSize(requiredSize);
}
Offset += (unsigned)TD.getStructLayout(STy)->getElementOffset(FieldNo);
if(TypeInferenceOptimize) {
if(ArrayType* AT = dyn_cast<ArrayType>(STy->getTypeAtIndex(FieldNo))) {
Value.getNode()->mergeTypeInfo(AT, Value.getOffset() + Offset);
if((++I) == E) {
break;
}
// Check if we are still indexing into an array.
// We only record the topmost array type of any nested array.
// Keep skipping indexes till we reach a non-array type.
// J is the type of the next index.
// Uncomment the line below to get all the nested types.
gep_type_iterator J = I;
while(isa<ArrayType>(*(++J))) {
// Value.getNode()->mergeTypeInfo(AT1, Value.getOffset() + Offset);
if((++I) == E) {
break;
}
J = I;
}
if((I) == E) {
break;
}
}
}
} else if(ArrayType *ATy = dyn_cast<ArrayType>(*I)) {
// indexing into an array.
Value.getNode()->setArrayMarker();
Type *CurTy = ATy->getElementType();
if(!isa<ArrayType>(CurTy) &&
Value.getNode()->getSize() <= 0) {
Value.getNode()->growSize(TD.getTypeAllocSize(CurTy));
} else if(isa<ArrayType>(CurTy) && Value.getNode()->getSize() <= 0){
Type *ETy = (cast<ArrayType>(CurTy))->getElementType();
while(isa<ArrayType>(ETy)) {
ETy = (cast<ArrayType>(ETy))->getElementType();
}
Value.getNode()->growSize(TD.getTypeAllocSize(ETy));
}
// Find if the DSNode belongs to the array
// If not fold.
if((Value.getOffset() || Offset != 0)
|| (!isa<ArrayType>(CurTy)
&& (Value.getNode()->getSize() != TD.getTypeAllocSize(CurTy)))) {
Value.getNode()->foldNodeCompletely();
Value.getNode();
Offset = 0;
break;
}
} else if (const PointerType *PtrTy = dyn_cast<PointerType>(*I)) {
Type *CurTy = PtrTy->getElementType();
//
// Unless we're advancing the pointer by zero bytes via array indexing,
// fold the node (i.e., mark it type-unknown) and indicate that we're
// indexing zero bytes into the object.
//
// Note that we break out of the loop if we fold the node. Once
// something is folded, all values within it are considered to alias.
//
if (!isa<Constant>(I.getOperand()) ||
!cast<Constant>(I.getOperand())->isNullValue()) {
Value.getNode()->setArrayMarker();
if(!isa<ArrayType>(CurTy) && Value.getNode()->getSize() <= 0){
Value.getNode()->growSize(TD.getTypeAllocSize(CurTy));
} else if(isa<ArrayType>(CurTy) && Value.getNode()->getSize() <= 0){
Type *ETy = (cast<ArrayType>(CurTy))->getElementType();
while(isa<ArrayType>(ETy)) {
ETy = (cast<ArrayType>(ETy))->getElementType();
}
Value.getNode()->growSize(TD.getTypeAllocSize(ETy));
}
if(Value.getOffset() || Offset != 0
|| (!isa<ArrayType>(CurTy)
&& (Value.getNode()->getSize() != TD.getTypeAllocSize(CurTy)))) {
Value.getNode()->foldNodeCompletely();
Value.getNode();
Offset = 0;
break;
}
}
}
// Add in the offset calculated...
Value.setOffset(Value.getOffset()+Offset);
// Check the offset
DSNode *N = Value.getNode();
if (N) N->checkOffsetFoldIfNeeded(Value.getOffset());
// Value is now the pointer we want to GEP to be...
setDestTo(GEP, Value);
}
void GraphBuilder::visitBitCastInst(BitCastInst &I) {
if (!isa<PointerType>(I.getType())) return; // Only pointers
DSNodeHandle Ptr = getValueDest(I.getOperand(0));
if (Ptr.isNull()) return;
setDestTo(I, Ptr);
}