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;
}
void GraphBuilder::visitInsertValueInst(InsertValueInst& I) {
setDestTo(I, createNode()->setAllocaMarker());
Type *StoredTy = I.getInsertedValueOperand()->getType();
DSNodeHandle Dest = getValueDest(&I);
Dest.mergeWith(getValueDest(I.getAggregateOperand()));
// Mark that the node is written to...
Dest.getNode()->setModifiedMarker();
unsigned Offset = 0;
Type* STy = I.getAggregateOperand()->getType();
llvm::InsertValueInst::idx_iterator i = I.idx_begin(), e = I.idx_end();
for (; i != e; i++) {
const StructLayout *SL = TD.getStructLayout(cast<StructType>(STy));
Offset += SL->getElementOffset(*i);
STy = (cast<StructType>(STy))->getTypeAtIndex(*i);
}
// Ensure a type-record exists...
Dest.getNode()->mergeTypeInfo(StoredTy, Offset);
// Avoid adding edges from null, or processing non-"pointer" stores
if (isa<PointerType>(StoredTy))
Dest.addEdgeTo(getValueDest(I.getInsertedValueOperand()));
}
// visitInstruction - For all other instruction types, if we have any arguments
// that are of pointer type, make them have unknown composition bits, and merge
// the nodes together.
void GraphBuilder::visitInstruction(Instruction &Inst) {
DSNodeHandle CurNode;
if (isa<PointerType>(Inst.getType()))
CurNode = getValueDest(&Inst);
for (User::op_iterator I = Inst.op_begin(), E = Inst.op_end(); I != E; ++I)
if (isa<PointerType>((*I)->getType()))
CurNode.mergeWith(getValueDest(*I));
if (DSNode *N = CurNode.getNode())
N->setUnknownMarker();
}
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));
}
}
}
/// ResolveFunctionCall - Resolve the actual arguments of a call to function F
/// with the specified call site descriptor. This function links the arguments
/// and the return value for the call site context-insensitively.
///
void
SteensgaardDataStructures::ResolveFunctionCall(const Function *F,
const DSCallSite &Call,
DSNodeHandle &RetVal) {
assert(ResultGraph != 0 && "Result graph not allocated!");
DSGraph::ScalarMapTy &ValMap = ResultGraph->getScalarMap();
// Handle the return value of the function...
if (Call.getRetVal().getNode() && RetVal.getNode())
RetVal.mergeWith(Call.getRetVal());
// Loop over all pointer arguments, resolving them to their provided pointers
unsigned PtrArgIdx = 0;
for (Function::const_arg_iterator AI = F->arg_begin(), AE = F->arg_end();
AI != AE && PtrArgIdx < Call.getNumPtrArgs(); ++AI) {
DSGraph::ScalarMapTy::iterator I = ValMap.find(AI);
if (I != ValMap.end()) // If its a pointer argument...
I->second.mergeWith(Call.getPtrArg(PtrArgIdx++));
}
}
///
/// Method: visitIntrinsic()
///
/// Description:
/// Generate correct DSNodes for calls to LLVM intrinsic functions.
///
/// Inputs:
/// CS - The CallSite representing the call or invoke to the intrinsic.
/// F - A pointer to the function called by the call site.
///
/// Return value:
/// true - This intrinsic is properly handled by this method.
/// false - This intrinsic is not recognized by DSA.
///
bool GraphBuilder::visitIntrinsic(CallSite CS, Function *F) {
++NumIntrinsicCall;
//
// If this is a debug intrinsic, then don't do any special processing.
//
if (isa<DbgInfoIntrinsic>(CS.getInstruction()))
return true;
switch (F->getIntrinsicID()) {
case Intrinsic::vastart: {
visitVAStartInst(CS);
return true;
}
case Intrinsic::vacopy: {
// Simply merge the two arguments to va_copy.
// This results in loss of precision on the temporaries used to manipulate
// the va_list, and so isn't a big deal. In theory we would build a
// separate graph for this (like the one created in visitVAStartNode)
// and only merge the node containing the variable arguments themselves.
DSNodeHandle destNH = getValueDest(CS.getArgument(0));
DSNodeHandle srcNH = getValueDest(CS.getArgument(1));
destNH.mergeWith(srcNH);
return true;
}
case Intrinsic::stacksave: {
DSNode * Node = createNode();
Node->setAllocaMarker()->setIncompleteMarker()->setUnknownMarker();
Node->foldNodeCompletely();
setDestTo (*(CS.getInstruction()), Node);
return true;
}
case Intrinsic::stackrestore:
getValueDest(CS.getInstruction()).getNode()->setAllocaMarker()
->setIncompleteMarker()
->setUnknownMarker()
->foldNodeCompletely();
return true;
case Intrinsic::vaend:
case Intrinsic::memcpy:
case Intrinsic::memmove: {
// Merge the first & second arguments, and mark the memory read and
// modified.
DSNodeHandle RetNH = getValueDest(*CS.arg_begin());
RetNH.mergeWith(getValueDest(*(CS.arg_begin()+1)));
if (DSNode *N = RetNH.getNode())
N->setModifiedMarker()->setReadMarker();
return true;
}
case Intrinsic::memset:
// Mark the memory modified.
if (DSNode *N = getValueDest(*CS.arg_begin()).getNode())
N->setModifiedMarker();
return true;
case Intrinsic::eh_exception: {
DSNode * Node = createNode();
Node->setIncompleteMarker();
Node->foldNodeCompletely();
setDestTo (*(CS.getInstruction()), Node);
return true;
}
case Intrinsic::eh_selector: {
for (CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end();
I != E; ++I) {
if (isa<PointerType>((*I)->getType())) {
DSNodeHandle Ptr = getValueDest(*I);
if(Ptr.getNode()) {
Ptr.getNode()->setReadMarker();
Ptr.getNode()->setIncompleteMarker();
}
}
}
return true;
}
case Intrinsic::eh_typeid_for: {
DSNodeHandle Ptr = getValueDest(*CS.arg_begin());
Ptr.getNode()->setReadMarker();
Ptr.getNode()->setIncompleteMarker();
return true;
}
case Intrinsic::prefetch:
return true;
case Intrinsic::objectsize:
return true;
//
// The return address/frame address aliases with the stack,
// is type-unknown, and should
// have the unknown flag set since we don't know where it goes.
//
case Intrinsic::returnaddress:
case Intrinsic::frameaddress: {
DSNode * Node = createNode();
Node->setAllocaMarker()->setIncompleteMarker()->setUnknownMarker();
Node->foldNodeCompletely();
setDestTo (*(CS.getInstruction()), Node);
return true;
}
// Process lifetime intrinsics
case Intrinsic::lifetime_start:
case Intrinsic::lifetime_end:
case Intrinsic::invariant_start:
case Intrinsic::invariant_end:
return true;
default: {
//ignore pointer free intrinsics
if (!isa<PointerType>(F->getReturnType())) {
bool hasPtr = false;
for (Function::const_arg_iterator I = F->arg_begin(), E = F->arg_end();
I != E && !hasPtr; ++I)
if (isa<PointerType>(I->getType()))
hasPtr = true;
if (!hasPtr)
return true;
}
DEBUG(errs() << "[dsa:local] Unhandled intrinsic: " << F->getName() << "\n");
assert(0 && "Unhandled intrinsic");
return false;
}
}
}
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));
}
}
