void RTAssociate::ProcessFunctionBody(Function &F, Function &NewF, DSGraph* G,
DataStructures* DS) {
if (G->node_begin() == G->node_end()) return; // Quick exit if nothing to do.
FuncInfo &FI = *getFuncInfo(&F);
// Calculate which DSNodes are reachable from globals. If a node is reachable
// from a global, we will create a global pool for it, so no argument passage
// is required.
G->getGlobalsGraph();
// Map all node reachable from this global to the corresponding nodes in
// the globals graph.
DSGraph::NodeMapTy GlobalsGraphNodeMapping;
G->computeGToGGMapping(GlobalsGraphNodeMapping);
// Loop over all of the nodes which are non-escaping, adding pool-allocatable
// ones to the NodesToPA vector.
for (DSGraph::node_iterator I = G->node_begin(), E = G->node_end(); I != E; ++I) {
DSNode *N = I;
if (GlobalsGraphNodeMapping.count(N)) {
// If it is a global pool, set up the pool descriptor appropriately.
DSNode *GGN = GlobalsGraphNodeMapping[N].getNode();
assert(getFuncInfo(0)->PoolDescriptors[GGN] && "Should be in global mapping!");
FI.PoolDescriptors[N] = getFuncInfo(0)->PoolDescriptors[GGN];
} else if (!FI.PoolDescriptors[N]) {
// Otherwise, if it was not passed in from outside the function, it must
// be a local pool!
assert(!N->isGlobalNode() && "Should be in global mapping!");
FI.PoolDescriptors[N] = CreateLocalPool(N, NewF);
}
}
TransformBody(NewF, FI, DS);
}
//
// Method: visitCallSite()
//
// Description:
// This method transforms a call site. A call site may either be a call
// instruction or an invoke instruction.
//
// Inputs:
// CS - The call site representing the instruction that should be transformed.
//
void FuncTransform::visitCallSite(CallSite& CS) {
const Function *CF = CS.getCalledFunction();
Instruction *TheCall = CS.getInstruction();
bool thread_creation_point = false;
//
// Get the value that is called at this call site. Strip away any pointer
// casts that do not change the representation of the data (i.e., are
// lossless casts).
//
Value * CalledValue = CS.getCalledValue()->stripPointerCasts();
//
// The CallSite::getCalledFunction() method is not guaranteed to strip off
// pointer casts. If no called function was found, manually strip pointer
// casts off of the called value and see if we get a function. If so, this
// is a direct call, and we want to update CF accordingly.
//
if (!CF) CF = dyn_cast<Function>(CalledValue);
//
// Do not change any inline assembly code.
//
if (isa<InlineAsm>(TheCall->getOperand(0))) {
errs() << "INLINE ASM: ignoring. Hoping that's safe.\n";
return;
}
//
// Ignore calls to NULL pointers or undefined values.
//
if ((isa<ConstantPointerNull>(CalledValue)) ||
(isa<UndefValue>(CalledValue))) {
errs() << "WARNING: Ignoring call using NULL/Undef function pointer.\n";
return;
}
// If this function is one of the memory manipulating functions built into
// libc, emulate it with pool calls as appropriate.
if (CF && CF->isDeclaration()) {
std::string Name = CF->getName();
if (Name == "free" || Name == "cfree") {
visitFreeCall(CS);
return;
} else if (Name == "malloc") {
visitMallocCall(CS);
return;
} else if (Name == "calloc") {
visitCallocCall(CS);
return;
} else if (Name == "realloc") {
visitReallocCall(CS);
return;
} else if (Name == "memalign" || Name == "posix_memalign") {
visitMemAlignCall(CS);
return;
} else if (Name == "strdup") {
visitStrdupCall(CS);
return;
} else if (Name == "valloc") {
errs() << "VALLOC USED BUT NOT HANDLED!\n";
abort();
} else if (unsigned PoolArgc = PAInfo.getNumInitialPoolArguments(Name)) {
visitRuntimeCheck(CS, PoolArgc);
return;
} else if (Name == "pthread_create") {
thread_creation_point = true;
//
// Get DSNode representing the DSNode of the function pointer Value of
// the pthread_create call
//
DSNode* thread_callee_node = G->getNodeForValue(CS.getArgument(2)).getNode();
if (!thread_callee_node) {
assert(0 && "apparently you need this code");
FuncInfo *CFI = PAInfo.getFuncInfo(*CF);
thread_callee_node = G->getNodeForValue(CFI->MapValueToOriginal(CS.getArgument(2))).getNode();
}
// Fill in CF with the name of one of the functions in thread_callee_node
CF = const_cast<Function*>(dyn_cast<Function>(*thread_callee_node->globals_begin()));
}
}
//
// We need to figure out which local pool descriptors correspond to the pool
// descriptor arguments passed into the function call. Calculate a mapping
// from callee DSNodes to caller DSNodes. We construct a partial isomophism
// between the graphs to figure out which pool descriptors need to be passed
// in. The roots of this mapping is found from arguments and return values.
//
DataStructures& Graphs = PAInfo.getGraphs();
DSGraph::NodeMapTy NodeMapping;
Instruction *NewCall;
Value *NewCallee;
std::vector<const DSNode*> ArgNodes;
DSGraph *CalleeGraph; // The callee graph
// For indirect callees, find any callee since all DS graphs have been
// merged.
if (CF) { // Direct calls are nice and simple.
DEBUG(errs() << " Handling direct call: " << *TheCall << "\n");
//
// Do not try to add pool handles to the function if it:
// a) Already calls a cloned function; or
// b) Calls a function which was never cloned.
//
// For such a call, just replace any arguments that take original functions
// with their cloned function poiner values.
//
FuncInfo *CFI = PAInfo.getFuncInfo(*CF);
if (CFI == 0 || CFI->Clone == 0) { // Nothing to transform...
visitInstruction(*TheCall);
return;
}
//
// Oh, dear. We must add pool descriptors to this direct call.
//
NewCallee = CFI->Clone;
ArgNodes = CFI->ArgNodes;
assert ((Graphs.hasDSGraph (*CF)) && "Function has no ECGraph!\n");
CalleeGraph = Graphs.getDSGraph(*CF);
} else {
DEBUG(errs() << " Handling indirect call: " << *TheCall << "\n");
DSGraph *G = Graphs.getGlobalsGraph();
DSGraph::ScalarMapTy& SM = G->getScalarMap();
// Here we fill in CF with one of the possible called functions. Because we
// merged together all of the arguments to all of the functions in the
// equivalence set, it doesn't really matter which one we pick.
// (If the function was cloned, we have to map the cloned call instruction
// in CS back to the original call instruction.)
Instruction *OrigInst =
cast<Instruction>(getOldValueIfAvailable(CS.getInstruction()));
//
// Attempt to get one of the function targets of this indirect call site by
// looking at the call graph constructed by the points-to analysis. Be
// sure to use the original call site from the original function; the
// points-to analysis has no information on the clones we've created.
//
// Also, look for the target that has the greatest number of arguments that
// have associated DSNodes. This ensures that we pass the maximum number
// of pools possible and prevents us from eliding a pool because we're
// examining a target that doesn't need it.
//
const DSCallGraph & callGraph = Graphs.getCallGraph();
DSCallGraph::callee_iterator I = callGraph.callee_begin(OrigInst);
for (; I != callGraph.callee_end(OrigInst); ++I) {
for(DSCallGraph::scc_iterator sccii = callGraph.scc_begin(*I),
sccee = callGraph.scc_end(*I); sccii != sccee; ++sccii){
if(SM.find(SM.getLeaderForGlobal(*sccii)) == SM.end())
continue;
//
// Get the information for this function. Since this is coming from
// DSA, it should be an original function.
//
// This call site calls a function, that is not defined in this module
if (!(Graphs.hasDSGraph(**sccii))) return;
// For all other cases Func Info must exist.
PAInfo.getFuncInfo(**sccii);
//
// If this target takes more DSNodes than the last one we found, then
// make *this* target our canonical target.
//
CF = *sccii;
break;
}
}
if(!CF){
const Function *F1 = OrigInst->getParent()->getParent();
F1 = callGraph.sccLeader(&*F1);
for(DSCallGraph::scc_iterator sccii = callGraph.scc_begin(F1),
sccee = callGraph.scc_end(F1); sccii != sccee; ++sccii){
if(SM.find(SM.getLeaderForGlobal(*sccii)) == SM.end())
continue;
//
// Get the information for this function. Since this is coming from DSA,
// it should be an original function.
//
// This call site calls a function, that is not defined in this module
if (!(Graphs.hasDSGraph(**sccii))) return;
// For all other cases Func Info must exist.
PAInfo.getFuncInfo(**sccii);
//
// If this target takes more DSNodes than the last one we found, then
// make *this* target our canonical target.
//
CF = *sccii;
}
}
// Assuming the call graph is always correct. And if the call graph reports,
// no callees, we can assume that it is right.
//
// If we didn't find the callee in the constructed call graph, try
// checking in the DSNode itself.
// This isn't ideal as it means that this call site didn't have inlining
// happen.
//
//
// If we still haven't been able to find a target function of the call site
// to transform, do nothing.
//
// One may be tempted to think that we should always have at least one
// target, but this is not true. There are perfectly acceptable (but
// strange) programs for which no function targets exist. Function
// pointers loaded from undef values, for example, will have no targets.
//
if (!CF) return;
//
// It's possible that this program has indirect call targets that are
// not defined in this module. Do not transformation for such functions.
//
if (!(Graphs.hasDSGraph(*CF))) return;
//
// Get the common graph for the set of functions this call may invoke.
//
assert ((Graphs.hasDSGraph(*CF)) && "Function has no DSGraph!\n");
CalleeGraph = Graphs.getDSGraph(*CF);
#ifndef NDEBUG
// Verify that all potential callees at call site have the same DS graph.
DSCallGraph::callee_iterator E = Graphs.getCallGraph().callee_end(OrigInst);
for (; I != E; ++I) {
const Function * F = *I;
assert (F);
if (!(F)->isDeclaration())
assert(CalleeGraph == Graphs.getDSGraph(**I) &&
"Callees at call site do not have a common graph!");
}
#endif
// Find the DS nodes for the arguments that need to be added, if any.
FuncInfo *CFI = PAInfo.getFuncInfo(*CF);
assert(CFI && "No function info for callee at indirect call?");
ArgNodes = CFI->ArgNodes;
if (ArgNodes.empty())
return; // No arguments to add? Transformation is a noop!
// Cast the function pointer to an appropriate type!
std::vector<Type*> ArgTys(ArgNodes.size(),
PoolAllocate::PoolDescPtrTy);
for (CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end();
I != E; ++I)
ArgTys.push_back((*I)->getType());
FunctionType *FTy = FunctionType::get(TheCall->getType(), ArgTys, false);
PointerType *PFTy = PointerType::getUnqual(FTy);
// If there are any pool arguments cast the func ptr to the right type.
NewCallee = CastInst::CreatePointerCast(CS.getCalledValue(), PFTy, "tmp", TheCall);
}
//
// FIXME: Why do we disable strict checking when calling the
// DSGraph::computeNodeMapping() method?
//
Function::const_arg_iterator FAI = CF->arg_begin(), E = CF->arg_end();
CallSite::arg_iterator AI = CS.arg_begin() + (thread_creation_point ? 3 : 0);
CallSite::arg_iterator AE = CS.arg_end();
for ( ; FAI != E && AI != AE; ++FAI, ++AI)
if (!isa<Constant>(*AI)) {
DSGraph::computeNodeMapping(CalleeGraph->getNodeForValue(FAI),
getDSNodeHFor(*AI), NodeMapping, false);
}
//assert(AI == AE && "Varargs calls not handled yet!");
// Map the return value as well...
if (isa<PointerType>(TheCall->getType()))
DSGraph::computeNodeMapping(CalleeGraph->getReturnNodeFor(*CF),
getDSNodeHFor(TheCall), NodeMapping, false);
// This code seems redundant (and crashes occasionally)
// There is no reason to map globals here, since they are not passed as
// arguments
// // Map the nodes that are pointed to by globals.
// DSScalarMap &CalleeSM = CalleeGraph->getScalarMap();
// for (DSScalarMap::global_iterator GI = G.getScalarMap().global_begin(),
// E = G.getScalarMap().global_end(); GI != E; ++GI)
// if (CalleeSM.count(*GI))
// DSGraph::computeNodeMapping(CalleeGraph->getNodeForValue(*GI),
// getDSNodeHFor(*GI),
// NodeMapping, false);
//
// Okay, now that we have established our mapping, we can figure out which
// pool descriptors to pass in...
//
// Note:
// There used to be code here that would create a new pool before the
// function call and destroy it after the function call. This could would
// get triggered if bounds checking was disbled or the DSNode for the
// argument was an array value.
//
// I believe that code was incorrect; an argument may have a NULL pool handle
// (i.e., no pool handle) because the pool allocation heuristic used simply
// decided not to assign that value a pool. The argument may alias data
// that should not be freed after the function call is complete, so calling
// pooldestroy() after the call would free data, causing dangling pointer
// dereference errors.
//
std::vector<Value*> Args;
for (unsigned i = 0, e = ArgNodes.size(); i != e; ++i) {
Value *ArgVal = Constant::getNullValue(PoolAllocate::PoolDescPtrTy);
if (NodeMapping.count(ArgNodes[i])) {
if (DSNode *LocalNode = NodeMapping[ArgNodes[i]].getNode())
if (FI.PoolDescriptors.count(LocalNode))
ArgVal = FI.PoolDescriptors.find(LocalNode)->second;
}
Args.push_back(ArgVal);
}
// Add the rest of the arguments unless we're a thread creation point, in which case we only need the pools
if(!thread_creation_point)
Args.insert(Args.end(), CS.arg_begin(), CS.arg_end());
//
// There are circumstances where a function is casted to another type and
// then called (que horible). We need to perform a similar cast if the
// type doesn't match the number of arguments.
//
if (Function * NewFunction = dyn_cast<Function>(NewCallee)) {
FunctionType * NewCalleeType = NewFunction->getFunctionType();
if (NewCalleeType->getNumParams() != Args.size()) {
std::vector<Type *> Types;
Type * FuncTy = FunctionType::get (NewCalleeType->getReturnType(),
Types,
true);
FuncTy = PointerType::getUnqual (FuncTy);
NewCallee = new BitCastInst (NewCallee, FuncTy, "", TheCall);
}
}
std::string Name = TheCall->getName(); TheCall->setName("");
if(thread_creation_point) {
Module *M = CS.getInstruction()->getParent()->getParent()->getParent();
Value* pthread_replacement = M->getFunction("poolalloc_pthread_create");
std::vector<Value*> thread_args;
//Push back original thread arguments through the callee
thread_args.push_back(CS.getArgument(0));
thread_args.push_back(CS.getArgument(1));
thread_args.push_back(CS.getArgument(2));
//Push back the integer argument saying how many uses there are
thread_args.push_back(Constant::getIntegerValue(llvm::Type::getInt32Ty(M->getContext()),APInt(32,Args.size())));
thread_args.insert(thread_args.end(),Args.begin(),Args.end());
thread_args.push_back(CS.getArgument(3));
//Make the thread creation call
NewCall = CallInst::Create(pthread_replacement,
thread_args,
Name,TheCall);
}
else if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {
NewCall = InvokeInst::Create (NewCallee, II->getNormalDest(),
II->getUnwindDest(),
Args, Name, TheCall);
} else {
NewCall = CallInst::Create (NewCallee, Args, Name,
TheCall);
}
// Add all of the uses of the pool descriptor
for (unsigned i = 0, e = ArgNodes.size(); i != e; ++i)
AddPoolUse(*NewCall, Args[i], PoolUses);
TheCall->replaceAllUsesWith(NewCall);
DEBUG(errs() << " Result Call: " << *NewCall << "\n");
if (!TheCall->getType()->isVoidTy()) {
// If we are modifying the original function, update the DSGraph...
DSGraph::ScalarMapTy &SM = G->getScalarMap();
DSGraph::ScalarMapTy::iterator CII = SM.find(TheCall);
if (CII != SM.end()) {
SM[NewCall] = CII->second;
SM.erase(CII); // Destroy the CallInst
} else if (!FI.NewToOldValueMap.empty()) {
// Otherwise, if this is a clone, update the NewToOldValueMap with the new
// CI return value.
UpdateNewToOldValueMap(TheCall, NewCall);
}
} else if (!FI.NewToOldValueMap.empty()) {
UpdateNewToOldValueMap(TheCall, NewCall);
}
//
// Copy over the calling convention and attributes of the original call
// instruction to the new call instruction.
//
CallSite(NewCall).setCallingConv(CallSite(TheCall).getCallingConv());
TheCall->eraseFromParent();
visitInstruction(*NewCall);
}
void RTAssociate::replaceCall(CallSite CS, FuncInfo& FI, DataStructures* DS) {
const Function *CF = CS.getCalledFunction();
Instruction *TheCall = CS.getInstruction();
// If the called function is casted from one function type to another, peer
// into the cast instruction and pull out the actual function being called.
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(CS.getCalledValue()))
if (CE->getOpcode() == Instruction::BitCast &&
isa<Function>(CE->getOperand(0)))
CF = cast<Function>(CE->getOperand(0));
if (isa<InlineAsm>(TheCall->getOperand(0))) {
errs() << "INLINE ASM: ignoring. Hoping that's safe.\n";
return;
}
// Ignore calls to NULL pointers.
if (isa<ConstantPointerNull>(CS.getCalledValue())) {
errs() << "WARNING: Ignoring call using NULL function pointer.\n";
return;
}
// We need to figure out which local pool descriptors correspond to the pool
// descriptor arguments passed into the function call. Calculate a mapping
// from callee DSNodes to caller DSNodes. We construct a partial isomophism
// between the graphs to figure out which pool descriptors need to be passed
// in. The roots of this mapping is found from arguments and return values.
//
DSGraph::NodeMapTy NodeMapping;
Instruction *NewCall;
Value *NewCallee;
std::vector<const DSNode*> ArgNodes;
DSGraph *CalleeGraph; // The callee graph
// For indirect callees, find any callee since all DS graphs have been
// merged.
if (CF) { // Direct calls are nice and simple.
DEBUG(errs() << " Handling direct call: " << *TheCall);
FuncInfo *CFI = getFuncInfo(CF);
if (CFI == 0 || CFI->Clone == 0) // Nothing to transform...
return;
NewCallee = CFI->Clone;
ArgNodes = CFI->ArgNodes;
assert ((DS->hasDSGraph (*CF)) && "Function has no ECGraph!\n");
CalleeGraph = DS->getDSGraph(*CF);
} else {
DEBUG(errs() << " Handling indirect call: " << *TheCall);
// Here we fill in CF with one of the possible called functions. Because we
// merged together all of the arguments to all of the functions in the
// equivalence set, it doesn't really matter which one we pick.
// (If the function was cloned, we have to map the cloned call instruction
// in CS back to the original call instruction.)
Instruction *OrigInst =
cast<Instruction>(FI.getOldValueIfAvailable(CS.getInstruction()));
DSCallGraph::callee_iterator I = DS->getCallGraph().callee_begin(CS);
if (I != DS->getCallGraph().callee_end(CS))
CF = *I;
// If we didn't find the callee in the constructed call graph, try
// checking in the DSNode itself.
// This isn't ideal as it means that this call site didn't have inlining
// happen.
if (!CF) {
DSGraph* dg = DS->getDSGraph(*OrigInst->getParent()->getParent());
DSNode* d = dg->getNodeForValue(OrigInst->getOperand(0)).getNode();
assert (d && "No DSNode!\n");
std::vector<const Function*> g;
d->addFullFunctionList(g);
if (g.size()) {
EquivalenceClasses< const GlobalValue *> & EC = dg->getGlobalECs();
for(std::vector<const Function*>::const_iterator ii = g.begin(), ee = g.end();
!CF && ii != ee; ++ii) {
for (EquivalenceClasses<const GlobalValue *>::member_iterator MI = EC.findLeader(*ii);
MI != EC.member_end(); ++MI) // Loop over members in this set.
if ((CF = dyn_cast<Function>(*MI))) {
break;
}
}
}
}
//
// Do an assert unless we're bugpointing something.
//
// if ((UsingBugpoint) && (!CF)) return;
if (!CF)
errs() << "No Graph for CallSite in "
<< TheCall->getParent()->getParent()->getName().str()
<< " originally "
<< OrigInst->getParent()->getParent()->getName().str()
<< "\n";
assert (CF && "No call graph info");
// Get the common graph for the set of functions this call may invoke.
// if (UsingBugpoint && (!(Graphs.hasDSGraph(*CF)))) return;
assert ((DS->hasDSGraph(*CF)) && "Function has no DSGraph!\n");
CalleeGraph = DS->getDSGraph(*CF);
#ifndef NDEBUG
// Verify that all potential callees at call site have the same DS graph.
DSCallGraph::callee_iterator E = DS->getCallGraph().callee_end(CS);
for (; I != E; ++I)
if (!(*I)->isDeclaration())
assert(CalleeGraph == DS->getDSGraph(**I) &&
"Callees at call site do not have a common graph!");
#endif
// Find the DS nodes for the arguments that need to be added, if any.
FuncInfo *CFI = getFuncInfo(CF);
assert(CFI && "No function info for callee at indirect call?");
ArgNodes = CFI->ArgNodes;
if (ArgNodes.empty())
return; // No arguments to add? Transformation is a noop!
// Cast the function pointer to an appropriate type!
std::vector<Type*> ArgTys(ArgNodes.size(), PoolDescPtrTy);
for (CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end();
I != E; ++I)
ArgTys.push_back((*I)->getType());
FunctionType *FTy = FunctionType::get(TheCall->getType(), ArgTys, false);
PointerType *PFTy = PointerType::getUnqual(FTy);
// If there are any pool arguments cast the func ptr to the right type.
NewCallee = CastInst::CreatePointerCast(CS.getCalledValue(), PFTy, "tmp", TheCall);
}
Function::const_arg_iterator FAI = CF->arg_begin(), E = CF->arg_end();
CallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
for ( ; FAI != E && AI != AE; ++FAI, ++AI)
if (!isa<Constant>(*AI))
DSGraph::computeNodeMapping(CalleeGraph->getNodeForValue(FAI),
FI.getDSNodeHFor(*AI), NodeMapping, false);
assert(AI == AE && "Varargs calls not handled yet!");
// Map the return value as well...
if (isa<PointerType>(TheCall->getType()))
DSGraph::computeNodeMapping(CalleeGraph->getReturnNodeFor(*CF),
FI.getDSNodeHFor(TheCall), NodeMapping, false);
// Okay, now that we have established our mapping, we can figure out which
// pool descriptors to pass in...
std::vector<Value*> Args;
for (unsigned i = 0, e = ArgNodes.size(); i != e; ++i) {
Value *ArgVal = Constant::getNullValue(PoolDescPtrTy);
if (NodeMapping.count(ArgNodes[i]))
if (DSNode *LocalNode = NodeMapping[ArgNodes[i]].getNode())
if (FI.PoolDescriptors.count(LocalNode))
ArgVal = FI.PoolDescriptors.find(LocalNode)->second;
if (isa<Constant > (ArgVal) && cast<Constant > (ArgVal)->isNullValue())
errs() << "WARNING: NULL POOL ARGUMENTS ARE PASSED IN!\n";
Args.push_back(ArgVal);
}
// Add the rest of the arguments...
Args.insert(Args.end(), CS.arg_begin(), CS.arg_end());
//
// There are circumstances where a function is casted to another type and
// then called (que horible). We need to perform a similar cast if the
// type doesn't match the number of arguments.
//
if (Function * NewFunction = dyn_cast<Function>(NewCallee)) {
FunctionType * NewCalleeType = NewFunction->getFunctionType();
if (NewCalleeType->getNumParams() != Args.size()) {
std::vector<Type *> Types;
Type * FuncTy = FunctionType::get (NewCalleeType->getReturnType(),
Types,
true);
FuncTy = PointerType::getUnqual (FuncTy);
NewCallee = new BitCastInst (NewCallee, FuncTy, "", TheCall);
}
}
std::string Name = TheCall->getName(); TheCall->setName("");
if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {
NewCall = InvokeInst::Create (NewCallee, II->getNormalDest(),
II->getUnwindDest(),
Args, Name, TheCall);
} else {
NewCall = CallInst::Create (NewCallee, Args, Name,
TheCall);
}
TheCall->replaceAllUsesWith(NewCall);
DEBUG(errs() << " Result Call: " << *NewCall);
if (TheCall->getType()->getTypeID() != Type::VoidTyID) {
// If we are modifying the original function, update the DSGraph...
DSGraph::ScalarMapTy &SM = FI.G->getScalarMap();
DSGraph::ScalarMapTy::iterator CII = SM.find(TheCall);
if (CII != SM.end()) {
SM[NewCall] = CII->second;
SM.erase(CII); // Destroy the CallInst
} else if (!FI.NewToOldValueMap.empty()) {
// Otherwise, if this is a clone, update the NewToOldValueMap with the new
// CI return value.
FI.UpdateNewToOldValueMap(TheCall, NewCall);
}
} else if (!FI.NewToOldValueMap.empty()) {
FI.UpdateNewToOldValueMap(TheCall, NewCall);
}
//FIXME: attributes on call?
CallSite(NewCall).setCallingConv(CallSite(TheCall).getCallingConv());
TheCall->eraseFromParent();
}
/// visitGraph - Visit the functions in the specified graph, updating the
/// specified lattice values for all of their uses.
///
void StructureFieldVisitorBase::
visitGraph(DSGraph &DSG, std::multimap<DSNode*, LatticeValue*> &NodeLVs) {
assert(!NodeLVs.empty() && "No lattice values to compute!");
// To visit a graph, first step, we visit the instruction making up each
// function in the graph, but ignore calls when processing them. We handle
// call nodes explicitly by looking at call nodes in the graph if needed. We
// handle instructions before calls to avoid interprocedural analysis if we
// can drive lattice values to bottom early.
//
SFVInstVisitor IV(DSG, Callbacks, NodeLVs);
for (DSGraph::retnodes_iterator FI = DSG.retnodes_begin(),
E = DSG.retnodes_end(); FI != E; ++FI)
for (Function::iterator BB = FI->first->begin(), E = FI->first->end();
BB != E; ++BB)
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
if (IV.visit(*I) && NodeLVs.empty())
return; // Nothing left to analyze.
// Keep track of which actual direct callees are handled.
std::set<Function*> CalleesHandled;
// Once we have visited all of the instructions in the function bodies, if
// there are lattice values that have not been driven to bottom, see if any of
// the nodes involved are passed into function calls. If so, we potentially
// have to recursively traverse the call graph.
for (DSGraph::fc_iterator CS = DSG.fc_begin(), E = DSG.fc_end();
CS != E; ++CS) {
// Figure out the mapping from a node in the caller (potentially several)
// nodes in the callee.
DSGraph::NodeMapTy CallNodeMap;
Instruction *TheCall = CS->getCallSite().getInstruction();
// If this is an indirect function call, assume nothing gets passed through
// it. FIXME: THIS IS BROKEN! Just get the ECG for the fn ptr if it's not
// direct.
if (CS->isIndirectCall())
continue;
// If this is an external function call, it cannot be involved with this
// node, because otherwise the node would be marked incomplete!
if (CS->getCalleeFunc()->isExternal())
continue;
// If we can handle this function call, remove it from the set of direct
// calls found by the visitor.
CalleesHandled.insert(CS->getCalleeFunc());
std::vector<DSNodeHandle> Args;
DSGraph *CG = &ECG.getDSGraph(*CS->getCalleeFunc());
CG->getFunctionArgumentsForCall(CS->getCalleeFunc(), Args);
if (!CS->getRetVal().isNull())
DSGraph::computeNodeMapping(Args[0], CS->getRetVal(), CallNodeMap);
for (unsigned i = 0, e = CS->getNumPtrArgs(); i != e; ++i) {
if (i == Args.size()-1) break;
DSGraph::computeNodeMapping(Args[i+1], CS->getPtrArg(i), CallNodeMap);
}
Args.clear();
// The mapping we just computed maps from nodes in the callee to nodes in
// the caller, so we can't query it efficiently. Instead of going through
// the trouble of inverting the map to do this (linear time with the size of
// the mapping), we just do a linear search to see if any affected nodes are
// passed into this call.
bool CallCanModifyDataFlow = false;
for (DSGraph::NodeMapTy::iterator MI = CallNodeMap.begin(),
E = CallNodeMap.end(); MI != E; ++MI)
if (NodeLVs.count(MI->second.getNode()))
// Okay, the node is passed in, check to see if the call might do
// something interesting to it (i.e. if analyzing the call can produce
// anything other than "top").
if ((CallCanModifyDataFlow = NodeCanPossiblyBeInteresting(MI->first,
Callbacks)))
break;
// If this function call cannot impact the analysis (either because the
// nodes we are tracking are not passed into the call, or the DSGraph for
// the callee tells us that analysis of the callee can't provide interesting
// information), ignore it.
if (!CallCanModifyDataFlow)
continue;
// Okay, either compute analysis results for the callee function, or reuse
// results previously computed.
std::multimap<DSNode*, LatticeValue*> &CalleeFacts = getCalleeFacts(*CG);
// Merge all of the facts for the callee into the facts for the caller. If
// this reduces anything in the caller to 'bottom', remove them.
for (DSGraph::NodeMapTy::iterator MI = CallNodeMap.begin(),
E = CallNodeMap.end(); MI != E; ++MI) {
// If we have Lattice facts in the caller for this node in the callee,
// merge any information from the callee into the caller.
// If the node is not accessed in the callee at all, don't update.
if (MI->first->getType() == Type::VoidTy)
continue;
// If there are no data-flow facts live in the caller for this node, don't
// both processing it.
std::multimap<DSNode*, LatticeValue*>::iterator NLVI =
NodeLVs.find(MI->second.getNode());
if (NLVI == NodeLVs.end()) continue;
// Iterate over all of the lattice values that have corresponding fields
// in the callee, merging in information as we go. Be careful about the
// fact that the callee may get passed the address of a substructure and
// other funny games.
//if (CalleeFacts.count(const_cast<DSNode*>(MI->first)) == 0) {
DSNode *CalleeNode = const_cast<DSNode*>(MI->first);
unsigned CalleeNodeOffset = MI->second.getOffset();
while (NLVI->first == MI->second.getNode()) {
// Figure out what offset in the callee this field would land.
unsigned FieldOff = NLVI->second->getFieldOffset()+CalleeNodeOffset;
// If the field is not within the callee node, ignore it.
if (FieldOff >= CalleeNode->getSize()) {
++NLVI;
continue;
}
// Okay, check to see if we have a lattice value for the field at offset
// FieldOff in the callee node.
const LatticeValue *CalleeLV = 0;
std::multimap<DSNode*, LatticeValue*>::iterator CFI =
CalleeFacts.lower_bound(CalleeNode);
for (; CFI != CalleeFacts.end() && CFI->first == CalleeNode; ++CFI)
if (CFI->second->getFieldOffset() == FieldOff) {
CalleeLV = CFI->second; // Found it!
break;
}
// If we don't, the lattice value hit bottom and we should remove the
// lattice value in the caller.
if (!CalleeLV) {
delete NLVI->second; // The lattice value hit bottom.
NodeLVs.erase(NLVI++);
continue;
}
// Finally, if we did find a corresponding entry, merge the information
// into the caller's lattice value and keep going.
if (NLVI->second->mergeInValue(CalleeLV)) {
// Okay, merging these two caused the caller value to hit bottom.
// Remove it.
delete NLVI->second; // The lattice value hit bottom.
NodeLVs.erase(NLVI++);
}
++NLVI; // We successfully merged in some information!
}
// If we ran out of facts to prove, just exit.
if (NodeLVs.empty()) return;
}
}
// The local analysis pass inconveniently discards many local function calls
// from the graph if they are to known functions. Loop over direct function
// calls not handled above and visit them as appropriate.
while (!IV.DirectCallSites.empty()) {
Instruction *Call = *IV.DirectCallSites.begin();
IV.DirectCallSites.erase(IV.DirectCallSites.begin());
// Is this one actually handled by DSA?
if (CalleesHandled.count(cast<Function>(Call->getOperand(0))))
continue;
// Collect the pointers involved in this call.
std::vector<Value*> Pointers;
if (isa<PointerType>(Call->getType()))
Pointers.push_back(Call);
for (unsigned i = 1, e = Call->getNumOperands(); i != e; ++i)
if (isa<PointerType>(Call->getOperand(i)->getType()))
Pointers.push_back(Call->getOperand(i));
// If this is an intrinsic function call, figure out which one.
unsigned IID = cast<Function>(Call->getOperand(0))->getIntrinsicID();
for (unsigned i = 0, e = Pointers.size(); i != e; ++i) {
// If any of our lattice values are passed into this call, which is
// specially handled by the local analyzer, inform the lattice function.
DSNode *N = DSG.getNodeForValue(Pointers[i]).getNode();
for (std::multimap<DSNode*, LatticeValue*>::iterator LVI =
NodeLVs.lower_bound(N); LVI != NodeLVs.end() && LVI->first == N;) {
bool AtBottom = false;
switch (IID) {
default:
AtBottom = LVI->second->visitRecognizedCall(*Call);
break;
case Intrinsic::memset:
if (Callbacks & Visit::Stores)
AtBottom = LVI->second->visitMemSet(*cast<CallInst>(Call));
break;
}
if (AtBottom) {
delete LVI->second;
NodeLVs.erase(LVI++);
} else {
++LVI;
}
}
}
}
}
/// ProcessNodesReachableFromGlobals - If we inferred anything about nodes
/// reachable from globals, we have to make sure that we incorporate data for
/// all graphs that include those globals due to the nature of the globals
/// graph.
///
void StructureFieldVisitorBase::
ProcessNodesReachableFromGlobals(DSGraph &DSG,
std::multimap<DSNode*,LatticeValue*> &NodeLVs){
// Start by marking all nodes reachable from globals.
DSScalarMap &SM = DSG.getScalarMap();
if (SM.global_begin() == SM.global_end()) return;
hash_set<const DSNode*> Reachable;
for (DSScalarMap::global_iterator GI = SM.global_begin(),
E = SM.global_end(); GI != E; ++GI)
SM[*GI].getNode()->markReachableNodes(Reachable);
if (Reachable.empty()) return;
// If any of the nodes with dataflow facts are reachable from the globals
// graph, we have to do the GG processing step.
bool MustProcessThroughGlobalsGraph = false;
for (std::multimap<DSNode*, LatticeValue*>::iterator I = NodeLVs.begin(),
E = NodeLVs.end(); I != E; ++I)
if (Reachable.count(I->first)) {
MustProcessThroughGlobalsGraph = true;
break;
}
if (!MustProcessThroughGlobalsGraph) return;
Reachable.clear();
// Compute the mapping from DSG to the globals graph.
DSGraph::NodeMapTy DSGToGGMap;
DSG.computeGToGGMapping(DSGToGGMap);
// Most of the times when we find facts about things reachable from globals we
// we are in the main graph. This means that we have *all* of the globals
// graph in this DSG. To be efficient, we compute the minimum set of globals
// that can reach any of the NodeLVs facts.
//
// I'm not aware of any wonderful way of computing the set of globals that
// points to the set of nodes in NodeLVs that is not N^2 in either NodeLVs or
// the number of globals, except to compute the inverse of DSG. As such, we
// compute the inverse graph of DSG, which basically has the edges going from
// pointed to nodes to pointing nodes. Because we only care about one
// connectedness properties, we ignore field info. In addition, we only
// compute inverse of the portion of the graph reachable from the globals.
std::set<std::pair<DSNode*,DSNode*> > InverseGraph;
for (DSScalarMap::global_iterator GI = SM.global_begin(),
E = SM.global_end(); GI != E; ++GI)
ComputeInverseGraphFrom(SM[*GI].getNode(), InverseGraph);
// Okay, now that we have our bastardized inverse graph, compute the set of
// globals nodes reachable from our lattice nodes.
for (std::multimap<DSNode*, LatticeValue*>::iterator I = NodeLVs.begin(),
E = NodeLVs.end(); I != E; ++I)
ComputeNodesReachableFrom(I->first, InverseGraph, Reachable);
// Now that we know which nodes point to the data flow facts, figure out which
// globals point to the data flow facts.
std::set<GlobalValue*> Globals;
for (hash_set<const DSNode*>::iterator I = Reachable.begin(),
E = Reachable.end(); I != E; ++I)
Globals.insert((*I)->globals_begin(), (*I)->globals_end());
// Finally, loop over all of the DSGraphs for the program, computing
// information for the graph if not done already, mapping the result into our
// context.
for (hash_map<const Function*, DSGraph*>::iterator GI = ECG.DSInfo.begin(),
E = ECG.DSInfo.end(); GI != E; ++GI) {
DSGraph &FG = *GI->second;
// Graphs can contain multiple functions, only process the graph once.
if (GI->first != FG.retnodes_begin()->first ||
// Also, do not bother reprocessing DSG.
&FG == &DSG)
continue;
bool GraphUsesGlobal = false;
for (std::set<GlobalValue*>::iterator I = Globals.begin(),
E = Globals.end(); I != E; ++I)
if (FG.getScalarMap().count(*I)) {
GraphUsesGlobal = true;
break;
}
// If this graph does not contain the global at all, there is no reason to
// even think about it.
if (!GraphUsesGlobal) continue;
// Otherwise, compute the full set of dataflow effects of the function.
std::multimap<DSNode*, LatticeValue*> &FGF = getCalleeFacts(FG);
//std::cerr << "Computed: " << FG.getFunctionNames() << "\n";
#if 0
for (std::multimap<DSNode*, LatticeValue*>::iterator I = FGF.begin(),
E = FGF.end(); I != E; ++I)
I->second->dump();
#endif
// Compute the mapping of nodes in the globals graph to the function's
// graph. Note that this function graph may not have nodes (or may have
// fragments of full nodes) in the globals graph, and we don't want this to
// pessimize the analysis.
std::multimap<const DSNode*, std::pair<DSNode*,int> > GraphMap;
DSGraph::NodeMapTy GraphToGGMap;
FG.computeGToGGMapping(GraphToGGMap);
// "Invert" the mapping. We compute the mapping from the start of a global
// graph node to a place in the graph's node. Note that not all of the GG
// node may be present in the graphs node, so there may be a negative offset
// involved.
while (!GraphToGGMap.empty()) {
DSNode *GN = const_cast<DSNode*>(GraphToGGMap.begin()->first);
DSNodeHandle &GGNH = GraphToGGMap.begin()->second;
GraphMap.insert(std::make_pair(GGNH.getNode(),
std::make_pair(GN, -GGNH.getOffset())));
GraphToGGMap.erase(GraphToGGMap.begin());
}
// Loop over all of the dataflow facts that we have computed, mapping them
// to the globals graph.
for (std::multimap<DSNode*, LatticeValue*>::iterator I = NodeLVs.begin(),
E = NodeLVs.end(); I != E; ) {
bool FactHitBottom = false;
//I->second->dump();
assert(I->first->getParentGraph() == &DSG);
assert(I->second->getNode()->getParentGraph() == &DSG);
// Node is in the GG?
DSGraph::NodeMapTy::iterator DSGToGGMapI = DSGToGGMap.find(I->first);
if (DSGToGGMapI != DSGToGGMap.end()) {
DSNodeHandle &GGNH = DSGToGGMapI->second;
const DSNode *GGNode = GGNH.getNode();
unsigned DSGToGGOffset = GGNH.getOffset();
// See if there is a node in FG that corresponds to this one. If not,
// no information will be computed in this scope, as the memory is not
// accessed.
std::multimap<const DSNode*, std::pair<DSNode*,int> >::iterator GMI =
GraphMap.find(GGNode);
// LatticeValOffset - The offset from the start of the GG Node to the
// start of the field we are interested in.
unsigned LatticeValOffset = I->second->getFieldOffset()+DSGToGGOffset;
// Loop over all of the nodes in FG that correspond to this single node
// in the GG.
for (; GMI != GraphMap.end() && GMI->first == GGNode; ++GMI) {
// Compute the offset to the field in the user graph.
unsigned FieldOffset = LatticeValOffset - GMI->second.second;
// If the field is within the amount of memory accessed by this scope,
// then there must be a corresponding lattice value.
DSNode *FGNode = GMI->second.first;
if (FieldOffset < FGNode->getSize()) {
LatticeValue *CorrespondingLV = 0;
std::multimap<DSNode*, LatticeValue*>::iterator FGFI =
FGF.find(FGNode);
for (; FGFI != FGF.end() && FGFI->first == FGNode; ++FGFI)
if (FGFI->second->getFieldOffset() == FieldOffset) {
CorrespondingLV = FGFI->second;
break;
}
// Finally, if either there was no corresponding fact (because it
// hit bottom in this scope), or if merging the two pieces of
// information makes it hit bottom, remember this.
if (CorrespondingLV == 0 ||
I->second->mergeInValue(CorrespondingLV))
FactHitBottom = true;
}
}
}
if (FactHitBottom) {
delete I->second;
NodeLVs.erase(I++);
if (NodeLVs.empty()) return;
} else {
++I;
}
}
}
}
