//
// Method: findGlobalPoolNodes()
//
// Description:
// This method finds DSNodes that are reachable from globals and that need a
// pool. The Automatic Pool Allocation transform will use the returned
// information to build global pools for the DSNodes in question.
//
// Note that this method does not assign DSNodes to pools; it merely decides
// which DSNodes are reachable from globals and will need a pool of global
// scope.
//
// Outputs:
// Nodes - The DSNodes that are both reachable from globals and which should
// have global pools will be *added* to this container.
//
void
AllHeapNodesHeuristic::findGlobalPoolNodes (DSNodeSet_t & Nodes) {
// Get the globals graph for the program.
DSGraph* GG = Graphs->getGlobalsGraph();
// Get all of the nodes reachable from globals.
DenseSet<const DSNode*> GlobalHeapNodes;
GetNodesReachableFromGlobals (GG, GlobalHeapNodes);
//
// Create a global pool for each global DSNode.
//
for (DenseSet<const DSNode *>::iterator NI = GlobalHeapNodes.begin();
NI != GlobalHeapNodes.end();++NI) {
const DSNode * N = *NI;
PoolMap[N] = OnePool(N);
}
//
// Now find all DSNodes belonging to function-local DSGraphs which are
// mirrored in the globals graph. These DSNodes require a global pool, too.
//
for (Module::iterator F = M->begin(); F != M->end(); ++F) {
if (Graphs->hasDSGraph(*F)) {
DSGraph* G = Graphs->getDSGraph(*F);
DSGraph::NodeMapTy NodeMap;
G->computeGToGGMapping (NodeMap);
//
// Scan through all DSNodes in the local graph. If a local DSNode has a
// corresponding DSNode in the globals graph that is reachable from a
// global, then add the local DSNode to the set of DSNodes reachable from
// a global.
//
DSGraph::node_iterator ni = G->node_begin();
for (; ni != G->node_end(); ++ni) {
DSNode * N = ni;
DSNode * GGN = NodeMap[N].getNode();
//assert (!GGN || GlobalHeapNodes.count (GGN));
if (GGN && GlobalHeapNodes.count (GGN))
PoolMap[GGN].NodesInPool.push_back (N);
}
}
}
//
// Copy the values into the output container. Note that DenseSet has no
// iterator traits (or whatever allows us to treat DenseSet has a generic
// container), so we have to use a loop to copy values from the DenseSet into
// the output container.
//
for (DenseSet<const DSNode*>::iterator I = GlobalHeapNodes.begin(),
E = GlobalHeapNodes.end(); I != E; ++I) {
Nodes.insert (*I);
}
return;
}
//
// Method: getLocalPoolNodes()
//
// Description:
// For a given function, determine which DSNodes for that function should have
// local pools created for them.
//
void
Heuristic::getLocalPoolNodes (const Function & F, DSNodeList_t & Nodes) {
//
// Get the DSGraph of the specified function. If the DSGraph has no nodes,
// then there is nothing we need to do.
//
DSGraph* G = Graphs->getDSGraph(F);
if (G->node_begin() == G->node_end()) return;
//
// 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.
Graphs->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. In other words, scan over the DSGraph and
// find nodes for which a new pool must be created within this function.
//
for (DSGraph::node_iterator I = G->node_begin(), E = G->node_end();
I != E;
++I){
// Get the DSNode and, if applicable, its mirror in the globals graph
DSNode * N = I;
DSNode * GGN = GlobalsGraphNodeMapping[N].getNode();
//
// Only the following nodes are pool allocated:
// 1) Local Heap nodes
// 2) Nodes which are mirrored in the globals graph and, in the globals
// graph, are heap nodes.
//
if ((N->isHeapNode()) || (GGN && GGN->isHeapNode())) {
if (!(GlobalPoolNodes.count (N) || GlobalPoolNodes.count (GGN))) {
// Otherwise, if it was not passed in from outside the function, it must
// be a local pool!
assert((!N->isGlobalNode() || N->isPtrToIntNode()) && "Should be in global mapping!");
if(!N->isPtrToIntNode()) {
Nodes.push_back (N);
}
}
}
}
return;
}
// Get all nodes in all function DSGraphs and the global DSGraph that contain
// global values.
void CSDataRando::findGlobalNodes(Module &M) {
DSGraph *GG = DSA->getGlobalsGraph();
for (auto i = GG->node_begin(), e = GG->node_end(); i != e; i++) {
GlobalNodes.insert(&*i);
}
for (Function &F : M) {
if ((!F.isDeclaration()) && DSA->hasDSGraph(F)) {
DSGraph *G = DSA->getDSGraph(F);
FuncInfo &FI = FunctionInfo[&F];
DSGraph::NodeMapTy NodeMap;
G->computeGToGGMapping(NodeMap);
for (auto i : NodeMap) {
GlobalNodes.insert(i.first);
FI.ToGlobalNodeMap[i.first] = i.second.getNode();
}
}
}
}
//
// Method: findGlobalPoolNodes()
//
// Description:
// This method finds DSNodes that are reachable from globals and that need a
// pool. The Automatic Pool Allocation transform will use the returned
// information to build global pools for the DSNodes in question.
//
// For efficiency, this method also determines which DSNodes should be in the
// same pool.
//
// Outputs:
// Nodes - The DSNodes that are both reachable from globals and which should
// have global pools will be *added* to this container.
//
void
AllNodesHeuristic::findGlobalPoolNodes (DSNodeSet_t & Nodes) {
// Get the globals graph for the program.
DSGraph* GG = Graphs->getGlobalsGraph();
//
// Get all of the nodes reachable from globals.
//
DenseSet<const DSNode*> GlobalNodes;
GetNodesReachableFromGlobals (GG, GlobalNodes);
//
// Create a global pool for each global DSNode.
//
for (DenseSet<const DSNode *>::iterator NI = GlobalNodes.begin();
NI != GlobalNodes.end();
++NI) {
const DSNode * N = *NI;
PoolMap[N] = OnePool(N);
}
//
// Now find all DSNodes belonging to function-local DSGraphs which are
// mirrored in the globals graph. These DSNodes require a global pool, too,
// but must use the same pool as the one assigned to the corresponding global
// DSNode.
//
for (Module::iterator F = M->begin(); F != M->end(); ++F) {
//
// Ignore functions that have no DSGraph.
//
if (!(Graphs->hasDSGraph(*F))) continue;
//
// Compute a mapping between local DSNodes and DSNodes in the globals
// graph.
//
DSGraph* G = Graphs->getDSGraph(*F);
DSGraph::NodeMapTy NodeMap;
G->computeGToGGMapping (NodeMap);
//
// Scan through all DSNodes in the local graph. If a local DSNode has a
// corresponding DSNode in the globals graph that is reachable from a
// global, then add the local DSNode to the set of DSNodes reachable from
// a global.
//
DSGraph::node_iterator ni = G->node_begin();
for (; ni != G->node_end(); ++ni) {
DSNode * N = ni;
DSNode * GGN = NodeMap[N].getNode();
assert (!GGN || GlobalNodes.count (GGN));
if (GGN && GlobalNodes.count (GGN))
PoolMap[GGN].NodesInPool.push_back (N);
}
}
//
// Scan through all the local graphs looking for DSNodes which may be
// reachable by a global. These nodes may not end up in the globals graph
// because of the fact that DSA doesn't actually know what is happening to
// them.
//
// FIXME: I believe this code causes a condition in which a local DSNode is
// given a local pool in one function but not in other functions.
// Someone needs to investigate whether DSA is being consistent here,
// and if not, if that inconsistency is correct.
//
#if 0
for (Module::iterator F = M->begin(); F != M->end(); ++F) {
if (F->isDeclaration()) continue;
DSGraph* G = Graphs->getDSGraph(*F);
for (DSGraph::node_iterator I = G->node_begin(), E = G->node_end();
I != E;
++I) {
DSNode * Node = I;
if (Node->isExternalNode() || Node->isUnknownNode()) {
GlobalNodes.insert (Node);
}
}
}
#endif
//
// Copy the values into the output container. Note that DenseSet has no
// iterator traits (or whatever allows us to treat DenseSet has a generic
// container), so we have to use a loop to copy values from the DenseSet into
// the output container.
//
// Note that we do not copy local DSNodes into the output container; we
// merely copy those nodes in the globals graph.
//
for (DenseSet<const DSNode*>::iterator I = GlobalNodes.begin(),
E = GlobalNodes.end(); I != E; ++I) {
Nodes.insert (*I);
}
return;
}
/// 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;
}
}
}
}
