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Implement a "union-findy" version of DS-Analysis, which eliminates the

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Referrers list on DSNodes.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5536 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2003-02-11 23:11:51 +00:00
parent 2cec1d3867
commit 72d29a4b00
10 changed files with 388 additions and 362 deletions
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343
lib/Analysis/DataStructure/DataStructure.cpp
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@ -28,25 +28,41 @@ using namespace DS;
// DSNode Implementation
//===----------------------------------------------------------------------===//
DSNode::DSNode(enum NodeTy NT, const Type *T)
: Ty(Type::VoidTy), Size(0), NodeType(NT) {
DSNode::DSNode(unsigned NT, const Type *T, DSGraph *G)
: NumReferrers(0), Size(0), ParentGraph(G), Ty(Type::VoidTy), NodeType(NT) {
// Add the type entry if it is specified...
if (T) mergeTypeInfo(T, 0);
G->getNodes().push_back(this);
}
// DSNode copy constructor... do not copy over the referrers list!
DSNode::DSNode(const DSNode &N)
: Links(N.Links), Globals(N.Globals), Ty(N.Ty), Size(N.Size),
NodeType(N.NodeType) {
DSNode::DSNode(const DSNode &N, DSGraph *G)
: NumReferrers(0), Size(N.Size), ParentGraph(G), Ty(N.Ty),
Links(N.Links), Globals(N.Globals), NodeType(N.NodeType) {
G->getNodes().push_back(this);
}
void DSNode::removeReferrer(DSNodeHandle *H) {
// Search backwards, because we depopulate the list from the back for
// efficiency (because it's a vector).
std::vector<DSNodeHandle*>::reverse_iterator I =
std::find(Referrers.rbegin(), Referrers.rend(), H);
assert(I != Referrers.rend() && "Referrer not pointing to node!");
Referrers.erase(I.base()-1);
void DSNode::assertOK() const {
assert((Ty != Type::VoidTy ||
Ty == Type::VoidTy && (Size == 0 ||
(NodeType & DSNode::Array))) &&
"Node not OK!");
}
/// forwardNode - Mark this node as being obsolete, and all references to it
/// should be forwarded to the specified node and offset.
///
void DSNode::forwardNode(DSNode *To, unsigned Offset) {
assert(this != To && "Cannot forward a node to itself!");
assert(ForwardNH.isNull() && "Already forwarding from this node!");
if (To->Size <= 1) Offset = 0;
assert((Offset < To->Size || (Offset == To->Size && Offset == 0)) &&
"Forwarded offset is wrong!");
ForwardNH.setNode(To);
ForwardNH.setOffset(Offset);
NodeType = DEAD;
Size = 0;
Ty = Type::VoidTy;
}
// addGlobal - Add an entry for a global value to the Globals list. This also
@ -70,25 +86,32 @@ void DSNode::addGlobal(GlobalValue *GV) {
/// single byte with a single TypeEntry of "void".
///
void DSNode::foldNodeCompletely() {
if (isNodeCompletelyFolded()) return;
assert(!hasNoReferrers() &&
"Why would we collapse a node with no referrers?");
if (isNodeCompletelyFolded()) return; // If this node is already folded...
++NumFolds;
// We are no longer typed at all...
Ty = Type::VoidTy;
NodeType |= Array;
Size = 1;
// Create the node we are going to forward to...
DSNode *DestNode = new DSNode(NodeType|DSNode::Array, 0, ParentGraph);
DestNode->Ty = Type::VoidTy;
DestNode->Size = 1;
DestNode->Globals.swap(Globals);
// Loop over all of our referrers, making them point to our zero bytes of
// space.
for (std::vector<DSNodeHandle*>::iterator I = Referrers.begin(),
E = Referrers.end(); I != E; ++I)
(*I)->setOffset(0);
// Start forwarding to the destination node...
forwardNode(DestNode, 0);
if (Links.size()) {
DestNode->Links.push_back(Links[0]);
DSNodeHandle NH(DestNode);
// If we have links, merge all of our outgoing links together...
for (unsigned i = 1; i < Links.size(); ++i)
Links[0].mergeWith(Links[i]);
Links.resize(1);
// If we have links, merge all of our outgoing links together...
for (unsigned i = Links.size()-1; i != 0; --i)
NH.getNode()->Links[0].mergeWith(Links[i]);
Links.clear();
} else {
DestNode->Links.resize(1);
}
}
/// isNodeCompletelyFolded - Return true if this node has been completely
@ -401,9 +424,8 @@ void DSNode::MergeNodes(DSNodeHandle& CurNodeH, DSNodeHandle& NH) {
unsigned NSize = NH.getNode()->getSize();
// Merge the type entries of the two nodes together...
if (NH.getNode()->Ty != Type::VoidTy) {
if (NH.getNode()->Ty != Type::VoidTy)
CurNodeH.getNode()->mergeTypeInfo(NH.getNode()->Ty, NOffset);
}
assert((CurNodeH.getNode()->NodeType & DSNode::DEAD) == 0);
// If we are merging a node with a completely folded node, then both nodes are
@ -412,42 +434,34 @@ void DSNode::MergeNodes(DSNodeHandle& CurNodeH, DSNodeHandle& NH) {
if (CurNodeH.getNode()->isNodeCompletelyFolded()) {
if (!NH.getNode()->isNodeCompletelyFolded()) {
NH.getNode()->foldNodeCompletely();
assert(NH.getOffset()==0 && "folding did not make offset 0?");
assert(NH.getNode() && NH.getOffset() == 0 &&
"folding did not make offset 0?");
NOffset = NH.getOffset();
NSize = NH.getNode()->getSize();
assert(NOffset == 0 && NSize == 1);
}
} else if (NH.getNode()->isNodeCompletelyFolded()) {
CurNodeH.getNode()->foldNodeCompletely();
assert(CurNodeH.getOffset()==0 && "folding did not make offset 0?");
assert(CurNodeH.getNode() && CurNodeH.getOffset() == 0 &&
"folding did not make offset 0?");
NOffset = NH.getOffset();
NSize = NH.getNode()->getSize();
assert(NOffset == 0 && NSize == 1);
}
if (CurNodeH.getNode() == NH.getNode() || NH.getNode() == 0) return;
DSNode *N = NH.getNode();
if (CurNodeH.getNode() == N || N == 0) return;
assert((CurNodeH.getNode()->NodeType & DSNode::DEAD) == 0);
// Remove all edges pointing at N, causing them to point to 'this' instead.
// Make sure to adjust their offset, not just the node pointer.
// Also, be careful to use the DSNode* rather than NH since NH is one of
// the referrers and once NH refers to CurNodeH.getNode() this will
// become an infinite loop.
DSNode* N = NH.getNode();
unsigned OldNHOffset = NH.getOffset();
while (!N->Referrers.empty()) {
DSNodeHandle &Ref = *N->Referrers.back();
Ref = DSNodeHandle(CurNodeH.getNode(), NOffset+Ref.getOffset());
}
NH = DSNodeHandle(N, OldNHOffset); // reset NH to point back to where it was
// Start forwarding to the new node!
CurNodeH.getNode()->NodeType |= N->NodeType;
N->forwardNode(CurNodeH.getNode(), NOffset);
assert((CurNodeH.getNode()->NodeType & DSNode::DEAD) == 0);
// Make all of the outgoing links of *NH now be outgoing links of
// this. This can cause recursive merging!
//
for (unsigned i = 0; i < NH.getNode()->getSize(); i += DS::PointerSize) {
DSNodeHandle &Link = NH.getNode()->getLink(i);
// Make all of the outgoing links of N now be outgoing links of CurNodeH.
//
for (unsigned i = 0; i < N->getNumLinks(); ++i) {
DSNodeHandle &Link = N->getLink(i << DS::PointerShift);
if (Link.getNode()) {
// Compute the offset into the current node at which to
// merge this link. In the common case, this is a linear
@ -456,27 +470,22 @@ void DSNode::MergeNodes(DSNodeHandle& CurNodeH, DSNodeHandle& NH) {
// recursive merging, we must make sure to merge in all remaining
// links at offset zero.
unsigned MergeOffset = 0;
if (CurNodeH.getNode()->Size != 1)
MergeOffset = (i+NOffset) % CurNodeH.getNode()->getSize();
CurNodeH.getNode()->addEdgeTo(MergeOffset, Link);
DSNode *CN = CurNodeH.getNode();
if (CN->Size != 1)
MergeOffset = ((i << DS::PointerShift)+NOffset) % CN->getSize();
CN->addEdgeTo(MergeOffset, Link);
}
}
// Now that there are no outgoing edges, all of the Links are dead.
NH.getNode()->Links.clear();
NH.getNode()->Size = 0;
NH.getNode()->Ty = Type::VoidTy;
// Merge the node types
CurNodeH.getNode()->NodeType |= NH.getNode()->NodeType;
NH.getNode()->NodeType = DEAD; // NH is now a dead node.
N->Links.clear();
// Merge the globals list...
if (!NH.getNode()->Globals.empty()) {
MergeSortedVectors(CurNodeH.getNode()->Globals, NH.getNode()->Globals);
if (!N->Globals.empty()) {
MergeSortedVectors(CurNodeH.getNode()->Globals, N->Globals);
// Delete the globals from the old node...
NH.getNode()->Globals.clear();
std::vector<GlobalValue*>().swap(N->Globals);
}
}
@ -606,9 +615,8 @@ DSNodeHandle DSGraph::cloneInto(const DSGraph &G,
clearBits |= DSNode::DEAD; // Clear dead flag...
for (unsigned i = 0, e = G.Nodes.size(); i != e; ++i) {
DSNode *Old = G.Nodes[i];
DSNode *New = new DSNode(*Old);
DSNode *New = new DSNode(*Old, this);
New->NodeType &= ~clearBits;
Nodes.push_back(New);
OldNodeMap[Old] = New;
}
@ -625,8 +633,8 @@ DSNodeHandle DSGraph::cloneInto(const DSGraph &G,
E = G.ScalarMap.end(); I != E; ++I) {
DSNodeHandle &H = OldValMap[I->first];
DSNodeHandle &MappedNode = OldNodeMap[I->second.getNode()];
H.setNode(MappedNode.getNode());
H.setOffset(I->second.getOffset()+MappedNode.getOffset());
H.setNode(MappedNode.getNode());
if (isa<GlobalValue>(I->first)) { // Is this a global?
hash_map<Value*, DSNodeHandle>::iterator GVI = ScalarMap.find(I->first);
@ -705,6 +713,7 @@ void DSGraph::mergeInGraph(DSCallSite &CS, const DSGraph &Graph,
if (AI == F.aend()) break;
// Add the link from the argument scalar to the provided value
assert(ScalarMap->count(AI) && "Argument not in scalar map?");
DSNodeHandle &NH = (*ScalarMap)[AI];
assert(NH.getNode() && "Pointer argument without scalarmap entry?");
NH.mergeWith(CS.getPtrArg(i));
@ -775,7 +784,7 @@ void DSGraph::markIncompleteNodes(unsigned Flags) {
static inline void killIfUselessEdge(DSNodeHandle &Edge) {
if (DSNode *N = Edge.getNode()) // Is there an edge?
if (N->getReferrers().size() == 1) // Does it point to a lonely node?
if (N->getNumReferrers() == 1) // Does it point to a lonely node?
if ((N->NodeType & ~DSNode::Incomplete) == 0 && // No interesting info?
N->getType() == Type::VoidTy && !N->isNodeCompletelyFolded())
Edge.setNode(0); // Kill the edge!
@ -805,7 +814,7 @@ static void removeIdenticalCalls(std::vector<DSCallSite> &Calls,
// If the Callee is a useless edge, this must be an unreachable call site,
// eliminate it.
if (CS.isIndirectCall() && CS.getCalleeNode()->getReferrers().size() == 1 &&
if (CS.isIndirectCall() && CS.getCalleeNode()->getNumReferrers() == 1 &&
CS.getCalleeNode()->NodeType == 0) { // No useful info?
std::cerr << "WARNING: Useless call site found??\n";
CS.swap(Calls.back());
@ -893,13 +902,26 @@ void DSGraph::removeTriviallyDeadNodes() {
// have all of these properties and still have incoming edges, due to the
// scalar map, so we check those now.
//
if (Node->getReferrers().size() == Node->getGlobals().size()) {
if (Node->getNumReferrers() == Node->getGlobals().size()) {
std::vector<GlobalValue*> &Globals = Node->getGlobals();
for (unsigned j = 0, e = Globals.size(); j != e; ++j)
ScalarMap.erase(Globals[j]);
Globals.clear();
// Loop through and make sure all of the globals are referring directly
// to the node...
for (unsigned j = 0, e = Globals.size(); j != e; ++j) {
DSNode *N = ScalarMap.find(Globals[j])->second.getNode();
assert(N == Node && "ScalarMap doesn't match globals list!");
}
// Make sure numreferrers still agrees, if so, the node is truely dead.
if (Node->getNumReferrers() == Globals.size()) {
for (unsigned j = 0, e = Globals.size(); j != e; ++j)
ScalarMap.erase(Globals[j]);
Globals.clear();
assert(Node->hasNoReferrers() && "Shouldn't have refs now!");
Node->NodeType = DSNode::DEAD;
Node->NodeType = DSNode::DEAD;
}
}
}
@ -919,6 +941,7 @@ void DSGraph::removeTriviallyDeadNodes() {
///
void DSNode::markReachableNodes(hash_set<DSNode*> &ReachableNodes) {
if (this == 0) return;
assert(getForwardNode() == 0 && "Cannot mark a forwarded node!");
if (ReachableNodes.count(this)) return; // Already marked reachable
ReachableNodes.insert(this); // Is reachable now
@ -942,6 +965,7 @@ void DSCallSite::markReachableNodes(hash_set<DSNode*> &Nodes) {
static bool CanReachAliveNodes(DSNode *N, hash_set<DSNode*> &Alive,
hash_set<DSNode*> &Visited) {
if (N == 0) return false;
assert(N->getForwardNode() == 0 && "Cannot mark a forwarded node!");
// If we know that this node is alive, return so!
if (Alive.count(N)) return true;
@ -1015,7 +1039,7 @@ void DSGraph::removeDeadNodes(unsigned Flags) {
do {
Visited.clear();
// If any global nodes points to a non-global that is "alive", the global is
// "alive" as well... Remov it from the GlobalNodes list so we only have
// "alive" as well... Remove it from the GlobalNodes list so we only have
// unreachable globals in the list.
//
Iterate = false;
@ -1055,22 +1079,28 @@ void DSGraph::removeDeadNodes(unsigned Flags) {
// should be moved to the globals graph. Loop over all nodes, eliminating
// completely unreachable nodes, and moving visited nodes to the globals graph
//
std::vector<DSNode*> DeadNodes;
DeadNodes.reserve(Nodes.size());
for (unsigned i = 0; i != Nodes.size(); ++i)
if (!Alive.count(Nodes[i])) {
DSNode *N = Nodes[i];
std::swap(Nodes[i--], Nodes.back()); // move node to end of vector
Nodes.pop_back(); // Erase node from alive list.
Nodes[i--] = Nodes.back(); // move node to end of vector
Nodes.pop_back(); // Erase node from alive list.
if (!(Flags & DSGraph::RemoveUnreachableGlobals) && // Not in TD pass
Visited.count(N)) { // Visited but not alive?
GlobalsGraph->Nodes.push_back(N); // Move node to globals graph
N->setParentGraph(GlobalsGraph);
} else { // Otherwise, delete the node
assert(((N->NodeType & DSNode::GlobalNode) == 0 ||
(Flags & DSGraph::RemoveUnreachableGlobals))
&& "Killing a global?");
while (!N->hasNoReferrers()) // Rewrite referrers
N->getReferrers().back()->setNode(0);
delete N; // Usecount is zero
//std::cerr << "[" << i+1 << "/" << DeadNodes.size()
// << "] Node is dead: "; N->dump();
DeadNodes.push_back(N);
N->dropAllReferences();
}
} else {
assert(Nodes[i]->getForwardNode() == 0 && "Alive forwarded node?");
}
// Now that the nodes have either been deleted or moved to the globals graph,
@ -1096,7 +1126,8 @@ void DSGraph::removeDeadNodes(unsigned Flags) {
// Merging leaves behind silly nodes, we remove them to avoid polluting the
// globals graph.
GlobalsGraph->removeTriviallyDeadNodes();
if (!GlobalNodes.empty())
GlobalsGraph->removeTriviallyDeadNodes();
} else {
// If we are in the top-down pass, remove all unreachable globals from the
// ScalarMap...
@ -1104,10 +1135,18 @@ void DSGraph::removeDeadNodes(unsigned Flags) {
ScalarMap.erase(GlobalNodes[i].first);
}
// Loop over all of the dead nodes now, deleting them since their referrer
// count is zero.
for (unsigned i = 0, e = DeadNodes.size(); i != e; ++i)
delete DeadNodes[i];
DEBUG(AssertGraphOK(); GlobalsGraph->AssertGraphOK());
}
void DSGraph::AssertGraphOK() const {
for (unsigned i = 0, e = Nodes.size(); i != e; ++i)
Nodes[i]->assertOK();
return; // FIXME: remove
for (hash_map<Value*, DSNodeHandle>::const_iterator I = ScalarMap.begin(),
E = ScalarMap.end(); I != E; ++I) {
assert(I->second.getNode() && "Null node in scalarmap!");
@ -1121,149 +1160,3 @@ void DSGraph::AssertGraphOK() const {
AssertCallNodesInGraph();
AssertAuxCallNodesInGraph();
}
#if 0
//===----------------------------------------------------------------------===//
// GlobalDSGraph Implementation
//===----------------------------------------------------------------------===//
#if 0
// Bits used in the next function
static const char ExternalTypeBits = DSNode::GlobalNode | DSNode::HeapNode;
// cloneGlobalInto - Clone the given global node and all its target links
// (and all their llinks, recursively).
//
DSNode *DSGraph::cloneGlobalInto(const DSNode *GNode) {
if (GNode == 0 || GNode->getGlobals().size() == 0) return 0;
// If a clone has already been created for GNode, return it.
DSNodeHandle& ValMapEntry = ScalarMap[GNode->getGlobals()[0]];
if (ValMapEntry != 0)
return ValMapEntry;
// Clone the node and update the ValMap.
DSNode* NewNode = new DSNode(*GNode);
ValMapEntry = NewNode; // j=0 case of loop below!
Nodes.push_back(NewNode);
for (unsigned j = 1, N = NewNode->getGlobals().size(); j < N; ++j)
ScalarMap[NewNode->getGlobals()[j]] = NewNode;
// Rewrite the links in the new node to point into the current graph.
for (unsigned j = 0, e = GNode->getNumLinks(); j != e; ++j)
NewNode->setLink(j, cloneGlobalInto(GNode->getLink(j)));
return NewNode;
}
// GlobalDSGraph::cloneNodeInto - Clone a global node and all its externally
// visible target links (and recursively their such links) into this graph.
// NodeCache maps the node being cloned to its clone in the Globals graph,
// in order to track cycles.
// GlobalsAreFinal is a flag that says whether it is safe to assume that
// an existing global node is complete. This is important to avoid
// reinserting all globals when inserting Calls to functions.
// This is a helper function for cloneGlobals and cloneCalls.
//
DSNode* GlobalDSGraph::cloneNodeInto(DSNode *OldNode,
hash_map<const DSNode*, DSNode*> &NodeCache,
bool GlobalsAreFinal) {
if (OldNode == 0) return 0;
// The caller should check this is an external node. Just more efficient...
assert((OldNode->NodeType & ExternalTypeBits) && "Non-external node");
// If a clone has already been created for OldNode, return it.
DSNode*& CacheEntry = NodeCache[OldNode];
if (CacheEntry != 0)
return CacheEntry;
// The result value...
DSNode* NewNode = 0;
// If nodes already exist for any of the globals of OldNode,
// merge all such nodes together since they are merged in OldNode.
// If ValueCacheIsFinal==true, look for an existing node that has
// an identical list of globals and return it if it exists.
//
for (unsigned j = 0, N = OldNode->getGlobals().size(); j != N; ++j)
if (DSNode *PrevNode = ScalarMap[OldNode->getGlobals()[j]].getNode()) {
if (NewNode == 0) {
NewNode = PrevNode; // first existing node found
if (GlobalsAreFinal && j == 0)
if (OldNode->getGlobals() == PrevNode->getGlobals()) {
CacheEntry = NewNode;
return NewNode;
}
}
else if (NewNode != PrevNode) { // found another, different from prev
// update ValMap *before* merging PrevNode into NewNode
for (unsigned k = 0, NK = PrevNode->getGlobals().size(); k < NK; ++k)
ScalarMap[PrevNode->getGlobals()[k]] = NewNode;
NewNode->mergeWith(PrevNode);
}
} else if (NewNode != 0) {
ScalarMap[OldNode->getGlobals()[j]] = NewNode; // add the merged node
}
// If no existing node was found, clone the node and update the ValMap.
if (NewNode == 0) {
NewNode = new DSNode(*OldNode);
Nodes.push_back(NewNode);
for (unsigned j = 0, e = NewNode->getNumLinks(); j != e; ++j)
NewNode->setLink(j, 0);
for (unsigned j = 0, N = NewNode->getGlobals().size(); j < N; ++j)
ScalarMap[NewNode->getGlobals()[j]] = NewNode;
}
else
NewNode->NodeType |= OldNode->NodeType; // Markers may be different!
// Add the entry to NodeCache
CacheEntry = NewNode;
// Rewrite the links in the new node to point into the current graph,
// but only for links to external nodes. Set other links to NULL.
for (unsigned j = 0, e = OldNode->getNumLinks(); j != e; ++j) {
DSNode* OldTarget = OldNode->getLink(j);
if (OldTarget && (OldTarget->NodeType & ExternalTypeBits)) {
DSNode* NewLink = this->cloneNodeInto(OldTarget, NodeCache);
if (NewNode->getLink(j))
NewNode->getLink(j)->mergeWith(NewLink);
else
NewNode->setLink(j, NewLink);
}
}
// Remove all local markers
NewNode->NodeType &= ~(DSNode::AllocaNode | DSNode::ScalarNode);
return NewNode;
}
// GlobalDSGraph::cloneCalls - Clone function calls and their visible target
// links (and recursively their such links) into this graph.
//
void GlobalDSGraph::cloneCalls(DSGraph& Graph) {
hash_map<const DSNode*, DSNode*> NodeCache;
std::vector<DSCallSite >& FromCalls =Graph.FunctionCalls;
FunctionCalls.reserve(FunctionCalls.size() + FromCalls.size());
for (int i = 0, ei = FromCalls.size(); i < ei; ++i) {
DSCallSite& callCopy = FunctionCalls.back();
callCopy.reserve(FromCalls[i].size());
for (unsigned j = 0, ej = FromCalls[i].size(); j != ej; ++j)
callCopy.push_back
((FromCalls[i][j] && (FromCalls[i][j]->NodeType & ExternalTypeBits))
? cloneNodeInto(FromCalls[i][j], NodeCache, true)
: 0);
}
// remove trivially identical function calls
removeIdenticalCalls(FunctionCalls, "Globals Graph");
}
#endif
#endif