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Implement the globals graph! 

llvm-svn: 5477
This commit is contained in:
Chris Lattner 2003-02-03 19:12:15 +00:00
parent e396e9bbae
commit 8bb9513bd8
1 changed files with 165 additions and 130 deletions
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279
llvm/lib/Analysis/DataStructure/DataStructure.cpp
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@ -233,7 +233,8 @@ bool DSNode::mergeTypeInfo(const Type *NewTy, unsigned Offset) {
break;
}
default:
assert(0 && "Unknown type!");
foldNodeCompletely();
return true;
}
}
@ -616,15 +617,12 @@ DSNodeHandle DSGraph::cloneInto(const DSGraph &G,
// Remove alloca markers as specified
if (CloneFlags & (StripAllocaBit | StripModRefBits)) {
unsigned short clearBits = (CloneFlags & StripAllocaBit
? DSNode::AllocaNode : 0)
| (CloneFlags & StripModRefBits
? (DSNode::Modified | DSNode::Read) : 0);
for (unsigned i = FN, e = Nodes.size(); i != e; ++i)
Nodes[i]->NodeType &= ~clearBits;
unsigned clearBits = (CloneFlags & StripAllocaBit ? DSNode::AllocaNode : 0)
| (CloneFlags & StripModRefBits ? (DSNode::Modified | DSNode::Read) : 0);
maskNodeTypes(~clearBits);
}
// Copy the value map... and merge all of the global nodes...
// Copy the scalar map... merging all of the global nodes...
for (hash_map<Value*, DSNodeHandle>::const_iterator I = G.ScalarMap.begin(),
E = G.ScalarMap.end(); I != E; ++I) {
DSNodeHandle &H = OldValMap[I->first];
@ -634,13 +632,12 @@ DSNodeHandle DSGraph::cloneInto(const DSGraph &G,
if (isa<GlobalValue>(I->first)) { // Is this a global?
hash_map<Value*, DSNodeHandle>::iterator GVI = ScalarMap.find(I->first);
if (GVI != ScalarMap.end()) { // Is the global value in this fn already?
if (GVI != ScalarMap.end()) // Is the global value in this fn already?
GVI->second.mergeWith(H);
} else {
else
ScalarMap[I->first] = H; // Add global pointer to this graph
}
}
}
if (!(CloneFlags & DontCloneCallNodes)) {
// Copy the function calls list...
@ -716,33 +713,6 @@ void DSGraph::mergeInGraph(DSCallSite &CS, const DSGraph &Graph,
}
}
#if 0
// 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;
}
#endif
// markIncompleteNodes - Mark the specified node as having contents that are not
// known with the current analysis we have performed. Because a node makes all
@ -808,27 +778,6 @@ void DSGraph::markIncompleteNodes(unsigned Flags) {
}
}
// removeRefsToGlobal - Helper function that removes globals from the
// ScalarMap so that the referrer count will go down to zero.
static void removeRefsToGlobal(DSNode* N,
hash_map<Value*, DSNodeHandle> &ScalarMap) {
while (!N->getGlobals().empty()) {
GlobalValue *GV = N->getGlobals().back();
N->getGlobals().pop_back();
ScalarMap.erase(GV);
}
}
// isNodeDead - This method checks to see if a node is dead, and if it isn't, it
// checks to see if there are simple transformations that it can do to make it
// dead.
//
bool DSGraph::isNodeDead(DSNode *N) {
// Is it a trivially dead shadow node?
return N->getReferrers().empty() && (N->NodeType & ~DSNode::DEAD) == 0;
}
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?
@ -927,12 +876,33 @@ void DSGraph::removeTriviallyDeadNodes() {
removeIdenticalCalls(FunctionCalls, Func ? Func->getName() : "");
removeIdenticalCalls(AuxFunctionCalls, Func ? Func->getName() : "");
for (unsigned i = 0; i != Nodes.size(); ++i)
if (isNodeDead(Nodes[i])) { // This node is dead!
delete Nodes[i]; // Free memory...
for (unsigned i = 0; i != Nodes.size(); ++i) {
DSNode *Node = Nodes[i];
if (!(Node->NodeType & ~(DSNode::Composition | DSNode::Array |
DSNode::DEAD))) {
// This is a useless node if it has no mod/ref info (checked above),
// outgoing edges (which it cannot, as it is not modified in this
// context), and it has no incoming edges. If it is a global node it may
// 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()) {
std::vector<GlobalValue*> &Globals = Node->getGlobals();
for (unsigned j = 0, e = Globals.size(); j != e; ++j)
ScalarMap.erase(Globals[j]);
Globals.clear();
Node->NodeType = DSNode::DEAD;
}
}
if ((Node->NodeType & ~DSNode::DEAD) == 0 &&
Node->getReferrers().empty()) { // This node is dead!
delete Node; // Free memory...
Nodes.erase(Nodes.begin()+i--); // Remove from node list...
}
}
}
/// markReachableNodes - This method recursively traverses the specified
@ -952,8 +922,8 @@ void DSCallSite::markReachableNodes(hash_set<DSNode*> &Nodes) {
getRetVal().getNode()->markReachableNodes(Nodes);
getCallee().getNode()->markReachableNodes(Nodes);
for (unsigned j = 0, e = getNumPtrArgs(); j != e; ++j)
getPtrArg(j).getNode()->markReachableNodes(Nodes);
for (unsigned i = 0, e = getNumPtrArgs(); i != e; ++i)
getPtrArg(i).getNode()->markReachableNodes(Nodes);
}
// CanReachAliveNodes - Simple graph walker that recursively traverses the graph
@ -989,30 +959,12 @@ static bool CallSiteUsesAliveArgs(DSCallSite &CS, hash_set<DSNode*> &Alive,
if (CanReachAliveNodes(CS.getRetVal().getNode(), Alive, Visited) ||
CanReachAliveNodes(CS.getCallee().getNode(), Alive, Visited))
return true;
for (unsigned j = 0, e = CS.getNumPtrArgs(); j != e; ++j)
if (CanReachAliveNodes(CS.getPtrArg(j).getNode(), Alive, Visited))
for (unsigned i = 0, e = CS.getNumPtrArgs(); i != e; ++i)
if (CanReachAliveNodes(CS.getPtrArg(i).getNode(), Alive, Visited))
return true;
return false;
}
// GlobalIsAlivenessRoot - Return true if the specified global node is
// intrinsically alive in the context of the current graph (ie, it is a root of
// aliveness). For TD graphs, no globals are. For the BU graphs all are unless
// they are trivial globals...
//
static bool GlobalIsAlivenessRoot(DSNode *N, unsigned Flags) {
if (Flags & DSGraph::RemoveUnreachableGlobals)
return false; // If we are to remove all globals, go for it.
// Ok, we are keeping globals... hrm, we can still delete it if it has no
// links, and no mod/ref or other info... If it is not modified, it can't
// have links...
//
if ((N->NodeType & ~(DSNode::Composition | DSNode::Array)) == 0)
return false;
return true;
}
// removeDeadNodes - Use a more powerful reachability analysis to eliminate
// subgraphs that are unreachable. This often occurs because the data
// structure doesn't "escape" into it's caller, and thus should be eliminated
@ -1020,7 +972,8 @@ static bool GlobalIsAlivenessRoot(DSNode *N, unsigned Flags) {
// inlining graphs.
//
void DSGraph::removeDeadNodes(unsigned Flags) {
// Reduce the amount of work we have to do...
// Reduce the amount of work we have to do... remove dummy nodes left over by
// merging...
removeTriviallyDeadNodes();
// FIXME: Merge nontrivially identical call nodes...
@ -1032,75 +985,133 @@ void DSGraph::removeDeadNodes(unsigned Flags) {
// Mark all nodes reachable by (non-global) scalar nodes as alive...
for (hash_map<Value*, DSNodeHandle>::iterator I = ScalarMap.begin(),
E = ScalarMap.end(); I != E; ++I)
if (!isa<GlobalValue>(I->first) ||
GlobalIsAlivenessRoot(I->second.getNode(), Flags))
if (!isa<GlobalValue>(I->first))
I->second.getNode()->markReachableNodes(Alive);
else // Keep track of global nodes
else { // Keep track of global nodes
GlobalNodes.push_back(std::make_pair(I->first, I->second.getNode()));
assert(I->second.getNode() && "Null global node?");
}
// The return value is alive as well...
RetNode.getNode()->markReachableNodes(Alive);
// If any global nodes points to a non-global that is "alive", the global is
// "alive" as well...
//
hash_set<DSNode*> Visited;
for (unsigned i = 0, e = GlobalNodes.size(); i != e; ++i)
CanReachAliveNodes(GlobalNodes[i].second, Alive, Visited);
std::vector<bool> FCallsAlive(FunctionCalls.size());
// Mark any nodes reachable by primary calls as alive...
for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i)
if (!(Flags & DSGraph::RemoveUnreachableGlobals) ||
CallSiteUsesAliveArgs(FunctionCalls[i], Alive, Visited)) {
FunctionCalls[i].markReachableNodes(Alive);
FCallsAlive[i] = true;
bool Iterate;
hash_set<DSNode*> Visited;
std::vector<unsigned char> AuxFCallsAlive(AuxFunctionCalls.size());
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
// unreachable globals in the list.
//
Iterate = false;
for (unsigned i = 0; i != GlobalNodes.size(); ++i)
if (CanReachAliveNodes(GlobalNodes[i].second, Alive, Visited)) {
std::swap(GlobalNodes[i--], GlobalNodes.back()); // Move to end to erase
GlobalNodes.pop_back(); // Erase efficiently
Iterate = true;
}
std::vector<bool> AuxFCallsAlive(AuxFunctionCalls.size());
for (unsigned i = 0, e = AuxFunctionCalls.size(); i != e; ++i)
if (!(Flags & DSGraph::RemoveUnreachableGlobals) ||
if (!AuxFCallsAlive[i] &&
CallSiteUsesAliveArgs(AuxFunctionCalls[i], Alive, Visited)) {
AuxFunctionCalls[i].markReachableNodes(Alive);
AuxFCallsAlive[i] = true;
Iterate = true;
}
// Remove all dead function calls...
unsigned CurIdx = 0;
for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i)
if (FCallsAlive[i])
FunctionCalls[CurIdx++].swap(FunctionCalls[i]);
// Crop all the bad ones out...
FunctionCalls.erase(FunctionCalls.begin()+CurIdx, FunctionCalls.end());
} while (Iterate);
// Remove all dead aux function calls...
CurIdx = 0;
unsigned CurIdx = 0;
for (unsigned i = 0, e = AuxFunctionCalls.size(); i != e; ++i)
if (AuxFCallsAlive[i])
AuxFunctionCalls[CurIdx++].swap(AuxFunctionCalls[i]);
// Crop all the bad ones out...
if (!(Flags & DSGraph::RemoveUnreachableGlobals)) {
// Move the unreachable call nodes to the globals graph...
GlobalsGraph->AuxFunctionCalls.insert(GlobalsGraph->AuxFunctionCalls.end(),
AuxFunctionCalls.begin()+CurIdx,
AuxFunctionCalls.end());
}
// Crop all the useless ones out...
AuxFunctionCalls.erase(AuxFunctionCalls.begin()+CurIdx,
AuxFunctionCalls.end());
// Remove all unreachable globals from the ScalarMap
for (unsigned i = 0, e = GlobalNodes.size(); i != e; ++i)
if (!Alive.count(GlobalNodes[i].second))
ScalarMap.erase(GlobalNodes[i].first);
// Loop over all unreachable nodes, dropping their references...
// At this point, any nodes which are visited, but not alive, are nodes which
// should be moved to the globals graph. Loop over all nodes, eliminating
// completely unreachable nodes, and moving visited nodes to the globals graph
//
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.
N->dropAllReferences(); // Drop all outgoing edges
while (!N->getReferrers().empty())
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
} else { // Otherwise, delete the node
assert(((N->NodeType & DSNode::GlobalNode) == 0 ||
(Flags & DSGraph::RemoveUnreachableGlobals))
&& "Killing a global?");
while (!N->getReferrers().empty()) // Rewrite referrers
N->getReferrers().back()->setNode(0);
delete N;
delete N; // Usecount is zero
}
}
// Now that the nodes have either been deleted or moved to the globals graph,
// loop over the scalarmap, updating the entries for globals...
//
if (!(Flags & DSGraph::RemoveUnreachableGlobals)) { // Not in the TD pass?
// In this array we start the remapping, which can cause merging. Because
// of this, the DSNode pointers in GlobalNodes may be invalidated, so we
// must always go through the ScalarMap (which contains DSNodeHandles [which
// cannot be invalidated by merging]).
//
for (unsigned i = 0, e = GlobalNodes.size(); i != e; ++i) {
Value *G = GlobalNodes[i].first;
hash_map<Value*, DSNodeHandle>::iterator I = ScalarMap.find(G);
assert(I != ScalarMap.end() && "Global not in scalar map anymore?");
assert(I->second.getNode() && "Global not pointing to anything?");
assert(!Alive.count(I->second.getNode()) && "Node is alive??");
GlobalsGraph->ScalarMap[G].mergeWith(I->second);
assert(GlobalsGraph->ScalarMap[G].getNode() &&
"Global not pointing to anything?");
ScalarMap.erase(I);
}
// Merging leaves behind silly nodes, we remove them to avoid polluting the
// globals graph.
GlobalsGraph->removeTriviallyDeadNodes();
} else {
// If we are in the top-down pass, remove all unreachable globals from the
// ScalarMap...
for (unsigned i = 0, e = GlobalNodes.size(); i != e; ++i)
ScalarMap.erase(GlobalNodes[i].first);
}
DEBUG(AssertGraphOK(); GlobalsGraph->AssertGraphOK());
}
void DSGraph::AssertGraphOK() const {
for (hash_map<Value*, DSNodeHandle>::const_iterator I = ScalarMap.begin(),
E = ScalarMap.end(); I != E; ++I) {
assert(I->second.getNode() && "Null node in scalarmap!");
AssertNodeInGraph(I->second.getNode());
if (GlobalValue *GV = dyn_cast<GlobalValue>(I->first)) {
assert((I->second.getNode()->NodeType & DSNode::GlobalNode) &&
"Global points to node, but node isn't global?");
AssertNodeContainsGlobal(I->second.getNode(), GV);
}
}
AssertCallNodesInGraph();
AssertAuxCallNodesInGraph();
}
#if 0
//===----------------------------------------------------------------------===//
// GlobalDSGraph Implementation
@ -1110,6 +1121,30 @@ void DSGraph::removeDeadNodes(unsigned Flags) {
// 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.