aboutsummaryrefslogtreecommitdiffstats
path: root/lib/Analysis
diff options
context:
space:
mode:
Diffstat (limited to 'lib/Analysis')
-rw-r--r--lib/Analysis/DataStructure/DataStructure.cpp339
1 files changed, 167 insertions, 172 deletions
diff --git a/lib/Analysis/DataStructure/DataStructure.cpp b/lib/Analysis/DataStructure/DataStructure.cpp
index cc43544..175cc8a 100644
--- a/lib/Analysis/DataStructure/DataStructure.cpp
+++ b/lib/Analysis/DataStructure/DataStructure.cpp
@@ -502,6 +502,7 @@ Function &DSCallSite::getCaller() const {
//===----------------------------------------------------------------------===//
DSGraph::DSGraph(const DSGraph &G) : Func(G.Func), GlobalsGraph(0) {
+ PrintAuxCalls = false;
std::map<const DSNode*, DSNodeHandle> NodeMap;
RetNode = cloneInto(G, ScalarMap, NodeMap);
}
@@ -509,6 +510,7 @@ DSGraph::DSGraph(const DSGraph &G) : Func(G.Func), GlobalsGraph(0) {
DSGraph::DSGraph(const DSGraph &G,
std::map<const DSNode*, DSNodeHandle> &NodeMap)
: Func(G.Func), GlobalsGraph(0) {
+ PrintAuxCalls = false;
RetNode = cloneInto(G, ScalarMap, NodeMap);
}
@@ -738,7 +740,7 @@ void DSGraph::markIncompleteNodes(bool markFormalArgs) {
// Then the return value is certainly incomplete!
markIncompleteNode(Call.getRetVal().getNode());
- // All objects pointed to by function arguments are incomplete though!
+ // All objects pointed to by function arguments are incomplete!
for (unsigned i = 0, e = Call.getNumPtrArgs(); i != e; ++i)
markIncompleteNode(Call.getPtrArg(i).getNode());
}
@@ -747,7 +749,6 @@ void DSGraph::markIncompleteNodes(bool markFormalArgs) {
for (unsigned i = 0, e = Nodes.size(); i != e; ++i)
if (Nodes[i]->NodeType & DSNode::GlobalNode) {
DSNode *N = Nodes[i];
- // FIXME: Make more efficient by looking over Links directly
for (unsigned i = 0, e = N->getSize(); i < e; i += DS::PointerSize)
if (DSNode *DSN = N->getLink(i).getNode())
markIncompleteNode(DSN);
@@ -771,21 +772,23 @@ static void removeRefsToGlobal(DSNode* N,
// dead.
//
bool DSGraph::isNodeDead(DSNode *N) {
- // Is it a trivially dead shadow node...
- if (N->getReferrers().empty() && (N->NodeType & ~DSNode::DEAD) == 0)
- return true;
-
- // Is it a function node or some other trivially unused global?
- if ((N->NodeType & ~DSNode::GlobalNode) == 0 && N->getSize() == 0 &&
- N->getReferrers().size() == N->getGlobals().size()) {
+ // Is it a trivially dead shadow node?
+ return N->getReferrers().empty() && (N->NodeType & ~DSNode::DEAD) == 0
+}
- // Remove the globals from the ScalarMap, so that the referrer count will go
- // down to zero.
- removeRefsToGlobal(N, ScalarMap);
- assert(N->getReferrers().empty() && "Referrers should all be gone now!");
- return true;
- }
+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->NodeType & ~DSNode::Incomplete) == 0 && // No interesting info?
+ N->getType().Ty == Type::VoidTy && !N->isNodeCompletelyFolded())
+ Edge.setNode(0); // Kill the edge!
+}
+static inline bool nodeContainsExternalFunction(const DSNode *N) {
+ const std::vector<GlobalValue*> &Globals = N->getGlobals();
+ for (unsigned i = 0, e = Globals.size(); i != e; ++i)
+ if (Globals[i]->isExternal())
+ return true;
return false;
}
@@ -793,7 +796,51 @@ static void removeIdenticalCalls(vector<DSCallSite> &Calls,
const std::string &where) {
// Remove trivially identical function calls
unsigned NumFns = Calls.size();
- std::sort(Calls.begin(), Calls.end());
+ std::sort(Calls.begin(), Calls.end()); // Sort by callee as primary key!
+
+ // Scan the call list cleaning it up as necessary...
+ DSNode *LastCalleeNode = 0;
+ unsigned NumDuplicateCalls = 0;
+ bool LastCalleeContainsExternalFunction = false;
+ for (unsigned i = 0, e = Calls.size(); i != e; ++i) {
+ DSCallSite &CS = Calls[i];
+
+ // If the return value or any arguments point to a void node with no
+ // information at all in it, and the call node is the only node to point
+ // to it, remove the edge to the node (killing the node).
+ //
+ killIfUselessEdge(CS.getRetVal());
+ for (unsigned a = 0, e = CS.getNumPtrArgs(); a != e; ++a)
+ killIfUselessEdge(CS.getPtrArg(a));
+
+ // If this call site calls the same function as the last call site, and if
+ // the function pointer contains an external function, this node will never
+ // be resolved. Merge the arguments of the call node because no information
+ // will be lost.
+ //
+ if (CS.getCallee().getNode() == LastCalleeNode) {
+ ++NumDuplicateCalls;
+ if (NumDuplicateCalls == 1) {
+ LastCalleeContainsExternalFunction =
+ nodeContainsExternalFunction(LastCalleeNode);
+ }
+
+ if (LastCalleeContainsExternalFunction ||
+ // This should be more than enough context sensitivity!
+ // FIXME: Evaluate how many times this is tripped!
+ NumDuplicateCalls > 20) {
+ DSCallSite &OCS = Calls[i-1];
+ OCS.getRetVal().mergeWith(CS.getRetVal());
+ for (unsigned a = 0, e = CS.getNumPtrArgs(); a != e; ++a)
+ OCS.getPtrArg(a).mergeWith(CS.getPtrArg(a));
+ // The node will now be eliminated as a duplicate!
+ }
+ } else {
+ LastCalleeNode = CS.getCallee().getNode();
+ NumDuplicateCalls = 0;
+ }
+ }
+
Calls.erase(std::unique(Calls.begin(), Calls.end()),
Calls.end());
@@ -805,20 +852,21 @@ static void removeIdenticalCalls(vector<DSCallSite> &Calls,
<< " call nodes in " << where << "\n";);
}
+
// removeTriviallyDeadNodes - After the graph has been constructed, this method
// removes all unreachable nodes that are created because they got merged with
// other nodes in the graph. These nodes will all be trivially unreachable, so
// we don't have to perform any non-trivial analysis here.
//
void DSGraph::removeTriviallyDeadNodes() {
- for (unsigned i = 0; i != Nodes.size(); ++i)
- if (!(Nodes[i]->NodeType & DSNode::GlobalNode))
- if (isNodeDead(Nodes[i])) { // This node is dead!
- delete Nodes[i]; // Free memory...
- Nodes.erase(Nodes.begin()+i--); // Remove from node list...
- }
-
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...
+ Nodes.erase(Nodes.begin()+i--); // Remove from node list...
+ }
}
@@ -827,152 +875,65 @@ void DSGraph::removeTriviallyDeadNodes() {
//
static void markAlive(DSNode *N, std::set<DSNode*> &Alive) {
if (N == 0) return;
+ std::set<DSNode*>::iterator I = Alive.lower_bound(N);
+ if (I != Alive.end() && *I == N) return; // Already marked alive
+ Alive.insert(I, N); // Is alive now
- Alive.insert(N);
for (unsigned i = 0, e = N->getSize(); i < e; i += DS::PointerSize)
- if (DSNode *DSN = N->getLink(i).getNode())
- if (!Alive.count(DSN))
- markAlive(DSN, Alive);
+ markAlive(N->getLink(i).getNode(), Alive);
}
-static bool checkGlobalAlive(DSNode *N, std::set<DSNode*> &Alive,
- std::set<DSNode*> &Visiting) {
+// markAliveIfCanReachAlive - Simple graph walker that recursively traverses the
+// graph looking for a node that is marked alive. If the node is marked alive,
+// the recursive unwind marks node alive that can point to the alive node. This
+// is basically just a post-order traversal.
+//
+// This function returns true if the specified node is alive.
+//
+static bool markAliveIfCanReachAlive(DSNode *N, std::set<DSNode*> &Alive,
+ std::set<DSNode*> &Visited) {
if (N == 0) return false;
- if (Visiting.count(N)) return false; // terminate recursion on a cycle
- Visiting.insert(N);
-
- // If any immediate successor is alive, N is alive
- for (unsigned i = 0, e = N->getSize(); i < e; i += DS::PointerSize)
- if (DSNode *DSN = N->getLink(i).getNode())
- if (Alive.count(DSN)) {
- Visiting.erase(N);
- return true;
- }
-
- // Else if any successor reaches a live node, N is alive
- for (unsigned i = 0, e = N->getSize(); i < e; i += DS::PointerSize)
- if (DSNode *DSN = N->getLink(i).getNode())
- if (checkGlobalAlive(DSN, Alive, Visiting)) {
- Visiting.erase(N); return true;
- }
-
- Visiting.erase(N);
- return false;
-}
+ // If we know that this node is alive, return so!
+ if (Alive.count(N)) return true;
+ // Otherwise, we don't think the node is alive yet, check for infinite
+ // recursion.
+ std::set<DSNode*>::iterator VI = Visited.lower_bound(N);
+ if (VI != Visited.end() && *VI == N) return false; // Found a cycle
+ // No recursion, insert into Visited...
+ Visited.insert(VI, N);
-// markGlobalsIteration - Recursive helper function for markGlobalsAlive().
-// This would be unnecessary if function calls were real nodes! In that case,
-// the simple iterative loop in the first few lines below suffice.
-//
-static void markGlobalsIteration(std::set<DSNode*>& GlobalNodes,
- vector<DSCallSite> &Calls,
- std::set<DSNode*> &Alive,
- bool FilterCalls) {
-
- // Iterate, marking globals or cast nodes alive until no new live nodes
- // are added to Alive
- std::set<DSNode*> Visiting; // Used to identify cycles
- std::set<DSNode*>::iterator I = GlobalNodes.begin(), E = GlobalNodes.end();
- for (size_t liveCount = 0; liveCount < Alive.size(); ) {
- liveCount = Alive.size();
- for ( ; I != E; ++I)
- if (Alive.count(*I) == 0) {
- Visiting.clear();
- if (checkGlobalAlive(*I, Alive, Visiting))
- markAlive(*I, Alive);
- }
- }
+ if (N->NodeType & DSNode::GlobalNode)
+ return false; // Global nodes will be marked on their own
- // Find function calls with some dead and some live nodes.
- // Since all call nodes must be live if any one is live, we have to mark
- // all nodes of the call as live and continue the iteration (via recursion).
- if (FilterCalls) {
- bool Recurse = false;
- for (unsigned i = 0, ei = Calls.size(); i < ei; ++i) {
- bool CallIsDead = true, CallHasDeadArg = false;
- DSCallSite &CS = Calls[i];
- for (unsigned j = 0, ej = CS.getNumPtrArgs(); j != ej; ++j)
- if (DSNode *N = CS.getPtrArg(j).getNode()) {
- bool ArgIsDead = !Alive.count(N);
- CallHasDeadArg |= ArgIsDead;
- CallIsDead &= ArgIsDead;
- }
-
- if (DSNode *N = CS.getRetVal().getNode()) {
- bool RetIsDead = !Alive.count(N);
- CallHasDeadArg |= RetIsDead;
- CallIsDead &= RetIsDead;
- }
+ bool ChildrenAreAlive = false;
- DSNode *N = CS.getCallee().getNode();
- bool FnIsDead = !Alive.count(N);
- CallHasDeadArg |= FnIsDead;
- CallIsDead &= FnIsDead;
-
- if (!CallIsDead && CallHasDeadArg) {
- // Some node in this call is live and another is dead.
- // Mark all nodes of call as live and iterate once more.
- Recurse = true;
- for (unsigned j = 0, ej = CS.getNumPtrArgs(); j != ej; ++j)
- markAlive(CS.getPtrArg(j).getNode(), Alive);
- markAlive(CS.getRetVal().getNode(), Alive);
- markAlive(CS.getCallee().getNode(), Alive);
- }
- }
- if (Recurse)
- markGlobalsIteration(GlobalNodes, Calls, Alive, FilterCalls);
- }
+ for (unsigned i = 0, e = N->getSize(); i < e; i += DS::PointerSize)
+ ChildrenAreAlive |= markAliveIfCanReachAlive(N->getLink(i).getNode(),
+ Alive, Visited);
+ if (ChildrenAreAlive)
+ markAlive(N, Alive);
+ return ChildrenAreAlive;
}
+static bool CallSiteUsesAliveArgs(DSCallSite &CS, std::set<DSNode*> &Alive,
+ std::set<DSNode*> &Visited) {
+ if (markAliveIfCanReachAlive(CS.getRetVal().getNode(), Alive, Visited) ||
+ markAliveIfCanReachAlive(CS.getCallee().getNode(), Alive, Visited))
+ return true;
+ for (unsigned j = 0, e = CS.getNumPtrArgs(); j != e; ++j)
+ if (markAliveIfCanReachAlive(CS.getPtrArg(j).getNode(), Alive, Visited))
+ return true;
+ return false;
+}
-// markGlobalsAlive - Mark global nodes and cast nodes alive if they
-// can reach any other live node. Since this can produce new live nodes,
-// we use a simple iterative algorithm.
-//
-static void markGlobalsAlive(DSGraph &G, std::set<DSNode*> &Alive,
- bool FilterCalls) {
- // Add global and cast nodes to a set so we don't walk all nodes every time
- std::set<DSNode*> GlobalNodes;
- for (unsigned i = 0, e = G.getNodes().size(); i != e; ++i)
- if (G.getNodes()[i]->NodeType & DSNode::GlobalNode)
- GlobalNodes.insert(G.getNodes()[i]);
-
- // Add all call nodes to the same set
- vector<DSCallSite> &Calls = G.getAuxFunctionCalls();
- if (FilterCalls) {
- for (unsigned i = 0, e = Calls.size(); i != e; ++i) {
- for (unsigned j = 0, e = Calls[i].getNumPtrArgs(); j != e; ++j)
- if (DSNode *N = Calls[i].getPtrArg(j).getNode())
- GlobalNodes.insert(N);
- if (DSNode *N = Calls[i].getRetVal().getNode())
- GlobalNodes.insert(N);
- if (DSNode *N = Calls[i].getCallee().getNode())
- GlobalNodes.insert(N);
- }
- }
-
- // Iterate and recurse until no new live node are discovered.
- // This would be a simple iterative loop if function calls were real nodes!
- markGlobalsIteration(GlobalNodes, Calls, Alive, FilterCalls);
-
- // Free up references to dead globals from the ScalarMap
- std::set<DSNode*>::iterator I = GlobalNodes.begin(), E = GlobalNodes.end();
- for( ; I != E; ++I)
- if (Alive.count(*I) == 0)
- removeRefsToGlobal(*I, G.getScalarMap());
-
- // Delete dead function calls
- if (FilterCalls)
- for (int ei = Calls.size(), i = ei-1; i >= 0; --i) {
- bool CallIsDead = true;
- for (unsigned j = 0, ej = Calls[i].getNumPtrArgs();
- CallIsDead && j != ej; ++j)
- CallIsDead = Alive.count(Calls[i].getPtrArg(j).getNode()) == 0;
- if (CallIsDead)
- Calls.erase(Calls.begin() + i); // remove the call entirely
- }
+static void markAlive(DSCallSite &CS, std::set<DSNode*> &Alive) {
+ markAlive(CS.getRetVal().getNode(), Alive);
+ markAlive(CS.getCallee().getNode(), Alive);
+
+ for (unsigned j = 0, e = CS.getNumPtrArgs(); j != e; ++j)
+ markAlive(CS.getPtrArg(j).getNode(), Alive);
}
// removeDeadNodes - Use a more powerful reachability analysis to eliminate
@@ -989,29 +950,63 @@ void DSGraph::removeDeadNodes() {
// Alive - a set that holds all nodes found to be reachable/alive.
std::set<DSNode*> Alive;
+ std::vector<std::pair<Value*, DSNode*> > GlobalNodes;
- // If KeepCalls, mark all nodes reachable by call nodes as alive...
- for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i) {
- for (unsigned j = 0, e = FunctionCalls[i].getNumPtrArgs(); j != e; ++j)
- markAlive(FunctionCalls[i].getPtrArg(j).getNode(), Alive);
- markAlive(FunctionCalls[i].getRetVal().getNode(), Alive);
- markAlive(FunctionCalls[i].getCallee().getNode(), Alive);
- }
- for (unsigned i = 0, e = AuxFunctionCalls.size(); i != e; ++i) {
- for (unsigned j = 0, e = AuxFunctionCalls[i].getNumPtrArgs(); j != e; ++j)
- markAlive(AuxFunctionCalls[i].getPtrArg(j).getNode(), Alive);
- markAlive(AuxFunctionCalls[i].getRetVal().getNode(), Alive);
- markAlive(AuxFunctionCalls[i].getCallee().getNode(), Alive);
- }
-
- // Mark all nodes reachable by scalar nodes as alive...
+ // Mark all nodes reachable by (non-global) scalar nodes as alive...
for (std::map<Value*, DSNodeHandle>::iterator I = ScalarMap.begin(),
E = ScalarMap.end(); I != E; ++I)
- markAlive(I->second.getNode(), Alive);
+ if (!isa<GlobalValue>(I->first)) // Don't mark globals!
+ markAlive(I->second.getNode(), Alive);
+ else // Keep track of global nodes
+ GlobalNodes.push_back(std::make_pair(I->first, I->second.getNode()));
// The return value is alive as well...
markAlive(RetNode.getNode(), Alive);
+ // If any global nodes points to a non-global that is "alive", the global is
+ // "alive" as well...
+ //
+ std::set<DSNode*> Visited;
+ for (unsigned i = 0, e = GlobalNodes.size(); i != e; ++i)
+ markAliveIfCanReachAlive(GlobalNodes[i].second, Alive, Visited);
+
+ std::vector<bool> FCallsAlive(FunctionCalls.size());
+ for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i)
+ if (CallSiteUsesAliveArgs(FunctionCalls[i], Alive, Visited)) {
+ markAlive(FunctionCalls[i], Alive);
+ FCallsAlive[i] = true;
+ }
+
+ std::vector<bool> AuxFCallsAlive(AuxFunctionCalls.size());
+ for (unsigned i = 0, e = AuxFunctionCalls.size(); i != e; ++i)
+ if (CallSiteUsesAliveArgs(AuxFunctionCalls[i], Alive, Visited)) {
+ markAlive(AuxFunctionCalls[i], Alive);
+ AuxFCallsAlive[i] = 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());
+
+ // Remove all dead aux function calls...
+ 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...
+ 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...
vector<DSNode*> DeadNodes;
DeadNodes.reserve(Nodes.size()); // Only one allocation is allowed.
generated by cgit v1.1 at 2024-07-31 04:24:07 +0000