1 //===- ComputeClosure.cpp - Implement interprocedural closing of graphs ---===//
3 // Compute the interprocedural closure of a data structure graph
5 //===----------------------------------------------------------------------===//
7 // DEBUG_IP_CLOSURE - Define this to debug the act of linking up graphs
8 //#define DEBUG_IP_CLOSURE 1
10 #include "llvm/Analysis/DataStructure.h"
11 #include "llvm/Function.h"
12 #include "llvm/iOther.h"
13 #include "Support/STLExtras.h"
16 // Make all of the pointers that point to Val also point to N.
18 static void copyEdgesFromTo(PointerVal Val, DSNode *N) {
19 unsigned ValIdx = Val.Index;
20 unsigned NLinks = N->getNumLinks();
22 const vector<PointerValSet*> &PVSsToUpdate(Val.Node->getReferrers());
23 for (unsigned i = 0, e = PVSsToUpdate.size(); i != e; ++i) {
24 // Loop over all of the pointers pointing to Val...
25 PointerValSet &PVS = *PVSsToUpdate[i];
26 for (unsigned j = 0, je = PVS.size(); j != je; ++j) {
27 if (PVS[j].Node == Val.Node && PVS[j].Index >= ValIdx &&
28 PVS[j].Index < ValIdx+NLinks)
29 PVS.add(PointerVal(N, PVS[j].Index-ValIdx));
34 static void ResolveNodesTo(const PointerValSet &FromVals,
35 const PointerValSet &ToVals) {
36 // Only resolve the first pointer, although there many be many pointers here.
37 // The problem is that the inlined function might return one of the arguments
38 // to the function, and if so, extra values can be added to the arg or call
39 // node that point to what the other one got resolved to. Since these will
40 // be added to the end of the PVS pointed in, we just ignore them.
42 assert(!FromVals.empty() && "From should have at least a shadow node!");
43 const PointerVal &FromPtr = FromVals[0];
45 assert(FromPtr.Index == 0 &&
46 "Resolved node return pointer should be index 0!");
47 DSNode *N = FromPtr.Node;
49 // Make everything that pointed to the shadow node also point to the values in
52 for (unsigned i = 0, e = ToVals.size(); i != e; ++i)
53 copyEdgesFromTo(ToVals[i], N);
55 // Make everything that pointed to the shadow node now also point to the
56 // values it is equivalent to...
57 const vector<PointerValSet*> &PVSToUpdate(N->getReferrers());
58 for (unsigned i = 0, e = PVSToUpdate.size(); i != e; ++i)
59 PVSToUpdate[i]->add(ToVals);
63 // ResolveNodeTo - The specified node is now known to point to the set of values
64 // in ToVals, instead of the old shadow node subgraph that it was pointing to.
66 static void ResolveNodeTo(DSNode *Node, const PointerValSet &ToVals) {
67 assert(Node->getNumLinks() == 1 && "Resolved node can only be a scalar!!");
69 const PointerValSet &PVS = Node->getLink(0);
70 ResolveNodesTo(PVS, ToVals);
73 // isResolvableCallNode - Return true if node is a call node and it is a call
74 // node that we can inline...
76 static bool isResolvableCallNode(CallDSNode *CN) {
77 // Only operate on call nodes with direct function calls
78 if (CN->getArgValues(0).size() == 1 &&
79 isa<GlobalDSNode>(CN->getArgValues(0)[0].Node)) {
80 GlobalDSNode *GDN = cast<GlobalDSNode>(CN->getArgValues(0)[0].Node);
81 Function *F = cast<Function>(GDN->getGlobal());
83 // Only work on call nodes with direct calls to methods with bodies.
84 return !F->isExternal();
89 #include "Support/CommandLine.h"
90 static cl::Int InlineLimit("dsinlinelimit", "Max number of graphs to inline when computing ds closure", cl::Hidden, 100);
92 // computeClosure - Replace all of the resolvable call nodes with the contents
93 // of their corresponding method data structure graph...
95 void FunctionDSGraph::computeClosure(const DataStructure &DS) {
96 // Note that this cannot be a real vector because the keys will be changing
97 // as nodes are eliminated!
99 typedef pair<vector<PointerValSet>, CallInst *> CallDescriptor;
100 vector<pair<CallDescriptor, PointerValSet> > CallMap;
102 unsigned NumInlines = 0;
104 // Loop over the resolvable call nodes...
105 vector<CallDSNode*>::iterator NI;
106 NI = std::find_if(CallNodes.begin(), CallNodes.end(), isResolvableCallNode);
107 while (NI != CallNodes.end()) {
108 CallDSNode *CN = *NI;
109 GlobalDSNode *FGDN = cast<GlobalDSNode>(CN->getArgValues(0)[0].Node);
110 Function *F = cast<Function>(FGDN->getGlobal());
112 if ((int)NumInlines++ == InlineLimit) { // CUTE hack huh?
113 cerr << "Infinite (?) recursion halted\n";
114 cerr << "Not inlining: " << F->getName() << "\n";
120 CallNodes.erase(NI); // Remove the call node from the graph
122 unsigned CallNodeOffset = NI-CallNodes.begin();
124 // Find out if we have already incorporated this node... if so, it will be
129 cerr << "\nSearching for: " << (void*)CN->getCall() << ": ";
130 for (unsigned X = 0; X != CN->getArgs().size(); ++X) {
131 cerr << " " << X << " is\n";
132 CN->getArgs().first[X].print(cerr);
136 const vector<PointerValSet> &Args = CN->getArgs();
137 PointerValSet *CMI = 0;
138 for (unsigned i = 0, e = CallMap.size(); i != e; ++i) {
140 cerr << "Found: " << (void*)CallMap[i].first.second << ": ";
141 for (unsigned X = 0; X != CallMap[i].first.first.size(); ++X) {
142 cerr << " " << X << " is\n"; CallMap[i].first.first[X].print(cerr);
146 // Look to see if the function call takes a superset of the values we are
147 // providing as input
149 CallDescriptor &CD = CallMap[i].first;
150 if (CD.second == CN->getCall() && CD.first.size() == Args.size()) {
151 bool FoundMismatch = false;
152 for (unsigned j = 0, je = Args.size(); j != je; ++j) {
153 PointerValSet ArgSet = CD.first[j];
154 if (ArgSet.add(Args[j])) {
155 FoundMismatch = true; break;
159 if (!FoundMismatch) { CMI = &CallMap[i].second; break; }
163 // Hold the set of values that correspond to the incorporated methods
166 PointerValSet RetVals;
169 // We have already inlined an identical function call!
172 // Get the datastructure graph for the new method. Note that we are not
173 // allowed to modify this graph because it will be the cached graph that
174 // is returned by other users that want the local datastructure graph for
177 const FunctionDSGraph &NewFunction = DS.getDSGraph(F);
179 // StartNode - The first node of the incorporated graph, last node of the
180 // preexisting data structure graph...
182 unsigned StartAllocNode = AllocNodes.size();
184 // Incorporate a copy of the called function graph into the current graph,
185 // allowing us to do local transformations to local graph to link
186 // arguments to call values, and call node to return value...
188 vector<PointerValSet> Args;
189 RetVals = cloneFunctionIntoSelf(NewFunction, false, Args);
190 CallMap.push_back(make_pair(CallDescriptor(CN->getArgs(), CN->getCall()),
193 // If the call node has arguments, process them now!
194 assert(Args.size() == CN->getNumArgs()-1 &&
195 "Call node doesn't match function?");
197 for (unsigned i = 0, e = Args.size(); i != e; ++i) {
198 // Now we make all of the nodes inside of the incorporated method
199 // point to the real arguments values, not to the shadow nodes for the
201 ResolveNodesTo(Args[i], CN->getArgValues(i+1));
204 // Loop through the nodes, deleting alloca nodes in the inlined function.
205 // Since the memory has been released, we cannot access their pointer
206 // fields (with defined results at least), so it is not possible to use
207 // any pointers to the alloca. Drop them now, and remove the alloca's
208 // since they are dead (we just removed all links to them).
210 for (unsigned i = StartAllocNode; i != AllocNodes.size(); ++i)
211 if (AllocNodes[i]->isAllocaNode()) {
212 AllocDSNode *NDS = AllocNodes[i];
213 NDS->removeAllIncomingEdges(); // These edges are invalid now
214 delete NDS; // Node is dead
215 AllocNodes.erase(AllocNodes.begin()+i); // Remove slot in Nodes array
216 --i; // Don't skip the next node
220 // If the function returns a pointer value... Resolve values pointing to
221 // the shadow nodes pointed to by CN to now point the values in RetVals...
223 if (CN->getNumLinks()) ResolveNodeTo(CN, RetVals);
225 // Now the call node is completely destructable. Eliminate it now.
230 // Eliminate shadow nodes that are not distinguishable from some other
231 // node in the graph...
233 Changed = UnlinkUndistinguishableNodes();
235 // Eliminate shadow nodes that are now extraneous due to linking...
236 Changed |= RemoveUnreachableNodes();
239 //if (F == Func) return; // Only do one self inlining
241 // Move on to the next call node...
242 NI = std::find_if(CallNodes.begin(), CallNodes.end(), isResolvableCallNode);
245 // Drop references to globals...
250 // Eliminate shadow nodes that are not distinguishable from some other
251 // node in the graph...
253 Changed = UnlinkUndistinguishableNodes();
255 // Eliminate shadow nodes that are now extraneous due to linking...
256 Changed |= RemoveUnreachableNodes();