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 PointerVal &FromPtr,
35 const PointerValSet &ToVals) {
36 assert(FromPtr.Index == 0 &&
37 "Resolved node return pointer should be index 0!");
38 DSNode *N = FromPtr.Node;
40 // Make everything that pointed to the shadow node also point to the values in
43 for (unsigned i = 0, e = ToVals.size(); i != e; ++i)
44 copyEdgesFromTo(ToVals[i], N);
46 // Make everything that pointed to the shadow node now also point to the
47 // values it is equivalent to...
48 const vector<PointerValSet*> &PVSToUpdate(N->getReferrers());
49 for (unsigned i = 0, e = PVSToUpdate.size(); i != e; ++i)
50 PVSToUpdate[i]->add(ToVals);
54 // ResolveNodeTo - The specified node is now known to point to the set of values
55 // in ToVals, instead of the old shadow node subgraph that it was pointing to.
57 static void ResolveNodeTo(DSNode *Node, const PointerValSet &ToVals) {
58 assert(Node->getNumLinks() == 1 && "Resolved node can only be a scalar!!");
60 const PointerValSet &PVS = Node->getLink(0);
62 // Only resolve the first pointer, although there many be many pointers here.
63 // The problem is that the inlined function might return one of the arguments
64 // to the function, and if so, extra values can be added to the arg or call
65 // node that point to what the other one got resolved to. Since these will
66 // be added to the end of the PVS pointed in, we just ignore them.
68 ResolveNodesTo(PVS[0], ToVals);
71 // isResolvableCallNode - Return true if node is a call node and it is a call
72 // node that we can inline...
74 static bool isResolvableCallNode(CallDSNode *CN) {
75 // Only operate on call nodes with direct method calls
76 Function *F = CN->getCall()->getCalledFunction();
77 if (F == 0) return false;
79 // Only work on call nodes with direct calls to methods with bodies.
80 return !F->isExternal();
84 // computeClosure - Replace all of the resolvable call nodes with the contents
85 // of their corresponding method data structure graph...
87 void FunctionDSGraph::computeClosure(const DataStructure &DS) {
88 // Note that this cannot be a real vector because the keys will be changing
89 // as nodes are eliminated!
91 typedef pair<vector<PointerValSet>, CallInst *> CallDescriptor;
92 vector<pair<CallDescriptor, PointerValSet> > CallMap;
94 unsigned NumInlines = 0;
96 // Loop over the resolvable call nodes...
97 vector<CallDSNode*>::iterator NI;
98 NI = std::find_if(CallNodes.begin(), CallNodes.end(), isResolvableCallNode);
99 while (NI != CallNodes.end()) {
100 CallDSNode *CN = *NI;
101 Function *F = CN->getCall()->getCalledFunction();
103 if (NumInlines++ == 100) { // CUTE hack huh?
104 cerr << "Infinite (?) recursion halted\n";
108 CallNodes.erase(NI); // Remove the call node from the graph
110 unsigned CallNodeOffset = NI-CallNodes.begin();
112 // Find out if we have already incorporated this node... if so, it will be
117 cerr << "\nSearching for: " << (void*)CN->getCall() << ": ";
118 for (unsigned X = 0; X != CN->getArgs().size(); ++X) {
119 cerr << " " << X << " is\n";
120 CN->getArgs().first[X].print(cerr);
124 const vector<PointerValSet> &Args = CN->getArgs();
125 PointerValSet *CMI = 0;
126 for (unsigned i = 0, e = CallMap.size(); i != e; ++i) {
128 cerr << "Found: " << (void*)CallMap[i].first.second << ": ";
129 for (unsigned X = 0; X != CallMap[i].first.first.size(); ++X) {
130 cerr << " " << X << " is\n"; CallMap[i].first.first[X].print(cerr);
134 // Look to see if the function call takes a superset of the values we are
135 // providing as input
137 CallDescriptor &CD = CallMap[i].first;
138 if (CD.second == CN->getCall() && CD.first.size() == Args.size()) {
139 bool FoundMismatch = false;
140 for (unsigned j = 0, je = Args.size(); j != je; ++j) {
141 PointerValSet ArgSet = CD.first[j];
142 if (ArgSet.add(Args[j])) {
143 FoundMismatch = true; break;
147 if (!FoundMismatch) { CMI = &CallMap[i].second; break; }
151 // Hold the set of values that correspond to the incorporated methods
154 PointerValSet RetVals;
157 // We have already inlined an identical function call!
160 // Get the datastructure graph for the new method. Note that we are not
161 // allowed to modify this graph because it will be the cached graph that
162 // is returned by other users that want the local datastructure graph for
165 const FunctionDSGraph &NewFunction = DS.getDSGraph(F);
167 // StartNode - The first node of the incorporated graph, last node of the
168 // preexisting data structure graph...
170 unsigned StartArgNode = ArgNodes.size();
171 unsigned StartAllocNode = AllocNodes.size();
173 // Incorporate a copy of the called function graph into the current graph,
174 // allowing us to do local transformations to local graph to link
175 // arguments to call values, and call node to return value...
177 RetVals = cloneFunctionIntoSelf(NewFunction, false);
178 CallMap.push_back(make_pair(CallDescriptor(CN->getArgs(), CN->getCall()),
181 // If the call node has arguments, process them now!
182 if (CN->getNumArgs()) {
183 // The ArgNodes of the incorporated graph should be the nodes starting
184 // at StartNode, ordered the same way as the call arguments. The arg
185 // nodes are seperated by a single shadow node, but that shadow node
186 // might get eliminated in the process of optimization.
188 for (unsigned i = 0, e = CN->getNumArgs(); i != e; ++i) {
189 // Get the arg node of the incorporated method...
190 ArgDSNode *ArgNode = ArgNodes[StartArgNode];
192 // Now we make all of the nodes inside of the incorporated method
193 // point to the real arguments values, not to the shadow nodes for the
196 ResolveNodeTo(ArgNode, CN->getArgValues(i));
198 // Remove the argnode from the set of nodes in this method...
199 ArgNodes.erase(ArgNodes.begin()+StartArgNode);
201 // ArgNode is no longer useful, delete now!
206 // Loop through the nodes, deleting alloca nodes in the inlined function.
207 // Since the memory has been released, we cannot access their pointer
208 // fields (with defined results at least), so it is not possible to use
209 // any pointers to the alloca. Drop them now, and remove the alloca's
210 // since they are dead (we just removed all links to them).
212 for (unsigned i = StartAllocNode; i != AllocNodes.size(); ++i)
213 if (AllocNodes[i]->isAllocaNode()) {
214 AllocDSNode *NDS = AllocNodes[i];
215 NDS->removeAllIncomingEdges(); // These edges are invalid now
216 delete NDS; // Node is dead
217 AllocNodes.erase(AllocNodes.begin()+i); // Remove slot in Nodes array
218 --i; // Don't skip the next node
222 // If the function returns a pointer value... Resolve values pointing to
223 // the shadow nodes pointed to by CN to now point the values in RetVals...
225 if (CN->getNumLinks()) ResolveNodeTo(CN, RetVals);
227 // Now the call node is completely destructable. Eliminate it now.
232 // Eliminate shadow nodes that are not distinguishable from some other
233 // node in the graph...
235 Changed = UnlinkUndistinguishableNodes();
237 // Eliminate shadow nodes that are now extraneous due to linking...
238 Changed |= RemoveUnreachableNodes();
241 //if (F == Func) return; // Only do one self inlining
243 // Move on to the next call node...
244 NI = std::find_if(CallNodes.begin(), CallNodes.end(), isResolvableCallNode);