1 //===- TopDownClosure.cpp - Compute the top-down interprocedure closure ---===//
3 // This file implements the TDDataStructures class, which represents the
4 // Top-down Interprocedural closure of the data structure graph over the
5 // program. This is useful (but not strictly necessary?) for applications
6 // like pointer analysis.
8 //===----------------------------------------------------------------------===//
10 #include "llvm/Analysis/DataStructure.h"
11 #include "llvm/Analysis/DSGraph.h"
12 #include "llvm/Module.h"
13 #include "llvm/DerivedTypes.h"
14 #include "Support/Statistic.h"
16 static RegisterAnalysis<TDDataStructures>
17 Y("tddatastructure", "Top-down Data Structure Analysis Closure");
19 // releaseMemory - If the pass pipeline is done with this pass, we can release
20 // our memory... here...
22 void TDDataStructures::releaseMemory() {
23 for (std::map<const Function*, DSGraph*>::iterator I = DSInfo.begin(),
24 E = DSInfo.end(); I != E; ++I)
27 // Empty map so next time memory is released, data structures are not
32 // run - Calculate the top down data structure graphs for each function in the
35 bool TDDataStructures::run(Module &M) {
36 BUDataStructures &BU = getAnalysis<BUDataStructures>();
38 // Calculate top-down from main...
39 if (Function *F = M.getMainFunction())
42 // Next calculate the graphs for each function unreachable function...
43 for (Module::reverse_iterator I = M.rbegin(), E = M.rend(); I != E; ++I)
49 /// ResolveCallSite - This method is used to link the actual arguments together
50 /// with the formal arguments for a function call in the top-down closure. This
51 /// method assumes that the call site arguments have been mapped into nodes
52 /// local to the specified graph.
54 void TDDataStructures::ResolveCallSite(DSGraph &Graph,
55 const DSCallSite &CallSite) {
56 // Resolve all of the function formal arguments...
57 Function &F = Graph.getFunction();
58 Function::aiterator AI = F.abegin();
60 for (unsigned i = 0, e = CallSite.getNumPtrArgs(); i != e; ++i, ++AI) {
61 // Advance the argument iterator to the first pointer argument...
62 while (!DS::isPointerType(AI->getType())) ++AI;
64 // TD ...Merge the formal arg scalar with the actual arg node
65 DSNodeHandle &NodeForFormal = Graph.getNodeForValue(AI);
66 assert(NodeForFormal.getNode() && "Pointer argument has no dest node!");
67 NodeForFormal.mergeWith(CallSite.getPtrArg(i));
70 // Merge returned node in the caller with the "return" node in callee
71 if (CallSite.getRetVal().getNode() && Graph.getRetNode().getNode())
72 Graph.getRetNode().mergeWith(CallSite.getRetVal());
75 DSGraph &TDDataStructures::getOrCreateDSGraph(Function &F) {
76 DSGraph *&G = DSInfo[&F];
77 if (G == 0) { // Not created yet? Clone BU graph...
78 G = new DSGraph(getAnalysis<BUDataStructures>().getDSGraph(F));
79 G->getAuxFunctionCalls().clear();
84 void TDDataStructures::calculateGraph(Function &F) {
85 // Make sure this graph has not already been calculated, and that we don't get
86 // into an infinite loop with mutually recursive functions.
88 if (GraphDone.count(&F)) return;
91 // Get the current functions graph...
92 DSGraph &Graph = getOrCreateDSGraph(F);
94 const std::vector<DSCallSite> &CallSites = Graph.getFunctionCalls();
95 if (CallSites.empty()) {
96 DEBUG(std::cerr << " [TD] No callees for: " << F.getName() << "\n");
97 return; // If no call sites, the graph is the same as the BU graph!
100 // Loop over all of the call sites, building a multi-map from Callees to
101 // DSCallSite*'s. With this map we can then loop over each callee, cloning
102 // this graph once into it, then resolving arguments.
104 std::multimap<Function*, const DSCallSite*> CalleeSites;
105 for (unsigned i = 0, e = CallSites.size(); i != e; ++i) {
106 const DSCallSite &CS = CallSites[i];
107 const std::vector<GlobalValue*> Callees =
108 CS.getCallee().getNode()->getGlobals();
110 // Loop over all of the functions that this call may invoke...
111 for (unsigned c = 0, e = Callees.size(); c != e; ++c)
112 if (Function *F = dyn_cast<Function>(Callees[c])) // If this is a fn...
113 if (!F->isExternal()) // If it's not external
114 CalleeSites.insert(std::make_pair(F, &CS)); // Keep track of it!
117 // Now that we have information about all of the callees, propogate the
118 // current graph into the callees.
120 DEBUG(std::cerr << " [TD] Inlining '" << F.getName() << "' into "
121 << CalleeSites.size() << " callees.\n");
123 // Loop over all the callees...
124 for (std::multimap<Function*, const DSCallSite*>::iterator
125 I = CalleeSites.begin(), E = CalleeSites.end(); I != E; )
126 if (I->first == &F) { // Bottom-up pass takes care of self loops!
129 // For each callee...
130 Function *Callee = I->first;
131 DSGraph &CG = getOrCreateDSGraph(*Callee); // Get the callee's graph...
133 DEBUG(std::cerr << "\t [TD] Inlining into callee '" << Callee->getName()
136 // Clone our current graph into the callee...
137 std::map<Value*, DSNodeHandle> OldValMap;
138 std::map<const DSNode*, DSNodeHandle> OldNodeMap;
139 CG.cloneInto(Graph, OldValMap, OldNodeMap,
140 DSGraph::KeepAllocaBit | DSGraph::DontCloneCallNodes);
141 OldValMap.clear(); // We don't care about the ValMap
143 // Loop over all of the invocation sites of the callee, resolving
144 // arguments to our graph. This loop may iterate multiple times if the
145 // current function calls this callee multiple times with different
148 for (; I != E && I->first == Callee; ++I) {
149 // Map call site into callee graph
150 DSCallSite NewCS(*I->second, OldNodeMap);
152 // Resolve the return values...
153 NewCS.getRetVal().mergeWith(CG.getRetNode());
155 // Resolve all of the arguments...
156 Function::aiterator AI = Callee->abegin();
157 for (unsigned i = 0, e = NewCS.getNumPtrArgs(); i != e; ++i, ++AI) {
158 // Advance the argument iterator to the first pointer argument...
159 while (!DS::isPointerType(AI->getType())) {
162 if (AI == Callee->aend())
163 std::cerr << "Bad call to Function: " << Callee->getName()<< "\n";
165 assert(AI != Callee->aend() &&
166 "# Args provided is not # Args required!");
169 // Add the link from the argument scalar to the provided value
170 DSNodeHandle &NH = CG.getNodeForValue(AI);
171 assert(NH.getNode() && "Pointer argument without scalarmap entry?");
172 NH.mergeWith(NewCS.getPtrArg(i));
176 // Done with the nodemap...
179 // Recompute the Incomplete markers and eliminate unreachable nodes.
180 CG.maskIncompleteMarkers();
181 CG.markIncompleteNodes(/*markFormals*/ !F.hasInternalLinkage()
182 /*&& FIXME: NEED TO CHECK IF ALL CALLERS FOUND!*/);
183 CG.removeDeadNodes(false, true) ;///*KeepAllGlobals*/ false, true);
184 ///*KeepCalls*/ false);
187 DEBUG(std::cerr << " [TD] Done inlining into callees for: " << F.getName()
188 << " [" << Graph.getGraphSize() << "+"
189 << Graph.getFunctionCalls().size() << "]\n");
192 // Loop over all the callees... making sure they are all resolved now...
193 Function *LastFunc = 0;
194 for (std::multimap<Function*, const DSCallSite*>::iterator
195 I = CalleeSites.begin(), E = CalleeSites.end(); I != E; ++I)
196 if (I->first != LastFunc) { // Only visit each callee once...
198 calculateGraph(*I->first);