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/Module.h"
12 #include "llvm/DerivedTypes.h"
13 #include "Support/Statistic.h"
14 #include "DSCallSiteIterator.h"
17 RegisterAnalysis<TDDataStructures> // Register the pass
18 Y("tddatastructure", "Top-down Data Structure Analysis");
20 Statistic<> NumTDInlines("tddatastructures", "Number of graphs inlined");
23 /// FunctionHasCompleteArguments - This function returns true if it is safe not
24 /// to mark arguments to the function complete.
26 /// FIXME: Need to check if all callers have been found, or rather if a
27 /// funcpointer escapes!
29 static bool FunctionHasCompleteArguments(Function &F) {
30 return F.hasInternalLinkage();
33 // run - Calculate the top down data structure graphs for each function in the
36 bool TDDataStructures::run(Module &M) {
37 BUDataStructures &BU = getAnalysis<BUDataStructures>();
38 GlobalsGraph = new DSGraph(BU.getGlobalsGraph());
40 // Figure out which functions must not mark their arguments complete because
41 // they are accessible outside this compilation unit.
42 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
43 if (!FunctionHasCompleteArguments(*I))
44 ArgsRemainIncomplete.insert(I);
46 // Calculate top-down from main...
47 if (Function *F = M.getMainFunction())
48 calculateGraphFrom(*F);
50 // Next calculate the graphs for each function unreachable function...
51 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
52 if (!I->isExternal() && !DSInfo.count(I))
53 calculateGraphFrom(*I);
55 ArgsRemainIncomplete.clear();
59 // releaseMemory - If the pass pipeline is done with this pass, we can release
60 // our memory... here...
62 // FIXME: This should be releaseMemory and will work fine, except that LoadVN
63 // has no way to extend the lifetime of the pass, which screws up ds-aa.
65 void TDDataStructures::releaseMyMemory() {
66 for (hash_map<Function*, DSGraph*>::iterator I = DSInfo.begin(),
67 E = DSInfo.end(); I != E; ++I) {
68 I->second->getReturnNodes().erase(I->first);
69 if (I->second->getReturnNodes().empty())
73 // Empty map so next time memory is released, data structures are not
81 DSGraph &TDDataStructures::getOrCreateDSGraph(Function &F) {
82 DSGraph *&G = DSInfo[&F];
83 if (G == 0) { // Not created yet? Clone BU graph...
84 G = new DSGraph(getAnalysis<BUDataStructures>().getDSGraph(F));
85 G->getAuxFunctionCalls().clear();
86 G->setPrintAuxCalls();
87 G->setGlobalsGraph(GlobalsGraph);
93 void TDDataStructures::ComputePostOrder(Function &F,hash_set<DSGraph*> &Visited,
94 std::vector<DSGraph*> &PostOrder,
95 const BUDataStructures::ActualCalleesTy &ActualCallees) {
96 if (F.isExternal()) return;
97 DSGraph &G = getOrCreateDSGraph(F);
98 if (Visited.count(&G)) return;
101 // Recursively traverse all of the callee graphs.
102 const std::vector<DSCallSite> &FunctionCalls = G.getFunctionCalls();
104 for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i) {
105 std::pair<BUDataStructures::ActualCalleesTy::const_iterator,
106 BUDataStructures::ActualCalleesTy::const_iterator>
107 IP = ActualCallees.equal_range(&FunctionCalls[i].getCallInst());
109 for (BUDataStructures::ActualCalleesTy::const_iterator I = IP.first;
111 ComputePostOrder(*I->second, Visited, PostOrder, ActualCallees);
114 PostOrder.push_back(&G);
119 void TDDataStructures::calculateGraphFrom(Function &F) {
120 // We want to traverse the call graph in reverse post-order. To do this, we
121 // calculate a post-order traversal, then reverse it.
122 hash_set<DSGraph*> VisitedGraph;
123 std::vector<DSGraph*> PostOrder;
124 ComputePostOrder(F, VisitedGraph, PostOrder,
125 getAnalysis<BUDataStructures>().getActualCallees());
126 VisitedGraph.clear(); // Release memory!
128 // Visit each of the graphs in reverse post-order now!
129 while (!PostOrder.empty()) {
130 inlineGraphIntoCallees(*PostOrder.back());
131 PostOrder.pop_back();
136 void TDDataStructures::inlineGraphIntoCallees(DSGraph &Graph) {
137 // Recompute the Incomplete markers and eliminate unreachable nodes.
138 Graph.maskIncompleteMarkers();
140 // If any of the functions has incomplete incoming arguments, don't mark any
141 // of them as complete.
142 bool HasIncompleteArgs = false;
143 const DSGraph::ReturnNodesTy &GraphReturnNodes = Graph.getReturnNodes();
144 for (DSGraph::ReturnNodesTy::const_iterator I = GraphReturnNodes.begin(),
145 E = GraphReturnNodes.end(); I != E; ++I)
146 if (ArgsRemainIncomplete.count(I->first)) {
147 HasIncompleteArgs = true;
152 = HasIncompleteArgs ? DSGraph::MarkFormalArgs : DSGraph::IgnoreFormalArgs;
153 Graph.markIncompleteNodes(Flags | DSGraph::IgnoreGlobals);
154 Graph.removeDeadNodes(DSGraph::RemoveUnreachableGlobals);
156 const std::vector<DSCallSite> &FunctionCalls = Graph.getFunctionCalls();
157 if (FunctionCalls.empty()) {
158 DEBUG(std::cerr << " [TD] No callees for: " << Graph.getFunctionNames()
163 // Now that we have information about all of the callees, propagate the
164 // current graph into the callees.
166 DEBUG(std::cerr << " [TD] Inlining '" << Graph.getFunctionNames() <<"' into "
167 << FunctionCalls.size() << " call nodes.\n");
169 const BUDataStructures::ActualCalleesTy &ActualCallees =
170 getAnalysis<BUDataStructures>().getActualCallees();
172 // Only inline this function into each real callee once. After that, just
173 // merge information into arguments...
174 hash_map<DSGraph*, DSGraph::NodeMapTy> InlinedSites;
176 // Loop over all the callees... cloning this graph into each one exactly once,
177 // keeping track of the node mapping information...
178 for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i) {
179 // Inline this graph into each function in the invoked function list.
180 std::pair<BUDataStructures::ActualCalleesTy::const_iterator,
181 BUDataStructures::ActualCalleesTy::const_iterator>
182 IP = ActualCallees.equal_range(&FunctionCalls[i].getCallInst());
185 if (IP.first != IP.second) {
186 NumArgs = IP.first->second->getFunctionType()->getNumParams();
187 for (BUDataStructures::ActualCalleesTy::const_iterator I = IP.first;
189 if (NumArgs != (int)I->second->getFunctionType()->getNumParams()) {
196 std::cerr << "ERROR: NONSAME NUMBER OF ARGUMENTS TO CALLEES\n";
199 for (BUDataStructures::ActualCalleesTy::const_iterator I = IP.first;
200 I != IP.second; ++I) {
201 DSGraph &CG = getDSGraph(*I->second);
202 assert(&CG != &Graph && "TD need not inline graph into self!");
204 if (!InlinedSites.count(&CG)) { // If we haven't already inlined into CG
205 DEBUG(std::cerr << " [TD] Inlining graph into callee graph '"
206 << CG.getFunctionNames() << "': " << I->second->getFunctionType()->getNumParams() << " args\n");
207 DSGraph::ScalarMapTy OldScalarMap;
208 DSGraph::ReturnNodesTy ReturnNodes;
209 CG.cloneInto(Graph, OldScalarMap, ReturnNodes, InlinedSites[&CG],
210 DSGraph::StripModRefBits | DSGraph::KeepAllocaBit |
211 DSGraph::DontCloneCallNodes |
212 DSGraph::DontCloneAuxCallNodes);
218 // Loop over all the callees...
219 for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i) {
220 // Inline this graph into each function in the invoked function list.
221 std::pair<BUDataStructures::ActualCalleesTy::const_iterator,
222 BUDataStructures::ActualCalleesTy::const_iterator>
223 IP = ActualCallees.equal_range(&FunctionCalls[i].getCallInst());
224 for (BUDataStructures::ActualCalleesTy::const_iterator I = IP.first;
225 I != IP.second; ++I) {
226 DSGraph &CG = getDSGraph(*I->second);
227 DEBUG(std::cerr << " [TD] Resolving arguments for callee graph '"
228 << CG.getFunctionNames() << "'\n");
230 // Transform our call site information into the cloned version for CG
231 DSCallSite CS(FunctionCalls[i], InlinedSites[&CG]);
233 // Get the arguments bindings for the called function in CG... and merge
234 // them with the cloned graph.
235 CG.getCallSiteForArguments(*I->second).mergeWith(CS);
239 DEBUG(std::cerr << " [TD] Done inlining into callees for: "
240 << Graph.getFunctionNames() << " [" << Graph.getGraphSize() << "+"
241 << Graph.getFunctionCalls().size() << "]\n");