1 //===- BottomUpClosure.cpp - Compute bottom-up interprocedural closure ----===//
3 // This file implements the BUDataStructures class, which represents the
4 // Bottom-Up Interprocedural closure of the data structure graph over the
5 // program. This is useful for applications like pool allocation, but **not**
6 // applications like alias analysis.
8 //===----------------------------------------------------------------------===//
10 #include "llvm/Analysis/DataStructure.h"
11 #include "llvm/Module.h"
12 #include "Support/Statistic.h"
13 #include "Support/Debug.h"
14 #include "DSCallSiteIterator.h"
17 Statistic<> MaxSCC("budatastructure", "Maximum SCC Size in Call Graph");
18 Statistic<> NumBUInlines("budatastructures", "Number of graphs inlined");
19 Statistic<> NumCallEdges("budatastructures", "Number of 'actual' call edges");
21 RegisterAnalysis<BUDataStructures>
22 X("budatastructure", "Bottom-up Data Structure Analysis");
27 // run - Calculate the bottom up data structure graphs for each function in the
30 bool BUDataStructures::run(Module &M) {
31 LocalDataStructures &LocalDSA = getAnalysis<LocalDataStructures>();
32 GlobalsGraph = new DSGraph(LocalDSA.getGlobalsGraph());
33 GlobalsGraph->setPrintAuxCalls();
35 Function *MainFunc = M.getMainFunction();
37 calculateReachableGraphs(MainFunc);
39 // Calculate the graphs for any functions that are unreachable from main...
40 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
41 if (!I->isExternal() && !DSInfo.count(I)) {
44 std::cerr << "*** Function unreachable from main: "
45 << I->getName() << "\n";
47 calculateReachableGraphs(I); // Calculate all graphs...
50 NumCallEdges += ActualCallees.size();
52 // At the end of the bottom-up pass, the globals graph becomes complete.
53 // FIXME: This is not the right way to do this, but it is sorta better than
54 // nothing! In particular, externally visible globals and unresolvable call
55 // nodes at the end of the BU phase should make things that they point to
56 // incomplete in the globals graph.
58 GlobalsGraph->maskIncompleteMarkers();
62 void BUDataStructures::calculateReachableGraphs(Function *F) {
63 std::vector<Function*> Stack;
64 hash_map<Function*, unsigned> ValMap;
66 calculateGraphs(F, Stack, NextID, ValMap);
69 DSGraph &BUDataStructures::getOrCreateGraph(Function *F) {
70 // Has the graph already been created?
71 DSGraph *&Graph = DSInfo[F];
72 if (Graph) return *Graph;
74 // Copy the local version into DSInfo...
75 Graph = new DSGraph(getAnalysis<LocalDataStructures>().getDSGraph(*F));
77 Graph->setGlobalsGraph(GlobalsGraph);
78 Graph->setPrintAuxCalls();
80 // Start with a copy of the original call sites...
81 Graph->getAuxFunctionCalls() = Graph->getFunctionCalls();
85 unsigned BUDataStructures::calculateGraphs(Function *F,
86 std::vector<Function*> &Stack,
88 hash_map<Function*, unsigned> &ValMap) {
89 assert(ValMap.find(F) == ValMap.end() && "Shouldn't revisit functions!");
90 unsigned Min = NextID++, MyID = Min;
94 if (F->isExternal()) { // sprintf, fprintf, sscanf, etc...
101 DSGraph &Graph = getOrCreateGraph(F);
103 // The edges out of the current node are the call site targets...
104 for (DSCallSiteIterator I = DSCallSiteIterator::begin_aux(Graph),
105 E = DSCallSiteIterator::end_aux(Graph); I != E; ++I) {
106 Function *Callee = *I;
108 // Have we visited the destination function yet?
109 hash_map<Function*, unsigned>::iterator It = ValMap.find(Callee);
110 if (It == ValMap.end()) // No, visit it now.
111 M = calculateGraphs(Callee, Stack, NextID, ValMap);
112 else // Yes, get it's number.
114 if (M < Min) Min = M;
117 assert(ValMap[F] == MyID && "SCC construction assumption wrong!");
119 return Min; // This is part of a larger SCC!
121 // If this is a new SCC, process it now.
122 if (Stack.back() == F) { // Special case the single "SCC" case here.
123 DEBUG(std::cerr << "Visiting single node SCC #: " << MyID << " fn: "
124 << F->getName() << "\n");
126 DSGraph &G = getDSGraph(*F);
127 DEBUG(std::cerr << " [BU] Calculating graph for: " << F->getName()<< "\n");
129 DEBUG(std::cerr << " [BU] Done inlining: " << F->getName() << " ["
130 << G.getGraphSize() << "+" << G.getAuxFunctionCalls().size()
133 if (MaxSCC < 1) MaxSCC = 1;
135 // Should we revisit the graph?
136 if (DSCallSiteIterator::begin_aux(G) != DSCallSiteIterator::end_aux(G)) {
138 return calculateGraphs(F, Stack, NextID, ValMap);
145 // SCCFunctions - Keep track of the functions in the current SCC
147 hash_set<Function*> SCCFunctions;
150 std::vector<Function*>::iterator FirstInSCC = Stack.end();
151 DSGraph *SCCGraph = 0;
155 SCCFunctions.insert(NF);
157 // Figure out which graph is the largest one, in order to speed things up
158 // a bit in situations where functions in the SCC have widely different
160 DSGraph &NFGraph = getDSGraph(*NF);
161 if (!SCCGraph || SCCGraph->getGraphSize() < NFGraph.getGraphSize())
165 std::cerr << "Calculating graph for SCC #: " << MyID << " of size: "
166 << SCCFunctions.size() << "\n";
168 // Compute the Max SCC Size...
169 if (MaxSCC < SCCFunctions.size())
170 MaxSCC = SCCFunctions.size();
172 // First thing first, collapse all of the DSGraphs into a single graph for
173 // the entire SCC. We computed the largest graph, so clone all of the other
174 // (smaller) graphs into it. Discard all of the old graphs.
176 for (hash_set<Function*>::iterator I = SCCFunctions.begin(),
177 E = SCCFunctions.end(); I != E; ++I) {
178 DSGraph &G = getDSGraph(**I);
179 if (&G != SCCGraph) {
180 DSGraph::NodeMapTy NodeMap;
181 SCCGraph->cloneInto(G, SCCGraph->getScalarMap(),
182 SCCGraph->getReturnNodes(), NodeMap, 0);
183 // Update the DSInfo map and delete the old graph...
184 DSInfo[*I] = SCCGraph;
189 // Clean up the graph before we start inlining a bunch again...
190 SCCGraph->removeTriviallyDeadNodes();
192 // Now that we have one big happy family, resolve all of the call sites in
194 calculateGraph(*SCCGraph);
195 DEBUG(std::cerr << " [BU] Done inlining SCC [" << SCCGraph->getGraphSize()
196 << "+" << SCCGraph->getAuxFunctionCalls().size() << "]\n");
198 std::cerr << "DONE with SCC #: " << MyID << "\n";
200 // We never have to revisit "SCC" processed functions...
202 // Drop the stuff we don't need from the end of the stack
203 Stack.erase(FirstInSCC, Stack.end());
207 return MyID; // == Min
211 // releaseMemory - If the pass pipeline is done with this pass, we can release
212 // our memory... here...
214 void BUDataStructures::releaseMemory() {
215 for (hash_map<Function*, DSGraph*>::iterator I = DSInfo.begin(),
216 E = DSInfo.end(); I != E; ++I) {
217 I->second->getReturnNodes().erase(I->first);
218 if (I->second->getReturnNodes().empty())
222 // Empty map so next time memory is released, data structures are not
229 void BUDataStructures::calculateGraph(DSGraph &Graph) {
230 // Move our call site list into TempFCs so that inline call sites go into the
231 // new call site list and doesn't invalidate our iterators!
232 std::vector<DSCallSite> TempFCs;
233 std::vector<DSCallSite> &AuxCallsList = Graph.getAuxFunctionCalls();
234 TempFCs.swap(AuxCallsList);
236 DSGraph::ReturnNodesTy &ReturnNodes = Graph.getReturnNodes();
238 // Loop over all of the resolvable call sites
239 unsigned LastCallSiteIdx = ~0U;
240 for (DSCallSiteIterator I = DSCallSiteIterator::begin(TempFCs),
241 E = DSCallSiteIterator::end(TempFCs); I != E; ++I) {
242 // If we skipped over any call sites, they must be unresolvable, copy them
243 // to the real call site list.
245 for (; LastCallSiteIdx < I.getCallSiteIdx(); ++LastCallSiteIdx)
246 AuxCallsList.push_back(TempFCs[LastCallSiteIdx]);
247 LastCallSiteIdx = I.getCallSiteIdx();
249 // Resolve the current call...
250 Function *Callee = *I;
251 DSCallSite CS = I.getCallSite();
253 if (Callee->isExternal()) {
254 // Ignore this case, simple varargs functions we cannot stub out!
255 } else if (ReturnNodes.find(Callee) != ReturnNodes.end()) {
256 // Self recursion... simply link up the formal arguments with the
257 // actual arguments...
258 DEBUG(std::cerr << " Self Inlining: " << Callee->getName() << "\n");
260 // Handle self recursion by resolving the arguments and return value
261 Graph.mergeInGraph(CS, *Callee, Graph, 0);
264 ActualCallees.insert(std::make_pair(CS.getCallSite().getInstruction(),
267 // Get the data structure graph for the called function.
269 DSGraph &GI = getDSGraph(*Callee); // Graph to inline
271 DEBUG(std::cerr << " Inlining graph for " << Callee->getName()
272 << "[" << GI.getGraphSize() << "+"
273 << GI.getAuxFunctionCalls().size() << "] into '"
274 << Graph.getFunctionNames() << "' [" << Graph.getGraphSize() << "+"
275 << Graph.getAuxFunctionCalls().size() << "]\n");
277 // Handle self recursion by resolving the arguments and return value
278 Graph.mergeInGraph(CS, *Callee, GI,
279 DSGraph::KeepModRefBits |
280 DSGraph::StripAllocaBit | DSGraph::DontCloneCallNodes);
284 Graph.writeGraphToFile(std::cerr, "bu_" + F.getName() + "_after_" +
290 // Make sure to catch any leftover unresolvable calls...
291 for (++LastCallSiteIdx; LastCallSiteIdx < TempFCs.size(); ++LastCallSiteIdx)
292 AuxCallsList.push_back(TempFCs[LastCallSiteIdx]);
296 // Re-materialize nodes from the globals graph.
297 // Do not ignore globals inlined from callees -- they are not up-to-date!
298 Graph.getInlinedGlobals().clear();
299 Graph.updateFromGlobalGraph();
301 // Recompute the Incomplete markers
302 Graph.maskIncompleteMarkers();
303 Graph.markIncompleteNodes(DSGraph::MarkFormalArgs);
305 // Delete dead nodes. Treat globals that are unreachable but that can
306 // reach live nodes as live.
307 Graph.removeDeadNodes(DSGraph::KeepUnreachableGlobals);
309 //Graph.writeGraphToFile(std::cerr, "bu_" + F.getName());