1 //===- EquivClassGraphs.cpp - Merge equiv-class graphs & inline bottom-up -===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This pass is the same as the complete bottom-up graphs, but
11 // with functions partitioned into equivalence classes and a single merged
12 // DS graph for all functions in an equivalence class. After this merging,
13 // graphs are inlined bottom-up on the SCCs of the final (CBU) call graph.
15 //===----------------------------------------------------------------------===//
17 #define DEBUG_TYPE "ECGraphs"
18 #include "EquivClassGraphs.h"
19 #include "llvm/Module.h"
20 #include "llvm/Pass.h"
21 #include "llvm/Analysis/DataStructure/DSGraph.h"
22 #include "llvm/Analysis/DataStructure/DataStructure.h"
23 #include "llvm/Support/CallSite.h"
24 #include "llvm/Support/Debug.h"
25 #include "llvm/ADT/SCCIterator.h"
26 #include "llvm/ADT/Statistic.h"
27 #include "llvm/ADT/EquivalenceClasses.h"
28 #include "llvm/ADT/STLExtras.h"
32 RegisterAnalysis<PA::EquivClassGraphs> X("equivdatastructure",
33 "Equivalence-class Bottom-up Data Structure Analysis");
34 Statistic<> NumEquivBUInlines("equivdatastructures",
35 "Number of graphs inlined");
36 Statistic<> NumFoldGraphInlines("Inline equiv-class graphs bottom up",
37 "Number of graphs inlined");
42 static void CheckAllGraphs(Module *M, GT &ECGraphs) {
43 DSGraph &GG = ECGraphs.getGlobalsGraph();
45 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
46 if (!I->isExternal()) {
47 DSGraph &G = ECGraphs.getDSGraph(*I);
49 DSGraph::NodeMapTy GlobalsGraphNodeMapping;
50 for (DSScalarMap::global_iterator I = G.getScalarMap().global_begin(),
51 E = G.getScalarMap().global_end(); I != E; ++I)
52 DSGraph::computeNodeMapping(G.getNodeForValue(*I),
53 GG.getNodeForValue(*I),
54 GlobalsGraphNodeMapping);
59 // getDSGraphForCallSite - Return the common data structure graph for
60 // callees at the specified call site.
62 Function *PA::EquivClassGraphs::
63 getSomeCalleeForCallSite(const CallSite &CS) const {
64 Function *thisFunc = CS.getCaller();
65 assert(thisFunc && "getDSGraphForCallSite(): Not a valid call site?");
66 DSGraph &DSG = getDSGraph(*thisFunc);
67 DSNode *calleeNode = DSG.getNodeForValue(CS.getCalledValue()).getNode();
68 std::map<DSNode*, Function *>::const_iterator I =
69 OneCalledFunction.find(calleeNode);
70 return (I == OneCalledFunction.end())? NULL : I->second;
73 // runOnModule - Calculate the bottom up data structure graphs for each function
76 bool PA::EquivClassGraphs::runOnModule(Module &M) {
77 CBU = &getAnalysis<CompleteBUDataStructures>();
78 CheckAllGraphs(&M, *CBU);
80 GlobalsGraph = new DSGraph(CBU->getGlobalsGraph());
81 GlobalsGraph->setPrintAuxCalls();
83 ActualCallees = CBU->getActualCallees();
85 // Find equivalence classes of functions called from common call sites.
86 // Fold the CBU graphs for all functions in an equivalence class.
87 buildIndirectFunctionSets(M);
89 // Stack of functions used for Tarjan's SCC-finding algorithm.
90 std::vector<Function*> Stack;
91 std::map<Function*, unsigned> ValMap;
94 if (Function *Main = M.getMainFunction()) {
95 if (!Main->isExternal())
96 processSCC(getOrCreateGraph(*Main), *Main, Stack, NextID, ValMap);
98 std::cerr << "Fold Graphs: No 'main' function found!\n";
101 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
102 if (!I->isExternal() && !ValMap.count(I))
103 processSCC(getOrCreateGraph(*I), *I, Stack, NextID, ValMap);
105 DEBUG(CheckAllGraphs(&M, *this));
107 getGlobalsGraph().removeTriviallyDeadNodes();
112 // buildIndirectFunctionSets - Iterate over the module looking for indirect
113 // calls to functions. If a call site can invoke any functions [F1, F2... FN],
114 // unify the N functions together in the FuncECs set.
116 void PA::EquivClassGraphs::buildIndirectFunctionSets(Module &M) {
117 const ActualCalleesTy& AC = CBU->getActualCallees();
119 // Loop over all of the indirect calls in the program. If a call site can
120 // call multiple different functions, we need to unify all of the callees into
121 // the same equivalence class.
122 Instruction *LastInst = 0;
123 Function *FirstFunc = 0;
124 for (ActualCalleesTy::const_iterator I=AC.begin(), E=AC.end(); I != E; ++I) {
125 if (I->second->isExternal())
126 continue; // Ignore functions we cannot modify
128 CallSite CS = CallSite::get(I->first);
130 if (CS.getCalledFunction()) { // Direct call:
131 FuncECs.addElement(I->second); // -- Make sure function has equiv class
132 FirstFunc = I->second; // -- First callee at this site
133 } else { // Else indirect call
134 // DEBUG(std::cerr << "CALLEE: " << I->second->getName()
135 // << " from : " << I->first);
136 if (I->first != LastInst) {
137 // This is the first callee from this call site.
139 FirstFunc = I->second;
140 // Instead of storing the lastInst For Indirection call Sites we store
141 // the DSNode for the function ptr arguemnt
142 Function *thisFunc = LastInst->getParent()->getParent();
143 DSGraph &TFG = CBU->getDSGraph(*thisFunc);
144 DSNode *calleeNode = TFG.getNodeForValue(CS.getCalledValue()).getNode();
145 OneCalledFunction[calleeNode] = FirstFunc;
146 FuncECs.addElement(I->second);
148 // This is not the first possible callee from a particular call site.
149 // Union the callee in with the other functions.
150 FuncECs.unionSetsWith(FirstFunc, I->second);
152 Function *thisFunc = LastInst->getParent()->getParent();
153 DSGraph &TFG = CBU->getDSGraph(*thisFunc);
154 DSNode *calleeNode = TFG.getNodeForValue(CS.getCalledValue()).getNode();
155 assert(OneCalledFunction.count(calleeNode) > 0 && "Missed a call?");
160 // Now include all functions that share a graph with any function in the
161 // equivalence class. More precisely, if F is in the class, and G(F) is
162 // its graph, then we include all other functions that are also in G(F).
163 // Currently, that is just the functions in the same call-graph-SCC as F.
165 DSGraph& funcDSGraph = CBU->getDSGraph(*I->second);
166 const DSGraph::ReturnNodesTy &RetNodes = funcDSGraph.getReturnNodes();
167 for (DSGraph::ReturnNodesTy::const_iterator RI=RetNodes.begin(),
168 RE=RetNodes.end(); RI != RE; ++RI)
169 FuncECs.unionSetsWith(FirstFunc, RI->first);
172 // Now that all of the equivalences have been built, merge the graphs for
173 // each equivalence class.
175 std::set<Function*> &leaderSet = FuncECs.getLeaderSet();
176 DEBUG(std::cerr << "\nIndirect Function Equivalence Sets:\n");
177 for (std::set<Function*>::iterator LI = leaderSet.begin(),
178 LE = leaderSet.end(); LI != LE; ++LI) {
181 const std::set<Function*>& EqClass = FuncECs.getEqClass(LF);
184 if (EqClass.size() > 1) {
185 DEBUG(std::cerr <<" Equivalence set for leader " <<LF->getName()<<" = ");
186 for (std::set<Function*>::const_iterator EqI = EqClass.begin(),
187 EqEnd = EqClass.end(); EqI != EqEnd; ++EqI)
188 DEBUG(std::cerr << " " << (*EqI)->getName() << ",");
189 DEBUG(std::cerr << "\n");
193 if (EqClass.size() > 1) {
194 // This equiv class has multiple functions: merge their graphs. First,
195 // clone the CBU graph for the leader and make it the common graph for the
196 // equivalence graph.
197 DSGraph *mergedG = &getOrCreateGraph(*LF);
199 // Record the argument nodes for use in merging later below.
200 std::vector<DSNodeHandle> ArgNodes;
202 for (Function::aiterator AI1 = LF->abegin(); AI1 != LF->aend(); ++AI1)
203 if (DS::isPointerType(AI1->getType()))
204 ArgNodes.push_back(mergedG->getNodeForValue(AI1));
206 // Merge in the graphs of all other functions in this equiv. class. Note
207 // that two or more functions may have the same graph, and it only needs
208 // to be merged in once. Use a set to find repetitions.
209 std::set<DSGraph*> GraphsMerged;
210 for (std::set<Function*>::const_iterator EqI = EqClass.begin(),
211 EqEnd = EqClass.end(); EqI != EqEnd; ++EqI) {
213 DSGraph*& FG = DSInfo[F];
215 if (F == LF || FG == mergedG)
218 // Record the "folded" graph for the function.
221 // Clone this member of the equivalence class into mergedG
222 DSGraph* CBUGraph = &CBU->getDSGraph(*F);
223 if (GraphsMerged.count(CBUGraph) > 0)
226 GraphsMerged.insert(CBUGraph);
227 DSGraph::NodeMapTy NodeMap;
229 mergedG->cloneInto(*CBUGraph, mergedG->getScalarMap(),
230 mergedG->getReturnNodes(), NodeMap, 0);
232 // Merge the return nodes of all functions together.
233 mergedG->getReturnNodes()[LF].mergeWith(mergedG->getReturnNodes()[F]);
235 // Merge the function arguments with all argument nodes found so far.
236 // If there are extra function args, add them to the vector of argNodes
237 Function::aiterator AI2 = F->abegin(), AI2end = F->aend();
238 for (unsigned arg=0, numArgs = ArgNodes.size();
239 arg != numArgs && AI2 != AI2end; ++AI2, ++arg)
240 if (DS::isPointerType(AI2->getType()))
241 ArgNodes[arg].mergeWith(mergedG->getNodeForValue(AI2));
243 for ( ; AI2 != AI2end; ++AI2)
244 if (DS::isPointerType(AI2->getType()))
245 ArgNodes.push_back(mergedG->getNodeForValue(AI2));
246 DEBUG(mergedG->AssertGraphOK());
250 DEBUG(std::cerr << "\n");
254 DSGraph &PA::EquivClassGraphs::getOrCreateGraph(Function &F) {
255 // Has the graph already been created?
256 DSGraph *&Graph = DSInfo[&F];
257 if (Graph) return *Graph;
259 DSGraph &CBUGraph = CBU->getDSGraph(F);
261 // Copy the CBU graph...
262 Graph = new DSGraph(CBUGraph); // updates the map via reference
263 Graph->setGlobalsGraph(&getGlobalsGraph());
264 Graph->setPrintAuxCalls();
266 // Make sure to update the DSInfo map for all functions in the graph!
267 for (DSGraph::ReturnNodesTy::iterator I = Graph->getReturnNodes().begin();
268 I != Graph->getReturnNodes().end(); ++I)
269 if (I->first != &F) {
270 DSGraph *&FG = DSInfo[I->first];
271 assert(FG == NULL || FG == &CBU->getDSGraph(*I->first) &&
272 "Merging function in SCC twice?");
280 unsigned PA::EquivClassGraphs::processSCC(DSGraph &FG, Function &F,
281 std::vector<Function*> &Stack,
283 std::map<Function*,unsigned> &ValMap){
284 DEBUG(std::cerr << " ProcessSCC for function " << F.getName() << "\n");
286 std::map<Function*, unsigned>::iterator It = ValMap.lower_bound(&F);
287 if (It != ValMap.end() && It->first == &F)
290 unsigned Min = NextID++, MyID = Min;
294 // The edges out of the current node are the call site targets...
295 for (unsigned i = 0, e = FG.getFunctionCalls().size(); i != e; ++i) {
296 Instruction *Call = FG.getFunctionCalls()[i].getCallSite().getInstruction();
298 // Loop over all of the actually called functions...
299 ActualCalleesTy::const_iterator I, E;
300 for (tie(I, E) = getActualCallees().equal_range(Call); I != E; ++I)
301 if (!I->second->isExternal()) {
302 // Process the callee as necessary.
303 unsigned M = processSCC(getOrCreateGraph(*I->second), *I->second,
304 Stack, NextID, ValMap);
305 if (M < Min) Min = M;
309 assert(ValMap[&F] == MyID && "SCC construction assumption wrong!");
311 return Min; // This is part of a larger SCC!
313 // If this is a new SCC, process it now.
314 bool IsMultiNodeSCC = false;
315 while (Stack.back() != &F) {
316 DSGraph *NG = &getOrCreateGraph(*Stack.back());
317 ValMap[Stack.back()] = ~0U;
319 // Since all SCCs must be the same as those found in CBU, we do not need to
320 // do any merging. Make sure all functions in the SCC share the same graph.
321 assert(NG == &FG && "ECG discovered different SCC's than the CBU pass?");
324 IsMultiNodeSCC = true;
335 /// processGraph - Process the CBU graphs for the program in bottom-up order on
336 /// the SCC of the __ACTUAL__ call graph. This builds final folded CBU graphs.
337 void PA::EquivClassGraphs::processGraph(DSGraph &G, Function &F) {
338 DEBUG(std::cerr << " ProcessGraph for function " << F.getName() << "\n");
340 hash_set<Instruction*> calls;
342 DSGraph* CallerGraph = &getOrCreateGraph(F);
344 // Else we need to inline some callee graph. Visit all call sites.
345 // The edges out of the current node are the call site targets...
346 for (unsigned i=0, e = CallerGraph->getFunctionCalls().size(); i != e; ++i) {
347 const DSCallSite &CS = CallerGraph->getFunctionCalls()[i];
348 Instruction *TheCall = CS.getCallSite().getInstruction();
350 assert(calls.insert(TheCall).second &&
351 "Call instruction occurs multiple times in graph??");
353 // Inline the common callee graph into the current graph, if the callee
354 // graph has not changed. Note that all callees should have the same
355 // graph so we only need to do this once.
357 DSGraph* CalleeGraph = NULL;
358 ActualCalleesTy::const_iterator I, E;
359 tie(I, E) = getActualCallees().equal_range(TheCall);
362 // Loop over all potential callees to find the first non-external callee.
363 for (TNum = 0, Num = std::distance(I, E); I != E; ++I, ++TNum)
364 if (!I->second->isExternal())
367 // Now check if the graph has changed and if so, clone and inline it.
369 Function *CalleeFunc = I->second;
371 // Merge the callee's graph into this graph, if not already the same.
372 // Callees in the same equivalence class (which subsumes those
373 // in the same SCCs) have the same graph. Note that all recursion
374 // including self-recursion have been folded in the equiv classes.
376 CalleeGraph = &getOrCreateGraph(*CalleeFunc);
377 if (CalleeGraph != CallerGraph) {
378 ++NumFoldGraphInlines;
379 CallerGraph->mergeInGraph(CS, *CalleeFunc, *CalleeGraph,
380 DSGraph::KeepModRefBits |
381 DSGraph::StripAllocaBit |
382 DSGraph::DontCloneCallNodes |
383 DSGraph::DontCloneAuxCallNodes);
384 DEBUG(std::cerr << " Inlining graph [" << i << "/" << e-1
385 << ":" << TNum << "/" << Num-1 << "] for "
386 << CalleeFunc->getName() << "["
387 << CalleeGraph->getGraphSize() << "+"
388 << CalleeGraph->getAuxFunctionCalls().size()
389 << "] into '" /*<< CallerGraph->getFunctionNames()*/ << "' ["
390 << CallerGraph->getGraphSize() << "+"
391 << CallerGraph->getAuxFunctionCalls().size()
397 // Now loop over the rest of the callees and make sure they have the
398 // same graph as the one inlined above.
400 for (++I, ++TNum; I != E; ++I, ++TNum)
401 if (!I->second->isExternal())
402 assert(CalleeGraph == &getOrCreateGraph(*I->second) &&
403 "Callees at a call site have different graphs?");
407 // Recompute the Incomplete markers.
408 assert(CallerGraph->getInlinedGlobals().empty());
409 CallerGraph->maskIncompleteMarkers();
410 CallerGraph->markIncompleteNodes(DSGraph::MarkFormalArgs);
412 // Delete dead nodes. Treat globals that are unreachable but that can
413 // reach live nodes as live.
414 CallerGraph->removeDeadNodes(DSGraph::KeepUnreachableGlobals);
416 // When this graph is finalized, clone the globals in the graph into the
417 // globals graph to make sure it has everything, from all graphs.
418 DSScalarMap &MainSM = CallerGraph->getScalarMap();
419 ReachabilityCloner RC(*CallerGraph->getGlobalsGraph(), *CallerGraph,
420 DSGraph::StripAllocaBit);
422 // Clone everything reachable from globals in the function graph into the
424 for (DSScalarMap::global_iterator I = MainSM.global_begin(),
425 E = MainSM.global_end(); I != E; ++I)
426 RC.getClonedNH(MainSM[*I]);
428 DEBUG(std::cerr << " -- DONE ProcessGraph for function "
429 << F.getName() << "\n");