1 //===- TopDownClosure.cpp - Compute the top-down interprocedure closure ---===//
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 file implements the TDDataStructures class, which represents the
11 // Top-down Interprocedural closure of the data structure graph over the
12 // program. This is useful (but not strictly necessary?) for applications
13 // like pointer analysis.
15 //===----------------------------------------------------------------------===//
17 #include "llvm/Analysis/DataStructure/DataStructure.h"
18 #include "llvm/Module.h"
19 #include "llvm/DerivedTypes.h"
20 #include "llvm/Analysis/DataStructure/DSGraph.h"
21 #include "llvm/Support/Debug.h"
22 #include "llvm/Support/Timer.h"
23 #include "llvm/ADT/Statistic.h"
28 #define TIME_REGION(VARNAME, DESC) \
29 NamedRegionTimer VARNAME(DESC)
31 #define TIME_REGION(VARNAME, DESC)
35 RegisterAnalysis<TDDataStructures> // Register the pass
36 Y("tddatastructure", "Top-down Data Structure Analysis");
38 Statistic<> NumTDInlines("tddatastructures", "Number of graphs inlined");
41 void TDDataStructures::markReachableFunctionsExternallyAccessible(DSNode *N,
42 hash_set<DSNode*> &Visited) {
43 if (!N || Visited.count(N)) return;
46 for (unsigned i = 0, e = N->getNumLinks(); i != e; ++i) {
47 DSNodeHandle &NH = N->getLink(i*N->getPointerSize());
48 if (DSNode *NN = NH.getNode()) {
49 std::vector<Function*> Functions;
50 NN->addFullFunctionList(Functions);
51 ArgsRemainIncomplete.insert(Functions.begin(), Functions.end());
52 markReachableFunctionsExternallyAccessible(NN, Visited);
58 // run - Calculate the top down data structure graphs for each function in the
61 bool TDDataStructures::runOnModule(Module &M) {
62 BUInfo = &getAnalysis<BUDataStructures>();
63 GlobalECs = BUInfo->getGlobalECs();
64 GlobalsGraph = new DSGraph(BUInfo->getGlobalsGraph(), GlobalECs);
65 GlobalsGraph->setPrintAuxCalls();
67 // Figure out which functions must not mark their arguments complete because
68 // they are accessible outside this compilation unit. Currently, these
69 // arguments are functions which are reachable by global variables in the
71 const DSScalarMap &GGSM = GlobalsGraph->getScalarMap();
72 hash_set<DSNode*> Visited;
73 for (DSScalarMap::global_iterator I=GGSM.global_begin(), E=GGSM.global_end();
75 DSNode *N = GGSM.find(*I)->second.getNode();
76 if (N->isIncomplete())
77 markReachableFunctionsExternallyAccessible(N, Visited);
80 // Loop over unresolved call nodes. Any functions passed into (but not
81 // returned!) from unresolvable call nodes may be invoked outside of the
83 for (DSGraph::afc_iterator I = GlobalsGraph->afc_begin(),
84 E = GlobalsGraph->afc_end(); I != E; ++I)
85 for (unsigned arg = 0, e = I->getNumPtrArgs(); arg != e; ++arg)
86 markReachableFunctionsExternallyAccessible(I->getPtrArg(arg).getNode(),
90 // Functions without internal linkage also have unknown incoming arguments!
91 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
92 if (!I->isExternal() && !I->hasInternalLinkage())
93 ArgsRemainIncomplete.insert(I);
95 // We want to traverse the call graph in reverse post-order. To do this, we
96 // calculate a post-order traversal, then reverse it.
97 hash_set<DSGraph*> VisitedGraph;
98 std::vector<DSGraph*> PostOrder;
101 {TIME_REGION(XXX, "td:Copy graphs");
103 // Visit each of the graphs in reverse post-order now!
104 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
105 if (!I->isExternal())
106 getOrCreateDSGraph(*I);
112 {TIME_REGION(XXX, "td:Compute postorder");
114 // Calculate top-down from main...
115 if (Function *F = M.getMainFunction())
116 ComputePostOrder(*F, VisitedGraph, PostOrder);
118 // Next calculate the graphs for each unreachable function...
119 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
120 ComputePostOrder(*I, VisitedGraph, PostOrder);
122 VisitedGraph.clear(); // Release memory!
125 {TIME_REGION(XXX, "td:Inline stuff");
127 // Visit each of the graphs in reverse post-order now!
128 while (!PostOrder.empty()) {
129 InlineCallersIntoGraph(*PostOrder.back());
130 PostOrder.pop_back();
134 // Free the IndCallMap.
135 while (!IndCallMap.empty()) {
136 delete IndCallMap.begin()->second;
137 IndCallMap.erase(IndCallMap.begin());
141 ArgsRemainIncomplete.clear();
142 GlobalsGraph->removeTriviallyDeadNodes();
148 DSGraph &TDDataStructures::getOrCreateDSGraph(Function &F) {
149 DSGraph *&G = DSInfo[&F];
150 if (G == 0) { // Not created yet? Clone BU graph...
151 G = new DSGraph(getAnalysis<BUDataStructures>().getDSGraph(F), GlobalECs,
152 DSGraph::DontCloneAuxCallNodes);
153 assert(G->getAuxFunctionCalls().empty() && "Cloned aux calls?");
154 G->setPrintAuxCalls();
155 G->setGlobalsGraph(GlobalsGraph);
157 // Note that this graph is the graph for ALL of the function in the SCC, not
159 for (DSGraph::retnodes_iterator RI = G->retnodes_begin(),
160 E = G->retnodes_end(); RI != E; ++RI)
162 DSInfo[RI->first] = G;
168 void TDDataStructures::ComputePostOrder(Function &F,hash_set<DSGraph*> &Visited,
169 std::vector<DSGraph*> &PostOrder) {
170 if (F.isExternal()) return;
171 DSGraph &G = getOrCreateDSGraph(F);
172 if (Visited.count(&G)) return;
175 // Recursively traverse all of the callee graphs.
176 for (DSGraph::fc_iterator CI = G.fc_begin(), CE = G.fc_end(); CI != CE; ++CI){
177 Instruction *CallI = CI->getCallSite().getInstruction();
178 for (BUDataStructures::callee_iterator I = BUInfo->callee_begin(CallI),
179 E = BUInfo->callee_end(CallI); I != E; ++I)
180 ComputePostOrder(*I->second, Visited, PostOrder);
183 PostOrder.push_back(&G);
190 // releaseMemory - If the pass pipeline is done with this pass, we can release
191 // our memory... here...
193 // FIXME: This should be releaseMemory and will work fine, except that LoadVN
194 // has no way to extend the lifetime of the pass, which screws up ds-aa.
196 void TDDataStructures::releaseMyMemory() {
197 for (hash_map<Function*, DSGraph*>::iterator I = DSInfo.begin(),
198 E = DSInfo.end(); I != E; ++I) {
199 I->second->getReturnNodes().erase(I->first);
200 if (I->second->getReturnNodes().empty())
204 // Empty map so next time memory is released, data structures are not
211 /// InlineCallersIntoGraph - Inline all of the callers of the specified DS graph
212 /// into it, then recompute completeness of nodes in the resultant graph.
213 void TDDataStructures::InlineCallersIntoGraph(DSGraph &DSG) {
214 // Inline caller graphs into this graph. First step, get the list of call
215 // sites that call into this graph.
216 std::vector<CallerCallEdge> EdgesFromCaller;
217 std::map<DSGraph*, std::vector<CallerCallEdge> >::iterator
218 CEI = CallerEdges.find(&DSG);
219 if (CEI != CallerEdges.end()) {
220 std::swap(CEI->second, EdgesFromCaller);
221 CallerEdges.erase(CEI);
224 // Sort the caller sites to provide a by-caller-graph ordering.
225 std::sort(EdgesFromCaller.begin(), EdgesFromCaller.end());
228 // Merge information from the globals graph into this graph. FIXME: This is
229 // stupid. Instead of us cloning information from the GG into this graph,
230 // then having RemoveDeadNodes clone it back, we should do all of this as a
231 // post-pass over all of the graphs. We need to take cloning out of
232 // removeDeadNodes and gut removeDeadNodes at the same time first though. :(
234 DSGraph &GG = *DSG.getGlobalsGraph();
235 ReachabilityCloner RC(DSG, GG,
236 DSGraph::DontCloneCallNodes |
237 DSGraph::DontCloneAuxCallNodes);
238 for (DSScalarMap::global_iterator
239 GI = DSG.getScalarMap().global_begin(),
240 E = DSG.getScalarMap().global_end(); GI != E; ++GI)
241 RC.getClonedNH(GG.getNodeForValue(*GI));
244 DEBUG(std::cerr << "[TD] Inlining callers into '" << DSG.getFunctionNames()
247 // Iteratively inline caller graphs into this graph.
248 while (!EdgesFromCaller.empty()) {
249 DSGraph &CallerGraph = *EdgesFromCaller.back().CallerGraph;
251 // Iterate through all of the call sites of this graph, cloning and merging
252 // any nodes required by the call.
253 ReachabilityCloner RC(DSG, CallerGraph,
254 DSGraph::DontCloneCallNodes |
255 DSGraph::DontCloneAuxCallNodes);
257 // Inline all call sites from this caller graph.
259 const DSCallSite &CS = *EdgesFromCaller.back().CS;
260 Function &CF = *EdgesFromCaller.back().CalledFunction;
261 DEBUG(std::cerr << " [TD] Inlining graph into Fn '"
262 << CF.getName() << "' from ");
263 if (CallerGraph.getReturnNodes().empty())
264 DEBUG(std::cerr << "SYNTHESIZED INDIRECT GRAPH");
266 DEBUG (std::cerr << "Fn '"
267 << CS.getCallSite().getInstruction()->
268 getParent()->getParent()->getName() << "'");
269 DEBUG(std::cerr << ": " << CF.getFunctionType()->getNumParams()
272 // Get the formal argument and return nodes for the called function and
273 // merge them with the cloned subgraph.
274 DSCallSite T1 = DSG.getCallSiteForArguments(CF);
275 RC.mergeCallSite(T1, CS);
278 EdgesFromCaller.pop_back();
279 } while (!EdgesFromCaller.empty() &&
280 EdgesFromCaller.back().CallerGraph == &CallerGraph);
284 // Next, now that this graph is finalized, we need to recompute the
285 // incompleteness markers for this graph and remove unreachable nodes.
286 DSG.maskIncompleteMarkers();
288 // If any of the functions has incomplete incoming arguments, don't mark any
289 // of them as complete.
290 bool HasIncompleteArgs = false;
291 for (DSGraph::retnodes_iterator I = DSG.retnodes_begin(),
292 E = DSG.retnodes_end(); I != E; ++I)
293 if (ArgsRemainIncomplete.count(I->first)) {
294 HasIncompleteArgs = true;
298 // Recompute the Incomplete markers. Depends on whether args are complete
300 = HasIncompleteArgs ? DSGraph::MarkFormalArgs : DSGraph::IgnoreFormalArgs;
301 DSG.markIncompleteNodes(Flags | DSGraph::IgnoreGlobals);
303 // Delete dead nodes. Treat globals that are unreachable as dead also.
304 DSG.removeDeadNodes(DSGraph::RemoveUnreachableGlobals);
306 // We are done with computing the current TD Graph! Finally, before we can
307 // finish processing this function, we figure out which functions it calls and
308 // records these call graph edges, so that we have them when we process the
310 if (DSG.fc_begin() == DSG.fc_end()) return;
312 // Loop over all the call sites and all the callees at each call site, and add
313 // edges to the CallerEdges structure for each callee.
314 for (DSGraph::fc_iterator CI = DSG.fc_begin(), E = DSG.fc_end();
317 // Handle direct calls efficiently.
318 if (CI->isDirectCall()) {
319 if (!CI->getCalleeFunc()->isExternal() &&
320 !DSG.getReturnNodes().count(CI->getCalleeFunc()))
321 CallerEdges[&getDSGraph(*CI->getCalleeFunc())]
322 .push_back(CallerCallEdge(&DSG, &*CI, CI->getCalleeFunc()));
326 Instruction *CallI = CI->getCallSite().getInstruction();
327 // For each function in the invoked function list at this call site...
328 BUDataStructures::callee_iterator IPI =
329 BUInfo->callee_begin(CallI), IPE = BUInfo->callee_end(CallI);
331 // Skip over all calls to this graph (SCC calls).
332 while (IPI != IPE && &getDSGraph(*IPI->second) == &DSG)
336 if (IPI == IPE) continue;
338 Function *FirstCallee = IPI->second;
341 // Skip over more SCC calls.
342 while (IPI != IPE && &getDSGraph(*IPI->second) == &DSG)
345 // If there is exactly one callee from this call site, remember the edge in
348 if (!FirstCallee->isExternal())
349 CallerEdges[&getDSGraph(*FirstCallee)]
350 .push_back(CallerCallEdge(&DSG, &*CI, FirstCallee));
354 // Otherwise, there are multiple callees from this call site, so it must be
355 // an indirect call. Chances are that there will be other call sites with
356 // this set of targets. If so, we don't want to do M*N inlining operations,
357 // so we build up a new, private, graph that represents the calls of all
358 // calls to this set of functions.
359 std::vector<Function*> Callees;
360 for (BUDataStructures::ActualCalleesTy::const_iterator I =
361 BUInfo->callee_begin(CallI), E = BUInfo->callee_end(CallI);
363 if (!I->second->isExternal())
364 Callees.push_back(I->second);
365 std::sort(Callees.begin(), Callees.end());
367 std::map<std::vector<Function*>, DSGraph*>::iterator IndCallRecI =
368 IndCallMap.lower_bound(Callees);
370 DSGraph *IndCallGraph;
372 // If we already have this graph, recycle it.
373 if (IndCallRecI != IndCallMap.end() && IndCallRecI->first == Callees) {
374 std::cerr << " [TD] *** Reuse of indcall graph for " << Callees.size()
376 IndCallGraph = IndCallRecI->second;
378 // Otherwise, create a new DSGraph to represent this.
379 IndCallGraph = new DSGraph(DSG.getGlobalECs(), DSG.getTargetData());
381 // Make a nullary dummy call site, which will eventually get some content
382 // merged into it. The actual callee function doesn't matter here, so we
383 // just pass it something to keep the ctor happy.
384 std::vector<DSNodeHandle> ArgDummyVec;
385 DSCallSite DummyCS(CI->getCallSite(), DSNodeHandle(), Callees[0]/*dummy*/,
387 IndCallGraph->getFunctionCalls().push_back(DummyCS);
389 IndCallRecI = IndCallMap.insert(IndCallRecI,
390 std::make_pair(Callees, IndCallGraph));
392 // Additionally, make sure that each of the callees inlines this graph
394 DSCallSite *NCS = &IndCallGraph->getFunctionCalls().front();
395 for (unsigned i = 0, e = Callees.size(); i != e; ++i) {
396 DSGraph& CalleeGraph = getDSGraph(*Callees[i]);
397 if (&CalleeGraph != &DSG)
398 CallerEdges[&CalleeGraph].push_back(CallerCallEdge(IndCallGraph, NCS,
403 // Now that we know which graph to use for this, merge the caller
404 // information into the graph, based on information from the call site.
405 ReachabilityCloner RC(*IndCallGraph, DSG, 0);
406 RC.mergeCallSite(IndCallGraph->getFunctionCalls().front(), *CI);
411 static const Function *getFnForValue(const Value *V) {
412 if (const Instruction *I = dyn_cast<Instruction>(V))
413 return I->getParent()->getParent();
414 else if (const Argument *A = dyn_cast<Argument>(V))
415 return A->getParent();
416 else if (const BasicBlock *BB = dyn_cast<BasicBlock>(V))
417 return BB->getParent();
421 void TDDataStructures::deleteValue(Value *V) {
422 if (const Function *F = getFnForValue(V)) { // Function local value?
423 // If this is a function local value, just delete it from the scalar map!
424 getDSGraph(*F).getScalarMap().eraseIfExists(V);
428 if (Function *F = dyn_cast<Function>(V)) {
429 assert(getDSGraph(*F).getReturnNodes().size() == 1 &&
430 "cannot handle scc's");
436 assert(!isa<GlobalVariable>(V) && "Do not know how to delete GV's yet!");
439 void TDDataStructures::copyValue(Value *From, Value *To) {
440 if (From == To) return;
441 if (const Function *F = getFnForValue(From)) { // Function local value?
442 // If this is a function local value, just delete it from the scalar map!
443 getDSGraph(*F).getScalarMap().copyScalarIfExists(From, To);
447 if (Function *FromF = dyn_cast<Function>(From)) {
448 Function *ToF = cast<Function>(To);
449 assert(!DSInfo.count(ToF) && "New Function already exists!");
450 DSGraph *NG = new DSGraph(getDSGraph(*FromF), GlobalECs);
452 assert(NG->getReturnNodes().size() == 1 && "Cannot copy SCC's yet!");
454 // Change the Function* is the returnnodes map to the ToF.
455 DSNodeHandle Ret = NG->retnodes_begin()->second;
456 NG->getReturnNodes().clear();
457 NG->getReturnNodes()[ToF] = Ret;
461 if (const Function *F = getFnForValue(To)) {
462 DSGraph &G = getDSGraph(*F);
463 G.getScalarMap().copyScalarIfExists(From, To);
469 assert(0 && "Do not know how to copy this yet!");