| //===- TopDownClosure.cpp - Compute the top-down interprocedure closure ---===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file was developed by the LLVM research group and is distributed under |
| // the University of Illinois Open Source License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements the TDDataStructures class, which represents the |
| // Top-down Interprocedural closure of the data structure graph over the |
| // program. This is useful (but not strictly necessary?) for applications |
| // like pointer analysis. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/Analysis/DataStructure.h" |
| #include "llvm/Module.h" |
| #include "llvm/DerivedTypes.h" |
| #include "llvm/Analysis/DSGraph.h" |
| #include "Support/Debug.h" |
| #include "Support/Statistic.h" |
| |
| namespace llvm { |
| |
| namespace { |
| RegisterAnalysis<TDDataStructures> // Register the pass |
| Y("tddatastructure", "Top-down Data Structure Analysis"); |
| |
| Statistic<> NumTDInlines("tddatastructures", "Number of graphs inlined"); |
| } |
| |
| void TDDataStructures::markReachableFunctionsExternallyAccessible(DSNode *N, |
| hash_set<DSNode*> &Visited) { |
| if (!N || Visited.count(N)) return; |
| Visited.insert(N); |
| |
| for (unsigned i = 0, e = N->getNumLinks(); i != e; ++i) { |
| DSNodeHandle &NH = N->getLink(i*N->getPointerSize()); |
| if (DSNode *NN = NH.getNode()) { |
| const std::vector<GlobalValue*> &Globals = NN->getGlobals(); |
| for (unsigned G = 0, e = Globals.size(); G != e; ++G) |
| if (Function *F = dyn_cast<Function>(Globals[G])) |
| ArgsRemainIncomplete.insert(F); |
| |
| markReachableFunctionsExternallyAccessible(NN, Visited); |
| } |
| } |
| } |
| |
| |
| // run - Calculate the top down data structure graphs for each function in the |
| // program. |
| // |
| bool TDDataStructures::run(Module &M) { |
| BUDataStructures &BU = getAnalysis<BUDataStructures>(); |
| GlobalsGraph = new DSGraph(BU.getGlobalsGraph()); |
| GlobalsGraph->setPrintAuxCalls(); |
| |
| // Figure out which functions must not mark their arguments complete because |
| // they are accessible outside this compilation unit. Currently, these |
| // arguments are functions which are reachable by global variables in the |
| // globals graph. |
| const DSGraph::ScalarMapTy &GGSM = GlobalsGraph->getScalarMap(); |
| hash_set<DSNode*> Visited; |
| for (DSGraph::ScalarMapTy::const_iterator I = GGSM.begin(), E = GGSM.end(); |
| I != E; ++I) |
| if (isa<GlobalValue>(I->first)) |
| markReachableFunctionsExternallyAccessible(I->second.getNode(), Visited); |
| |
| // Loop over unresolved call nodes. Any functions passed into (but not |
| // returned!?) from unresolvable call nodes may be invoked outside of the |
| // current module. |
| const std::vector<DSCallSite> &Calls = GlobalsGraph->getAuxFunctionCalls(); |
| for (unsigned i = 0, e = Calls.size(); i != e; ++i) { |
| const DSCallSite &CS = Calls[i]; |
| for (unsigned arg = 0, e = CS.getNumPtrArgs(); arg != e; ++arg) |
| markReachableFunctionsExternallyAccessible(CS.getPtrArg(arg).getNode(), |
| Visited); |
| } |
| Visited.clear(); |
| |
| // Functions without internal linkage also have unknown incoming arguments! |
| for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) |
| if (!I->isExternal() && !I->hasInternalLinkage()) |
| ArgsRemainIncomplete.insert(I); |
| |
| // We want to traverse the call graph in reverse post-order. To do this, we |
| // calculate a post-order traversal, then reverse it. |
| hash_set<DSGraph*> VisitedGraph; |
| std::vector<DSGraph*> PostOrder; |
| const BUDataStructures::ActualCalleesTy &ActualCallees = |
| getAnalysis<BUDataStructures>().getActualCallees(); |
| |
| // Calculate top-down from main... |
| if (Function *F = M.getMainFunction()) |
| ComputePostOrder(*F, VisitedGraph, PostOrder, ActualCallees); |
| |
| // Next calculate the graphs for each unreachable function... |
| for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) |
| ComputePostOrder(*I, VisitedGraph, PostOrder, ActualCallees); |
| |
| VisitedGraph.clear(); // Release memory! |
| |
| // Visit each of the graphs in reverse post-order now! |
| while (!PostOrder.empty()) { |
| inlineGraphIntoCallees(*PostOrder.back()); |
| PostOrder.pop_back(); |
| } |
| |
| ArgsRemainIncomplete.clear(); |
| return false; |
| } |
| |
| |
| DSGraph &TDDataStructures::getOrCreateDSGraph(Function &F) { |
| DSGraph *&G = DSInfo[&F]; |
| if (G == 0) { // Not created yet? Clone BU graph... |
| G = new DSGraph(getAnalysis<BUDataStructures>().getDSGraph(F)); |
| G->getAuxFunctionCalls().clear(); |
| G->setPrintAuxCalls(); |
| G->setGlobalsGraph(GlobalsGraph); |
| } |
| return *G; |
| } |
| |
| |
| void TDDataStructures::ComputePostOrder(Function &F,hash_set<DSGraph*> &Visited, |
| std::vector<DSGraph*> &PostOrder, |
| const BUDataStructures::ActualCalleesTy &ActualCallees) { |
| if (F.isExternal()) return; |
| DSGraph &G = getOrCreateDSGraph(F); |
| if (Visited.count(&G)) return; |
| Visited.insert(&G); |
| |
| // Recursively traverse all of the callee graphs. |
| const std::vector<DSCallSite> &FunctionCalls = G.getFunctionCalls(); |
| |
| for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i) { |
| Instruction *CallI = FunctionCalls[i].getCallSite().getInstruction(); |
| std::pair<BUDataStructures::ActualCalleesTy::const_iterator, |
| BUDataStructures::ActualCalleesTy::const_iterator> |
| IP = ActualCallees.equal_range(CallI); |
| |
| for (BUDataStructures::ActualCalleesTy::const_iterator I = IP.first; |
| I != IP.second; ++I) |
| ComputePostOrder(*I->second, Visited, PostOrder, ActualCallees); |
| } |
| |
| PostOrder.push_back(&G); |
| } |
| |
| |
| |
| |
| |
| // releaseMemory - If the pass pipeline is done with this pass, we can release |
| // our memory... here... |
| // |
| // FIXME: This should be releaseMemory and will work fine, except that LoadVN |
| // has no way to extend the lifetime of the pass, which screws up ds-aa. |
| // |
| void TDDataStructures::releaseMyMemory() { |
| for (hash_map<Function*, DSGraph*>::iterator I = DSInfo.begin(), |
| E = DSInfo.end(); I != E; ++I) { |
| I->second->getReturnNodes().erase(I->first); |
| if (I->second->getReturnNodes().empty()) |
| delete I->second; |
| } |
| |
| // Empty map so next time memory is released, data structures are not |
| // re-deleted. |
| DSInfo.clear(); |
| delete GlobalsGraph; |
| GlobalsGraph = 0; |
| } |
| |
| void TDDataStructures::inlineGraphIntoCallees(DSGraph &Graph) { |
| // Recompute the Incomplete markers and eliminate unreachable nodes. |
| Graph.removeTriviallyDeadNodes(); |
| Graph.maskIncompleteMarkers(); |
| |
| // If any of the functions has incomplete incoming arguments, don't mark any |
| // of them as complete. |
| bool HasIncompleteArgs = false; |
| const DSGraph::ReturnNodesTy &GraphReturnNodes = Graph.getReturnNodes(); |
| for (DSGraph::ReturnNodesTy::const_iterator I = GraphReturnNodes.begin(), |
| E = GraphReturnNodes.end(); I != E; ++I) |
| if (ArgsRemainIncomplete.count(I->first)) { |
| HasIncompleteArgs = true; |
| break; |
| } |
| |
| // Now fold in the necessary globals from the GlobalsGraph. A global G |
| // must be folded in if it exists in the current graph (i.e., is not dead) |
| // and it was not inlined from any of my callers. If it was inlined from |
| // a caller, it would have been fully consistent with the GlobalsGraph |
| // in the caller so folding in is not necessary. Otherwise, this node came |
| // solely from this function's BU graph and so has to be made consistent. |
| // |
| Graph.updateFromGlobalGraph(); |
| |
| // Recompute the Incomplete markers. Depends on whether args are complete |
| unsigned Flags |
| = HasIncompleteArgs ? DSGraph::MarkFormalArgs : DSGraph::IgnoreFormalArgs; |
| Graph.markIncompleteNodes(Flags | DSGraph::IgnoreGlobals); |
| |
| // Delete dead nodes. Treat globals that are unreachable as dead also. |
| Graph.removeDeadNodes(DSGraph::RemoveUnreachableGlobals); |
| |
| // We are done with computing the current TD Graph! Now move on to |
| // inlining the current graph into the graphs for its callees, if any. |
| // |
| const std::vector<DSCallSite> &FunctionCalls = Graph.getFunctionCalls(); |
| if (FunctionCalls.empty()) { |
| DEBUG(std::cerr << " [TD] No callees for: " << Graph.getFunctionNames() |
| << "\n"); |
| return; |
| } |
| |
| // Now that we have information about all of the callees, propagate the |
| // current graph into the callees. Clone only the reachable subgraph at |
| // each call-site, not the entire graph (even though the entire graph |
| // would be cloned only once, this should still be better on average). |
| // |
| DEBUG(std::cerr << " [TD] Inlining '" << Graph.getFunctionNames() <<"' into " |
| << FunctionCalls.size() << " call nodes.\n"); |
| |
| const BUDataStructures::ActualCalleesTy &ActualCallees = |
| getAnalysis<BUDataStructures>().getActualCallees(); |
| |
| // Loop over all the call sites and all the callees at each call site. |
| // Clone and merge the reachable subgraph from the call into callee's graph. |
| // |
| for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i) { |
| Instruction *CallI = FunctionCalls[i].getCallSite().getInstruction(); |
| // For each function in the invoked function list at this call site... |
| std::pair<BUDataStructures::ActualCalleesTy::const_iterator, |
| BUDataStructures::ActualCalleesTy::const_iterator> |
| IP = ActualCallees.equal_range(CallI); |
| |
| // Multiple callees may have the same graph, so try to inline and merge |
| // only once for each <callSite,calleeGraph> pair, not once for each |
| // <callSite,calleeFunction> pair; the latter will be correct but slower. |
| hash_set<DSGraph*> GraphsSeen; |
| |
| // Loop over each actual callee at this call site |
| for (BUDataStructures::ActualCalleesTy::const_iterator I = IP.first; |
| I != IP.second; ++I) { |
| DSGraph& CalleeGraph = getDSGraph(*I->second); |
| assert(&CalleeGraph != &Graph && "TD need not inline graph into self!"); |
| |
| // if this callee graph is already done at this site, skip this callee |
| if (GraphsSeen.find(&CalleeGraph) != GraphsSeen.end()) |
| continue; |
| GraphsSeen.insert(&CalleeGraph); |
| |
| // Get the root nodes for cloning the reachable subgraph into each callee: |
| // -- all global nodes that appear in both the caller and the callee |
| // -- return value at this call site, if any |
| // -- actual arguments passed at this call site |
| // -- callee node at this call site, if this is an indirect call (this may |
| // not be needed for merging, but allows us to create CS and therefore |
| // simplify the merging below). |
| hash_set<const DSNode*> RootNodeSet; |
| for (DSGraph::ScalarMapTy::const_iterator |
| SI = CalleeGraph.getScalarMap().begin(), |
| SE = CalleeGraph.getScalarMap().end(); SI != SE; ++SI) |
| if (GlobalValue* GV = dyn_cast<GlobalValue>(SI->first)) { |
| DSGraph::ScalarMapTy::const_iterator GI=Graph.getScalarMap().find(GV); |
| if (GI != Graph.getScalarMap().end()) |
| RootNodeSet.insert(GI->second.getNode()); |
| } |
| |
| if (const DSNode* RetNode = FunctionCalls[i].getRetVal().getNode()) |
| RootNodeSet.insert(RetNode); |
| |
| for (unsigned j=0, N=FunctionCalls[i].getNumPtrArgs(); j < N; ++j) |
| if (const DSNode* ArgTarget = FunctionCalls[i].getPtrArg(j).getNode()) |
| RootNodeSet.insert(ArgTarget); |
| |
| if (FunctionCalls[i].isIndirectCall()) |
| RootNodeSet.insert(FunctionCalls[i].getCalleeNode()); |
| |
| DEBUG(std::cerr << " [TD] Resolving arguments for callee graph '" |
| << CalleeGraph.getFunctionNames() |
| << "': " << I->second->getFunctionType()->getNumParams() |
| << " args\n at call site (DSCallSite*) 0x" |
| << &FunctionCalls[i] << "\n"); |
| |
| DSGraph::NodeMapTy NodeMapInCallee; // map from nodes to clones in callee |
| DSGraph::NodeMapTy CompletedMap; // unused map for nodes not to do |
| CalleeGraph.cloneReachableSubgraph(Graph, RootNodeSet, |
| NodeMapInCallee, CompletedMap, |
| DSGraph::StripModRefBits | |
| DSGraph::KeepAllocaBit); |
| |
| // Transform our call site info into the cloned version for CalleeGraph |
| DSCallSite CS(FunctionCalls[i], NodeMapInCallee); |
| |
| // Get the formal argument and return nodes for the called function |
| // and merge them with the cloned subgraph. Global nodes were merged |
| // already by cloneReachableSubgraph() above. |
| CalleeGraph.getCallSiteForArguments(*I->second).mergeWith(CS); |
| |
| ++NumTDInlines; |
| } |
| } |
| |
| DEBUG(std::cerr << " [TD] Done inlining into callees for: " |
| << Graph.getFunctionNames() << " [" << Graph.getGraphSize() << "+" |
| << Graph.getFunctionCalls().size() << "]\n"); |
| } |
| |
| } // End llvm namespace |