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https://github.com/c64scene-ar/llvm-6502.git
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6806f5614d
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@7492 91177308-0d34-0410-b5e6-96231b3b80d8
272 lines
11 KiB
C++
272 lines
11 KiB
C++
//===- TopDownClosure.cpp - Compute the top-down interprocedure closure ---===//
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//
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// This file implements the TDDataStructures class, which represents the
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// Top-down Interprocedural closure of the data structure graph over the
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// program. This is useful (but not strictly necessary?) for applications
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// like pointer analysis.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/DataStructure.h"
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#include "llvm/Module.h"
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#include "llvm/DerivedTypes.h"
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#include "Support/Debug.h"
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#include "Support/Statistic.h"
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#include "DSCallSiteIterator.h"
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namespace {
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RegisterAnalysis<TDDataStructures> // Register the pass
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Y("tddatastructure", "Top-down Data Structure Analysis");
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Statistic<> NumTDInlines("tddatastructures", "Number of graphs inlined");
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}
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/// FunctionHasCompleteArguments - This function returns true if it is safe not
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/// to mark arguments to the function complete.
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///
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/// FIXME: Need to check if all callers have been found, or rather if a
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/// funcpointer escapes!
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///
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static bool FunctionHasCompleteArguments(Function &F) {
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return F.hasInternalLinkage();
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}
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// run - Calculate the top down data structure graphs for each function in the
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// program.
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//
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bool TDDataStructures::run(Module &M) {
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BUDataStructures &BU = getAnalysis<BUDataStructures>();
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GlobalsGraph = new DSGraph(BU.getGlobalsGraph());
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// Figure out which functions must not mark their arguments complete because
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// they are accessible outside this compilation unit.
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for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
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if (!FunctionHasCompleteArguments(*I))
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ArgsRemainIncomplete.insert(I);
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// We want to traverse the call graph in reverse post-order. To do this, we
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// calculate a post-order traversal, then reverse it.
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hash_set<DSGraph*> VisitedGraph;
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std::vector<DSGraph*> PostOrder;
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const BUDataStructures::ActualCalleesTy &ActualCallees =
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getAnalysis<BUDataStructures>().getActualCallees();
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// Calculate top-down from main...
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if (Function *F = M.getMainFunction())
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ComputePostOrder(*F, VisitedGraph, PostOrder, ActualCallees);
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// Next calculate the graphs for each unreachable function...
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for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
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ComputePostOrder(*I, VisitedGraph, PostOrder, ActualCallees);
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VisitedGraph.clear(); // Release memory!
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// Visit each of the graphs in reverse post-order now!
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while (!PostOrder.empty()) {
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inlineGraphIntoCallees(*PostOrder.back());
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PostOrder.pop_back();
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}
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ArgsRemainIncomplete.clear();
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return false;
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}
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DSGraph &TDDataStructures::getOrCreateDSGraph(Function &F) {
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DSGraph *&G = DSInfo[&F];
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if (G == 0) { // Not created yet? Clone BU graph...
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G = new DSGraph(getAnalysis<BUDataStructures>().getDSGraph(F));
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G->getAuxFunctionCalls().clear();
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G->setPrintAuxCalls();
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G->setGlobalsGraph(GlobalsGraph);
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}
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return *G;
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}
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void TDDataStructures::ComputePostOrder(Function &F,hash_set<DSGraph*> &Visited,
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std::vector<DSGraph*> &PostOrder,
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const BUDataStructures::ActualCalleesTy &ActualCallees) {
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if (F.isExternal()) return;
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DSGraph &G = getOrCreateDSGraph(F);
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if (Visited.count(&G)) return;
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Visited.insert(&G);
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// Recursively traverse all of the callee graphs.
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const std::vector<DSCallSite> &FunctionCalls = G.getFunctionCalls();
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for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i) {
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std::pair<BUDataStructures::ActualCalleesTy::const_iterator,
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BUDataStructures::ActualCalleesTy::const_iterator>
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IP = ActualCallees.equal_range(&FunctionCalls[i].getCallInst());
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for (BUDataStructures::ActualCalleesTy::const_iterator I = IP.first;
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I != IP.second; ++I)
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ComputePostOrder(*I->second, Visited, PostOrder, ActualCallees);
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}
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PostOrder.push_back(&G);
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}
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// releaseMemory - If the pass pipeline is done with this pass, we can release
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// our memory... here...
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//
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// FIXME: This should be releaseMemory and will work fine, except that LoadVN
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// has no way to extend the lifetime of the pass, which screws up ds-aa.
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//
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void TDDataStructures::releaseMyMemory() {
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for (hash_map<Function*, DSGraph*>::iterator I = DSInfo.begin(),
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E = DSInfo.end(); I != E; ++I) {
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I->second->getReturnNodes().erase(I->first);
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if (I->second->getReturnNodes().empty())
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delete I->second;
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}
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// Empty map so next time memory is released, data structures are not
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// re-deleted.
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DSInfo.clear();
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delete GlobalsGraph;
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GlobalsGraph = 0;
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}
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void TDDataStructures::inlineGraphIntoCallees(DSGraph &Graph) {
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// Recompute the Incomplete markers and eliminate unreachable nodes.
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Graph.removeTriviallyDeadNodes();
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Graph.maskIncompleteMarkers();
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// If any of the functions has incomplete incoming arguments, don't mark any
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// of them as complete.
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bool HasIncompleteArgs = false;
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const DSGraph::ReturnNodesTy &GraphReturnNodes = Graph.getReturnNodes();
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for (DSGraph::ReturnNodesTy::const_iterator I = GraphReturnNodes.begin(),
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E = GraphReturnNodes.end(); I != E; ++I)
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if (ArgsRemainIncomplete.count(I->first)) {
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HasIncompleteArgs = true;
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break;
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}
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// Now fold in the necessary globals from the GlobalsGraph. A global G
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// must be folded in if it exists in the current graph (i.e., is not dead)
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// and it was not inlined from any of my callers. If it was inlined from
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// a caller, it would have been fully consistent with the GlobalsGraph
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// in the caller so folding in is not necessary. Otherwise, this node came
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// solely from this function's BU graph and so has to be made consistent.
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//
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Graph.updateFromGlobalGraph();
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// Recompute the Incomplete markers. Depends on whether args are complete
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unsigned Flags
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= HasIncompleteArgs ? DSGraph::MarkFormalArgs : DSGraph::IgnoreFormalArgs;
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Graph.markIncompleteNodes(Flags | DSGraph::IgnoreGlobals);
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// Delete dead nodes. Treat globals that are unreachable as dead also.
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Graph.removeDeadNodes(DSGraph::RemoveUnreachableGlobals);
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// We are done with computing the current TD Graph! Now move on to
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// inlining the current graph into the graphs for its callees, if any.
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//
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const std::vector<DSCallSite> &FunctionCalls = Graph.getFunctionCalls();
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if (FunctionCalls.empty()) {
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DEBUG(std::cerr << " [TD] No callees for: " << Graph.getFunctionNames()
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<< "\n");
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return;
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}
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// Now that we have information about all of the callees, propagate the
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// current graph into the callees. Clone only the reachable subgraph at
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// each call-site, not the entire graph (even though the entire graph
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// would be cloned only once, this should still be better on average).
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//
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DEBUG(std::cerr << " [TD] Inlining '" << Graph.getFunctionNames() <<"' into "
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<< FunctionCalls.size() << " call nodes.\n");
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const BUDataStructures::ActualCalleesTy &ActualCallees =
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getAnalysis<BUDataStructures>().getActualCallees();
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// Loop over all the call sites and all the callees at each call site.
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// Clone and merge the reachable subgraph from the call into callee's graph.
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//
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for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i) {
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// For each function in the invoked function list at this call site...
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std::pair<BUDataStructures::ActualCalleesTy::const_iterator,
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BUDataStructures::ActualCalleesTy::const_iterator>
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IP = ActualCallees.equal_range(&FunctionCalls[i].getCallInst());
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// Multiple callees may have the same graph, so try to inline and merge
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// only once for each <callSite,calleeGraph> pair, not once for each
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// <callSite,calleeFunction> pair; the latter will be correct but slower.
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hash_set<DSGraph*> GraphsSeen;
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// Loop over each actual callee at this call site
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for (BUDataStructures::ActualCalleesTy::const_iterator I = IP.first;
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I != IP.second; ++I) {
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DSGraph& CalleeGraph = getDSGraph(*I->second);
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assert(&CalleeGraph != &Graph && "TD need not inline graph into self!");
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// if this callee graph is already done at this site, skip this callee
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if (GraphsSeen.find(&CalleeGraph) != GraphsSeen.end())
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continue;
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GraphsSeen.insert(&CalleeGraph);
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// Get the root nodes for cloning the reachable subgraph into each callee:
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// -- all global nodes that appear in both the caller and the callee
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// -- return value at this call site, if any
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// -- actual arguments passed at this call site
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// -- callee node at this call site, if this is an indirect call (this may
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// not be needed for merging, but allows us to create CS and therefore
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// simplify the merging below).
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hash_set<const DSNode*> RootNodeSet;
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for (DSGraph::ScalarMapTy::const_iterator
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SI = CalleeGraph.getScalarMap().begin(),
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SE = CalleeGraph.getScalarMap().end(); SI != SE; ++SI)
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if (GlobalValue* GV = dyn_cast<GlobalValue>(SI->first)) {
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DSGraph::ScalarMapTy::const_iterator GI=Graph.getScalarMap().find(GV);
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if (GI != Graph.getScalarMap().end())
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RootNodeSet.insert(GI->second.getNode());
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}
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if (const DSNode* RetNode = FunctionCalls[i].getRetVal().getNode())
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RootNodeSet.insert(RetNode);
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for (unsigned j=0, N=FunctionCalls[i].getNumPtrArgs(); j < N; ++j)
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if (const DSNode* ArgTarget = FunctionCalls[i].getPtrArg(j).getNode())
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RootNodeSet.insert(ArgTarget);
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if (FunctionCalls[i].isIndirectCall())
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RootNodeSet.insert(FunctionCalls[i].getCalleeNode());
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DEBUG(std::cerr << " [TD] Resolving arguments for callee graph '"
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<< CalleeGraph.getFunctionNames()
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<< "': " << I->second->getFunctionType()->getNumParams()
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<< " args\n at call site (DSCallSite*) 0x"
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<< &FunctionCalls[i] << "\n");
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DSGraph::NodeMapTy NodeMapInCallee; // map from nodes to clones in callee
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DSGraph::NodeMapTy CompletedMap; // unused map for nodes not to do
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CalleeGraph.cloneReachableSubgraph(Graph, RootNodeSet,
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NodeMapInCallee, CompletedMap,
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DSGraph::StripModRefBits |
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DSGraph::KeepAllocaBit);
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// Transform our call site info into the cloned version for CalleeGraph
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DSCallSite CS(FunctionCalls[i], NodeMapInCallee);
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// Get the formal argument and return nodes for the called function
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// and merge them with the cloned subgraph. Global nodes were merged
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// already by cloneReachableSubgraph() above.
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CalleeGraph.getCallSiteForArguments(*I->second).mergeWith(CS);
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++NumTDInlines;
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}
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}
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DEBUG(std::cerr << " [TD] Done inlining into callees for: "
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<< Graph.getFunctionNames() << " [" << Graph.getGraphSize() << "+"
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<< Graph.getFunctionCalls().size() << "]\n");
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}
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