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https://github.com/c64scene-ar/llvm-6502.git
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7650b94c75
* Make the function pointer argument explicit for a call nodes * Eliminate unreachable global values * Merge call nodes that are identical git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2266 91177308-0d34-0410-b5e6-96231b3b80d8
251 lines
9.1 KiB
C++
251 lines
9.1 KiB
C++
//===- ComputeClosure.cpp - Implement interprocedural closing of graphs ---===//
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//
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// Compute the interprocedural closure of a data structure graph
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//
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//===----------------------------------------------------------------------===//
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// DEBUG_IP_CLOSURE - Define this to debug the act of linking up graphs
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//#define DEBUG_IP_CLOSURE 1
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#include "llvm/Analysis/DataStructure.h"
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#include "llvm/Function.h"
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#include "llvm/iOther.h"
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#include "Support/STLExtras.h"
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#include <algorithm>
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// Make all of the pointers that point to Val also point to N.
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//
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static void copyEdgesFromTo(PointerVal Val, DSNode *N) {
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unsigned ValIdx = Val.Index;
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unsigned NLinks = N->getNumLinks();
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const vector<PointerValSet*> &PVSsToUpdate(Val.Node->getReferrers());
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for (unsigned i = 0, e = PVSsToUpdate.size(); i != e; ++i) {
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// Loop over all of the pointers pointing to Val...
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PointerValSet &PVS = *PVSsToUpdate[i];
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for (unsigned j = 0, je = PVS.size(); j != je; ++j) {
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if (PVS[j].Node == Val.Node && PVS[j].Index >= ValIdx &&
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PVS[j].Index < ValIdx+NLinks)
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PVS.add(PointerVal(N, PVS[j].Index-ValIdx));
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}
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}
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}
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static void ResolveNodesTo(const PointerValSet &FromVals,
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const PointerValSet &ToVals) {
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// Only resolve the first pointer, although there many be many pointers here.
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// The problem is that the inlined function might return one of the arguments
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// to the function, and if so, extra values can be added to the arg or call
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// node that point to what the other one got resolved to. Since these will
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// be added to the end of the PVS pointed in, we just ignore them.
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//
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assert(!FromVals.empty() && "From should have at least a shadow node!");
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const PointerVal &FromPtr = FromVals[0];
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assert(FromPtr.Index == 0 &&
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"Resolved node return pointer should be index 0!");
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DSNode *N = FromPtr.Node;
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// Make everything that pointed to the shadow node also point to the values in
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// ToVals...
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//
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for (unsigned i = 0, e = ToVals.size(); i != e; ++i)
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copyEdgesFromTo(ToVals[i], N);
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// Make everything that pointed to the shadow node now also point to the
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// values it is equivalent to...
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const vector<PointerValSet*> &PVSToUpdate(N->getReferrers());
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for (unsigned i = 0, e = PVSToUpdate.size(); i != e; ++i)
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PVSToUpdate[i]->add(ToVals);
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}
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// ResolveNodeTo - The specified node is now known to point to the set of values
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// in ToVals, instead of the old shadow node subgraph that it was pointing to.
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//
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static void ResolveNodeTo(DSNode *Node, const PointerValSet &ToVals) {
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assert(Node->getNumLinks() == 1 && "Resolved node can only be a scalar!!");
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const PointerValSet &PVS = Node->getLink(0);
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ResolveNodesTo(PVS, ToVals);
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}
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// isResolvableCallNode - Return true if node is a call node and it is a call
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// node that we can inline...
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//
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static bool isResolvableCallNode(CallDSNode *CN) {
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// Only operate on call nodes with direct method calls
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Function *F = CN->getCall()->getCalledFunction();
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if (F == 0) return false;
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// Only work on call nodes with direct calls to methods with bodies.
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return !F->isExternal();
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}
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// computeClosure - Replace all of the resolvable call nodes with the contents
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// of their corresponding method data structure graph...
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//
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void FunctionDSGraph::computeClosure(const DataStructure &DS) {
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// Note that this cannot be a real vector because the keys will be changing
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// as nodes are eliminated!
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//
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typedef pair<vector<PointerValSet>, CallInst *> CallDescriptor;
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vector<pair<CallDescriptor, PointerValSet> > CallMap;
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unsigned NumInlines = 0;
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// Loop over the resolvable call nodes...
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vector<CallDSNode*>::iterator NI;
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NI = std::find_if(CallNodes.begin(), CallNodes.end(), isResolvableCallNode);
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while (NI != CallNodes.end()) {
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CallDSNode *CN = *NI;
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// FIXME: This should work based on the pointer val set of the first arg
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// link (which is the function to call)
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Function *F = CN->getCall()->getCalledFunction();
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if (NumInlines++ == 100) { // CUTE hack huh?
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cerr << "Infinite (?) recursion halted\n";
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return;
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}
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CallNodes.erase(NI); // Remove the call node from the graph
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unsigned CallNodeOffset = NI-CallNodes.begin();
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// Find out if we have already incorporated this node... if so, it will be
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// in the CallMap...
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//
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#if 0
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cerr << "\nSearching for: " << (void*)CN->getCall() << ": ";
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for (unsigned X = 0; X != CN->getArgs().size(); ++X) {
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cerr << " " << X << " is\n";
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CN->getArgs().first[X].print(cerr);
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}
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#endif
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const vector<PointerValSet> &Args = CN->getArgs();
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PointerValSet *CMI = 0;
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for (unsigned i = 0, e = CallMap.size(); i != e; ++i) {
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#if 0
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cerr << "Found: " << (void*)CallMap[i].first.second << ": ";
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for (unsigned X = 0; X != CallMap[i].first.first.size(); ++X) {
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cerr << " " << X << " is\n"; CallMap[i].first.first[X].print(cerr);
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}
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#endif
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// Look to see if the function call takes a superset of the values we are
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// providing as input
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//
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CallDescriptor &CD = CallMap[i].first;
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if (CD.second == CN->getCall() && CD.first.size() == Args.size()) {
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bool FoundMismatch = false;
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for (unsigned j = 0, je = Args.size(); j != je; ++j) {
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PointerValSet ArgSet = CD.first[j];
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if (ArgSet.add(Args[j])) {
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FoundMismatch = true; break;
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}
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}
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if (!FoundMismatch) { CMI = &CallMap[i].second; break; }
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}
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}
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// Hold the set of values that correspond to the incorporated methods
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// return set.
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//
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PointerValSet RetVals;
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if (CMI) {
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// We have already inlined an identical function call!
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RetVals = *CMI;
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} else {
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// Get the datastructure graph for the new method. Note that we are not
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// allowed to modify this graph because it will be the cached graph that
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// is returned by other users that want the local datastructure graph for
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// a method.
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//
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const FunctionDSGraph &NewFunction = DS.getDSGraph(F);
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// StartNode - The first node of the incorporated graph, last node of the
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// preexisting data structure graph...
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//
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unsigned StartAllocNode = AllocNodes.size();
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// Incorporate a copy of the called function graph into the current graph,
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// allowing us to do local transformations to local graph to link
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// arguments to call values, and call node to return value...
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//
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vector<PointerValSet> Args;
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RetVals = cloneFunctionIntoSelf(NewFunction, false, Args);
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CallMap.push_back(make_pair(CallDescriptor(CN->getArgs(), CN->getCall()),
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RetVals));
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// If the call node has arguments, process them now!
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assert(Args.size() == CN->getNumArgs()-1 &&
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"Call node doesn't match function?");
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for (unsigned i = 0, e = Args.size(); i != e; ++i) {
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// Now we make all of the nodes inside of the incorporated method
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// point to the real arguments values, not to the shadow nodes for the
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// argument.
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ResolveNodesTo(Args[i], CN->getArgValues(i+1));
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}
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// Loop through the nodes, deleting alloca nodes in the inlined function.
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// Since the memory has been released, we cannot access their pointer
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// fields (with defined results at least), so it is not possible to use
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// any pointers to the alloca. Drop them now, and remove the alloca's
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// since they are dead (we just removed all links to them).
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//
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for (unsigned i = StartAllocNode; i != AllocNodes.size(); ++i)
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if (AllocNodes[i]->isAllocaNode()) {
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AllocDSNode *NDS = AllocNodes[i];
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NDS->removeAllIncomingEdges(); // These edges are invalid now
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delete NDS; // Node is dead
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AllocNodes.erase(AllocNodes.begin()+i); // Remove slot in Nodes array
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--i; // Don't skip the next node
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}
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}
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// If the function returns a pointer value... Resolve values pointing to
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// the shadow nodes pointed to by CN to now point the values in RetVals...
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//
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if (CN->getNumLinks()) ResolveNodeTo(CN, RetVals);
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// Now the call node is completely destructable. Eliminate it now.
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delete CN;
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bool Changed = true;
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while (Changed) {
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// Eliminate shadow nodes that are not distinguishable from some other
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// node in the graph...
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//
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Changed = UnlinkUndistinguishableNodes();
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// Eliminate shadow nodes that are now extraneous due to linking...
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Changed |= RemoveUnreachableNodes();
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}
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//if (F == Func) return; // Only do one self inlining
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// Move on to the next call node...
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NI = std::find_if(CallNodes.begin(), CallNodes.end(), isResolvableCallNode);
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}
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// Drop references to globals...
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CallMap.clear();
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bool Changed = true;
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while (Changed) {
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// Eliminate shadow nodes that are not distinguishable from some other
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// node in the graph...
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//
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Changed = UnlinkUndistinguishableNodes();
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// Eliminate shadow nodes that are now extraneous due to linking...
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Changed |= RemoveUnreachableNodes();
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}
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}
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