- Make sure to only keep track of mappings that the TD pass may need in the

    future.  This prevents having spurious map entries to nodes that we really
    don't care about.  This allows us to reenable the DeadNodeElim, which was
    disabled.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@4260 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Analysis/DataStructure/TopDownClosure.cpp b/lib/Analysis/DataStructure/TopDownClosure.cpp
index 1fed1ab9a9c47664aebc13ad67f22e7d2cbca1af..7fdc33bb337ab52fc789ddcfdee8cffdefe71449 100644 (file)
--- a/lib/Analysis/DataStructure/TopDownClosure.cpp
+++ b/lib/Analysis/DataStructure/TopDownClosure.cpp
@@ -12,6 +12,7 @@
 #include "llvm/Module.h"
 #include "llvm/DerivedTypes.h"
 #include "Support/Statistic.h"
+#include <set>
 
 static RegisterAnalysis<TDDataStructures>
 Y("tddatastructure", "Top-down Data Structure Analysis Closure");
@@ -34,10 +35,23 @@ void TDDataStructures::releaseMemory() {
 // program.
 //
 bool TDDataStructures::run(Module &M) {
-  // Simply calculate the graphs for each function...
+  BUDataStructures &BU = getAnalysis<BUDataStructures>();
+
+  // Calculate the CallSitesForFunction mapping from the BU info...
+  for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
+    if (!I->isExternal())
+      if (const std::vector<DSCallSite> *CS = BU.getCallSites(*I))
+        for (unsigned i = 0, e = CS->size(); i != e; ++i)
+          if (Function *F = (*CS)[i].getResolvingCaller())
+            CallSitesForFunction[F].push_back(&(*CS)[i]);
+
+  // Next calculate the graphs for each function...
   for (Module::reverse_iterator I = M.rbegin(), E = M.rend(); I != E; ++I)
     if (!I->isExternal())
       calculateGraph(*I);
+
+  // Destroy the temporary mapping...
+  CallSitesForFunction.clear();
   return false;
 }
 
@@ -82,8 +96,37 @@ DSGraph &TDDataStructures::calculateGraph(Function &F) {
   std::map<const DSNode*, DSNode*> BUNodeMap;
   Graph = new DSGraph(BUGraph, BUNodeMap);
 
+  // We only need the BUMap entries for the nodes that are used in call sites.
+  // Calculate which nodes are needed.
+  std::set<const DSNode*> NeededNodes;
+  std::map<const Function*, std::vector<const DSCallSite*> >::iterator CSFFI
+    = CallSitesForFunction.find(&F);
+  if (CSFFI == CallSitesForFunction.end()) {
+    BUNodeMap.clear();  // No nodes are neccesary
+  } else {
+    std::vector<const DSCallSite*> &CSV = CSFFI->second;
+    for (unsigned i = 0, e = CSV.size(); i != e; ++i) {
+      NeededNodes.insert(CSV[i]->getRetVal().getNode());
+      for (unsigned j = 0, je = CSV[i]->getNumPtrArgs(); j != je; ++j)
+        NeededNodes.insert(CSV[i]->getPtrArg(j).getNode());
+    }
+  }
+
+  // Loop through te BUNodeMap, keeping only the nodes that are "Needed"
+  for (std::map<const DSNode*, DSNode*>::iterator I = BUNodeMap.begin();
+       I != BUNodeMap.end(); )
+    if (NeededNodes.count(I->first) && I->first)  // Keep needed nodes...
+      ++I;
+    else {
+      std::map<const DSNode*, DSNode*>::iterator J = I++;
+      BUNodeMap.erase(J);
+    }
+
+  NeededNodes.clear();  // We are done with this temporary data structure
+
   // Convert the mapping from a node-to-node map into a node-to-nodehandle map
-  BUMaps[&F].insert(BUNodeMap.begin(), BUNodeMap.end());
+  BUNodeMapTy &BUMap = BUMaps[&F];
+  BUMap.insert(BUNodeMap.begin(), BUNodeMap.end());
   BUNodeMap.clear();   // We are done with the temporary map.
 
   const std::vector<DSCallSite> *CallSitesP = BU.getCallSites(F);
@@ -140,12 +183,11 @@ DSGraph &TDDataStructures::calculateGraph(Function &F) {
   }
 
   // Recompute the Incomplete markers and eliminate unreachable nodes.
-#if 0
   Graph->maskIncompleteMarkers();
   Graph->markIncompleteNodes(/*markFormals*/ !F.hasInternalLinkage()
                              /*&& FIXME: NEED TO CHECK IF ALL CALLERS FOUND!*/);
   Graph->removeDeadNodes(/*KeepAllGlobals*/ false, /*KeepCalls*/ false);
-#endif
+
   DEBUG(std::cerr << "  [TD] Done inlining callers for: " << F.getName() << " ["
         << Graph->getGraphSize() << "+" << Graph->getFunctionCalls().size()
         << "]\n");