示例#1
0
/**
 * A runtime guard block may have monitor stores and privarg stores along with the guard
 * it self. This method will rearrange these stores and split the block, managing any
 * uncommoning necessary for eventual block order.
 *
 * The provided block will become the privarg block, containing any privarg stores and additonal
 * temps for uncommoning. It must be evaluated first. The returned block will contain monitor
 * stores and the guard. If no split is required, the provided block will be returned.
 *
 * @param comp Compilation object
 * @param block Block to manipulate
 * @param cfg Current CFG
 * @return The block containing the guard.
 */
static TR::Block* splitRuntimeGuardBlock(TR::Compilation *comp, TR::Block* block, TR::CFG *cfg)
   {
   TR::NodeChecklist checklist(comp);
   TR::TreeTop *start = block->getFirstRealTreeTop();
   TR::TreeTop *guard = block->getLastRealTreeTop();
   TR::TreeTop *firstPrivArg = NULL;
   TR::TreeTop *firstMonitor = NULL;

   // Manage the unexpected case that monitors and priv args are reversed
   bool privThenMonitor = false;

   TR_ASSERT(isMergeableGuard(guard->getNode()), "last node must be guard %p", guard->getNode());

   // Search for privarg and monitor stores
   // Only commoned nodes under the guard are required to be anchored, due to the guard being
   // evaluted before the monitor stores later on
   bool anchoredTemps = false;
   for (TR::TreeTop *tt = start; tt && tt->getNode()->getOpCodeValue() != TR::BBEnd; tt = tt->getNextTreeTop())
      {
      TR::Node * node = tt->getNode();

      if (node->getOpCode().hasSymbolReference() && node->getSymbol()->holdsMonitoredObject())
         firstMonitor = firstMonitor == NULL ? tt : firstMonitor;
      else if (node->chkIsPrivatizedInlinerArg())
         {
         if (firstPrivArg == NULL)
            {
            firstPrivArg = tt;
            privThenMonitor = (firstMonitor == NULL);
            }
         }
      else if (isMergeableGuard(node))
         anchoredTemps |= anchorCommonNodes(comp, node, start, checklist);
      else
         TR_ASSERT(0, "Node other than monitor or privarg store %p before runtime guard", node);
      }

   // If there are monitors then privargs, they must be swapped around, such that all privargs are
   // evaluated first
   if (firstPrivArg && firstMonitor && !privThenMonitor)
      {
      TR::TreeTop *monitorEnd = firstPrivArg->getPrevTreeTop();
      firstMonitor->getPrevTreeTop()->join(firstPrivArg);
      guard->getPrevTreeTop()->join(firstMonitor);
      monitorEnd->join(guard);
      }

   // If there were temps created or privargs in the block, perform a split
   TR::TreeTop *split = NULL;
   if (firstPrivArg)
      split = firstMonitor ? firstMonitor : guard;
   else if (anchoredTemps)
      split = start;

   if (split)
      return block->split(split, cfg, true /* fixupCommoning */, false /* copyExceptionSuccessors */);
   return block;
   }
示例#2
0
// Add an async check into a block - MUST be at block entry
//
void TR_AsyncCheckInsertion::insertAsyncCheck(TR::Block *block, TR::Compilation *comp, const char *counterPrefix)
   {
   TR::TreeTop *lastTree = block->getLastRealTreeTop();
   TR::TreeTop *asyncTree =
      TR::TreeTop::create(comp,
         TR::Node::createWithSymRef(lastTree->getNode(), TR::asynccheck, 0,
            comp->getSymRefTab()->findOrCreateAsyncCheckSymbolRef(comp->getMethodSymbol())));


   if (lastTree->getNode()->getOpCode().isReturn())
      {
      TR::TreeTop *prevTree = lastTree->getPrevTreeTop();
      prevTree->join(asyncTree);
      asyncTree->join(lastTree);
      }
   else
      {
      TR::TreeTop *nextTree = block->getEntry()->getNextTreeTop();
      block->getEntry()->join(asyncTree);
      asyncTree->join(nextTree);
      }

   const char * const name = TR::DebugCounter::debugCounterName(comp,
      "asynccheck.insert/%s/(%s)/%s/block_%d",
      counterPrefix,
      comp->signature(),
      comp->getHotnessName(),
      block->getNumber());
   TR::DebugCounter::prependDebugCounter(comp, name, asyncTree->getNextTreeTop());
   }
示例#3
0
void TR::ILValidator::checkSoundness(TR::TreeTop *start, TR::TreeTop *stop)
   {
   soundnessRule(start, start != NULL, "Start tree must exist");
   soundnessRule(stop, !stop || stop->getNode() != NULL, "Stop tree must have a node");

   TR::NodeChecklist treetopNodes(comp()), ancestorNodes(comp()), visitedNodes(comp());

   // Can't use iterators here, because those presuppose the IL is sound.  Walk trees the old-fashioned way.
   //
   for (TR::TreeTop *currentTree = start; currentTree != stop; currentTree = currentTree->getNextTreeTop())
      {
      soundnessRule(currentTree, currentTree->getNode() != NULL, "Tree must have a node");
      soundnessRule(currentTree, !treetopNodes.contains(currentTree->getNode()), "Treetop node n%dn encountered twice", currentTree->getNode()->getGlobalIndex());

      treetopNodes.add(currentTree->getNode());

      TR::TreeTop *next = currentTree->getNextTreeTop();
      if (next)
         {
         soundnessRule(currentTree, next->getNode() != NULL, "Tree after n%dn must have a node", currentTree->getNode()->getGlobalIndex());
         soundnessRule(currentTree, next->getPrevTreeTop() == currentTree, "Doubly-linked treetop list must be consistent: n%dn->n%dn<-n%dn", currentTree->getNode()->getGlobalIndex(), next->getNode()->getGlobalIndex(), next->getPrevTreeTop()->getNode()->getGlobalIndex());
         }
      else
         {
         soundnessRule(currentTree, stop == NULL, "Reached the end of the trees after n%dn without encountering the stop tree n%dn", currentTree->getNode()->getGlobalIndex(), stop? stop->getNode()->getGlobalIndex() : 0);
         checkNodeSoundness(currentTree, currentTree->getNode(), ancestorNodes, visitedNodes);
         }
      }
   }
示例#4
0
void
TR_ExpressionsSimplification::transformNode(TR::Node *srcNode, TR::Block *dstBlock)
   {
   TR::TreeTop *lastTree = dstBlock->getLastRealTreeTop();
   TR::TreeTop *prevTree = lastTree->getPrevTreeTop();
   TR::TreeTop *srcNodeTT = TR::TreeTop::create(comp(), srcNode);

   if (trace())
      comp()->getDebug()->print(comp()->getOutFile(),srcNode,0,true);

   if (lastTree->getNode()->getOpCode().isBranch() ||
       (lastTree->getNode()->getOpCode().isJumpWithMultipleTargets() && lastTree->getNode()->getOpCode().hasBranchChildren()))
      {
      srcNodeTT->join(lastTree);
      prevTree->join(srcNodeTT);
      }
   /*
   else if (dstBlock->getEntry()->getNode()->getOpCodeValue() == TR::BBStart)
      {
      srcNodeTT->join(dstBlock->getExit());
      dstBlock->getEntry()->join(srcNodeTT);
      }
   */
   else
      {
      srcNodeTT->join(dstBlock->getExit());
      lastTree->join(srcNodeTT);
      }
   return;
   }
示例#5
0
void TR_Latestness::analyzeTreeTopsInBlockStructure(TR_BlockStructure *blockStructure)
   {
   TR::Block *block = blockStructure->getBlock();
   TR::TreeTop *currentTree = block->getExit();
   TR::TreeTop *entryTree = block->getEntry();
   /////copyFromInto(_regularInfo, _outSetInfo[blockStructure->getNumber()]);
   bool notSeenTreeWithChecks = true;
   _containsExceptionTreeTop = false;

   while (!(currentTree == entryTree))
      {
      if (notSeenTreeWithChecks)
         {
         bool currentTreeHasChecks = treeHasChecks(currentTree);
         if (currentTreeHasChecks)
            {
            notSeenTreeWithChecks = false;
            _containsExceptionTreeTop = true;
            /////compose(_regularInfo, _exceptionInfo);
            /////compose(_outSetInfo[blockStructure->getNumber()], _exceptionInfo);
            }
         }
      else
         break;

      if (!(currentTree == entryTree))
         currentTree = currentTree->getPrevTreeTop();
      }

   }
示例#6
0
void TR::SoundnessRule::validate(TR::ResolvedMethodSymbol *methodSymbol)
   {
   TR::TreeTop *start = methodSymbol->getFirstTreeTop();
   TR::TreeTop *stop = methodSymbol->getLastTreeTop();
   checkSoundnessCondition(start, start != NULL, "Start tree must exist");
   checkSoundnessCondition(stop, !stop || stop->getNode() != NULL,
                           "Stop tree must have a node");

   TR::NodeChecklist treetopNodes(comp()), ancestorNodes(comp()), visitedNodes(comp());

   /* NOTE: Can't use iterators here, because iterators presuppose that the IL is sound. */
   for (TR::TreeTop *currentTree = start; currentTree != stop;
        currentTree = currentTree->getNextTreeTop())
      {
      checkSoundnessCondition(currentTree, currentTree->getNode() != NULL,
                              "Tree must have a node");
      checkSoundnessCondition(currentTree, !treetopNodes.contains(currentTree->getNode()),
                              "Treetop node n%dn encountered twice",
                              currentTree->getNode()->getGlobalIndex());

      treetopNodes.add(currentTree->getNode());

      TR::TreeTop *next = currentTree->getNextTreeTop();
      if (next)
         {
         checkSoundnessCondition(currentTree, next->getNode() != NULL,
                                 "Tree after n%dn must have a node",
                                 currentTree->getNode()->getGlobalIndex());
         checkSoundnessCondition(currentTree, next->getPrevTreeTop() == currentTree,
                                 "Doubly-linked treetop list must be consistent: n%dn->n%dn<-n%dn",
                                 currentTree->getNode()->getGlobalIndex(),
                                 next->getNode()->getGlobalIndex(),
                                 next->getPrevTreeTop()->getNode()->getGlobalIndex());
         }
      else
         {
         checkSoundnessCondition(currentTree, stop == NULL,
                                 "Reached the end of the trees after n%dn without encountering the stop tree n%dn",
                                 currentTree->getNode()->getGlobalIndex(),
                                 stop? stop->getNode()->getGlobalIndex() : 0);
         checkNodeSoundness(currentTree, currentTree->getNode(),
                            ancestorNodes, visitedNodes);
         }
      }
   }
示例#7
0
inline TR::TreeTop *
OMR::TreeTop::getPrevRealTreeTop()
   {
   TR::TreeTop *treeTop;
   for (treeTop = self()->getPrevTreeTop();
        treeTop && treeTop->getNode()->getOpCode().isExceptionRangeFence();
        treeTop = treeTop->getPrevTreeTop())
      {}
   return treeTop;
   }
示例#8
0
inline TR::Block *
OMR::TreeTop::getEnclosingBlock( bool forward)
   {
   TR::TreeTop * tt = self();
   if (forward)
      while (tt->getNode()->getOpCodeValue() != TR::BBEnd)
         {
         tt = tt->getNextTreeTop();
         //TR_ASSERT(tt && tt->getNode(), "either tt or node on a tt null here, we will segfault");
         }
   else
      while (tt->getNode()->getOpCodeValue() != TR::BBStart)
         {
         tt = tt->getPrevTreeTop();
         //TR_ASSERT(tt && tt->getNode(), "either tt or node on a tt null here, we will segfault");
         }
   return tt->getNode()->getBlock();
   }
示例#9
0
bool TR_LocalLiveRangeReduction::moveTreeBefore(TR_TreeRefInfo *treeToMove,TR_TreeRefInfo *anchor,int32_t passNumber)
   {
   TR::TreeTop *treeToMoveTT = treeToMove->getTreeTop();
   TR::TreeTop *anchorTT = anchor->getTreeTop();
   if (treeToMoveTT->getNextRealTreeTop() == anchorTT)
      {
      addDepPair(treeToMove, anchor);
      return false;
      }

   if (!performTransformation(comp(), "%sPass %d: moving tree [%p] before Tree %p\n", OPT_DETAILS, passNumber, treeToMoveTT->getNode(),anchorTT->getNode()))
      return false;

   //   printf("Moving [%p] before Tree %p\n",  treeToMoveTT->getNode(),anchorTT->getNode());


   //changing location in block
   TR::TreeTop *origPrevTree = treeToMoveTT->getPrevTreeTop();
   TR::TreeTop *origNextTree = treeToMoveTT->getNextTreeTop();
   origPrevTree->setNextTreeTop(origNextTree);
   origNextTree->setPrevTreeTop(origPrevTree);
   TR::TreeTop *prevTree = anchorTT->getPrevTreeTop();
   anchorTT->setPrevTreeTop(treeToMoveTT);
   treeToMoveTT->setNextTreeTop(anchorTT);
   treeToMoveTT->setPrevTreeTop(prevTree);
   prevTree->setNextTreeTop(treeToMoveTT);

   //UPDATE REFINFO
   //find locations of treeTops in TreeTopsRefInfo array
   //startIndex points to the currentTree that has moved
   //endIndex points to the treeTop after which we moved the tree (nextTree)

   int32_t startIndex = getIndexInArray(treeToMove);
   int32_t endIndex = getIndexInArray(anchor)-1;
   int32_t i=0;
   for ( i = startIndex+1; i<= endIndex ; i++)
      {
      TR_TreeRefInfo *currentTreeRefInfo = _treesRefInfoArray[i];
      List<TR::Node> *firstList = currentTreeRefInfo->getFirstRefNodesList();
      List<TR::Node> *midList = currentTreeRefInfo->getMidRefNodesList();
      List<TR::Node> *lastList = currentTreeRefInfo->getLastRefNodesList();
      List<TR::Node> *M_firstList = treeToMove->getFirstRefNodesList();
      List<TR::Node> *M_midList = treeToMove->getMidRefNodesList();
      List<TR::Node> *M_lastList = treeToMove->getLastRefNodesList();

      if (trace())
    	 {
    	 traceMsg(comp(),"Before move:\n");
    	 printRefInfo(treeToMove);
    	 printRefInfo(currentTreeRefInfo);
    	 }

      updateRefInfo(treeToMove->getTreeTop()->getNode(), currentTreeRefInfo, treeToMove , false);
      treeToMove->resetSyms();
      currentTreeRefInfo->resetSyms();
      populatePotentialDeps(currentTreeRefInfo,currentTreeRefInfo->getTreeTop()->getNode());
      populatePotentialDeps(treeToMove,treeToMove->getTreeTop()->getNode());

      if (trace())
    	 {
    	 traceMsg(comp(),"After move:\n");
    	 printRefInfo(treeToMove);
    	 printRefInfo(currentTreeRefInfo);
    	 traceMsg(comp(),"------------------------\n");
    	 }
      }

   TR_TreeRefInfo *temp = _treesRefInfoArray[startIndex];
   for (i = startIndex; i< endIndex ; i++)
      {
      _treesRefInfoArray[i] = _treesRefInfoArray[i+1];
      }

   _treesRefInfoArray[endIndex]=temp;

#if defined(DEBUG) || defined(PROD_WITH_ASSUMES)
   if (!(comp()->getOption(TR_EnableParanoidOptCheck) || debug("paranoidOptCheck")))
      return true;

   //verifier
   {
   TR::StackMemoryRegion stackMemoryRegion(*trMemory());

   vcount_t visitCount = comp()->getVisitCount();
   int32_t maxRefCount = 0;
   TR::TreeTop *tt;
   TR_TreeRefInfo **treesRefInfoArrayTemp = (TR_TreeRefInfo**)trMemory()->allocateStackMemory(_numTreeTops*sizeof(TR_TreeRefInfo*));
   memset(treesRefInfoArrayTemp, 0, _numTreeTops*sizeof(TR_TreeRefInfo*));
   TR_TreeRefInfo *treeRefInfoTemp;


   //collect info
   for ( int32_t i  = 0; i<_numTreeTops-1; i++)
      {
      tt =_treesRefInfoArray[i]->getTreeTop();
      treeRefInfoTemp = new (trStackMemory()) TR_TreeRefInfo(tt, trMemory());
      collectRefInfo(treeRefInfoTemp, tt->getNode(),visitCount,&maxRefCount);
      treesRefInfoArrayTemp[i] = treeRefInfoTemp;
      }

   comp()->setVisitCount(visitCount+maxRefCount);

   for ( int32_t i  = 0; i<_numTreeTops-1; i++)
      {
      if (!verifyRefInfo(treesRefInfoArrayTemp[i]->getFirstRefNodesList(),_treesRefInfoArray[i]->getFirstRefNodesList()))
    	 {
    	 printOnVerifyError(_treesRefInfoArray[i],treesRefInfoArrayTemp[i]);
    	 TR_ASSERT(0,"fail to verify firstRefNodesList for %p\n",_treesRefInfoArray[i]->getTreeTop()->getNode());
    	 }

      if (!verifyRefInfo(treesRefInfoArrayTemp[i]->getMidRefNodesList(),_treesRefInfoArray[i]->getMidRefNodesList()))
    	 {
    	 printOnVerifyError(_treesRefInfoArray[i],treesRefInfoArrayTemp[i]);
    	 TR_ASSERT(0,"fail to verify midRefNodesList for %p\n",_treesRefInfoArray[i]->getTreeTop()->getNode());
    	 }

      if (!verifyRefInfo(treesRefInfoArrayTemp[i]->getLastRefNodesList(),_treesRefInfoArray[i]->getLastRefNodesList()))
    	 {
    	 printOnVerifyError(_treesRefInfoArray[i],treesRefInfoArrayTemp[i]);
    	 TR_ASSERT(0,"fail to verify lastRefNodesList for %p\n",_treesRefInfoArray[i]->getTreeTop()->getNode());
    	 }


       }
   } // scope of the stack memory region

#endif
   return true;
   }
示例#10
0
TR::TreeTop *
OMR::Simplifier::simplifyExtendedBlock(TR::TreeTop * treeTop)
   {
   TR::Block * block = 0;

   _containingStructure = NULL;
   _blockRemoved = false;

   for (; treeTop; treeTop = treeTop->getNextTreeTop())
      {
      TR::Node * node = treeTop->getNode();
      TR_ASSERT(node->getOpCodeValue() == TR::BBStart, "Simplification, expected BBStart treetop");

      TR::Block * b = node->getBlock();
      if (block && !b->isExtensionOfPreviousBlock())
         break;

      if (b->isOSRCodeBlock() || b->isOSRCatchBlock())
         {
         b->setHasBeenVisited();
         treeTop = b->getExit();
         continue;
         }

#ifdef DEBUG
      if (block != b)
         b->setHasBeenVisited();
#endif

      if (!block && _reassociate &&
          comp()->getFlowGraph()->getStructure() != NULL         // [99391] getStructureOf() only valid if structure isn't invalidated
         )
         { // b is first block in the extended block
         TR_BlockStructure *blockStructure = b->getStructureOf();

         if(blockStructure)
            {
            TR_Structure *parent = blockStructure->getParent();
            while (parent)
               {
               TR_RegionStructure *region = parent->asRegion();
               if (region->isNaturalLoop() /* || region->containsInternalCycles() */)
                  {
                  _containingStructure = region;
                  break;
                  }
               parent = parent->getParent();
               }
            }
         }

      block = b;

      if (trace())
         traceMsg(comp(), "simplifying block_%d\n", block->getNumber());

      _performLowerTreeSimplifier=NULL;
      _performLowerTreeNode=NULL;
      simplify(block);

      if(_performLowerTreeSimplifier)
         {
         _performLowerTreeNode = postWalkLowerTreeSimplifier(_performLowerTreeSimplifier, _performLowerTreeNode, block, (TR::Simplifier *) this);
         _performLowerTreeSimplifier->setNode(_performLowerTreeNode);
         }

      // If the block itself was removed from the CFG during simplification, find
      // the next 'legitimate' block to be simplified
      //
      //if (comp()->getFlowGraph()->getRemovedNodes().find(block))
        if(block->nodeIsRemoved())
         {
         TR::TreeTop * tt = findNextLegalTreeTop(comp(), block);
         // in certain cases the removed block might be the last one we haven't
         // visited and therefore we won't be able to find a treetop to continue
         // in such cases we exit the loop
         //
         treeTop = tt ? tt->getPrevTreeTop() : 0;
         if (!treeTop)
            break;
         }
      else
         {
         treeTop = block->getExit();
         }
      }

   // now remove any unreachable blocks
   //
   if (_blockRemoved)
      {
      // if the next block to be processed has been removed,
      // find the next valid block to process
      //
      if (treeTop)
         {
         TR::Block *b = treeTop->getNode()->getBlock();
         //if (comp()->getFlowGraph()->getRemovedNodes().find(b))
           if(b->nodeIsRemoved())
            treeTop = findNextLegalTreeTop(comp(), b);
         }
      }

   return treeTop;
   }
示例#11
0
int32_t TR::DeadTreesElimination::process(TR::TreeTop *startTree, TR::TreeTop *endTree)
   {
   TR::StackMemoryRegion stackRegion(*comp()->trMemory());
   LongestPathMap longestPaths(std::less<TR::Node*>(), stackRegion);

   typedef TR::typed_allocator<CRAnchor, TR::Region&> CRAnchorAlloc;
   typedef TR::forward_list<CRAnchor, CRAnchorAlloc> CRAnchorList;
   CRAnchorList anchors(stackRegion);

   vcount_t visitCount = comp()->incOrResetVisitCount();
   TR::TreeTop *treeTop;
   for (treeTop = startTree; (treeTop != endTree); treeTop = treeTop->getNextTreeTop())
      treeTop->getNode()->initializeFutureUseCounts(visitCount);

   TR::Block *block = NULL;
   bool delayedRegStoresBeforeThisPass = _delayedRegStores;

   // Update visitCount as they are used in this optimization and need to be
   visitCount = comp()->incOrResetVisitCount();
   for (TR::TreeTopIterator iter(startTree, comp()); iter != endTree; ++iter)
      {
      TR::Node *node = iter.currentTree()->getNode();

      if (node->getOpCodeValue() == TR::BBStart)
         {
         block = node->getBlock();
         if (!block->isExtensionOfPreviousBlock())
            longestPaths.clear();
         }

      int vcountLimit = MAX_VCOUNT - 3;
      if (comp()->getVisitCount() > vcountLimit)
         {
         dumpOptDetails(comp(),
            "%sVisit count %d exceeds limit %d; stopping\n",
            optDetailString(), comp()->getVisitCount(), vcountLimit);
         return 0;
         }

      // correct at all intermediate stages
      //
      if ((node->getOpCodeValue() != TR::treetop) &&
          (!node->getOpCode().isAnchor() || (node->getFirstChild()->getReferenceCount() != 1)) &&
          (!node->getOpCode().isStoreReg() || (node->getFirstChild()->getReferenceCount() != 1)) &&
          (delayedRegStoresBeforeThisPass ||
           (iter.currentTree() == block->getLastRealTreeTop()) ||
           !node->getOpCode().isStoreReg() ||
           (node->getVisitCount() == visitCount)))
         {
         if (node->getOpCode().isAnchor() && node->getFirstChild()->getOpCode().isLoadIndirect())
            anchors.push_front(CRAnchor(iter.currentTree(), block));

         TR::TransformUtil::recursivelySetNodeVisitCount(node, visitCount);
         continue;
         }

      if (node->getOpCode().isStoreReg())
         _delayedRegStores = true;

      TR::Node *child = node->getFirstChild();
      if (child->getOpCodeValue() == TR::PassThrough)
         {
         TR::Node *newChild = child->getFirstChild();
         node->setAndIncChild(0, newChild);
         newChild->incFutureUseCount();
         if (child->getReferenceCount() <= 1)
            optimizer()->prepareForNodeRemoval(child);
         child->recursivelyDecReferenceCount();
         recursivelyDecFutureUseCount(child);
         child = newChild;
         }

      bool treeTopCanBeEliminated = false;

      // If the treetop child has been seen before then it must be anchored
      // somewhere above already; so we don't need the treetop to be anchoring
      // this node (as the computation is already done at the first reference to
      // the node).
      //

      if (visitCount == child->getVisitCount())
         {
         treeTopCanBeEliminated = true;
         }
      else
         {
         TR::ILOpCode &childOpCode = child->getOpCode();
         TR::ILOpCodes opCodeValue = childOpCode.getOpCodeValue();
         bool seenConditionalBranch = false;

         bool callWithNoSideEffects = child->getOpCode().isCall() &&
              child->getSymbolReference()->getSymbol()->isResolvedMethod() &&
              child->getSymbolReference()->getSymbol()->castToResolvedMethodSymbol()->isSideEffectFree();

         if (callWithNoSideEffects)
            {
            treeTopCanBeEliminated = true;
            }
         else if (!((childOpCode.isCall() && !callWithNoSideEffects) ||
               childOpCode.isStore() ||
               ((opCodeValue == TR::New ||
                 opCodeValue == TR::anewarray ||
                 opCodeValue == TR::newarray) &&
                 child->getReferenceCount() > 1) ||
                 opCodeValue == TR::multianewarray ||
                 opCodeValue == TR::MergeNew ||
               opCodeValue == TR::checkcast ||
               opCodeValue == TR::Prefetch ||
               opCodeValue == TR::iu2l ||
               ((childOpCode.isDiv() ||
                 childOpCode.isRem()) &&
                 child->getNumChildren() == 3)))
            {
            // Perform the rather complex check to see whether its safe
            // to disconnect the child node from the treetop
            //
            bool safeToReplaceNode = false;
            if (child->getReferenceCount() == 1)
               {
               safeToReplaceNode = true;
#ifdef J9_PROJECT_SPECIFIC
               if (child->getOpCode().isPackedExponentiation())
                  {
                  // pdexp has a possible message side effect in truncating or no significant digits left cases
                  safeToReplaceNode = false;
                  }
#endif
               if (opCodeValue == TR::loadaddr)
                  treeTopCanBeEliminated = true;
               }
            else if (!_cannotBeEliminated)
               {
               safeToReplaceNode = isSafeToReplaceNode(
                  child,
                  iter.currentTree(),
                  &seenConditionalBranch,
                  visitCount,
                  comp(),
                  &_targetTrees,
                  _cannotBeEliminated,
                  longestPaths);
               }

            if (safeToReplaceNode)
               {
               if (childOpCode.hasSymbolReference())
                  {
                  TR::SymbolReference *symRef = child->getSymbolReference();

                  if (symRef->getSymbol()->isAuto() || symRef->getSymbol()->isParm())
                     treeTopCanBeEliminated = true;
                  else
                     {
                     if (childOpCode.isLoad() ||
                         (opCodeValue == TR::loadaddr) ||
                         (opCodeValue == TR::instanceof) ||
                         (((opCodeValue == TR::New)  ||
                            (opCodeValue == TR::anewarray ||
                              opCodeValue == TR::newarray)) &&
                          ///child->getFirstChild()->isNonNegative()))
                           child->markedAllocationCanBeRemoved()))
                       //        opCodeValue == TR::multianewarray ||
                       //        opCodeValue == TR::MergeNew)
                        treeTopCanBeEliminated = true;
                     }
                  }
               else
                  treeTopCanBeEliminated = true;
               }
            }

         // Fix for the case when a float to non-float conversion node swings
         // down past a branch on IA32; this would cause a FP value to be commoned
         // across a branch where there was none originally; this causes pblms
         // as a value is left on the stack.
         //
         if (treeTopCanBeEliminated &&
             seenConditionalBranch)
            {
            if (!cg()->getSupportsJavaFloatSemantics())
               {
               if (child->getOpCode().isConversion() ||
                   child->getOpCode().isBooleanCompare())
                 {
                 if (child->getFirstChild()->getOpCode().isFloatingPoint() &&
                     !child->getOpCode().isFloatingPoint())
                     treeTopCanBeEliminated = false;
                 }
               }
            }

         if (treeTopCanBeEliminated)
            {
            TR::NodeChecklist visited(comp());
            bool containsFloatingPoint = false;
            for (int32_t i = 0; i < child->getNumChildren(); ++i)
               {
               // Anchor nodes with reference count > 1
               //
               bool highGlobalIndex = false;
               if (fixUpTree(child->getChild(i), iter.currentTree(), visited, highGlobalIndex, self(), visitCount))
                  containsFloatingPoint = true;
               if (highGlobalIndex)
                  {
                  dumpOptDetails(comp(),
                     "%sGlobal index limit exceeded; stopping\n",
                     optDetailString());
                  return 0;
                  }
               }

            if (seenConditionalBranch &&
                containsFloatingPoint)
               {
               if (!cg()->getSupportsJavaFloatSemantics())
                  treeTopCanBeEliminated = false;
               }
            }
         }

      // Update visitCount as they are used in this optimization and need to be
      // correct at all intermediate stages
      //
      if (!treeTopCanBeEliminated)
         TR::TransformUtil::recursivelySetNodeVisitCount(node, visitCount);

      if (treeTopCanBeEliminated)
         {
         TR::TreeTop *prevTree = iter.currentTree()->getPrevTreeTop();
         TR::TreeTop *nextTree = iter.currentTree()->getNextTreeTop();

         if (!node->getOpCode().isStoreReg() || (node->getFirstChild()->getReferenceCount() == 1))
            {
            // Actually going to remove the treetop now
            //
            if (performTransformation(comp(), "%sRemove tree : [" POINTER_PRINTF_FORMAT "] ([" POINTER_PRINTF_FORMAT "] = %s)\n", optDetailString(), node, node->getFirstChild(), node->getFirstChild()->getOpCode().getName()))
               {
               prevTree->join(nextTree);
               optimizer()->prepareForNodeRemoval(node);
               ///child->recursivelyDecReferenceCount();
               node->recursivelyDecReferenceCount();
               recursivelyDecFutureUseCount(child);
               iter.jumpTo(prevTree);
               if (child->getReferenceCount() == 1)
                  requestOpt(OMR::treeSimplification, true, block);

               if (nextTree->getNode()->getOpCodeValue() == TR::Goto
                   && prevTree->getNode()->getOpCodeValue() == TR::BBStart
                   && !prevTree->getNode()->getBlock()->isExtensionOfPreviousBlock())
                  {
                  requestOpt(
                     OMR::redundantGotoElimination,
                     prevTree->getNode()->getBlock());
                  }
               }
            }
         else
            {
            if (performTransformation(comp(), "%sMove tree : [" POINTER_PRINTF_FORMAT "]([" POINTER_PRINTF_FORMAT "] = %s) to end of block\n", optDetailString(), node, node->getFirstChild(), node->getFirstChild()->getOpCode().getName()))
               {
               prevTree->join(nextTree);
               node->setVisitCount(visitCount);

               TR::TreeTop *lastTree = findLastTreetop(block, prevTree);
               TR::TreeTop *prevLastTree = lastTree->getPrevTreeTop();

               TR::TreeTop *cursorTreeTop = nextTree;
               while (cursorTreeTop != lastTree)
                  {
                  if (cursorTreeTop->getNode()->getOpCode().isStoreReg() &&
                      (cursorTreeTop->getNode()->getGlobalRegisterNumber() == iter.currentTree()->getNode()->getGlobalRegisterNumber()))
                     {
                     lastTree = cursorTreeTop;
                     prevLastTree = lastTree->getPrevTreeTop();
                     break;
                     }

                  cursorTreeTop = cursorTreeTop->getNextTreeTop();
                  }

               if (lastTree->getNode()->getOpCodeValue() == TR::BBStart)
                  {
                  prevLastTree = lastTree;
                  lastTree = block->getExit();
                  }

               TR::Node *lastNode = lastTree->getNode();
               TR::Node *prevLastNode = prevLastTree->getNode();

               if (lastNode->getOpCode().isIf() && !lastNode->getOpCode().isCompBranchOnly() &&
                   prevLastNode->getOpCode().isStoreReg() &&
                   ((prevLastNode->getFirstChild() == lastNode->getFirstChild()) ||
                    (prevLastNode->getFirstChild() == lastNode->getSecondChild())))
                  {
                  lastTree = prevLastTree;
                  prevLastTree = lastTree->getPrevTreeTop();
                  }

               prevLastTree->join(iter.currentTree());
               iter.currentTree()->join(lastTree);

               iter.jumpTo(prevTree);
               requestOpt(OMR::treeSimplification, true, block);
               }
            }
         }
      }

   for (auto it = anchors.begin(); it != anchors.end(); ++it)
      {
      TR::Node *anchor = it->tree->getNode();
      TR::Node *load = anchor->getChild(0);
      if (load->getReferenceCount() > 1)
         continue;

      // We can eliminate the indirect load immediately, but for the moment the
      // subtree providing the base object has to be anchored.

      TR::Node *heapBase = anchor->getChild(1);

      TR::Node::recreate(anchor, TR::treetop);
      anchor->setAndIncChild(0, load->getChild(0));
      anchor->setChild(1, NULL);
      anchor->setNumChildren(1);

      if (!heapBase->getOpCode().isLoadConst())
         {
         it->tree->insertAfter(
            TR::TreeTop::create(
               comp(),
               TR::Node::create(heapBase, TR::treetop, 1, heapBase)));
         }

      load->recursivelyDecReferenceCount();
      heapBase->recursivelyDecReferenceCount();

      // A later pass of dead trees can likely move (or even remove) the base
      // object expression.

      requestOpt(OMR::deadTreesElimination, true, it->block);
      }

   return 1; // actual cost
   }
示例#12
0
void TR::DeadTreesElimination::prePerformOnBlocks()
   {
   _cannotBeEliminated = false;
   _delayedRegStores = false;

   _targetTrees.deleteAll();

   // Walk through all the blocks to remove trivial dead trees of the form
   // treetop
   //   => node
   // The problem with these trees is in the scenario where the earlier use
   // of 'node' is also dead.  However, our analysis won't find that because
   // the reference count is > 1.
   vcount_t visitCount = comp()->incOrResetVisitCount();
   for (TR::TreeTop *tt = comp()->getStartTree();
        tt != 0;
        tt = tt->getNextTreeTop())
      {
      bool removed = false;

      TR::Node *node = tt->getNode();
      if (node->getOpCodeValue() == TR::treetop &&
          node->getFirstChild()->getVisitCount() == visitCount &&
          performTransformation(comp(), "%sRemove trivial dead tree: %p\n", optDetailString(), node))
         {
         TR::TransformUtil::removeTree(comp(), tt);
         removed = true;
         }
      else
         {
         if (node->getOpCode().isCheck() &&
             node->getFirstChild()->getOpCode().isCall() &&
             node->getFirstChild()->getReferenceCount() == 1 &&
             node->getFirstChild()->getSymbolReference()->getSymbol()->isResolvedMethod() &&
             node->getFirstChild()->getSymbolReference()->getSymbol()->castToResolvedMethodSymbol()->isSideEffectFree() &&
             performTransformation(comp(), "%sRemove dead check of side-effect free call: %p\n", optDetailString(), node))
            {
            TR::TransformUtil::removeTree(comp(), tt);
            removed = true;
            }
         }

      if (removed
          && tt->getNextTreeTop()->getNode()->getOpCodeValue() == TR::Goto
          && tt->getPrevTreeTop()->getNode()->getOpCodeValue() == TR::BBStart
          && !tt->getPrevTreeTop()->getNode()->getBlock()->isExtensionOfPreviousBlock())
         {
         requestOpt(OMR::redundantGotoElimination, tt->getEnclosingBlock());
         }

      if (node->getVisitCount() >= visitCount)
         continue;
      TR::TransformUtil::recursivelySetNodeVisitCount(tt->getNode(), visitCount);
      }

   // If the last use of an iRegLoad has been removed, then remove the node from
   // the BBStart and remove the corresponding dependency node from each of the block's
   // predecessors.
   //
   while (1)
      {
      bool glRegDepRemoved = false;
      for (TR::Block * b = comp()->getStartBlock(); b; b = b->getNextBlock())
         {
         TR::TreeTop * startTT = b->getEntry();
         TR::Node * startNode = startTT->getNode();
         if (startNode->getNumChildren() > 0 && !debug("disableEliminationOfGlRegDeps"))
            {
            TR::Node * glRegDeps = startNode->getFirstChild();
            TR_ASSERT(glRegDeps->getOpCodeValue() == TR::GlRegDeps, "expected TR::GlRegDeps");
            for (int32_t i = glRegDeps->getNumChildren() - 1; i >= 0; --i)
               {
               TR::Node * dep = glRegDeps->getChild(i);
               if (dep->getReferenceCount() == 1 &&
                   (!dep->getOpCode().isFloatingPoint() ||
                    cg()->getSupportsJavaFloatSemantics()) &&
                   performTransformation(comp(), "%sRemove GlRegDep : %p\n", optDetailString(), glRegDeps->getChild(i)))

                  {
                  glRegDeps->removeChild(i);
                  glRegDepRemoved = true;
                  TR_GlobalRegisterNumber registerNum = dep->getGlobalRegisterNumber();
                  for (auto e = b->getPredecessors().begin(); e != b->getPredecessors().end(); ++e)
                     {
                     TR::Block * pred = toBlock((*e)->getFrom());
                     if (pred == comp()->getFlowGraph()->getStart())
                        continue;

                     TR::Node * parent = pred->getLastRealTreeTop()->getNode();
                     if ( parent->getOpCode().isJumpWithMultipleTargets() && parent->getOpCode().hasBranchChildren())
                        {
                        for (int32_t j = parent->getCaseIndexUpperBound() - 1; j > 0; --j)
                           {
                           TR::Node * caseNode = parent->getChild(j);
                           TR_ASSERT(caseNode->getOpCode().isCase() || caseNode->getOpCodeValue() == TR::branch,
                                  "having problems navigating a switch");
                           if (caseNode->getBranchDestination() == startTT &&
                               caseNode->getNumChildren() > 0 &&
                               0) // can't do this now that all glRegDeps are hung off the default branch
                              removeGlRegDep(caseNode, registerNum, pred, this);
                           }
                        }
                     else if (!parent->getOpCode().isReturn() &&
                              parent->getOpCodeValue() != TR::igoto &&
                              !( parent->getOpCode().isJumpWithMultipleTargets() && parent->getOpCode().hasBranchChildren()) &&
                              !(parent->getOpCodeValue()==TR::treetop &&
                              parent->getFirstChild()->getOpCode().isCall() &&
                              parent->getFirstChild()->getOpCode().isIndirect()))

                        {
                        if (pred->getNextBlock() == b)
                           parent = pred->getExit()->getNode();
                        removeGlRegDep(parent, registerNum, pred, this);
                        }
                     }
                  }
               }

            if (glRegDeps->getNumChildren() == 0)
               startNode->removeChild(0);
            }
         }

      if (!glRegDepRemoved)
         break;
      }
   }