Ejemplo n.º 1
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();
      }

   }
Ejemplo n.º 2
0
void TR_ReachingDefinitions::initializeGenAndKillSetInfo()
   {
   // For each block in the CFG build the gen and kill set for this analysis.
   // Go in treetop order, which guarantees that we see the correct (i.e. first)
   // evaluation point for each node.
   //
   TR::Block *block;
   int32_t   blockNum = 0;
   bool      seenException = false;
   TR_BitVector defsKilled(getNumberOfBits(), trMemory()->currentStackRegion());

   comp()->incVisitCount();
   for (TR::TreeTop *treeTop = comp()->getStartTree(); treeTop; treeTop = treeTop->getNextTreeTop())
      {
      TR::Node *node = treeTop->getNode();

      if (node->getOpCodeValue() == TR::BBStart)
         {
         block = node->getBlock();
         blockNum = block->getNumber();
         seenException  = false;
         if (traceRD())
            traceMsg(comp(), "\nNow generating gen and kill information for block_%d\n", blockNum);
         continue;
         }

#if DEBUG
      if (node->getOpCodeValue() == TR::BBEnd && traceRD())
         {
         traceMsg(comp(), "  Block %d:\n", blockNum);
         traceMsg(comp(), "     Gen set ");
         if (_regularGenSetInfo[blockNum])
            _regularGenSetInfo[blockNum]->print(comp());
         else
            traceMsg(comp(), "{}");
         traceMsg(comp(), "\n     Kill set ");
         if (_regularKillSetInfo[blockNum])
            _regularKillSetInfo[blockNum]->print(comp());
         else
            traceMsg(comp(), "{}");
         traceMsg(comp(), "\n     Exception Gen set ");
         if (_exceptionGenSetInfo[blockNum])
            _exceptionGenSetInfo[blockNum]->print(comp());
         else
            traceMsg(comp(), "{}");
         traceMsg(comp(), "\n     Exception Kill set ");
         if (_exceptionKillSetInfo[blockNum])
            _exceptionKillSetInfo[blockNum]->print(comp());
         else
            traceMsg(comp(), "{}");
         continue;
         }
#endif

      initializeGenAndKillSetInfoForNode(node, defsKilled, seenException, blockNum, NULL);

      if (!seenException && treeHasChecks(treeTop))
         seenException = true;
      }
   }
Ejemplo n.º 3
0
int32_t TR_AsyncCheckInsertion::insertReturnAsyncChecks(TR::Optimization *opt, const char *counterPrefix)
   {
   TR::Compilation * const comp = opt->comp();
   if (opt->trace())
      traceMsg(comp, "Inserting return asyncchecks (%s)\n", counterPrefix);

   int numAsyncChecksInserted = 0;
   for (TR::TreeTop *treeTop = comp->getStartTree();
        treeTop;
        /* nothing */ )
      {
      TR::Block *block = treeTop->getNode()->getBlock();
      if (block->getLastRealTreeTop()->getNode()->getOpCode().isReturn()
          && performTransformation(comp,
               "%sInserting return asynccheck (%s) in block_%d\n",
               opt->optDetailString(),
               counterPrefix,
               block->getNumber()))
         {
         insertAsyncCheck(block, comp, counterPrefix);
         numAsyncChecksInserted++;
         }

      treeTop = block->getExit()->getNextRealTreeTop();
      }
   return numAsyncChecksInserted;
   }
Ejemplo n.º 4
0
static void resetBlockVisitFlags(TR::Compilation *comp)
   {
   for (TR::Block *block = comp->getStartBlock(); block != NULL; block = block->getNextBlock())
      {
      block->setHasBeenVisited(false);
      }
   }
Ejemplo n.º 5
0
// Process the structure recursively
//
int32_t
TR_ExpressionsSimplification::perform(TR_Structure * str)
   {
   if (trace())
      traceMsg(comp(), "Analyzing root Structure : %p\n", str);

   TR_RegionStructure *region;

   // Only regions can be simplified
   //
   if (!(region = str->asRegion()))
      return 0;

   TR_RegionStructure::Cursor it(*region);

   for (TR_StructureSubGraphNode *node = it.getCurrent();
        node != 0;
        node = it.getNext())
      {
      // Too strict
      /*
      if ((node->getPredecessors().size() == 1))
         {
         TR::CFGEdge *edge = node->getPredecessors().front();
         TR_StructureSubGraphNode *pred = toStructureSubGraphNode(edge->getFrom());
         TR_BlockStructure *b = pred->getStructure()->asBlock();
         if (b && pred->getSuccessors().size() == 1))
            perform(node->getStructure());
         }
      */
      perform(node->getStructure());
      }

   // debug only
   //
   /*
   if (region->isNaturalLoop() &&
          (region->getParent()  &&
            !region->getParent()->asRegion()->isCanonicalizedLoop()))
      {
      traceMsg(comp(), "Loop not canonicalized %x\n", region);
      }
   */

   TR::Block *entryBlock = region->getEntryBlock();
   if (region->isNaturalLoop() && !entryBlock->isCold() &&
          (region->getParent() /* &&
            region->getParent()->asRegion()->isCanonicalizedLoop() */))
         {
         if (trace())
           traceMsg(comp(), "Found candidate non cold loop %p for expression elimination\n", region);

         findAndSimplifyInvariantLoopExpressions(region);
         }

   return 1;  // Need to specify the cost
   }
Ejemplo n.º 6
0
TR::TreeTop *
OMR::TreeTop::getExtendedBlockExitTreeTop()
   {
   TR_ASSERT(self()->getNode()->getOpCodeValue() == TR::BBStart, "getExitTreeTop, is only valid for a bbStart");
   TR::Block * b;
   TR::TreeTop * exitTT = self()->getNode()->getBlock()->getExit(), * nextTT;
   while ((nextTT = exitTT->getNextTreeTop()) && (b = nextTT->getNode()->getBlock(), b->isExtensionOfPreviousBlock()))
      exitTT = b->getExit();
   return exitTT;
   }
Ejemplo n.º 7
0
void
TR_ForwardReachabilityWithoutExceptionEdges::propagateInputs(blocknum_t blockNum, int32_t depth, blocknum_t *stack, blocknum_t *depth_map, TR_BitVector *closure)
   {
   TR::Block *block = getBlock(blockNum);
   for (auto edge = block->getPredecessors().begin(); edge != block->getPredecessors().end(); ++edge)
      {
      TR::Block *inputBlock = toBlock((*edge)->getFrom());
      propagateOneInput(inputBlock->getNumber(), blockNum, depth, stack, depth_map, closure);
      }
   }
Ejemplo n.º 8
0
void
TR_BackwardReachability::propagateInputs(blocknum_t blockNum, int32_t depth, blocknum_t *stack, blocknum_t *depth_map, TR_BitVector *closure)
   {
   TR::Block *block = getBlock(blockNum);
   TR_SuccessorIterator bi(block);
   for (TR::CFGEdge *edge = bi.getFirst(); edge != NULL; edge = bi.getNext())
      {
      TR::Block *inputBlock = toBlock(edge->getTo());
      propagateOneInput(inputBlock->getNumber(), blockNum, depth, stack, depth_map, closure);
      }
   }
Ejemplo n.º 9
0
void
TR::RegDepCopyRemoval::makeFreshCopy(TR_GlobalRegisterNumber reg)
   {
   RegDepInfo &dep = getRegDepInfo(reg);
   if (!performTransformation(comp(),
         "%schange %s in GlRegDeps n%un to an explicit copy of n%un\n",
         optDetailString(),
         registerName(reg),
         _regDeps->getGlobalIndex(),
         dep.value->getGlobalIndex()))
      return;

   // Split the block at fallthrough if necessary to avoid putting copies
   // between branches and BBEnd.
   TR::Node *curNode = _treetop->getNode();
   if (curNode->getOpCodeValue() == TR::BBEnd)
      {
      TR::Block *curBlock = curNode->getBlock();
      if (curBlock->getLastRealTreeTop() != curBlock->getLastNonControlFlowTreeTop())
         {
         TR::Block *fallthrough = curBlock->getNextBlock();
         fallthrough = curBlock->splitEdge(curBlock, fallthrough, comp());
         TR_ASSERT(curBlock->getNextBlock() == fallthrough, "bad block placement from splitEdge\n");
         fallthrough->setIsExtensionOfPreviousBlock();
         _treetop = fallthrough->getExit();
         TR::Node *newNode = _treetop->getNode();
         newNode->setChild(0, _regDeps);
         newNode->setNumChildren(1);
         curNode->setNumChildren(0);
         if (trace())
            traceMsg(comp(), "\tsplit fallthrough edge to insert copy, created block_%d\n", fallthrough->getNumber());
         }
      }

   // Make and insert the copy
   TR::Node *copyNode = NULL;
   if (dep.value->getOpCode().isLoadConst())
      {
      // No need to depend on the other register.
      // TODO heuristic for whether this is really better than a reg-reg move?
      generateRegcopyDebugCounter("const-remat");
      copyNode = TR::Node::create(dep.value->getOpCodeValue(), 0);
      copyNode->setConstValue(dep.value->getConstValue());
      }
   else
      {
      generateRegcopyDebugCounter("fresh-copy");
      copyNode = TR::Node::create(TR::PassThrough, 1, dep.value);
      copyNode->setCopyToNewVirtualRegister();
      }

   TR::Node *copyTreetopNode = TR::Node::create(TR::treetop, 1, copyNode);
   _treetop->insertBefore(TR::TreeTop::create(comp(), copyTreetopNode));
   if (trace())
      traceMsg(comp(), "\tcopy is n%un\n", copyNode->getGlobalIndex());

   updateSingleRegDep(reg, copyNode);
   }
Ejemplo n.º 10
0
void
TR_ExpressionsSimplification::removeUncertainBlocks(TR_RegionStructure* region, List<TR::Block> *candidateBlocksList)
   {
   // Examine the top region block first
   //
   TR::Block *entryBlock = _currentRegion->getEntryBlock();
   ListIterator<TR::Block> blocks;
   blocks.set(candidateBlocksList);

   if (trace())
      traceMsg(comp(), "Number of blocks %d, entry block number %d\n", candidateBlocksList->getSize(), entryBlock->getNumber());

   for (TR::Block *block = blocks.getFirst(); block; block = blocks.getNext())
      {
      TR::CFGNode *cfgNode = block;
      if (!(cfgNode->getExceptionSuccessors().empty()) || blockHasCalls(block, comp()))
         {
         if (trace())
            traceMsg(comp(), "An exception can be thrown from block_%d. Removing all the blocks, since we cannot know the number of iterations.\n", block->getNumber());
         candidateBlocksList->deleteAll();
         break;
         }
      }

   TR_PostDominators postDominators(comp());
   if (postDominators.isValid())
      {
	  postDominators.findControlDependents();
      for (TR::Block *block = blocks.getFirst(); block; block = blocks.getNext())
         {
         if (postDominators.dominates(block, entryBlock) == 0)
            {
            candidateBlocksList->remove(block);
            if (trace())
               traceMsg(comp(), "Block_%d is not guaranteed to be executed at least once. Removing it from the list.\n", block->getNumber());
            }
         }
      }
   else
      {
	  if (trace())
	     traceMsg(comp(), "There is no post dominators information. Removing all the blocks.\n");
	  for (TR::Block *block = blocks.getFirst(); block; block = blocks.getNext())
	     {
	     candidateBlocksList->remove(block);
	     if (trace())
	        traceMsg(comp(), "Block_%d is removed from the list\n", block->getNumber());
	     }
      }
   }
Ejemplo n.º 11
0
void TR_LocalAnalysis::initializeBlocks(TR::Block *block, TR::BitVector &blocksSeen)
   {
   _info[block->getNumber()]._block = block;
   blocksSeen[block->getNumber()] = true;

   TR::Block                *next;
   for (auto nextEdge = block->getSuccessors().begin(); nextEdge != block->getSuccessors().end(); ++nextEdge)
      {
      next = toBlock((*nextEdge)->getTo());
      if (!blocksSeen.ValueAt(next->getNumber()))
         initializeBlocks(next, blocksSeen);
      }
   for (auto nextEdge = block->getExceptionSuccessors().begin(); nextEdge != block->getExceptionSuccessors().end(); ++nextEdge)
      {
      next = toBlock((*nextEdge)->getTo());
      if (!blocksSeen.ValueAt(next->getNumber()))
         initializeBlocks(next, blocksSeen);
      }
   }
Ejemplo n.º 12
0
int32_t TR_LocalLiveRangeReduction::perform()
   {
   if (TR::Compiler->target.cpu.isZ())
      return false;

   TR::TreeTop * exitTT, * nextTT;
   TR::Block *b;
   TR::TreeTop * tt;

   //calculate number of TreeTops in each bb (or extended bb)
   for (tt = comp()->getStartTree(); tt; tt = nextTT)
      {
      TR::StackMemoryRegion stackMemoryRegion(*trMemory());

      TR::Node *node = tt->getNode();
      b = node->getBlock();
      exitTT = b->getExit();
      _numTreeTops = b->getNumberOfRealTreeTops()+2; //include both BBStart/BBend

      //support for extended blocks
      while ((nextTT = exitTT->getNextTreeTop()) && (b = nextTT->getNode()->getBlock(), b->isExtensionOfPreviousBlock()))
         {

         _numTreeTops += b->getNumberOfRealTreeTops()+2;
         exitTT = b->getExit();
         }

      _treesRefInfoArray = (TR_TreeRefInfo**)trMemory()->allocateStackMemory(_numTreeTops*sizeof(TR_TreeRefInfo*));
      memset(_treesRefInfoArray, 0, _numTreeTops*sizeof(TR_TreeRefInfo*));
      _movedTreesList.deleteAll();
      _depPairList.deleteAll();
      transformExtendedBlock(tt,exitTT->getNextTreeTop());
      }

   if (trace())
      traceMsg(comp(), "\nEnding LocalLiveRangeReducer\n");

   return 2;
   }
Ejemplo n.º 13
0
void
TR_ExpressionsSimplification::invalidateCandidates()
   {
   _visitCount = comp()->incVisitCount();

   if (trace())
      {
      traceMsg(comp(), "Checking which candidates may be invalidated\n");

      ListIterator<TR::TreeTop> treeTops(_candidateTTs);
      for (TR::TreeTop *treeTop = treeTops.getFirst(); treeTop; treeTop = treeTops.getNext())
         {
         traceMsg(comp(), "   Candidate treetop: %p node: %p\n", treeTop, treeTop->getNode());
         }
      }

   TR_ScratchList<TR::Block> blocksInLoop(trMemory());
   _currentRegion->getBlocks(&blocksInLoop);
   ListIterator<TR::Block> blocks(&blocksInLoop);

   for (TR::Block *currentBlock = blocks.getFirst(); currentBlock; currentBlock  = blocks.getNext())
      {
      TR::TreeTop *tt = currentBlock->getEntry();
      TR::TreeTop *exitTreeTop = currentBlock->getExit();
      while (tt != exitTreeTop)
         {
         TR::Node *currentNode = tt->getNode();

         if (trace())
            traceMsg(comp(), "Looking at treeTop [%p]\n", currentNode);

         removeCandidate(currentNode, tt);

         tt = tt->getNextTreeTop();
         }
      }
   removeUnsupportedCandidates();
   }
Ejemplo n.º 14
0
TR::Block *
TR_ExpressionsSimplification::findPredecessorBlock(TR::CFGNode *entryNode)
   {
   if (!(entryNode->getPredecessors().size() == 2))
       return 0;


   TR::Block *block = 0;

   for (auto edge = entryNode->getPredecessors().begin(); edge != entryNode->getPredecessors().end(); ++edge)
      {
      if ((*edge)->getFrom()->getSuccessors().size() == 1)
         {
         block = toBlock((*edge)->getFrom());
         if (block->getStructureOf()->isLoopInvariantBlock())
            break;
         else
            block = 0;
         }
      }
   //traceMsg(comp(), "Commoned code will be put in block_%d\n", block->getNumber());
   return block;
   }
Ejemplo n.º 15
0
void
TR_ReachabilityAnalysis::perform(TR_BitVector *result)
   {
   TR::CFG *cfg = comp()->getFlowGraph();
   int32_t numBlockIndexes = cfg->getNextNodeNumber();
   int32_t numBlocks       = cfg->getNumberOfNodes();

   _blocks = cfg->createArrayOfBlocks();

   blocknum_t *stack    = (blocknum_t*)comp()->trMemory()->allocateStackMemory(numBlockIndexes * sizeof(stack[0]));
   blocknum_t *depthMap = (blocknum_t*)comp()->trMemory()->allocateStackMemory(numBlockIndexes * sizeof(depthMap[0]));
   memset(depthMap, 0, numBlockIndexes * sizeof(depthMap[0]));

   bool trace = comp()->getOption(TR_TraceReachability);

   if (trace)
      traceMsg(comp(), "BEGIN REACHABILITY: %d blocks\n", numBlocks);

   for (TR::Block *block = comp()->getStartBlock(); block; block = block->getNextBlock())
      {
      blocknum_t blockNum = block->getNumber();
      if (trace)
         traceMsg(comp(), "Visit block_%d\n", blockNum);
      if (depthMap[blockNum] == 0)
         traverse(blockNum, 0, stack, depthMap, result);
      else
         traceMsg(comp(), "  depth is already %d; skip\n", depthMap[blockNum]);
      }

   if (comp()->getOption(TR_TraceReachability))
      {
      traceMsg(comp(), "END REACHABILITY.  Result:\n");
      result->print(comp(), comp()->getOutFile());
      traceMsg(comp(), "\n");
      }
   }
Ejemplo n.º 16
0
void TR_ExpressionsSimplification::tranformStoreMotionCandidate(TR::TreeTop *treeTop, bool *isPreheaderBlockInvalid)
   {
   TR::Node *node = treeTop->getNode();

   TR_ASSERT(node->getOpCode().isStore() && !node->getSymbol()->isStatic() && !node->getSymbol()->holdsMonitoredObject(),
      "node %p was expected to be a non-static non-monitored object store and was not.", node);

   // this candidate should be valid, either direct or indirect

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

   TR::Block *entryBlock = _currentRegion->getEntryBlock();
   TR::Block *preheaderBlock = findPredecessorBlock(entryBlock);

   if (!preheaderBlock)
      {
      if (trace())
         traceMsg(comp(), "Fail to find a place to put the hoist code in\n");
      *isPreheaderBlockInvalid = true;
      return;
      }

   // Earlier post-dominance test ensures that the loop is executed as least once, or is canonicalized.
   // but to be safe we still perform on canonicalized loops only.
   if (_currentRegion->isCanonicalizedLoop())  // make sure that the loop is canonicalized, in which case the preheader is
      {                                        // executed in its first iteration and is protected.
      if (performTransformation(comp(), "%sMove out loop-invariant store [%p] to block_%d\n", OPT_DETAILS, node, preheaderBlock->getNumber()))
         {
         TR::Node *newNode = node->duplicateTree();
         transformNode(newNode, preheaderBlock);
         TR::TransformUtil::removeTree(comp(), treeTop);
         }
      }
   else
      {
      if (trace())
         traceMsg(comp(), "No canonicalized loop for this candidate\n");
      }
   }
Ejemplo n.º 17
0
static void moveBlockAfterDest(TR::CFG *cfg, TR::Block *toMove, TR::Block *dest)
   {
   TR::Compilation *comp = TR::comp();
   // Step1 splice out toMove
   TR::Block *toMovePrev = toMove->getPrevBlock();
   TR::Block *toMoveSucc = toMove->getNextBlock();

   toMovePrev->getExit()->join(toMoveSucc->getEntry());

   // Step 2 splice toMove in after dest
   TR::Block *destNext = dest->getNextBlock();
   dest->getExit()->join(toMove->getEntry());
   toMove->getExit()->join(destNext->getEntry());

   cfg->addEdge(toMove, destNext);
   cfg->addEdge(dest, toMove);
   cfg->removeEdge(dest, destNext);

   cfg->addEdge(toMovePrev, toMoveSucc);
   cfg->removeEdge(toMovePrev, toMove);
   cfg->removeEdge(toMove, toMoveSucc);
   }
Ejemplo n.º 18
0
/**
 * Search for direct loads in the taken side of a guard
 *
 * @param firstBlock The guard's branch destination
 * @param coldPathLoads BitVector of symbol reference numbers for any direct loads seen until the merge back to mainline
 */
static void collectColdPathLoads(TR::Block* firstBlock, TR_BitVector &coldPathLoads)
   {
   TR_Stack<TR::Block*> blocksToCheck(TR::comp()->trMemory(), 8, false, stackAlloc);
   blocksToCheck.push(firstBlock);
   TR::NodeChecklist checklist(TR::comp());

   coldPathLoads.empty();
   while (!blocksToCheck.isEmpty())
      {
      TR::Block *block = blocksToCheck.pop();

      for (TR::TreeTop *tt = block->getFirstRealTreeTop(); tt->getNode()->getOpCodeValue() != TR::BBEnd; tt = tt->getNextTreeTop())
         collectDirectLoads(tt->getNode(), coldPathLoads, checklist);

      // Search for any successors that have not merged with the mainline
      for (auto itr = block->getSuccessors().begin(), end = block->getSuccessors().end(); itr != end; ++itr)
         {
         TR::Block *dest = (*itr)->getTo()->asBlock();
         if (dest != TR::comp()->getFlowGraph()->getEnd() && dest->getPredecessors().size() == 1)
            blocksToCheck.push(dest);
         }
      }
   }
Ejemplo n.º 19
0
int32_t TR_CatchBlockRemover::perform()
   {
   TR::CFG *cfg = comp()->getFlowGraph();
   if (cfg == NULL)
      {
      if (trace())
         traceMsg(comp(), "Can't do Catch Block Removal, no CFG\n");
      return 0;
      }

   if (trace())
      traceMsg(comp(), "Starting Catch Block Removal\n");

   bool thereMayBeRemovableCatchBlocks = false;

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

   TR::Block *block;
   ListIterator<TR::CFGEdge> edgeIterator;

   // Go through all blocks that have exception successors and see if any of them
   // are not reached. Mark each of these edges with a visit count so they can
   // be identified later.
   //
   vcount_t visitCount = comp()->incOrResetVisitCount();

   TR::CFGNode *cfgNode;
   for (cfgNode = cfg->getFirstNode(); cfgNode; cfgNode = cfgNode->getNext())
      {
      if (cfgNode->getExceptionSuccessors().empty())
         continue;

      block = toBlock(cfgNode);
      uint32_t reachedExceptions = 0;
      TR::TreeTop *treeTop;
      for (treeTop = block->getEntry(); treeTop != block->getExit(); treeTop = treeTop->getNextTreeTop())
         {
         reachedExceptions |= treeTop->getNode()->exceptionsRaised();

         if (treeTop->getNode()->getOpCodeValue() == TR::monexitfence) // for live monitor metadata
            reachedExceptions |= TR::Block::CanCatchMonitorExit;
         }

      if (reachedExceptions & TR::Block::CanCatchUserThrows)
         continue;

      for (auto edge = block->getExceptionSuccessors().begin(); edge != block->getExceptionSuccessors().end();)
         {
         TR::CFGEdge * current = *(edge++);
         TR::Block *catchBlock = toBlock(current->getTo());
         if (catchBlock->isOSRCodeBlock() || catchBlock->isOSRCatchBlock()) continue;
         if (!reachedExceptions &&
             performTransformation(comp(), "%sRemove redundant exception edge from block_%d at [%p] to catch block_%d at [%p]\n", optDetailString(), block->getNumber(), block, catchBlock->getNumber(), catchBlock))
            {
            cfg->removeEdge(block, catchBlock);
            thereMayBeRemovableCatchBlocks = true;
            }
         else
            {
            if (!catchBlock->canCatchExceptions(reachedExceptions))
               {
               current->setVisitCount(visitCount);
               thereMayBeRemovableCatchBlocks = true;
               }
            }
         }
      }

   bool edgesRemoved = false;

   // Now look to see if there are any catch blocks for which all exception
   // predecessors have the visit count set. If so, the block is unreachable and
   // can be removed.
   // If only some of the exception predecessors are marked, these edges are
   // left in place to identify the try/catch structure properly.
   //
   while (thereMayBeRemovableCatchBlocks)
      {
      thereMayBeRemovableCatchBlocks = false;
      for (cfgNode = cfg->getFirstNode(); cfgNode; cfgNode = cfgNode->getNext())
         {
         if (cfgNode->getExceptionPredecessors().empty())
            continue;
         auto edgeIt = cfgNode->getExceptionPredecessors().begin();
         for (; edgeIt != cfgNode->getExceptionPredecessors().end(); ++edgeIt)
            {
            if ((*edgeIt)->getVisitCount() != visitCount)
               break;
            }

         if (edgeIt == cfgNode->getExceptionPredecessors().end() && performTransformation(comp(), "%sRemove redundant catch block_%d at [%p]\n", optDetailString(), cfgNode->getNumber(), cfgNode))
            {
            while (!cfgNode->getExceptionPredecessors().empty())
               {
               cfg->removeEdge(cfgNode->getExceptionPredecessors().front());
               }
            edgesRemoved = true;
            thereMayBeRemovableCatchBlocks = true;
            }
         }
      }


   // Any transformations invalidate use/def and value number information
   //
   if (edgesRemoved)
      {
      optimizer()->setUseDefInfo(NULL);
      optimizer()->setValueNumberInfo(NULL);
      requestOpt(OMR::treeSimplification, true);
      }

   } // scope of the stack memory region

   if (trace())
      traceMsg(comp(), "\nEnding Catch Block Removal\n");

   return 1; // actual cost
   }
Ejemplo n.º 20
0
TR_GlobalRegisterNumber
OMR::X86::I386::CodeGenerator::pickRegister(
      TR_RegisterCandidate *rc,
      TR::Block **allBlocks,
      TR_BitVector &availableRegisters,
      TR_GlobalRegisterNumber &highRegisterNumber,
      TR_LinkHead<TR_RegisterCandidate> *candidates)
   {
   if (!self()->comp()->getOption(TR_DisableRegisterPressureSimulation))
      {
      if (self()->comp()->getOption(TR_AssignEveryGlobalRegister))
         {
         // This is not really necessary except for testing purposes.
         // Conceptually, the common pickRegister code should be free to make
         // its choices based only on performance considerations, and shouldn't
         // need to worry about correctness.  When SupportsVMThreadGRA is not set,
         // it is incorrect to choose the VMThread register.  Therefore we mask
         // it out here.
         //
         // Having said that, the common code *does* already mask out the
         // VMThread register for convenience, so under normal circumstances,
         // this code is redundant.  It is only necessary when
         // TR_AssignEveryGlobalRegister is set.
         //
         availableRegisters -= *self()->getGlobalRegisters(TR_vmThreadSpill, self()->comp()->getMethodSymbol()->getLinkageConvention());
         }
      return OMR::CodeGenerator::pickRegister(rc, allBlocks, availableRegisters, highRegisterNumber, candidates);
      }

   if ((rc->getSymbol()->getDataType() == TR::Float) ||
       (rc->getSymbol()->getDataType() == TR::Double))
      {
      if (availableRegisters.get(7))
         return 7;
      if (availableRegisters.get(8))
         return 8;
      if (availableRegisters.get(9))
         return 9;
      if (availableRegisters.get(10))
         return 10;
      if (availableRegisters.get(11))
         return 11;
      if (availableRegisters.get(12))
         return 12;

      return -1;
      }


   if (!_assignedGlobalRegisters)
      _assignedGlobalRegisters = new (self()->trStackMemory()) TR_BitVector(self()->comp()->getSymRefCount(), self()->trMemory(), stackAlloc, growable);

   if (availableRegisters.get(5))
      return 5; // esi

   if (availableRegisters.get(2))
      return 2; // ecx

   static char *dontUseEBXasGPR = feGetEnv("dontUseEBXasGPR");
   if (!dontUseEBXasGPR && availableRegisters.get(1))
      return 1;

#ifdef J9_PROJECT_SPECIFIC
   TR::RecognizedMethod rm = self()->comp()->getMethodSymbol()->getRecognizedMethod();
   if (rm == TR::java_util_HashtableHashEnumerator_hasMoreElements)
      {
      if (availableRegisters.get(4))
         return 4; // edi
      if (availableRegisters.get(3))
         return 3; // edx
      }
   else
#endif
      {
      int32_t numExtraRegs = 0;
      int32_t maxRegisterPressure = 0;

      vcount_t visitCount = self()->comp()->incVisitCount();
      TR_BitVectorIterator bvi(rc->getBlocksLiveOnEntry());
      int32_t maxFrequency = 0;
      while (bvi.hasMoreElements())
         {
         int32_t liveBlockNum = bvi.getNextElement();
         TR::Block *block = allBlocks[liveBlockNum];
         if (block->getFrequency() > maxFrequency)
             maxFrequency = block->getFrequency();
         }

      int32_t maxStaticFrequency = 0;
      if (maxFrequency == 0)
         {
         bvi.setBitVector(rc->getBlocksLiveOnEntry());
         while (bvi.hasMoreElements())
            {
            int32_t liveBlockNum = bvi.getNextElement();
            TR::Block *block = allBlocks[liveBlockNum];
            TR_BlockStructure *blockStructure = block->getStructureOf();
            int32_t blockWeight = 1;
            if (blockStructure &&
                !block->isCold())
               {
               blockStructure->calculateFrequencyOfExecution(&blockWeight);
               if (blockWeight > maxStaticFrequency)
                  maxStaticFrequency = blockWeight;
               }
            }
         }

      bool assigningEDX = false;
      if (!availableRegisters.get(4) &&
          availableRegisters.get(3))
         assigningEDX = true;

      bool vmThreadUsed = false;

      bvi.setBitVector(rc->getBlocksLiveOnEntry());
      while (bvi.hasMoreElements())
         {
         int32_t liveBlockNum = bvi.getNextElement();
         TR::Block *block = allBlocks[liveBlockNum];

         _assignedGlobalRegisters->empty();
         int32_t numAssignedGlobalRegs = 0;
         TR_RegisterCandidate *prev;
         for (prev = candidates->getFirst(); prev; prev = prev->getNext())
            {
            bool gprCandidate = true;
            if ((prev->getSymbol()->getDataType() == TR::Float) ||
                (prev->getSymbol()->getDataType() == TR::Double))
               gprCandidate = false;
            if (gprCandidate && prev->getBlocksLiveOnEntry().get(liveBlockNum))
               {
               numAssignedGlobalRegs++;
               if (prev->getDataType() == TR::Int64)
                  numAssignedGlobalRegs++;
               _assignedGlobalRegisters->set(prev->getSymbolReference()->getReferenceNumber());
               }
            }

         maxRegisterPressure = self()->estimateRegisterPressure(block, visitCount, maxStaticFrequency, maxFrequency, vmThreadUsed, numAssignedGlobalRegs, _assignedGlobalRegisters, rc->getSymbolReference(), assigningEDX);

         if (maxRegisterPressure >= self()->getMaximumNumbersOfAssignableGPRs())
            break;
         }

      // Determine if we can spare any extra registers for this candidate without spilling
      // in any hot (critical) blocks
      //
      if (maxRegisterPressure < self()->getMaximumNumbersOfAssignableGPRs())
         numExtraRegs = self()->getMaximumNumbersOfAssignableGPRs() - maxRegisterPressure;

      //dumpOptDetails("For global register candidate %d reg pressure is %d maxRegs %d numExtraRegs %d\n", rc->getSymbolReference()->getReferenceNumber(), maxRegisterPressure, comp()->cg()->getMaximumNumbersOfAssignableGPRs(), numExtraRegs);

      if (numExtraRegs > 0)
         {
         if (availableRegisters.get(4))
            return 4; // edi

         if (availableRegisters.get(3))
            return 3; // edx
         }
      }

   return -1; // -1 ==> don't use a global register
   }
Ejemplo n.º 21
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
   }
Ejemplo n.º 22
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;
      }
   }
Ejemplo n.º 23
0
bool TR_ExpressionsSimplification::tranformSummationReductionCandidate(TR::TreeTop *treeTop, LoopInfo *loopInfo, bool *isPreheaderBlockInvalid)
   {
   TR::Node *node = treeTop->getNode();
   TR::Node *opNode = node->getFirstChild();
   TR::Node *expNode = NULL;
   int32_t expChildNumber = 0;
   bool removeOnly = false;
   bool replaceWithNewNode = false;

   if (opNode->getOpCodeValue() == TR::iadd || opNode->getOpCodeValue() == TR::isub)
      {
      if (opNode->getSecondChild()->getOpCode().hasSymbolReference() &&
            node->getSymbolReference() == opNode->getSecondChild()->getSymbolReference())
         {
         expChildNumber = 0;
         expNode = opNode->getFirstChild();
         }
      else
         {
         expChildNumber = 1;
         expNode = opNode->getSecondChild();
         }
      expNode = iaddisubSimplifier(expNode, loopInfo);
      replaceWithNewNode = true;
      }
   else if (opNode->getOpCodeValue() == TR::ixor || opNode->getOpCodeValue() == TR::ineg)
      {
      expNode = ixorinegSimplifier(opNode, loopInfo, &removeOnly);
      }

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

      TR::Block *entryBlock = _currentRegion->getEntryBlock();
      TR::Block *preheaderBlock = findPredecessorBlock(entryBlock);

      if (!preheaderBlock)
         {
         if (trace())
            traceMsg(comp(), "Fail to find a place to put the hoist code in\n");
         *isPreheaderBlockInvalid = true;
         return true;
         }

      if (loopInfo->getNumIterations() > 0 ||     // make sure that the loop is going to be executed at least once
            _currentRegion->isCanonicalizedLoop())  // or that the loop is canonicalized, in which case the preheader is
         {                                        // executed in its first iteration and is protected.
         if (performTransformation(comp(), "%sMove out loop-invariant node [%p] to block_%d\n", OPT_DETAILS, node, preheaderBlock->getNumber()))
            {
            if (!(removeOnly))
               {
               TR::Node *newNode = node->duplicateTree();
               if (replaceWithNewNode)
                  newNode->getFirstChild()->setAndIncChild(expChildNumber, expNode);
               transformNode(newNode, preheaderBlock);
               }
            TR::TransformUtil::removeTree(comp(), treeTop);
            }
         }
      }
      return (expNode != NULL);
   }
Ejemplo n.º 24
0
void TR_ExpressionsSimplification::simplifyInvariantLoopExpressions(ListIterator<TR::Block> &blocks)
   {
   // Need to locate the induction variable of the loop
   //
   LoopInfo *loopInfo = findLoopInfo(_currentRegion);

   if (trace())
      {
      if (!loopInfo)
         {
         traceMsg(comp(), "Accurate loop info is not found, cannot carry out summation reduction\n");
         }
      else
         {
         traceMsg(comp(), "Accurate loop info has been found, will try to carry out summation reduction\n");
         if (loopInfo->getBoundaryNode())
            {
            traceMsg(comp(), "Variable iterations from node %p has not been handled\n",loopInfo->getBoundaryNode());
            }
         else
            {
            traceMsg(comp(), "Natural Loop %p will run %d times\n", _currentRegion, loopInfo->getNumIterations());
            }
         }
      }

   // Initialize the list of candidates
   //
   _candidateTTs = new (trStackMemory()) TR_ScratchList<TR::TreeTop>(trMemory());

   for (TR::Block *currentBlock = blocks.getFirst(); currentBlock; currentBlock  = blocks.getNext())
      {
      if (trace())
         traceMsg(comp(), "Analyzing block #%d, which must be executed once per iteration\n", currentBlock->getNumber());


      // Scan through each node in the block
      //
      TR::TreeTop *tt = currentBlock->getEntry();
      TR::TreeTop *exitTreeTop = currentBlock->getExit();
      while (tt != exitTreeTop)
         {
         TR::Node *currentNode = tt->getNode();
         if (trace())
            traceMsg(comp(), "Analyzing tree top node %p\n", currentNode);

         if (loopInfo)
            {
            // requires loop info for the number of iterations
            setSummationReductionCandidates(currentNode, tt);
            }
         setStoreMotionCandidates(currentNode, tt);

         tt = tt->getNextTreeTop();
         }
      }

   // New code: without using any UDI
   // walk through the trees in the loop
   // to invalidate the candidates
   //
   if (!_supportedExpressions)
      {
      _supportedExpressions = new (trStackMemory()) TR_BitVector(comp()->getNodeCount(), trMemory(), stackAlloc, growable);
      }

   invalidateCandidates();

   ListIterator<TR::TreeTop> treeTops(_candidateTTs);
   for (TR::TreeTop *treeTop = treeTops.getFirst(); treeTop; treeTop = treeTops.getNext())
      {
      if (trace())
         traceMsg(comp(), "Candidate TreeTop: %p, Node:%p\n", treeTop, treeTop->getNode());

      bool usedCandidate = false;
      bool isPreheaderBlockInvalid = false;

      if (loopInfo)
         {
         usedCandidate = tranformSummationReductionCandidate(treeTop, loopInfo, &isPreheaderBlockInvalid);
         }

      if (isPreheaderBlockInvalid)
         {
         break;
         }

      if (!usedCandidate)
         {
         tranformStoreMotionCandidate(treeTop, &isPreheaderBlockInvalid);
         }
      if (isPreheaderBlockInvalid)
         {
         break;
         }
      }
   }
Ejemplo n.º 25
0
TR_ExpressionsSimplification::LoopInfo*
TR_ExpressionsSimplification::findLoopInfo(TR_RegionStructure* region)
   {
   ListIterator<TR::CFGEdge> exitEdges(&region->getExitEdges());

   if (region->getExitEdges().getSize() != 1)
      {
      if (trace())
         traceMsg(comp(), "Region with more than 1 exit edges can't be handled\n");
      return 0;
      }

   TR_StructureSubGraphNode* exitNode = toStructureSubGraphNode(exitEdges.getFirst()->getFrom());

   if (!exitNode->getStructure()->asBlock())
      {
      if (trace())
         traceMsg(comp(), "The exit block can't be found\n");
      return 0;
      }

   TR::Block *exitBlock = exitNode->getStructure()->asBlock()->getBlock();
   TR::Node *lastTreeInExitBlock = exitBlock->getLastRealTreeTop()->getNode();

   if (trace())
      {
      traceMsg(comp(), "The exit block is %d\n", exitBlock->getNumber());
      traceMsg(comp(), "The branch node is %p\n", lastTreeInExitBlock);
      }


   if (!lastTreeInExitBlock->getOpCode().isBranch())
      {
      if (trace())
         traceMsg(comp(), "The branch node couldn't be found\n");
      return 0;
      }

   if (lastTreeInExitBlock->getNumChildren() < 2)
      {
      if (trace())
         traceMsg(comp(), "The branch node has less than 2 children\n");
      return 0;
      }

   TR::Node *firstChildOfLastTree = lastTreeInExitBlock->getFirstChild();
   TR::Node *secondChildOfLastTree = lastTreeInExitBlock->getSecondChild();

   if (!firstChildOfLastTree->getOpCode().hasSymbolReference())
      {
      if (trace())
         traceMsg(comp(), "The branch node's first child node %p - its opcode does not have a symbol reference\n", firstChildOfLastTree);
      return 0;
      }

   TR::SymbolReference *firstChildSymRef = firstChildOfLastTree->getSymbolReference();

   if (trace())
      traceMsg(comp(), "Symbol Reference: %p Symbol: %p\n", firstChildSymRef, firstChildSymRef->getSymbol());

   // Locate the induction variable that matches with the exit node symbol
   //
   TR_InductionVariable *indVar = region->findMatchingIV(firstChildSymRef);
   if (!indVar) return 0;

   if (!indVar->getIncr()->asIntConst())
      {
      if (trace())
         traceMsg(comp(), "Increment is not a constant\n");
      return 0;
      }

   int32_t increment = indVar->getIncr()->getLowInt();

   _visitCount = comp()->incVisitCount();
   bool indVarWrittenAndUsedUnexpectedly = false;
   if (firstChildOfLastTree->getReferenceCount() > 1)
      {
      TR::TreeTop *cursorTreeTopInExitBlock = exitBlock->getEntry();
      TR::TreeTop *exitTreeTopInExitBlock = exitBlock->getExit();

      bool loadSeen = false;
      while (cursorTreeTopInExitBlock != exitTreeTopInExitBlock)
         {
         TR::Node *cursorNode = cursorTreeTopInExitBlock->getNode();
         if (checkForLoad(cursorNode, firstChildOfLastTree))
            loadSeen = true;

         if (!cursorNode->getOpCode().isStore() &&
             (cursorNode->getNumChildren() > 0))
           cursorNode = cursorNode->getFirstChild();

         if (cursorNode->getOpCode().isStore() &&
             (cursorNode->getSymbolReference() == firstChildSymRef))
            {
            indVarWrittenAndUsedUnexpectedly = true;
            if ((cursorNode->getFirstChild() == firstChildOfLastTree) ||
                !loadSeen)
               indVarWrittenAndUsedUnexpectedly = false;
            else
               break;
            }

         cursorTreeTopInExitBlock = cursorTreeTopInExitBlock->getNextTreeTop();
         }
      }

   if (indVarWrittenAndUsedUnexpectedly)
      {
      return 0;
      }

   int32_t lowerBound;
   int32_t upperBound = 0;
   TR::Node *bound = 0;
   bool equals = false;

   switch(lastTreeInExitBlock->getOpCodeValue())
      {
      case TR::ificmplt:
      case TR::ificmpgt:
         equals = true;
      case TR::ificmple:
      case TR::ificmpge:
         if (!(indVar->getEntry() && indVar->getEntry()->asIntConst()))
            {
            if (trace())
               traceMsg(comp(), "Entry value is not a constant\n");
            return 0;
            }
         lowerBound = indVar->getEntry()->getLowInt();

         if (secondChildOfLastTree->getOpCode().isLoadConst())
            {
            upperBound = secondChildOfLastTree->getInt();
            }
         else if (secondChildOfLastTree->getOpCode().isLoadVar())
            {
            bound = secondChildOfLastTree;
            }
         else
            {
            if (trace())
               traceMsg(comp(), "Second child is not a const or a load\n");
            return 0;
            }
         return new (trStackMemory()) LoopInfo(bound, lowerBound, upperBound, increment, equals);


      default:
         if (trace())
            traceMsg(comp(), "The condition has not been implemeted\n");
         return 0;
      }

   return 0;
   }
Ejemplo n.º 26
0
void
OMR::CodeGenPhase::performSetupForInstructionSelectionPhase(TR::CodeGenerator * cg, TR::CodeGenPhase * phase)
   {
   TR::Compilation *comp = cg->comp();

   if (TR::Compiler->target.cpu.isZ() && TR::Compiler->om.shouldGenerateReadBarriersForFieldLoads())
      {
      // TODO (GuardedStorage): We need to come up with a better solution than anchoring aloadi's
      // to enforce certain evaluation order
      traceMsg(comp, "GuardedStorage: in performSetupForInstructionSelectionPhase\n");

      auto mapAllocator = getTypedAllocator<std::pair<TR::TreeTop*, TR::TreeTop*> >(comp->allocator());

      std::map<TR::TreeTop*, TR::TreeTop*, std::less<TR::TreeTop*>, TR::typed_allocator<std::pair<TR::TreeTop* const, TR::TreeTop*>, TR::Allocator> >
         currentTreeTopToappendTreeTop(std::less<TR::TreeTop*> (), mapAllocator);

      TR_BitVector *unAnchorableAloadiNodes = comp->getBitVectorPool().get();

      for (TR::PreorderNodeIterator iter(comp->getStartTree(), comp); iter != NULL; ++iter)
         {
         TR::Node *node = iter.currentNode();

         traceMsg(comp, "GuardedStorage: Examining node = %p\n", node);

         // isNullCheck handles both TR::NULLCHK and TR::ResolveAndNULLCHK
         // both of which do not operate on their child but their
         // grandchild (or greatgrandchild).
         if (node->getOpCode().isNullCheck())
            {
            // An aloadi cannot be anchored if there is a Null Check on
            // its child. There are two situations where this occurs.
            // The first is when doing an aloadi off some node that is
            // being NULLCHK'd (see Ex1). The second is when doing an
            // icalli in which case the aloadi loads the VFT of an
            // object that must be NULLCHK'd (see Ex2).
            //
            // Ex1:
            //    n1n NULLCHK on n3n
            //    n2n    aloadi f    <-- First Child And Parent of Null Chk'd Node
            //    n3n       aload O
            //
            // Ex2:
            //    n1n NULLCHK on n4n
            //    n2n    icall foo        <-- First Child
            //    n3n       aloadi <vft>  <-- Parent of Null Chk'd Node
            //    n4n          aload O
            //    n4n       ==> aload O

            TR::Node *nodeBeingNullChkd = node->getNullCheckReference();
            if (nodeBeingNullChkd)
               {
               TR::Node *firstChild = node->getFirstChild();
               TR::Node *parentOfNullChkdNode = NULL;

               if (firstChild->getOpCode().isCall() &&
                   firstChild->getOpCode().isIndirect())
                  {
                  parentOfNullChkdNode = firstChild->getFirstChild();
                  }
               else
                  {
                  parentOfNullChkdNode = firstChild;
                  }

               if (parentOfNullChkdNode &&
                   parentOfNullChkdNode->getOpCodeValue() == TR::aloadi &&
                   parentOfNullChkdNode->getNumChildren() > 0 &&
                   parentOfNullChkdNode->getFirstChild() == nodeBeingNullChkd)
                  {
                  unAnchorableAloadiNodes->set(parentOfNullChkdNode->getGlobalIndex());
                  traceMsg(comp, "GuardedStorage: Cannot anchor  %p\n", firstChild);
                  }
               }
            }
         else
            {
            bool shouldAnchorNode = false;

            if (node->getOpCodeValue() == TR::aloadi &&
                !unAnchorableAloadiNodes->isSet(node->getGlobalIndex()))
               {
               shouldAnchorNode = true;
               }
            else if (node->getOpCodeValue() == TR::aload &&
                     node->getSymbol()->isStatic() &&
                     node->getSymbol()->isCollectedReference())
               {
               shouldAnchorNode = true;
               }

            if (shouldAnchorNode)
               {
               TR::TreeTop* anchorTreeTop = TR::TreeTop::create(comp, TR::Node::create(TR::treetop, 1, node));
               TR::TreeTop* appendTreeTop = iter.currentTree();

               if (currentTreeTopToappendTreeTop.count(appendTreeTop) > 0)
                  {
                  appendTreeTop = currentTreeTopToappendTreeTop[appendTreeTop];
                  }

               // Anchor the aload/aloadi before the current treetop
               appendTreeTop->insertBefore(anchorTreeTop);
               currentTreeTopToappendTreeTop[iter.currentTree()] = anchorTreeTop;

               traceMsg(comp, "GuardedStorage: Anchored  %p to treetop = %p\n", node, anchorTreeTop);
               }
            }
         }

      comp->getBitVectorPool().release(unAnchorableAloadiNodes);
      }

   if (cg->shouldBuildStructure() &&
       (comp->getFlowGraph()->getStructure() != NULL))
      {
      TR_Structure *rootStructure = TR_RegionAnalysis::getRegions(comp);
      comp->getFlowGraph()->setStructure(rootStructure);
      }

   phase->reportPhase(SetupForInstructionSelectionPhase);

   // Dump preIR
   if (comp->getOption(TR_TraceRegisterPressureDetails) && !comp->getOption(TR_DisableRegisterPressureSimulation))
      {
      traceMsg(comp, "         { Post optimization register pressure simulation\n");
      TR_BitVector emptyBitVector;
      vcount_t vc = comp->incVisitCount();
      cg->initializeRegisterPressureSimulator();
      for (TR::Block *block = comp->getStartBlock(); block; block = block->getNextExtendedBlock())
         {
         TR_LinkHead<TR_RegisterCandidate> emptyCandidateList;
         TR::CodeGenerator::TR_RegisterPressureState state(NULL, 0, emptyBitVector, emptyBitVector, &emptyCandidateList, cg->getNumberOfGlobalGPRs(), cg->getNumberOfGlobalFPRs(), cg->getNumberOfGlobalVRFs(), vc);
         TR::CodeGenerator::TR_RegisterPressureSummary summary(state._gprPressure, state._fprPressure, state._vrfPressure);
         cg->simulateBlockEvaluation(block, &state, &summary);
         }
      traceMsg(comp, "         }\n");
      }

   TR::LexicalMemProfiler mp(phase->getName(), comp->phaseMemProfiler());
   LexicalTimer pt(phase->getName(), comp->phaseTimer());

   cg->setUpForInstructionSelection();
   }
Ejemplo n.º 27
0
// This opt tries to reduce merge backs from cold code that are the result of inliner
// gnerated nopable virtual guards
// It looks for one basic pattern
//
// guard1 -> cold1
// BBEND
// BBSTART
// guard2 -> cold2
// if guard1 is the guard for a method which calls the method guard2 protects or cold1 is
// a predecessor of cold2 (a situation commonly greated by virtual guard tail splitter) we
// can transform the guards as follows when guard1 and guard2 a
// guard1 -> cold1
// BBEND
// BBSTART
// guard2 -> cold1
// This is safe because there are no trees between the guards and calling the caller will
// result in the call to the callee if we need to patch guard2. cold2 and its mergebacks
// can then be eliminated
//
// In addition this opt will try to move guard2 up from the end of a block to the
// start of the block. We can do this if guard2 is an HCR guard and there is no GC point
// between BBSTART and guard2 since HCR is a stop-the-world event.
//
// Finally, there is a simple tail splitting step run before the analysis of a guard if we
// detect that the taken side of the guard merges back in the next block - this happens
// for some empty methods and is common for Object.<init> at the top of constructors.
int32_t TR_VirtualGuardHeadMerger::perform() {
   static char *disableVGHeadMergerTailSplitting = feGetEnv("TR_DisableVGHeadMergerTailSplitting");
   TR::CFG *cfg = comp()->getFlowGraph();

   // Cache the loads for the outer guard's cold path
   TR_BitVector coldPathLoads(comp()->trMemory()->currentStackRegion());
   TR_BitVector privArgSymRefs(comp()->trMemory()->currentStackRegion());
   bool evaluatedColdPathLoads = false;

   for (TR::Block *block = optimizer()->getMethodSymbol()->getFirstTreeTop()->getNode()->getBlock();
        block; block = block->getNextBlock())
      {
      TR::Node *guard1 = block->getLastRealTreeTop()->getNode();

      if (isMergeableGuard(guard1))
         {
         if (trace())
            traceMsg(comp(), "Found mergeable guard in block_%d\n", block->getNumber());
         TR::Block *cold1 = guard1->getBranchDestination()->getEnclosingBlock();

         // check for an immediate merge back from the cold block and
         // tail split one block if we can - we only handle splitting a block
         // ending in a fallthrough, a branch or a goto for now for simplicity
         if (!disableVGHeadMergerTailSplitting &&
             (cold1->getSuccessors().size() == 1) &&
             cold1->hasSuccessor(block->getNextBlock()) &&
             cold1->getLastRealTreeTop()->getNode()->getOpCode().isGoto())
            {
            // TODO handle moving code earlier in the block down below the guard
            // tail split
            if ((block->getNextBlock()->getSuccessors().size() == 1) ||
                ((block->getNextBlock()->getSuccessors().size() == 2) &&
                 block->getNextBlock()->getLastRealTreeTop()->getNode()->getOpCode().isBranch()) &&
                performTransformation(comp(), "%sCloning block_%d and placing clone after block_%d to reduce HCR guard nops\n", OPT_DETAILS, block->getNextBlock()->getNumber(), cold1->getNumber()))
               tailSplitBlock(block, cold1);
            }

         // guard motion is fairly complex but what we want to achieve around guard1 is a sequence
         // of relocated privarg blocks, followed by a sequence of runtime patchable guards going to
         // guard1's cold block, followed by a sequence of stop-the-world guards going to guard1's
         // cold block
         //
         // The following code is to setup the various insert points based on the following diagrams
         // of basic blocks:
         //
         // start:               setup:                          end result after moving runtime guard'
         //                       |       |                        +-------+ <-- privargIns
         //                       |       | <-- privargIns             |
         //                       +-------+ <-- runtimeIns         +-------+
         //   |       |               |                            | Guard'|
         //   |       |               V                            +-------+ <-- runtimeIns
         //   +-------+           +-------+                            |
         //   | Guard |           | Guard |                            V
         //   +-------+           +-------+ <-- HCRIns             +-------+
         //       |        ===>       |                    ===>    | Guard |
         //       V                   V                            +-------+ <-- HCRIns
         //   +-------+           +-------+                            |
         //   |       |           |       |                            V
         //   |       |           |       |                        +-------+
         //
         // Note we always split the block - this may create an empty block but preserves the incoming
         // control flow we leave the rest to block extension to fix later

         block = block->split(block->getLastRealTreeTop(), cfg, true, false);
         TR::Block *privargIns = block->getPrevBlock();
         TR::Block *runtimeIns = block->getPrevBlock();
         TR::Block *HCRIns = block;

         // New outer guard so cold paths must be evaluated
         evaluatedColdPathLoads = false;

         // scan for candidate guards to merge with guard1 identified above
         for (TR::Block *nextBlock = block->getNextBlock(); nextBlock; nextBlock = nextBlock->getNextBlock())
            {
            if (!(nextBlock->getPredecessors().size() == 1) ||
                !nextBlock->hasPredecessor(block))
               {
               break;
               }

            TR::TreeTop *guard2Tree = NULL;
            if (isMergeableGuard(nextBlock->getFirstRealTreeTop()->getNode()))
               {
               guard2Tree = nextBlock->getFirstRealTreeTop();
               }
            else if (isMergeableGuard(nextBlock->getLastRealTreeTop()->getNode()))
               {
               guard2Tree = nextBlock->getLastRealTreeTop();
               }
            else
               break;

            TR::Node *guard2 = guard2Tree->getNode();
            TR::Block *guard2Block = nextBlock;

            // It is not possible to shift an OSR guard unless the destination is already an OSR point
            // as the necessary OSR state will not be available
            if (guard2->isOSRGuard() && !guard1->isOSRGuard())
               break;

            TR::Block *insertPoint = isStopTheWorldGuard(guard2) ? HCRIns : runtimeIns;
            if (!safeToMoveGuard(insertPoint, guard2Tree, guard1->getBranchDestination(), privArgSymRefs))
               break;

            // now we figure out if we can redirect guard2 to guard1's cold block
            // ie can we do the head merge
            TR::Block *cold2 = guard2->getBranchDestination()->getEnclosingBlock();
            if (guard1->getInlinedSiteIndex() == guard2->getInlinedSiteIndex())
               {
               if (trace())
                  traceMsg(comp(), "  Guard1 [%p] is guarding the same call as Guard2 [%p] - proceeding with guard merging\n", guard1, guard2);
               }
            else if (guard2->getInlinedSiteIndex() > -1 &&
                guard1->getInlinedSiteIndex() == TR::comp()->getInlinedCallSite(guard2->getInlinedSiteIndex())._byteCodeInfo.getCallerIndex())
               {
               if (trace())
                  traceMsg(comp(), "  Guard1 [%p] is the caller of Guard2 [%p] - proceeding with guard merging\n", guard1, guard2);
               }
            else if ((cold1->getSuccessors().size() == 1) &&
                     cold1->hasSuccessor(cold2))
               {
               if (trace())
                  traceMsg(comp(), "  Guard1 cold destination block_%d has guard2 cold destination block_%d as its only successor - proceeding with guard merging\n", cold1->getNumber(), cold2->getNumber());
               }
            else
               {
               if (trace())
                  traceMsg(comp(), "  Cold1 block_%d and cold2 block_%d of guard2 [%p] in unknown relationship - abandon the merge attempt\n", cold1->getNumber(), cold2->getNumber(), guard2);
               break;
               }

            // Runtime guards will shift their privargs, so it is necessary to check such a move is safe
            // This is possible if a privarg temp was recycled for the inner call site, with a prior use as an
            // argument for the outer call site. As the privargs for the inner call site must be evaluated before
            // both guards, this would result in the recycled temp holding the incorrect value if the guard is ever
            // taken.
            if (!isStopTheWorldGuard(guard2))
               {
               if (!evaluatedColdPathLoads)
                  {
                  collectColdPathLoads(cold1, coldPathLoads);
                  evaluatedColdPathLoads = true;
                  }

               if (coldPathLoads.intersects(privArgSymRefs))
                  {
                  if (trace())
                     traceMsg(comp(), "  Recycled temp live in cold1 block_%d and used as privarg before guard2 [%p] - stop guard merging", cold1->getNumber(), guard2);
                  break;
                  }
               }

            if (!performTransformation(comp(), "%sRedirecting %s guard [%p] in block_%d to parent guard cold block_%d\n", OPT_DETAILS, isStopTheWorldGuard(guard2) ? "stop the world" : "runtime", guard2, guard2Block->getNumber(), cold1->getNumber()))
                  continue;

            if (guard2->getBranchDestination() != guard1->getBranchDestination())
               guard2Block->changeBranchDestination(guard1->getBranchDestination(), cfg);

            if (guard2Tree != guard2Block->getFirstRealTreeTop())
               {
               cfg->setStructure(NULL);

               // We should leave code ahead of an HCR guard in place because:
               // 1, it might have side effect to runtime guards after it, moving it up might cause us to falsely merge
               //    the subsequent runtime guards
               // 2, it might contain live monitor, moving it up above a guard can affect the monitor's live range
               if (!isStopTheWorldGuard(guard2))
                  {
	          // the block created above guard2 contains only privarg treetops or monitor stores if
                  // guard2 is a runtime-patchable guard and is safe to merge. We need to move the priv
                  // args up to the runtime insert point and leave the monitor stores in place
                  // It's safe to do so because there is no data dependency between the monitor store and
                  // the priv arg store, because the priv arg store does not load the value from the temp
                  // holding the monitored object

                  // Split priv arg stores from monitor stores
                  // Monitor store is generated for the caller of the method guard2 protects, so should appear before
                  // priv arg stores for the method guard2 protects
                  TR::Block *privargBlock = guard2Block;
                  guard2Block = splitRuntimeGuardBlock(comp(), guard2Block, cfg);
                  if (privargBlock != guard2Block)
                     {
                     if (trace())
                        traceMsg(comp(), "  Moving privarg block_%d after block_%d\n", privargBlock->getNumber(), privargIns->getNumber());

                     moveBlockAfterDest(cfg, privargBlock, privargIns);

                     if (HCRIns == privargIns)
                        HCRIns = privargBlock;
                     if (runtimeIns == privargIns)
                        runtimeIns = privargBlock;
                     privargIns = privargBlock;

                     // refresh the insertPoint since it could be stale after the above updates
                     insertPoint = runtimeIns;
                     }
                  }

               guard2Block = guard2Block->split(guard2Tree, cfg, true, false);
               if (trace())
                  traceMsg(comp(), "  Created new block_%d to hold guard [%p] from block_%d\n", guard2Block->getNumber(), guard2, guard2Block->getNumber());
               }

            if (insertPoint != guard2Block->getPrevBlock())
               {
               TR::DebugCounter::incStaticDebugCounter(comp(), TR::DebugCounter::debugCounterName(comp(), "headMerger/%s_%s/(%s)", isStopTheWorldGuard(guard1) ? "stop the world" : "runtime", isStopTheWorldGuard(guard2) ? "stop the world" : "runtime", comp()->signature()));
               cfg->setStructure(NULL);

               block = nextBlock = guard2Block->getPrevBlock();
               if (trace())
                  traceMsg(comp(), "  Moving guard2 block block_%d after block_%d\n", guard2Block->getNumber(), insertPoint->getNumber());

               moveBlockAfterDest(cfg, guard2Block, insertPoint);

               if (HCRIns == insertPoint)
                  HCRIns = guard2Block;
               if (runtimeIns == insertPoint)
                  runtimeIns = guard2Block;
               }
            else
               {
               block = guard2Block;
               }
            guard1 = guard2;
            }
         }
      }
   return 1;
}
Ejemplo n.º 28
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;
   }
Ejemplo n.º 29
0
// This function splits a single succeesor block following an guard and is used to
// do the following transform
//    block - cold1         block - cold1
//      \     /        =>     |       |
//     nextBlock           nextBlock nextBlock' (called tailSplitBlock below)
//         |                  \      /
//        ...                   ...
void TR_VirtualGuardHeadMerger::tailSplitBlock(TR::Block * block, TR::Block * cold1)
   {
   TR::CFG *cfg = comp()->getFlowGraph();
   cfg->setStructure(NULL);
   TR_BlockCloner cloner(cfg);
   TR::Block *tailSplitBlock = cloner.cloneBlocks(block->getNextBlock(), block->getNextBlock());
   tailSplitBlock->setFrequency(cold1->getFrequency());
   if (cold1->isCold())
      tailSplitBlock->setIsCold();

   // physically put the block after cold1 since we want cold1 to fall through
   tailSplitBlock->getExit()->join(cold1->getExit()->getNextTreeTop());
   cold1->getExit()->join(tailSplitBlock->getEntry());

   // remove cold1's goto
   TR::TransformUtil::removeTree(comp(), cold1->getExit()->getPrevRealTreeTop());

   // copy the exception edges
   for (auto e = block->getNextBlock()->getExceptionSuccessors().begin(); e != block->getNextBlock()->getExceptionSuccessors().end(); ++e)
      cfg->addExceptionEdge(tailSplitBlock, (*e)->getTo());

   cfg->addEdge(cold1, tailSplitBlock);
   // lastly fix up the exit of tailSplitBlock
   TR::Node *tailSplitEnd = tailSplitBlock->getExit()->getPrevRealTreeTop()->getNode();
   if (tailSplitEnd->getOpCode().isGoto())
      {
      tailSplitEnd->setBranchDestination(block->getNextBlock()->getLastRealTreeTop()->getNode()->getBranchDestination());
      cfg->addEdge(tailSplitBlock, block->getNextBlock()->getSuccessors().front()->getTo());
      }
   else if (tailSplitEnd->getOpCode().isBranch())
      {
      TR::Block *gotoBlock = TR::Block::createEmptyBlock(tailSplitEnd, comp(), cold1->getFrequency());
      if (cold1->isCold())
          gotoBlock->setIsCold(true);
      gotoBlock->getExit()->join(tailSplitBlock->getExit()->getNextTreeTop());
      tailSplitBlock->getExit()->join(gotoBlock->getEntry());
      cfg->addNode(gotoBlock);

      gotoBlock->append(TR::TreeTop::create(comp(), TR::Node::create(tailSplitEnd, TR::Goto, 0, block->getNextBlock()->getExit()->getNextTreeTop())));
      cfg->addEdge(tailSplitBlock, gotoBlock);
      cfg->addEdge(tailSplitBlock, tailSplitBlock->getLastRealTreeTop()->getNode()->getBranchDestination()->getEnclosingBlock());
      cfg->addEdge(gotoBlock, block->getNextBlock()->getNextBlock());
      }
   else if (
            !tailSplitEnd->getOpCode().isReturn() &&
            !tailSplitEnd->getOpCode().isJumpWithMultipleTargets() &&
             tailSplitEnd->getOpCodeValue() != TR::athrow &&
            !(tailSplitEnd->getNumChildren() >= 1 && tailSplitEnd->getFirstChild()->getOpCodeValue() == TR::athrow)
           )
      {
      tailSplitBlock->append(TR::TreeTop::create(comp(), TR::Node::create(tailSplitEnd, TR::Goto, 0, block->getNextBlock()->getExit()->getNextTreeTop())));
      cfg->addEdge(tailSplitBlock, block->getNextBlock()->getNextBlock());
      }
   else
      {
      for (auto e = block->getNextBlock()->getSuccessors().begin(); e != block->getNextBlock()->getSuccessors().end(); ++e)
         cfg->addEdge(tailSplitBlock, (*e)->getTo());
      }
   cfg->removeEdge(cold1, block->getNextBlock());

   optimizer()->setUseDefInfo(NULL);
   optimizer()->setValueNumberInfo(NULL);
   }