Ejemplo n.º 1
0
//---------------------------------------------------------------------
// Common routine to change a conditional branch into an unconditional one.
// Change the node to be the unconditional branch or NULL if no branch taken.
// Return true if blocks were removed as a result of the change
//
bool
OMR::Simplifier::conditionalToUnconditional(TR::Node *&node, TR::Block * block, int takeBranch)
   {
   if (!performTransformation(comp(), "%s change conditional to unconditional n%in\n",
         optDetailString(), node->getNodePoolIndex()))
      {
      return false;
      }

   TR::CFGEdge* removedEdge = changeConditionalToUnconditional(node, block, takeBranch, _curTree, optDetailString());
   bool blocksWereRemoved = removedEdge ? removedEdge->getTo()->nodeIsRemoved() : false;


   if (takeBranch)
      {
      TR_ASSERT(node->getOpCodeValue() == TR::Goto, "expecting the node to have been converted to a goto");
      node = simplify(node, block);
      }

   if (blocksWereRemoved)
      {
      _invalidateUseDefInfo = true;
      _alteredBlock = true;
      _blockRemoved = true;
      }
   return blocksWereRemoved;
   }
Ejemplo n.º 2
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 3
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
   }