Earliestness.cpp

/*******************************************************************************
 * Copyright IBM Corp. and others 2000
 *
 * This program and the accompanying materials are made available under
 * the terms of the Eclipse Public License 2.0 which accompanies this
 * distribution and is available at https://www.eclipse.org/legal/epl-2.0/
 * or the Apache License, Version 2.0 which accompanies this distribution
 * and is available at https://www.apache.org/licenses/LICENSE-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License, v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception [1] and GNU General Public
 * License, version 2 with the OpenJDK Assembly Exception [2].
 *
 * [1] https://www.gnu.org/software/classpath/license.html
 * [2] https://openjdk.org/legal/assembly-exception.html
 *
 * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0 OR GPL-2.0-only WITH OpenJDK-assembly-exception-1.0
 *******************************************************************************/

#include <stddef.h>
#include <stdint.h>
#include "compile/Compilation.hpp"
#include "env/TRMemory.hpp"
#include "il/Block.hpp"
#include "il/Node.hpp"
#include "il/TreeTop.hpp"
#include "il/TreeTop_inlines.hpp"
#include "infra/BitVector.hpp"
#include "optimizer/Structure.hpp"
#include "optimizer/DataFlowAnalysis.hpp"
#include "optimizer/LocalAnalysis.hpp"

namespace TR { class Optimizer; }

// #define MAX_BLOCKS_FOR_STACK_ALLOCATION 16

// This file contains an implementation of Earliestness which
// is the second global bit vector analyses used by PRE. Earliestness
// attempts to discover for each expression, the earliest globally
// anticipatable point(s) in the CFG. This is the highest optimal point to
// which the computation of the expression can be moved. It is the optimal
// point as computed by Morel and Renvoise's PRE algorithm.
//
//
TR_DataFlowAnalysis::Kind TR_Earliestness::getKind()
   {
   return Earliestness;
   }

TR_Earliestness *TR_Earliestness::asEarliestness()
   {
   return this;
   }


int32_t TR_Earliestness::getNumberOfBits()
   {
   return _globalAnticipatability->_numberOfBits;
   }


void TR_Earliestness::analyzeNode(TR::Node *, vcount_t, TR_BlockStructure *, TR_BitVector *)
   {
   }



TR_Earliestness::TR_Earliestness(TR::Compilation *comp, TR::Optimizer *optimizer, TR_Structure *rootStructure, bool trace)
   : TR_UnionBitVectorAnalysis(comp, comp->getFlowGraph(), optimizer, trace)
   {
   _globalAnticipatability = new (comp->allocator()) TR_GlobalAnticipatability(comp, optimizer, rootStructure, trace);

   if (trace)
      traceMsg(comp, "Starting Earliestness\n");

   _supportedNodesAsArray = _globalAnticipatability->_supportedNodesAsArray;

   _temp = NULL;
   performAnalysis(rootStructure, false);
   if (trace)
      traceMsg(comp, "Earl # bits %d, %d\n", _numberOfBits, _globalAnticipatability->_numberOfBits);
   if (trace)
      {
      int32_t i;
      for (i = 0; i < _numberOfNodes; i++)
         {
         traceMsg(comp, "Block number : %d has solution : ", i);
         _inSetInfo[i]->print(comp);
         traceMsg(comp, "\n");
         }
      traceMsg(comp, "\nEnding Earliestness\n");
      }

   // Null out info not used by callers
   _blockAnalysisInfo = NULL;
   }

bool TR_Earliestness::postInitializationProcessing()
   {
   int32_t i;
   _inSetInfo = (ContainerType **)trMemory()->allocateStackMemory(_numberOfNodes*sizeof(ContainerType *));

   for (i = 0; i < _numberOfNodes; i++)
      allocateContainer(_inSetInfo + i);

   // Start Node has all bits set even though its a UnionBitVectorAnalysis
   //
   _currentInSetInfo->setAll(_numberOfBits);
   copyFromInto(_currentInSetInfo, _originalInSetInfo);
   return true;
   }


// Overrides the implementation in the superclass as this analysis
// is slightly different from conventional bit vector analyses.
// It uses the results from local analyses instead of examining
// each tree top for effects on the input bit vector at that tree top.
// This analysis has a trivial analyzeNode(...) method as a result.
//
//
void TR_Earliestness::analyzeTreeTopsInBlockStructure(TR_BlockStructure *blockStructure)
   {
   copyFromInto(_currentInSetInfo, _inSetInfo[blockStructure->getNumber()]);
   copyFromInto(_currentInSetInfo, _blockAnalysisInfo[blockStructure->getNumber()]);

   // Block info is local to this analysis, so allocate from there
   if (_temp == NULL)
      allocateBlockInfoContainer(&_temp);
   _temp->setAll(_numberOfBits);
   *_temp -= *(_globalAnticipatability->_blockAnalysisInfo[blockStructure->getNumber()]);
   *(_blockAnalysisInfo[blockStructure->getNumber()]) &= *_temp;

   _temp->setAll(_numberOfBits);
   *_temp -= *(_globalAnticipatability->_localTransparency.getAnalysisInfo(blockStructure->getBlock()->getNumber()));

   *(_blockAnalysisInfo[blockStructure->getNumber()]) |= *_temp;
   copyFromInto(_blockAnalysisInfo[blockStructure->getNumber()], _regularInfo);

   if (trace())
      {
      /////traceMsg(comp(), "\nIn Set of Block : %d\n", blockStructure->getNumber());
      /////_inSetInfo[blockStructure->getNumber()]->print(comp()->getOutFile());
      /////traceMsg(comp(), "\nOut Set of Block : %d\n", blockStructure->getNumber());
      /////_blockAnalysisInfo[blockStructure->getNumber()]->print(comp()->getOutFile());
      }

   TR::Block *block = blockStructure->getBlock();
   TR::TreeTop *currentTree = block->getEntry();
   TR::TreeTop *exitTree = block->getExit();
   bool notSeenTreeWithChecks = true;

   _containsExceptionTreeTop = false;
   while (!(currentTree == exitTree))
      {
      if (notSeenTreeWithChecks)
         {
         bool currentTreeHasChecks = treeHasChecks(currentTree);
         if (currentTreeHasChecks)
            {
            notSeenTreeWithChecks = false;
            _containsExceptionTreeTop = true;
            copyFromInto(_blockAnalysisInfo[blockStructure->getNumber()], _exceptionInfo);
            }
         }
      else
         break;

      if (!(currentTree == exitTree))
         currentTree = currentTree->getNextTreeTop();
      }

   getAnalysisInfo(blockStructure)->_containsExceptionTreeTop = _containsExceptionTreeTop;
   }