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OMRLocalCSE.cpp
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OMRLocalCSE.cpp
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/*******************************************************************************
* Copyright (c) 2000, 2020 IBM Corp. and others
*
* 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 http://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] http://openjdk.java.net/legal/assembly-exception.html
*
* SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0 WITH Classpath-exception-2.0 OR LicenseRef-GPL-2.0 WITH Assembly-exception
*******************************************************************************/
#include "optimizer/LocalCSE.hpp"
#include <stdlib.h>
#include <string.h>
#include "codegen/CodeGenerator.hpp"
#include "env/FrontEnd.hpp"
#include "compile/Compilation.hpp"
#include "compile/Method.hpp"
#include "compile/SymbolReferenceTable.hpp"
#include "control/Options.hpp"
#include "control/Options_inlines.hpp"
#include "cs2/arrayof.h"
#include "cs2/sparsrbit.h"
#include "env/IO.hpp"
#include "env/StackMemoryRegion.hpp"
#include "env/TRMemory.hpp"
#include "env/jittypes.h"
#include "il/AliasSetInterface.hpp"
#include "il/AutomaticSymbol.hpp"
#include "il/Block.hpp"
#include "il/DataTypes.hpp"
#include "il/ILOpCodes.hpp"
#include "il/ILOps.hpp"
#include "il/MethodSymbol.hpp"
#include "il/Node.hpp"
#include "il/Node_inlines.hpp"
#include "il/ResolvedMethodSymbol.hpp"
#include "il/Symbol.hpp"
#include "il/SymbolReference.hpp"
#include "il/TreeTop.hpp"
#include "il/TreeTop_inlines.hpp"
#include "infra/Assert.hpp"
#include "infra/BitVector.hpp"
#include "infra/List.hpp"
#include "infra/SimpleRegex.hpp"
#include "optimizer/Optimization.hpp"
#include "optimizer/Optimization_inlines.hpp"
#include "optimizer/OptimizationManager.hpp"
#include "optimizer/Optimizations.hpp"
#include "optimizer/Optimizer.hpp"
#include "ras/Debug.hpp"
#define MAX_DEPTH 3000
#define MAX_COPY_PROP 400
#define REPLACE_MARKER (MAX_SCOUNT-2)
#define NUM_BUCKETS 107
#define VOLATILE_ONLY 0
#define NON_VOLATILE_ONLY 1
#define VOLATILE_AND_NON_VOLATILE 2
OMR::LocalCSE::LocalCSE(TR::OptimizationManager *manager)
: TR::Optimization(manager),
_storeMap(NULL),
_arrayRefNodes(NULL)
{
static const char *e = feGetEnv("TR_loadaddrAsLoad");
_loadaddrAsLoad = e ? atoi(e) != 0 : 1;
}
TR::Optimization *OMR::LocalCSE::create(TR::OptimizationManager *manager)
{
return new (manager->allocator()) TR::LocalCSE(manager);
}
bool OMR::LocalCSE::shouldCopyPropagateNode(TR::Node *parent, TR::Node *node, int32_t childNum, TR::Node *storeNode)
{
int32_t childAdjust = storeNode->getOpCode().isWrtBar() ? 2 : 1;
int32_t maxChild = storeNode->getNumChildren() - childAdjust;
if (node->getNumChildren() < maxChild)
return false;
for (int32_t k = 0; k < maxChild; k++)
{
if (storeNode->getChild(k) != node->getChild(k))
return false;
}
if (_numCopyPropagations >= MAX_COPY_PROP)
{
if (trace())
traceMsg(comp(),"z^z : _numCopyPropagations %d >= max %d\n",_numCopyPropagations,MAX_COPY_PROP);
return false;
}
return true;
}
bool OMR::LocalCSE::shouldCommonNode(TR::Node *parent, TR::Node *node)
{
return isTreetopSafeToCommon();
}
TR::Node * getRHSOfStoreDefNode(TR::Node * storeNode)
{
int32_t childAdjust = (storeNode->getOpCode().isWrtBar()) ? 2 : 1;
int32_t maxChild = storeNode->getNumChildren() - childAdjust;
return storeNode->getChild(maxChild);
}
TR::Node *OMR::LocalCSE::getNode(TR::Node *node)
{
if (_volatileState != VOLATILE_ONLY)
return node;
if (_simulatedNodesAsArray[node->getGlobalIndex()])
{
TR::Node *toReturn = _simulatedNodesAsArray[node->getGlobalIndex()];
if (trace())
traceMsg(comp(), "Updating comparison node n%dn to n%dn due to volatile simulation\n", node->getGlobalIndex(), toReturn->getGlobalIndex());
return toReturn;
}
return node;
}
bool OMR::LocalCSE::doExtraPassForVolatiles()
{
if (TR::isJ9() && comp()->getMethodHotness() >= hot && !comp()->getOption(TR_DisableLocalCSEVolatileCommoning))
return true;
return false;
}
int32_t OMR::LocalCSE::perform()
{
if (trace())
traceMsg(comp(), "Starting LocalCommonSubexpressionElimination\n");
TR::Region &stackRegion = comp()->trMemory()->currentStackRegion();
_storeMap = new (stackRegion) StoreMap((StoreMapComparator()), StoreMapAllocator(stackRegion));
TR::TreeTop *tt, *exitTreeTop;
for (tt = comp()->getStartTree(); tt; tt = exitTreeTop->getNextTreeTop())
{
exitTreeTop = tt->getExtendedBlockExitTreeTop();
_volatileState = VOLATILE_AND_NON_VOLATILE;
if (doExtraPassForVolatiles())
{
if (trace())
traceMsg(comp(), "LocalCSE entering 2 pass mode for volatile elimination - pass 1 for volatiles ONLY\n");
_volatileState = VOLATILE_ONLY;
transformBlock(tt, exitTreeTop);
if (trace())
traceMsg(comp(), "LocalCSE volatile only pass 1 complete - pass 2 for non-volatiles ONLY\n");
_volatileState = NON_VOLATILE_ONLY;
transformBlock(tt, exitTreeTop);
}
else
transformBlock(tt, exitTreeTop);
}
if (trace())
traceMsg(comp(), "\nEnding LocalCommonSubexpressionElimination\n");
_storeMap = NULL;
return 1; // actual cost
}
int32_t OMR::LocalCSE::performOnBlock(TR::Block *block)
{
if (block->getEntry())
{
_volatileState = VOLATILE_AND_NON_VOLATILE;
if (doExtraPassForVolatiles())
{
if (trace())
traceMsg(comp(), "LocalCSE entering 2 pass mode for volatile elimination - pass 1 for volatiles ONLY\n");
_volatileState = VOLATILE_ONLY;
transformBlock(block->getEntry(), block->getEntry()->getExtendedBlockExitTreeTop());
if (trace())
traceMsg(comp(), "LocalCSE volatile only pass 1 complete - pass 2 for non-volatiles ONLY\n");
_volatileState = NON_VOLATILE_ONLY;
transformBlock(block->getEntry(), block->getEntry()->getExtendedBlockExitTreeTop());
}
else
transformBlock(block->getEntry(), block->getEntry()->getExtendedBlockExitTreeTop());
}
return 0;
}
void OMR::LocalCSE::prePerformOnBlocks()
{
TR::Region &stackRegion = comp()->trMemory()->currentStackRegion();
_storeMap = new (stackRegion) StoreMap((StoreMapComparator()), StoreMapAllocator(stackRegion));
int32_t symRefCount = 0;//comp()->getSymRefCount();
int32_t nodeCount = 0;//comp()->getNodeCount();
_seenCallSymbolReferences.init(symRefCount, stackRegion, growable);
_availableLoadExprs.init(symRefCount, stackRegion, growable);
_availablePinningArrayExprs.init(symRefCount, stackRegion, growable);
_availableCallExprs.init(symRefCount, stackRegion, growable);
_seenSymRefs.init(symRefCount, stackRegion, growable);
_possiblyRelevantNodes.init(symRefCount, stackRegion, growable);
_relevantNodes.init(symRefCount, stackRegion, growable);
_killedPinningArrayExprs.init(symRefCount, stackRegion, growable);
_killedNodes.init(nodeCount, stackRegion, growable);
_parentAddedToHT.init(nodeCount, stackRegion, growable);
comp()->incVisitCount();
_mayHaveRemovedChecks = false;
manager()->setAlteredCode(false);
_simulatedNodesAsArray = (TR::Node**)trMemory()->allocateStackMemory(comp()->getNodeCount()*sizeof(TR::Node*));
memset(_simulatedNodesAsArray, 0, comp()->getNodeCount()*sizeof(TR::Node*));
}
void OMR::LocalCSE::postPerformOnBlocks()
{
_storeMap = NULL;
if (_mayHaveRemovedChecks)
requestOpt(OMR::catchBlockRemoval);
}
bool
OMR::LocalCSE::isFirstReferenceToNode(TR::Node *parent, int32_t index, TR::Node *node, vcount_t visitCount)
{
return (visitCount > node->getVisitCount());
}
bool OMR::LocalCSE::shouldTransformBlock(TR::Block *block)
{
if (block->isCold())
return false;
return true;
}
void OMR::LocalCSE::transformBlock(TR::TreeTop * entryTree, TR::TreeTop * exitTree)
{
if (!shouldTransformBlock(entryTree->getNode()->getBlock()))
return;
// From here, down, stack memory allocations will die when the function returns
TR::StackMemoryRegion stackMemoryRegion(*trMemory());
TR::TreeTop *currentTree = entryTree;
int32_t numStores = 0, numNullChecks = 0;
_numNodes = 0;
_numNullCheckNodes = 0;
_numCopyPropagations = 0;
_arrayRefNodes = new (stackMemoryRegion) TR_ScratchList<TR::Node>(trMemory());
// Count the number of stores and null checks in this method; this is
// required to allocate data structures of the correct size. Null checks
// need to be counted separately as they are slightly different from other
// nodes in that equivalence of NULLCHKs is dictated by the null check
// reference rather than the entire subtree under the NULLCHK. Stores need
// to be counted separately as local copy propagation is done simultaneously
// along with local CSE. Also the total number of nodes are counted for
// allocating data structures for local commoning.
//
_possiblyRelevantNodes.empty();
_relevantNodes.empty();
_availableLoadExprs.empty();
_availablePinningArrayExprs.empty();
_killedPinningArrayExprs.empty();
_availableCallExprs.empty();
_parentAddedToHT.empty();
_killedNodes.empty();
// Visit counts are incremented multiple times while transforming a block.
// For each block, make sure there is enough room in the visit count to do this.
comp()->incOrResetVisitCount();
for (currentTree = entryTree->getNextRealTreeTop();
currentTree != exitTree->getNextTreeTop();
currentTree = currentTree->getNextRealTreeTop())
{
TR::Node *node = currentTree->getNode();
if (node->getStoreNode())
numStores++;
if (node->getOpCodeValue() == TR::NULLCHK)
numNullChecks++;
getNumberOfNodes(node);
}
_storeMap->clear();
_nullCheckNodesAsArray = (TR::Node**)trMemory()->allocateStackMemory(numNullChecks*sizeof(TR::Node*));
memset(_nullCheckNodesAsArray, 0, numNullChecks*sizeof(TR::Node*));
_replacedNodesAsArray = (TR::Node**)trMemory()->allocateStackMemory(_numNodes*sizeof(TR::Node*));
_replacedNodesByAsArray = (TR::Node**)trMemory()->allocateStackMemory(_numNodes*sizeof(TR::Node*));
memset(_replacedNodesAsArray, 0, _numNodes*sizeof(TR::Node*));
memset(_replacedNodesByAsArray, 0, _numNodes*sizeof(TR::Node*));
_hashTable = new (stackMemoryRegion) HashTable(std::less<int32_t>(), stackMemoryRegion);
_hashTableWithSyms = new (stackMemoryRegion) HashTable(std::less<int32_t>(), stackMemoryRegion);
_hashTableWithCalls = new (stackMemoryRegion) HashTable(std::less<int32_t>(), stackMemoryRegion);
_hashTableWithConsts = new (stackMemoryRegion) HashTable(std::less<int32_t>(), stackMemoryRegion);
_nextReplacedNode = 0;
TR_BitVector seenAvailableLoadedSymbolReferences(stackMemoryRegion);
_seenCallSymbolReferences.empty();
_seenSymRefs.empty();
int32_t nextNodeIndex = 0;
comp()->incVisitCount();
_curBlock = entryTree->getNode()->getBlock();
for (currentTree = entryTree->getNextRealTreeTop();
currentTree != exitTree->getNextTreeTop();
currentTree = currentTree->getNextRealTreeTop())
{
// set up new current treetop being examined and do any
// processing necessary on the treetop
onNewTreeTop(currentTree);
_canBeAvailable = true;
_isAvailableNullCheck = true;
_inSubTreeOfNullCheckReference = false;
_isTreeTopNullCheck = false;
TR::Node *currentNode = currentTree->getNode();
if (currentNode->getOpCodeValue() == TR::NULLCHK)
_isTreeTopNullCheck = true;
else if (currentNode->getOpCodeValue() == TR::BBStart)
_curBlock = currentNode->getBlock();
//
// This is the call to do local commoning and local copy propagation on this tree
//
bool nodeCanBeAvailable = true;
examineNode(currentNode, seenAvailableLoadedSymbolReferences, NULL, -1, &nextNodeIndex, &nodeCanBeAvailable, 0);
}
comp()->invalidateAliasRegion();
}
#ifdef J9_PROJECT_SPECIFIC
void
OMR::LocalCSE::setIsInMemoryCopyPropFlag(TR::Node *rhsOfStoreDefNode)
{
if (_treeBeingExamined &&
!rhsOfStoreDefNode->getOpCode().isLoadConst() &&
cg()->IsInMemoryType(rhsOfStoreDefNode->getType()))
{
if (cg()->traceBCDCodeGen() && _treeBeingExamined->getNode()->chkOpsIsInMemoryCopyProp() && !_treeBeingExamined->getNode()->isInMemoryCopyProp())
traceMsg(comp(),"\tset IsInMemoryCopyProp on %s (%p), rhsOfStoreDefNode %s (%p)\n",
_treeBeingExamined->getNode()->getOpCode().getName(),_treeBeingExamined->getNode(),rhsOfStoreDefNode->getOpCode().getName(),rhsOfStoreDefNode);
_treeBeingExamined->getNode()->setIsInMemoryCopyProp(true);
}
}
#endif
bool
OMR::LocalCSE::allowNodeTypes(TR::Node *storeNode, TR::Node *node)
{
if (storeNode->getDataType() == node->getDataType())
{
return true;
}
else if (storeNode->getType().isIntegral() && node->getType().isAggregate() &&
storeNode->getSize() == node->getSize())
{
return true;
}
return false;
}
/**
* Method examineNode
* ------------------
*
* This method performs local copy propagation and local common
* subexpression elimination on a given node.
*/
void OMR::LocalCSE::examineNode(TR::Node *node, TR_BitVector &seenAvailableLoadedSymbolReferences, TR::Node *parent, int32_t childNum, int32_t *nextLoadIndex, bool *parentCanBeAvailable, int32_t depth)
{
if (depth > MAX_DEPTH)
{
comp()->failCompilation<TR::ExcessiveComplexity>("scratch space in local CSE");
}
// If register pressure is high at this point, then nothing should be commoned or copy propagated across this point
// To achieve that, we clear all the commoning and copy propagation related information here
if (!canAffordToIncreaseRegisterPressure(node))
{
killAllDataStructures(seenAvailableLoadedSymbolReferences);
}
TR::ILOpCodes opCodeValue = node->getOpCodeValue();
bool nodeCanBeAvailable = true;
vcount_t visitCount = comp()->getVisitCount();
if (trace())
traceMsg(comp(), "Examining node %p\n",node);
if (!isFirstReferenceToNode(parent, childNum, node, visitCount))
{
if (trace())
traceMsg(comp(), "\tNot first Reference to Node\n");
doCommoningAgainIfPreviouslyCommoned(node, parent, childNum);
return;
}
TR::Node *nullCheckReference = NULL;
if (_isTreeTopNullCheck)
{
if (_treeBeingExamined->getNode()->getNullCheckReference() == node)
{
_inSubTreeOfNullCheckReference = true;
nullCheckReference = node;
}
}
for (int32_t i = 0 ; i < node->getNumChildren(); i++)
examineNode(node->getChild(i), seenAvailableLoadedSymbolReferences, node, i, nextLoadIndex, &nodeCanBeAvailable, depth+1);
node->setVisitCount(visitCount);
bool doneCopyPropagation = false;
bool doneCommoning = false;
// Note : Local copy propagation has been disabled for floats and doubles
// because of strict/non strict problems when a very large float/double value
// is stored and then read.
//
TR::SymbolReference * symRef = node->getOpCode().hasSymbolReference() ? node->getSymbolReference() : 0;
if (symRef && node->getOpCode().isLoadVar())
{
StoreMap::iterator result = _storeMap->find(symRef->getReferenceNumber());
if (result != _storeMap->end() && result->second->getSymbolReference()->getReferenceNumber() == symRef->getReferenceNumber())
{
// Base case: where symrefs match
doCopyPropagationIfPossible(node, parent, childNum, result->second, symRef, visitCount, doneCopyPropagation);
}
else if (node->getOpCode().isLoadIndirect() &&
node->getFirstChild()->getVisitCount() >= visitCount)
{
// Case #2: symrefs don't match, but underlying objects match by checking sizes, types, offsets, etc.
for (auto itr = _storeMap->begin(), end = _storeMap->end(); itr != end; ++itr)
{
TR::Node *storeNode = itr->second;
if (storeNode->getOpCode().isStoreIndirect() &&
storeNode->getSymbolReference()->getSymbol()->getSize() == symRef->getSymbol()->getSize() &&
storeNode->getSymbolReference()->getSymbol()->getDataType() == symRef->getSymbol()->getDataType() &&
allowNodeTypes(storeNode, node) &&
storeNode->getSymbolReference()->getOffset() == symRef->getOffset()
#ifdef J9_PROJECT_SPECIFIC
&& (!storeNode->getType().isBCD() ||
storeNode->getDecimalPrecision() == node->getDecimalPrecision())
#endif
)
{
if (doCopyPropagationIfPossible(node, parent, childNum, storeNode, symRef, visitCount, doneCopyPropagation))
break;
}
}
}
}
// This node has not been commoned up before; so examine it now.
// The checks below isAvailableNullCheck and canBeAvailable are really
// fast checks that might rule out the possibility of the expression (node) being
// available. Essentially we check if ALL symbols in the expression are
// available (this does not guarantee that the expression is available)
// but if any symbol is unavailable, then it is impossible for the node
// to be available.
//
if (!doneCopyPropagation &&
(((node->getOpCodeValue() == TR::NULLCHK) && (isAvailableNullCheck(node, seenAvailableLoadedSymbolReferences))) ||
(canBeAvailable(parent, node, seenAvailableLoadedSymbolReferences, nodeCanBeAvailable))
|| (!_loadaddrAsLoad && node->getOpCodeValue() == TR::loadaddr)))
{
doCommoningIfAvailable(node, parent, childNum, doneCommoning);
}
// Code below deals with how the availability and copy propagation
// information is updated once this node is seen
//
TR_UseDefAliasSetInterface UseDefAliases = node->mayKill(true);
bool hasAliases = !UseDefAliases.isZero(comp());
bool alreadyKilledAtVolatileLoad = false;
if (hasAliases && !doneCommoning)
alreadyKilledAtVolatileLoad = killExpressionsIfVolatileLoad(node, seenAvailableLoadedSymbolReferences, UseDefAliases);
// Step 1 : add this node to the data structures so that it can be considered for commoning
//
if (!(doneCommoning || doneCopyPropagation))
{
makeNodeAvailableForCommoning(parent, node, seenAvailableLoadedSymbolReferences, parentCanBeAvailable);
}
if (trace())
{
TR_BitVector tmpAliases(comp()->trMemory()->currentStackRegion());
traceMsg(comp(), "For Node %p UseDefAliases = ",node);
UseDefAliases.getAliasesAndUnionWith(tmpAliases);
tmpAliases.print(comp());
traceMsg(comp(), "\n");
}
// Step 2 : if this node is a potential kill point then update the fast and slow
// commoning and copy propagation info
//
if (node->getOpCode().isStore() || hasAliases)
{
// This node is a potential kill point
//
if (trace())
traceMsg(comp(), "\tnode %p isStore = %d or hasAliases = %d\n",node,node->getOpCode().isStore(),hasAliases);
int32_t symRefNum = node->getSymbolReference()->getReferenceNumber();
bool previouslyAvailable = false;
if (hasAliases)
{
//
// Kill slow copy propagation info
//
if (UseDefAliases.containsAny(_seenSymRefs, comp()))
{
int32_t storeNodesSize = static_cast<int32_t>(_storeMap->size());
// If we have over 500 store nodes, get aliases and iterate over the smaller set,
// Less than 500 nodes should not be too significant as to which set to iterate over.
if(storeNodesSize >= 500)
{
// Getting aliases can be very expensive if there are alot of aliases
// For this reason we don't always want to do this, only if storeNodes is large
// and we can make up the cost of getting aliases by iterating the smaller set
TR_BitVector tmpAliases(comp()->trMemory()->currentStackRegion());
UseDefAliases.getAliasesAndUnionWith(tmpAliases);
// Iterate over the smaller set to save compile time, this can be very significant
if (storeNodesSize < tmpAliases.elementCount())
{
for (auto itr = _storeMap->begin(), end = _storeMap->end(); itr != end; )
{
// Kill stores that are available for copy propagation based
// on this definition
TR::Node *storeNode = itr->second;
int32_t storeSymRefNum = storeNode->getSymbolReference()->getReferenceNumber();
if ((symRef->getReferenceNumber() == storeSymRefNum) || tmpAliases.get(storeSymRefNum))
{
_storeMap->erase(itr++);
}
else
++itr;
}
}
else
{
TR_BitVectorIterator bvi(tmpAliases);
while (bvi.hasMoreElements())
{
int32_t sc = bvi.getNextElement();
StoreMap::iterator result = _storeMap->find(sc);
if (result != _storeMap->end())
_storeMap->erase(sc);
}
}
}
else
{
for (auto itr = _storeMap->begin(), end = _storeMap->end(); itr != end; )
{
TR::Node *storeNode = itr->second;
int32_t storeSymRefNum = storeNode->getSymbolReference()->getReferenceNumber();
if ((symRef->getReferenceNumber() == storeSymRefNum) || UseDefAliases.contains(storeSymRefNum, comp()))
{
_storeMap->erase(itr++);
}
else
++itr;
}
}
}
// Kill fast commoning info
//
TR_BitVector tmp(seenAvailableLoadedSymbolReferences);
tmp -= _seenCallSymbolReferences;
if (trace())
{
traceMsg(comp(), "For node %p tmp: ",node);
tmp.print(comp());
traceMsg(comp(), "\n_seenCallSymbolReferences: ");
_seenCallSymbolReferences.print(comp());
traceMsg(comp(), "\n seenAvailableLoadedSymbolReferences:");
seenAvailableLoadedSymbolReferences.print(comp());
traceMsg(comp(), "\n");
}
if (UseDefAliases.containsAny(tmp, comp()))
{
// we want to keep the last load of a particular sym ref alive but no earlier loads should survive
// note that volatile processing already handles killing symbols when necessary hence the else
if (alreadyKilledAtVolatileLoad)
seenAvailableLoadedSymbolReferences.set(symRef->getReferenceNumber());
else
{
previouslyAvailable = true;
tmp = seenAvailableLoadedSymbolReferences;
tmp &= _seenCallSymbolReferences;
UseDefAliases.getAliasesAndSubtractFrom(seenAvailableLoadedSymbolReferences);
seenAvailableLoadedSymbolReferences |= tmp;
}
if (alreadyKilledAtVolatileLoad) // we want to keep the last load of a particular sym ref alive but no earlier loads should surivive
seenAvailableLoadedSymbolReferences.set(symRef->getReferenceNumber());
}
}
else
{
// There are no use def aliases
//
int32_t symRefNumber = symRef->getReferenceNumber();
// Kill slow copy propagation info
//
if (_seenSymRefs.get(symRefNumber))
{
for (auto itr = _storeMap->begin(), end = _storeMap->end(); itr != end; ++itr)
{
// Kill stores that are available for copy propagation based
// on this definition
TR::Node *storeNode = itr->second;
int32_t storeSymRefNum = storeNode->getSymbolReference()->getReferenceNumber();
if (symRefNumber == storeSymRefNum)
{
_storeMap->erase(itr++);
}
}
}
// Kill fast availability info for commoning
//
if (seenAvailableLoadedSymbolReferences.get(symRef->getReferenceNumber()))
previouslyAvailable = true;
seenAvailableLoadedSymbolReferences.reset(symRef->getReferenceNumber());
}
// Internal pointers should be killed if the pinning array was killed
//
if (symRef && symRef->getSymbol()->isAuto() &&
_availablePinningArrayExprs.get(symRef->getReferenceNumber()))
{
killAllInternalPointersBasedOnThisPinningArray(symRef);
}
// Only go into killing available expressions (i.e. slow availability info for commoning) if the symbol
// is available now; otherwise there is nothing to kill.
//
if (previouslyAvailable)
{
if (hasAliases)
killAvailableExpressionsUsingAliases(UseDefAliases);
if (node->getOpCode().isLikeDef())
killAvailableExpressions(symRefNum);
}
// Step 3 : add this node as a copy propagation candidate if it is a store
//
if (node->getOpCode().isStore())
{
(*_storeMap)[symRefNum] = node;
}
if (symRef && !node->getOpCode().isCall())
_seenSymRefs.set(symRef->getReferenceNumber());
}
killAvailableExpressionsAtGCSafePoints(node, parent, seenAvailableLoadedSymbolReferences);
if (_isTreeTopNullCheck)
{
if (nullCheckReference != NULL)
_inSubTreeOfNullCheckReference = false;
}
if (node->getOpCode().isCall())
{
seenAvailableLoadedSymbolReferences.set(node->getSymbolReference()->getReferenceNumber());
// pure calls can be commoned so we must observe kills
if (!node->isPureCall())
_seenCallSymbolReferences.set(node->getSymbolReference()->getReferenceNumber());
}
static char *verboseProcessing = feGetEnv("TR_VerboseLocalCSEAvailableSymRefs");
if (verboseProcessing)
{
traceMsg(comp(), " after n%dn [%p] seenAvailableLoadedSymbolReferences:", node->getGlobalIndex(), node);
seenAvailableLoadedSymbolReferences.print(comp());
traceMsg(comp(), "\n");
}
}
void OMR::LocalCSE::doCommoningAgainIfPreviouslyCommoned(TR::Node *node, TR::Node *parent, int32_t childNum)
{
for (int32_t i = 0; i < _nextReplacedNode;i++)
{
// If we have already seen this node before and commoned it up,
// then it will be present in the _replacedNodesAsArray data structure
// and we can common it up now again. When a parent node is commoned
// all its children get put into _replacedNodesAsArray (as they have
// common counterparts (children of node that the parent is commoned with)
//
if (_replacedNodesAsArray[i] == node &&
shouldCommonNode(parent, node) &&
performTransformation(comp(), "%s Local Common Subexpression Elimination commoning node : %p again\n", optDetailString(), node))
{
TR::Node *replacingNode = _replacedNodesByAsArray[i];
parent->setChild(childNum, replacingNode);
if (replacingNode->getReferenceCount() == 0)
recursivelyIncReferenceCount(replacingNode);
else
replacingNode->incReferenceCount();
if (node->getReferenceCount() <= 1)
optimizer()->prepareForNodeRemoval(node);
node->recursivelyDecReferenceCount();
if (parent->getOpCode().isResolveOrNullCheck() || ((parent->getOpCodeValue() == TR::compressedRefs) && (childNum == 0)))
{
TR::Node::recreate(parent, TR::treetop);
for (int32_t index =1;index < parent->getNumChildren(); index++)
parent->getChild(index)->recursivelyDecReferenceCount() ;
parent->setNumChildren(1);
}
break;
}
}
}
/**
* We can allow auto or parms which are not global during the volatile only phase
* as we do not expect those field to be changing. This enables up to common volatiles that are based on an
* indirection chain of such non volatile autos or parms that are not global by definition.
* Following query returns true if the node can be commoned in volatile only pass
*/
bool OMR::LocalCSE::canCommonNodeInVolatilePass(TR::Node *node)
{
return node->getOpCode().hasSymbolReference() && (node->getSymbol()->isVolatile() || node->getSymbol()->isAutoOrParm());
}
void OMR::LocalCSE::doCommoningIfAvailable(TR::Node *node, TR::Node *parent, int32_t childNum, bool &doneCommoning)
{
// If the expression can be available, search for it in the
// hash table and return the available expression; return NULL if
// no available expression was found to match this one.
//
TR::Node *availableExpression = getAvailableExpression(parent, node);
if (availableExpression && (availableExpression != node) &&
shouldCommonNode(parent, node) &&
performTransformation(comp(), "%s Local Common Subexpression Elimination commoning node : %p by available node : %p\n", optDetailString(), node, availableExpression))
{
if (!node->getOpCode().hasSymbolReference() ||
(_volatileState == VOLATILE_ONLY && canCommonNodeInVolatilePass(node)) ||
(_volatileState != VOLATILE_ONLY))
{
TR_ASSERT(_curBlock, "_curBlock should be non-null\n");
requestOpt(OMR::treeSimplification, true, _curBlock);
requestOpt(OMR::localReordering, true, _curBlock);
_mayHaveRemovedChecks = true;
if (parent != NULL)
{
// This node is not a treetop type node; so just make its
// (non NULL) parent point at the available child expression
//
doneCommoning = true;
manager()->setAlteredCode(true);
if (node->getLocalIndex() != REPLACE_MARKER)
collectAllReplacedNodes(node, availableExpression);
if ((!parent->getOpCode().isResolveOrNullCheck() &&
(parent->getOpCodeValue() != TR::DIVCHK)) &&
((parent->getOpCodeValue() != TR::compressedRefs) || (childNum != 0)))
commonNode(parent, childNum, node, availableExpression);
else
{
optimizer()->prepareForNodeRemoval(parent);
int32_t endIndex = _treeBeingExamined->getNode()->getNumChildren();
if (parent->getOpCodeValue() == TR::compressedRefs)
{
TR::Node::recreate(parent, TR::treetop);
for (int32_t index =1;index < parent->getNumChildren(); index++)
parent->getChild(index)->recursivelyDecReferenceCount() ;
parent->setNumChildren(1);
}
else
{
for (int32_t index =0;index < endIndex; index++)
_treeBeingExamined->getNode()->getChild(index)->recursivelyDecReferenceCount() ;
TR::TreeTop *prevTree = _treeBeingExamined->getPrevTreeTop();
TR::TreeTop *nextTree = _treeBeingExamined->getNextTreeTop();
prevTree->setNextTreeTop(nextTree);
nextTree->setPrevTreeTop(prevTree);
}
}
}
else
{
// This node is a treetop node; we might be able to remove the
// entire treetop if it is common (e.g. BNDCHK etc.)
//
TR::Node *node = _treeBeingExamined->getNode();
if (node->getOpCode().isResolveOrNullCheck())
{
TR_ASSERT(node->getNumChildren() == 1, "Local CSE, NULLCHK has more than one child");
// If the child of the nullchk is normally a treetop node, replace
// the nullchk with that node
//
if (node->getFirstChild()->getOpCode().isTreeTop())
{
if ((comp()->useAnchors() && node->getFirstChild()->getOpCode().isStoreIndirect()))
{
TR::Node::recreate(node, TR::treetop);
}
else
{
TR_ASSERT(node->getFirstChild()->getReferenceCount() == 1, "Local CSE, treetop child of NULLCHK has other uses");
// Make sure the child doesn't get removed too
//
node->getFirstChild()->incReferenceCount();
optimizer()->prepareForNodeRemoval(node);
node->getFirstChild()->setReferenceCount(0);
_treeBeingExamined->setNode(node->getFirstChild());
}
}
else
{
TR::Node::recreate(node, TR::treetop);
}
}
else
{
if (node->getLocalIndex() != REPLACE_MARKER)
collectAllReplacedNodes(node, availableExpression);
doneCommoning = true;
manager()->setAlteredCode(true);
optimizer()->prepareForNodeRemoval(node);
for (int32_t index =0;index < _treeBeingExamined->getNode()->getNumChildren(); index++)
_treeBeingExamined->getNode()->getChild(index)->recursivelyDecReferenceCount() ;
TR::TreeTop *prevTree = _treeBeingExamined->getPrevTreeTop();
TR::TreeTop *nextTree = _treeBeingExamined->getNextTreeTop();
prevTree->setNextTreeTop(nextTree);
nextTree->setPrevTreeTop(prevTree);
}
}
}
else
{
if (trace())
traceMsg(comp(), "Simulating commoning of node n%dn with n%dn - current mode %n\n", node->getGlobalIndex(), availableExpression->getGlobalIndex(), _volatileState);
_simulatedNodesAsArray[node->getGlobalIndex()] = availableExpression;
}
}
}
bool OMR::LocalCSE::doCopyPropagationIfPossible(TR::Node *node, TR::Node *parent, int32_t childNum, TR::Node *storeNode, TR::SymbolReference *symRef, vcount_t visitCount, bool &doneCopyPropagation)
{
if (!shouldCopyPropagateNode(parent, node, childNum, storeNode))
return false;
int32_t childAdjust = storeNode->getOpCode().isWrtBar() ? 2 : 1;
int32_t maxChild = storeNode->getNumChildren() - childAdjust;
TR::Node *rhsOfStoreDefNode = storeNode->getChild(maxChild);
bool isSafeToCommon = true;
if (!shouldCommonNode(node, rhsOfStoreDefNode))
isSafeToCommon = false;
if ((!comp()->getOption(TR_MimicInterpreterFrameShape) ||
!comp()->areSlotsSharedByRefAndNonRef() ||
!symRef->getSymbol()->isAuto() ||
!symRef->getSymbol()->castToAutoSymbol()->isSlotSharedByRefAndNonRef()) &&
shouldCommonNode(parent, node) &&
isSafeToCommon &&
canAffordToIncreaseRegisterPressure() &&
(!node->getOpCode().hasSymbolReference() ||
node->getSymbolReference() != comp()->getSymRefTab()->findVftSymbolRef()) &&
(symRef->storeCanBeRemoved() ||
(!symRef->getSymbol()->isVolatile() &&
rhsOfStoreDefNode->getDataType() == TR::Float &&
(rhsOfStoreDefNode->getOpCode().isCall() ||
(rhsOfStoreDefNode->getOpCode().isLoadConst()) ||
rhsOfStoreDefNode->getOpCode().isLoadVar()))) &&
(!parent->getOpCode().isSpineCheck() || childNum != 0) &&
performTransformation(comp(), "%s Local Common Subexpression Elimination propagating local #%d in node : %p PARENT : %p from node %p\n", optDetailString(), symRef->getReferenceNumber(), node, parent, storeNode))
{
//TR::SymbolReference *originalSymbolReference = rhsOfStoreDefNode->getSymbolReference();
dumpOptDetails(comp(), "%s Rhs of store def node : %p\n", optDetailString(), rhsOfStoreDefNode);
TR_ASSERT(_curBlock, "_curBlock should be non-null\n");
requestOpt(OMR::treeSimplification, true, _curBlock);
requestOpt(OMR::localReordering, true, _curBlock);
#ifdef J9_PROJECT_SPECIFIC
// Set InMemoryCopyProp flag to help codegen evaluators distinguish between potential memory overlap
// created by the optimizer (vs present from the start) for in memory types (i.e. BCD and Aggregate)
setIsInMemoryCopyPropFlag(rhsOfStoreDefNode);
#endif
prepareToCopyPropagate(node, rhsOfStoreDefNode);
TR_ASSERT(parent, "No parent for eliminated expression");
manager()->setAlteredCode(true);
rhsOfStoreDefNode = replaceCopySymbolReferenceByOriginalIn(symRef/*, originalSymbolReference*/, storeNode, rhsOfStoreDefNode, node, parent, childNum);
node->setVisitCount(visitCount);
_replacedNodesAsArray[_nextReplacedNode] = node;
_replacedNodesByAsArray[_nextReplacedNode++] = rhsOfStoreDefNode;
if (parent->getOpCode().isResolveOrNullCheck() || ((parent->getOpCodeValue() == TR::compressedRefs) && (childNum == 0)))
{
TR::Node::recreate(parent, TR::treetop);
for (int32_t index =1;index < parent->getNumChildren(); index++)
parent->getChild(index)->recursivelyDecReferenceCount() ;
parent->setNumChildren(1);
}
doneCopyPropagation = true;
_numCopyPropagations++;
return true;
}
return false;
}
// Adjusts the availability information for the given node; called when
// the node is being examined by commoning
//
void OMR::LocalCSE::makeNodeAvailableForCommoning(TR::Node *parent, TR::Node *node, TR_BitVector &seenAvailableLoadedSymbolReferences, bool *canBeAvailable)
{
if (parent &&
(parent->getOpCodeValue() == TR::Prefetch) &&
(parent->getFirstChild() == node))
return;
if (comp()->cg()->supportsLengthMinusOneForMemoryOpts() && parent && parent->getOpCode().isMemToMemOp())
{
if (parent->getLastChild() == node)
return;
}
if (node->getOpCode().hasSymbolReference())
{
if (!seenAvailableLoadedSymbolReferences.get(node->getSymbolReference()->getReferenceNumber()))
{
*canBeAvailable = false;
if (_inSubTreeOfNullCheckReference)
_isAvailableNullCheck = false;
if (node->getOpCode().isLoadVar() ||
node->getOpCode().isCheck() ||
node->getOpCode().isCall() ||
node->getOpCodeValue() == TR::instanceof ||
((node->getOpCodeValue() == TR::loadaddr) &&
(node->getSymbol()->isNotCollected() ||
node->getSymbol()->isAutoOrParm())))
{
bool isCallDirect = false;