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FieldPrivatizer.cpp
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FieldPrivatizer.cpp
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/*******************************************************************************
* Copyright (c) 2000, 2019 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/FieldPrivatizer.hpp"
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include "codegen/CodeGenerator.hpp"
#include "env/FrontEnd.hpp"
#include "compile/Compilation.hpp"
#include "compile/ResolvedMethod.hpp"
#include "compile/SymbolReferenceTable.hpp"
#include "control/Options.hpp"
#include "control/Options_inlines.hpp"
#include "env/StackMemoryRegion.hpp"
#include "env/TRMemory.hpp"
#include "il/AliasSetInterface.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/Cfg.hpp"
#include "infra/HashTab.hpp"
#include "infra/List.hpp"
#include "infra/CfgEdge.hpp"
#include "infra/CfgNode.hpp"
#include "optimizer/Inliner.hpp"
#include "optimizer/Optimization_inlines.hpp"
#include "optimizer/OptimizationManager.hpp"
#include "optimizer/Optimizations.hpp"
#include "optimizer/Optimizer.hpp"
#include "optimizer/RegisterCandidate.hpp"
#include "optimizer/Structure.hpp"
#include "optimizer/Dominators.hpp"
#include "optimizer/LocalAnalysis.hpp"
#include "optimizer/ValueNumberInfo.hpp"
#include "optimizer/IsolatedStoreElimination.hpp"
#include "optimizer/LoopCanonicalizer.hpp"
TR_FieldPrivatizer::TR_FieldPrivatizer(TR::OptimizationManager *manager)
: TR_LoopTransformer(manager),
_privatizedFieldSymRefs(manager->trMemory(), stackAlloc),
_privatizedRegCandidates(manager->trMemory()),
_appendCalls(manager->trMemory()),
_privatizedFieldNodes(manager->trMemory()),
_subtreeCheckedForSpecialConditions(manager->comp()),
_subtreeHasSpecialCondition(manager->comp())
{
}
int32_t TR_FieldPrivatizer::perform()
{
// Need to confirm places calling opCodeFor* APIs are doing the right
// thing for readbar and wrtbar. All the transformations applied to normal
// load/store s should be applied to rd/wrtbar s. However, we need to be
// careful about the difference in the shape of the trees and the
// mapping relationship between different loads and stores
if (comp()->incompleteOptimizerSupportForReadWriteBarriers())
return 0;
TR::StackMemoryRegion stackMemoryRegion(*trMemory());
_postDominators = NULL;
detectCanonicalizedPredictableLoops(comp()->getFlowGraph()->getStructure(), 0, -1);
TR::TreeTop *node;
ListIterator<TR::TreeTop> si(&_appendCalls);
for (node = si.getCurrent(); node != 0; node = si.getNext())
{
#ifdef J9_PROJECT_SPECIFIC
TR_InlineCall newInlineCall(optimizer(), this);
newInlineCall.inlineCall(node);
requestOpt(OMR::expensiveObjectAllocationGroup);
#endif
}
return 1;
}
bool TR_FieldPrivatizer::isFieldAliasAccessed(TR::SymbolReference * symRef)
{
bool aliasAccessed = false;
if (symRef->getUseDefAliases().hasAliases())
{
TR_ASSERT(_allSymRefs[symRef->getReferenceNumber()] == true, "symRef should have been seen in the loop");
_allSymRefs[symRef->getReferenceNumber()] = false;
if (symRef->getUseDefAliases().containsAny(_allSymRefs, comp()))
{
aliasAccessed = true;
}
_allSymRefs[symRef->getReferenceNumber()] = true;
}
return aliasAccessed;
}
int32_t TR_FieldPrivatizer::detectCanonicalizedPredictableLoops(TR_Structure *loopStructure, TR_BitVector **optSetInfo, int32_t bitVectorSize)
{
TR_RegionStructure *regionStructure = loopStructure->asRegion();
if (regionStructure)
{
TR_StructureSubGraphNode *node;
TR_RegionStructure::Cursor si(*regionStructure);
for (node = si.getCurrent(); node != 0; node = si.getNext())
detectCanonicalizedPredictableLoops(node->getStructure(), optSetInfo, bitVectorSize);
}
TR_BlockStructure *loopInvariantBlock = 0;
if (!regionStructure ||
!regionStructure->getParent() ||
!regionStructure->isNaturalLoop())
return 0;
// traceMsg(comp(), "Considering Loop %d\n", regionStructure->getNumber());
TR_ScratchList<TR::Block> blocksInRegion(trMemory());
regionStructure->getBlocks(&blocksInRegion);
ListIterator<TR::Block> blocksIt(&blocksInRegion);
TR::Block *nextBlock;
for (nextBlock = blocksIt.getCurrent(); nextBlock; nextBlock=blocksIt.getNext())
if (nextBlock->hasExceptionPredecessors())
return 0;
TR::Block * loopEntryBlock = regionStructure->getEntryBlock();
for(auto predecessor = loopEntryBlock->getPredecessors().begin(); predecessor != loopEntryBlock->getPredecessors().end(); ++predecessor)
{
TR::Block * predBlock = toBlock((*predecessor)->getFrom());
if(predBlock == comp()->getFlowGraph()->getStart()->asBlock())
return 0;
}
TR_RegionStructure *parentStructure = regionStructure->getParent()->asRegion();
TR_StructureSubGraphNode *subNode = 0;
TR_RegionStructure::Cursor si(*parentStructure);
for (subNode = si.getCurrent(); subNode != 0; subNode = si.getNext())
{
if (subNode->getNumber() == loopStructure->getNumber())
break;
}
if ((subNode->getPredecessors().size() == 1))
{
TR_StructureSubGraphNode *loopInvariantNode = toStructureSubGraphNode(subNode->getPredecessors().front()->getFrom());
if (loopInvariantNode->getStructure()->asBlock() &&
loopInvariantNode->getStructure()->asBlock()->isLoopInvariantBlock())
loopInvariantBlock = loopInvariantNode->getStructure()->asBlock();
}
_currLoopStructure = loopStructure;
bool canTransform = true;
if (!loopInvariantBlock &&
(regionStructure->getEntryBlock() != comp()->getStartBlock()))
{
TR::Block *entryBlock = regionStructure->getEntryBlock();
for (auto pred = entryBlock->getPredecessors().begin(); pred != entryBlock->getPredecessors().end(); ++pred)
{
TR::Block *predBlock = toBlock((*pred)->getFrom());
if (blocksInRegion.find(predBlock))
continue;
TR::Node *node = predBlock->getLastRealTreeTop()->getNode();
if(node->getOpCodeValue() == TR::treetop)
node = node->getFirstChild();
if (node->getOpCode().isJumpWithMultipleTargets() && !node->getOpCode().hasBranchChildren())
{
canTransform = false;
break;
}
}
}
if (canTransform &&
!loopInvariantBlock &&
(regionStructure->getEntryBlock() != comp()->getStartBlock()))
{
TR::Block *entryBlock = regionStructure->getEntryBlock();
int32_t sumPredFreq = 0;
for (auto pred = entryBlock->getPredecessors().begin(); pred != entryBlock->getPredecessors().end(); ++pred)
{
TR::Block *predBlock = toBlock((*pred)->getFrom());
if (!blocksInRegion.find(predBlock))
sumPredFreq = sumPredFreq + (*pred)->getFrequency();
}
TR::Block *newBlock = TR::Block::createEmptyBlock(entryBlock->getEntry()->getNode(), comp(), sumPredFreq < 0 ? 0 : sumPredFreq, entryBlock);
bool insertAsFallThrough = false;
TR::CFG * cfg = comp()->getFlowGraph();
cfg->addNode(newBlock, parentStructure);
TR::CFGEdge *entryEdge = cfg->addEdge(newBlock, entryBlock);
entryEdge->setFrequency(sumPredFreq);
TR::TreeTop *lastTreeTop = comp()->getMethodSymbol()->getLastTreeTop();
for (auto pred = entryBlock->getPredecessors().begin(); pred != entryBlock->getPredecessors().end();)
{
TR::Block *predBlock = toBlock((*pred)->getFrom());
if ((predBlock != newBlock) &&
!blocksInRegion.find(predBlock))
{
predBlock->getLastRealTreeTop()->adjustBranchOrSwitchTreeTop(comp(), entryBlock->getEntry(), newBlock->getEntry());
if (predBlock->getNextBlock() == entryBlock)
{
insertAsFallThrough = true;
}
TR::CFGEdge *newEdge = cfg->addEdge(predBlock, newBlock);
newEdge->setFrequency((*(pred++))->getFrequency());
cfg->removeEdge(predBlock, entryBlock);
}
else
++pred;
}
TR::TreeTop *gotoTreeTop = TR::TreeTop::create(comp(), TR::Node::create(entryBlock->getEntry()->getNode(), TR::Goto, 0, entryBlock->getEntry()));
newBlock->append(gotoTreeTop);
TR::TreeTop *entryTree = entryBlock->getEntry();
if (insertAsFallThrough)
{
TR::TreeTop *prevTree = entryTree->getPrevTreeTop();
prevTree->join(newBlock->getEntry());
newBlock->getExit()->join(entryTree);
}
else
{
lastTreeTop->join(newBlock->getEntry());
lastTreeTop = newBlock->getExit();
}
loopInvariantBlock = newBlock->getStructureOf();
}
if (loopInvariantBlock &&
((loopInvariantBlock->getBlock()->getPredecessors().size() == 1) ||
loopInvariantBlock->getBlock()->getFirstRealTreeTop() == loopInvariantBlock->getBlock()->getLastRealTreeTop()))
{
int32_t symRefCount = comp()->getSymRefCount();
initializeSymbolsWrittenAndReadExactlyOnce(symRefCount, notGrowable);
_privatizedFields = new (trStackMemory()) TR_BitVector(symRefCount, trMemory(), stackAlloc);
_fieldsThatCannotBePrivatized = new (trStackMemory()) TR_BitVector(symRefCount, trMemory(), stackAlloc);
_needToStoreBack = new (trStackMemory()) TR_BitVector(symRefCount, trMemory(), stackAlloc, growable);
_criticalEdgeBlock = 0;
if (trace())
traceMsg(comp(), "\nChecking loop %d for predictability\n", loopStructure->getNumber());
_isAddition = false;
int32_t isPredictableLoop = checkLoopForPredictability(loopStructure, loopInvariantBlock->getBlock(), 0);
if (isPredictableLoop <= 0)
{
vcount_t visitCount = comp()->incVisitCount();
initializeSymbolsWrittenAndReadExactlyOnce(symRefCount, notGrowable);
collectSymbolsWrittenAndReadExactlyOnce(loopStructure, visitCount);
}
bool loopContainsStringPeephole = false;
_stringPeepholeTree = 0;
_tempStringSymRef = 0;
_stringSymRef = 0;
_valueOfSymRef = 0;
bool loopContainsEscapePoints = containsEscapePoints(loopStructure, loopContainsStringPeephole);
if (_stringPeepholeTree &&
!_stringSymRef->getUseonlyAliases().hasAliases() &&
!_valueOfSymRef->getUseonlyAliases().hasAliases())
{
_toStringSymRef = 0;
_initSymRef = 0;
_appendSymRef = 0;
_stringBufferClass = fe()->getClassFromSignature("java/lang/StringBuffer", 22, comp()->getCurrentMethod());
if (_stringBufferClass)
{
TR::Block *invariantBlock = loopInvariantBlock->getBlock();
addStringInitialization(invariantBlock);
TR_ScratchList<TR::Block> exitBlocks(trMemory());
loopStructure->collectExitBlocks(&exitBlocks);
placeStringEpilogueInExits(&exitBlocks, &blocksInRegion);
cleanupStringPeephole();
}
}
if (isPredictableLoop > 0)
{
if (!loopContainsEscapePoints)
{
_privatizedFieldNodes.deleteAll();
_privatizedFields->empty();
_fieldsThatCannotBePrivatized->empty();
vcount_t visitCount = comp()->incVisitCount();
detectFieldsThatCannotBePrivatized(loopStructure, visitCount);
_privatizedFields->empty();
_privatizedFieldNodes.deleteAll();
if (trace())
{
traceMsg(comp(), "\nDetected a predictable loop %d\n", loopStructure->getNumber());
traceMsg(comp(), "Fields that cannot be privatized:\n");
_fieldsThatCannotBePrivatized->print(comp());
traceMsg(comp(), "\n");
traceMsg(comp(), "\nPossible new induction variable candidates :\n");
}
visitCount = comp()->incVisitCount();
privatizeNonEscapingLoop(loopStructure, regionStructure->getEntryBlock(), visitCount);
TR_ScratchList<TR::Block> exitBlocks(trMemory());
if (!_privatizedFieldNodes.isEmpty())
{
loopStructure->collectExitBlocks(&exitBlocks);
TR::Block *invariantBlock = loopInvariantBlock->getBlock();
//placeInitializersInLoopInvariantBlock(invariantBlock);
TR::Block *pred = toBlock(invariantBlock->getPredecessors().front()->getFrom());
TR::Block *next;
for (auto edge = pred->getSuccessors().begin(); edge != pred->getSuccessors().end(); ++edge)
{
next = toBlock((*edge)->getTo());
if (next != invariantBlock)
{
bool joinHasPredInLoop = false;
if (next->getSuccessors().size() == 1)
{
TR::Block *join = next->getSuccessors().front()->getTo()->asBlock();
for (auto predEdge = join->getPredecessors().begin(); predEdge != join->getPredecessors().end(); ++predEdge)
{
if (blocksInRegion.find((*predEdge)->getFrom()->asBlock()))
{
joinHasPredInLoop = true;
break;
}
}
}
// The assumption is that _criticalEdge block should be
// a block inserted by loop canonicalizer to account for the
// control flow path where the test done outside the loop fails
// and the canonicalized loop is never entered. If it is not,
// then we don't have the loop in the exact form we would like
// and so we will insert store backs inside the loop (because
// _criticalEdgeBlock will be 0 as the 'if' below will not be
// entered)
//
if (joinHasPredInLoop)
{
_criticalEdgeBlock = next;
placeInitializersInLoopInvariantBlock(next);
}
}
else
placeInitializersInLoopInvariantBlock(next);
}
addPrivatizedRegisterCandidates(loopStructure);
placeStoresBackInExits(&exitBlocks, &blocksInRegion);
}
}
}
}
return 0;
}
bool TR_FieldPrivatizer::subtreeHasSpecialCondition(TR::Node *node)
{
bool hasSpecialCondition = false;
if (_subtreeCheckedForSpecialConditions.contains(node))
{
hasSpecialCondition = _subtreeHasSpecialCondition.contains(node);
}
else
{
TR::ILOpCodes opCode = node->getOpCodeValue();
if (opCode == TR::instanceof)
{
hasSpecialCondition = true;
}
else if (opCode == TR::acmpeq || opCode == TR::acmpne || opCode == TR::ifacmpeq || opCode == TR::ifacmpne)
{
TR::Node *leftChild = node->getFirstChild();
TR::Node *rightChild = node->getSecondChild();
if ((leftChild->getOpCodeValue() == TR::aconst && leftChild->getAddress() == 0)
|| (rightChild->getOpCodeValue() == TR::aconst && rightChild->getAddress() == 0))
{
hasSpecialCondition = true;
}
}
else
{
for (int i = 0; i < node->getNumChildren(); i++)
{
if (subtreeHasSpecialCondition(node->getChild(i)))
{
hasSpecialCondition = true;
}
}
}
_subtreeCheckedForSpecialConditions.add(node);
if (hasSpecialCondition)
{
_subtreeHasSpecialCondition.add(node);
}
}
return hasSpecialCondition;
}
bool TR_FieldPrivatizer::containsEscapePoints(TR_Structure *structure, bool &containsStringPeephole)
{
bool result = false;
if (structure->asBlock() != 0)
{
TR_BlockStructure *blockStructure = structure->asBlock();
TR::Block *block = blockStructure->getBlock();
TR::TreeTop *exitTree = block->getExit();
TR::TreeTop *currentTree = block->getEntry();
while (currentTree != exitTree)
{
TR::Node *currentNode = currentTree->getNode();
// Check for situations that can be a problem for privatization:
//
// (1) Exceptions that might be thrown
// (2) Certain conditions that are being checked, as they might be
// used to guard access of a field that might not be valid in any
// particular execution of the loop. The only conditions checked
// for currently are inlined method guards, instanceof tests and
// comparisons to null.
//
// N.B., checking for inline guards, instanceof and null comparisons
// helps to avoid some potential errors in privatization temporarily,
// but a more general, correct, solution needs to replace this -
// one that proves the type of the object whose fields might be
// privatized must be of the expected type in the loop, and that
// ensures any conditional access in the original loop is handled
// correctly. This follow on work will be performed under OMR issue
// <https://github.com/eclipse/omr/issues/6199>
//
if (currentNode->exceptionsRaised()
|| currentNode->isTheVirtualGuardForAGuardedInlinedCall()
|| subtreeHasSpecialCondition(currentNode))
{
result = true;
}
// DISABLED for now, although an excellent general purpose opt,
// this causes a regression, because the loop runs <= 1 times
// Enable this only when it is known (via profiling that the loop goes > 1
// times)
//
// if (isStringPeephole(currentNode, currentTree))
// containsStringPeephole = true;
currentTree = currentTree->getNextTreeTop();
}
}
else
{
TR_RegionStructure *regionStructure = structure->asRegion();
TR_StructureSubGraphNode *node;
TR_RegionStructure::Cursor si(*regionStructure);
for (node = si.getCurrent(); node != 0; node = si.getNext())
{
if (containsEscapePoints(node->getStructure(), containsStringPeephole))
result = true;
}
}
return result;
}
bool TR_FieldPrivatizer::isStringPeephole(TR::Node *currentNode, TR::TreeTop *currentTree)
{
bool foundStringPeephole = false;
if (currentNode->getOpCode().isTreeTop() &&
(currentNode->getNumChildren() > 0))
{
currentNode = currentNode->getFirstChild();
if (currentNode->getOpCodeValue() == TR::call &&
!currentNode->getSymbolReference()->isUnresolved())
{
TR_ResolvedMethod *method = currentNode->getSymbolReference()->getSymbol()->castToResolvedMethodSymbol()->getResolvedMethod();
if (method->isConstructor())
{
char *sig = method->signatureChars();
if (!strncmp(sig, "(Ljava/lang/String;C)", 21))
{
TR::Node *valueOfString = currentNode->getSecondChild();
if (valueOfString->getOpCode().hasSymbolReference() &&
currentNode->getFirstChild()->getOpCodeValue() == TR::New)
{
TR::TreeTop *prevTree = currentTree->getPrevTreeTop();
TR::Node *prevNode = prevTree->getNode();
if (prevNode->getOpCode().isStore())
{
_stringSymRef = prevNode->getSymbolReference();
_valueOfSymRef = valueOfString->getSymbolReference();
prevTree = prevTree->getPrevTreeTop();
while (prevTree->getNode()->getOpCodeValue() != TR::BBStart)
{
prevNode = prevTree->getNode();
if (prevNode->getOpCode().isStore() &&
prevNode->getSymbolReference() == _valueOfSymRef &&
prevNode->getFirstChild()->getOpCode().isLoadVarDirect() &&
prevNode->getFirstChild()->getSymbolReference() == _stringSymRef)
{
foundStringPeephole = true;
break;
}
prevTree = prevTree->getPrevTreeTop();
}
if (foundStringPeephole)
{
if (!_writtenExactlyOnce.ValueAt(_stringSymRef->getReferenceNumber()) ||
!_readExactlyOnce.ValueAt(_stringSymRef->getReferenceNumber()) ||
!_writtenExactlyOnce.ValueAt(_valueOfSymRef->getReferenceNumber()) ||
!_readExactlyOnce.ValueAt(_valueOfSymRef->getReferenceNumber()))
foundStringPeephole = false;
}
if (foundStringPeephole)
{
_stringPeepholeTree = currentTree;
}
}
}
}
}
}
}
return foundStringPeephole;
}
void TR_FieldPrivatizer::detectFieldsThatCannotBePrivatized(TR_Structure *structure, vcount_t visitCount)
{
if (structure->asBlock() != 0)
{
TR_BlockStructure *blockStructure = structure->asBlock();
TR::Block *block = blockStructure->getBlock();
TR::TreeTop *exitTree = block->getExit();
TR::TreeTop *currentTree = block->getEntry();
while (currentTree != exitTree)
{
TR::Node *currentNode = currentTree->getNode();
detectFieldsThatCannotBePrivatized(currentNode, visitCount);
currentTree = currentTree->getNextTreeTop();
}
}
else
{
TR_RegionStructure *regionStructure = structure->asRegion();
TR_StructureSubGraphNode *node;
TR_RegionStructure::Cursor si(*regionStructure);
for (node = si.getCurrent(); node != 0; node = si.getNext())
detectFieldsThatCannotBePrivatized(node->getStructure(), visitCount);
}
}
void TR_FieldPrivatizer::detectFieldsThatCannotBePrivatized(TR::Node *node, vcount_t visitCount)
{
if (node->getVisitCount() == visitCount)
return;
node->setVisitCount(visitCount);
TR::ILOpCode &opCode = node->getOpCode();
// Check if field cannot be privatized
if (opCode.isStore() || opCode.isLoadVar())
{
TR::SymbolReference *symRef = node->getSymbolReference();
TR::Symbol *sym = symRef->getSymbol();
bool staticSym = sym->isStatic();
size_t symSize = sym->getSize();
if ((opCode.isIndirect() || staticSym))
{
bool canPrivatize = true;
if (!TR_LocalAnalysis::isSupportedNodeForFieldPrivatization(node, comp(), NULL))
canPrivatize = false;
if (canPrivatize &&
!sym->isArrayShadowSymbol() &&
!sym->isVolatile() &&
comp()->cg()->considerTypeForGRA(symRef) &&
!_neverWritten->get(symRef->getReferenceNumber()) &&
(opCode.isIndirect() ? subtreeIsInvariantInLoop(node->getFirstChild()) : true) &&
!isFieldAliasAccessed(symRef) &&
(symSize <= 8 || sym->getType().isVector()))
{
bool canPrivatizeBasedOnThisNode = canPrivatizeFieldSymRef(node);
if (!canPrivatizeBasedOnThisNode)
{
if (!_privatizedFields->get(symRef->getReferenceNumber()))
{
_privatizedFields->set(symRef->getReferenceNumber());
_privatizedFieldNodes.add(node->duplicateTree());
}
else
{
_fieldsThatCannotBePrivatized->set(symRef->getReferenceNumber());
}
}
}
else
{
_fieldsThatCannotBePrivatized->set(symRef->getReferenceNumber());
}
}
else
{
_fieldsThatCannotBePrivatized->set(symRef->getReferenceNumber());
}
}
int32_t i;
for (i=0;i<node->getNumChildren();i++)
detectFieldsThatCannotBePrivatized(node->getChild(i), visitCount);
}
void TR_FieldPrivatizer::privatizeNonEscapingLoop(TR_Structure *structure, TR::Block *entryBlock, vcount_t visitCount)
{
if (structure->asBlock() != 0)
{
TR_BlockStructure *blockStructure = structure->asBlock();
TR::Block *block = blockStructure->getBlock();
TR::TreeTop *exitTree = block->getExit();
TR::TreeTop *currentTree = block->getEntry();
bool postDominatesEntry = _postDominators && _postDominators->dominates(block, entryBlock);
while (currentTree != exitTree)
{
TR::Node *currentNode = currentTree->getNode();
privatizeFields(currentNode, postDominatesEntry, visitCount);
currentTree = currentTree->getNextTreeTop();
}
}
else
{
TR_RegionStructure *regionStructure = structure->asRegion();
TR_StructureSubGraphNode *node;
TR_RegionStructure::Cursor si(*regionStructure);
for (node = si.getCurrent(); node != 0; node = si.getNext())
privatizeNonEscapingLoop(node->getStructure(), entryBlock, visitCount);
}
}
void TR_FieldPrivatizer::privatizeFields(TR::Node *node, bool postDominatesEntry, vcount_t visitCount)
{
if (node->getVisitCount() == visitCount)
return;
node->setVisitCount(visitCount);
TR::ILOpCode &opCode = node->getOpCode();
TR::DataType nodeType = node->getType();
TR::DataType nodeDataType = node->getDataType();
// privatize
if (opCode.isStore() || opCode.isLoadVar())
{
TR::SymbolReference *symRef = node->getSymbolReference();
TR::Symbol *sym = symRef->getSymbol();
size_t symSize = sym->getSize();
// Don't add legal here, add it to detectFieldsThatCannotBePrivatized
if (!_fieldsThatCannotBePrivatized->get(symRef->getReferenceNumber()))
{
TR::SymbolReference *autoForField = 0;
//
// See if it can be privatized
//
//if (_privatizedFields->get(symRef->getReferenceNumber()))
autoForField = getPrivatizedFieldAutoSymRef(node);
bool canPrivatizeBasedOnThisNode = performTransformation(comp(), "%s Field access %p using sym ref %d privatized ", optDetailString(), node, symRef->getReferenceNumber());
if (canPrivatizeBasedOnThisNode)
{
if (!autoForField)
{
// Create a new auto for this field
//
TR_HashId index = 0;
_privatizedFields->set(symRef->getReferenceNumber());
autoForField = comp()->getSymRefTab()->createTemporary(comp()->getMethodSymbol(), nodeDataType,false,symSize);
_privatizedFieldSymRefs.add(symRef->getReferenceNumber(),index,autoForField);
_privatizedRegCandidates.add(comp()->getGlobalRegisterCandidates()->findOrCreate(autoForField));
_privatizedFieldNodes.add(node->duplicateTree());
}
else if (!_privatizedFields->get(symRef->getReferenceNumber()))
{
_privatizedFields->set(symRef->getReferenceNumber());
//Even we are reusing temp, need to save this for initialization and store back
_privatizedFieldNodes.add(node->duplicateTree());
}
dumpOptDetails(comp(), "using auto %d\n", autoForField->getReferenceNumber());
node->setSymbolReference(autoForField);
TR::Node *newFirstChild = 0;
int32_t newFirstChildNum = -1;
if (opCode.isIndirect())
{
if (opCode.isStore())
{
_needToStoreBack->set(autoForField->getReferenceNumber());
TR::Node::recreate(node, comp()->il.opCodeForDirectStore(nodeDataType));
newFirstChild = node->getSecondChild();
newFirstChildNum = 1;
}
else
{
TR::Node::recreate(node, comp()->il.opCodeForDirectLoad(nodeDataType));
}
for (int32_t i = 0; i < node->getNumChildren(); i++)
{
if (i != newFirstChildNum)
{
node->getChild(i)->recursivelyDecReferenceCount();
}
}
if (newFirstChild)
{
node->setChild(0, newFirstChild);
node->setNumChildren(1);
}
else
{
node->setNumChildren(0);
}
}
else
{
if (opCode.isStore())
{
_needToStoreBack->set(autoForField->getReferenceNumber());
if (node->getOpCodeValue() == TR::awrtbar)
{
node->getChild(1)->recursivelyDecReferenceCount();
node->setNumChildren(1);
TR::Node::recreate(node, comp()->il.opCodeForDirectStore(nodeDataType));
}
}
}
}
}
}
for (int32_t i = 0; i < node->getNumChildren(); i++)
{
privatizeFields(node->getChild(i), postDominatesEntry, visitCount);
}
}
bool TR_FieldPrivatizer::canPrivatizeFieldSymRef(TR::Node *node)
{
ListElement<TR::Node> *currentNodeElem = _privatizedFieldNodes.getListHead();
while (currentNodeElem)
{
TR::Node *currentNode = currentNodeElem->getData();
TR::SymbolReference *symRefInCurrentNode = currentNode->getSymbolReference();
TR::SymbolReference *symRef = node->getSymbolReference();
if (symRefInCurrentNode->getReferenceNumber() == symRef->getReferenceNumber())
{
// Found a node that looks likely to have been privatized
//
if (!node->getOpCode().isIndirect())
return true;
if (bothSubtreesMatch(currentNode->getFirstChild(), node->getFirstChild()))
return true;
else
return false;
}
currentNodeElem = currentNodeElem->getNextElement();
}
// This return false here has 2 meanings:
// 1. If the symref is in _privatizedFields then we add this node to the list of those that can't be privatized.
// 2. If the symref is NOT in _privatizedFields we add it to privatized fields, so essentially it's a true.
return false;
}
TR::SymbolReference *TR_FieldPrivatizer::getPrivatizedFieldAutoSymRef(TR::Node *node)
{
TR::SymbolReference *symRef = node->getSymbolReference();
TR_HashId index = 0;
if (_privatizedFieldSymRefs.locate(symRef->getReferenceNumber(),index))
{
return ((TR::SymbolReference *)_privatizedFieldSymRefs.getData(index));
}
return 0;
}
bool TR_FieldPrivatizer::bothSubtreesMatch(TR::Node *node1, TR::Node *node2)
{
if (node1 == node2)
return true;
if (node1->getOpCodeValue() == node2->getOpCodeValue())
{
if (node1->getOpCode().isLoadVar() ||
(node1->getOpCodeValue() == TR::loadaddr && node1->getSymbolReference()->getSymbol()->isNotCollected()))
{
if (node1->getSymbolReference()->getReferenceNumber() == node2->getSymbolReference()->getReferenceNumber())
{
if (node1->getNumChildren() > 0)
{
if (bothSubtreesMatch(node1->getFirstChild(), node2->getFirstChild()))
return true;
}
else
{
return true;
}
}
}
}
return false;
}
bool TR_FieldPrivatizer::subtreeIsInvariantInLoop(TR::Node *node)
{
if (node->getOpCodeValue() == TR::loadaddr && node->getSymbolReference()->getSymbol()->isNotCollected())
{
return true;
}
if ((node->getNumChildren() > 1) ||
!node->getOpCode().isLoadVar() ||
!_neverWritten->get(node->getSymbolReference()->getReferenceNumber()) ||
((node->getNumChildren() > 0) &&
!subtreeIsInvariantInLoop(node->getFirstChild())))
return false;
return true;
}
void TR_FieldPrivatizer::placeInitializersInLoopInvariantBlock(TR::Block *block)
{
ListElement<TR::Node> *currentNodeElem = _privatizedFieldNodes.getListHead();
TR::SymbolReference *currentSymRef = NULL;
//TR::TreeTop *insertionPoint = block->getEntry();
TR::TreeTop *placeHolderTree = block->getLastRealTreeTop();
TR::Node *placeHolderNode = placeHolderTree->getNode();
if(placeHolderNode->getOpCodeValue() == TR::treetop)
placeHolderNode = placeHolderNode->getFirstChild();
TR::ILOpCode &placeHolderOpCode = placeHolderNode->getOpCode();
if (placeHolderOpCode.isBranch() ||
placeHolderOpCode.isJumpWithMultipleTargets() ||
placeHolderOpCode.isReturn() ||
placeHolderOpCode.getOpCodeValue() == TR::athrow)
{
}
else
placeHolderTree = block->getExit();
TR::TreeTop *treeBeforePlaceHolderTree = placeHolderTree->getPrevTreeTop();
TR_HashId index = 0;
while (currentNodeElem)
{
TR::Node *currentNode = currentNodeElem->getData();
TR::Node *duplicateNode = currentNode->duplicateTree();
if (duplicateNode->getOpCode().isStore())
{
if (duplicateNode->getOpCode().isIndirect())
{
TR::Node::recreate(duplicateNode, comp()->il.opCodeForCorrespondingIndirectStore(duplicateNode->getOpCodeValue()));
duplicateNode->setNumChildren(1);
}
else
{
TR::Node::recreate(duplicateNode, comp()->il.opCodeForDirectLoad(duplicateNode->getDataType()));
duplicateNode->setNumChildren(0);
}
}
TR::SymbolReference *symRef = duplicateNode->getSymbolReference();
if (_privatizedFieldSymRefs.locate(symRef->getReferenceNumber(),index))
{
currentSymRef = ((TR::SymbolReference *)_privatizedFieldSymRefs.getData(index));
}
else
TR_ASSERT(false, "\n field #%d should have been privatized but didn't find corresponding new auto in _privatizedFieldSymRefs", symRef->getReferenceNumber());
dumpOptDetails(comp(), "%s Privatizing field #%d with temp #%d\n", optDetailString(), duplicateNode->getSymbolReference()->getReferenceNumber(), currentSymRef->getReferenceNumber());
//if (performTransformation(comp(), "%s Privatizing field #%d with temp #%d\n", optDetailString(), duplicateNode->getSymbolReference()->getReferenceNumber(), currentSymRefElem->getData()->getReferenceNumber()))