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LoopVersioner.cpp
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LoopVersioner.cpp
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/*******************************************************************************
* 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 "optimizer/LoopVersioner.hpp"
#include <algorithm>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "codegen/CodeGenerator.hpp"
#include "env/FrontEnd.hpp"
#include "compile/Compilation.hpp"
#include "compile/Method.hpp"
#include "compile/ResolvedMethod.hpp"
#include "compile/SymbolReferenceTable.hpp"
#include "compile/VirtualGuard.hpp"
#include "control/Options.hpp"
#include "control/Options_inlines.hpp"
#include "cs2/bitvectr.h"
#include "cs2/llistof.h"
#include "cs2/sparsrbit.h"
#include "env/CompilerEnv.hpp"
#include "env/ObjectModel.hpp"
#include "env/PersistentInfo.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/NodePool.hpp"
#include "il/Node_inlines.hpp"
#include "il/RegisterMappedSymbol.hpp"
#include "il/ResolvedMethodSymbol.hpp"
#include "il/StaticSymbol.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/Link.hpp"
#include "infra/List.hpp"
#include "infra/CfgEdge.hpp"
#include "infra/CfgNode.hpp"
#include "infra/ILWalk.hpp"
#include "infra/String.hpp"
#include "optimizer/Dominators.hpp"
#include "optimizer/LocalAnalysis.hpp"
#include "optimizer/LoopCanonicalizer.hpp"
#include "optimizer/Optimization.hpp"
#include "optimizer/Optimization_inlines.hpp"
#include "optimizer/Optimizations.hpp"
#include "optimizer/Optimizer.hpp"
#include "optimizer/RegisterCandidate.hpp"
#include "optimizer/Structure.hpp"
#include "optimizer/TransformUtil.hpp"
#include "optimizer/UseDefInfo.hpp"
#include "optimizer/ValueNumberInfo.hpp"
#include "optimizer/VPConstraint.hpp"
#include "ras/Debug.hpp"
#include "ras/DebugCounter.hpp"
#ifdef J9_PROJECT_SPECIFIC
#include "runtime/J9ValueProfiler.hpp"
#include "runtime/J9Profiler.hpp"
#include "env/PersistentCHTable.hpp"
#include "env/VMJ9.h"
#endif
#define DEFAULT_LOOP_LIMIT 100000000
#define MAX_SIZE_INCREASE_FACTOR 8
#define MAX_BLOCKS_THRESHOLD 200
#define MAX_NESTING_DEPTH 8
#define NORMAL_BLOCK_COUNT 100
#define NORMAL_NODE_COUNT 1000
//#define MIN_PROFILED_FREQUENCY (.75f)
#define OPT_DETAILS_LOOP_VERSIONER "O^O LOOP VERSIONER: "
const int HIGH_FREQ_THRESHOLD = 5000;
/*
void printNode(TR::Node *node, TR_BitVector &visitedNodes, int32_t indentation)
{
if (visitedNodes.isSet(node->getGlobalIndex()))
{
traceMsg(comp(), "\t\t\t%p %5d %*s ==>%s\n", node,
node->getLocalIndex(), indentation, " ",
comp()->getDebug()->getName(node->getOpCode()));
}
else
{
traceMsg(comp(), "\t\t\t%p %5d %*s %s %s\n", node,
node->getLocalIndex(),
indentation, " ", comp()->getDebug()->getName(node->getOpCode()),
node->getOpCode().hasSymbolReference() ?
comp()->getDebug()->getName(node->getSymbolReference()): "");
//comp()->getDebug()->printNodeInfo(comp()->getDebug()->getOutFile(), node);
visitedNodes.set(node->getGlobalIndex());
for (int32_t i = 0; i < node->getNumChildren(); ++i)
{
printNode(node->getChild(i), visitedNodes, indentation+2);
}
}
}
*/
TR_LoopSpecializer::TR_LoopSpecializer(TR::OptimizationManager *manager)
: TR_LoopVersioner(manager, true)
{}
const char *
TR_LoopSpecializer::optDetailString() const throw()
{
return "O^O LOOP SPECIALIZER: ";
}
TR_LoopVersioner::TR_LoopVersioner(TR::OptimizationManager *manager, bool onlySpecialize, bool refineAliases)
: TR_LoopTransformer(manager),
_versionableInductionVariables(trMemory()), _specialVersionableInductionVariables(trMemory()),
_derivedVersionableInductionVariables(trMemory()),
////_virtualGuardPairs(trMemory()),
_guardedCalls(trMemory()),
_refineLoopAliases(refineAliases),_addressingTooComplicated(false),
_visitedNodes(comp()->getNodeCount() /*an estimate*/, trMemory(), heapAlloc, growable),
_checksInDupHeader(trMemory()),
_exitGotoTarget(NULL),
_curLoop(NULL),
_invalidateAliasSets(false)
{
_nonInlineGuardConditionalsWillNotBeEliminated = false;
setOnlySpecializeLoops(onlySpecialize);
}
int32_t TR_LoopVersioner::perform()
{
if (!comp()->mayHaveLoops() || optimizer()->optsThatCanCreateLoopsDisabled())
return 0;
_postDominators = NULL;
return performWithoutDominators();
}
int32_t TR_LoopVersioner::performWithDominators()
{
if (trace())
traceMsg(comp(), "Building Control Dependencies\n");
TR_PostDominators postDominators(comp());
if (postDominators.isValid())
{
postDominators.findControlDependents();
_postDominators = &postDominators;
}
else
{
printf("WARNING: method may have infinite loops\n");
}
auto result = performWithoutDominators();
/* Local variable postDominators is about to go out of scope.
* NULL this field to prevent illegal access to a stack
* allocated object.
*/
_postDominators = NULL;
return result;
}
bool TR_LoopVersioner::loopIsWorthVersioning(TR_RegionStructure *naturalLoop)
{
TR::Block *entryBlock = naturalLoop->getEntryBlock();
if (entryBlock->isCold())
{
if (trace()) traceMsg(comp(), "loopIsWorthVersioning returning false for cold block\n");
return false;
}
// if aggressive loop versioner flag is set then run at any optlevel, otherwise only at warm or less
bool aggressive = comp()->getOption(TR_EnableAggressiveLoopVersioning);
if (aggressive || comp()->getMethodHotness() <= warm)
{
if (naturalLoop->getParent())
{
TR_StructureSubGraphNode *loopNode = naturalLoop->getParent()->findNodeInHierarchy(naturalLoop->getNumber());
if (loopNode && (loopNode->getPredecessors().size() == 1))
{
TR_StructureSubGraphNode *loopInvariantNode = toStructureSubGraphNode(loopNode->getPredecessors().front()->getFrom());
if (loopInvariantNode->getStructure()->asBlock() &&
loopInvariantNode->getStructure()->asBlock()->isLoopInvariantBlock())
{
TR::Block *loopInvariantBlock = loopInvariantNode->getStructure()->asBlock()->getBlock();
static const char *unimportantLoopCountStr = feGetEnv("TR_UnimportantLoopCountThreshold");
int32_t unimportantLoopCountThreshold = unimportantLoopCountStr ? atoi(unimportantLoopCountStr) : 2;
if ((unimportantLoopCountThreshold*loopInvariantBlock->getFrequency()) > entryBlock->getFrequency()) // loop does not even run twice
{
if (trace()) traceMsg(comp(), "loopIsWorthVersioning returning false based on LoopCountThreshold\n");
return false;
}
}
}
}
bool aggressive = comp()->getOption(TR_EnableAggressiveLoopVersioning);
int32_t lvBlockFreqCutoff;
static const char * b = feGetEnv("TR_LoopVersionerFreqCutoff");
if (b)
{
lvBlockFreqCutoff = atoi(b);
}
else if (aggressive)
{
lvBlockFreqCutoff = 500;
}
else
{
lvBlockFreqCutoff = 5000;
}
if (trace()) traceMsg(comp(), "lvBlockFreqCutoff=%d\n", lvBlockFreqCutoff);
if (entryBlock->getFrequency() < lvBlockFreqCutoff)
{
if (trace()) traceMsg(comp(), "loopIsWorthVersioning returning false based on lvBlockFreqCutoff\n");
return false;
}
}
if (trace()) traceMsg(comp(), "loopIsWorthVersioning returning true\n");
return true;
}
int32_t TR_LoopVersioner::performWithoutDominators()
{
_seenDefinedSymbolReferences = NULL;
_additionInfo = NULL;
_nullCheckReference = NULL;
_conditionalTree = NULL;
_duplicateConditionalTree = NULL;
_currentNaturalLoop = NULL;
_versionableInductionVariables.deleteAll();
_specialVersionableInductionVariables.deleteAll();
_derivedVersionableInductionVariables.deleteAll();
////_virtualGuardPairs.deleteAll();
_virtualGuardInfo.setFirst(NULL);
_containsGuard = false;
_containsUnguardedCall = false;
_counter = 0;
_inNullCheckReference = 0,
_containsCall = 0;
_neitherLoopCold = 0;
_loopConditionInvariant = 0;
_guardedCalls.deleteAll();
_loopTransferDone = false;
_origNodeCount = comp()->getAccurateNodeCount();
_origBlockCount = comp()->getFlowGraph()->getNodes().getSize();
_doingVersioning = true;
bool somethingChanged = false;
// From this point on stack memory allocations will die when the function returns
TR::StackMemoryRegion stackMemoryRegion(*trMemory());
initAdditionalDataStructures();
TR_ScratchList<TR::CFGNode> newEmptyBlocks(trMemory());
TR_ScratchList<TR::CFGNode> newEmptyExceptionBlocks(trMemory());
_cfg = comp()->getFlowGraph();
if (trace())
{
traceMsg(comp(), "Starting LoopVersioning\n");
traceMsg(comp(), "\nCFG before loop versioning:\n");
getDebug()->print(comp()->getOutFile(), _cfg);
}
// printTrees();
TR_ScratchList<TR_Structure> whileLoops(trMemory());
createWhileLoopsList(&whileLoops);
ListIterator<TR_Structure> whileLoopsIt(&whileLoops);
if (whileLoops.isEmpty())
{
return false;
}
TR_ScratchList<TR_Structure> innerWhileLoops(trMemory());
TR_ScratchList<TR_Structure> *curLoops = NULL;
int32_t curWeight = 10;
curLoops = &whileLoops;
bool needToPruneMore;
if (!comp()->getOption(TR_ProcessHugeMethods) &&
(whileLoops.getSize() > HIGH_LOOP_COUNT/2))
{
needToPruneMore = true;
while (needToPruneMore)
{
TR_Structure *nextWhileLoop;
ListElement<TR_Structure> *prevLoop = NULL;
ListIterator<TR_Structure> whileLoopsIt2(&whileLoops);
for (nextWhileLoop = whileLoopsIt2.getFirst(); nextWhileLoop != NULL; nextWhileLoop = whileLoopsIt2.getNext())
{
TR_RegionStructure *naturalLoop = nextWhileLoop->asRegion();
TR::Block *entryBlock = naturalLoop->getEntryBlock();
if (!entryBlock->isCold())
{
int32_t weight = 1;
entryBlock->getStructureOf()->calculateFrequencyOfExecution(&weight);
if (weight > curWeight)
prevLoop = innerWhileLoops.addAfter(naturalLoop, prevLoop);
}
}
if (innerWhileLoops.getSize() > HIGH_LOOP_COUNT/2)
{
curWeight = curWeight*10;
innerWhileLoops.deleteAll();
}
else
needToPruneMore = false;
}
curLoops = &innerWhileLoops;
}
bool enableSpecialization = false;
TR_Structure *nextWhileLoop;
// _startOfHeader originally points to the last tree in the method;
// this variable is used as a placeholder to keep track of where
// trees can be moved (sometimes required for efficiency purposes
// to minimize gotos in the critical 'hot' path between the loop body
// and the new duplicate header that drives the new Do While loop.
//
_startOfHeader = comp()->getMethodSymbol()->getLastTreeTop();
_seenDefinedSymbolReferences = new (trStackMemory()) TR_BitVector(comp()->getSymRefCount(), trMemory(), stackAlloc, growable);
_writtenAndNotJustForHeapification = new (trStackMemory()) TR_BitVector(comp()->getSymRefCount(), trMemory(), stackAlloc, growable);
_additionInfo = new (trStackMemory()) TR_BitVector(comp()->getSymRefCount(), trMemory(), stackAlloc, growable);
_whileIndex = 0;
_counter = 0;
_guardedCalls.deleteAll();
for (nextWhileLoop = whileLoopsIt.getFirst(); nextWhileLoop != NULL; nextWhileLoop = whileLoopsIt.getNext())
{
// Can be used for debugging; to stop a particular loop from being
// and see if the problem persists or not.
//
//if (_counter == 1)
// break;
//else
// _counter++;
TR_RegionStructure *naturalLoop = nextWhileLoop->asRegion();
// HCR guard versioning removes edges from the CFG immediately (unlike
// versioning of regular conditionals/virtual guards, which leaves a
// trivially foldable conditional tree in place). The removal of
// particular edges can change loops into acyclic regions, so skip any
// region that is no longer a loop.
//
// (OSR guard versioning also removes edges immediately, but the targets
// of those edges are not within any loop, so their removal can't change
// loops into acyclic regions.)
//
if (!naturalLoop->isNaturalLoop())
continue;
TR::Block *entryBlock = naturalLoop->getEntryBlock();
if (!loopIsWorthVersioning(naturalLoop))
continue;
_requiresAdditionalCheckForIncrement = false;
_neitherLoopCold = false;
_containsGuard = false;
_containsUnguardedCall = false;
_loopTransferDone = false;
_unchangedValueUsedInBndCheck = new(trStackMemory()) TR_BitVector(comp()->getNodeCount(), trMemory(), stackAlloc);
_checksInDupHeader.deleteAll();
TR_ASSERT(naturalLoop && naturalLoop->isNaturalLoop(),"Loop versioner, expecting natural loop");
if (trace())
comp()->dumpMethodTrees("Trees after this versioning");
TR::Region curLoopMemRegion(stackMemoryRegion);
CurLoop curLoop(comp(), curLoopMemRegion, naturalLoop);
_curLoop = &curLoop;
TR_ScratchList<TR::Node> nullCheckedReferences(trMemory());
TR_ScratchList<TR::TreeTop> nullCheckTrees(trMemory());
TR_ScratchList<int32_t> numIndirections(trMemory());
TR_ScratchList<TR::TreeTop> boundCheckTrees(trMemory());
TR_ScratchList<TR::TreeTop> spineCheckTrees(trMemory());
TR_ScratchList<int32_t> numDimensions(trMemory());
TR_ScratchList<TR::TreeTop> conditionalTrees(trMemory());
TR_ScratchList<TR::TreeTop> divCheckTrees(trMemory());
TR_ScratchList<TR::TreeTop> checkCastTrees(trMemory());
TR_ScratchList<TR::TreeTop> arrayStoreCheckTrees(trMemory());
TR_ScratchList<TR::TreeTop> awrtbariTrees(trMemory());
TR_ScratchList<TR::Node> specializedInvariantNodes(trMemory());
TR_ScratchList<TR_NodeParentSymRef> invariantNodesList(trMemory());
TR_ScratchList<TR_NodeParentSymRefWeightTuple> invariantTranslationNodesList(trMemory());
TR_ScratchList<TR::Node> arrayAccesses(trMemory());
TR_ScratchList<TR_NodeParentBlockTuple> arrayLoadCandidates(trMemory());
TR_ScratchList<TR_NodeParentBlockTuple> arrayMemberLoadCandidates(trMemory());
TR_BitVector disqualifiedRefinementCandidates(1,trMemory(),stackAlloc,growable);
_disqualifiedRefinementCandidates = & disqualifiedRefinementCandidates;
_arrayLoadCandidates = &arrayLoadCandidates;
_arrayAccesses = &arrayAccesses;
_arrayMemberLoadCandidates = &arrayMemberLoadCandidates;
_currentNaturalLoop = naturalLoop;
List<TR_NodeParentSymRef> *invariantNodes = &invariantNodesList;
if (comp()->getOption(TR_DisableInvariantCodeMotion) || shouldOnlySpecializeLoops())
invariantNodes = NULL;
if (refineAliases())
{
naturalLoop->resetInvariance();
naturalLoop->computeInvariantExpressions();
}
_seenDefinedSymbolReferences->empty();
_writtenAndNotJustForHeapification->empty();
_additionInfo->empty();
_asyncCheckTree = NULL;
// Initialize induction variable information
//
_numberOfTreesInLoop = 0;
_versionableInductionVariables.deleteAll();
_specialVersionableInductionVariables.deleteAll();
_derivedVersionableInductionVariables.deleteAll();
if(detectCanonicalizedPredictableLoops(naturalLoop, NULL, -1)<0) //if there was a problem detecting, move to next iteration of the loop
{
_curLoop = NULL;
continue;
}
_loopConditionInvariant = false;
bool discontinue = false;
bool nullChecksMayBeEliminated = detectChecksToBeEliminated(naturalLoop, &nullCheckedReferences, &nullCheckTrees, &numIndirections,
&boundCheckTrees, &spineCheckTrees, &numDimensions, &conditionalTrees, &divCheckTrees, &awrtbariTrees,
&checkCastTrees, &arrayStoreCheckTrees, &specializedInvariantNodes, invariantNodes,
&invariantTranslationNodesList, discontinue);
if (discontinue)
{
_curLoop = NULL;
continue;
}
if (_loopTestTree)
{
if ((_loopTestTree->getNode()->getNumChildren() > 1) &&
isExprInvariant(_loopTestTree->getNode()->getSecondChild()))
{
if (trace())
traceMsg(comp(), "Limit in loop test tree %p is invariant\n", _loopTestTree->getNode()->getSecondChild());
_loopConditionInvariant = true;
}
else
_asyncCheckTree = NULL;
}
else
_asyncCheckTree = NULL;
bool nullChecksWillBeEliminated = false;
if (nullChecksMayBeEliminated &&
!refineAliases() &&
!shouldOnlySpecializeLoops())
nullChecksWillBeEliminated = detectInvariantChecks(&nullCheckedReferences, &nullCheckTrees);
else
{
//nullCheckTrees.deleteAll();
//nullCheckedReferences.deleteAll();
}
bool specializedNodesWillBeEliminated = false;
if(!refineAliases())
specializedNodesWillBeEliminated = detectInvariantSpecializedExprs(&specializedInvariantNodes);
else
specializedInvariantNodes.deleteAll();
bool skipAsyncCheckRemoval = false;
if (!shouldOnlySpecializeLoops() && !refineAliases())
{
specializedNodesWillBeEliminated = false;
if (!specializedInvariantNodes.isEmpty())
{
enableSpecialization = true;
skipAsyncCheckRemoval = true;
}
specializedInvariantNodes.deleteAll();
}
bool invariantNodesWillBeEliminated = false;
if (!refineAliases() && invariantNodes && !invariantNodes->isEmpty())
invariantNodesWillBeEliminated = detectInvariantNodes(invariantNodes, &invariantTranslationNodesList);
else
{
invariantTranslationNodesList.deleteAll();
invariantNodesList.deleteAll();
}
bool boundChecksWillBeEliminated = false;
if (!shouldOnlySpecializeLoops() && !refineAliases())
boundChecksWillBeEliminated = detectInvariantBoundChecks(&boundCheckTrees);
else
boundCheckTrees.deleteAll();
bool spineChecksWillBeEliminated = false;
if (false && shouldOnlySpecializeLoops() && comp()->requiresSpineChecks() && !refineAliases())
spineChecksWillBeEliminated = detectInvariantSpineChecks(&spineCheckTrees);
else
spineCheckTrees.deleteAll();
bool divChecksWillBeEliminated = false;
if (!shouldOnlySpecializeLoops() && !refineAliases())
divChecksWillBeEliminated = detectInvariantDivChecks(&divCheckTrees);
//else
// divCheckTrees.deleteAll();
bool awrtBarisWillBeEliminated = false;
if (!shouldOnlySpecializeLoops() && !refineAliases())
awrtBarisWillBeEliminated = detectInvariantAwrtbaris(&awrtbariTrees);
else
awrtbariTrees.deleteAll();
SharedSparseBitVector reverseBranchInLoops(comp()->allocator());
bool checkCastTreesWillBeEliminated = false;
if (!shouldOnlySpecializeLoops() && !refineAliases())
checkCastTreesWillBeEliminated = detectInvariantCheckCasts(&checkCastTrees);
else
checkCastTrees.deleteAll();
bool arrayStoreCheckTreesWillBeEliminated = false;
if (!shouldOnlySpecializeLoops() && !refineAliases())
arrayStoreCheckTreesWillBeEliminated = detectInvariantArrayStoreChecks(&arrayStoreCheckTrees);
else
arrayStoreCheckTrees.deleteAll();
bool conditionalsWillBeEliminated = false;
bool versionToRefineAliases = false;
if(refineAliases())
versionToRefineAliases = processArrayAliasCandidates();
_conditionalTree = NULL;
_duplicateConditionalTree = NULL;
bool containsNonInlineGuard = false;
if (!shouldOnlySpecializeLoops() && !refineAliases())
{
// default hotness threshold
TR_Hotness hotnessThreshold = hot;
if (comp()->getOption(TR_EnableAggressiveLoopVersioning))
{
if (trace()) traceMsg(comp(), "aggressiveLoopVersioning: raising hotnessThreshold for conditionalsWillBeEliminated\n");
hotnessThreshold = maxHotness; // threshold which can't be matched by the > operator
}
if (( (debug("nullCheckVersion") ||
comp()->cg()->performsChecksExplicitly() ||
(comp()->getMethodHotness() > hotnessThreshold)
) && nullChecksWillBeEliminated
) ||
boundChecksWillBeEliminated ||
divChecksWillBeEliminated ||
awrtBarisWillBeEliminated ||
checkCastTreesWillBeEliminated ||
arrayStoreCheckTreesWillBeEliminated ||
specializedNodesWillBeEliminated ||
invariantNodesWillBeEliminated ||
_nonInlineGuardConditionalsWillNotBeEliminated ||
_loopTransferDone)
{
conditionalsWillBeEliminated = detectInvariantConditionals(
naturalLoop,
&conditionalTrees,
true,
&containsNonInlineGuard,
reverseBranchInLoops);
}
else
{
conditionalsWillBeEliminated = detectInvariantConditionals(
naturalLoop,
&conditionalTrees,
false,
&containsNonInlineGuard,
reverseBranchInLoops);
if (containsNonInlineGuard)
{
_neitherLoopCold = true;
_conditionalTree = conditionalTrees.getListHead()->getData()->getNode();
}
}
}
else
{
conditionalTrees.deleteAll();
_neitherLoopCold = true;
}
List<TR_Structure> clonedInnerWhileLoops(trMemory());
bool versionedThisLoop = false;
if ((versionToRefineAliases || !refineAliases()) &&
(((debug("nullCheckVersion") || comp()->cg()->performsChecksExplicitly() ||
(comp()->getMethodHotness() >= veryHot)) &&
(naturalLoop->containsOnlyAcyclicRegions() || !_loopTransferDone) &&
nullChecksWillBeEliminated) ||
(_asyncCheckTree &&
shouldOnlySpecializeLoops()) ||
boundChecksWillBeEliminated ||
spineChecksWillBeEliminated ||
conditionalsWillBeEliminated ||
divChecksWillBeEliminated ||
awrtBarisWillBeEliminated ||
checkCastTreesWillBeEliminated ||
arrayStoreCheckTreesWillBeEliminated ||
specializedNodesWillBeEliminated ||
invariantNodesWillBeEliminated ||
versionToRefineAliases ||
_containsGuard))
{
//if (shouldOnlySpecializeLoops())
// printf("Reached here for %s\n", comp()->signature());
somethingChanged = true;
versionedThisLoop = true;
versionNaturalLoop(naturalLoop, &nullCheckedReferences, &nullCheckTrees, &boundCheckTrees, &spineCheckTrees, &conditionalTrees, &divCheckTrees, &awrtbariTrees, &checkCastTrees, &arrayStoreCheckTrees, &specializedInvariantNodes, invariantNodes, &invariantTranslationNodesList, &whileLoops, &clonedInnerWhileLoops, skipAsyncCheckRemoval, reverseBranchInLoops);
_exitGotoTarget = NULL;
}
if (versionedThisLoop)
{
int32_t symRefCount = comp()->getSymRefCount();
TR::SymbolReferenceTable *symRefTab = comp()->getSymRefTab();
if(refineAliases())
refineArrayAliases(naturalLoop);
TR_BitVector *inductionVars = new (trStackMemory()) TR_BitVector(symRefCount, trMemory(), stackAlloc);
ListElement<int32_t> *versionableInductionVar = _versionableInductionVariables.getListHead();
while (versionableInductionVar)
{
TR::SymbolReference *inductionVar = comp()->getSymRefTab()->getSymRef(*(versionableInductionVar->getData()));
//printf("Induction variable %d in loop %d in register for %s\n", inductionVar->getReferenceNumber(), naturalLoop->getNumber(), comp()->signature());
inductionVars->set(inductionVar->getReferenceNumber());
TR::RegisterCandidate *inductionCandidate = comp()->getGlobalRegisterCandidates()->findOrCreate(inductionVar);
//dumpOptDetails(comp(), "%s Adding auto %d as a global register candidate in loop %d\n", OPT_DETAILS_LOOP_VERSIONER, inductionCandidate->getSymbolReference()->getReferenceNumber(), naturalLoop->getNumber());
inductionCandidate->addAllBlocksInStructure(naturalLoop, comp(), trace()?"auto":NULL);
versionableInductionVar = versionableInductionVar->getNextElement();
}
TR_InductionVariable *v;
int32_t symRefNumber;
for (v = naturalLoop->getFirstInductionVariable(); v; v = v->getNext())
{
TR::SymbolReference *symRef = NULL;
TR::SymbolReference *inductionSymRef = NULL;
for (symRefNumber = symRefTab->getIndexOfFirstSymRef(); symRefNumber < symRefCount; symRefNumber++)
{
symRef = symRefTab->getSymRef(symRefNumber);
if (symRef)
{
TR::Symbol *sym = symRef->getSymbol();
if (v->getLocal() == sym)
{
inductionSymRef = symRef;
break;
}
}
}
if (inductionSymRef && !inductionVars->get(inductionSymRef->getReferenceNumber()))
{
//printf("CP Induction variable %d in natural loop %d in register for %s\n", inductionSymRef->getReferenceNumber(), naturalLoop->getNumber(), comp()->signature());
TR::RegisterCandidate *inductionCandidate = comp()->getGlobalRegisterCandidates()->findOrCreate(inductionSymRef);
//dumpOptDetails(comp(), "%s Adding auto %d as a global register candidate in loop %d\n", OPT_DETAILS_LOOP_VERSIONER, inductionCandidate->getSymbolReference()->getReferenceNumber(), naturalLoop->getNumber());
inductionCandidate->addAllBlocksInStructure(naturalLoop, comp(), trace()?"auto":NULL);
}
}
whileLoops.setListHead(whileLoopsIt.getCurrentElement());
clonedInnerWhileLoops.popHead();
ListIterator<TR_Structure> clonedInnerWhileLoopsIt(&clonedInnerWhileLoops);
TR_Structure *clonedInnerWhileLoop = clonedInnerWhileLoopsIt.getFirst();
ListElement<TR_Structure> *prevClonedInnerLoop = whileLoops.getListHead();
for (; clonedInnerWhileLoop != NULL; clonedInnerWhileLoop = clonedInnerWhileLoopsIt.getNext())
{
prevClonedInnerLoop = whileLoops.addAfter(clonedInnerWhileLoop, prevClonedInnerLoop);
}
whileLoopsIt.set(&whileLoops);
if (!shouldOnlySpecializeLoops() && !refineAliases() && comp()->requiresSpineChecks())
{
if (!spineCheckTrees.isEmpty())
{
enableSpecialization = true;
skipAsyncCheckRemoval = true;
}
}
}
_curLoop = NULL;
}
// If there are any entries in _virtualGuardInfo, they were taken into
// account in the above analyses (i.e. their cold calls were assumed to have
// been removed from the loop after transformation), so at this point loop
// transfer is mandatory.
if (!_virtualGuardInfo.isEmpty())
performLoopTransfer();
// Use/def info and value number info are now bad.
//
optimizer()->setUseDefInfo(NULL);
optimizer()->setValueNumberInfo(NULL);
_nonInlineGuardConditionalsWillNotBeEliminated = true;
if (!shouldOnlySpecializeLoops() &&
enableSpecialization)
{
//setOnlySpecializeLoops(true);
requestOpt(OMR::loopSpecializerGroup);
}
else if (shouldOnlySpecializeLoops())
{
//setOnlySpecializeLoops(false);
requestOpt(OMR::deadTreesElimination);
requestOpt(OMR::treeSimplification);
}
if (somethingChanged)
requestOpt(OMR::andSimplification);
if (trace())
{
traceMsg(comp(), "\nCFG after loop versioning:\n");
getDebug()->print(comp()->getOutFile(), _cfg);
traceMsg(comp(), "Ending LoopVersioner\n");
}
//comp()->dumpMethodTrees("Trees after this versioning");
if (_invalidateAliasSets)
optimizer()->setAliasSetsAreValid(false);
return 1; // actual cost
}
void TR_LoopVersioner::performLoopTransfer()
{
// Only do the transfer if there are no unguarded calls left
// in the loop (should be checked here)
//
dumpOptDetails(comp(), "Loop transfer in %s with size %d\n", comp()->signature(), _virtualGuardInfo.getSize());
TR_ScratchList<TR::Node> processedVirtualGuards(trMemory());
TR::CFG *cfg = comp()->getFlowGraph();
VirtualGuardInfo *vgInfo = NULL;
for (vgInfo = _virtualGuardInfo.getFirst(); vgInfo; vgInfo = vgInfo->getNext())
{
ListIterator<VirtualGuardPair> guardsIt(&vgInfo->_virtualGuardPairs);
VirtualGuardPair *nextVirtualGuard;
for (nextVirtualGuard = guardsIt.getFirst(); nextVirtualGuard != NULL; nextVirtualGuard = guardsIt.getNext())
{
TR::Block *hotGuardBlock = nextVirtualGuard->_hotGuardBlock;
TR::Block *coldGuardBlock = nextVirtualGuard->_coldGuardBlock;
TR::TreeTop *hotGuardTree = hotGuardBlock->getLastRealTreeTop();
TR::TreeTop *coldGuardTree = coldGuardBlock->getLastRealTreeTop();
TR::Node *hotGuard = hotGuardTree->getNode();
TR::Node *coldGuard = coldGuardTree->getNode();
if (hotGuard->getOpCode().isIf() &&
hotGuard->isTheVirtualGuardForAGuardedInlinedCall() &&
coldGuard->getOpCode().isIf() &&
coldGuard->isTheVirtualGuardForAGuardedInlinedCall())
{
// Can set up loop transfer now
//
cfg->setStructure(NULL);
hotGuardBlock->changeBranchDestination(coldGuard->getBranchDestination(), cfg);
dumpOptDetails(comp(), "loop transfer, changed target of guard [%p] in [%d] to [%d]\n", hotGuard, hotGuardBlock->getNumber(), coldGuard->getBranchDestination()->getNode()->getBlock()->getNumber());
const char *debugCounter = TR::DebugCounter::debugCounterName(comp(), "loopVersioner.transfer/(%s)/%s/origin=block_%d", comp()->signature(), comp()->getHotnessName(comp()->getMethodHotness()), hotGuardBlock->getNumber());
if (comp()->getOptions()->dynamicDebugCounterIsEnabled(debugCounter))
{
TR::Block *newBlock = hotGuardBlock->splitEdge(hotGuardBlock, coldGuard->getBranchDestination()->getNode()->getBlock(), comp(), NULL, false);
TR::DebugCounter::prependDebugCounter(comp(), debugCounter, newBlock->getEntry()->getNextTreeTop());
}
}
}
}
}
// create the switch block containing the node
// and return the cloned header of the loop
//
TR::Block *TR_LoopVersioner::createClonedHeader(TR::Block *origHeader, TR::TreeTop **endTree)
{
TR_BlockCloner cloner(_cfg, true);
TR::Block *clonedHeader = cloner.cloneBlocks(origHeader, origHeader);
clonedHeader->setFrequency(origHeader->getFrequency());
if (origHeader->getNextBlock())
clonedHeader->getExit()->join(origHeader->getNextBlock()->getEntry());
else
{
// update the endTree
clonedHeader->getExit()->setNextTreeTop(NULL);
*endTree = clonedHeader->getExit();
}
origHeader->getExit()->join(clonedHeader->getEntry());
TR_ScratchList<TR::CFGEdge> removedEdges(trMemory());
// fixup the successors
//
for (auto e = origHeader->getSuccessors().begin(); e != origHeader->getSuccessors().end(); ++e)
{
removedEdges.add(*e);
TR::Block *dest = toBlock((*e)->getTo());
_cfg->addEdge(TR::CFGEdge::createEdge(clonedHeader, dest, trMemory()));
}
for (auto e = origHeader->getExceptionSuccessors().begin(); e != origHeader->getExceptionSuccessors().end(); ++e)
{
removedEdges.add(*e);
TR::Block *dest = toBlock((*e)->getTo());
_cfg->addEdge(TR::CFGEdge::createExceptionEdge(clonedHeader, dest,trMemory()));
}
_cfg->addEdge(TR::CFGEdge::createEdge(origHeader, clonedHeader, trMemory()));
// now remove the edges
//
ListIterator<TR::CFGEdge> sIt;
sIt.set(&removedEdges);
for (TR::CFGEdge* e = sIt.getFirst(); e; e = sIt.getNext())
_cfg->removeEdge(e);
return clonedHeader;
}
TR::Node *TR_LoopVersioner::createSwitchNode(TR::Block *clonedHeader, TR::SymbolReference *tempSymRef, int32_t numCase)
{
TR::Node *switchNode = TR::Node::create(clonedHeader->getFirstRealTreeTop()->getNode(), TR::lookup, numCase+2);
TR::Node *loadTemp = TR::Node::createWithSymRef(switchNode, TR::iload, 0, tempSymRef);
switchNode->setAndIncChild(0, loadTemp);
for (int32_t i = 0; i < numCase+1; i++)
{
TR::Node *caseNode = TR::Node::createCase(switchNode, clonedHeader->getEntry(), i);
switchNode->setAndIncChild(i+1, caseNode);
}
return switchNode;
}
TR::Block * TR_LoopVersioner::createEmptyGoto(TR::Block *source, TR::Block *dest, TR::TreeTop *endTree)
{
// create an empty goto block
// its the caller's responsibility to add this block to the cfg
// and create appropriate edges
//
TR::TreeTop *destEntry = dest->getEntry();
TR::Block *gotoBlock = TR::Block::createEmptyBlock(destEntry->getNode(), comp(), dest->getFrequency(), dest);
gotoBlock->setIsSpecialized(dest->isSpecialized());
TR::TreeTop *gotoEntry = gotoBlock->getEntry();
TR::TreeTop *gotoExit = gotoBlock->getExit();
TR::Node *gotoNode = TR::Node::create(destEntry->getNextTreeTop()->getNode(), TR::Goto, 0, destEntry);
TR::TreeTop *gotoTree = TR::TreeTop::create(comp(), gotoNode);
gotoEntry->join(gotoTree);
gotoTree->join(gotoExit);
// paste the block in the trees
// if endTree is null, caller will
// take care of pasting
//
if (endTree)
{
endTree->join(gotoEntry);
gotoExit->setNextTreeTop(NULL);
}
gotoEntry->getNode()->setBlock(gotoBlock);
gotoExit->getNode()->setBlock(gotoBlock);
return gotoBlock;
}
bool TR_LoopVersioner::detectInvariantChecks(List<TR::Node> *nullCheckedReferences, List<TR::TreeTop> *nullCheckTrees)
{
bool foundInvariantChecks = false;
ListElement<TR::Node> *node, *prevNode = NULL;
ListElement<TR::TreeTop> *nextTree = nullCheckTrees->getListHead();
ListElement<TR::TreeTop> *prevTree = NULL;
for (node = nullCheckedReferences->getListHead(); node != NULL;)
{
bool isNullCheckReferenceInvariant = isExprInvariant(node->getData());
if (!isNullCheckReferenceInvariant &&
node->getData()->getOpCode().hasSymbolReference() &&
((node->getData()->getSymbolReference()->getSymbol()->isAuto() && isDependentOnInvariant(node->getData())) ||
(node->getData()->getOpCode().isLoadIndirect() &&
!_seenDefinedSymbolReferences->get(node->getData()->getSymbolReference()->getReferenceNumber()) &&
node->getData()->getFirstChild()->getOpCode().hasSymbolReference() &&
node->getData()->getFirstChild()->getSymbolReference()->getSymbol()->isAuto() &&
isDependentOnInvariant(node->getData()->getFirstChild()))))
isNullCheckReferenceInvariant = true;
if (!isNullCheckReferenceInvariant ||
_checksInDupHeader.find(nextTree->getData()))
{
if (trace())
traceMsg(comp(), "Non invariant Null check reference %p (%s)\n", node->getData(), node->getData()->getOpCode().getName());
if (prevNode)
{
prevNode->setNextElement(node->getNextElement());
prevTree->setNextElement(nextTree->getNextElement());
}
else
{
nullCheckedReferences->setListHead(node->getNextElement());
nullCheckTrees->setListHead(nextTree->getNextElement());
}
}
else
{
if (trace())
traceMsg(comp(), "Invariant Null check reference %p (%s)\n", node->getData(), node->getData()->getOpCode().getName());
foundInvariantChecks = true;
prevNode = node;
prevTree = nextTree;
}
node = node->getNextElement();
nextTree = nextTree->getNextElement();
}
return foundInvariantChecks;
}