| /* |
| * Copyright (c) 2009, 2015, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| package org.graalvm.compiler.lir.alloc.lsra; |
| |
| import static org.graalvm.compiler.lir.LIRValueUtil.isStackSlotValue; |
| import static org.graalvm.compiler.lir.LIRValueUtil.isVariable; |
| import static jdk.vm.ci.code.CodeUtil.isOdd; |
| import static jdk.vm.ci.code.ValueUtil.asRegister; |
| import static jdk.vm.ci.code.ValueUtil.isRegister; |
| |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.List; |
| |
| import org.graalvm.compiler.core.common.alloc.RegisterAllocationConfig.AllocatableRegisters; |
| import org.graalvm.compiler.core.common.cfg.AbstractBlockBase; |
| import org.graalvm.compiler.core.common.util.Util; |
| import org.graalvm.compiler.debug.Debug; |
| import org.graalvm.compiler.debug.GraalError; |
| import org.graalvm.compiler.debug.Indent; |
| import org.graalvm.compiler.lir.LIRInstruction; |
| import org.graalvm.compiler.lir.StandardOp.ValueMoveOp; |
| import org.graalvm.compiler.lir.alloc.OutOfRegistersException; |
| import org.graalvm.compiler.lir.alloc.lsra.Interval.RegisterBinding; |
| import org.graalvm.compiler.lir.alloc.lsra.Interval.RegisterPriority; |
| import org.graalvm.compiler.lir.alloc.lsra.Interval.SpillState; |
| import org.graalvm.compiler.lir.alloc.lsra.Interval.State; |
| |
| import jdk.vm.ci.code.Register; |
| import jdk.vm.ci.meta.Value; |
| |
| /** |
| */ |
| class LinearScanWalker extends IntervalWalker { |
| |
| protected Register[] availableRegs; |
| |
| protected final int[] usePos; |
| protected final int[] blockPos; |
| |
| protected List<Interval>[] spillIntervals; |
| |
| private MoveResolver moveResolver; // for ordering spill moves |
| |
| private int minReg; |
| |
| private int maxReg; |
| |
| /** |
| * Only 10% of the lists in {@link #spillIntervals} are actually used. But when they are used, |
| * they can grow quite long. The maximum length observed was 45 (all numbers taken from a |
| * bootstrap run of Graal). Therefore, we initialize {@link #spillIntervals} with this marker |
| * value, and allocate a "real" list only on demand in {@link #setUsePos}. |
| */ |
| private static final List<Interval> EMPTY_LIST = new ArrayList<>(0); |
| |
| // accessors mapped to same functions in class LinearScan |
| int blockCount() { |
| return allocator.blockCount(); |
| } |
| |
| AbstractBlockBase<?> blockAt(int idx) { |
| return allocator.blockAt(idx); |
| } |
| |
| AbstractBlockBase<?> blockOfOpWithId(int opId) { |
| return allocator.blockForId(opId); |
| } |
| |
| LinearScanWalker(LinearScan allocator, Interval unhandledFixedFirst, Interval unhandledAnyFirst) { |
| super(allocator, unhandledFixedFirst, unhandledAnyFirst); |
| |
| moveResolver = allocator.createMoveResolver(); |
| spillIntervals = Util.uncheckedCast(new List<?>[allocator.getRegisters().size()]); |
| for (int i = 0; i < allocator.getRegisters().size(); i++) { |
| spillIntervals[i] = EMPTY_LIST; |
| } |
| usePos = new int[allocator.getRegisters().size()]; |
| blockPos = new int[allocator.getRegisters().size()]; |
| } |
| |
| void initUseLists(boolean onlyProcessUsePos) { |
| for (Register register : availableRegs) { |
| int i = register.number; |
| usePos[i] = Integer.MAX_VALUE; |
| |
| if (!onlyProcessUsePos) { |
| blockPos[i] = Integer.MAX_VALUE; |
| spillIntervals[i].clear(); |
| } |
| } |
| } |
| |
| int maxRegisterNumber() { |
| return maxReg; |
| } |
| |
| int minRegisterNumber() { |
| return minReg; |
| } |
| |
| boolean isRegisterInRange(int reg) { |
| return reg >= minRegisterNumber() && reg <= maxRegisterNumber(); |
| } |
| |
| void excludeFromUse(Interval i) { |
| Value location = i.location(); |
| int i1 = asRegister(location).number; |
| if (isRegisterInRange(i1)) { |
| usePos[i1] = 0; |
| } |
| } |
| |
| void setUsePos(Interval interval, int usePos, boolean onlyProcessUsePos) { |
| if (usePos != -1) { |
| assert usePos != 0 : "must use excludeFromUse to set usePos to 0"; |
| int i = asRegister(interval.location()).number; |
| if (isRegisterInRange(i)) { |
| if (this.usePos[i] > usePos) { |
| this.usePos[i] = usePos; |
| } |
| if (!onlyProcessUsePos) { |
| List<Interval> list = spillIntervals[i]; |
| if (list == EMPTY_LIST) { |
| list = new ArrayList<>(2); |
| spillIntervals[i] = list; |
| } |
| list.add(interval); |
| } |
| } |
| } |
| } |
| |
| void setBlockPos(Interval i, int blockPos) { |
| if (blockPos != -1) { |
| int reg = asRegister(i.location()).number; |
| if (isRegisterInRange(reg)) { |
| if (this.blockPos[reg] > blockPos) { |
| this.blockPos[reg] = blockPos; |
| } |
| if (usePos[reg] > blockPos) { |
| usePos[reg] = blockPos; |
| } |
| } |
| } |
| } |
| |
| void freeExcludeActiveFixed() { |
| Interval interval = activeLists.get(RegisterBinding.Fixed); |
| while (interval != Interval.EndMarker) { |
| assert isRegister(interval.location()) : "active interval must have a register assigned"; |
| excludeFromUse(interval); |
| interval = interval.next; |
| } |
| } |
| |
| void freeExcludeActiveAny() { |
| Interval interval = activeLists.get(RegisterBinding.Any); |
| while (interval != Interval.EndMarker) { |
| assert isRegister(interval.location()) : "active interval must have a register assigned"; |
| excludeFromUse(interval); |
| interval = interval.next; |
| } |
| } |
| |
| void freeCollectInactiveFixed(Interval current) { |
| Interval interval = inactiveLists.get(RegisterBinding.Fixed); |
| while (interval != Interval.EndMarker) { |
| if (current.to() <= interval.currentFrom()) { |
| assert interval.currentIntersectsAt(current) == -1 : "must not intersect"; |
| setUsePos(interval, interval.currentFrom(), true); |
| } else { |
| setUsePos(interval, interval.currentIntersectsAt(current), true); |
| } |
| interval = interval.next; |
| } |
| } |
| |
| void freeCollectInactiveAny(Interval current) { |
| Interval interval = inactiveLists.get(RegisterBinding.Any); |
| while (interval != Interval.EndMarker) { |
| setUsePos(interval, interval.currentIntersectsAt(current), true); |
| interval = interval.next; |
| } |
| } |
| |
| void freeCollectUnhandled(RegisterBinding kind, Interval current) { |
| Interval interval = unhandledLists.get(kind); |
| while (interval != Interval.EndMarker) { |
| setUsePos(interval, interval.intersectsAt(current), true); |
| if (kind == RegisterBinding.Fixed && current.to() <= interval.from()) { |
| setUsePos(interval, interval.from(), true); |
| } |
| interval = interval.next; |
| } |
| } |
| |
| void spillExcludeActiveFixed() { |
| Interval interval = activeLists.get(RegisterBinding.Fixed); |
| while (interval != Interval.EndMarker) { |
| excludeFromUse(interval); |
| interval = interval.next; |
| } |
| } |
| |
| void spillBlockUnhandledFixed(Interval current) { |
| Interval interval = unhandledLists.get(RegisterBinding.Fixed); |
| while (interval != Interval.EndMarker) { |
| setBlockPos(interval, interval.intersectsAt(current)); |
| interval = interval.next; |
| } |
| } |
| |
| void spillBlockInactiveFixed(Interval current) { |
| Interval interval = inactiveLists.get(RegisterBinding.Fixed); |
| while (interval != Interval.EndMarker) { |
| if (current.to() > interval.currentFrom()) { |
| setBlockPos(interval, interval.currentIntersectsAt(current)); |
| } else { |
| assert interval.currentIntersectsAt(current) == -1 : "invalid optimization: intervals intersect"; |
| } |
| |
| interval = interval.next; |
| } |
| } |
| |
| void spillCollectActiveAny(RegisterPriority registerPriority) { |
| Interval interval = activeLists.get(RegisterBinding.Any); |
| while (interval != Interval.EndMarker) { |
| setUsePos(interval, Math.min(interval.nextUsage(registerPriority, currentPosition), interval.to()), false); |
| interval = interval.next; |
| } |
| } |
| |
| void spillCollectInactiveAny(Interval current) { |
| Interval interval = inactiveLists.get(RegisterBinding.Any); |
| while (interval != Interval.EndMarker) { |
| if (interval.currentIntersects(current)) { |
| setUsePos(interval, Math.min(interval.nextUsage(RegisterPriority.LiveAtLoopEnd, currentPosition), interval.to()), false); |
| } |
| interval = interval.next; |
| } |
| } |
| |
| void insertMove(int operandId, Interval srcIt, Interval dstIt) { |
| // output all moves here. When source and target are equal, the move is |
| // optimized away later in assignRegNums |
| |
| int opId = (operandId + 1) & ~1; |
| AbstractBlockBase<?> opBlock = allocator.blockForId(opId); |
| assert opId > 0 && allocator.blockForId(opId - 2) == opBlock : "cannot insert move at block boundary"; |
| |
| // calculate index of instruction inside instruction list of current block |
| // the minimal index (for a block with no spill moves) can be calculated because the |
| // numbering of instructions is known. |
| // When the block already contains spill moves, the index must be increased until the |
| // correct index is reached. |
| List<LIRInstruction> instructions = allocator.getLIR().getLIRforBlock(opBlock); |
| int index = (opId - instructions.get(0).id()) >> 1; |
| assert instructions.get(index).id() <= opId : "error in calculation"; |
| |
| while (instructions.get(index).id() != opId) { |
| index++; |
| assert 0 <= index && index < instructions.size() : "index out of bounds"; |
| } |
| assert 1 <= index && index < instructions.size() : "index out of bounds"; |
| assert instructions.get(index).id() == opId : "error in calculation"; |
| |
| // insert new instruction before instruction at position index |
| moveResolver.moveInsertPosition(instructions, index); |
| moveResolver.addMapping(srcIt, dstIt); |
| } |
| |
| int findOptimalSplitPos(AbstractBlockBase<?> minBlock, AbstractBlockBase<?> maxBlock, int maxSplitPos) { |
| int fromBlockNr = minBlock.getLinearScanNumber(); |
| int toBlockNr = maxBlock.getLinearScanNumber(); |
| |
| assert 0 <= fromBlockNr && fromBlockNr < blockCount() : "out of range"; |
| assert 0 <= toBlockNr && toBlockNr < blockCount() : "out of range"; |
| assert fromBlockNr < toBlockNr : "must cross block boundary"; |
| |
| // Try to split at end of maxBlock. If this would be after |
| // maxSplitPos, then use the begin of maxBlock |
| int optimalSplitPos = allocator.getLastLirInstructionId(maxBlock) + 2; |
| if (optimalSplitPos > maxSplitPos) { |
| optimalSplitPos = allocator.getFirstLirInstructionId(maxBlock); |
| } |
| |
| int minLoopDepth = maxBlock.getLoopDepth(); |
| for (int i = toBlockNr - 1; minLoopDepth > 0 && i >= fromBlockNr; i--) { |
| AbstractBlockBase<?> cur = blockAt(i); |
| |
| if (cur.getLoopDepth() < minLoopDepth) { |
| // block with lower loop-depth found . split at the end of this block |
| minLoopDepth = cur.getLoopDepth(); |
| optimalSplitPos = allocator.getLastLirInstructionId(cur) + 2; |
| } |
| } |
| assert optimalSplitPos > allocator.maxOpId() || allocator.isBlockBegin(optimalSplitPos) : "algorithm must move split pos to block boundary"; |
| |
| return optimalSplitPos; |
| } |
| |
| int findOptimalSplitPos(Interval interval, int minSplitPos, int maxSplitPos, boolean doLoopOptimization) { |
| int optimalSplitPos = -1; |
| if (minSplitPos == maxSplitPos) { |
| // trivial case, no optimization of split position possible |
| if (Debug.isLogEnabled()) { |
| Debug.log("min-pos and max-pos are equal, no optimization possible"); |
| } |
| optimalSplitPos = minSplitPos; |
| |
| } else { |
| assert minSplitPos < maxSplitPos : "must be true then"; |
| assert minSplitPos > 0 : "cannot access minSplitPos - 1 otherwise"; |
| |
| // reason for using minSplitPos - 1: when the minimal split pos is exactly at the |
| // beginning of a block, then minSplitPos is also a possible split position. |
| // Use the block before as minBlock, because then minBlock.lastLirInstructionId() + 2 == |
| // minSplitPos |
| AbstractBlockBase<?> minBlock = allocator.blockForId(minSplitPos - 1); |
| |
| // reason for using maxSplitPos - 1: otherwise there would be an assert on failure |
| // when an interval ends at the end of the last block of the method |
| // (in this case, maxSplitPos == allocator().maxLirOpId() + 2, and there is no |
| // block at this opId) |
| AbstractBlockBase<?> maxBlock = allocator.blockForId(maxSplitPos - 1); |
| |
| assert minBlock.getLinearScanNumber() <= maxBlock.getLinearScanNumber() : "invalid order"; |
| if (minBlock == maxBlock) { |
| // split position cannot be moved to block boundary : so split as late as possible |
| if (Debug.isLogEnabled()) { |
| Debug.log("cannot move split pos to block boundary because minPos and maxPos are in same block"); |
| } |
| optimalSplitPos = maxSplitPos; |
| |
| } else { |
| if (interval.hasHoleBetween(maxSplitPos - 1, maxSplitPos) && !allocator.isBlockBegin(maxSplitPos)) { |
| // Do not move split position if the interval has a hole before maxSplitPos. |
| // Intervals resulting from Phi-Functions have more than one definition (marked |
| // as mustHaveRegister) with a hole before each definition. When the register is |
| // needed |
| // for the second definition : an earlier reloading is unnecessary. |
| if (Debug.isLogEnabled()) { |
| Debug.log("interval has hole just before maxSplitPos, so splitting at maxSplitPos"); |
| } |
| optimalSplitPos = maxSplitPos; |
| |
| } else { |
| // seach optimal block boundary between minSplitPos and maxSplitPos |
| if (Debug.isLogEnabled()) { |
| Debug.log("moving split pos to optimal block boundary between block B%d and B%d", minBlock.getId(), maxBlock.getId()); |
| } |
| |
| if (doLoopOptimization) { |
| // Loop optimization: if a loop-end marker is found between min- and |
| // max-position : |
| // then split before this loop |
| int loopEndPos = interval.nextUsageExact(RegisterPriority.LiveAtLoopEnd, allocator.getLastLirInstructionId(minBlock) + 2); |
| if (Debug.isLogEnabled()) { |
| Debug.log("loop optimization: loop end found at pos %d", loopEndPos); |
| } |
| |
| assert loopEndPos > minSplitPos : "invalid order"; |
| if (loopEndPos < maxSplitPos) { |
| // loop-end marker found between min- and max-position |
| // if it is not the end marker for the same loop as the min-position : |
| // then move |
| // the max-position to this loop block. |
| // Desired result: uses tagged as shouldHaveRegister inside a loop cause |
| // a reloading |
| // of the interval (normally, only mustHaveRegister causes a reloading) |
| AbstractBlockBase<?> loopBlock = allocator.blockForId(loopEndPos); |
| |
| if (Debug.isLogEnabled()) { |
| Debug.log("interval is used in loop that ends in block B%d, so trying to move maxBlock back from B%d to B%d", loopBlock.getId(), maxBlock.getId(), loopBlock.getId()); |
| } |
| assert loopBlock != minBlock : "loopBlock and minBlock must be different because block boundary is needed between"; |
| |
| int maxSpillPos = allocator.getLastLirInstructionId(loopBlock) + 2; |
| optimalSplitPos = findOptimalSplitPos(minBlock, loopBlock, maxSpillPos); |
| if (optimalSplitPos == maxSpillPos) { |
| optimalSplitPos = -1; |
| if (Debug.isLogEnabled()) { |
| Debug.log("loop optimization not necessary"); |
| } |
| } else { |
| if (Debug.isLogEnabled()) { |
| Debug.log("loop optimization successful"); |
| } |
| } |
| } |
| } |
| |
| if (optimalSplitPos == -1) { |
| // not calculated by loop optimization |
| optimalSplitPos = findOptimalSplitPos(minBlock, maxBlock, maxSplitPos); |
| } |
| } |
| } |
| } |
| if (Debug.isLogEnabled()) { |
| Debug.log("optimal split position: %d", optimalSplitPos); |
| } |
| |
| return optimalSplitPos; |
| } |
| |
| // split an interval at the optimal position between minSplitPos and |
| // maxSplitPos in two parts: |
| // 1) the left part has already a location assigned |
| // 2) the right part is sorted into to the unhandled-list |
| @SuppressWarnings("try") |
| void splitBeforeUsage(Interval interval, int minSplitPos, int maxSplitPos) { |
| |
| try (Indent indent = Debug.logAndIndent("splitting interval %s between %d and %d", interval, minSplitPos, maxSplitPos)) { |
| |
| assert interval.from() < minSplitPos : "cannot split at start of interval"; |
| assert currentPosition < minSplitPos : "cannot split before current position"; |
| assert minSplitPos <= maxSplitPos : "invalid order"; |
| assert maxSplitPos <= interval.to() : "cannot split after end of interval"; |
| |
| int optimalSplitPos = findOptimalSplitPos(interval, minSplitPos, maxSplitPos, true); |
| |
| assert minSplitPos <= optimalSplitPos && optimalSplitPos <= maxSplitPos : "out of range"; |
| assert optimalSplitPos <= interval.to() : "cannot split after end of interval"; |
| assert optimalSplitPos > interval.from() : "cannot split at start of interval"; |
| |
| if (optimalSplitPos == interval.to() && interval.nextUsage(RegisterPriority.MustHaveRegister, minSplitPos) == Integer.MAX_VALUE) { |
| // the split position would be just before the end of the interval |
| // . no split at all necessary |
| if (Debug.isLogEnabled()) { |
| Debug.log("no split necessary because optimal split position is at end of interval"); |
| } |
| return; |
| } |
| |
| // must calculate this before the actual split is performed and before split position is |
| // moved to odd opId |
| boolean moveNecessary = !allocator.isBlockBegin(optimalSplitPos) && !interval.hasHoleBetween(optimalSplitPos - 1, optimalSplitPos); |
| |
| if (!allocator.isBlockBegin(optimalSplitPos)) { |
| // move position before actual instruction (odd opId) |
| optimalSplitPos = (optimalSplitPos - 1) | 1; |
| } |
| |
| if (Debug.isLogEnabled()) { |
| Debug.log("splitting at position %d", optimalSplitPos); |
| } |
| |
| assert allocator.isBlockBegin(optimalSplitPos) || ((optimalSplitPos & 1) == 1) : "split pos must be odd when not on block boundary"; |
| assert !allocator.isBlockBegin(optimalSplitPos) || ((optimalSplitPos & 1) == 0) : "split pos must be even on block boundary"; |
| |
| Interval splitPart = interval.split(optimalSplitPos, allocator); |
| |
| splitPart.setInsertMoveWhenActivated(moveNecessary); |
| |
| assert splitPart.from() >= currentPosition : "cannot append new interval before current walk position"; |
| unhandledLists.addToListSortedByStartAndUsePositions(RegisterBinding.Any, splitPart); |
| |
| if (Debug.isLogEnabled()) { |
| Debug.log("left interval %s: %s", moveNecessary ? " " : "", interval.logString(allocator)); |
| Debug.log("right interval %s: %s", moveNecessary ? "(move)" : "", splitPart.logString(allocator)); |
| } |
| } |
| } |
| |
| // split an interval at the optimal position between minSplitPos and |
| // maxSplitPos in two parts: |
| // 1) the left part has already a location assigned |
| // 2) the right part is always on the stack and therefore ignored in further processing |
| @SuppressWarnings("try") |
| void splitForSpilling(Interval interval) { |
| // calculate allowed range of splitting position |
| int maxSplitPos = currentPosition; |
| int previousUsage = interval.previousUsage(RegisterPriority.ShouldHaveRegister, maxSplitPos); |
| if (previousUsage == currentPosition) { |
| /* |
| * If there is a usage with ShouldHaveRegister priority at the current position fall |
| * back to MustHaveRegister priority. This only happens if register priority was |
| * downgraded to MustHaveRegister in #allocLockedRegister. |
| */ |
| previousUsage = interval.previousUsage(RegisterPriority.MustHaveRegister, maxSplitPos); |
| } |
| int minSplitPos = Math.max(previousUsage + 1, interval.from()); |
| |
| try (Indent indent = Debug.logAndIndent("splitting and spilling interval %s between %d and %d", interval, minSplitPos, maxSplitPos)) { |
| |
| assert interval.state == State.Active : "why spill interval that is not active?"; |
| assert interval.from() <= minSplitPos : "cannot split before start of interval"; |
| assert minSplitPos <= maxSplitPos : "invalid order"; |
| assert maxSplitPos < interval.to() : "cannot split at end end of interval"; |
| assert currentPosition < interval.to() : "interval must not end before current position"; |
| |
| if (minSplitPos == interval.from()) { |
| // the whole interval is never used, so spill it entirely to memory |
| |
| try (Indent indent2 = Debug.logAndIndent("spilling entire interval because split pos is at beginning of interval (use positions: %d)", interval.usePosList().size())) { |
| |
| assert interval.firstUsage(RegisterPriority.MustHaveRegister) > currentPosition : String.format("interval %s must not have use position before currentPosition %d", interval, |
| currentPosition); |
| |
| allocator.assignSpillSlot(interval); |
| handleSpillSlot(interval); |
| changeSpillState(interval, minSplitPos); |
| |
| // Also kick parent intervals out of register to memory when they have no use |
| // position. This avoids short interval in register surrounded by intervals in |
| // memory . avoid useless moves from memory to register and back |
| Interval parent = interval; |
| while (parent != null && parent.isSplitChild()) { |
| parent = parent.getSplitChildBeforeOpId(parent.from()); |
| |
| if (isRegister(parent.location())) { |
| if (parent.firstUsage(RegisterPriority.ShouldHaveRegister) == Integer.MAX_VALUE) { |
| // parent is never used, so kick it out of its assigned register |
| if (Debug.isLogEnabled()) { |
| Debug.log("kicking out interval %d out of its register because it is never used", parent.operandNumber); |
| } |
| allocator.assignSpillSlot(parent); |
| handleSpillSlot(parent); |
| } else { |
| // do not go further back because the register is actually used by |
| // the interval |
| parent = null; |
| } |
| } |
| } |
| } |
| |
| } else { |
| // search optimal split pos, split interval and spill only the right hand part |
| int optimalSplitPos = findOptimalSplitPos(interval, minSplitPos, maxSplitPos, false); |
| |
| assert minSplitPos <= optimalSplitPos && optimalSplitPos <= maxSplitPos : "out of range"; |
| assert optimalSplitPos < interval.to() : "cannot split at end of interval"; |
| assert optimalSplitPos >= interval.from() : "cannot split before start of interval"; |
| |
| if (!allocator.isBlockBegin(optimalSplitPos)) { |
| // move position before actual instruction (odd opId) |
| optimalSplitPos = (optimalSplitPos - 1) | 1; |
| } |
| |
| try (Indent indent2 = Debug.logAndIndent("splitting at position %d", optimalSplitPos)) { |
| assert allocator.isBlockBegin(optimalSplitPos) || ((optimalSplitPos & 1) == 1) : "split pos must be odd when not on block boundary"; |
| assert !allocator.isBlockBegin(optimalSplitPos) || ((optimalSplitPos & 1) == 0) : "split pos must be even on block boundary"; |
| |
| Interval spilledPart = interval.split(optimalSplitPos, allocator); |
| allocator.assignSpillSlot(spilledPart); |
| handleSpillSlot(spilledPart); |
| changeSpillState(spilledPart, optimalSplitPos); |
| |
| if (!allocator.isBlockBegin(optimalSplitPos)) { |
| if (Debug.isLogEnabled()) { |
| Debug.log("inserting move from interval %d to %d", interval.operandNumber, spilledPart.operandNumber); |
| } |
| insertMove(optimalSplitPos, interval, spilledPart); |
| } |
| |
| // the currentSplitChild is needed later when moves are inserted for reloading |
| assert spilledPart.currentSplitChild() == interval : "overwriting wrong currentSplitChild"; |
| spilledPart.makeCurrentSplitChild(); |
| |
| if (Debug.isLogEnabled()) { |
| Debug.log("left interval: %s", interval.logString(allocator)); |
| Debug.log("spilled interval : %s", spilledPart.logString(allocator)); |
| } |
| } |
| } |
| } |
| } |
| |
| // called during register allocation |
| private void changeSpillState(Interval interval, int spillPos) { |
| switch (interval.spillState()) { |
| case NoSpillStore: { |
| int defLoopDepth = allocator.blockForId(interval.spillDefinitionPos()).getLoopDepth(); |
| int spillLoopDepth = allocator.blockForId(spillPos).getLoopDepth(); |
| |
| if (defLoopDepth < spillLoopDepth) { |
| /* |
| * The loop depth of the spilling position is higher then the loop depth at the |
| * definition of the interval. Move write to memory out of loop. |
| */ |
| if (LinearScan.Options.LIROptLSRAOptimizeSpillPosition.getValue()) { |
| // find best spill position in dominator the tree |
| interval.setSpillState(SpillState.SpillInDominator); |
| } else { |
| // store at definition of the interval |
| interval.setSpillState(SpillState.StoreAtDefinition); |
| } |
| } else { |
| /* |
| * The interval is currently spilled only once, so for now there is no reason to |
| * store the interval at the definition. |
| */ |
| interval.setSpillState(SpillState.OneSpillStore); |
| } |
| break; |
| } |
| |
| case OneSpillStore: { |
| if (LinearScan.Options.LIROptLSRAOptimizeSpillPosition.getValue()) { |
| // the interval is spilled more then once |
| interval.setSpillState(SpillState.SpillInDominator); |
| } else { |
| // It is better to store it to memory at the definition. |
| interval.setSpillState(SpillState.StoreAtDefinition); |
| } |
| break; |
| } |
| |
| case SpillInDominator: |
| case StoreAtDefinition: |
| case StartInMemory: |
| case NoOptimization: |
| case NoDefinitionFound: |
| // nothing to do |
| break; |
| |
| default: |
| throw GraalError.shouldNotReachHere("other states not allowed at this time"); |
| } |
| } |
| |
| /** |
| * This is called for every interval that is assigned to a stack slot. |
| */ |
| protected void handleSpillSlot(Interval interval) { |
| assert interval.location() != null && (interval.canMaterialize() || isStackSlotValue(interval.location())) : "interval not assigned to a stack slot " + interval; |
| // Do nothing. Stack slots are not processed in this implementation. |
| } |
| |
| void splitStackInterval(Interval interval) { |
| int minSplitPos = currentPosition + 1; |
| int maxSplitPos = Math.min(interval.firstUsage(RegisterPriority.ShouldHaveRegister), interval.to()); |
| |
| splitBeforeUsage(interval, minSplitPos, maxSplitPos); |
| } |
| |
| void splitWhenPartialRegisterAvailable(Interval interval, int registerAvailableUntil) { |
| int minSplitPos = Math.max(interval.previousUsage(RegisterPriority.ShouldHaveRegister, registerAvailableUntil), interval.from() + 1); |
| splitBeforeUsage(interval, minSplitPos, registerAvailableUntil); |
| } |
| |
| void splitAndSpillInterval(Interval interval) { |
| assert interval.state == State.Active || interval.state == State.Inactive : "other states not allowed"; |
| |
| int currentPos = currentPosition; |
| if (interval.state == State.Inactive) { |
| // the interval is currently inactive, so no spill slot is needed for now. |
| // when the split part is activated, the interval has a new chance to get a register, |
| // so in the best case no stack slot is necessary |
| assert interval.hasHoleBetween(currentPos - 1, currentPos + 1) : "interval can not be inactive otherwise"; |
| splitBeforeUsage(interval, currentPos + 1, currentPos + 1); |
| |
| } else { |
| // search the position where the interval must have a register and split |
| // at the optimal position before. |
| // The new created part is added to the unhandled list and will get a register |
| // when it is activated |
| int minSplitPos = currentPos + 1; |
| int maxSplitPos = Math.min(interval.nextUsage(RegisterPriority.MustHaveRegister, minSplitPos), interval.to()); |
| |
| splitBeforeUsage(interval, minSplitPos, maxSplitPos); |
| |
| assert interval.nextUsage(RegisterPriority.MustHaveRegister, currentPos) == Integer.MAX_VALUE : "the remaining part is spilled to stack and therefore has no register"; |
| splitForSpilling(interval); |
| } |
| } |
| |
| @SuppressWarnings("try") |
| boolean allocFreeRegister(Interval interval) { |
| try (Indent indent = Debug.logAndIndent("trying to find free register for %s", interval)) { |
| |
| initUseLists(true); |
| freeExcludeActiveFixed(); |
| freeExcludeActiveAny(); |
| freeCollectInactiveFixed(interval); |
| freeCollectInactiveAny(interval); |
| // freeCollectUnhandled(fixedKind, cur); |
| assert unhandledLists.get(RegisterBinding.Fixed) == Interval.EndMarker : "must not have unhandled fixed intervals because all fixed intervals have a use at position 0"; |
| |
| // usePos contains the start of the next interval that has this register assigned |
| // (either as a fixed register or a normal allocated register in the past) |
| // only intervals overlapping with cur are processed, non-overlapping invervals can be |
| // ignored safely |
| if (Debug.isLogEnabled()) { |
| // Enable this logging to see all register states |
| try (Indent indent2 = Debug.logAndIndent("state of registers:")) { |
| for (Register register : availableRegs) { |
| int i = register.number; |
| Debug.log("reg %d: usePos: %d", register.number, usePos[i]); |
| } |
| } |
| } |
| |
| Register hint = null; |
| Interval locationHint = interval.locationHint(true); |
| if (locationHint != null && locationHint.location() != null && isRegister(locationHint.location())) { |
| hint = asRegister(locationHint.location()); |
| if (Debug.isLogEnabled()) { |
| Debug.log("hint register %d from interval %s", hint.number, locationHint); |
| } |
| } |
| assert interval.location() == null : "register already assigned to interval"; |
| |
| // the register must be free at least until this position |
| int regNeededUntil = interval.from() + 1; |
| int intervalTo = interval.to(); |
| |
| boolean needSplit = false; |
| int splitPos = -1; |
| |
| Register reg = null; |
| Register minFullReg = null; |
| Register maxPartialReg = null; |
| |
| for (Register availableReg : availableRegs) { |
| int number = availableReg.number; |
| if (usePos[number] >= intervalTo) { |
| // this register is free for the full interval |
| if (minFullReg == null || availableReg.equals(hint) || (usePos[number] < usePos[minFullReg.number] && !minFullReg.equals(hint))) { |
| minFullReg = availableReg; |
| } |
| } else if (usePos[number] > regNeededUntil) { |
| // this register is at least free until regNeededUntil |
| if (maxPartialReg == null || availableReg.equals(hint) || (usePos[number] > usePos[maxPartialReg.number] && !maxPartialReg.equals(hint))) { |
| maxPartialReg = availableReg; |
| } |
| } |
| } |
| |
| if (minFullReg != null) { |
| reg = minFullReg; |
| } else if (maxPartialReg != null) { |
| needSplit = true; |
| reg = maxPartialReg; |
| } else { |
| return false; |
| } |
| |
| splitPos = usePos[reg.number]; |
| interval.assignLocation(reg.asValue(interval.kind())); |
| if (Debug.isLogEnabled()) { |
| Debug.log("selected register %d", reg.number); |
| } |
| |
| assert splitPos > 0 : "invalid splitPos"; |
| if (needSplit) { |
| // register not available for full interval, so split it |
| splitWhenPartialRegisterAvailable(interval, splitPos); |
| } |
| // only return true if interval is completely assigned |
| return true; |
| } |
| } |
| |
| void splitAndSpillIntersectingIntervals(Register reg) { |
| assert reg != null : "no register assigned"; |
| |
| for (int i = 0; i < spillIntervals[reg.number].size(); i++) { |
| Interval interval = spillIntervals[reg.number].get(i); |
| removeFromList(interval); |
| splitAndSpillInterval(interval); |
| } |
| } |
| |
| // Split an Interval and spill it to memory so that cur can be placed in a register |
| @SuppressWarnings("try") |
| void allocLockedRegister(Interval interval) { |
| try (Indent indent = Debug.logAndIndent("alloc locked register: need to split and spill to get register for %s", interval)) { |
| |
| // the register must be free at least until this position |
| int firstUsage = interval.firstUsage(RegisterPriority.MustHaveRegister); |
| int firstShouldHaveUsage = interval.firstUsage(RegisterPriority.ShouldHaveRegister); |
| int regNeededUntil = Math.min(firstUsage, interval.from() + 1); |
| int intervalTo = interval.to(); |
| assert regNeededUntil >= 0 && regNeededUntil < Integer.MAX_VALUE : "interval has no use"; |
| |
| Register reg; |
| Register ignore; |
| /* |
| * In the common case we don't spill registers that have _any_ use position that is |
| * closer than the next use of the current interval, but if we can't spill the current |
| * interval we weaken this strategy and also allow spilling of intervals that have a |
| * non-mandatory requirements (no MustHaveRegister use position). |
| */ |
| for (RegisterPriority registerPriority = RegisterPriority.LiveAtLoopEnd; true; registerPriority = RegisterPriority.MustHaveRegister) { |
| // collect current usage of registers |
| initUseLists(false); |
| spillExcludeActiveFixed(); |
| // spillBlockUnhandledFixed(cur); |
| assert unhandledLists.get(RegisterBinding.Fixed) == Interval.EndMarker : "must not have unhandled fixed intervals because all fixed intervals have a use at position 0"; |
| spillBlockInactiveFixed(interval); |
| spillCollectActiveAny(registerPriority); |
| spillCollectInactiveAny(interval); |
| if (Debug.isLogEnabled()) { |
| printRegisterState(); |
| } |
| |
| reg = null; |
| ignore = interval.location() != null && isRegister(interval.location()) ? asRegister(interval.location()) : null; |
| |
| for (Register availableReg : availableRegs) { |
| int number = availableReg.number; |
| if (availableReg.equals(ignore)) { |
| // this register must be ignored |
| } else if (usePos[number] > regNeededUntil) { |
| if (reg == null || (usePos[number] > usePos[reg.number])) { |
| reg = availableReg; |
| } |
| } |
| } |
| |
| int regUsePos = (reg == null ? 0 : usePos[reg.number]); |
| if (regUsePos <= firstShouldHaveUsage) { |
| if (Debug.isLogEnabled()) { |
| Debug.log("able to spill current interval. firstUsage(register): %d, usePos: %d", firstUsage, regUsePos); |
| } |
| |
| if (firstUsage <= interval.from() + 1) { |
| if (registerPriority.equals(RegisterPriority.LiveAtLoopEnd)) { |
| /* |
| * Tool of last resort: we can not spill the current interval so we try |
| * to spill an active interval that has a usage but do not require a |
| * register. |
| */ |
| Debug.log("retry with register priority must have register"); |
| continue; |
| } |
| String description = generateOutOfRegErrorMsg(interval, firstUsage, availableRegs); |
| /* |
| * assign a reasonable register and do a bailout in product mode to avoid |
| * errors |
| */ |
| allocator.assignSpillSlot(interval); |
| Debug.dump(Debug.INFO_LOG_LEVEL, allocator.getLIR(), description); |
| allocator.printIntervals(description); |
| throw new OutOfRegistersException("LinearScan: no register found", description); |
| } |
| |
| splitAndSpillInterval(interval); |
| return; |
| } |
| break; |
| } |
| |
| boolean needSplit = blockPos[reg.number] <= intervalTo; |
| |
| int splitPos = blockPos[reg.number]; |
| |
| if (Debug.isLogEnabled()) { |
| Debug.log("decided to use register %d", reg.number); |
| } |
| assert splitPos > 0 : "invalid splitPos"; |
| assert needSplit || splitPos > interval.from() : "splitting interval at from"; |
| |
| interval.assignLocation(reg.asValue(interval.kind())); |
| if (needSplit) { |
| // register not available for full interval : so split it |
| splitWhenPartialRegisterAvailable(interval, splitPos); |
| } |
| |
| // perform splitting and spilling for all affected intervals |
| splitAndSpillIntersectingIntervals(reg); |
| return; |
| } |
| } |
| |
| private static String generateOutOfRegErrorMsg(Interval interval, int firstUsage, Register[] availableRegs) { |
| return "Cannot spill interval (" + interval + ") that is used in first instruction (possible reason: no register found) firstUsage=" + firstUsage + |
| ", interval.from()=" + interval.from() + "; already used candidates: " + Arrays.toString(availableRegs); |
| } |
| |
| @SuppressWarnings("try") |
| void printRegisterState() { |
| try (Indent indent2 = Debug.logAndIndent("state of registers:")) { |
| for (Register reg : availableRegs) { |
| int i = reg.number; |
| try (Indent indent3 = Debug.logAndIndent("reg %d: usePos: %d, blockPos: %d, intervals: ", i, usePos[i], blockPos[i])) { |
| for (int j = 0; j < spillIntervals[i].size(); j++) { |
| Debug.log("%s ", spillIntervals[i].get(j)); |
| } |
| } |
| } |
| } |
| } |
| |
| boolean noAllocationPossible(Interval interval) { |
| if (allocator.callKillsRegisters()) { |
| // fast calculation of intervals that can never get a register because the |
| // the next instruction is a call that blocks all registers |
| // Note: this only works if a call kills all registers |
| |
| // check if this interval is the result of a split operation |
| // (an interval got a register until this position) |
| int pos = interval.from(); |
| if (isOdd(pos)) { |
| // the current instruction is a call that blocks all registers |
| if (pos < allocator.maxOpId() && allocator.hasCall(pos + 1) && interval.to() > pos + 1) { |
| if (Debug.isLogEnabled()) { |
| Debug.log("free register cannot be available because all registers blocked by following call"); |
| } |
| |
| // safety check that there is really no register available |
| assert !allocFreeRegister(interval) : "found a register for this interval"; |
| return true; |
| } |
| } |
| } |
| return false; |
| } |
| |
| void initVarsForAlloc(Interval interval) { |
| AllocatableRegisters allocatableRegisters = allocator.getRegisterAllocationConfig().getAllocatableRegisters(interval.kind().getPlatformKind()); |
| availableRegs = allocatableRegisters.allocatableRegisters; |
| minReg = allocatableRegisters.minRegisterNumber; |
| maxReg = allocatableRegisters.maxRegisterNumber; |
| } |
| |
| static boolean isMove(LIRInstruction op, Interval from, Interval to) { |
| if (op instanceof ValueMoveOp) { |
| ValueMoveOp move = (ValueMoveOp) op; |
| if (isVariable(move.getInput()) && isVariable(move.getResult())) { |
| return move.getInput() != null && move.getInput().equals(from.operand) && move.getResult() != null && move.getResult().equals(to.operand); |
| } |
| } |
| return false; |
| } |
| |
| // optimization (especially for phi functions of nested loops): |
| // assign same spill slot to non-intersecting intervals |
| void combineSpilledIntervals(Interval interval) { |
| if (interval.isSplitChild()) { |
| // optimization is only suitable for split parents |
| return; |
| } |
| |
| Interval registerHint = interval.locationHint(false); |
| if (registerHint == null) { |
| // cur is not the target of a move : otherwise registerHint would be set |
| return; |
| } |
| assert registerHint.isSplitParent() : "register hint must be split parent"; |
| |
| if (interval.spillState() != SpillState.NoOptimization || registerHint.spillState() != SpillState.NoOptimization) { |
| // combining the stack slots for intervals where spill move optimization is applied |
| // is not benefitial and would cause problems |
| return; |
| } |
| |
| int beginPos = interval.from(); |
| int endPos = interval.to(); |
| if (endPos > allocator.maxOpId() || isOdd(beginPos) || isOdd(endPos)) { |
| // safety check that lirOpWithId is allowed |
| return; |
| } |
| |
| if (!isMove(allocator.instructionForId(beginPos), registerHint, interval) || !isMove(allocator.instructionForId(endPos), interval, registerHint)) { |
| // cur and registerHint are not connected with two moves |
| return; |
| } |
| |
| Interval beginHint = registerHint.getSplitChildAtOpId(beginPos, LIRInstruction.OperandMode.USE, allocator); |
| Interval endHint = registerHint.getSplitChildAtOpId(endPos, LIRInstruction.OperandMode.DEF, allocator); |
| if (beginHint == endHint || beginHint.to() != beginPos || endHint.from() != endPos) { |
| // registerHint must be split : otherwise the re-writing of use positions does not work |
| return; |
| } |
| |
| assert beginHint.location() != null : "must have register assigned"; |
| assert endHint.location() == null : "must not have register assigned"; |
| assert interval.firstUsage(RegisterPriority.MustHaveRegister) == beginPos : "must have use position at begin of interval because of move"; |
| assert endHint.firstUsage(RegisterPriority.MustHaveRegister) == endPos : "must have use position at begin of interval because of move"; |
| |
| if (isRegister(beginHint.location())) { |
| // registerHint is not spilled at beginPos : so it would not be benefitial to |
| // immediately spill cur |
| return; |
| } |
| assert registerHint.spillSlot() != null : "must be set when part of interval was spilled"; |
| |
| // modify intervals such that cur gets the same stack slot as registerHint |
| // delete use positions to prevent the intervals to get a register at beginning |
| interval.setSpillSlot(registerHint.spillSlot()); |
| interval.removeFirstUsePos(); |
| endHint.removeFirstUsePos(); |
| } |
| |
| // allocate a physical register or memory location to an interval |
| @Override |
| @SuppressWarnings("try") |
| protected boolean activateCurrent(Interval interval) { |
| boolean result = true; |
| |
| try (Indent indent = Debug.logAndIndent("activating interval %s, splitParent: %d", interval, interval.splitParent().operandNumber)) { |
| |
| final Value operand = interval.operand; |
| if (interval.location() != null && isStackSlotValue(interval.location())) { |
| // activating an interval that has a stack slot assigned . split it at first use |
| // position |
| // used for method parameters |
| if (Debug.isLogEnabled()) { |
| Debug.log("interval has spill slot assigned (method parameter) . split it before first use"); |
| } |
| splitStackInterval(interval); |
| result = false; |
| |
| } else { |
| if (interval.location() == null) { |
| // interval has not assigned register . normal allocation |
| // (this is the normal case for most intervals) |
| if (Debug.isLogEnabled()) { |
| Debug.log("normal allocation of register"); |
| } |
| |
| // assign same spill slot to non-intersecting intervals |
| combineSpilledIntervals(interval); |
| |
| initVarsForAlloc(interval); |
| if (noAllocationPossible(interval) || !allocFreeRegister(interval)) { |
| // no empty register available. |
| // split and spill another interval so that this interval gets a register |
| allocLockedRegister(interval); |
| } |
| |
| // spilled intervals need not be move to active-list |
| if (!isRegister(interval.location())) { |
| result = false; |
| } |
| } |
| } |
| |
| // load spilled values that become active from stack slot to register |
| if (interval.insertMoveWhenActivated()) { |
| assert interval.isSplitChild(); |
| assert interval.currentSplitChild() != null; |
| assert !interval.currentSplitChild().operand.equals(operand) : "cannot insert move between same interval"; |
| if (Debug.isLogEnabled()) { |
| Debug.log("Inserting move from interval %d to %d because insertMoveWhenActivated is set", interval.currentSplitChild().operandNumber, interval.operandNumber); |
| } |
| |
| insertMove(interval.from(), interval.currentSplitChild(), interval); |
| } |
| interval.makeCurrentSplitChild(); |
| |
| } |
| |
| return result; // true = interval is moved to active list |
| } |
| |
| public void finishAllocation() { |
| // must be called when all intervals are allocated |
| moveResolver.resolveAndAppendMoves(); |
| } |
| } |
