hotspot/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.lir/src/org/graalvm/compiler/lir/alloc/trace/TraceGlobalMoveResolver.java - platform/libcore - Git at Google

 /*
  * 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.trace;

 import static org.graalvm.compiler.lir.LIRValueUtil.asVirtualStackSlot;
 import static org.graalvm.compiler.lir.LIRValueUtil.isStackSlotValue;
 import static org.graalvm.compiler.lir.LIRValueUtil.isVirtualStackSlot;
 import static org.graalvm.compiler.lir.alloc.trace.TraceUtil.asShadowedRegisterValue;
 import static org.graalvm.compiler.lir.alloc.trace.TraceUtil.isShadowedRegisterValue;
 import static jdk.vm.ci.code.ValueUtil.asAllocatableValue;
 import static jdk.vm.ci.code.ValueUtil.asRegister;
 import static jdk.vm.ci.code.ValueUtil.asStackSlot;
 import static jdk.vm.ci.code.ValueUtil.isIllegal;
 import static jdk.vm.ci.code.ValueUtil.isRegister;
 import static jdk.vm.ci.code.ValueUtil.isStackSlot;

 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.List;

 import org.graalvm.compiler.core.common.LIRKind;
 import org.graalvm.compiler.debug.Debug;
 import org.graalvm.compiler.debug.DebugCounter;
 import org.graalvm.compiler.debug.GraalError;
 import org.graalvm.compiler.debug.Indent;
 import org.graalvm.compiler.lir.LIRInsertionBuffer;
 import org.graalvm.compiler.lir.LIRInstruction;
 import org.graalvm.compiler.lir.VirtualStackSlot;
 import org.graalvm.compiler.lir.framemap.FrameMap;
 import org.graalvm.compiler.lir.framemap.FrameMapBuilder;
 import org.graalvm.compiler.lir.framemap.FrameMapBuilderTool;
 import org.graalvm.compiler.lir.gen.LIRGenerationResult;
 import org.graalvm.compiler.lir.gen.LIRGeneratorTool.MoveFactory;

 import jdk.vm.ci.code.Architecture;
 import jdk.vm.ci.code.RegisterArray;
 import jdk.vm.ci.code.StackSlot;
 import jdk.vm.ci.meta.AllocatableValue;
 import jdk.vm.ci.meta.Value;

 /**
  */
 public final class TraceGlobalMoveResolver extends TraceGlobalMoveResolutionPhase.MoveResolver {

     private static final DebugCounter cycleBreakingSlotsAllocated = Debug.counter("TraceRA[cycleBreakingSlotsAllocated(global)]");
     private static final DebugCounter cycleBreakingSlotsReused = Debug.counter("TraceRA[cycleBreakingSlotsReused(global)]");

     private int insertIdx;
     private LIRInsertionBuffer insertionBuffer; // buffer where moves are inserted

     private final List<Value> mappingFrom;
     private final List<Value> mappingFromStack;
     private final List<AllocatableValue> mappingTo;
     private final int[] registerBlocked;
     private static final int STACK_SLOT_IN_CALLER_FRAME_IDX = -1;
     private int[] stackBlocked;
     private final int firstVirtualStackIndex;
     private final MoveFactory spillMoveFactory;
     private final FrameMapBuilder frameMapBuilder;

     private void setValueBlocked(Value location, int direction) {
         assert direction == 1 || direction == -1 : "out of bounds";
         if (isStackSlotValue(location)) {
             int stackIdx = getStackArrayIndex(location);
             if (stackIdx == STACK_SLOT_IN_CALLER_FRAME_IDX) {
                 // incoming stack arguments can be ignored
                 return;
             }
             if (stackIdx >= stackBlocked.length) {
                 stackBlocked = Arrays.copyOf(stackBlocked, stackIdx + 1);
             }
             stackBlocked[stackIdx] += direction;
         } else {
             assert direction == 1 || direction == -1 : "out of bounds";
             if (isRegister(location)) {
                 registerBlocked[asRegister(location).number] += direction;
             } else {
                 throw GraalError.shouldNotReachHere("unhandled value " + location);
             }
         }
     }

     private int valueBlocked(Value location) {
         if (isStackSlotValue(location)) {
             int stackIdx = getStackArrayIndex(location);
             if (stackIdx == STACK_SLOT_IN_CALLER_FRAME_IDX) {
                 // incoming stack arguments are always blocked (aka they can not be written)
                 return 1;
             }
             if (stackIdx >= stackBlocked.length) {
                 return 0;
             }
             return stackBlocked[stackIdx];
         }
         if (isRegister(location)) {
             return registerBlocked[asRegister(location).number];
         }
         throw GraalError.shouldNotReachHere("unhandled value " + location);
     }

     private static boolean areMultipleReadsAllowed() {
         return true;
     }

     private boolean hasMappings() {
         return mappingFrom.size() > 0;
     }

     private MoveFactory getSpillMoveFactory() {
         return spillMoveFactory;
     }

     private RegisterArray getRegisters() {
         return frameMapBuilder.getRegisterConfig().getAllocatableRegisters();
     }

     public TraceGlobalMoveResolver(LIRGenerationResult res, MoveFactory spillMoveFactory, Architecture arch) {

         this.mappingFrom = new ArrayList<>(8);
         this.mappingFromStack = new ArrayList<>(8);
         this.mappingTo = new ArrayList<>(8);
         this.insertIdx = -1;
         this.insertionBuffer = new LIRInsertionBuffer();

         this.frameMapBuilder = res.getFrameMapBuilder();
         this.spillMoveFactory = spillMoveFactory;
         this.registerBlocked = new int[arch.getRegisters().size()];

         FrameMapBuilderTool frameMapBuilderTool = (FrameMapBuilderTool) frameMapBuilder;
         this.stackBlocked = new int[frameMapBuilderTool.getNumberOfStackSlots()];

         FrameMap frameMap = frameMapBuilderTool.getFrameMap();
         this.firstVirtualStackIndex = !frameMap.frameNeedsAllocating() ? 0 : frameMap.currentFrameSize() + 1;
     }

     private boolean checkEmpty() {
         for (int i = 0; i < stackBlocked.length; i++) {
             assert stackBlocked[i] == 0 : "stack map must be empty before and after processing";
         }
         assert mappingFrom.size() == 0 && mappingTo.size() == 0 && mappingFromStack.size() == 0 : "list must be empty before and after processing";
         for (int i = 0; i < getRegisters().size(); i++) {
             assert registerBlocked[i] == 0 : "register map must be empty before and after processing";
         }
         return true;
     }

     private boolean verifyBeforeResolve() {
         assert mappingFrom.size() == mappingTo.size() && mappingFrom.size() == mappingFromStack.size() : "length must be equal";
         assert insertIdx != -1 : "insert position not set";

         int i;
         int j;
         if (!areMultipleReadsAllowed()) {
             for (i = 0; i < mappingFrom.size(); i++) {
                 for (j = i + 1; j < mappingFrom.size(); j++) {
                     assert mappingFrom.get(i) == null || mappingFrom.get(i) != mappingFrom.get(j) : "cannot read from same interval twice";
                 }
             }
         }

         for (i = 0; i < mappingTo.size(); i++) {
             for (j = i + 1; j < mappingTo.size(); j++) {
                 assert mappingTo.get(i) != mappingTo.get(j) : "cannot write to same interval twice";
             }
         }

         for (i = 0; i < mappingTo.size(); i++) {
             Value to = mappingTo.get(i);
             assert !isStackSlotValue(to) || getStackArrayIndex(to) != STACK_SLOT_IN_CALLER_FRAME_IDX : "Cannot move to in argument: " + to;
         }

         HashSet<Value> usedRegs = new HashSet<>();
         if (!areMultipleReadsAllowed()) {
             for (i = 0; i < mappingFrom.size(); i++) {
                 Value from = mappingFrom.get(i);
                 if (from != null && !isIllegal(from)) {
                     boolean unique = usedRegs.add(from);
                     assert unique : "cannot read from same register twice";
                 }
             }
         }

         usedRegs.clear();
         for (i = 0; i < mappingTo.size(); i++) {
             Value to = mappingTo.get(i);
             if (isIllegal(to)) {
                 // After insertion the location may become illegal, so don't check it since multiple
                 // intervals might be illegal.
                 continue;
             }
             boolean unique = usedRegs.add(to);
             assert unique : "cannot write to same register twice";
         }

         return true;
     }

     // mark assignedReg and assignedRegHi of the interval as blocked
     private void block(Value location) {
         if (mightBeBlocked(location)) {
             assert areMultipleReadsAllowed() || valueBlocked(location) == 0 : "location already marked as used: " + location;
             setValueBlocked(location, 1);
             Debug.log("block %s", location);
         }
     }

     // mark assignedReg and assignedRegHi of the interval as unblocked
     private void unblock(Value location) {
         if (mightBeBlocked(location)) {
             assert valueBlocked(location) > 0 : "location already marked as unused: " + location;
             setValueBlocked(location, -1);
             Debug.log("unblock %s", location);
         }
     }

     /**
      * Checks if {@code to} is not blocked or is only blocked by {@code from}.
      */
     private boolean safeToProcessMove(Value fromLocation, Value toLocation) {
         if (mightBeBlocked(toLocation)) {
             if ((valueBlocked(toLocation) > 1 || (valueBlocked(toLocation) == 1 && !isMoveToSelf(fromLocation, toLocation)))) {
                 return false;
             }
         }

         return true;
     }

     public static boolean isMoveToSelf(Value from, Value to) {
         assert to != null;
         if (to.equals(from)) {
             return true;
         }
         if (from == null) {
             return false;
         }
         if (isShadowedRegisterValue(from)) {
             /* From is a shadowed register. */
             if (isShadowedRegisterValue(to)) {
                 // both shadowed but not equal
                 return false;
             }
             ShadowedRegisterValue shadowed = asShadowedRegisterValue(from);
             if (isRegisterToRegisterMoveToSelf(shadowed.getRegister(), to)) {
                 return true;
             }
             if (isStackSlotValue(to)) {
                 return to.equals(shadowed.getStackSlot());
             }
         } else {
             /*
              * A shadowed destination value is never a self move it both values are not equal. Fall
              * through.
              */
             // if (isShadowedRegisterValue(to)) return false;

             return isRegisterToRegisterMoveToSelf(from, to);
         }
         return false;
     }

     private static boolean isRegisterToRegisterMoveToSelf(Value from, Value to) {
         if (to.equals(from)) {
             return true;
         }
         if (isRegister(from) && isRegister(to) && asRegister(from).equals(asRegister(to))) {
             // Values differ but Registers are the same
             assert LIRKind.verifyMoveKinds(to.getValueKind(), from.getValueKind()) : String.format("Same register but Kind mismatch %s <- %s", to, from);
             return true;
         }
         return false;
     }

     private static boolean mightBeBlocked(Value location) {
         return isRegister(location) || isStackSlotValue(location);
     }

     private void createInsertionBuffer(List<LIRInstruction> list) {
         assert !insertionBuffer.initialized() : "overwriting existing buffer";
         insertionBuffer.init(list);
     }

     private void appendInsertionBuffer() {
         if (insertionBuffer.initialized()) {
             insertionBuffer.finish();
         }
         assert !insertionBuffer.initialized() : "must be uninitialized now";

         insertIdx = -1;
     }

     private void insertMove(Value fromOperand, AllocatableValue toOperand) {
         assert !fromOperand.equals(toOperand) : "from and to are equal: " + fromOperand + " vs. " + toOperand;
         assert LIRKind.verifyMoveKinds(fromOperand.getValueKind(), fromOperand.getValueKind()) : "move between different types";
         assert insertIdx != -1 : "must setup insert position first";

         insertionBuffer.append(insertIdx, createMove(fromOperand, toOperand));

         if (Debug.isLogEnabled()) {
             Debug.log("insert move from %s to %s at %d", fromOperand, toOperand, insertIdx);
         }
     }

     /**
      * @param fromOpr Operand of the {@code from} interval
      * @param toOpr Operand of the {@code to} interval
      */
     private LIRInstruction createMove(Value fromOpr, AllocatableValue toOpr) {
         if (isStackSlotValue(toOpr) && isStackSlotValue(fromOpr)) {
             return getSpillMoveFactory().createStackMove(toOpr, asAllocatableValue(fromOpr));
         }
         return getSpillMoveFactory().createMove(toOpr, fromOpr);
     }

     @SuppressWarnings("try")
     private void resolveMappings() {
         try (Indent indent = Debug.logAndIndent("resolveMapping")) {
             assert verifyBeforeResolve();
             if (Debug.isLogEnabled()) {
                 printMapping();
             }

             // Block all registers that are used as input operands of a move.
             // When a register is blocked, no move to this register is emitted.
             // This is necessary for detecting cycles in moves.
             for (int i = mappingFrom.size() - 1; i >= 0; i--) {
                 Value from = mappingFrom.get(i);
                 block(from);
             }

             ArrayList<AllocatableValue> busySpillSlots = null;
             while (mappingFrom.size() > 0) {
                 boolean processedInterval = false;

                 int spillCandidate = -1;
                 for (int i = mappingFrom.size() - 1; i >= 0; i--) {
                     Value fromLocation = mappingFrom.get(i);
                     AllocatableValue toLocation = mappingTo.get(i);
                     if (safeToProcessMove(fromLocation, toLocation)) {
                         // this interval can be processed because target is free
                         insertMove(fromLocation, toLocation);
                         unblock(fromLocation);
                         if (isStackSlotValue(toLocation)) {
                             if (busySpillSlots == null) {
                                 busySpillSlots = new ArrayList<>(2);
                             }
                             busySpillSlots.add(toLocation);
                         }
                         mappingFrom.remove(i);
                         mappingFromStack.remove(i);
                         mappingTo.remove(i);

                         processedInterval = true;
                     } else if (fromLocation != null) {
                         if (isRegister(fromLocation) && (busySpillSlots == null || !busySpillSlots.contains(mappingFromStack.get(i)))) {
                             // this interval cannot be processed now because target is not free
                             // it starts in a register, so it is a possible candidate for spilling
                             spillCandidate = i;
                         } else if (isStackSlotValue(fromLocation) && spillCandidate == -1) {
                             // fall back to spill a stack slot in case no other candidate is found
                             spillCandidate = i;
                         }
                     }
                 }

                 if (!processedInterval) {
                     breakCycle(spillCandidate);
                 }
             }
         }

         // check that all intervals have been processed
         assert checkEmpty();
     }

     @SuppressWarnings("try")
     private void breakCycle(int spillCandidate) {
         // no move could be processed because there is a cycle in the move list
         // (e.g. r1 . r2, r2 . r1), so one interval must be spilled to memory
         assert spillCandidate != -1 : "no interval in register for spilling found";

         // create a new spill interval and assign a stack slot to it
         Value from = mappingFrom.get(spillCandidate);
         try (Indent indent = Debug.logAndIndent("BreakCycle: %s", from)) {
             AllocatableValue spillSlot = null;
             if (TraceRegisterAllocationPhase.Options.TraceRAreuseStackSlotsForMoveResolutionCycleBreaking.getValue() && !isStackSlotValue(from)) {
                 // don't use the stack slot if from is already the stack slot
                 Value fromStack = mappingFromStack.get(spillCandidate);
                 if (fromStack != null) {
                     spillSlot = (AllocatableValue) fromStack;
                     cycleBreakingSlotsReused.increment();
                     Debug.log("reuse slot for spilling: %s", spillSlot);
                 }
             }
             if (spillSlot == null) {
                 spillSlot = frameMapBuilder.allocateSpillSlot(from.getValueKind());
                 cycleBreakingSlotsAllocated.increment();
                 Debug.log("created new slot for spilling: %s", spillSlot);
                 // insert a move from register to stack and update the mapping
                 insertMove(from, spillSlot);
             }
             block(spillSlot);
             mappingFrom.set(spillCandidate, spillSlot);
             unblock(from);
         }
     }

     @SuppressWarnings("try")
     private void printMapping() {
         try (Indent indent = Debug.logAndIndent("Mapping")) {
             for (int i = mappingFrom.size() - 1; i >= 0; i--) {
                 Debug.log("move %s <- %s (%s)", mappingTo.get(i), mappingFrom.get(i), mappingFromStack.get(i));
             }
         }
     }

     public void setInsertPosition(List<LIRInstruction> insertList, int insertIdx) {
         assert this.insertIdx == -1 : "use moveInsertPosition instead of setInsertPosition when data already set";

         createInsertionBuffer(insertList);
         this.insertIdx = insertIdx;
     }

     @Override
     public void addMapping(Value from, AllocatableValue to, Value fromStack) {
         if (Debug.isLogEnabled()) {
             Debug.log("add move mapping from %s to %s", from, to);
         }

         assert !from.equals(to) : "from and to interval equal: " + from;
         assert LIRKind.verifyMoveKinds(to.getValueKind(), from.getValueKind()) : String.format("Kind mismatch: %s vs. %s, from=%s, to=%s", from.getValueKind(), to.getValueKind(), from, to);
         assert fromStack == null || LIRKind.verifyMoveKinds(to.getValueKind(), fromStack.getValueKind()) : String.format("Kind mismatch: %s vs. %s, fromStack=%s, to=%s", fromStack.getValueKind(),
                         to.getValueKind(), fromStack, to);
         mappingFrom.add(from);
         mappingFromStack.add(fromStack);
         mappingTo.add(to);
     }

     public void resolveAndAppendMoves() {
         if (hasMappings()) {
             resolveMappings();
         }
         appendInsertionBuffer();
     }

     private int getStackArrayIndex(Value stackSlotValue) {
         if (isStackSlot(stackSlotValue)) {
             return getStackArrayIndex(asStackSlot(stackSlotValue));
         }
         if (isVirtualStackSlot(stackSlotValue)) {
             return getStackArrayIndex(asVirtualStackSlot(stackSlotValue));
         }
         throw GraalError.shouldNotReachHere("value is not a stack slot: " + stackSlotValue);
     }

     private int getStackArrayIndex(StackSlot stackSlot) {
         int stackIdx;
         if (stackSlot.isInCallerFrame()) {
             // incoming stack arguments can be ignored
             stackIdx = STACK_SLOT_IN_CALLER_FRAME_IDX;
         } else {
             assert stackSlot.getRawAddFrameSize() : "Unexpected stack slot: " + stackSlot;
             int offset = -stackSlot.getRawOffset();
             assert 0 <= offset && offset < firstVirtualStackIndex : String.format("Wrong stack slot offset: %d (first virtual stack slot index: %d", offset, firstVirtualStackIndex);
             stackIdx = offset;
         }
         return stackIdx;
     }

     private int getStackArrayIndex(VirtualStackSlot virtualStackSlot) {
         return firstVirtualStackIndex + virtualStackSlot.getId();
     }

 }
	/*
	* 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.trace;

	import static org.graalvm.compiler.lir.LIRValueUtil.asVirtualStackSlot;
	import static org.graalvm.compiler.lir.LIRValueUtil.isStackSlotValue;
	import static org.graalvm.compiler.lir.LIRValueUtil.isVirtualStackSlot;
	import static org.graalvm.compiler.lir.alloc.trace.TraceUtil.asShadowedRegisterValue;
	import static org.graalvm.compiler.lir.alloc.trace.TraceUtil.isShadowedRegisterValue;
	import static jdk.vm.ci.code.ValueUtil.asAllocatableValue;
	import static jdk.vm.ci.code.ValueUtil.asRegister;
	import static jdk.vm.ci.code.ValueUtil.asStackSlot;
	import static jdk.vm.ci.code.ValueUtil.isIllegal;
	import static jdk.vm.ci.code.ValueUtil.isRegister;
	import static jdk.vm.ci.code.ValueUtil.isStackSlot;

	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.HashSet;
	import java.util.List;

	import org.graalvm.compiler.core.common.LIRKind;
	import org.graalvm.compiler.debug.Debug;
	import org.graalvm.compiler.debug.DebugCounter;
	import org.graalvm.compiler.debug.GraalError;
	import org.graalvm.compiler.debug.Indent;
	import org.graalvm.compiler.lir.LIRInsertionBuffer;
	import org.graalvm.compiler.lir.LIRInstruction;
	import org.graalvm.compiler.lir.VirtualStackSlot;
	import org.graalvm.compiler.lir.framemap.FrameMap;
	import org.graalvm.compiler.lir.framemap.FrameMapBuilder;
	import org.graalvm.compiler.lir.framemap.FrameMapBuilderTool;
	import org.graalvm.compiler.lir.gen.LIRGenerationResult;
	import org.graalvm.compiler.lir.gen.LIRGeneratorTool.MoveFactory;

	import jdk.vm.ci.code.Architecture;
	import jdk.vm.ci.code.RegisterArray;
	import jdk.vm.ci.code.StackSlot;
	import jdk.vm.ci.meta.AllocatableValue;
	import jdk.vm.ci.meta.Value;

	/**
	*/
	public final class TraceGlobalMoveResolver extends TraceGlobalMoveResolutionPhase.MoveResolver {

	private static final DebugCounter cycleBreakingSlotsAllocated = Debug.counter("TraceRA[cycleBreakingSlotsAllocated(global)]");
	private static final DebugCounter cycleBreakingSlotsReused = Debug.counter("TraceRA[cycleBreakingSlotsReused(global)]");

	private int insertIdx;
	private LIRInsertionBuffer insertionBuffer; // buffer where moves are inserted

	private final List<Value> mappingFrom;
	private final List<Value> mappingFromStack;
	private final List<AllocatableValue> mappingTo;
	private final int[] registerBlocked;
	private static final int STACK_SLOT_IN_CALLER_FRAME_IDX = -1;
	private int[] stackBlocked;
	private final int firstVirtualStackIndex;
	private final MoveFactory spillMoveFactory;
	private final FrameMapBuilder frameMapBuilder;

	private void setValueBlocked(Value location, int direction) {
	assert direction == 1 \|\| direction == -1 : "out of bounds";
	if (isStackSlotValue(location)) {
	int stackIdx = getStackArrayIndex(location);
	if (stackIdx == STACK_SLOT_IN_CALLER_FRAME_IDX) {
	// incoming stack arguments can be ignored
	return;
	}
	if (stackIdx >= stackBlocked.length) {
	stackBlocked = Arrays.copyOf(stackBlocked, stackIdx + 1);
	}
	stackBlocked[stackIdx] += direction;
	} else {
	assert direction == 1 \|\| direction == -1 : "out of bounds";
	if (isRegister(location)) {
	registerBlocked[asRegister(location).number] += direction;
	} else {
	throw GraalError.shouldNotReachHere("unhandled value " + location);
	}
	}
	}

	private int valueBlocked(Value location) {
	if (isStackSlotValue(location)) {
	int stackIdx = getStackArrayIndex(location);
	if (stackIdx == STACK_SLOT_IN_CALLER_FRAME_IDX) {
	// incoming stack arguments are always blocked (aka they can not be written)
	return 1;
	}
	if (stackIdx >= stackBlocked.length) {
	return 0;
	}
	return stackBlocked[stackIdx];
	}
	if (isRegister(location)) {
	return registerBlocked[asRegister(location).number];
	}
	throw GraalError.shouldNotReachHere("unhandled value " + location);
	}

	private static boolean areMultipleReadsAllowed() {
	return true;
	}

	private boolean hasMappings() {
	return mappingFrom.size() > 0;
	}

	private MoveFactory getSpillMoveFactory() {
	return spillMoveFactory;
	}

	private RegisterArray getRegisters() {
	return frameMapBuilder.getRegisterConfig().getAllocatableRegisters();
	}

	public TraceGlobalMoveResolver(LIRGenerationResult res, MoveFactory spillMoveFactory, Architecture arch) {

	this.mappingFrom = new ArrayList<>(8);
	this.mappingFromStack = new ArrayList<>(8);
	this.mappingTo = new ArrayList<>(8);
	this.insertIdx = -1;
	this.insertionBuffer = new LIRInsertionBuffer();

	this.frameMapBuilder = res.getFrameMapBuilder();
	this.spillMoveFactory = spillMoveFactory;
	this.registerBlocked = new int[arch.getRegisters().size()];

	FrameMapBuilderTool frameMapBuilderTool = (FrameMapBuilderTool) frameMapBuilder;
	this.stackBlocked = new int[frameMapBuilderTool.getNumberOfStackSlots()];

	FrameMap frameMap = frameMapBuilderTool.getFrameMap();
	this.firstVirtualStackIndex = !frameMap.frameNeedsAllocating() ? 0 : frameMap.currentFrameSize() + 1;
	}

	private boolean checkEmpty() {
	for (int i = 0; i < stackBlocked.length; i++) {
	assert stackBlocked[i] == 0 : "stack map must be empty before and after processing";
	}
	assert mappingFrom.size() == 0 && mappingTo.size() == 0 && mappingFromStack.size() == 0 : "list must be empty before and after processing";
	for (int i = 0; i < getRegisters().size(); i++) {
	assert registerBlocked[i] == 0 : "register map must be empty before and after processing";
	}
	return true;
	}

	private boolean verifyBeforeResolve() {
	assert mappingFrom.size() == mappingTo.size() && mappingFrom.size() == mappingFromStack.size() : "length must be equal";
	assert insertIdx != -1 : "insert position not set";

	int i;
	int j;
	if (!areMultipleReadsAllowed()) {
	for (i = 0; i < mappingFrom.size(); i++) {
	for (j = i + 1; j < mappingFrom.size(); j++) {
	assert mappingFrom.get(i) == null \|\| mappingFrom.get(i) != mappingFrom.get(j) : "cannot read from same interval twice";
	}
	}
	}

	for (i = 0; i < mappingTo.size(); i++) {
	for (j = i + 1; j < mappingTo.size(); j++) {
	assert mappingTo.get(i) != mappingTo.get(j) : "cannot write to same interval twice";
	}
	}

	for (i = 0; i < mappingTo.size(); i++) {
	Value to = mappingTo.get(i);
	assert !isStackSlotValue(to) \|\| getStackArrayIndex(to) != STACK_SLOT_IN_CALLER_FRAME_IDX : "Cannot move to in argument: " + to;
	}

	HashSet<Value> usedRegs = new HashSet<>();
	if (!areMultipleReadsAllowed()) {
	for (i = 0; i < mappingFrom.size(); i++) {
	Value from = mappingFrom.get(i);
	if (from != null && !isIllegal(from)) {
	boolean unique = usedRegs.add(from);
	assert unique : "cannot read from same register twice";
	}
	}
	}

	usedRegs.clear();
	for (i = 0; i < mappingTo.size(); i++) {
	Value to = mappingTo.get(i);
	if (isIllegal(to)) {
	// After insertion the location may become illegal, so don't check it since multiple
	// intervals might be illegal.
	continue;
	}
	boolean unique = usedRegs.add(to);
	assert unique : "cannot write to same register twice";
	}

	return true;
	}

	// mark assignedReg and assignedRegHi of the interval as blocked
	private void block(Value location) {
	if (mightBeBlocked(location)) {
	assert areMultipleReadsAllowed() \|\| valueBlocked(location) == 0 : "location already marked as used: " + location;
	setValueBlocked(location, 1);
	Debug.log("block %s", location);
	}
	}

	// mark assignedReg and assignedRegHi of the interval as unblocked
	private void unblock(Value location) {
	if (mightBeBlocked(location)) {
	assert valueBlocked(location) > 0 : "location already marked as unused: " + location;
	setValueBlocked(location, -1);
	Debug.log("unblock %s", location);
	}
	}

	/**
	* Checks if {@code to} is not blocked or is only blocked by {@code from}.
	*/
	private boolean safeToProcessMove(Value fromLocation, Value toLocation) {
	if (mightBeBlocked(toLocation)) {
	if ((valueBlocked(toLocation) > 1 \|\| (valueBlocked(toLocation) == 1 && !isMoveToSelf(fromLocation, toLocation)))) {
	return false;
	}
	}

	return true;
	}

	public static boolean isMoveToSelf(Value from, Value to) {
	assert to != null;
	if (to.equals(from)) {
	return true;
	}
	if (from == null) {
	return false;
	}
	if (isShadowedRegisterValue(from)) {
	/* From is a shadowed register. */
	if (isShadowedRegisterValue(to)) {
	// both shadowed but not equal
	return false;
	}
	ShadowedRegisterValue shadowed = asShadowedRegisterValue(from);
	if (isRegisterToRegisterMoveToSelf(shadowed.getRegister(), to)) {
	return true;
	}
	if (isStackSlotValue(to)) {
	return to.equals(shadowed.getStackSlot());
	}
	} else {
	/*
	* A shadowed destination value is never a self move it both values are not equal. Fall
	* through.
	*/
	// if (isShadowedRegisterValue(to)) return false;

	return isRegisterToRegisterMoveToSelf(from, to);
	}
	return false;
	}

	private static boolean isRegisterToRegisterMoveToSelf(Value from, Value to) {
	if (to.equals(from)) {
	return true;
	}
	if (isRegister(from) && isRegister(to) && asRegister(from).equals(asRegister(to))) {
	// Values differ but Registers are the same
	assert LIRKind.verifyMoveKinds(to.getValueKind(), from.getValueKind()) : String.format("Same register but Kind mismatch %s <- %s", to, from);
	return true;
	}
	return false;
	}

	private static boolean mightBeBlocked(Value location) {
	return isRegister(location) \|\| isStackSlotValue(location);
	}

	private void createInsertionBuffer(List<LIRInstruction> list) {
	assert !insertionBuffer.initialized() : "overwriting existing buffer";
	insertionBuffer.init(list);
	}

	private void appendInsertionBuffer() {
	if (insertionBuffer.initialized()) {
	insertionBuffer.finish();
	}
	assert !insertionBuffer.initialized() : "must be uninitialized now";

	insertIdx = -1;
	}

	private void insertMove(Value fromOperand, AllocatableValue toOperand) {
	assert !fromOperand.equals(toOperand) : "from and to are equal: " + fromOperand + " vs. " + toOperand;
	assert LIRKind.verifyMoveKinds(fromOperand.getValueKind(), fromOperand.getValueKind()) : "move between different types";
	assert insertIdx != -1 : "must setup insert position first";

	insertionBuffer.append(insertIdx, createMove(fromOperand, toOperand));

	if (Debug.isLogEnabled()) {
	Debug.log("insert move from %s to %s at %d", fromOperand, toOperand, insertIdx);
	}
	}

	/**
	* @param fromOpr Operand of the {@code from} interval
	* @param toOpr Operand of the {@code to} interval
	*/
	private LIRInstruction createMove(Value fromOpr, AllocatableValue toOpr) {
	if (isStackSlotValue(toOpr) && isStackSlotValue(fromOpr)) {
	return getSpillMoveFactory().createStackMove(toOpr, asAllocatableValue(fromOpr));
	}
	return getSpillMoveFactory().createMove(toOpr, fromOpr);
	}

	@SuppressWarnings("try")
	private void resolveMappings() {
	try (Indent indent = Debug.logAndIndent("resolveMapping")) {
	assert verifyBeforeResolve();
	if (Debug.isLogEnabled()) {
	printMapping();
	}

	// Block all registers that are used as input operands of a move.
	// When a register is blocked, no move to this register is emitted.
	// This is necessary for detecting cycles in moves.
	for (int i = mappingFrom.size() - 1; i >= 0; i--) {
	Value from = mappingFrom.get(i);
	block(from);
	}

	ArrayList<AllocatableValue> busySpillSlots = null;
	while (mappingFrom.size() > 0) {
	boolean processedInterval = false;

	int spillCandidate = -1;
	for (int i = mappingFrom.size() - 1; i >= 0; i--) {
	Value fromLocation = mappingFrom.get(i);
	AllocatableValue toLocation = mappingTo.get(i);
	if (safeToProcessMove(fromLocation, toLocation)) {
	// this interval can be processed because target is free
	insertMove(fromLocation, toLocation);
	unblock(fromLocation);
	if (isStackSlotValue(toLocation)) {
	if (busySpillSlots == null) {
	busySpillSlots = new ArrayList<>(2);
	}
	busySpillSlots.add(toLocation);
	}
	mappingFrom.remove(i);
	mappingFromStack.remove(i);
	mappingTo.remove(i);

	processedInterval = true;
	} else if (fromLocation != null) {
	if (isRegister(fromLocation) && (busySpillSlots == null \|\| !busySpillSlots.contains(mappingFromStack.get(i)))) {
	// this interval cannot be processed now because target is not free
	// it starts in a register, so it is a possible candidate for spilling
	spillCandidate = i;
	} else if (isStackSlotValue(fromLocation) && spillCandidate == -1) {
	// fall back to spill a stack slot in case no other candidate is found
	spillCandidate = i;
	}
	}
	}

	if (!processedInterval) {
	breakCycle(spillCandidate);
	}
	}
	}

	// check that all intervals have been processed
	assert checkEmpty();
	}

	@SuppressWarnings("try")
	private void breakCycle(int spillCandidate) {
	// no move could be processed because there is a cycle in the move list
	// (e.g. r1 . r2, r2 . r1), so one interval must be spilled to memory
	assert spillCandidate != -1 : "no interval in register for spilling found";

	// create a new spill interval and assign a stack slot to it
	Value from = mappingFrom.get(spillCandidate);
	try (Indent indent = Debug.logAndIndent("BreakCycle: %s", from)) {
	AllocatableValue spillSlot = null;
	if (TraceRegisterAllocationPhase.Options.TraceRAreuseStackSlotsForMoveResolutionCycleBreaking.getValue() && !isStackSlotValue(from)) {
	// don't use the stack slot if from is already the stack slot
	Value fromStack = mappingFromStack.get(spillCandidate);
	if (fromStack != null) {
	spillSlot = (AllocatableValue) fromStack;
	cycleBreakingSlotsReused.increment();
	Debug.log("reuse slot for spilling: %s", spillSlot);
	}
	}
	if (spillSlot == null) {
	spillSlot = frameMapBuilder.allocateSpillSlot(from.getValueKind());
	cycleBreakingSlotsAllocated.increment();
	Debug.log("created new slot for spilling: %s", spillSlot);
	// insert a move from register to stack and update the mapping
	insertMove(from, spillSlot);
	}
	block(spillSlot);
	mappingFrom.set(spillCandidate, spillSlot);
	unblock(from);
	}
	}

	@SuppressWarnings("try")
	private void printMapping() {
	try (Indent indent = Debug.logAndIndent("Mapping")) {
	for (int i = mappingFrom.size() - 1; i >= 0; i--) {
	Debug.log("move %s <- %s (%s)", mappingTo.get(i), mappingFrom.get(i), mappingFromStack.get(i));
	}
	}
	}

	public void setInsertPosition(List<LIRInstruction> insertList, int insertIdx) {
	assert this.insertIdx == -1 : "use moveInsertPosition instead of setInsertPosition when data already set";

	createInsertionBuffer(insertList);
	this.insertIdx = insertIdx;
	}

	@Override
	public void addMapping(Value from, AllocatableValue to, Value fromStack) {
	if (Debug.isLogEnabled()) {
	Debug.log("add move mapping from %s to %s", from, to);
	}

	assert !from.equals(to) : "from and to interval equal: " + from;
	assert LIRKind.verifyMoveKinds(to.getValueKind(), from.getValueKind()) : String.format("Kind mismatch: %s vs. %s, from=%s, to=%s", from.getValueKind(), to.getValueKind(), from, to);
	assert fromStack == null \|\| LIRKind.verifyMoveKinds(to.getValueKind(), fromStack.getValueKind()) : String.format("Kind mismatch: %s vs. %s, fromStack=%s, to=%s", fromStack.getValueKind(),
	to.getValueKind(), fromStack, to);
	mappingFrom.add(from);
	mappingFromStack.add(fromStack);
	mappingTo.add(to);
	}

	public void resolveAndAppendMoves() {
	if (hasMappings()) {
	resolveMappings();
	}
	appendInsertionBuffer();
	}

	private int getStackArrayIndex(Value stackSlotValue) {
	if (isStackSlot(stackSlotValue)) {
	return getStackArrayIndex(asStackSlot(stackSlotValue));
	}
	if (isVirtualStackSlot(stackSlotValue)) {
	return getStackArrayIndex(asVirtualStackSlot(stackSlotValue));
	}
	throw GraalError.shouldNotReachHere("value is not a stack slot: " + stackSlotValue);
	}

	private int getStackArrayIndex(StackSlot stackSlot) {
	int stackIdx;
	if (stackSlot.isInCallerFrame()) {
	// incoming stack arguments can be ignored
	stackIdx = STACK_SLOT_IN_CALLER_FRAME_IDX;
	} else {
	assert stackSlot.getRawAddFrameSize() : "Unexpected stack slot: " + stackSlot;
	int offset = -stackSlot.getRawOffset();
	assert 0 <= offset && offset < firstVirtualStackIndex : String.format("Wrong stack slot offset: %d (first virtual stack slot index: %d", offset, firstVirtualStackIndex);
	stackIdx = offset;
	}
	return stackIdx;
	}

	private int getStackArrayIndex(VirtualStackSlot virtualStackSlot) {
	return firstVirtualStackIndex + virtualStackSlot.getId();
	}

	}