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* 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).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
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package org.graalvm.compiler.lir.alloc.lsra.ssa;
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 jdk.vm.ci.code.ValueUtil.asStackSlot;
import static jdk.vm.ci.code.ValueUtil.isStackSlot;
import java.util.Arrays;
import org.graalvm.compiler.debug.GraalError;
import org.graalvm.compiler.lir.LIRInstruction;
import org.graalvm.compiler.lir.VirtualStackSlot;
import org.graalvm.compiler.lir.alloc.lsra.Interval;
import org.graalvm.compiler.lir.alloc.lsra.LinearScan;
import org.graalvm.compiler.lir.alloc.lsra.MoveResolver;
import org.graalvm.compiler.lir.framemap.FrameMap;
import org.graalvm.compiler.lir.framemap.FrameMapBuilderTool;
import jdk.vm.ci.code.StackSlot;
import jdk.vm.ci.meta.AllocatableValue;
import jdk.vm.ci.meta.Value;
public final class SSAMoveResolver extends MoveResolver {
private static final int STACK_SLOT_IN_CALLER_FRAME_IDX = -1;
private int[] stackBlocked;
private final int firstVirtualStackIndex;
public SSAMoveResolver(LinearScan allocator) {
super(allocator);
FrameMapBuilderTool frameMapBuilderTool = (FrameMapBuilderTool) allocator.getFrameMapBuilder();
FrameMap frameMap = frameMapBuilderTool.getFrameMap();
this.stackBlocked = new int[frameMapBuilderTool.getNumberOfStackSlots()];
this.firstVirtualStackIndex = !frameMap.frameNeedsAllocating() ? 0 : frameMap.currentFrameSize() + 1;
}
@Override
public boolean checkEmpty() {
for (int i = 0; i < stackBlocked.length; i++) {
assert stackBlocked[i] == 0 : "stack map must be empty before and after processing";
}
return super.checkEmpty();
}
@Override
protected void checkMultipleReads() {
// multiple reads are allowed in SSA LSRA
}
@Override
protected void verifyStackSlotMapping() {
// relax disjoint stack maps invariant
}
@Override
protected boolean areMultipleReadsAllowed() {
return true;
}
@Override
protected boolean mightBeBlocked(Value location) {
if (super.mightBeBlocked(location)) {
return true;
}
if (isStackSlotValue(location)) {
return true;
}
return false;
}
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();
}
@Override
protected 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 {
super.setValueBlocked(location, direction);
}
}
@Override
protected 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];
}
return super.valueBlocked(location);
}
@Override
protected LIRInstruction createMove(AllocatableValue fromOpr, AllocatableValue toOpr, AllocatableValue fromLocation, AllocatableValue toLocation) {
if (isStackSlotValue(toLocation) && isStackSlotValue(fromLocation)) {
return getAllocator().getSpillMoveFactory().createStackMove(toOpr, fromOpr);
}
return super.createMove(fromOpr, toOpr, fromLocation, toLocation);
}
@Override
protected void breakCycle(int spillCandidate) {
if (spillCandidate != -1) {
super.breakCycle(spillCandidate);
return;
}
assert mappingFromSize() > 1;
// Arbitrarily select the first entry for spilling.
int stackSpillCandidate = 0;
Interval fromInterval = getMappingFrom(stackSpillCandidate);
// allocate new stack slot
VirtualStackSlot spillSlot = getAllocator().getFrameMapBuilder().allocateSpillSlot(fromInterval.kind());
spillInterval(stackSpillCandidate, fromInterval, spillSlot);
}
}