org.graalvm.compiler.lir.alloc.lsra.LinearScanAssignLocationsPhase Maven / Gradle / Ivy
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package org.graalvm.compiler.lir.alloc.lsra;
import static jdk.vm.ci.code.ValueUtil.isIllegal;
import static org.graalvm.compiler.lir.LIRValueUtil.asVariable;
import static org.graalvm.compiler.lir.LIRValueUtil.changeValueKind;
import static org.graalvm.compiler.lir.LIRValueUtil.isCast;
import static org.graalvm.compiler.lir.LIRValueUtil.isJavaConstant;
import static org.graalvm.compiler.lir.LIRValueUtil.isStackSlotValue;
import static org.graalvm.compiler.lir.LIRValueUtil.isVariable;
import static org.graalvm.compiler.lir.LIRValueUtil.isVirtualStackSlot;
import java.util.ArrayList;
import java.util.Collections;
import java.util.EnumSet;
import org.graalvm.compiler.core.common.cfg.BasicBlock;
import org.graalvm.compiler.debug.DebugContext;
import org.graalvm.compiler.debug.GraalError;
import org.graalvm.compiler.debug.Indent;
import org.graalvm.compiler.lir.CastValue;
import org.graalvm.compiler.lir.ConstantValue;
import org.graalvm.compiler.lir.InstructionValueProcedure;
import org.graalvm.compiler.lir.LIRInstruction;
import org.graalvm.compiler.lir.LIRInstruction.OperandFlag;
import org.graalvm.compiler.lir.LIRInstruction.OperandMode;
import org.graalvm.compiler.lir.StandardOp;
import org.graalvm.compiler.lir.StandardOp.MoveOp;
import org.graalvm.compiler.lir.StandardOp.ValueMoveOp;
import org.graalvm.compiler.lir.Variable;
import org.graalvm.compiler.lir.gen.LIRGenerationResult;
import org.graalvm.compiler.lir.phases.AllocationPhase.AllocationContext;
import jdk.vm.ci.code.TargetDescription;
import jdk.vm.ci.code.ValueUtil;
import jdk.vm.ci.meta.AllocatableValue;
import jdk.vm.ci.meta.Value;
/**
* Phase 7: Assign register numbers back to LIR.
*/
public class LinearScanAssignLocationsPhase extends LinearScanAllocationPhase {
protected final LinearScan allocator;
public LinearScanAssignLocationsPhase(LinearScan allocator) {
this.allocator = allocator;
}
@Override
protected void run(TargetDescription target, LIRGenerationResult lirGenRes, AllocationContext context) {
assignLocations();
}
/**
* Assigns the allocated location for an LIR instruction operand back into the instruction.
*
* @param op current {@link LIRInstruction}
* @param operand an LIR instruction operand
* @param mode the usage mode for {@code operand} by the instruction
* @return the location assigned for the operand
*/
protected Value colorLirOperand(LIRInstruction op, Variable operand, OperandMode mode) {
int opId = op.id();
Interval interval = allocator.intervalFor(operand);
assert interval != null : "interval must exist";
if (opId != -1) {
if (allocator.detailedAsserts) {
BasicBlock block = allocator.blockForId(opId);
if (block.getSuccessorCount() <= 1 && opId == allocator.getLastLirInstructionId(block)) {
/*
* Check if spill moves could have been appended at the end of this block, but
* before the branch instruction. So the split child information for this branch
* would be incorrect.
*/
LIRInstruction instr = allocator.getLIR().getLIRforBlock(block).get(allocator.getLIR().getLIRforBlock(block).size() - 1);
if (instr instanceof StandardOp.JumpOp) {
if (allocator.getBlockData(block).liveOut.get(allocator.operandNumber(operand))) {
assert false : String.format(
"can't get split child for the last branch of a block because the information would be incorrect (moves are inserted before the branch in resolveDataFlow) block=%s, instruction=%s, operand=%s",
block, instr, operand);
}
}
}
}
/*
* Operands are not changed when an interval is split during allocation, so search the
* right interval here.
*/
interval = allocator.splitChildAtOpId(interval, opId, mode);
}
if (isIllegal(interval.location()) && interval.canMaterialize()) {
assert mode != OperandMode.DEF;
return new ConstantValue(interval.kind(), interval.getMaterializedValue());
}
return interval.location();
}
private Value debugInfoProcedure(LIRInstruction op, Value operand) {
if (isVirtualStackSlot(operand) || ValueUtil.isRegister(operand)) {
return operand;
}
int tempOpId = op.id();
OperandMode mode = OperandMode.USE;
BasicBlock block = allocator.blockForId(tempOpId);
if (block.getSuccessorCount() == 1 && tempOpId == allocator.getLastLirInstructionId(block)) {
/*
* Generating debug information for the last instruction of a block. If this instruction
* is a branch, spill moves are inserted before this branch and so the wrong operand
* would be returned (spill moves at block boundaries are not considered in the live
* ranges of intervals).
*
* Solution: use the first opId of the branch target block instead.
*/
final LIRInstruction instr = allocator.getLIR().getLIRforBlock(block).get(allocator.getLIR().getLIRforBlock(block).size() - 1);
if (instr instanceof StandardOp.JumpOp) {
if (allocator.getBlockData(block).liveOut.get(allocator.operandNumber(operand))) {
tempOpId = allocator.getFirstLirInstructionId(block.getSuccessorAt(0));
mode = OperandMode.DEF;
}
}
}
/*
* Get current location of operand. The operand must be live because debug information is
* considered when building the intervals if the interval is not live, colorLirOperand will
* cause an assert on failure.
*/
Value result = colorLirOperand(op, asVariable(operand), mode);
assert !allocator.hasCall(tempOpId) || isStackSlotValue(result) || isJavaConstant(result) || !allocator.isCallerSave(result) : "cannot have caller-save register operands at calls";
return result;
}
private void assignLocations(ArrayList instructions) {
int numInst = instructions.size();
boolean hasDead = false;
for (int j = 0; j < numInst; j++) {
final LIRInstruction op = instructions.get(j);
if (op == null) {
/*
* this can happen when spill-moves are removed in eliminateSpillMoves
*/
hasDead = true;
} else {
try {
LIRInstruction newOp = assignLocations(op);
if (op != newOp) {
instructions.set(j, newOp);
}
if (newOp == null) {
hasDead = true;
}
} catch (GraalError e) {
throw e.addContext("lir instruction", "@" + op.id() + " " + op.getClass().getName() + " " + op);
}
}
}
if (hasDead) {
// Remove null values from the list.
instructions.removeAll(Collections.singleton(null));
}
}
private final InstructionValueProcedure assignProc = new InstructionValueProcedure() {
@Override
public Value doValue(LIRInstruction instruction, Value value, OperandMode mode, EnumSet flags) {
if (isVariable(value)) {
Value location = colorLirOperand(instruction, asVariable(value), mode);
if (isCast(value)) {
GraalError.guarantee(mode == LIRInstruction.OperandMode.USE || mode == LIRInstruction.OperandMode.ALIVE, "Invalid application of CastValue");
// return the same location, but with the cast's kind.
CastValue cast = (CastValue) value;
return changeValueKind(location, cast.getValueKind(), true);
}
return location;
} else if (isCast(value)) {
GraalError.guarantee(mode == LIRInstruction.OperandMode.USE || mode == LIRInstruction.OperandMode.ALIVE, "Invalid application of CastValue");
// strip CastValue: return underlying value, but with the cast's kind.
CastValue cast = (CastValue) value;
return changeValueKind(cast.underlyingValue(), cast.getValueKind(), false);
}
return value;
}
};
private final InstructionValueProcedure debugInfoProc = new InstructionValueProcedure() {
@Override
public Value doValue(LIRInstruction instruction, Value value, OperandMode mode, EnumSet flags) {
return debugInfoProcedure(instruction, value);
}
};
/**
* Assigns the operand of an {@link LIRInstruction}.
*
* @param inputOp The {@link LIRInstruction} that should be colored.
* @return the {@link LIRInstruction} that should be emitted. A {@code null} return deletes the
* instruction.
*/
protected LIRInstruction assignLocations(LIRInstruction inputOp) {
assert inputOp != null;
LIRInstruction op = inputOp;
// remove useless moves
if (MoveOp.isMoveOp(op)) {
AllocatableValue result = MoveOp.asMoveOp(op).getResult();
if (isVariable(result) && allocator.isMaterialized(result, op.id(), OperandMode.DEF)) {
/*
* This happens if a materializable interval is originally not spilled but then
* kicked out in LinearScanWalker.splitForSpilling(). When kicking out such an
* interval this move operation was already generated.
*/
return null;
}
}
if (ValueMoveOp.isValueMoveOp(op)) {
ValueMoveOp valueMoveOp = ValueMoveOp.asValueMoveOp(op);
AllocatableValue input = valueMoveOp.getInput();
if (isVariable(input)) {
Value inputOperand = colorLirOperand(op, asVariable(input), OperandMode.USE);
if (inputOperand instanceof ConstantValue) {
// Replace the ValueMoveOp with a constant materialization
op = allocator.getSpillMoveFactory().createLoad(valueMoveOp.getResult(), ((ConstantValue) inputOperand).getConstant());
}
}
}
op.forEachInput(assignProc);
op.forEachAlive(assignProc);
op.forEachTemp(assignProc);
op.forEachOutput(assignProc);
// compute reference map and debug information
op.forEachState(debugInfoProc);
// remove useless moves
if (ValueMoveOp.isValueMoveOp(op)) {
ValueMoveOp move = ValueMoveOp.asValueMoveOp(op);
if (move.getInput().equals(move.getResult())) {
return null;
}
}
return op;
}
@SuppressWarnings("try")
private void assignLocations() {
DebugContext debug = allocator.getDebug();
try (Indent indent = debug.logAndIndent("assign locations")) {
for (int blockId : allocator.sortedBlocks()) {
BasicBlock block = allocator.getLIR().getBlockById(blockId);
try (Indent indent2 = debug.logAndIndent("assign locations in block B%d", block.getId())) {
assignLocations(allocator.getLIR().getLIRforBlock(block));
}
}
}
}
}
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