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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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
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 *
 * 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.
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package org.graalvm.compiler.lir.aarch64;

import static jdk.vm.ci.code.ValueUtil.asAllocatableValue;
import static jdk.vm.ci.code.ValueUtil.asRegister;

import java.util.function.Function;

import org.graalvm.compiler.asm.Label;
import org.graalvm.compiler.asm.NumUtil;
import org.graalvm.compiler.asm.aarch64.AArch64Address;
import org.graalvm.compiler.asm.aarch64.AArch64Assembler;
import org.graalvm.compiler.asm.aarch64.AArch64Assembler.ConditionFlag;
import org.graalvm.compiler.asm.aarch64.AArch64MacroAssembler;
import org.graalvm.compiler.asm.aarch64.AArch64MacroAssembler.PatchLabelKind;
import org.graalvm.compiler.code.CompilationResult.JumpTable;
import org.graalvm.compiler.core.common.LIRKind;
import org.graalvm.compiler.core.common.calc.Condition;
import org.graalvm.compiler.debug.GraalError;
import org.graalvm.compiler.lir.ConstantValue;
import org.graalvm.compiler.lir.LIRInstructionClass;
import org.graalvm.compiler.lir.LabelRef;
import org.graalvm.compiler.lir.Opcode;
import org.graalvm.compiler.lir.StandardOp;
import org.graalvm.compiler.lir.SwitchStrategy;
import org.graalvm.compiler.lir.SwitchStrategy.BaseSwitchClosure;
import org.graalvm.compiler.lir.Variable;
import org.graalvm.compiler.lir.asm.CompilationResultBuilder;

import jdk.vm.ci.aarch64.AArch64Kind;
import jdk.vm.ci.code.Register;
import jdk.vm.ci.meta.Constant;
import jdk.vm.ci.meta.JavaConstant;
import jdk.vm.ci.meta.Value;

public class AArch64ControlFlow {

    
Compares integer register to 0 and branches if condition is true. Condition may only be equal or non-equal.
/** * Compares integer register to 0 and branches if condition is true. Condition may only be equal * or non-equal. */
// TODO (das) where do we need this? // public static class CompareAndBranchOp extends AArch64LIRInstruction implements // StandardOp.BranchOp { // private final ConditionFlag condition; // private final LabelRef destination; // @Use({REG}) private Value x; // // public CompareAndBranchOp(Condition condition, LabelRef destination, Value x) { // assert condition == Condition.EQ || condition == Condition.NE; // assert ARMv8.isGpKind(x.getKind()); // this.condition = condition == Condition.EQ ? ConditionFlag.EQ : ConditionFlag.NE; // this.destination = destination; // this.x = x; // } // // @Override // public void emitCode(CompilationResultBuilder crb, ARMv8MacroAssembler masm) { // int size = ARMv8.bitsize(x.getKind()); // if (condition == ConditionFlag.EQ) { // masm.cbz(size, asRegister(x), destination.label()); // } else { // masm.cbnz(size, asRegister(x), destination.label()); // } // } // } public static class BranchOp extends AArch64BlockEndOp implements StandardOp.BranchOp { public static final LIRInstructionClass<BranchOp> TYPE = LIRInstructionClass.create(BranchOp.class); private final AArch64Assembler.ConditionFlag condition; private final LabelRef trueDestination; private final LabelRef falseDestination; private final double trueDestinationProbability; public BranchOp(AArch64Assembler.ConditionFlag condition, LabelRef trueDestination, LabelRef falseDestination, double trueDestinationProbability) { super(TYPE); this.condition = condition; this.trueDestination = trueDestination; this.falseDestination = falseDestination; this.trueDestinationProbability = trueDestinationProbability; } @Override public void emitCode(CompilationResultBuilder crb, AArch64MacroAssembler masm) { /* * Explanation: Depending on what the successor edge is, we can use the fall-through to * optimize the generated code. If neither is a successor edge, use the branch * probability to try to take the conditional jump as often as possible to avoid * executing two instructions instead of one. */ if (crb.isSuccessorEdge(trueDestination)) { masm.branchConditionally(condition.negate(), falseDestination.label()); } else if (crb.isSuccessorEdge(falseDestination)) { masm.branchConditionally(condition, trueDestination.label()); } else if (trueDestinationProbability < 0.5) { masm.branchConditionally(condition.negate(), falseDestination.label()); masm.jmp(trueDestination.label()); } else { masm.branchConditionally(condition, trueDestination.label()); masm.jmp(falseDestination.label()); } } } @Opcode("CMOVE") public static class CondMoveOp extends AArch64LIRInstruction { public static final LIRInstructionClass<CondMoveOp> TYPE = LIRInstructionClass.create(CondMoveOp.class); @Def protected Value result; @Use protected Value trueValue; @Use protected Value falseValue; private final AArch64Assembler.ConditionFlag condition; public CondMoveOp(Variable result, AArch64Assembler.ConditionFlag condition, Value trueValue, Value falseValue) { super(TYPE); assert trueValue.getPlatformKind() == falseValue.getPlatformKind() && trueValue.getPlatformKind() == result.getPlatformKind(); this.result = result; this.condition = condition; this.trueValue = trueValue; this.falseValue = falseValue; } @Override public void emitCode(CompilationResultBuilder crb, AArch64MacroAssembler masm) { AArch64Kind kind = (AArch64Kind) trueValue.getPlatformKind(); int size = kind.getSizeInBytes() * Byte.SIZE; if (kind.isInteger()) { masm.cmov(size, asRegister(result), asRegister(trueValue), asRegister(falseValue), condition); } else { masm.fcmov(size, asRegister(result), asRegister(trueValue), asRegister(falseValue), condition); } } } public static class StrategySwitchOp extends AArch64BlockEndOp implements StandardOp.BlockEndOp { public static final LIRInstructionClass<StrategySwitchOp> TYPE = LIRInstructionClass.create(StrategySwitchOp.class); private final Constant[] keyConstants; protected final SwitchStrategy strategy; private final Function<Condition, ConditionFlag> converter; private final LabelRef[] keyTargets; private final LabelRef defaultTarget; @Alive protected Value key; // TODO (das) This could be optimized: We only need the scratch register in case of a // datapatch, or too large immediates. @Temp protected Value scratch; public StrategySwitchOp(SwitchStrategy strategy, LabelRef[] keyTargets, LabelRef defaultTarget, Value key, Value scratch, Function<Condition, ConditionFlag> converter) { this(TYPE, strategy, keyTargets, defaultTarget, key, scratch, converter); } protected StrategySwitchOp(LIRInstructionClass<? extends StrategySwitchOp> c, SwitchStrategy strategy, LabelRef[] keyTargets, LabelRef defaultTarget, Value key, Value scratch, Function<Condition, ConditionFlag> converter) { super(c); this.strategy = strategy; this.converter = converter; this.keyConstants = strategy.getKeyConstants(); this.keyTargets = keyTargets; this.defaultTarget = defaultTarget; this.key = key; this.scratch = scratch; assert keyConstants.length == keyTargets.length; assert keyConstants.length == strategy.keyProbabilities.length; } @Override public void emitCode(CompilationResultBuilder crb, AArch64MacroAssembler masm) { strategy.run(new SwitchClosure(asRegister(key), crb, masm)); } public class SwitchClosure extends BaseSwitchClosure { protected final Register keyRegister; protected final CompilationResultBuilder crb; protected final AArch64MacroAssembler masm; protected SwitchClosure(Register keyRegister, CompilationResultBuilder crb, AArch64MacroAssembler masm) { super(crb, masm, keyTargets, defaultTarget); this.keyRegister = keyRegister; this.crb = crb; this.masm = masm; } protected void emitComparison(Constant c) { JavaConstant jc = (JavaConstant) c; ConstantValue constVal = new ConstantValue(LIRKind.value(key.getPlatformKind()), c); switch (jc.getJavaKind()) { case Int: long lc = jc.asLong(); assert NumUtil.isInt(lc); emitCompare(crb, masm, key, scratch, constVal); break; case Long: emitCompare(crb, masm, key, scratch, constVal); break; case Object: emitCompare(crb, masm, key, scratch, constVal); break; default: throw new GraalError("switch only supported for int, long and object"); } } @Override protected void conditionalJump(int index, Condition condition, Label target) { emitComparison(keyConstants[index]); masm.branchConditionally(converter.apply(condition), target); } } } public static class TableSwitchOp extends AArch64BlockEndOp implements StandardOp.BlockEndOp { public static final LIRInstructionClass<TableSwitchOp> TYPE = LIRInstructionClass.create(TableSwitchOp.class); private final int lowKey; private final LabelRef defaultTarget; private final LabelRef[] targets; @Alive protected Variable keyValue; @Temp protected Variable scratchValue; public TableSwitchOp(int lowKey, LabelRef defaultTarget, LabelRef[] targets, Variable key, Variable scratch) { super(TYPE); this.lowKey = lowKey; this.defaultTarget = defaultTarget; this.targets = targets; this.keyValue = key; this.scratchValue = scratch; } @Override public void emitCode(CompilationResultBuilder crb, AArch64MacroAssembler masm) { Register key = asRegister(keyValue); Register scratch = asRegister(scratchValue); if (lowKey != 0) { if (AArch64MacroAssembler.isArithmeticImmediate(lowKey)) { masm.sub(32, key, key, lowKey); } else { ConstantValue constVal = new ConstantValue(LIRKind.value(AArch64Kind.WORD), JavaConstant.forInt(lowKey)); AArch64Move.move(crb, masm, scratchValue, constVal); masm.sub(32, key, key, scratch); } } if (defaultTarget != null) { // if key is not in table range, jump to default target if it exists. ConstantValue constVal = new ConstantValue(LIRKind.value(AArch64Kind.WORD), JavaConstant.forInt(targets.length)); emitCompare(crb, masm, keyValue, scratchValue, constVal); masm.branchConditionally(AArch64Assembler.ConditionFlag.HS, defaultTarget.label()); } // Load the start address of the jump table - which starts 3 instructions after the adr // - into scratch. masm.adr(scratch, 4 * 3); masm.ldr(32, scratch, AArch64Address.createRegisterOffsetAddress(scratch, key, /* scaled */true)); masm.jmp(scratch); int jumpTablePos = masm.position(); // emit jump table entries for (LabelRef target : targets) { Label label = target.label(); if (label.isBound()) { masm.emitInt(target.label().position()); } else { label.addPatchAt(masm.position()); masm.emitInt(PatchLabelKind.JUMP_ADDRESS.encoding); } } JumpTable jt = new JumpTable(jumpTablePos, lowKey, lowKey + targets.length - 1, 4); crb.compilationResult.addAnnotation(jt); } } private static void emitCompare(CompilationResultBuilder crb, AArch64MacroAssembler masm, Value key, Value scratchValue, ConstantValue c) { long imm = c.getJavaConstant().asLong(); final int size = key.getPlatformKind().getSizeInBytes() * Byte.SIZE; if (AArch64MacroAssembler.isComparisonImmediate(imm)) { masm.cmp(size, asRegister(key), (int) imm); } else { AArch64Move.move(crb, masm, asAllocatableValue(scratchValue), c); masm.cmp(size, asRegister(key), asRegister(scratchValue)); } } }