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package org.graalvm.compiler.hotspot.amd64;

import static jdk.vm.ci.amd64.AMD64.rax;
import static jdk.vm.ci.amd64.AMD64.rip;
import static org.graalvm.compiler.core.common.GraalOptions.GeneratePIC;
import static org.graalvm.compiler.core.common.GraalOptions.ImmutableCode;
import static org.graalvm.compiler.core.common.NumUtil.isInt;

import org.graalvm.compiler.asm.amd64.AMD64Address;
import org.graalvm.compiler.asm.amd64.AMD64MacroAssembler;
import org.graalvm.compiler.core.common.LIRKind;
import org.graalvm.compiler.hotspot.GraalHotSpotVMConfig;
import org.graalvm.compiler.hotspot.HotSpotMarkId;
import org.graalvm.compiler.lir.LIRFrameState;
import org.graalvm.compiler.lir.LIRInstructionClass;
import org.graalvm.compiler.lir.Opcode;
import org.graalvm.compiler.lir.amd64.AMD64LIRInstruction;
import org.graalvm.compiler.lir.asm.CompilationResultBuilder;
import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool;

import jdk.vm.ci.code.Register;
import jdk.vm.ci.code.RegisterValue;
import jdk.vm.ci.code.site.InfopointReason;
import jdk.vm.ci.meta.AllocatableValue;
import jdk.vm.ci.meta.JavaConstant;
import jdk.vm.ci.meta.JavaKind;
import jdk.vm.ci.meta.Value;

Emits a safepoint poll.
/** * Emits a safepoint poll. */
@Opcode("SAFEPOINT") public final class AMD64HotSpotSafepointOp extends AMD64LIRInstruction { public static final LIRInstructionClass<AMD64HotSpotSafepointOp> TYPE = LIRInstructionClass.create(AMD64HotSpotSafepointOp.class); @State protected LIRFrameState state; @Temp({OperandFlag.REG, OperandFlag.ILLEGAL}) private AllocatableValue temp; private final GraalHotSpotVMConfig config; private final Register thread; public AMD64HotSpotSafepointOp(LIRFrameState state, GraalHotSpotVMConfig config, NodeLIRBuilderTool tool, Register thread) { super(TYPE); this.state = state; this.config = config; this.thread = thread; if (config.useThreadLocalPolling || isPollingPageFar(config) || ImmutableCode.getValue(tool.getOptions())) { temp = tool.getLIRGeneratorTool().newVariable(LIRKind.value(tool.getLIRGeneratorTool().target().arch.getWordKind())); } else { // Don't waste a register if it's unneeded temp = Value.ILLEGAL; } } @Override public void emitCode(CompilationResultBuilder crb, AMD64MacroAssembler asm) { emitCode(crb, asm, config, false, state, thread, temp instanceof RegisterValue ? ((RegisterValue) temp).getRegister() : null); } public static void emitCode(CompilationResultBuilder crb, AMD64MacroAssembler asm, GraalHotSpotVMConfig config, boolean atReturn, LIRFrameState state, Register thread, Register scratch) { if (config.useThreadLocalPolling) { emitThreadLocalPoll(crb, asm, config, atReturn, state, thread, scratch); } else { emitGlobalPoll(crb, asm, config, atReturn, state, scratch); } }
Tests if the polling page address can be reached from the code cache with 32-bit displacements.
/** * Tests if the polling page address can be reached from the code cache with 32-bit * displacements. */
private static boolean isPollingPageFar(GraalHotSpotVMConfig config) { final long pollingPageAddress = config.safepointPollingAddress; return config.forceUnreachable || !isInt(pollingPageAddress - config.codeCacheLowBound) || !isInt(pollingPageAddress - config.codeCacheHighBound); } private static void emitGlobalPoll(CompilationResultBuilder crb, AMD64MacroAssembler asm, GraalHotSpotVMConfig config, boolean atReturn, LIRFrameState state, Register scratch) { assert !atReturn || state == null : "state is unneeded at return"; if (ImmutableCode.getValue(crb.getOptions())) { JavaKind hostWordKind = JavaKind.Long; int alignment = hostWordKind.getBitCount() / Byte.SIZE; JavaConstant pollingPageAddress = JavaConstant.forIntegerKind(hostWordKind, config.safepointPollingAddress); // This move will be patched to load the safepoint page from a data segment // co-located with the immutable code. if (GeneratePIC.getValue(crb.getOptions())) { asm.movq(scratch, asm.getPlaceholder(-1)); } else { asm.movq(scratch, (AMD64Address) crb.recordDataReferenceInCode(pollingPageAddress, alignment)); } final int pos = asm.position(); crb.recordMark(atReturn ? HotSpotMarkId.POLL_RETURN_FAR : HotSpotMarkId.POLL_FAR); if (state != null) { crb.recordInfopoint(pos, state, InfopointReason.SAFEPOINT); } asm.testl(rax, new AMD64Address(scratch)); } else if (isPollingPageFar(config)) { asm.movq(scratch, config.safepointPollingAddress); crb.recordMark(atReturn ? HotSpotMarkId.POLL_RETURN_FAR : HotSpotMarkId.POLL_FAR); final int pos = asm.position(); if (state != null) { crb.recordInfopoint(pos, state, InfopointReason.SAFEPOINT); } asm.testl(rax, new AMD64Address(scratch)); } else { crb.recordMark(atReturn ? HotSpotMarkId.POLL_RETURN_NEAR : HotSpotMarkId.POLL_NEAR); final int pos = asm.position(); if (state != null) { crb.recordInfopoint(pos, state, InfopointReason.SAFEPOINT); } // The C++ code transforms the polling page offset into an RIP displacement // to the real address at that offset in the polling page. asm.testl(rax, new AMD64Address(rip, 0)); } } private static void emitThreadLocalPoll(CompilationResultBuilder crb, AMD64MacroAssembler asm, GraalHotSpotVMConfig config, boolean atReturn, LIRFrameState state, Register thread, Register scratch) { assert !atReturn || state == null : "state is unneeded at return"; assert config.threadPollingPageOffset >= 0; asm.movptr(scratch, new AMD64Address(thread, config.threadPollingPageOffset)); crb.recordMark(atReturn ? HotSpotMarkId.POLL_RETURN_FAR : HotSpotMarkId.POLL_FAR); final int pos = asm.position(); if (state != null) { crb.recordInfopoint(pos, state, InfopointReason.SAFEPOINT); } asm.testl(rax, new AMD64Address(scratch)); } }