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 *

 * This code is free software; you can redistribute it and/or modify it

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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.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package org.graalvm.compiler.hotspot.amd64;

import static jdk.vm.ci.amd64.AMD64.r15;

import static jdk.vm.ci.amd64.AMD64.rsp;

import static org.graalvm.compiler.hotspot.HotSpotHostBackend.ENABLE_STACK_RESERVED_ZONE;

import static org.graalvm.compiler.hotspot.HotSpotHostBackend.THROW_DELAYED_STACKOVERFLOW_ERROR;

import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.ILLEGAL;

import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.REG;

import org.graalvm.compiler.asm.Label;

import org.graalvm.compiler.asm.amd64.AMD64Address;

import org.graalvm.compiler.asm.amd64.AMD64Assembler;

import org.graalvm.compiler.asm.amd64.AMD64MacroAssembler;

import org.graalvm.compiler.core.common.spi.ForeignCallLinkage;

import org.graalvm.compiler.hotspot.GraalHotSpotVMConfig;

import org.graalvm.compiler.hotspot.meta.HotSpotForeignCallsProvider;

import org.graalvm.compiler.lir.LIRInstructionClass;

import org.graalvm.compiler.lir.Opcode;

import org.graalvm.compiler.lir.amd64.AMD64Call;

import org.graalvm.compiler.lir.asm.CompilationResultBuilder;

import org.graalvm.compiler.lir.gen.DiagnosticLIRGeneratorTool.ZapStackArgumentSpaceBeforeInstruction;

import jdk.vm.ci.amd64.AMD64.CPUFeature;

import jdk.vm.ci.code.CallingConvention;

import jdk.vm.ci.code.Register;

import jdk.vm.ci.code.RegisterValue;

import jdk.vm.ci.meta.Value;

/**

 * Returns from a function.

 */

@Opcode("RETURN")

final class AMD64HotSpotReturnOp extends AMD64HotSpotEpilogueBlockEndOp implements ZapStackArgumentSpaceBeforeInstruction {

    public static final LIRInstructionClass<AMD64HotSpotReturnOp> TYPE = LIRInstructionClass.create(AMD64HotSpotReturnOp.class);

    @Use({REG, ILLEGAL}) protected Value value;

    private final boolean isStub;

    private final Register thread;

    private final Register scratchForSafepointOnReturn;

    private final GraalHotSpotVMConfig config;

    private final boolean requiresReservedStackAccessCheck;

    AMD64HotSpotReturnOp(Value value, boolean isStub, Register thread, Register scratchForSafepointOnReturn, GraalHotSpotVMConfig config, boolean requiresReservedStackAccessCheck) {

        super(TYPE);

        this.value = value;

        this.isStub = isStub;

        this.thread = thread;

        this.scratchForSafepointOnReturn = scratchForSafepointOnReturn;

        this.config = config;

        this.requiresReservedStackAccessCheck = requiresReservedStackAccessCheck;

    }

    @Override

    public void emitCode(CompilationResultBuilder crb, AMD64MacroAssembler masm) {

        leaveFrameAndRestoreRbp(crb, masm);

        if (!isStub) {

            if (requiresReservedStackAccessCheck) {

                assert scratchForSafepointOnReturn != null;

                HotSpotForeignCallsProvider foreignCalls = (HotSpotForeignCallsProvider) crb.foreignCalls;

                Label noReserved = new Label();

                masm.cmpptr(rsp, new AMD64Address(r15, config.javaThreadReservedStackActivationOffset));

                masm.jccb(AMD64Assembler.ConditionFlag.Below, noReserved);

                // direct call to runtime without stub needs aligned stack

                int stackAdjust = crb.target.stackAlignment - crb.target.wordSize;

                if (stackAdjust > 0) {

                    masm.subq(rsp, stackAdjust);

                }

                ForeignCallLinkage enableStackReservedZone = foreignCalls.lookupForeignCall(ENABLE_STACK_RESERVED_ZONE);

                CallingConvention cc = enableStackReservedZone.getOutgoingCallingConvention();

                assert cc.getArgumentCount() == 1;

                Register arg0 = ((RegisterValue) cc.getArgument(0)).getRegister();

                masm.movq(arg0, thread);

                AMD64Call.directCall(crb, masm, enableStackReservedZone, scratchForSafepointOnReturn, false, null);

                if (stackAdjust > 0) {

                    masm.addq(rsp, stackAdjust);

                }

                AMD64Call.directJmp(crb, masm, foreignCalls.lookupForeignCall(THROW_DELAYED_STACKOVERFLOW_ERROR), scratchForSafepointOnReturn);

                masm.bind(noReserved);

            }

            // Every non-stub compile method must have a poll before the return.

            AMD64HotSpotSafepointOp.emitCode(crb, masm, config, true, null, thread, scratchForSafepointOnReturn);

            /*

             * We potentially return to the interpreter, and that's an AVX-SSE transition. The only

             * live value at this point should be the return value in either rax, or in xmm0 with

             * the upper half of the register unused, so we don't destroy any value here.

             */

                masm.vzeroupper();

            }

        }

        masm.ret(0);

    }

}