1 /*
   2  * Copyright (c) 2013, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 
  25 package org.graalvm.compiler.hotspot.aarch64;
  26 
  27 import static jdk.vm.ci.aarch64.AArch64.lr;
  28 import static jdk.vm.ci.code.ValueUtil.asRegister;
  29 import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.ILLEGAL;
  30 import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.REG;
  31 
  32 import org.graalvm.compiler.asm.aarch64.AArch64MacroAssembler;
  33 import org.graalvm.compiler.hotspot.GraalHotSpotVMConfig;
  34 import org.graalvm.compiler.lir.LIRInstructionClass;
  35 import org.graalvm.compiler.lir.Opcode;
  36 import org.graalvm.compiler.lir.asm.CompilationResultBuilder;
  37 
  38 import jdk.vm.ci.code.Register;
  39 import jdk.vm.ci.meta.Value;
  40 
  41 /**
  42  * Returns from a function.
  43  */
  44 @Opcode("RETURN")
  45 public final class AArch64HotSpotReturnOp extends AArch64HotSpotEpilogueOp {
  46 
  47     public static final LIRInstructionClass<AArch64HotSpotReturnOp> TYPE = LIRInstructionClass.create(AArch64HotSpotReturnOp.class);
  48 
  49     @Use({REG, ILLEGAL}) private Value result;
  50     private final boolean isStub;
  51     private final boolean requiresReservedStackAccessCheck;
  52 
  53     public AArch64HotSpotReturnOp(Value result, boolean isStub, GraalHotSpotVMConfig config, Register thread, boolean requiresReservedStackAccessCheck) {
  54         super(TYPE, config, thread);
  55         this.requiresReservedStackAccessCheck = requiresReservedStackAccessCheck;
  56         assert validReturnValue(result);
  57         this.result = result;
  58         this.isStub = isStub;
  59     }
  60 
  61     private static boolean validReturnValue(Value result) {
  62         if (result.equals(Value.ILLEGAL)) {
  63             return true;
  64         }
  65         return asRegister(result).encoding == 0;
  66     }
  67 
  68     @Override
  69     public void emitCode(CompilationResultBuilder crb, AArch64MacroAssembler masm) {
  70         final boolean emitSafepoint = !isStub;
  71         leaveFrame(crb, masm, emitSafepoint, requiresReservedStackAccessCheck);
  72         masm.ret(lr);
  73     }
  74 }