1 /*
   2  * Copyright (c) 2013, 2015, 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 package org.graalvm.compiler.hotspot.aarch64;
  24 
  25 import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.ILLEGAL;
  26 import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.REG;
  27 import static jdk.vm.ci.aarch64.AArch64.lr;
  28 import static jdk.vm.ci.code.ValueUtil.asRegister;
  29 
  30 import org.graalvm.compiler.asm.aarch64.AArch64MacroAssembler;
  31 import org.graalvm.compiler.hotspot.GraalHotSpotVMConfig;
  32 import org.graalvm.compiler.lir.LIRInstructionClass;
  33 import org.graalvm.compiler.lir.Opcode;
  34 import org.graalvm.compiler.lir.asm.CompilationResultBuilder;
  35 
  36 import jdk.vm.ci.meta.Value;
  37 
  38 /**
  39  * Returns from a function.
  40  */
  41 @Opcode("RETURN")
  42 public final class AArch64HotSpotReturnOp extends AArch64HotSpotEpilogueOp {
  43 
  44     public static final LIRInstructionClass<AArch64HotSpotReturnOp> TYPE = LIRInstructionClass.create(AArch64HotSpotReturnOp.class);
  45 
  46     @Use({REG, ILLEGAL}) private Value result;
  47     private final boolean isStub;
  48 
  49     public AArch64HotSpotReturnOp(Value result, boolean isStub, GraalHotSpotVMConfig config) {
  50         super(TYPE, config);
  51         assert validReturnValue(result);
  52         this.result = result;
  53         this.isStub = isStub;
  54     }
  55 
  56     private static boolean validReturnValue(Value result) {
  57         if (result.equals(Value.ILLEGAL)) {
  58             return true;
  59         }
  60         return asRegister(result).encoding == 0;
  61     }
  62 
  63     @Override
  64     public void emitCode(CompilationResultBuilder crb, AArch64MacroAssembler masm) {
  65         final boolean emitSafepoint = !isStub;
  66         leaveFrame(crb, masm, emitSafepoint);
  67         masm.ret(lr);
  68     }
  69 }