1 /*
   2  * Copyright (c) 2012, 2016, 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.amd64;
  24 
  25 import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.ILLEGAL;
  26 import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.REG;
  27 
  28 import org.graalvm.compiler.asm.amd64.AMD64MacroAssembler;
  29 import org.graalvm.compiler.hotspot.GraalHotSpotVMConfig;
  30 import org.graalvm.compiler.lir.LIRInstructionClass;
  31 import org.graalvm.compiler.lir.Opcode;
  32 import org.graalvm.compiler.lir.asm.CompilationResultBuilder;
  33 import org.graalvm.compiler.lir.gen.DiagnosticLIRGeneratorTool.ZapStackArgumentSpaceBeforeInstruction;
  34 
  35 import jdk.vm.ci.amd64.AMD64.CPUFeature;
  36 import jdk.vm.ci.code.Register;
  37 import jdk.vm.ci.meta.Value;
  38 
  39 /**
  40  * Returns from a function.
  41  */
  42 @Opcode("RETURN")
  43 final class AMD64HotSpotReturnOp extends AMD64HotSpotEpilogueBlockEndOp implements ZapStackArgumentSpaceBeforeInstruction {
  44 
  45     public static final LIRInstructionClass<AMD64HotSpotReturnOp> TYPE = LIRInstructionClass.create(AMD64HotSpotReturnOp.class);
  46     @Use({REG, ILLEGAL}) protected Value value;
  47     private final boolean isStub;
  48     private final Register scratchForSafepointOnReturn;
  49     private final GraalHotSpotVMConfig config;
  50 
  51     AMD64HotSpotReturnOp(Value value, boolean isStub, Register scratchForSafepointOnReturn, GraalHotSpotVMConfig config) {
  52         super(TYPE);
  53         this.value = value;
  54         this.isStub = isStub;
  55         this.scratchForSafepointOnReturn = scratchForSafepointOnReturn;
  56         this.config = config;
  57     }
  58 
  59     @Override
  60     public void emitCode(CompilationResultBuilder crb, AMD64MacroAssembler masm) {
  61         leaveFrameAndRestoreRbp(crb, masm);
  62         if (!isStub) {
  63             // Every non-stub compile method must have a poll before the return.
  64             AMD64HotSpotSafepointOp.emitCode(crb, masm, config, true, null, scratchForSafepointOnReturn);
  65 
  66             /*
  67              * We potentially return to the interpreter, and that's an AVX-SSE transition. The only
  68              * live value at this point should be the return value in either rax, or in xmm0 with
  69              * the upper half of the register unused, so we don't destroy any value here.
  70              */
  71             if (masm.supports(CPUFeature.AVX)) {
  72                 masm.vzeroupper();
  73             }
  74         }
  75         masm.ret(0);
  76     }
  77 }