1 /*
   2  * Copyright (c) 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.lir.amd64;
  24 
  25 import org.graalvm.compiler.asm.amd64.AMD64MacroAssembler;
  26 import org.graalvm.compiler.lir.LIRInstructionClass;
  27 import org.graalvm.compiler.lir.Opcode;
  28 import org.graalvm.compiler.lir.asm.CompilationResultBuilder;
  29 
  30 import jdk.vm.ci.code.StackSlot;
  31 import jdk.vm.ci.meta.JavaConstant;
  32 
  33 /**
  34  * Writes well known garbage values to stack slots.
  35  */
  36 @Opcode("ZAP_STACK")
  37 public final class AMD64ZapStackOp extends AMD64LIRInstruction {
  38     public static final LIRInstructionClass<AMD64ZapStackOp> TYPE = LIRInstructionClass.create(AMD64ZapStackOp.class);
  39 
  40     /**
  41      * The stack slots that are zapped.
  42      */
  43     @Def(OperandFlag.STACK) protected final StackSlot[] zappedStack;
  44 
  45     /**
  46      * The garbage values that are written to the stack.
  47      */
  48     protected final JavaConstant[] zapValues;
  49 
  50     public AMD64ZapStackOp(StackSlot[] zappedStack, JavaConstant[] zapValues) {
  51         super(TYPE);
  52         this.zappedStack = zappedStack;
  53         this.zapValues = zapValues;
  54     }
  55 
  56     @Override
  57     public void emitCode(CompilationResultBuilder crb, AMD64MacroAssembler masm) {
  58         for (int i = 0; i < zappedStack.length; i++) {
  59             StackSlot slot = zappedStack[i];
  60             if (slot != null) {
  61                 AMD64Move.const2stack(crb, masm, slot, zapValues[i]);
  62             }
  63         }
  64     }
  65 }