1 /*
   2  * Copyright (c) 2009, 2012, 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.sparc;
  24 
  25 import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.REG;
  26 import static jdk.vm.ci.code.ValueUtil.asRegister;
  27 
  28 import org.graalvm.compiler.asm.sparc.SPARCAssembler;
  29 import org.graalvm.compiler.asm.sparc.SPARCMacroAssembler;
  30 import org.graalvm.compiler.lir.LIR;
  31 import org.graalvm.compiler.lir.LIRInstructionClass;
  32 import org.graalvm.compiler.lir.StandardOp.NoOp;
  33 import org.graalvm.compiler.lir.Variable;
  34 import org.graalvm.compiler.lir.asm.CompilationResultBuilder;
  35 
  36 import jdk.vm.ci.code.Register;
  37 import jdk.vm.ci.meta.AllocatableValue;
  38 
  39 /**
  40  * Loads the constant section base into a register.
  41  *
  42  * <p>
  43  * Layout:
  44  *
  45  * <pre>
  46  * +----constant section----+--pad--+---code section--+
  47  * |<-------------------_------------------->|
  48  *                      ^- Constant section base pointer
  49  * </pre>
  50  *
  51  * The constant section base pointer is placed as such that the lowest offset -4096 points to the
  52  * start of the constant section.
  53  * <p>
  54  * If the constant section grows beyond 8k size, the immediate addressing cannot be used anymore; in
  55  * this case absolute addressing (without using the base pointer is used). See also:
  56  * CodeInstaller::pd_patch_DataSectionReference
  57  *
  58  * @see SPARCMove#loadFromConstantTable(CompilationResultBuilder, SPARCMacroAssembler, int,
  59  *      Register, jdk.vm.ci.meta.Constant, Register, SPARCDelayedControlTransfer)
  60  */
  61 public class SPARCLoadConstantTableBaseOp extends SPARCLIRInstruction {
  62     public static final LIRInstructionClass<SPARCLoadConstantTableBaseOp> TYPE = LIRInstructionClass.create(SPARCLoadConstantTableBaseOp.class);
  63     public static final SizeEstimate SIZE = SizeEstimate.create(9);
  64 
  65     private final NoOp placeHolder;
  66     @Def({REG}) private AllocatableValue base;
  67 
  68     public SPARCLoadConstantTableBaseOp(Variable base, NoOp placeHolder) {
  69         super(TYPE, SIZE);
  70         this.base = base;
  71         this.placeHolder = placeHolder;
  72     }
  73 
  74     @Override
  75     public void emitCode(CompilationResultBuilder crb, SPARCMacroAssembler masm) {
  76         Register baseRegister = asRegister(base);
  77         int beforePosition = masm.position();
  78         masm.rdpc(baseRegister);
  79         // Must match with CodeInstaller::pd_patch_DataSectionReference
  80         masm.add(baseRegister, (int) SPARCAssembler.minSimm(13), baseRegister);
  81         masm.sub(baseRegister, beforePosition, baseRegister);
  82     }
  83 
  84     public AllocatableValue getResult() {
  85         return base;
  86     }
  87 
  88     public void setAlive(LIR lir, boolean alive) {
  89         if (alive) {
  90             placeHolder.replace(lir, this);
  91         } else {
  92             placeHolder.remove(lir);
  93         }
  94     }
  95 }