Mercurial > hg > graal-jvmci-8
view agent/src/share/classes/sun/jvm/hotspot/oops/MultiBranchData.java @ 4737:75c0a73eee98
7102776: Pack instanceKlass boolean fields into single u1 field
Summary: Reduce class runtime memory usage by packing 4 instanceKlass boolean fields into single u1 field. Save 4-byte for each loaded class.
Reviewed-by: dholmes, bobv, phh, twisti, never, coleenp
Contributed-by: Jiangli Zhou <jiangli.zhou@oracle.com>
author | coleenp |
---|---|
date | Thu, 17 Nov 2011 12:53:59 -0500 |
parents | f6f3bb0ee072 |
children | 4bec1b1f7b33 |
line wrap: on
line source
/* * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved. * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. * * * * * * * * * * * * * * * * * * * */ package sun.jvm.hotspot.oops; import java.io.*; import java.util.*; import sun.jvm.hotspot.debugger.*; import sun.jvm.hotspot.runtime.*; import sun.jvm.hotspot.types.*; import sun.jvm.hotspot.utilities.*; // MultiBranchData // // A MultiBranchData is used to access profiling information for // a multi-way branch (*switch bytecodes). It consists of a series // of (count, displacement) pairs, which count the number of times each // case was taken and specify the data displacment for each branch target. public class MultiBranchData extends ArrayData { static final int defaultCountOffSet = 0; static final int defaultDisaplacementOffSet = 1; static final int caseArrayStart = 2; static final int relativeCountOffSet = 0; static final int relativeDisplacementOffSet = 1; static final int perCaseCellCount = 2; public MultiBranchData(DataLayout layout) { super(layout); //assert(layout.tag() == DataLayout.multiBranchDataTag, "wrong type"); } // static int computeCellCount(BytecodeStream stream); int numberOfCases() { int alen = arrayLen() - 2; // get rid of default case here. //assert(alen % perCaseCellCount == 0, "must be even"); return (alen / perCaseCellCount); } int defaultCount() { return arrayUintAt(defaultCountOffSet); } int defaultDisplacement() { return arrayIntAt(defaultDisaplacementOffSet); } int countAt(int index) { return arrayUintAt(caseArrayStart + index * perCaseCellCount + relativeCountOffSet); } int displacementAt(int index) { return arrayIntAt(caseArrayStart + index * perCaseCellCount + relativeDisplacementOffSet); } // Code generation support static int defaultCountOffset() { return arrayElementOffset(defaultCountOffSet); } static int defaultDisplacementOffset() { return arrayElementOffset(defaultDisaplacementOffSet); } static int caseCountOffset(int index) { return caseArrayOffset() + (perCaseSize() * index) + relativeCountOffset(); } static int caseArrayOffset() { return arrayElementOffset(caseArrayStart); } static int perCaseSize() { return (perCaseCellCount) * MethodData.cellSize; } static int relativeCountOffset() { return (relativeCountOffSet) * MethodData.cellSize; } static int relativeDisplacementOffset() { return (relativeDisplacementOffSet) * MethodData.cellSize; } public void printDataOn(PrintStream st) { printShared(st, "MultiBranchData"); st.println("default_count(" + defaultCount() + ") displacement(" + defaultDisplacement() + ")"); int cases = numberOfCases(); for (int i = 0; i < cases; i++) { tab(st); st.println("count(" + countAt(i) + ") displacement(" + displacementAt(i) + ")"); } } }