1 /* 2 * Copyright (c) 2001, 2011, 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. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package jdk.internal.reflect; 27 28 import java.util.List; 29 import java.util.ArrayList; 30 31 /** Allows forward references in bytecode streams emitted by 32 ClassFileAssembler. Assumes that the start of the method body is 33 the first byte in the assembler's buffer. May be used at more than 34 one branch site. */ 35 36 class Label { 37 static class PatchInfo { PatchInfo(ClassFileAssembler asm, short instrBCI, short patchBCI, int stackDepth)38 PatchInfo(ClassFileAssembler asm, 39 short instrBCI, 40 short patchBCI, 41 int stackDepth) 42 { 43 this.asm = asm; 44 this.instrBCI = instrBCI; 45 this.patchBCI = patchBCI; 46 this.stackDepth = stackDepth; 47 } 48 // This won't work for more than one assembler anyway, so this is 49 // unnecessary 50 final ClassFileAssembler asm; 51 final short instrBCI; 52 final short patchBCI; 53 final int stackDepth; 54 } 55 private final List<PatchInfo> patches = new ArrayList<>(); 56 Label()57 public Label() { 58 } 59 add(ClassFileAssembler asm, short instrBCI, short patchBCI, int stackDepth)60 void add(ClassFileAssembler asm, 61 short instrBCI, 62 short patchBCI, 63 int stackDepth) 64 { 65 patches.add(new PatchInfo(asm, instrBCI, patchBCI, stackDepth)); 66 } 67 bind()68 public void bind() { 69 for (PatchInfo patch : patches){ 70 short curBCI = patch.asm.getLength(); 71 short offset = (short) (curBCI - patch.instrBCI); 72 patch.asm.emitShort(patch.patchBCI, offset); 73 patch.asm.setStack(patch.stackDepth); 74 } 75 } 76 } 77