jdk8-mips64-public/langtools: src/share/classes/com/sun/tools/classfile/Instruction.java@2eb010b6cb22 (annotated)

src/share/classes/com/sun/tools/classfile/Instruction.java@2eb010b6cb22 (annotated)

src/share/classes/com/sun/tools/classfile/Instruction.java

Thu, 31 Aug 2017 15:17:03 +0800

author: aoqi
date: Thu, 31 Aug 2017 15:17:03 +0800
changeset 2525: 2eb010b6cb22
parent 2413: fe033d997ddf
parent 0: 959103a6100f
permissions: -rw-r--r--

merge

 /*
  * Copyright (c) 2009, 2013, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this
  * particular file as subject to the "Classpath" exception as provided
  * by Oracle in the LICENSE file that accompanied this code.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */
 package com.sun.tools.classfile;
 import java.util.Locale;
 /**
  * See JVMS, chapter 6.
  *
  *  <p><b>This is NOT part of any supported API.
  *  If you write code that depends on this, you do so at your own risk.
  *  This code and its internal interfaces are subject to change or
  *  deletion without notice.</b>
  *
  * @see Code_attribute#getInstructions
  */
 public class Instruction {
     /** The kind of an instruction, as determined by the position, size and
      *  types of its operands. */
     public static enum Kind {
         /** Opcode is not followed by any operands. */
         NO_OPERANDS(1),
         /** Opcode is followed by a byte indicating a type. */
         ATYPE(2),
         /** Opcode is followed by a 2-byte branch offset. */
         BRANCH(3),
         /** Opcode is followed by a 4-byte branch offset. */
         BRANCH_W(5),
         /** Opcode is followed by a signed byte value. */
         BYTE(2),
         /** Opcode is followed by a 1-byte index into the constant pool. */
         CPREF(2),
         /** Opcode is followed by a 2-byte index into the constant pool. */
         CPREF_W(3),
         /** Opcode is followed by a 2-byte index into the constant pool,
          *  an unsigned byte value. */
         CPREF_W_UBYTE(4),
         /** Opcode is followed by a 2-byte index into the constant pool.,
          *  an unsigned byte value, and a zero byte. */
         CPREF_W_UBYTE_ZERO(5),
         /** Opcode is followed by variable number of operands, depending
          * on the instruction.*/
         DYNAMIC(-1),
         /** Opcode is followed by a 1-byte reference to a local variable. */
         LOCAL(2),
         /** Opcode is followed by a 1-byte reference to a local variable,
          *  and a signed byte value. */
         LOCAL_BYTE(3),
         /** Opcode is followed by a signed short value. */
         SHORT(3),
         /** Wide opcode is not followed by any operands. */
         WIDE_NO_OPERANDS(2),
         /** Wide opcode is followed by a 2-byte index into the local variables array. */
         WIDE_LOCAL(4),
         /** Wide opcode is followed by a 2-byte index into the constant pool. */
         WIDE_CPREF_W(4),
         /** Wide opcode is followed by a 2-byte index into the constant pool,
          *  and a signed short value. */
         WIDE_CPREF_W_SHORT(6),
         /** Wide opcode is followed by a 2-byte reference to a local variable,
          *  and a signed short value. */
         WIDE_LOCAL_SHORT(6),
         /** Opcode was not recognized. */
         UNKNOWN(1);
         Kind(int length) {
             this.length = length;
         }
         /** The length, in bytes, of this kind of instruction, or -1 is the
          *  length depends on the specific instruction. */
         public final int length;
     };
     /** A utility visitor to help decode the operands of an instruction.
      *  @see Instruction#accept */
     public interface KindVisitor<R,P> {
         /** See {@link Kind#NO_OPERANDS}, {@link Kind#WIDE_NO_OPERANDS}. */
         R visitNoOperands(Instruction instr, P p);
         /** See {@link Kind#ATYPE}. */
         R visitArrayType(Instruction instr, TypeKind kind, P p);
         /** See {@link Kind#BRANCH}, {@link Kind#BRANCH_W}. */
         R visitBranch(Instruction instr, int offset, P p);
         /** See {@link Kind#CPREF}, {@link Kind#CPREF_W}, {@link Kind#WIDE_CPREF_W}. */
         R visitConstantPoolRef(Instruction instr, int index, P p);
         /** See {@link Kind#CPREF_W_UBYTE}, {@link Kind#CPREF_W_UBYTE_ZERO}, {@link Kind#WIDE_CPREF_W_SHORT}. */
         R visitConstantPoolRefAndValue(Instruction instr, int index, int value, P p);
         /** See {@link Kind#LOCAL}, {@link Kind#WIDE_LOCAL}. */
         R visitLocal(Instruction instr, int index, P p);
         /** See {@link Kind#LOCAL_BYTE}. */
         R visitLocalAndValue(Instruction instr, int index, int value, P p);
         /** See {@link Kind#DYNAMIC}. */
         R visitLookupSwitch(Instruction instr, int default_, int npairs, int[] matches, int[] offsets, P p);
         /** See {@link Kind#DYNAMIC}. */
         R visitTableSwitch(Instruction instr, int default_, int low, int high, int[] offsets, P p);
         /** See {@link Kind#BYTE}, {@link Kind#SHORT}. */
         R visitValue(Instruction instr, int value, P p);
         /** Instruction is unrecognized. */
         R visitUnknown(Instruction instr, P p);
     }
     /** The kind of primitive array type to create.
      *  See JVMS chapter 6, newarray. */
     public static enum TypeKind {
         T_BOOLEAN(4, "boolean"),
         T_CHAR(5, "char"),
         T_FLOAT(6, "float"),
         T_DOUBLE(7, "double"),
         T_BYTE(8, "byte"),
         T_SHORT(9, "short"),
         T_INT (10, "int"),
         T_LONG (11, "long");
         TypeKind(int value, String name) {
             this.value = value;
             this.name = name;
         }
         public static TypeKind get(int value) {
             switch (value) {
                 case  4: return T_BOOLEAN;
                 case  5: return T_CHAR;
                 case  6: return T_FLOAT;
                 case  7: return T_DOUBLE;
                 case  8: return T_BYTE;
                 case  9: return T_SHORT;
                 case  10: return T_INT;
                 case  11: return T_LONG;
                 default: return null;
             }
         }
         public final int value;
         public final String name;
     }
     /** An instruction is defined by its position in a bytecode array. */
     public Instruction(byte[] bytes, int pc) {
         this.bytes = bytes;
         this.pc = pc;
     }
     /** Get the position of the instruction within the bytecode array. */
     public int getPC() {
         return pc;
     }
     /** Get a byte value, relative to the start of this instruction. */
     public int getByte(int offset) {
         return bytes[pc + offset];
     }
     /** Get an unsigned byte value, relative to the start of this instruction. */
     public int getUnsignedByte(int offset) {
         return getByte(offset) & 0xff;
     }
     /** Get a 2-byte value, relative to the start of this instruction. */
     public int getShort(int offset) {
         return (getByte(offset) << 8) | getUnsignedByte(offset + 1);
     }
     /** Get a unsigned 2-byte value, relative to the start of this instruction. */
     public int getUnsignedShort(int offset) {
         return getShort(offset) & 0xFFFF;
     }
     /** Get a 4-byte value, relative to the start of this instruction. */
     public int getInt(int offset) {
         return (getShort(offset) << 16) | (getUnsignedShort(offset + 2));
     }
     /** Get the Opcode for this instruction, or null if the instruction is
      * unrecognized. */
     public Opcode getOpcode() {
         int b = getUnsignedByte(0);
         switch (b) {
             case Opcode.NONPRIV:
             case Opcode.PRIV:
             case Opcode.WIDE:
                 return Opcode.get(b, getUnsignedByte(1));
         }
         return Opcode.get(b);
     }
     /** Get the mnemonic for this instruction, or a default string if the
      * instruction is unrecognized. */
     public String getMnemonic() {
         Opcode opcode = getOpcode();
         if (opcode == null)
             return "bytecode " + getUnsignedByte(0);
         else
             return opcode.toString().toLowerCase(Locale.US);
     }
     /** Get the length, in bytes, of this instruction, including the opcode
      * and all its operands. */
     public int length() {
         Opcode opcode = getOpcode();
         if (opcode == null)
             return 1;
         switch (opcode) {
             case TABLESWITCH: {
                 int pad = align(pc + 1) - pc;
                 int low = getInt(pad + 4);
                 int high = getInt(pad + 8);
                 return pad + 12 + 4 * (high - low + 1);
             }
             case LOOKUPSWITCH: {
                 int pad = align(pc + 1) - pc;
                 int npairs = getInt(pad + 4);
                 return pad + 8 + 8 * npairs;
             }
             default:
                 return opcode.kind.length;
         }
     }
     /** Get the {@link Kind} of this instruction. */
     public Kind getKind() {
         Opcode opcode = getOpcode();
         return (opcode != null ? opcode.kind : Kind.UNKNOWN);
     }
     /** Invoke a method on the visitor according to the kind of this
      * instruction, passing in the decoded operands for the instruction. */
     public <R,P> R accept(KindVisitor<R,P> visitor, P p) {
         switch (getKind()) {
             case NO_OPERANDS:
                 return visitor.visitNoOperands(this, p);
             case ATYPE:
                 return visitor.visitArrayType(
                         this, TypeKind.get(getUnsignedByte(1)), p);
             case BRANCH:
                 return visitor.visitBranch(this, getShort(1), p);
             case BRANCH_W:
                 return visitor.visitBranch(this, getInt(1), p);
             case BYTE:
                 return visitor.visitValue(this, getByte(1), p);
             case CPREF:
                 return visitor.visitConstantPoolRef(this, getUnsignedByte(1), p);
             case CPREF_W:
                 return visitor.visitConstantPoolRef(this, getUnsignedShort(1), p);
             case CPREF_W_UBYTE:
             case CPREF_W_UBYTE_ZERO:
                 return visitor.visitConstantPoolRefAndValue(
                         this, getUnsignedShort(1), getUnsignedByte(3), p);
             case DYNAMIC: {
                 switch (getOpcode()) {
                     case TABLESWITCH: {
                         int pad = align(pc + 1) - pc;
                         int default_ = getInt(pad);
                         int low = getInt(pad + 4);
                         int high = getInt(pad + 8);
                         int[] values = new int[high - low + 1];
                         for (int i = 0; i < values.length; i++)
                             values[i] = getInt(pad + 12 + 4 * i);
                         return visitor.visitTableSwitch(
                                 this, default_, low, high, values, p);
                     }
                     case LOOKUPSWITCH: {
                         int pad = align(pc + 1) - pc;
                         int default_ = getInt(pad);
                         int npairs = getInt(pad + 4);
                         int[] matches = new int[npairs];
                         int[] offsets = new int[npairs];
                         for (int i = 0; i < npairs; i++) {
                             matches[i] = getInt(pad +  8 + i * 8);
                             offsets[i] = getInt(pad + 12 + i * 8);
                         }
                         return visitor.visitLookupSwitch(
                                 this, default_, npairs, matches, offsets, p);
                     }
                     default:
                         throw new IllegalStateException();
                 }
             }
             case LOCAL:
                 return visitor.visitLocal(this, getUnsignedByte(1), p);
             case LOCAL_BYTE:
                 return visitor.visitLocalAndValue(
                         this, getUnsignedByte(1), getByte(2), p);
             case SHORT:
                 return visitor.visitValue(this, getShort(1), p);
             case WIDE_NO_OPERANDS:
                 return visitor.visitNoOperands(this, p);
             case WIDE_LOCAL:
                 return visitor.visitLocal(this, getUnsignedShort(2), p);
             case WIDE_CPREF_W:
                 return visitor.visitConstantPoolRef(this, getUnsignedShort(2), p);
             case WIDE_CPREF_W_SHORT:
                 return visitor.visitConstantPoolRefAndValue(
                         this, getUnsignedShort(2), getUnsignedByte(4), p);
             case WIDE_LOCAL_SHORT:
                 return visitor.visitLocalAndValue(
                         this, getUnsignedShort(2), getShort(4), p);
             case UNKNOWN:
                 return visitor.visitUnknown(this, p);
             default:
                 throw new IllegalStateException();
         }
     }
     private static int align(int n) {
         return (n + 3) & ~3;
     }
     private byte[] bytes;
     private int pc;
 }

Mercurial > jdk8-mips64-public > langtools / annotate

src/share/classes/com/sun/tools/classfile/Instruction.java@2eb010b6cb22 (annotated)

src/share/classes/com/sun/tools/classfile/Instruction.java