--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/src/share/classes/com/sun/tools/classfile/Instruction.java Mon Mar 30 15:08:09 2009 -0700
@@ -0,0 +1,339 @@
+/*
+ * Copyright 2009 Sun Microsystems, Inc. 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. Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package com.sun.tools.classfile;
+
+/**
+ * See JVMS3, chapter 6.
+ *
+ * <p><b>This is NOT part of any API supported by Sun Microsystems. 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 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),
+ /** 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}. */
+ R visitLocal(Instruction instr, int index, P p);
+ /** See {@link Kind#LOCAL_UBYTE}. */
+ 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);
+ /** See {@link Kind#DYNAMIC}. */
+ R visitTableSwitch(Instruction instr, int default_, int low, int high, int[] offsets);
+ /** 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();
+ }
+
+ /** 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);
+ }
+ 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);
+ }
+ 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_CPREF_W:
+ return visitor.visitConstantPoolRef(this, getUnsignedShort(2), p);
+
+ case WIDE_CPREF_W_SHORT:
+ return visitor.visitConstantPoolRefAndValue(
+ this, getUnsignedShort(2), getUnsignedByte(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;
+}