| /* |
| * ProGuard -- shrinking, optimization, obfuscation, and preverification |
| * of Java bytecode. |
| * |
| * Copyright (c) 2002-2009 Eric Lafortune (eric@graphics.cornell.edu) |
| * |
| * This program is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License as published by the Free |
| * Software Foundation; either version 2 of the License, or (at your option) |
| * any later version. |
| * |
| * This program 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 for |
| * more details. |
| * |
| * You should have received a copy of the GNU General Public License along |
| * with this program; if not, write to the Free Software Foundation, Inc., |
| * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| */ |
| package proguard.classfile.instruction; |
| |
| import proguard.classfile.*; |
| import proguard.classfile.attribute.CodeAttribute; |
| import proguard.classfile.instruction.visitor.InstructionVisitor; |
| |
| /** |
| * This Instruction represents an instruction that refers to a variable on the |
| * local variable stack. |
| * |
| * @author Eric Lafortune |
| */ |
| public class VariableInstruction extends Instruction |
| { |
| public boolean wide; |
| public int variableIndex; |
| public int constant; |
| |
| |
| /** |
| * Creates an uninitialized VariableInstruction. |
| */ |
| public VariableInstruction() {} |
| |
| |
| public VariableInstruction(boolean wide) |
| { |
| this.wide = wide; |
| } |
| |
| |
| public VariableInstruction(byte opcode) |
| { |
| this(opcode, embeddedVariable(opcode), 0); |
| } |
| |
| |
| public VariableInstruction(byte opcode, |
| int variableIndex) |
| { |
| this(opcode, variableIndex, 0); |
| } |
| |
| |
| public VariableInstruction(byte opcode, |
| int variableIndex, |
| int constant) |
| { |
| this.opcode = opcode; |
| this.variableIndex = variableIndex; |
| this.constant = constant; |
| this.wide = requiredVariableIndexSize() > 1 || |
| requiredConstantSize() > 1; |
| } |
| |
| |
| /** |
| * Copies the given instruction into this instruction. |
| * @param variableInstruction the instruction to be copied. |
| * @return this instruction. |
| */ |
| public VariableInstruction copy(VariableInstruction variableInstruction) |
| { |
| this.opcode = variableInstruction.opcode; |
| this.variableIndex = variableInstruction.variableIndex; |
| this.constant = variableInstruction.constant; |
| this.wide = variableInstruction.wide; |
| |
| return this; |
| } |
| |
| |
| /** |
| * Return the embedded variable of the given opcode, or 0 if the opcode |
| * doesn't have one. |
| */ |
| private static int embeddedVariable(byte opcode) |
| { |
| switch (opcode) |
| { |
| case InstructionConstants.OP_ILOAD_1: |
| case InstructionConstants.OP_LLOAD_1: |
| case InstructionConstants.OP_FLOAD_1: |
| case InstructionConstants.OP_DLOAD_1: |
| case InstructionConstants.OP_ALOAD_1: |
| case InstructionConstants.OP_ISTORE_1: |
| case InstructionConstants.OP_LSTORE_1: |
| case InstructionConstants.OP_FSTORE_1: |
| case InstructionConstants.OP_DSTORE_1: |
| case InstructionConstants.OP_ASTORE_1: return 1; |
| |
| case InstructionConstants.OP_ILOAD_2: |
| case InstructionConstants.OP_LLOAD_2: |
| case InstructionConstants.OP_FLOAD_2: |
| case InstructionConstants.OP_DLOAD_2: |
| case InstructionConstants.OP_ALOAD_2: |
| case InstructionConstants.OP_ISTORE_2: |
| case InstructionConstants.OP_LSTORE_2: |
| case InstructionConstants.OP_FSTORE_2: |
| case InstructionConstants.OP_DSTORE_2: |
| case InstructionConstants.OP_ASTORE_2: return 2; |
| |
| case InstructionConstants.OP_ILOAD_3: |
| case InstructionConstants.OP_LLOAD_3: |
| case InstructionConstants.OP_FLOAD_3: |
| case InstructionConstants.OP_DLOAD_3: |
| case InstructionConstants.OP_ALOAD_3: |
| case InstructionConstants.OP_ISTORE_3: |
| case InstructionConstants.OP_LSTORE_3: |
| case InstructionConstants.OP_FSTORE_3: |
| case InstructionConstants.OP_DSTORE_3: |
| case InstructionConstants.OP_ASTORE_3: return 3; |
| |
| default: return 0; |
| } |
| } |
| |
| |
| /** |
| * Returns whether this instruction stores the value of a variable. |
| * The value is false for the ret instruction, but true for the iinc |
| * instruction. |
| */ |
| public boolean isStore() |
| { |
| // A store instruction can be recognized as follows. Note that this |
| // excludes the ret instruction, which has a negative opcode. |
| return opcode >= InstructionConstants.OP_ISTORE || |
| opcode == InstructionConstants.OP_IINC; |
| } |
| |
| |
| /** |
| * Returns whether this instruction loads the value of a variable. |
| * The value is true for the ret instruction and for the iinc |
| * instruction. |
| */ |
| public boolean isLoad() |
| { |
| // A load instruction can be recognized as follows. Note that this |
| // includes the ret instruction, which has a negative opcode. |
| return opcode < InstructionConstants.OP_ISTORE; |
| } |
| |
| |
| // Implementations for Instruction. |
| |
| public byte canonicalOpcode() |
| { |
| // Remove the _0, _1, _2, _3 extension, if any. |
| switch (opcode) |
| { |
| case InstructionConstants.OP_ILOAD_0: |
| case InstructionConstants.OP_ILOAD_1: |
| case InstructionConstants.OP_ILOAD_2: |
| case InstructionConstants.OP_ILOAD_3: return InstructionConstants.OP_ILOAD; |
| case InstructionConstants.OP_LLOAD_0: |
| case InstructionConstants.OP_LLOAD_1: |
| case InstructionConstants.OP_LLOAD_2: |
| case InstructionConstants.OP_LLOAD_3: return InstructionConstants.OP_LLOAD; |
| case InstructionConstants.OP_FLOAD_0: |
| case InstructionConstants.OP_FLOAD_1: |
| case InstructionConstants.OP_FLOAD_2: |
| case InstructionConstants.OP_FLOAD_3: return InstructionConstants.OP_FLOAD; |
| case InstructionConstants.OP_DLOAD_0: |
| case InstructionConstants.OP_DLOAD_1: |
| case InstructionConstants.OP_DLOAD_2: |
| case InstructionConstants.OP_DLOAD_3: return InstructionConstants.OP_DLOAD; |
| case InstructionConstants.OP_ALOAD_0: |
| case InstructionConstants.OP_ALOAD_1: |
| case InstructionConstants.OP_ALOAD_2: |
| case InstructionConstants.OP_ALOAD_3: return InstructionConstants.OP_ALOAD; |
| |
| case InstructionConstants.OP_ISTORE_0: |
| case InstructionConstants.OP_ISTORE_1: |
| case InstructionConstants.OP_ISTORE_2: |
| case InstructionConstants.OP_ISTORE_3: return InstructionConstants.OP_ISTORE; |
| case InstructionConstants.OP_LSTORE_0: |
| case InstructionConstants.OP_LSTORE_1: |
| case InstructionConstants.OP_LSTORE_2: |
| case InstructionConstants.OP_LSTORE_3: return InstructionConstants.OP_LSTORE; |
| case InstructionConstants.OP_FSTORE_0: |
| case InstructionConstants.OP_FSTORE_1: |
| case InstructionConstants.OP_FSTORE_2: |
| case InstructionConstants.OP_FSTORE_3: return InstructionConstants.OP_FSTORE; |
| case InstructionConstants.OP_DSTORE_0: |
| case InstructionConstants.OP_DSTORE_1: |
| case InstructionConstants.OP_DSTORE_2: |
| case InstructionConstants.OP_DSTORE_3: return InstructionConstants.OP_DSTORE; |
| case InstructionConstants.OP_ASTORE_0: |
| case InstructionConstants.OP_ASTORE_1: |
| case InstructionConstants.OP_ASTORE_2: |
| case InstructionConstants.OP_ASTORE_3: return InstructionConstants.OP_ASTORE; |
| |
| default: return opcode; |
| } |
| } |
| |
| public Instruction shrink() |
| { |
| opcode = canonicalOpcode(); |
| |
| // Is this instruction pointing to a variable with index from 0 to 3? |
| if (variableIndex <= 3) |
| { |
| switch (opcode) |
| { |
| case InstructionConstants.OP_ILOAD: opcode = (byte)(InstructionConstants.OP_ILOAD_0 + variableIndex); break; |
| case InstructionConstants.OP_LLOAD: opcode = (byte)(InstructionConstants.OP_LLOAD_0 + variableIndex); break; |
| case InstructionConstants.OP_FLOAD: opcode = (byte)(InstructionConstants.OP_FLOAD_0 + variableIndex); break; |
| case InstructionConstants.OP_DLOAD: opcode = (byte)(InstructionConstants.OP_DLOAD_0 + variableIndex); break; |
| case InstructionConstants.OP_ALOAD: opcode = (byte)(InstructionConstants.OP_ALOAD_0 + variableIndex); break; |
| |
| case InstructionConstants.OP_ISTORE: opcode = (byte)(InstructionConstants.OP_ISTORE_0 + variableIndex); break; |
| case InstructionConstants.OP_LSTORE: opcode = (byte)(InstructionConstants.OP_LSTORE_0 + variableIndex); break; |
| case InstructionConstants.OP_FSTORE: opcode = (byte)(InstructionConstants.OP_FSTORE_0 + variableIndex); break; |
| case InstructionConstants.OP_DSTORE: opcode = (byte)(InstructionConstants.OP_DSTORE_0 + variableIndex); break; |
| case InstructionConstants.OP_ASTORE: opcode = (byte)(InstructionConstants.OP_ASTORE_0 + variableIndex); break; |
| } |
| } |
| |
| // Only make the instruction wide if necessary. |
| wide = requiredVariableIndexSize() > 1 || |
| requiredConstantSize() > 1; |
| |
| return this; |
| } |
| |
| |
| protected boolean isWide() |
| { |
| return wide; |
| } |
| |
| |
| protected void readInfo(byte[] code, int offset) |
| { |
| int variableIndexSize = variableIndexSize(); |
| int constantSize = constantSize(); |
| |
| // Also initialize embedded variable indexes. |
| if (variableIndexSize == 0) |
| { |
| // An embedded variable index can be decoded as follows. |
| variableIndex = opcode < InstructionConstants.OP_ISTORE_0 ? |
| (opcode - InstructionConstants.OP_ILOAD_0 ) & 3 : |
| (opcode - InstructionConstants.OP_ISTORE_0) & 3; |
| } |
| else |
| { |
| variableIndex = readValue(code, offset, variableIndexSize); offset += variableIndexSize; |
| } |
| |
| constant = readSignedValue(code, offset, constantSize); |
| } |
| |
| |
| protected void writeInfo(byte[] code, int offset) |
| { |
| int variableIndexSize = variableIndexSize(); |
| int constantSize = constantSize(); |
| |
| if (requiredVariableIndexSize() > variableIndexSize) |
| { |
| throw new IllegalArgumentException("Instruction has invalid variable index size ("+this.toString(offset)+")"); |
| } |
| |
| if (requiredConstantSize() > constantSize) |
| { |
| throw new IllegalArgumentException("Instruction has invalid constant size ("+this.toString(offset)+")"); |
| } |
| |
| writeValue(code, offset, variableIndex, variableIndexSize); offset += variableIndexSize; |
| writeSignedValue(code, offset, constant, constantSize); |
| } |
| |
| |
| public int length(int offset) |
| { |
| return (wide ? 2 : 1) + variableIndexSize() + constantSize(); |
| } |
| |
| |
| public void accept(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, InstructionVisitor instructionVisitor) |
| { |
| instructionVisitor.visitVariableInstruction(clazz, method, codeAttribute, offset, this); |
| } |
| |
| |
| // Implementations for Object. |
| |
| public String toString() |
| { |
| return getName() + |
| (wide ? "_w" : "") + |
| " v"+variableIndex + |
| (constantSize() > 0 ? ", "+constant : ""); |
| } |
| |
| |
| // Small utility methods. |
| |
| /** |
| * Returns the variable index size for this instruction. |
| */ |
| private int variableIndexSize() |
| { |
| return (opcode >= InstructionConstants.OP_ILOAD_0 && |
| opcode <= InstructionConstants.OP_ALOAD_3) || |
| (opcode >= InstructionConstants.OP_ISTORE_0 && |
| opcode <= InstructionConstants.OP_ASTORE_3) ? 0 : |
| wide ? 2 : |
| 1; |
| } |
| |
| |
| /** |
| * Computes the required variable index size for this instruction's variable |
| * index. |
| */ |
| private int requiredVariableIndexSize() |
| { |
| return (variableIndex & 0x3) == variableIndex ? 0 : |
| (variableIndex & 0xff) == variableIndex ? 1 : |
| (variableIndex & 0xffff) == variableIndex ? 2 : |
| 4; |
| |
| } |
| |
| |
| /** |
| * Returns the constant size for this instruction. |
| */ |
| private int constantSize() |
| { |
| return opcode != InstructionConstants.OP_IINC ? 0 : |
| wide ? 2 : |
| 1; |
| } |
| |
| |
| /** |
| * Computes the required constant size for this instruction's constant. |
| */ |
| private int requiredConstantSize() |
| { |
| return opcode != InstructionConstants.OP_IINC ? 0 : |
| constant << 24 >> 24 == constant ? 1 : |
| constant << 16 >> 16 == constant ? 2 : |
| 4; |
| } |
| } |
