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- /* ====================================================================
- * The Apache Software License, Version 1.1
- *
- * Copyright (c) 2001 The Apache Software Foundation. All rights
- * reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in
- * the documentation and/or other materials provided with the
- * distribution.
- *
- * 3. The end-user documentation included with the redistribution,
- * if any, must include the following acknowledgment:
- * "This product includes software developed by the
- * Apache Software Foundation (https://www.apache.org/)."
- * Alternately, this acknowledgment may appear in the software itself,
- * if and wherever such third-party acknowledgments normally appear.
- *
- * 4. The names "Apache" and "Apache Software Foundation" and
- * "Apache BCEL" must not be used to endorse or promote products
- * derived from this software without prior written permission. For
- * written permission, please contact apache@apache.org.
- *
- * 5. Products derived from this software may not be called "Apache",
- * "Apache BCEL", nor may "Apache" appear in their name, without
- * prior written permission of the Apache Software Foundation.
- *
- * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
- * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
- * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
- * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
- * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- * ====================================================================
- *
- * This software consists of voluntary contributions made by many
- * individuals on behalf of the Apache Software Foundation. For more
- * information on the Apache Software Foundation, please see
- * <https://www.apache.org/>.
- */
- package org.aspectj.apache.bcel.generic;
-
- import java.io.DataOutputStream;
- import java.io.IOException;
-
- import org.aspectj.apache.bcel.Constants;
- import org.aspectj.apache.bcel.classfile.ConstantPool;
-
- /**
- * Abstract super class for branching instructions like GOTO, IFEQ, etc.. Branch instructions may have a variable length, namely
- * GOTO, JSR, LOOKUPSWITCH and TABLESWITCH. A branch instruction may be talking in terms of absolute destination (targetIndex) or
- * about an instruction it doesnt yet know the position if (targetInstruction). targetInstruction (if set) overrides targetIndex
- *
- * @see InstructionList
- * @version $Id: InstructionBranch.java,v 1.6 2009/10/05 17:35:36 aclement Exp $
- * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
- */
- public class InstructionBranch extends Instruction implements InstructionTargeter {
- private static final int UNSET = -1;
-
- protected int targetIndex = UNSET; // Branch target relative to this
- // instruction
- protected InstructionHandle targetInstruction; // Target object in
- // instruction list
- protected int positionOfThisInstruction; // for calculating relative branch
-
- // destinations!
-
- public InstructionBranch(short opcode, InstructionHandle target) {
- super(opcode);
- setTarget(target);
- }
-
- public InstructionBranch(short opcode, int index) {
- super(opcode);
- this.targetIndex = index;
- }
-
- public InstructionBranch(short opcode) {
- super(opcode);
- }
-
- public void dump(DataOutputStream out) throws IOException {
- int target = getTargetOffset();
-
- if (Math.abs(target) >= 32767 && opcode != GOTO_W && opcode != JSR_W) {
- throw new ClassGenException("Branch target offset too large for short. Instruction: " + getName().toUpperCase() + "("
- + opcode + ")");
- }
-
- out.writeByte(opcode);
-
- switch (opcode) {
-
- case GOTO_W:
- case JSR_W:
- out.writeInt(target);
- break;
-
- case IF_ACMPEQ:
- case IF_ACMPNE:
- case IF_ICMPEQ:
- case IF_ICMPGE:
- case IF_ICMPGT:
- case IF_ICMPLE:
- case IF_ICMPLT:
- case IF_ICMPNE:
- case IFEQ:
- case IFLE:
- case IFLT:
- case IFGT:
- case IFNE:
- case IFGE:
- case IFNULL:
- case IFNONNULL:
- case GOTO:
- case JSR:
- out.writeShort(target);
- break;
-
- default:
- throw new IllegalStateException("Don't know how to write out " + getName().toUpperCase());
- }
-
- }
-
- protected int getTargetOffset() {
- if (targetInstruction == null && targetIndex == UNSET) {
- throw new ClassGenException("Target of " + super.toString(true) + " is unknown");
- }
-
- if (targetInstruction == null) {
- return targetIndex;
- } else {
- return targetInstruction.getPosition() - positionOfThisInstruction;
- }
- }
-
- /**
- * Called by InstructionList.setPositions when setting the position for every instruction. In the presence of variable length
- * instructions `setPositions' performs multiple passes over the instruction list to calculate the correct (byte) positions and
- * offsets by calling this function.
- *
- * @param offset additional offset caused by preceding (variable length) instructions
- * @param max_offset the maximum offset that may be caused by these instructions
- * @return additional offset caused by possible change of this instruction's length
- */
- protected int updatePosition(int offset, int max_offset) {
- int i = getTargetOffset();
-
- positionOfThisInstruction += offset;
-
- if (Math.abs(i) >= 32767 - max_offset && opcode != JSR_W && opcode != GOTO_W) {
- // Try and promote it to wide if we can
- if (opcode == JSR || opcode == GOTO) {
- if (opcode == JSR) {
- opcode = JSR_W;
- } else {
- opcode = GOTO_W;
- }
- return 2; // instruction jump destination grows from a short to a long
- } else {
- throw new IllegalStateException("Unable to pack method, jump (with opcode=" + opcode + ") is too far: "
- + Math.abs(i));
- }
- }
-
- return 0;
- }
-
- /**
- * Long output format:
- *
- * @param verbose long/short format switch
- * @return mnemonic for instruction
- */
- public String toString(boolean verbose) {
- String s = super.toString(verbose);
- String t = "null";
-
- if (verbose) {
- if (targetInstruction != null) {
- if (targetInstruction.getInstruction() == this) {
- t = "<points to itself>";
- } else if (targetInstruction.getInstruction() == null) {
- t = "<null destination>";
- } else {
- t = targetInstruction.getInstruction().toString(false);
- }
- }
- } else {
- if (targetInstruction != null) {
- targetIndex = getTargetOffset();
- t = "" + (targetIndex + positionOfThisInstruction);
- }
- }
-
- return s + " -> " + t;
- }
-
- /**
- * @return target offset in byte code
- */
- public final int getIndex() {
- return targetIndex;
- }
-
- /**
- * @return target of branch instruction
- */
- public InstructionHandle getTarget() {
- return targetInstruction;
- }
-
- /**
- * Set branch target
- *
- * @param target branch target
- */
- public void setTarget(InstructionHandle target) {
- notifyTarget(this.targetInstruction, target, this);
- this.targetInstruction = target;
- }
-
- /**
- * Used by BranchInstruction, LocalVariableGen, CodeExceptionGen
- */
- static final void notifyTarget(InstructionHandle oldHandle, InstructionHandle newHandle, InstructionTargeter t) {
- if (oldHandle != null) {
- oldHandle.removeTargeter(t);
- }
- if (newHandle != null) {
- newHandle.addTargeter(t);
- }
- }
-
- /**
- * Update the target destination for this instruction. If an oldHandle is provided it is checked to verify that is where the
- * target currently points to before changing it.
- *
- * @param oldHandle old target
- * @param newHandle new target
- */
- public void updateTarget(InstructionHandle oldHandle, InstructionHandle newHandle) {
- if (targetInstruction == oldHandle) {
- setTarget(newHandle);
- } else {
- throw new ClassGenException("Not targeting " + oldHandle + ", but " + targetInstruction);
- }
- }
-
- /**
- * @return true, if ih is target of this instruction
- */
- public boolean containsTarget(InstructionHandle ih) {
- return targetInstruction == ih;
- }
-
- /**
- * Inform target that it's not targeted anymore.
- */
- void dispose() {
- setTarget(null);
- targetIndex = -1;
- positionOfThisInstruction = -1;
- }
-
- public Type getType(ConstantPool cp) {
- if ((Constants.instFlags[opcode] & Constants.JSR_INSTRUCTION) != 0) {
- return new ReturnaddressType(physicalSuccessor());
- }
- return super.getType(cp);
- }
-
- /**
- * Returns an InstructionHandle to the physical successor of this JsrInstruction. <B>For this method to work, this
- * JsrInstruction object must not be shared between multiple InstructionHandle objects!</B> Formally, there must not be
- * InstructionHandle objects i, j where i != j and i.getInstruction() == this == j.getInstruction().
- *
- * @return an InstructionHandle to the "next" instruction that will be executed when RETurned from a subroutine.
- */
- public InstructionHandle physicalSuccessor() {
- InstructionHandle ih = this.targetInstruction;
-
- // Rewind!
- while (ih.getPrev() != null) {
- ih = ih.getPrev();
- }
-
- // Find the handle for "this" JsrInstruction object.
- while (ih.getInstruction() != this) {
- ih = ih.getNext();
- }
-
- InstructionHandle toThis = ih;
-
- while (ih != null) {
- ih = ih.getNext();
- if (ih != null && ih.getInstruction() == this) {
- throw new RuntimeException("physicalSuccessor() called on a shared JsrInstruction.");
- }
- }
-
- // Return the physical successor
- return toThis.getNext();
- }
-
- public boolean isIfInstruction() {
- return (Constants.instFlags[opcode] & Constants.IF_INST) != 0;
- }
-
- /**
- * Only equal if they are the same branch instruction - otherwise too risky as the targets may only temporarily be pointing at
- * the same destination.
- */
- public boolean equals(Object other) {
- return this == other;
- }
-
- public int hashCode() {
- int result = 17;
- result = opcode * 37 + result;
- return result;
- }
- }
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