| // ASM: a very small and fast Java bytecode manipulation framework |
| // Copyright (c) 2000-2011 INRIA, France Telecom |
| // 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. Neither the name of the copyright holders nor the names of its |
| // contributors may be used to endorse or promote products derived from |
| // this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
| // AND ANY EXPRESS 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 COPYRIGHT OWNER OR 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. |
| package org.apache.tapestry5.internal.plastic.asm.tree.analysis; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| import org.apache.tapestry5.internal.plastic.asm.tree.JumpInsnNode; |
| import org.apache.tapestry5.internal.plastic.asm.tree.LabelNode; |
| |
| /** |
| * A method subroutine (corresponds to a JSR instruction). |
| * |
| * @author Eric Bruneton |
| */ |
| final class Subroutine { |
| |
| /** The start of this subroutine. */ |
| final LabelNode start; |
| |
| /** |
| * The local variables that are read or written by this subroutine. The i-th element is true if |
| * and only if the local variable at index i is read or written by this subroutine. |
| */ |
| final boolean[] localsUsed; |
| |
| /** The JSR instructions that jump to this subroutine. */ |
| final List<JumpInsnNode> callers; |
| |
| /** |
| * Constructs a new {@link Subroutine}. |
| * |
| * @param start the start of this subroutine. |
| * @param maxLocals the local variables that are read or written by this subroutine. |
| * @param caller a JSR instruction that jump to this subroutine. |
| */ |
| Subroutine(final LabelNode start, final int maxLocals, final JumpInsnNode caller) { |
| this.start = start; |
| this.localsUsed = new boolean[maxLocals]; |
| this.callers = new ArrayList<JumpInsnNode>(); |
| callers.add(caller); |
| } |
| |
| /** |
| * Constructs a copy of the given {@link Subroutine}. |
| * |
| * @param subroutine the subroutine to copy. |
| */ |
| Subroutine(final Subroutine subroutine) { |
| this.start = subroutine.start; |
| this.localsUsed = new boolean[subroutine.localsUsed.length]; |
| this.callers = new ArrayList<JumpInsnNode>(subroutine.callers); |
| System.arraycopy(subroutine.localsUsed, 0, this.localsUsed, 0, subroutine.localsUsed.length); |
| } |
| |
| /** |
| * Merges the given subroutine into this subroutine. The local variables read or written by the |
| * given subroutine are marked as read or written by this one, and the callers of the given |
| * subroutine are added as callers of this one (if both have the same start). |
| * |
| * @param subroutine another subroutine. This subroutine is left unchanged by this method. |
| * @return whether this subroutine has been modified by this method. |
| */ |
| public boolean merge(final Subroutine subroutine) { |
| boolean changed = false; |
| for (int i = 0; i < localsUsed.length; ++i) { |
| if (subroutine.localsUsed[i] && !localsUsed[i]) { |
| localsUsed[i] = true; |
| changed = true; |
| } |
| } |
| if (subroutine.start == start) { |
| for (int i = 0; i < subroutine.callers.size(); ++i) { |
| JumpInsnNode caller = subroutine.callers.get(i); |
| if (!callers.contains(caller)) { |
| callers.add(caller); |
| changed = true; |
| } |
| } |
| } |
| return changed; |
| } |
| } |