soot.coffi.BasicBlock Maven / Gradle / Ivy
/* Soot - a J*va Optimization Framework
* Copyright (C) 1997 Clark Verbrugge
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/*
* Modified by the Sable Research Group and others 1997-1999.
* See the 'credits' file distributed with Soot for the complete list of
* contributors. (Soot is distributed at http://www.sable.mcgill.ca/soot)
*/
package soot.coffi;
import java.util.*;
import soot.jimple.Stmt;
import soot.util.*;
import soot.*;
/** Represents one basic block in a control flow graph.
* @see CFG
* @see ClassFile#parse
* @author Clark Verbrugge
*/
class BasicBlock {
/** Number of instructions in this block. */
public int size;
/** Head of the list of instructions. */
public Instruction head;
/** Tail of the list of instructions.
*
* Normally, the last instruction will have a next pointer with value
* null. After a Instruction sequences are reconstructed though,
* the instruction lists
* are rejoined in order, and so the tail instruction will not
* have a null next pointer.
* @see CFG#reconstructInstructions
*/
public Instruction tail;
/** Vector of predecessor BasicBlocks.
* @see java.util.Vector
*/
public Vector succ;
/** Vector of successor BasicBlocks.
* @see java.util.Vector
*/
public Vector pred;
public boolean inq;
/** Flag for whether starting an exception or not. */
public boolean beginException;
/** Flag for whether starting main code block or not. */
public boolean beginCode;
/** Flag for semantic stack analysis fixup pass.
* @see CFG#jimplify
*/
boolean done;
/** Next BasicBlock in the CFG, in the parse order. */
public BasicBlock next;
/** Unique (among basic blocks) id. */
public long id; // unique id
List statements;
Set addressesToFixup = new ArraySet();
soot.jimple.Stmt getHeadJStmt()
{
return statements.get(0);
}
soot.jimple.Stmt getTailJStmt()
{
return statements.get(statements.size() - 1);
}
public BasicBlock(Instruction insts) {
id = G.v().coffi_BasicBlock_ids++;
head = insts;
tail = head;
size = 0;
if (head!=null) {
size++;
while (tail.next!=null) {
size++;
tail = tail.next;
}
}
succ = new Vector(2,10);
pred = new Vector(2,3);
}
public BasicBlock(Instruction headinsn, Instruction tailinsn)
{
id = G.v().coffi_BasicBlock_ids++;
head = headinsn;
tail = tailinsn;
succ = new Vector(2,10);
pred = new Vector(2,3);
}
/** Computes a hash code for this block from the label of the
* first instruction in its contents.
* @return the hash code.
* @see Instruction#label
*/
public int hashCode() {
return (new Integer(head.label)).hashCode();
}
/** True if this block represents the same piece of code. Basically
* compares labels of the head instructions.
* @param b block to compare against.
* @return true if they do, false if they don't.
*/
public boolean equals(BasicBlock b) {
return (this == b);
}
/** For printing the string "BB: " + id.
*/
public String toString() { return "BB: " + id; }
}