soot.coffi.BasicBlock Maven / Gradle / Ivy
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package soot.coffi;
/*-
* #%L
* Soot - a J*va Optimization Framework
* %%
* Copyright (C) 1997 Clark Verbrugge
* %%
* This program 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 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 Lesser Public License for more details.
*
* You should have received a copy of the GNU General Lesser Public
* License along with this program. If not, see
* .
* #L%
*/
import java.util.List;
import java.util.Set;
import java.util.Vector;
import soot.G;
import soot.jimple.Stmt;
import soot.util.ArraySet;
/**
* 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;
}
}