/*******************************************************************************
* Copyright (c) 2007 IBM Corporation.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package com.ibm.wala.ssa;
import com.ibm.wala.util.collections.Pair;
/**
* The {@link SSABuilder} consults this as an oracle to decide how to insert {@link SSAPiInstruction}s
*/
public interface SSAPiNodePolicy {
/**
* Do we need to introduce a new name for some value immediately after a call?
*
* If so, returns a pair consisting of the value number needing renaming, and the instruction which should be recorded as the
* cause of the pi instruction
*
* @param call the call instruction in question
* @param symbolTable current state of the symbol table for the IR under construction
* @return description of the necessary pi instruction, or null if no pi instruction is needed.
*/
Pair<Integer, SSAInstruction> getPi(SSAAbstractInvokeInstruction call, SymbolTable symbolTable);
/**
* Do we need to introduce a new name for some value after deciding on an outcome for a conditional branch instruction?
*
* If so, returns a pair consisting of the value number needing renaming, and the instruction which should be recorded as the
* cause of the pi instruction
*
* @param cond the conditional branch instruction in question
* @param def1 the {@link SSAInstruction} that defs cond.getUse(0), or null if none
* @param def2 the {@link SSAInstruction} that defs cond.getUse(1), or null if none
* @param symbolTable current state of the symbol table for the IR under construction
* @return description of the necessary pi instruction, or null if no pi instruction is needed.
*/
Pair<Integer, SSAInstruction> getPi(SSAConditionalBranchInstruction cond, SSAInstruction def1, SSAInstruction def2,
SymbolTable symbolTable);
}