Package EDU.purdue.cs.bloat.tbaa

Class TypeInference

java.lang.Object

EDU.purdue.cs.bloat.tbaa.TypeInference

public class TypeInference
extends java.lang.Object

Typed-based alias analysis requires that we know the types of all entities in a method. However, local variables and stack variables do not have declared types. Thus, we have to infer them.

TypeInference uses a simpilified version of everyone's favorite type inference algorithm from Object-Oriented Type Systems by Palsberg and Schwartzbach. It is simplified in that no interprocedural type information is calculated.

Here's how it works. Entities such as method arguments, fields, and constants have a known type. This known type is expressed in a constraint that constraints the entity to its type. Operations involving assignment (also phi-statements and stack operations) propagate these constraints to the targets of the assignments.

Field Summary

Fields

Modifier and Type	Field	Description
static boolean	DEBUG

Constructor Summary

Constructors

Constructor	Description
TypeInference()

Method Summary

Modifier and Type	Method	Description
static void	transform(FlowGraph cfg, ClassHierarchy hier)	Traverses the control flow graph and with the help of a number of vistors performs type-based alias analysis.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEBUG

public static boolean DEBUG

Constructor Detail

TypeInference

public TypeInference()

Method Detail

transform

public static void transform(FlowGraph cfg,
                             ClassHierarchy hier)

Traverses the control flow graph and with the help of a number of vistors performs type-based alias analysis.

Parameters:

cfg - The control flow graph on which to perform TBAA.

hier - A class heirarchy used for getting information about Types (classes).

See Also:

SSAGraph, ComponentVisitor, TreeVisitor