EDU.purdue.cs.bloat.ssa
Class SSA

java.lang.Object
  |
  +--EDU.purdue.cs.bloat.ssa.SSA

public class SSA

extends java.lang.Object

Compute the SSA form of the control flow graph and build FUD chains.

The SSA algorithm is from:

    R. Cytron, J. Ferrante J, B. K. Rosen, M. N. Wegman, and F. K. Zadeck,
    "Efficiently Computing Static Single Assignment Form and the Control
    Dependence Graph", TOPLAS, 13(4): 451-490, October 1991.
 

I made modifications to the algorithm to compute FUD chains and to run the algorithm separately for each variable similar to the SSAPRE algorithm. Making a separate pass for each variable allows variables to be added incrementally.

Field Summary

static boolean

DEBUG

Constructor Summary

SSA()

Method Summary

static void	transform(FlowGraph cfg) Transforms a control flow graph into Single Static Assignment (SSA) form.
static void	transform(FlowGraph cfg, SSAConstructionInfo info) Performs the actions necessary to convert a CFG into SSA form with respect to one variable.

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

SSA

public SSA()

Method Detail

transform

public static void transform(FlowGraph cfg)

Transforms a control flow graph into Single Static Assignment (SSA) form. First, the CFG is traversed and a list of all variables (both local and stack) eligible for SSA renaming is compiled. Variables are represented by instances of SSAConstructionInfo. Each of these variables is then transformed.

See Also:

transform(EDU.purdue.cs.bloat.cfg.FlowGraph), SSAConstructionInfo

transform

public static void transform(FlowGraph cfg,
                             SSAConstructionInfo info)

Performs the actions necessary to convert a CFG into SSA form with respect to one variable. The variable's information is stored in the SSAConstructionInfo.