sandmark.obfuscate.boolsplitter.dtree
Class StackOptimizer

java.lang.Object
  |
  +--sandmark.obfuscate.boolsplitter.dtree.StackOptimizer

public class StackOptimizer

extends java.lang.Object

StackOptimizer analyzes the relative distances of various uses of the same definition of a local variable to add dups and swaps to the bytecode and eliminate loads and stores.

Author:

Thomas VanDrunen

Field Summary

(package private) static boolean	DEBUG
(package private) java.util.Hashtable	defInfoMap
(package private) Block	owningBlock
(package private) java.util.Hashtable	useInfoMap

Constructor Summary

StackOptimizer(Block owningBlock)

Method Summary

int	dup_x1s(LocalExpr expr)
int	dup_x2s(LocalExpr expr)
int	dups(LocalExpr expr)
void	infoDisplay(LocalExpr expr)
boolean	onStack(LocalExpr expr)
void	optimize() Optimize runs the algorithm for analyzing the tree, looking for opportunities to replaces stores and loads with dups and swaps.
static void	optimizeCFG(FlowGraph cfg)
boolean	shouldStore(LocalExpr expr) Various methods used by CodeGenerator, used as an interface into the information in defInfoMap and useInfoMap
boolean	shouldSwap(LocalExpr expr)

Methods inherited from class java.lang.Object

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

Field Detail

DEBUG

static boolean DEBUG

defInfoMap

java.util.Hashtable defInfoMap

useInfoMap

java.util.Hashtable useInfoMap

owningBlock

Block owningBlock

Constructor Detail

StackOptimizer

public StackOptimizer(Block owningBlock)

Method Detail

optimizeCFG

public static void optimizeCFG(FlowGraph cfg)

optimize

public void optimize()

Optimize runs the algorithm for analyzing the tree, looking for opportunities to replaces stores and loads with dups and swaps. It initiates several visitors, and information is sotred in defInfoMap and useInfoMap

shouldStore

public boolean shouldStore(LocalExpr expr)

Various methods used by CodeGenerator, used as an interface into the information in defInfoMap and useInfoMap

dups

public int dups(LocalExpr expr)

dup_x1s

public int dup_x1s(LocalExpr expr)

dup_x2s

public int dup_x2s(LocalExpr expr)

onStack

public boolean onStack(LocalExpr expr)

shouldSwap

public boolean shouldSwap(LocalExpr expr)

infoDisplay

public void infoDisplay(LocalExpr expr)