com.google.gwt.dev.jjs.impl

Class Pruner

java.lang.Object

com.google.gwt.dev.jjs.impl.Pruner

public class Pruner
extends Object

Remove globally unreferenced classes, interfaces, methods, parameters, and fields from the AST. This algorithm is based on having known "entry points" into the application which serve as the root(s) from which reachability is determined and everything else is rescued. Pruner determines reachability at a global level based on method calls and new operations; it does not perform any local code flow analysis. But, a local code flow optimization pass that can eliminate method calls would allow Pruner to prune additional nodes. Note: references to pruned types may still exist in the tree after this pass runs, however, it should only be in contexts that do not rely on any code generation for the pruned type. For example, it's legal to have a variable of a pruned type, or to try to cast to a pruned type. These will cause natural failures at run time; or later optimizations might be able to hard-code failures at compile time. Note: this class is limited to pruning parameters of static methods only.

Method Summary

Modifier and Type	Method and Description
static OptimizerStats	exec(JProgram program, boolean noSpecialTypes)
static OptimizerStats	exec(JProgram program, boolean noSpecialTypes, OptimizerContext optimizerCtx)
static JFieldRef	transformToNullFieldRef(JFieldRef x, JProgram program) Transform a reference to a pruned instance field into a reference to the null field, which will be used to replace x.
static JMethodCall	transformToNullMethodCall(JMethodCall x, JProgram program) Transform a call to a pruned instance method (or static impl) into a call to the null method, which will be used to replace x.

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, toString

Method Detail

exec

public static OptimizerStats exec(JProgram program,
                                  boolean noSpecialTypes,
                                  OptimizerContext optimizerCtx)

exec

public static OptimizerStats exec(JProgram program,
                                  boolean noSpecialTypes)

transformToNullFieldRef

public static JFieldRef transformToNullFieldRef(JFieldRef x,
                                                JProgram program)

Transform a reference to a pruned instance field into a reference to the null field, which will be used to replace x.

transformToNullMethodCall

public static JMethodCall transformToNullMethodCall(JMethodCall x,
                                                    JProgram program)

Transform a call to a pruned instance method (or static impl) into a call to the null method, which will be used to replace x.