com.google.gwt.dev.js

Class DuplicateExecuteOnceRemover

java.lang.Object

com.google.gwt.dev.js.ast.JsVisitor

com.google.gwt.dev.js.ast.JsModVisitor

com.google.gwt.dev.js.DuplicateExecuteOnceRemover

public class DuplicateExecuteOnceRemover
extends JsModVisitor

This is used to clean up duplication invocations of functions that should only be executed once, such as clinit functions. Whenever there is a possible branch in program flow, the remover will create a new instance of itself to handle the possible branches. We don't look at combining branch choices. This will not produce the most efficient elimination of duplicated calls, but it handles the general case and is simple to verify.

Field Summary

Fields inherited from class com.google.gwt.dev.js.ast.JsModVisitor

didChange

Fields inherited from class com.google.gwt.dev.js.ast.JsVisitor

LVALUE_CONTEXT, UNMODIFIABLE_CONTEXT

Constructor Summary

Constructors

Constructor and Description
DuplicateExecuteOnceRemover(JsProgram program)
DuplicateExecuteOnceRemover(JsProgram program, Set<JsFunction> alreadyCalled)

Method Summary

Modifier and Type	Method and Description
static OptimizerStats	exec(JsProgram program) Static entry point used by JavaToJavaScriptCompiler.
boolean	visit(JsBinaryOperation x, JsContext ctx) Look for comma expressions that contain duplicate calls and handle the conditional-evaluation case of logical and/or operations.
boolean	visit(JsBlock x, JsContext ctx) Most of the branching statements (as well as JsFunctions) will visit with a JsBlock, so we don't need to explicitly enumerate all JsStatement subtypes.
boolean	visit(JsCase x, JsContext ctx)
boolean	visit(JsConditional x, JsContext ctx)
boolean	visit(JsDefault x, JsContext ctx)
boolean	visit(JsExprStmt x, JsContext ctx)
boolean	visit(JsForIn x, JsContext ctx)
boolean	visit(JsFor x, JsContext ctx)
boolean	visit(JsIf x, JsContext ctx)
boolean	visit(JsInvocation x, JsContext ctx) Possibly record that we've seen a call in the current context.
boolean	visit(JsWhile x, JsContext ctx)

Methods inherited from class com.google.gwt.dev.js.ast.JsModVisitor

checkReplacement, didChange, doAccept, doAcceptList, doAcceptLvalue, doAcceptWithInsertRemove

Methods inherited from class com.google.gwt.dev.js.ast.JsVisitor

accept, acceptList, acceptLvalue, acceptWithInsertRemove, doTraverse, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, endVisit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, toString

Constructor Detail

DuplicateExecuteOnceRemover

public DuplicateExecuteOnceRemover(JsProgram program)

DuplicateExecuteOnceRemover

public DuplicateExecuteOnceRemover(JsProgram program,
                                   Set<JsFunction> alreadyCalled)

Method Detail

visit

public boolean visit(JsBinaryOperation x,
                     JsContext ctx)

Look for comma expressions that contain duplicate calls and handle the conditional-evaluation case of logical and/or operations.

Overrides:

visit in class JsVisitor

visit

public boolean visit(JsBlock x,
                     JsContext ctx)

Most of the branching statements (as well as JsFunctions) will visit with a JsBlock, so we don't need to explicitly enumerate all JsStatement subtypes.

Overrides:

visit in class JsVisitor

visit

public boolean visit(JsCase x,
                     JsContext ctx)

Overrides:

visit in class JsVisitor

visit

public boolean visit(JsConditional x,
                     JsContext ctx)

Overrides:

visit in class JsVisitor

visit

public boolean visit(JsDefault x,
                     JsContext ctx)

Overrides:

visit in class JsVisitor

visit

public boolean visit(JsExprStmt x,
                     JsContext ctx)

Overrides:

visit in class JsVisitor

visit

public boolean visit(JsFor x,
                     JsContext ctx)

Overrides:

visit in class JsVisitor

visit

public boolean visit(JsForIn x,
                     JsContext ctx)

Overrides:

visit in class JsVisitor

visit

public boolean visit(JsIf x,
                     JsContext ctx)

Overrides:

visit in class JsVisitor

visit

public boolean visit(JsInvocation x,
                     JsContext ctx)

Possibly record that we've seen a call in the current context.

Overrides:

visit in class JsVisitor

visit

public boolean visit(JsWhile x,
                     JsContext ctx)

Overrides:

visit in class JsVisitor

exec

public static OptimizerStats exec(JsProgram program)

Static entry point used by JavaToJavaScriptCompiler.