Stephen Haberman has uploaded a new change for review.
https://gwt-review.googlesource.com/3440
Change subject: Optimize initializing fields at the top scope.
......................................................................
Optimize initializing fields at the top scope.
Change-Id: I97a06eb36396a8b8659ce9a025b21a9cf93d0500
---
M dev/core/src/com/google/gwt/dev/jjs/impl/GenerateJavaScriptAST.java
1 file changed, 33 insertions(+), 3 deletions(-)
diff --git
a/dev/core/src/com/google/gwt/dev/jjs/impl/GenerateJavaScriptAST.java
b/dev/core/src/com/google/gwt/dev/jjs/impl/GenerateJavaScriptAST.java
index 240f6a0..3606478 100644
--- a/dev/core/src/com/google/gwt/dev/jjs/impl/GenerateJavaScriptAST.java
+++ b/dev/core/src/com/google/gwt/dev/jjs/impl/GenerateJavaScriptAST.java
@@ -15,10 +15,10 @@
*/
package com.google.gwt.dev.jjs.impl;
+import com.google.gwt.core.ext.PropertyOracle;
import com.google.gwt.core.ext.linker.CastableTypeMap;
import com.google.gwt.core.ext.linker.impl.StandardCastableTypeMap;
import com.google.gwt.core.ext.linker.impl.StandardSymbolData;
-import com.google.gwt.core.ext.PropertyOracle;
import com.google.gwt.dev.jjs.HasSourceInfo;
import com.google.gwt.dev.jjs.InternalCompilerException;
import com.google.gwt.dev.jjs.JsOutputOption;
@@ -859,7 +859,7 @@
JVariable target = x.getVariableRef().getTarget();
if (target instanceof JField) {
JField field = (JField) target;
- if (field.getLiteralInitializer() != null && (field.isStatic() ||
field.isFinal())) {
+ if (initializeAtTopScope(field)) {
// Will initialize at top scope; no need to double-initialize.
push(null);
return;
@@ -893,7 +893,7 @@
@Override
public void endVisit(JField x, Context ctx) {
// if we need an initial value, create an assignment
- if (x.getLiteralInitializer() != null && (x.isFinal() ||
x.isStatic())) {
+ if (initializeAtTopScope(x)) {
// setup the constant value
accept(x.getLiteralInitializer());
} else if (x.getEnclosingType() == program.getTypeJavaLangObject()) {
@@ -2207,6 +2207,36 @@
jsInvocation.setQualifier(names.get(clinitMethod).makeRef(sourceInfo));
return jsInvocation;
}
+
+ /**
+ * If a field is a literal, we can potentially treat it as immutable
and assign it once on the
+ * prototype, to be reused by all instances of the class, instead of
re-assigning the same
+ * literal in each constructor.
+ *
+ * Technically, to match JVM semantics, we should only do this for
final or static fields. For
+ * non-final/non-static fields, a super class's cstr should actually
see default values (not the
+ * literal initializer) before the subclass's cstr runs.
+ *
+ * However, this is slow for an admittedly uncommon case (a super
class using a virtual method
+ * to read a subclass's field), so we apply some hueristics to see if
we can do the fast thing
+ * (initialize at the top/prototype scope).
+ */
+ private boolean initializeAtTopScope(JField x) {
+ if (x.getLiteralInitializer() != null) {
+ if (x.isFinal() || x.isStatic()) {
+ // we can definitely initialize at top-scope, as that matches
the JVM
+ return true;
+ } else if (x.getEnclosingType().getSuperClass() ==
program.getTypeJavaLangObject()) {
+ // the superclass is j.l.Object, which we know won't access any
of a subclass's fields
+ return true;
+ } else {
+ // TODO Look at our superclass constructors to see if any of
them call a virtual
+ // method. For now, assume that they might.
+ return false;
+ }
+ }
+ return false;
+ }
}
private static class JavaToJsOperatorMap {
--
To view, visit https://gwt-review.googlesource.com/3440
To unsubscribe, visit https://gwt-review.googlesource.com/settings
Gerrit-MessageType: newchange
Gerrit-Change-Id: I97a06eb36396a8b8659ce9a025b21a9cf93d0500
Gerrit-PatchSet: 1
Gerrit-Project: gwt
Gerrit-Branch: master
Gerrit-Owner: Stephen Haberman <[email protected]>
--
http://groups.google.com/group/Google-Web-Toolkit-Contributors
---
You received this message because you are subscribed to the Google Groups "GWT Contributors" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
For more options, visit https://groups.google.com/groups/opt_out.
