Rescue volatile fields that have a live assignment to them. This is helpful
in test cases; you can now keep an expression live by assigning its result
to a volatile field.
Review by: scottb
git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@2985 8db76d5a-ed1c-0410-87a9-c151d255dfc7
diff --git a/dev/core/src/com/google/gwt/dev/jjs/impl/Pruner.java b/dev/core/src/com/google/gwt/dev/jjs/impl/Pruner.java
index 6fb1a31..6ceec64 100644
--- a/dev/core/src/com/google/gwt/dev/jjs/impl/Pruner.java
+++ b/dev/core/src/com/google/gwt/dev/jjs/impl/Pruner.java
@@ -111,6 +111,7 @@
}
}
+ @Override
public void endVisit(JDeclarationStatement x, Context ctx) {
// The variable may have been pruned.
if (!referencedNonTypes.contains(x.getVariableRef().getTarget())) {
@@ -485,8 +486,10 @@
// Don't rescue variables that are merely assigned to and never read
boolean doSkip = false;
JExpression lhs = x.getLhs();
- if (lhs.hasSideEffects()) {
- // cannot skip
+ if (lhs.hasSideEffects() || isVolatileField(lhs)) {
+ // If the lhs has side effects, skipping it would lose the side effect.
+ // If the lhs is volatile, also keep it. This behavior provides a useful
+ // idiom for test cases to prevent code from being pruned.
} else if (lhs instanceof JLocalRef) {
// locals are ok to skip
doSkip = true;
@@ -554,6 +557,7 @@
return false;
}
+ @Override
public boolean visit(JDeclarationStatement x, Context ctx) {
/*
* A declaration by itself doesn't rescue a local (even if it has an
@@ -750,6 +754,17 @@
return true;
}
+ private boolean isVolatileField(JExpression x) {
+ if (x instanceof JFieldRef) {
+ JFieldRef xFieldRef = (JFieldRef) x;
+ if (xFieldRef.getField().isVolatile()) {
+ return true;
+ }
+ }
+
+ return false;
+ }
+
/**
* Subclasses of JavaScriptObject are never instantiated directly. They are
* created "magically" when a JSNI method passes a reference to an existing
