@Override
public void endVisit(JFieldRef x, Context ctx) {
// Handle l-values at a higher level.
if (lValues.peek() == x) {
return;
}
if (isPruned(x.getField())) {
// The field is gone; replace x by a null field reference.
JFieldRef fieldRef = transformToNullFieldRef(x, program);
ctx.replaceMe(fieldRef);
}
}
/**
* Transform a reference to a pruned instance field into a reference to the null field, which will
* be used to replace <code>x</code>.
*/
public static JFieldRef transformToNullFieldRef(JFieldRef x, JProgram program) {
JExpression instance = x.getInstance();
/*
* We assert that field must be non-static if it's an rvalue, otherwise it
* would have been rescued.
*/
// assert !x.getField().isStatic();
/*
* HACK HACK HACK: ControlFlowAnalyzer has special hacks for dealing with
* ClassLiterals, which causes the body of ClassLiteralHolder's clinit to
* never be rescured. This in turn causes invalid references to static
* methods, which violates otherwise good assumptions about compiler
* operation.
*
* TODO: Remove this when ControlFlowAnalyzer doesn't special-case
* CLH.clinit().
*/
if (x.getField().isStatic() && instance == null) {
instance = program.getLiteralNull();
}
assert instance != null;
if (!instance.hasSideEffects()) {
instance = program.getLiteralNull();
}
JFieldRef fieldRef =
new JFieldRef(
x.getSourceInfo(),
instance,
program.getNullField(),
x.getEnclosingType(),
primitiveTypeOrNullTypeOrArray(program, x.getType()));
return fieldRef;
}
private JExpression makeReplacementForAssignment(
SourceInfo info, JVariableRef variableRef, JExpression rhs) {
// Replace with a multi, which may wind up empty.
JMultiExpression multi = new JMultiExpression(info);
// If the lhs is a field ref, evaluate it first.
if (variableRef instanceof JFieldRef) {
JFieldRef fieldRef = (JFieldRef) variableRef;
JExpression instance = fieldRef.getInstance();
if (instance != null) {
multi.addExpressions(instance);
}
}
// If there is an rhs, evaluate it second.
if (rhs != null) {
multi.addExpressions(rhs);
}
if (multi.getNumberOfExpressions() == 1) {
return multi.getExpression(0);
} else {
return multi;
}
}