/**
* Transform a call to a pruned instance method (or static impl) into a call to the null method,
* which will be used to replace <code>x</code>.
*/
public static JMethodCall transformToNullMethodCall(JMethodCall x, JProgram program) {
JExpression instance = x.getInstance();
List<JExpression> args = x.getArgs();
if (program.isStaticImpl(x.getTarget())) {
instance = args.get(0);
args = args.subList(1, args.size());
} else {
/*
* We assert that method must be non-static, otherwise it would have been
* rescued.
*/
// assert !x.getTarget().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.getTarget().isStatic() && instance == null) {
instance = program.getLiteralNull();
}
}
assert (instance != null);
if (!instance.hasSideEffects()) {
instance = program.getLiteralNull();
}
JMethodCall newCall =
new JMethodCall(
x.getSourceInfo(),
instance,
program.getNullMethod(),
primitiveTypeOrNullTypeOrArray(program, x.getType()));
// Retain the original arguments, they will be evaluated for side effects.
for (JExpression arg : args) {
if (arg.hasSideEffects()) {
newCall.addArg(arg);
}
}
return newCall;
}
/**
* 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;
}
/** Returns an ast node representing the expression {@code expression != null}. */
public static JExpression createOptimizedNotNullComparison(
JProgram program, SourceInfo info, JExpression expression) {
JReferenceType type = (JReferenceType) expression.getType();
if (type.isNullType()) {
return program.getLiteralBoolean(false);
}
if (!type.canBeNull()) {
return createOptimizedMultiExpression(expression, program.getLiteralBoolean(true));
}
return new JBinaryOperation(
info,
program.getTypePrimitiveBoolean(),
JBinaryOperator.NEQ,
expression,
program.getLiteralNull());
}