private Object evaluateSafely(final Expression expr) {
if (expr instanceof IdentNode) {
return runtimeScope == null
? null
: evaluatePropertySafely(runtimeScope, ((IdentNode) expr).getName());
}
if (expr instanceof AccessNode) {
final AccessNode accessNode = (AccessNode) expr;
final Object base = evaluateSafely(accessNode.getBase());
if (!(base instanceof ScriptObject)) {
return null;
}
return evaluatePropertySafely((ScriptObject) base, accessNode.getProperty());
}
return null;
}
@Override
public boolean enterAccessNode(final AccessNode accessNode) {
tagNeverOptimistic(accessNode.getBase());
return true;
}
@Override
public boolean enterAccessNode(final AccessNode accessNode) {
curExpr = new MemberSelectTreeImpl(accessNode, translateExpr(accessNode.getBase()));
return false;
}
private Type getEvaluatedType(final Optimistic expr) {
if (expr instanceof IdentNode) {
if (runtimeScope == null) {
return null;
}
return getPropertyType(runtimeScope, ((IdentNode) expr).getName());
} else if (expr instanceof AccessNode) {
final AccessNode accessNode = (AccessNode) expr;
final Object base = evaluateSafely(accessNode.getBase());
if (!(base instanceof ScriptObject)) {
return null;
}
return getPropertyType((ScriptObject) base, accessNode.getProperty());
} else if (expr instanceof IndexNode) {
final IndexNode indexNode = (IndexNode) expr;
final Object base = evaluateSafely(indexNode.getBase());
if (base instanceof NativeArray || base instanceof ArrayBufferView) {
// NOTE: optimistic array getters throw UnwarrantedOptimismException based on the type of
// their
// underlying array storage, not based on values of individual elements. Thus, a
// LongArrayData will
// throw UOE for every optimistic int linkage attempt, even if the long value being returned
// in the
// first invocation would be representable as int. That way, we can presume that the array's
// optimistic
// type is the most optimistic type for which an element getter has a chance of executing
// successfully.
return ((ScriptObject) base).getArray().getOptimisticType();
}
} else if (expr instanceof CallNode) {
// Currently, we'll only try to guess the return type of immediately invoked function
// expressions with no
// parameters, that is (function() { ... })(). We could do better, but these are all
// heuristics and we can
// gradually introduce them as needed. An easy one would be to do the same for .call(this)
// idiom.
final CallNode callExpr = (CallNode) expr;
final Expression fnExpr = callExpr.getFunction();
if (fnExpr instanceof FunctionNode) {
final FunctionNode fn = (FunctionNode) fnExpr;
if (callExpr.getArgs().isEmpty()) {
final RecompilableScriptFunctionData data = compiler.getScriptFunctionData(fn.getId());
if (data != null) {
final Type returnType =
Type.typeFor(data.getReturnType(EMPTY_INVOCATION_TYPE, runtimeScope));
if (returnType == Type.BOOLEAN) {
// We don't have optimistic booleans. In fact, optimistic call sites getting back
// boolean
// currently deoptimize all the way to Object.
return Type.OBJECT;
}
assert returnType == Type.INT
|| returnType == Type.LONG
|| returnType == Type.NUMBER
|| returnType == Type.OBJECT;
return returnType;
}
}
}
}
return null;
}