Type getOptimisticType(final Optimistic node) {
assert compiler.useOptimisticTypes();
final int programPoint = node.getProgramPoint();
final Type validType = compiler.getInvalidatedProgramPointType(programPoint);
if (validType != null) {
return validType;
}
final Type mostOptimisticType = node.getMostOptimisticType();
final Type evaluatedType = getEvaluatedType(node);
if (evaluatedType != null) {
if (evaluatedType.widerThan(mostOptimisticType)) {
final Type newValidType =
evaluatedType.isObject() || evaluatedType.isBoolean() ? Type.OBJECT : evaluatedType;
// Update invalidatedProgramPoints so we don't re-evaluate the expression next time. This is
// a heuristic
// as we're doing a tradeoff. Re-evaluating expressions on each recompile takes time, but it
// might
// notice a widening in the type of the expression and thus prevent an unnecessary
// deoptimization later.
// We'll presume though that the types of expressions are mostly stable, so if we evaluated
// it in one
// compilation, we'll keep to that and risk a low-probability deoptimization if its type
// gets widened
// in the future.
compiler.addInvalidatedProgramPoint(node.getProgramPoint(), newValidType);
}
return evaluatedType;
}
return mostOptimisticType;
}
private static ArrayType getArrayType(final Type elementType) {
if (elementType.isInteger()) {
return Type.INT_ARRAY;
} else if (elementType.isLong()) {
return Type.LONG_ARRAY;
} else if (elementType.isNumeric()) {
return Type.NUMBER_ARRAY;
} else {
return Type.OBJECT_ARRAY;
}
}
static Object computePresets(
final Expression[] value, final Type elementType, final int[] postsets) {
assert !elementType.isUnknown();
if (elementType.isInteger()) {
return presetIntArray(value, postsets);
} else if (elementType.isLong()) {
return presetLongArray(value, postsets);
} else if (elementType.isNumeric()) {
return presetDoubleArray(value, postsets);
} else {
return presetObjectArray(value, postsets);
}
}
private static Type getPropertyType(final ScriptObject sobj, final String name) {
final FindProperty find = sobj.findProperty(name, true);
if (find == null) {
return null;
}
final Property property = find.getProperty();
final Class<?> propertyClass = property.getType();
if (propertyClass == null) {
// propertyClass == null means its value is Undefined. It is probably not initialized yet, so
// we won't make
// a type assumption yet.
return null;
} else if (propertyClass.isPrimitive()) {
return Type.typeFor(propertyClass);
}
final ScriptObject owner = find.getOwner();
if (property.hasGetterFunction(owner)) {
// Can have side effects, so we can't safely evaluate it; since !propertyClass.isPrimitive(),
// it's Object.
return Type.OBJECT;
}
// Safely evaluate the property, and return the narrowest type for the actual value (e.g.
// Type.INT for a boxed
// integer).
final Object value =
property.needsDeclaration()
? ScriptRuntime.UNDEFINED
: property.getObjectValue(owner, owner);
if (value == ScriptRuntime.UNDEFINED) {
return null;
}
return Type.typeFor(JSType.unboxedFieldType(value));
}
private static Type computeElementType(final Expression[] value) {
Type widestElementType = Type.INT;
for (final Expression elem : value) {
if (elem == null) {
widestElementType =
widestElementType.widest(Type.OBJECT); // no way to represent undefined as number
break;
}
final Type type = elem.getType().isUnknown() ? Type.OBJECT : elem.getType();
if (type.isBoolean()) {
// TODO fix this with explicit boolean types
widestElementType = widestElementType.widest(Type.OBJECT);
break;
}
widestElementType = widestElementType.widest(type);
if (widestElementType.isObject()) {
break;
}
}
return widestElementType;
}
/**
* Get the element type of this array literal
*
* @return element type
*/
public Type getElementType() {
assert !elementType.isUnknown() : this + " has elementType=unknown";
return elementType;
}
@Override
public Type getType() {
return Type.typeFor(NativeArray.class);
}
@Override
public Type getType() {
return Type.typeFor(value.getClass());
}
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;
}
