codegen/types/Type.java

8  * particular file as subject to the "Classpath" exception as provided
18  * 2 along with this work; if not, write to the Free Software Foundation,
67  * Classes, with the basis for conversion weight, mapping to ASM types
69  * how to generate code for various operations.
71  * Except for ClassEmitter, this is the only class that has to know
74  * The different types know how to generate bytecode for the different
81  * of narrower to wider types. The widest type is an object. Ideally we
82  * would like as narrow types as possible for code to be efficient, e.g
106      * ASM and it saves startup time to cache the type mappings
114     /** Weights are used to decide which types are "wider" than other types */
117     /** Set way below Integer.MAX_VALUE to prevent overflow when adding weights. Objects are still heaviest. */
155      * to test.
173      * Returns the character describing the bytecode type for this value on the stack or local variable, identical to
176      * been initialized yet (it can't appear for a value pushed to the operand stack, those always have known values).
222         // Use 'Z' for boolean parameters as we need to distinguish from int
307      * Write a map of {@code int} to {@code Type} to an output stream. This is used to store deoptimization state.
337      * Read a map of {@code int} to {@code Type} from an input stream. This is used to store deoptimization state.
419      * Determines whether this type represents an primitive type according to the ECMAScript specification,
528      * @param type the second type to check
537      * Determine if a type can be assigned to from another
539      * @param type0 the first type to check
540      * @param type1 the second type to check
542      * @return true if type1 can be written to type2, false otherwise
554      * @param type the type to check against
556      * @return true if "type" can be written to this type, false otherwise
563      * Determines is this type is equivalent to another, i.e. needs no conversion
564      * to be assigned to it.
566      * @param type0 the first type to check
567      * @param type1 the second type to check
569      * @return true if this type is equivalent to type, false otherwise
619      * When doing widening for return types of a function or a ternary operator, it is not valid to widen a boolean to
621      * boolean-to-number widening. Eventually, we should address it there, but it affects too many other parts of the
642      * @param type the type to generify
663      * @param type type to check against
672      * @param type type to check against
716      * @param  other type to compare against
727      * @param  other type to compare against
773      * @param clazz the class to check
806      * @param other  the type to swap with
839      * @param type   type to pop
914      * This is the CharSequence singleton used to represent JS strings internally
1046         // EMPTY - used as a class that is absolutely not compatible with a type to represent "unknown"
1082         public Type convert(final MethodVisitor method, final Type to) {
1083             throw new UnsupportedOperationException("convert => " + to);