Add extra parameter for initialized carrier

[biboudis]

Existing Approach

Currently the pattern-declaration and pattern-use site look like the following:

• Pattern-declaration site

Currently, on the pattern-declaration site the carrier creation is taking place inside the method site:

pattern Point(int x, int y) {
    match Point(1, 2);
}
// translates to
static Object \^dinit\_:Point:I:I(ClassPatternDeclarations$Point) {
    int x = 1;
    int y = 2;
    Object carrier = <ldc> [static returnType =  MethodType.methodType(Object.class, int.class, int.class)] Carriers.initializingConstructor(returnType);
    return carrier.invoke(x, y);
}

• Pattern-use site

Let's observe how a pattern site is translated:

o instanceof Point(int x, int y)
// translates to
Point p = (Point) o;
Carrier c = <invokedynamic> <ConstantCallSite(Point.\^dinit\_:Point:I:I(p))>; // ConstantCallSite calculated from PatternBootstrap
...
MethodHandle component$0 = <ldc> [static arg = MethodType.methodType(Object.class, int.class, int.class)] Carriers.component(arg, 0);
MethodHandle component$1 = <ldc> [static arg = MethodType.methodType(Object.class, int.class, int.class)] Carriers.component(arg, 1);
...
int $0 = component$0.invoke(c);
// safeguard the cast for x -- identity here
int $1 = component$1.invoke(c);
// safeguard the cast for y -- also identity here
...

Adjustment

This PR adds one extra parameter on all translated methods in the end (the deconstructor/static method, the instance pattern/instance method, and the static pattern/static method) to decouple the creation of the carrier from the body of the pattern itself.

• New Pattern-declaration site

We introduce an additional MethodHandle:

static Object \^dinit\_:Point:I:I(ClassPatternDeclarations$Point, MethodHandle carrier) {
    int x = 1;
    int y = 2;
    return carrier.invoke(x, y);
}

• New Pattern-use site

The extractor should be calculated and shared per client use-site:

o instanceof Point(int x, int y)
// translates to
Point p = (Point) o;
...
MethodHandle carrierExtractor = <ldc>[static arg = MethodType.methodType(Object.class, int.class, int.class)] Carriers.initializingConstructor(arg);
Carrier c = <invokedynamic> <ConstantCallSite(Point.\^dinit\_:Point:I:I(p, carrierExtractor))>; // ConstantCallSite calculated from PatternBootstrap
...
MethodHandle component$0 = <ldc> [static arg = MethodType.methodType(Object.class, int.class, int.class)] Carriers.component(arg, 0);
MethodHandle component$1 = <ldc> [static arg = MethodType.methodType(Object.class, int.class, int.class)] Carriers.component(arg, 1);
...
int $0 = component$0.invoke(c);
// safeguard the cast for x -- identity here
int $1 = component$1.invoke(c);
// safeguard the cast for y -- also identity here
...