Inlining with `getter-with-setter`

[shirok]

If we use getter-with-setter as follows:

(define-inline (foo x) (car x))
(define-inline (foo-set! x v) (set-car! x v))
(define-inline Foo (getter-with-setter foo foo-set!))

Foo is fully inlined:

gosh> (disasm (lambda (x) (Foo x)))
CLOSURE #<closure (#f x)>
=== main_code (name=#f, cc=0x77d9bede3780, codevec=0x77d9bef2e9f0, size=2, const=0 stack=0):
signatureInfo: ((#f x))
     0 LREF0-CAR                ; (car x)
     1 RET 

But if we do this:

(define-inline Foo (getter-with-setter
                    (lambda (x) (car x))
                    (lambda (x v) (set-car! x v))))

It doesn't:

gosh> (disasm (lambda (x) (Foo x)))
CLOSURE #<closure (#f x)>
=== main_code (name=#f, cc=0x77d9bede30c0, codevec=0x77d9be7bb2a0, size=4, const=1 stack=4):
signatureInfo: ((#f x))
     0 LREF0-PUSH               ; x
     1 GREF-TAIL-CALL(1) #<identifier user#Foo.be622100>; (Foo x)
     3 RET 

It's because defining inlinable procedure involves two distinct operations; (1) inset a global binding with 'inlinable' flag, and (2) attach packed IForm to the procedure object, so that the later reference can replace procedure call to its body. With the second example, the compiler failed to do (2).

[shirok]

Inlining globally bound one is addressed in https://github.com/shirok/Gauche/commit/ebcbd534b6ae9e28b4ae2cb2fc052eddfd32a6d1 .

However, locally bound one isn't optimized yet.

(define (foo x)
   (define bar (getter-with-setter (^y (car y)) (^[y v] (set-car y v))))
  ...)

This is uncommon case, but a macro may produce this kind of local definition and it is better to be optimized.

[shirok]

Another, completely different approach that can solve both global and local binding cases.

• Enhance $LAMBDA node to hold setter information (setter's IForm).
• For such $LAMBDA forms, the compiler emits code to attach setter to the resulting closure. In this case we don't need to copy the closure.
• Attach custom inliner to getter-with-setter that translates (getter-with-setter (lambda ...) <setter>) into ($LAMBDA ... (setter <setter-iform>)).
• Then, the existing mechanics of the compiler takes care of the rest.