Reduce code bloat around declaration chaining

[tanyongkiam]

The stubs for function declarations should be cleaned up to reduce code bloat:

Example from the explorer output:

(func dec@59 ()
   (let
      (a <-
         (op (SetGlobal 3)
            (op (Cons 30) (op (Const 0)) (op (Label fst_clos@424)))))
      (call dec@60)))

(func dec@60 ()
   (let
      (a <-
         (op (SetGlobal 7)
            (op (Cons 30) (op (Const 2)) (op (Label o_clos@426)))))
      (call dec@61)))

These stubs become quite large later:

(dec@246
   (asm (Arith (Binop Sub 12 12 (Imm 0x10))))
   (jump_cmp (Lower 12 (Reg 13)) _Halt2@2 0)
   (label dec@246 1)
   (asm (Mem Load 7 (Addr 13 0xFFFFFFFFFFFFFFD8)))
   (asm (Mem Load 6 (Addr 13 0xFFFFFFFFFFFFFFF8)))
   (asm (Arith (Binop Sub 7 7 (Reg 6))))
   (jump_cmp (NotLower 7 (Imm 0x18)) dec@246 4)
   (asm (Const 7 0x18))
   (asm (Mem Store 0 (Addr 12 0x8)))
   (asm (Const 11 0x161))
   (asm (Mem Store 11 (Addr 12 0x0)))
   (loc_value 0 dec@246 2)
   (jump _GC@4 0)
   (label dec@246 2)
   (asm (Mem Load 0 (Addr 12 0x8)))
   (label dec@246 4)
   (asm (Const 7 0x0))
   (loc_value 2 fst_clos@1341 0)
   (asm (Mem Load 6 (Addr 13 0xFFFFFFFFFFFFFFF8)))
   (asm (Const 1 0x2000001E3))
   (asm (Mem Store 1 (Addr 6 0x0)))
   (asm (Mem Store 2 (Addr 6 0x8)))
   (asm (Mem Store 7 (Addr 6 0x10)))
   (asm (Arith (Binop Or 7 6 (Reg 6))))
   (asm (Arith (Binop Sub 7 7 (Reg 14))))
   (asm (Arith (Shift Lsl 7 7 9)))
   (asm (Arith (Binop Or 7 7 (Imm 0x1E5))))
   (asm (Arith (Binop Add 6 6 (Imm 0x18))))
   (asm (Mem Store 6 (Addr 13 0xFFFFFFFFFFFFFFF8)))
   (asm (Mem Load 6 (Addr 13 0xFFFFFFFFFFFFFFB8)))
   (asm (Mem Store 7 (Addr 6 0x28)))
   (jump dec@249 1)
   (label dec@246 5))

(dec@249
   (asm (Arith (Binop Sub 12 12 (Imm 0x10))))
   (jump_cmp (Lower 12 (Reg 13)) _Halt2@2 0)
   (label dec@249 1)
   (asm (Mem Load 7 (Addr 13 0xFFFFFFFFFFFFFFD8)))
   (asm (Mem Load 6 (Addr 13 0xFFFFFFFFFFFFFFF8)))
   (asm (Arith (Binop Sub 7 7 (Reg 6))))
   (jump_cmp (NotLower 7 (Imm 0x18)) dec@249 4)
   (asm (Const 7 0x18))
   (asm (Mem Store 0 (Addr 12 0x8)))
   (asm (Const 11 0x162))
   (asm (Mem Store 11 (Addr 12 0x0)))
   (loc_value 0 dec@249 2)
   (jump _GC@4 0)
   (label dec@249 2)
   (asm (Mem Load 0 (Addr 12 0x8)))
   (label dec@249 4)
   (asm (Const 7 0x8))
   (loc_value 2 o_clos@1347 0)
   (asm (Mem Load 6 (Addr 13 0xFFFFFFFFFFFFFFF8)))
   (asm (Const 1 0x2000001E3))
   (asm (Mem Store 1 (Addr 6 0x0)))
   (asm (Mem Store 2 (Addr 6 0x8)))
   (asm (Mem Store 7 (Addr 6 0x10)))
   (asm (Arith (Binop Or 7 6 (Reg 6))))
   (asm (Arith (Binop Sub 7 7 (Reg 14))))
   (asm (Arith (Shift Lsl 7 7 9)))
   (asm (Arith (Binop Or 7 7 (Imm 0x1E5))))
   (asm (Arith (Binop Add 6 6 (Imm 0x18))))
   (asm (Mem Store 6 (Addr 13 0xFFFFFFFFFFFFFFF8)))
   (asm (Mem Load 6 (Addr 13 0xFFFFFFFFFFFFFFB8)))
   (asm (Mem Store 7 (Addr 6 0x48)))
   (jump dec@252 1)
   (label dec@249 5))