ZJIT: Keep a frame pointer and use it for memory params

Previously, ZJIT miscompiled the following because of native SP
interference.

    def a(n1,n2,n3,n4,n5,n6,n7,n8) = [n8]
    a(0,0,0,0,0,0,0, :ok)

Commented problematic disassembly:

    ; call rb_ary_new_capa
    mov x0, #1
    mov x16, #0x1278
    movk x16, #0x4bc, lsl #16
    movk x16, #1, lsl #32
    blr x16
    ; call rb_ary_push
    mov x1, x0
    str x1, [sp, #-0x10]! ; c_push() from alloc_regs()
    mov x0, x1            ; arg0, the array
    ldur x1, [sp]         ; meant to be arg1=n8, but sp just moved!
    mov x16, #0x3968
    movk x16, #0x4bc, lsl #16
    movk x16, #1, lsl #32
    blr x16

Since the frame pointer stays constant in the body of the function,
static offsets based on it don't run the risk of being invalidated by SP
movements.

Pass the registers to preserve through Insn::FrameSetup. This allows ARM
to use STP and waste no gaps between EC, SP, and CFP.

x86 now preserves and restores RBP since we use it as the frame pointer.
Since all arches now have a frame pointer, remove offset based SP
movement in the epilogue and restore registers using the frame pointer.

0 files changed, 0 insertions, 0 deletions