For every sx-defined #objc_class, emit a C-callconv -dealloc IMP
that runs at refcount-zero. Frees the sx state struct, nils the
ivar, then chains to [super dealloc] so NSObject's runtime
cleanup (object_dispose, associated-object teardown, KVO, etc.)
runs as usual.
-dealloc IMP (self: id, _cmd: SEL) -> void
state = object_getIvar(self, load @__<Cls>_state_ivar)
free(state) // free(NULL) is safe
object_setIvar(self, ivar, NULL)
sup = alloca { receiver: *void, super_class: *void }
sup.receiver = self
sup.super_class = load @__<Cls>_class
sel_dealloc = sel_registerName("dealloc")
objc_msgSendSuper2(&sup, sel_dealloc)
return
Two new per-class globals:
- '__<Cls>_class' : *void — populated by emit_llvm's
class-pair init constructor with the freshly-allocated Class
pointer (after objc_registerClassPair).
- The existing '__<Cls>_state_ivar' is also consulted to find
the state struct.
The -dealloc IMP is registered on the class itself (instance
method) via class_addMethod with encoding 'v@:'. emit_llvm
ALSO stores cls_val into '__<Cls>_class' so the trampoline
can build the objc_super struct.
internStringConstantGlobal helper added to lower.zig — interns
C strings as [N:0]u8 globals with byte-level aggregate inits.
Used here for the 'dealloc' selector string.
147-objc-class-dealloc-roundtrip.sx verifies end-to-end on
macOS: alloc + release fires the IMP, and a second alloc/release
cycle proves runtime state isn't corrupted. class_getMethod-
Implementation confirms the IMP is registered.
176 example tests pass (+1). zig build test green.
Still gated: sx-side 'obj.method()' calls bail at lower.zig:4407
with the existing diagnostic. A.7 opens the gate — last sub-step
of M1.2.
c107aa4e21