Files
sx/examples/147-objc-class-dealloc-roundtrip.sx
agra c107aa4e21 ffi M1.2 A.6: synthesized -dealloc IMP + [super dealloc] chain
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.
2026-05-25 23:25:13 +03:00

62 lines
2.2 KiB
Plaintext

// M1.2 A.6 — synthesized `-dealloc` IMP frees the sx state
// struct and chains to `[super dealloc]` via
// `objc_msgSendSuper2`.
//
// Round-trip:
// 1. [SxFoo alloc] returns a fresh instance with state bound.
// 2. release the instance — runtime invokes our -dealloc IMP.
// 3. Verify the IMP fired: another alloc/release cycle works
// without crashes, and the runtime reports the class
// properly implements -dealloc.
//
// Full instance-state round-trips (sx-side `f := SxFoo.alloc();
// f.bump();`) await A.7's dispatch-gate opening.
#import "modules/std.sx";
#import "modules/compiler.sx";
#import "modules/std/objc.sx";
class_getInstanceVariable :: (cls: *void, name: [*]u8) -> *void #foreign objc;
class_getMethodImplementation :: (cls: *void, sel: *void) -> *void #foreign objc;
SxFoo :: #objc_class("SxFoo") {
counter: s32;
bump :: (self: *Self) {
self.counter += 1;
}
}
main :: () -> s32 {
inline if OS == .macos {
cls : Class = objc_getClass("SxFoo".ptr);
if cls == null { print("FAIL: SxFoo not registered\n"); return 1; }
// Confirm the runtime sees our -dealloc IMP.
sel_dealloc : SEL = sel_registerName("dealloc".ptr);
imp_dealloc : *void = class_getMethodImplementation(cls, sel_dealloc);
if imp_dealloc == null { print("FAIL: dealloc IMP missing\n"); return 1; }
// alloc + release — synthesized -dealloc IMP fires inside.
sel_alloc : SEL = sel_registerName("alloc".ptr);
alloc_fn : (cls: *void, sel: *void) -> *void callconv(.c) = xx objc_msgSend;
instance : *void = alloc_fn(cls, sel_alloc);
if instance == null { print("FAIL: +alloc returned null\n"); return 1; }
sel_release : SEL = sel_registerName("release".ptr);
release_fn : (obj: *void, sel: *void) -> void callconv(.c) = xx objc_msgSend;
release_fn(instance, sel_release);
// Run another cycle to confirm dealloc didn't corrupt runtime state.
instance2 : *void = alloc_fn(cls, sel_alloc);
if instance2 == null { print("FAIL: +alloc round 2 returned null\n"); return 1; }
release_fn(instance2, sel_release);
print("dealloc: ok\n");
}
inline if OS != .macos {
print("dealloc: ok\n");
}
0;
}