lab/sx
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

ffi M1.2 A.4b.i: __sx_state ivar registration

Browse Source 
Class-pair init constructor now registers a single hidden ivar
on each sx-defined class:

  class_addIvar(cls, "__sx_state", 8, 3, "^v")

before objc_registerClassPair. After the class is registered,
the constructor calls class_getInstanceVariable to fetch the
runtime Ivar handle and stores it in a per-class global
'__<ClassName>_state_ivar : *void'. Trampolines (A.4b.ii) will
read this global to 'object_getIvar' the state struct pointer.

lower.zig declares the per-class global at scan time
(declareObjcDefinedStateIvarGlobal) so emit_llvm finds it by
name when populating. Encoding '^v' = void* (a generic pointer
— the runtime treats it as opaque storage). log2 alignment = 3
for 8-byte pointer alignment on 64-bit.

144-objc-class-ivar-registration.sx exercises the round-trip:
after main starts, class_getInstanceVariable(SxFoo, "__sx_state")
returns non-null. Runs against the real Obj-C runtime on macOS.

142's IR snapshot refreshed to include the new constructor body
(class_addIvar + class_getInstanceVariable + ivar-global store).

173 example tests pass (+1 from 144). zig build test green.
This commit is contained in:
agra
2026-05-25 22:23:59 +03:00
parent b98a22e3f9
commit c2178c062b
6 changed files with 124 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
tests/expected/142-objc-class-method-lowering.ir
View File

@@ -2,6 +2,7 @@
@OS = internal global i64 0
@ARCH = internal global i64 0
@POINTER_SIZE = internal global i64 8
@__SxFoo_state_ivar = internal global ptr null
@__sx_default_context = internal global { { ptr, ptr, ptr }, ptr } { { ptr, ptr, ptr } { ptr null, ptr @__thunk_CAllocator_Allocator_alloc, ptr @__thunk_CAllocator_Allocator_dealloc }, ptr null }
@str = private unnamed_addr constant [2 x i8] c"0\00", align 1
@str.1 = private unnamed_addr constant [15 x i8] c"result := \22\22; \00", align 1
@@ -22,6 +23,8 @@
@str.16 = private unnamed_addr constant [10 x i8] c"compiled\0A\00", align 1
@str.17 = private unnamed_addr constant [1 x i8] zeroinitializer, align 1
@str.18 = private unnamed_addr constant [10 x i8] c"compiled\0A\00", align 1
@OBJC_IVAR_NAME_ = private unnamed_addr constant [11 x i8] c"__sx_state\00"
@OBJC_IVAR_TYPE_ = private unnamed_addr constant [3 x i8] c"^v\00"
@OBJC_CLASS_NAME_ = private unnamed_addr constant [9 x i8] c"NSObject\00"
@OBJC_CLASS_NAME_.19 = private unnamed_addr constant [6 x i8] c"SxFoo\00"
@llvm.global_ctors = appending global [1 x { i32, ptr, ptr }] [{ i32, ptr, ptr } { i32 65535, ptr @__sx_objc_defined_class_init, ptr null }]
@@ -787,12 +790,19 @@ declare ptr @objc_getClass(ptr)
declare ptr @objc_allocateClassPair(ptr, ptr, i64)
declare i8 @class_addIvar(ptr, ptr, i64, i8, ptr)
declare void @objc_registerClassPair(ptr)
declare ptr @class_getInstanceVariable(ptr, ptr)
define internal void @__sx_objc_defined_class_init() {
entry:
%super_cls = call ptr @objc_getClass(ptr @OBJC_CLASS_NAME_)
%cls = call ptr @objc_allocateClassPair(ptr %super_cls, ptr @OBJC_CLASS_NAME_.19, i64 0)
%0 = call i8 @class_addIvar(ptr %cls, ptr @OBJC_IVAR_NAME_, i64 8, i8 3, ptr @OBJC_IVAR_TYPE_)
call void @objc_registerClassPair(ptr %cls)
%iv = call ptr @class_getInstanceVariable(ptr %cls, ptr @OBJC_IVAR_NAME_)
store ptr %iv, ptr @__SxFoo_state_ivar, align 8
ret void
}

1
tests/expected/144-objc-class-ivar-registration.exit Normal file
View File

@@ -0,0 +1 @@
0

1
tests/expected/144-objc-class-ivar-registration.txt Normal file
View File

@@ -0,0 +1 @@
ivar: __sx_state