Automatically emit objc_msgSend calls when calling imported or implemented Objective-C methods

- Add intrinsics.objc_super()

- Emit objc_msgSendSuper2 calls when an objc method call is combined with objc_super(self)

- Fix objc_block return value ABI for large struct returns

- Fix objc_implement method wrappers bad ABI for large struct returns and indirect args

- Simplify parameter forwarding for objc_imlpement methods

- Add intrinsics.objc_instancetype to mimi Objective-C instancetype* returns
  This facilitates returning the correct type on subclasses when calling mehtods
  such as `alloc`, `init`, `retain`, etc.

- Refactor Objective-C class implementations generation so that hierarchies are properly initialized

- Better codegen for context passing with ivar-based autocontext

- Allow @superclass on imported objc-c objects

- Better codegen for block forwarding invoker, arguments are forwarded directly

2 files changed, 18 insertions, 8 deletions

diff --git a/base/intrinsics/intrinsics.odin b/base/intrinsics/intrinsics.odin
index 2d940cf67..dd508180d 100644
--- a/base/intrinsics/intrinsics.odin
+++ b/base/intrinsics/intrinsics.odin
@@ -374,10 +374,11 @@ objc_selector :: struct{}
 objc_class    :: struct{}
 objc_ivar     :: struct{}
 
-objc_id    :: ^objc_object
-objc_SEL   :: ^objc_selector
-objc_Class :: ^objc_class
-objc_Ivar  :: ^objc_ivar
+objc_id           :: ^objc_object
+objc_SEL          :: ^objc_selector
+objc_Class        :: ^objc_class
+objc_Ivar         :: ^objc_ivar
+objc_instancetype :: distinct objc_id
 
 objc_find_selector     :: proc($name: string) -> objc_SEL   ---
 objc_register_selector :: proc($name: string) -> objc_SEL   ---
@@ -385,6 +386,7 @@ objc_find_class        :: proc($name: string) -> objc_Class ---
 objc_register_class    :: proc($name: string) -> objc_Class ---
 objc_ivar_get          :: proc(self: ^$T) -> ^$U ---
 objc_block             :: proc(invoke: $T, ..any) -> ^Objc_Block(T) where type_is_proc(T) ---
+objc_super             :: proc(obj: ^$T) -> ^$U where type_is_subtype_of(T, objc_object) && type_is_subtype_of(U, objc_object) ---
 
 valgrind_client_request :: proc(default: uintptr, request: uintptr, a0, a1, a2, a3, a4: uintptr) -> uintptr ---
 
diff --git a/base/runtime/procs_darwin.odin b/base/runtime/procs_darwin.odin
index d176f0f63..cc3dabc9b 100644
--- a/base/runtime/procs_darwin.odin
+++ b/base/runtime/procs_darwin.odin
@@ -15,16 +15,23 @@ objc_SEL   :: ^intrinsics.objc_selector
 objc_Ivar  :: ^intrinsics.objc_ivar
 objc_BOOL  :: bool
 
+objc_super :: struct {
+	receiver: 	 objc_id,
+	super_class: objc_Class,
+}
 
 objc_IMP :: proc "c" (object: objc_id, sel: objc_SEL, #c_vararg args: ..any) -> objc_id
 
 foreign ObjC {
 	sel_registerName :: proc "c" (name: cstring) -> objc_SEL ---
 
-	objc_msgSend        :: proc "c" (self: objc_id, op: objc_SEL, #c_vararg args: ..any) ---
-	objc_msgSend_fpret  :: proc "c" (self: objc_id, op: objc_SEL, #c_vararg args: ..any) -> f64 ---
-	objc_msgSend_fp2ret :: proc "c" (self: objc_id, op: objc_SEL, #c_vararg args: ..any) -> complex128 ---
-	objc_msgSend_stret  :: proc "c" (self: objc_id, op: objc_SEL, #c_vararg args: ..any) ---
+	objc_msgSend             :: proc "c" (self: objc_id, op: objc_SEL, #c_vararg args: ..any) ---
+	objc_msgSend_fpret       :: proc "c" (self: objc_id, op: objc_SEL, #c_vararg args: ..any) -> f64 ---
+	objc_msgSend_fp2ret      :: proc "c" (self: objc_id, op: objc_SEL, #c_vararg args: ..any) -> complex128 ---
+	objc_msgSend_stret       :: proc "c" (self: objc_id, op: objc_SEL, #c_vararg args: ..any) ---
+	objc_msgSendSuper2       :: proc "c" (super: ^objc_super, op: objc_SEL, #c_vararg args: ..any) ---
+	objc_msgSendSuper2_stret :: proc "c" (super: ^objc_super, op: objc_SEL, #c_vararg args: ..any) ---
+
 
 	objc_lookUpClass          :: proc "c" (name: cstring) -> objc_Class ---
 	objc_allocateClassPair    :: proc "c" (superclass: objc_Class, name: cstring, extraBytes: uint) -> objc_Class ---
@@ -33,6 +40,7 @@ foreign ObjC {
 	class_addIvar             :: proc "c" (cls: objc_Class, name: cstring, size: uint, alignment: u8, types: cstring) -> objc_BOOL ---
 	class_getInstanceVariable :: proc "c" (cls : objc_Class, name: cstring) -> objc_Ivar ---
 	class_getInstanceSize     :: proc "c" (cls : objc_Class) -> uint ---
+	class_getSuperclass       :: proc "c" (cls : objc_Class) -> objc_Class ---
 	ivar_getOffset            :: proc "c" (v: objc_Ivar) -> uintptr ---
 	object_getClass           :: proc "c" (obj: objc_id) -> objc_Class ---
 }