Better assembly tests

tests/assembly/test_msg_send_zero_cost/expected/apple-aarch64.s

@@ -0,0 +1,28 @@
+	.section	__TEXT,__text,regular,pure_instructions
+	.globl	_handle
+	.p2align	2
+_handle:
+	b	_objc_msgSend
+
+	.globl	_handle_with_sel
+	.p2align	2
+_handle_with_sel:
+Lloh0:
+	adrp	x8, _SEL_REF@PAGE
+Lloh1:
+	ldr	x1, [x8, _SEL_REF@PAGEOFF]
+	b	_objc_msgSend
+	.loh AdrpLdr	Lloh0, Lloh1
+
+	.section	__TEXT,__const
+	.globl	_SEL
+_SEL:
+	.asciz	"someSelector"
+
+	.section	__DATA,__const
+	.globl	_SEL_REF
+	.p2align	3
+_SEL_REF:
+	.quad	_SEL
+
+.subsections_via_symbols

tests/assembly/test_msg_send_zero_cost/expected/apple-armv7.s

@@ -0,0 +1,30 @@
+	.section	__TEXT,__text,regular,pure_instructions
+	.syntax unified
+	.globl	_handle
+	.p2align	2
+	.code	32
+_handle:
+	b	_objc_msgSend
+
+	.globl	_handle_with_sel
+	.p2align	2
+	.code	32
+_handle_with_sel:
+	movw	r1, :lower16:(_SEL_REF-(LPC1_0+8))
+	movt	r1, :upper16:(_SEL_REF-(LPC1_0+8))
+LPC1_0:
+	ldr	r1, [pc, r1]
+	b	_objc_msgSend
+
+	.section	__TEXT,__const
+	.globl	_SEL
+_SEL:
+	.asciz	"someSelector"
+
+	.section	__DATA,__const
+	.globl	_SEL_REF
+	.p2align	2
+_SEL_REF:
+	.long	_SEL
+
+.subsections_via_symbols

tests/assembly/test_msg_send_zero_cost/expected/apple-armv7s.s

@@ -0,0 +1,36 @@
+	.section	__TEXT,__text,regular,pure_instructions
+	.syntax unified
+	.globl	_handle
+	.p2align	2
+	.code	32
+_handle:
+	push	{r7, lr}
+	mov	r7, sp
+	bl	_objc_msgSend
+	pop	{r7, pc}
+
+	.globl	_handle_with_sel
+	.p2align	2
+	.code	32
+_handle_with_sel:
+	push	{r7, lr}
+	mov	r7, sp
+	movw	r1, :lower16:(_SEL_REF-(LPC1_0+8))
+	movt	r1, :upper16:(_SEL_REF-(LPC1_0+8))
+LPC1_0:
+	ldr	r1, [pc, r1]
+	bl	_objc_msgSend
+	pop	{r7, pc}
+
+	.section	__TEXT,__const
+	.globl	_SEL
+_SEL:
+	.asciz	"someSelector"
+
+	.section	__DATA,__const
+	.globl	_SEL_REF
+	.p2align	2
+_SEL_REF:
+	.long	_SEL
+
+.subsections_via_symbols

tests/assembly/test_msg_send_zero_cost/expected/apple-x86.s

@@ -0,0 +1,39 @@
+	.section	__TEXT,__text,regular,pure_instructions
+	.intel_syntax noprefix
+	.globl	_handle
+	.p2align	4, 0x90
+_handle:
+	push	ebp
+	mov	ebp, esp
+	pop	ebp
+	jmp	_objc_msgSend
+
+	.globl	_handle_with_sel
+	.p2align	4, 0x90
+_handle_with_sel:
+	push	ebp
+	mov	ebp, esp
+	sub	esp, 8
+	call	L1$pb
+L1$pb:
+	pop	eax
+	sub	esp, 8
+	push	dword ptr [eax + _SEL_REF-L1$pb]
+	push	dword ptr [ebp + 8]
+	call	_objc_msgSend
+	add	esp, 24
+	pop	ebp
+	ret
+
+	.section	__TEXT,__const
+	.globl	_SEL
+_SEL:
+	.asciz	"someSelector"
+
+	.section	__DATA,__const
+	.globl	_SEL_REF
+	.p2align	2
+_SEL_REF:
+	.long	_SEL
+
+.subsections_via_symbols

tests/assembly/test_msg_send_zero_cost/expected/apple-x86_64.s

@@ -0,0 +1,31 @@
+	.section	__TEXT,__text,regular,pure_instructions
+	.intel_syntax noprefix
+	.globl	_handle
+	.p2align	4, 0x90
+_handle:
+	push	rbp
+	mov	rbp, rsp
+	pop	rbp
+	jmp	_objc_msgSend
+
+	.globl	_handle_with_sel
+	.p2align	4, 0x90
+_handle_with_sel:
+	push	rbp
+	mov	rbp, rsp
+	mov	rsi, qword ptr [rip + _SEL_REF]
+	pop	rbp
+	jmp	_objc_msgSend
+
+	.section	__TEXT,__const
+	.globl	_SEL
+_SEL:
+	.asciz	"someSelector"
+
+	.section	__DATA,__const
+	.globl	_SEL_REF
+	.p2align	3
+_SEL_REF:
+	.quad	_SEL
+
+.subsections_via_symbols

tests/assembly/test_msg_send_zero_cost/lib.rs

@@ -1,4 +1,6 @@
 //! Test that the inner part of msg_send! is inlined into an objc_msgSend
+use core::mem;
+use core::ptr;
 
 use objc2::runtime::{Object, Sel};
 use objc2::MessageReceiver;
@@ -7,3 +9,19 @@ use objc2::MessageReceiver;
 pub fn handle(obj: &Object, sel: Sel) -> *mut Object {
     unsafe { MessageReceiver::send_message(obj, sel, ()).unwrap() }
 }
+
+// This will definitely not work, but is useful for making the assembly look
+// closer to real-world.
+#[no_mangle]
+static SEL: [u8; 13] = *b"someSelector\0";
+#[no_mangle]
+static SEL_REF: Sel = unsafe { mem::transmute(SEL.as_ptr()) };
+
+fn selector() -> Sel {
+    unsafe { ptr::read_volatile(&SEL_REF) }
+}
+
+#[no_mangle]
+pub fn handle_with_sel(obj: &Object) -> *mut Object {
+    unsafe { MessageReceiver::send_message(obj, selector(), ()).unwrap() }
+}