Slightly improve assembly for init and new message calls

madsmtm · madsmtm · commit 2eff74f6c60b · 2023-11-26T02:34:06.000+01:00
Previously, we were calling `sel!` before the inner expression, which increases stack pressure because the compiler doesn't know it's allowed to defer loading the selector until just before it needs it.
diff --git a/crates/objc2/src/macros/mod.rs b/crates/objc2/src/macros/mod.rs
@@ -1188,9 +1188,12 @@ macro_rules! msg_send_bool {
 #[macro_export]
 macro_rules! msg_send_id {
     [$obj:expr, new $(,)?] => ({
-        let sel = $crate::sel!(new);
         let result;
-        result = <$crate::__macro_helpers::New as $crate::__macro_helpers::MsgSendId<_, _>>::send_message_id($obj, sel, ());
+        result = <$crate::__macro_helpers::New as $crate::__macro_helpers::MsgSendId<_, _>>::send_message_id(
+            $obj,
+            $crate::sel!(new),
+            (),
+        );
         result
     });
     [$obj:expr, alloc $(,)?] => ({
@@ -1199,9 +1202,12 @@ macro_rules! msg_send_id {
         result
     });
     [$obj:expr, init $(,)?] => ({
-        let sel = $crate::sel!(init);
         let result;
-        result = <$crate::__macro_helpers::Init as $crate::__macro_helpers::MsgSendId<_, _>>::send_message_id($obj, sel, ());
+        result = <$crate::__macro_helpers::Init as $crate::__macro_helpers::MsgSendId<_, _>>::send_message_id(
+            $obj,
+            $crate::sel!(init),
+            (),
+        );
         result
     });
     [$obj:expr, $($selector_and_arguments:tt)+] => {
diff --git a/crates/test-assembly/crates/test_declare_class/expected/apple-aarch64.s b/crates/test-assembly/crates/test_declare_class/expected/apple-aarch64.s
@@ -341,19 +341,16 @@ Lloh82:
 	.globl	_get_obj
 	.p2align	2
 _get_obj:
-	stp	x20, x19, [sp, #-32]!
-	stp	x29, x30, [sp, #16]
-	add	x29, sp, #16
+	stp	x29, x30, [sp, #-16]!
+	mov	x29, sp
+	bl	_get_class
 Lloh83:
 	adrp	x8, L_OBJC_SELECTOR_REFERENCES_new@GOTPAGE
 Lloh84:
 	ldr	x8, [x8, L_OBJC_SELECTOR_REFERENCES_new@GOTPAGEOFF]
 Lloh85:
-	ldr	x19, [x8]
-	bl	_get_class
-	mov	x1, x19
-	ldp	x29, x30, [sp, #16]
-	ldp	x20, x19, [sp], #32
+	ldr	x1, [x8]
+	ldp	x29, x30, [sp], #16
 	b	_objc_msgSend
 	.loh AdrpLdrGotLdr	Lloh83, Lloh84, Lloh85
 
diff --git a/crates/test-assembly/crates/test_declare_class/expected/apple-armv7s.s b/crates/test-assembly/crates/test_declare_class/expected/apple-armv7s.s
@@ -302,16 +302,15 @@ LPC3_3:
 	.p2align	2
 	.code	32
 _get_obj:
-	push	{r4, r7, lr}
-	add	r7, sp, #4
-	movw	r0, :lower16:(LL_OBJC_SELECTOR_REFERENCES_new$non_lazy_ptr-(LPC4_0+8))
-	movt	r0, :upper16:(LL_OBJC_SELECTOR_REFERENCES_new$non_lazy_ptr-(LPC4_0+8))
-LPC4_0:
-	ldr	r0, [pc, r0]
-	ldr	r4, [r0]
+	push	{r7, lr}
+	mov	r7, sp
 	bl	_get_class
-	mov	r1, r4
-	pop	{r4, r7, lr}
+	movw	r1, :lower16:(LL_OBJC_SELECTOR_REFERENCES_new$non_lazy_ptr-(LPC4_0+8))
+	movt	r1, :upper16:(LL_OBJC_SELECTOR_REFERENCES_new$non_lazy_ptr-(LPC4_0+8))
+LPC4_0:
+	ldr	r1, [pc, r1]
+	ldr	r1, [r1]
+	pop	{r7, lr}
 	b	_objc_msgSend
 
 	.globl	_access_ivars
diff --git a/crates/test-assembly/crates/test_declare_class/expected/apple-old-x86.s b/crates/test-assembly/crates/test_declare_class/expected/apple-old-x86.s
@@ -260,12 +260,11 @@ _get_obj:
 	push	eax
 	call	L4$pb
 L4$pb:
-	pop	eax
-	mov	eax, dword ptr [eax + LL_OBJC_SELECTOR_REFERENCES_new$non_lazy_ptr-L4$pb]
-	mov	esi, dword ptr [eax]
+	pop	esi
 	call	_get_class
+	mov	ecx, dword ptr [esi + LL_OBJC_SELECTOR_REFERENCES_new$non_lazy_ptr-L4$pb]
 	sub	esp, 8
-	push	esi
+	push	dword ptr [ecx]
 	push	eax
 	call	_objc_msgSend
 	add	esp, 20
diff --git a/crates/test-assembly/crates/test_declare_class/expected/apple-x86.s b/crates/test-assembly/crates/test_declare_class/expected/apple-x86.s
@@ -260,12 +260,11 @@ _get_obj:
 	push	eax
 	call	L4$pb
 L4$pb:
-	pop	eax
-	mov	eax, dword ptr [eax + LL_OBJC_SELECTOR_REFERENCES_new$non_lazy_ptr-L4$pb]
-	mov	esi, dword ptr [eax]
+	pop	esi
 	call	_get_class
+	mov	ecx, dword ptr [esi + LL_OBJC_SELECTOR_REFERENCES_new$non_lazy_ptr-L4$pb]
 	sub	esp, 8
-	push	esi
+	push	dword ptr [ecx]
 	push	eax
 	call	_objc_msgSend
 	add	esp, 20
diff --git a/crates/test-assembly/crates/test_declare_class/expected/apple-x86_64.s b/crates/test-assembly/crates/test_declare_class/expected/apple-x86_64.s
@@ -187,15 +187,10 @@ LBB3_4:
 _get_obj:
 	push	rbp
 	mov	rbp, rsp
-	push	rbx
-	push	rax
-	mov	rax, qword ptr [rip + L_OBJC_SELECTOR_REFERENCES_new@GOTPCREL]
-	mov	rbx, qword ptr [rax]
 	call	_get_class
+	mov	rcx, qword ptr [rip + L_OBJC_SELECTOR_REFERENCES_new@GOTPCREL]
+	mov	rsi, qword ptr [rcx]
 	mov	rdi, rax
-	mov	rsi, rbx
-	add	rsp, 8
-	pop	rbx
 	pop	rbp
 	jmp	_objc_msgSend
 
diff --git a/crates/test-assembly/crates/test_msg_send_static_sel/expected/apple-aarch64.s b/crates/test-assembly/crates/test_msg_send_static_sel/expected/apple-aarch64.s
@@ -15,15 +15,15 @@ _handle_alloc_init:
 	stp	x20, x19, [sp, #-32]!
 	stp	x29, x30, [sp, #16]
 	add	x29, sp, #16
+	bl	_objc_alloc
+	mov	x19, x0
 Lloh2:
 	adrp	x8, L_OBJC_SELECTOR_REFERENCES_init@GOTPAGE
 Lloh3:
 	ldr	x8, [x8, L_OBJC_SELECTOR_REFERENCES_init@GOTPAGEOFF]
 Lloh4:
-	ldr	x19, [x8]
-	bl	_objc_alloc
-	mov	x20, x0
-	mov	x1, x19
+	ldr	x20, [x8]
+	mov	x1, x20
 	bl	_objc_msgSend
 	cbz	x0, LBB1_2
 	ldp	x29, x30, [sp, #16]
@@ -34,8 +34,8 @@ Lloh5:
 	adrp	x2, l_anon.[ID].1@PAGE
 Lloh6:
 	add	x2, x2, l_anon.[ID].1@PAGEOFF
-	mov	x0, x20
-	mov	x1, x19
+	mov	x0, x19
+	mov	x1, x20
 	bl	SYM(<objc2::__macro_helpers::method_family::RetainSemantics<3_u8> as objc2::__macro_helpers::msg_send_id::MsgSendIdFailed>::failed::GENERATED_ID, 0)
 	.loh AdrpLdrGotLdr	Lloh2, Lloh3, Lloh4
 	.loh AdrpAdd	Lloh5, Lloh6
diff --git a/crates/test-assembly/crates/test_msg_send_static_sel/expected/apple-armv7s.s b/crates/test-assembly/crates/test_msg_send_static_sel/expected/apple-armv7s.s
@@ -16,13 +16,13 @@ LPC0_0:
 _handle_alloc_init:
 	push	{r4, r5, r7, lr}
 	add	r7, sp, #8
+	bl	_objc_alloc
 	movw	r1, :lower16:(LL_OBJC_SELECTOR_REFERENCES_init$non_lazy_ptr-(LPC1_0+8))
 	movt	r1, :upper16:(LL_OBJC_SELECTOR_REFERENCES_init$non_lazy_ptr-(LPC1_0+8))
 LPC1_0:
 	ldr	r1, [pc, r1]
-	ldr	r4, [r1]
-	bl	_objc_alloc
 	mov	r5, r0
+	ldr	r4, [r1]
 	mov	r1, r4
 	bl	_objc_msgSend
 	cmp	r0, #0
diff --git a/crates/test-assembly/crates/test_msg_send_static_sel/expected/apple-old-x86.s b/crates/test-assembly/crates/test_msg_send_static_sel/expected/apple-old-x86.s
@@ -28,19 +28,19 @@ _handle_alloc_init:
 	sub	esp, 12
 	call	L1$pb
 L1$pb:
-	pop	ebx
-	mov	eax, dword ptr [ebx + LL_OBJC_SELECTOR_REFERENCES_init$non_lazy_ptr-L1$pb]
-	mov	edi, dword ptr [eax]
-	mov	eax, dword ptr [ebx + LL_OBJC_SELECTOR_REFERENCES_alloc$non_lazy_ptr-L1$pb]
+	pop	edi
+	mov	eax, dword ptr [edi + LL_OBJC_SELECTOR_REFERENCES_alloc$non_lazy_ptr-L1$pb]
 	sub	esp, 8
 	push	dword ptr [eax]
 	push	dword ptr [ebp + 8]
 	call	_objc_msgSend
 	add	esp, 16
 	mov	esi, eax
+	mov	eax, dword ptr [edi + LL_OBJC_SELECTOR_REFERENCES_init$non_lazy_ptr-L1$pb]
+	mov	ebx, dword ptr [eax]
 	sub	esp, 8
-	push	edi
-	push	eax
+	push	ebx
+	push	esi
 	call	_objc_msgSend
 	add	esp, 16
 	test	eax, eax
@@ -53,9 +53,9 @@ L1$pb:
 	ret
 LBB1_2:
 	sub	esp, 4
-	lea	eax, [ebx + l_anon.[ID].1-L1$pb]
+	lea	eax, [edi + l_anon.[ID].1-L1$pb]
 	push	eax
-	push	edi
+	push	ebx
 	push	esi
 	call	SYM(<objc2::__macro_helpers::method_family::RetainSemantics<3_u8> as objc2::__macro_helpers::msg_send_id::MsgSendIdFailed>::failed::GENERATED_ID, 0)
 
diff --git a/crates/test-assembly/crates/test_msg_send_static_sel/expected/apple-x86.s b/crates/test-assembly/crates/test_msg_send_static_sel/expected/apple-x86.s
@@ -28,17 +28,17 @@ _handle_alloc_init:
 	sub	esp, 12
 	call	L1$pb
 L1$pb:
-	pop	ebx
-	mov	eax, dword ptr [ebx + LL_OBJC_SELECTOR_REFERENCES_init$non_lazy_ptr-L1$pb]
-	mov	edi, dword ptr [eax]
+	pop	edi
 	sub	esp, 12
 	push	dword ptr [ebp + 8]
 	call	_objc_alloc
 	add	esp, 16
 	mov	esi, eax
+	mov	eax, dword ptr [edi + LL_OBJC_SELECTOR_REFERENCES_init$non_lazy_ptr-L1$pb]
+	mov	ebx, dword ptr [eax]
 	sub	esp, 8
-	push	edi
-	push	eax
+	push	ebx
+	push	esi
 	call	_objc_msgSend
 	add	esp, 16
 	test	eax, eax
@@ -51,9 +51,9 @@ L1$pb:
 	ret
 LBB1_2:
 	sub	esp, 4
-	lea	eax, [ebx + l_anon.[ID].1-L1$pb]
+	lea	eax, [edi + l_anon.[ID].1-L1$pb]
 	push	eax
-	push	edi
+	push	ebx
 	push	esi
 	call	SYM(<objc2::__macro_helpers::method_family::RetainSemantics<3_u8> as objc2::__macro_helpers::msg_send_id::MsgSendIdFailed>::failed::GENERATED_ID, 0)
 
diff --git a/crates/test-assembly/crates/test_msg_send_static_sel/expected/apple-x86_64.s b/crates/test-assembly/crates/test_msg_send_static_sel/expected/apple-x86_64.s
@@ -16,12 +16,12 @@ _handle_alloc_init:
 	mov	rbp, rsp
 	push	r14
 	push	rbx
-	mov	rax, qword ptr [rip + L_OBJC_SELECTOR_REFERENCES_init@GOTPCREL]
-	mov	rbx, qword ptr [rax]
 	call	_objc_alloc
-	mov	r14, rax
-	mov	rdi, rax
-	mov	rsi, rbx
+	mov	rbx, rax
+	mov	rax, qword ptr [rip + L_OBJC_SELECTOR_REFERENCES_init@GOTPCREL]
+	mov	r14, qword ptr [rax]
+	mov	rdi, rbx
+	mov	rsi, r14
 	call	_objc_msgSend
 	test	rax, rax
 	je	LBB1_2
@@ -31,8 +31,8 @@ _handle_alloc_init:
 	ret
 LBB1_2:
 	lea	rdx, [rip + l_anon.[ID].1]
-	mov	rdi, r14
-	mov	rsi, rbx
+	mov	rdi, rbx
+	mov	rsi, r14
 	call	SYM(<objc2::__macro_helpers::method_family::RetainSemantics<3_u8> as objc2::__macro_helpers::msg_send_id::MsgSendIdFailed>::failed::GENERATED_ID, 0)
 
 	.globl	_use_generic
