Optimize ivar access in declare_class!

madsmtm · Nov 24, 2022 · 1d089e2 · 1d089e2
1 parent 8b54663
commit 1d089e2
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Showing 3 changed files with 76 additions and 34 deletions.
diff --git a/crates/objc2/src/__macro_helpers.rs b/crates/objc2/src/__macro_helpers.rs
@@ -1,17 +1,17 @@
 #[cfg(all(debug_assertions, feature = "verify"))]
 use alloc::vec::Vec;
+use core::cell::Cell;
 use core::ptr;
 #[cfg(all(debug_assertions, feature = "verify"))]
 use std::collections::HashSet;
 
-use crate::declare::ClassBuilder;
-use crate::declare::MethodImplementation;
+use crate::declare::{ClassBuilder, InnerIvarType, IvarType, MethodImplementation};
 use crate::encode::Encode;
 use crate::message::__TupleExtender;
 use crate::rc::{Allocated, Id, Ownership, Shared};
 #[cfg(all(debug_assertions, feature = "verify"))]
 use crate::runtime::MethodDescription;
-use crate::runtime::{Class, Object, Protocol, Sel};
+use crate::runtime::{ivar_offset, Class, Object, Protocol, Sel};
 use crate::{Message, MessageArguments, MessageReceiver};
 use crate::{__sel_data, __sel_inner};
 
@@ -24,8 +24,8 @@ pub use core::convert::{AsMut, AsRef};
 pub use core::mem::size_of;
 pub use core::ops::{Deref, DerefMut};
 pub use core::option::Option::{self, None, Some};
-pub use core::primitive::{bool, str, u8};
-pub use core::ptr::drop_in_place;
+pub use core::primitive::{bool, isize, str, u8};
+pub use core::ptr::{drop_in_place, NonNull};
 pub use core::{compile_error, concat, panic, stringify};
 // TODO: Use `core::cell::LazyCell`
 pub use std::sync::Once;
@@ -632,6 +632,29 @@ impl ClassProtocolMethodsBuilder<'_, '_> {
     }
 }
 
+pub struct IvarStaticHelper {
+    offset: Cell<isize>,
+}
+
+impl IvarStaticHelper {
+    #[inline]
+    pub const fn new() -> Self {
+        Self {
+            offset: Cell::new(0),
+        }
+    }
+
+    pub fn set<T: IvarType>(&self, cls: &Class) {
+        let offset = ivar_offset(cls, T::NAME, &T::Type::__ENCODING);
+        self.offset.set(offset);
+    }
+
+    #[inline]
+    pub fn get(&self) -> isize {
+        self.offset.get()
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

diff --git a/crates/objc2/src/macros/declare_class.rs b/crates/objc2/src/macros/declare_class.rs
@@ -348,9 +348,27 @@ macro_rules! declare_class {
                 __priv: (),
             }
 
+            impl $ivar {
+                #[inline]
+                unsafe fn __offset_ptr() -> &'static $crate::__macro_helpers::IvarStaticHelper {
+                    static mut OFFSET: $crate::__macro_helpers::IvarStaticHelper
+                        = $crate::__macro_helpers::IvarStaticHelper::new();
+                    #[allow(unused_unsafe)]
+                    unsafe { &OFFSET }
+                }
+            }
+
             unsafe impl $crate::declare::IvarType for $ivar {
                 type Type = $ivar_ty;
                 const NAME: &'static str = stringify!($ivar);
+
+                #[inline]
+                unsafe fn __offset(
+                    _ptr: $crate::__macro_helpers::NonNull<$crate::runtime::Object>,
+                ) -> $crate::__macro_helpers::isize {
+                    #[allow(unused_unsafe)]
+                    unsafe { Self::__offset_ptr().get() }
+                }
             }
         )*
 
@@ -424,6 +442,12 @@ macro_rules! declare_class {
                     );
 
                     let _cls = builder.register();
+
+                    $(
+                        unsafe {
+                            $ivar::__offset_ptr().set::<$ivar>(_cls);
+                        }
+                    )*
                 });
 
                 // We just registered the class, so it should be available

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
@@ -548,6 +548,19 @@ LBB9_60:
 LBB9_64:
 	mov	rdi, qword ptr [rbp - 168]
 	call	SYM(objc2::declare::ClassBuilder::register::GENERATED_ID, 0)
+	mov	rbx, rax
+	lea	rsi, [rip + l_anon.[ID].16]
+	lea	rcx, [rip + l_anon.[ID].17]
+	mov	edx, 5
+	mov	rdi, rax
+	call	SYM(objc2::runtime::ivar_offset::GENERATED_ID, 0)
+	mov	qword ptr [rip + SYM(<test_declare_class[CRATE_ID]::ivar1>::__offset_ptr::OFFSET, 0)], rax
+	lea	rsi, [rip + l_anon.[ID].18]
+	lea	rcx, [rip + l_anon.[ID].19]
+	mov	edx, 5
+	mov	rdi, rbx
+	call	SYM(objc2::runtime::ivar_offset::GENERATED_ID, 0)
+	mov	qword ptr [rip + SYM(<test_declare_class[CRATE_ID]::ivar2>::__offset_ptr::OFFSET, 0)], rax
 	add	rsp, 184
 	pop	rbx
 	pop	r12
@@ -1196,29 +1209,12 @@ LBB22_2:
 _access:
 	push	rbp
 	mov	rbp, rsp
-	push	r14
-	push	rbx
 	call	_get_obj
-	mov	rbx, rax
-	mov	rdi, rax
-	call	SYM(objc2::runtime::Object::class::GENERATED_ID, 0)
-	lea	rsi, [rip + l_anon.[ID].16]
-	lea	rcx, [rip + l_anon.[ID].17]
-	mov	edx, 5
-	mov	rdi, rax
-	call	SYM(objc2::runtime::ivar_offset::GENERATED_ID, 0)
-	movzx	r14d, byte ptr [rbx + rax]
-	mov	rdi, rbx
-	call	SYM(objc2::runtime::Object::class::GENERATED_ID, 0)
-	lea	rsi, [rip + l_anon.[ID].18]
-	lea	rcx, [rip + l_anon.[ID].19]
-	mov	edx, 5
-	mov	rdi, rax
-	call	SYM(objc2::runtime::ivar_offset::GENERATED_ID, 0)
-	mov	rdx, qword ptr [rbx + rax]
-	mov	eax, r14d
-	pop	rbx
-	pop	r14
+	mov	rcx, qword ptr [rip + SYM(<test_declare_class[CRATE_ID]::ivar1>::__offset_ptr::OFFSET, 0)]
+	movzx	ecx, byte ptr [rax + rcx]
+	mov	rdx, qword ptr [rip + SYM(<test_declare_class[CRATE_ID]::ivar2>::__offset_ptr::OFFSET, 0)]
+	mov	rdx, qword ptr [rax + rdx]
+	mov	eax, ecx
 	pop	rbp
 	ret
 
@@ -1266,13 +1262,8 @@ SYM(<test_declare_class[CRATE_ID]::Custom>::__objc2_dealloc, 0):
 	push	rbx
 	sub	rsp, 72
 	mov	r14, rdi
-	call	SYM(objc2::runtime::Object::class::GENERATED_ID, 0)
-	lea	rsi, [rip + l_anon.[ID].18]
-	lea	rcx, [rip + l_anon.[ID].19]
-	mov	edx, 5
-	mov	rdi, rax
-	call	SYM(objc2::runtime::ivar_offset::GENERATED_ID, 0)
-	mov	rdi, qword ptr [r14 + rax]
+	mov	rax, qword ptr [rip + SYM(<test_declare_class[CRATE_ID]::ivar2>::__offset_ptr::OFFSET, 0)]
+	mov	rdi, qword ptr [rdi + rax]
 	test	rdi, rdi
 	je	LBB25_2
 	call	_objc_release
@@ -1603,6 +1594,10 @@ L_anon.[ID].49:
 l_anon.[ID].50:
 	.ascii	"crates/$DIR/lib.rs"
 
+	.globl	SYM(<test_declare_class[CRATE_ID]::ivar1>::__offset_ptr::OFFSET, 0)
+.zerofill __DATA,__common,SYM(<test_declare_class[CRATE_ID]::ivar1>::__offset_ptr::OFFSET, 0),8,3
+	.globl	SYM(<test_declare_class[CRATE_ID]::ivar2>::__offset_ptr::OFFSET, 0)
+.zerofill __DATA,__common,SYM(<test_declare_class[CRATE_ID]::ivar2>::__offset_ptr::OFFSET, 0),8,3
 	.section	__DATA,__const
 	.p2align	3
 l_anon.[ID].51: