Statically find msgSend functions on apple devices

This ensures that we don't incur performance overhead for that (though we probably didn't before anyways). This is also more correct since it allows the following: #[repr(transparent)] struct Wrapper { inner: f32, } unsafe impl Encode for Wrapper { const ENCODING: Encoding<'static> = f32::ENCODING; }
madsmtm · Sep 1, 2021 · 5f3fa07 · 5f3fa07
1 parent d857e90
commit 5f3fa07
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Showing 7 changed files with 103 additions and 104 deletions.
diff --git a/objc/src/message/apple/arm.rs b/objc/src/message/apple/arm.rs
@@ -1,8 +1,10 @@
-use core::any::{Any, TypeId};
 use core::mem;
 
+use super::MsgSendFn;
 use crate::runtime::Imp;
+use crate::{Encode, Encoding};
 
+// TODO: C-unwind
 extern "C" {
     fn objc_msgSend();
     fn objc_msgSend_stret();
@@ -11,32 +13,27 @@ extern "C" {
     fn objc_msgSendSuper_stret();
 }
 
-pub fn msg_send_fn<R: Any>() -> Imp {
-    // Double-word sized fundamental data types don't use stret,
-    // but any composite type larger than 4 bytes does.
-    // <http://infocenter.arm.com/help/topic/com.arm.doc.ihi0042e/IHI0042E_aapcs.pdf>
-
-    let type_id = TypeId::of::<R>();
-    if mem::size_of::<R>() <= 4
-        || type_id == TypeId::of::<i64>()
-        || type_id == TypeId::of::<u64>()
-        || type_id == TypeId::of::<f64>()
-    {
-        objc_msgSend
-    } else {
-        objc_msgSend_stret
-    }
-}
-
-pub fn msg_send_super_fn<R: Any>() -> Imp {
-    let type_id = TypeId::of::<R>();
-    if mem::size_of::<R>() <= 4
-        || type_id == TypeId::of::<i64>()
-        || type_id == TypeId::of::<u64>()
-        || type_id == TypeId::of::<f64>()
-    {
-        objc_msgSendSuper
-    } else {
-        objc_msgSendSuper_stret
-    }
+/// Double-word sized fundamental data types don't use stret, but any
+/// composite type larger than 4 bytes does.
+///
+/// <http://infocenter.arm.com/help/topic/com.arm.doc.ihi0042e/IHI0042E_aapcs.pdf>
+impl<T: Encode> MsgSendFn for T {
+    const MSG_SEND: Imp = {
+        if let Encoding::LongLong | Encoding::ULongLong | Encoding::Double = T::ENCODING {
+            objc_msgSend
+        } else if mem::size_of::<T>() <= 4 {
+            objc_msgSend
+        } else {
+            objc_msgSend_stret
+        }
+    };
+    const MSG_SEND_SUPER: Imp = {
+        if let Encoding::LongLong | Encoding::ULongLong | Encoding::Double = T::ENCODING {
+            objc_msgSendSuper
+        } else if mem::size_of::<T>() <= 4 {
+            objc_msgSendSuper
+        } else {
+            objc_msgSendSuper_stret
+        }
+    };
 }
diff --git a/objc/src/message/apple/arm64.rs b/objc/src/message/apple/arm64.rs
@@ -1,18 +1,18 @@
+use super::MsgSendFn;
 use crate::runtime::Imp;
+use crate::Encode;
 
+// TODO: C-unwind
 extern "C" {
     fn objc_msgSend();
 
     fn objc_msgSendSuper();
 }
 
-pub fn msg_send_fn<R>() -> Imp {
-    // stret is not even available in arm64.
-    // <https://twitter.com/gparker/status/378079715824660480>
-
-    objc_msgSend
-}
-
-pub fn msg_send_super_fn<R>() -> Imp {
-    objc_msgSendSuper
+/// `objc_msgSend_stret` is not even available in arm64.
+///
+/// <https://twitter.com/gparker/status/378079715824660480>
+impl<T: Encode> MsgSendFn for T {
+    const MSG_SEND: Imp = objc_msgSend;
+    const MSG_SEND_SUPER: Imp = objc_msgSendSuper;
 }
diff --git a/objc/src/message/apple/mod.rs b/objc/src/message/apple/mod.rs
@@ -1,7 +1,5 @@
-use core::any::Any;
-
-use super::{Message, MessageArguments, MessageError, Super};
-use crate::runtime::{Class, Object, Sel};
+use super::{Encode, Message, MessageArguments, MessageError, Super};
+use crate::runtime::{Class, Imp, Object, Sel};
 
 #[cfg(target_arch = "x86")]
 #[path = "x86.rs"]
@@ -16,16 +14,21 @@ mod arch;
 #[path = "arm64.rs"]
 mod arch;
 
-use self::arch::{msg_send_fn, msg_send_super_fn};
+/// On the above architectures we can statically find the correct method to
+/// call from the return type, by looking at it's `Encode` implementation.
+trait MsgSendFn: Encode {
+    const MSG_SEND: Imp;
+    const MSG_SEND_SUPER: Imp;
+}
 
 pub unsafe fn send_unverified<T, A, R>(obj: *const T, sel: Sel, args: A) -> Result<R, MessageError>
 where
     T: Message,
     A: MessageArguments,
-    R: Any,
+    R: Encode,
 {
     let receiver = obj as *mut T as *mut Object;
-    let msg_send_fn = msg_send_fn::<R>();
+    let msg_send_fn = R::MSG_SEND;
     objc_try!({ A::invoke(msg_send_fn, receiver, sel, args) })
 }
 
@@ -38,13 +41,13 @@ pub unsafe fn send_super_unverified<T, A, R>(
 where
     T: Message,
     A: MessageArguments,
-    R: Any,
+    R: Encode,
 {
     let sup = Super {
         receiver: obj as *mut T as *mut Object,
         superclass,
     };
     let receiver = &sup as *const Super as *mut Object;
-    let msg_send_fn = msg_send_super_fn::<R>();
+    let msg_send_fn = R::MSG_SEND_SUPER;
     objc_try!({ A::invoke(msg_send_fn, receiver, sel, args) })
 }
diff --git a/objc/src/message/apple/x86.rs b/objc/src/message/apple/x86.rs
@@ -1,8 +1,10 @@
-use core::any::{Any, TypeId};
 use core::mem;
 
+use super::MsgSendFn;
 use crate::runtime::Imp;
+use crate::{Encode, Encoding};
 
+// TODO: C-unwind
 extern "C" {
     fn objc_msgSend();
     fn objc_msgSend_fpret();
@@ -12,28 +14,26 @@ extern "C" {
     fn objc_msgSendSuper_stret();
 }
 
-pub fn msg_send_fn<R: Any>() -> Imp {
-    // Structures 1 or 2 bytes in size are placed in EAX.
-    // Structures 4 or 8 bytes in size are placed in: EAX and EDX.
-    // Structures of other sizes are placed at the address supplied by the caller.
-    // <https://developer.apple.com/library/mac/documentation/DeveloperTools/Conceptual/LowLevelABI/130-IA-32_Function_Calling_Conventions/IA32.html>
-
-    let type_id = TypeId::of::<R>();
-    let size = mem::size_of::<R>();
-    if type_id == TypeId::of::<f32>() || type_id == TypeId::of::<f64>() {
-        objc_msgSend_fpret
-    } else if size == 0 || size == 1 || size == 2 || size == 4 || size == 8 {
-        objc_msgSend
-    } else {
-        objc_msgSend_stret
-    }
-}
-
-pub fn msg_send_super_fn<R: Any>() -> Imp {
-    let size = mem::size_of::<R>();
-    if size == 0 || size == 1 || size == 2 || size == 4 || size == 8 {
-        objc_msgSendSuper
-    } else {
-        objc_msgSendSuper_stret
-    }
+/// Structures 1 or 2 bytes in size are placed in EAX.
+/// Structures 4 or 8 bytes in size are placed in: EAX and EDX.
+/// Structures of other sizes are placed at the address supplied by the caller.
+///
+/// <https://developer.apple.com/library/mac/documentation/DeveloperTools/Conceptual/LowLevelABI/130-IA-32_Function_Calling_Conventions/IA32.html>
+impl<T: Encode> MsgSendFn for T {
+    const MSG_SEND: Imp = {
+        if let Encoding::Float | Encoding::Double = T::ENCODING {
+            objc_msgSend_fpret
+        } else if let 0 | 1 | 2 | 4 | 8 = mem::size_of::<T>() {
+            objc_msgSend
+        } else {
+            objc_msgSend_stret
+        }
+    };
+    const MSG_SEND_SUPER: Imp = {
+        if let 0 | 1 | 2 | 4 | 8 = mem::size_of::<T>() {
+            objc_msgSendSuper
+        } else {
+            objc_msgSendSuper_stret
+        }
+    };
 }
diff --git a/objc/src/message/apple/x86_64.rs b/objc/src/message/apple/x86_64.rs
@@ -1,7 +1,10 @@
 use core::mem;
 
+use super::MsgSendFn;
 use crate::runtime::Imp;
+use crate::Encode;
 
+// TODO: C-unwind
 extern "C" {
     fn objc_msgSend();
     fn objc_msgSend_stret();
@@ -10,23 +13,24 @@ extern "C" {
     fn objc_msgSendSuper_stret();
 }
 
-pub fn msg_send_fn<R>() -> Imp {
-    // If the size of an object is larger than two eightbytes, it has class MEMORY.
-    // If the type has class MEMORY, then the caller provides space for the return
-    // value and passes the address of this storage.
-    // <http://people.freebsd.org/~obrien/amd64-elf-abi.pdf>
-
-    if mem::size_of::<R>() <= 16 {
-        objc_msgSend
-    } else {
-        objc_msgSend_stret
-    }
-}
-
-pub fn msg_send_super_fn<R>() -> Imp {
-    if mem::size_of::<R>() <= 16 {
-        objc_msgSendSuper
-    } else {
-        objc_msgSendSuper_stret
-    }
+/// If the size of an object is larger than two eightbytes, it has class
+/// MEMORY. If the type has class MEMORY, then the caller provides space for
+/// the return value and passes the address of this storage.
+///
+/// <http://people.freebsd.org/~obrien/amd64-elf-abi.pdf>
+impl<T: Encode> MsgSendFn for T {
+    const MSG_SEND: Imp = {
+        if mem::size_of::<T>() <= 16 {
+            objc_msgSend
+        } else {
+            objc_msgSend_stret
+        }
+    };
+    const MSG_SEND_SUPER: Imp = {
+        if mem::size_of::<T>() <= 16 {
+            objc_msgSendSuper
+        } else {
+            objc_msgSendSuper_stret
+        }
+    };
 }
diff --git a/objc/src/message/gnustep.rs b/objc/src/message/gnustep.rs
@@ -1,7 +1,6 @@
-use core::any::Any;
 use core::mem;
 
-use super::{Message, MessageArguments, MessageError, Super};
+use super::{Encode, Message, MessageArguments, MessageError, Super};
 use crate::runtime::{Class, Imp, Object, Sel};
 
 extern "C" {
@@ -13,7 +12,7 @@ pub unsafe fn send_unverified<T, A, R>(obj: *const T, sel: Sel, args: A) -> Resu
 where
     T: Message,
     A: MessageArguments,
-    R: Any,
+    R: Encode,
 {
     if obj.is_null() {
         return mem::zeroed();
@@ -33,7 +32,7 @@ pub unsafe fn send_super_unverified<T, A, R>(
 where
     T: Message,
     A: MessageArguments,
-    R: Any,
+    R: Encode,
 {
     let receiver = obj as *mut T as *mut Object;
     let sup = Super {

diff --git a/objc/src/message/mod.rs b/objc/src/message/mod.rs
@@ -1,5 +1,4 @@
 use alloc::string::{String, ToString};
-use core::any::Any;
 use core::fmt;
 use core::mem;
 use std::error::Error;
@@ -80,7 +79,7 @@ pub unsafe trait Message: RefEncode {
     where
         Self: Sized,
         A: MessageArguments + EncodeArguments,
-        R: Any + Encode,
+        R: Encode,
     {
         send_message(self, sel, args)
     }
@@ -128,16 +127,13 @@ pub trait MessageArguments: Sized {
     /// This method is the primitive used when sending messages and should not
     /// be called directly; instead, use the `msg_send!` macro or, in cases
     /// with a dynamic selector, the [`Message::send_message`] method.
-    unsafe fn invoke<R>(imp: Imp, obj: *mut Object, sel: Sel, args: Self) -> R
-    where
-        R: Any;
+    unsafe fn invoke<R>(imp: Imp, obj: *mut Object, sel: Sel, args: Self) -> R;
 }
 
 macro_rules! message_args_impl {
     ($($a:ident : $t:ident),*) => (
         impl<$($t),*> MessageArguments for ($($t,)*) {
-            unsafe fn invoke<R>(imp: Imp, obj: *mut Object, sel: Sel, ($($a,)*): Self) -> R
-                    where R: Any {
+            unsafe fn invoke<R>(imp: Imp, obj: *mut Object, sel: Sel, ($($a,)*): Self) -> R {
                 let imp: unsafe extern fn(*mut Object, Sel $(, $t)*) -> R =
                     mem::transmute(imp);
                 imp(obj, sel $(, $a)*)
@@ -221,7 +217,7 @@ pub unsafe fn send_message<T, A, R>(obj: *const T, sel: Sel, args: A) -> Result<
 where
     T: Message,
     A: MessageArguments + EncodeArguments,
-    R: Any + Encode,
+    R: Encode,
 {
     #[cfg(feature = "verify_message")]
     {
@@ -247,7 +243,7 @@ pub unsafe fn send_super_message<T, A, R>(
 where
     T: Message,
     A: MessageArguments + EncodeArguments,
-    R: Any + Encode,
+    R: Encode,
 {
     #[cfg(feature = "verify_message")]
     {