Rollup merge of #145660 - jbatez:darwin_objc, r=jdonszelmann,madsmtm,tmandry

initial implementation of the darwin_objc unstable feature

Tracking issue: https://github.com/rust-lang/rust/issues/145496

This feature makes it possible to reference Objective-C classes and selectors using the same ABI used by native Objective-C on Apple/Darwin platforms. Without it, Rust code interacting with Objective-C must resort to loading classes and selectors using costly string-based lookups at runtime. With it, these references can be loaded efficiently at dynamic load time.

r? ```@tmandry```

try-job: `*apple*`
try-job: `x86_64-gnu-nopt`

1 files changed, 6 insertions, 0 deletions

diff --git a/compiler/rustc_middle/src/middle/codegen_fn_attrs.rs b/compiler/rustc_middle/src/middle/codegen_fn_attrs.rs
index 8b4503073b0..f0d96c6ac89 100644
--- a/compiler/rustc_middle/src/middle/codegen_fn_attrs.rs
+++ b/compiler/rustc_middle/src/middle/codegen_fn_attrs.rs
@@ -69,6 +69,10 @@ pub struct CodegenFnAttrs {
     /// The `#[patchable_function_entry(...)]` attribute. Indicates how many nops should be around
     /// the function entry.
     pub patchable_function_entry: Option<PatchableFunctionEntry>,
+    /// The `#[rustc_objc_class = "..."]` attribute.
+    pub objc_class: Option<Symbol>,
+    /// The `#[rustc_objc_selector = "..."]` attribute.
+    pub objc_selector: Option<Symbol>,
 }
 
 #[derive(Copy, Clone, Debug, TyEncodable, TyDecodable, HashStable, PartialEq, Eq)]
@@ -185,6 +189,8 @@ impl CodegenFnAttrs {
             instruction_set: None,
             alignment: None,
             patchable_function_entry: None,
+            objc_class: None,
+            objc_selector: None,
         }
     }