Merge pull request #4598 from rust-lang/rustup-2025-09-20

Automatic Rustup

1 files changed, 21 insertions, 3 deletions

diff --git a/compiler/rustc_codegen_llvm/src/base.rs b/compiler/rustc_codegen_llvm/src/base.rs
index 9cc5d8dbc21..978134cc32b 100644
--- a/compiler/rustc_codegen_llvm/src/base.rs
+++ b/compiler/rustc_codegen_llvm/src/base.rs
@@ -109,18 +109,36 @@ pub(crate) fn compile_codegen_unit(
                 attributes::apply_to_llfn(entry, llvm::AttributePlace::Function, &attrs);
             }
 
+            // Define Objective-C module info and module flags. Note, the module info will
+            // also be added to the `llvm.compiler.used` variable, created later.
+            //
+            // These are only necessary when we need the linker to do its Objective-C-specific
+            // magic. We could theoretically do it unconditionally, but at a slight cost to linker
+            // performance in the common case where it's unnecessary.
+            if !cx.objc_classrefs.borrow().is_empty() || !cx.objc_selrefs.borrow().is_empty() {
+                if cx.objc_abi_version() == 1 {
+                    cx.define_objc_module_info();
+                }
+                cx.add_objc_module_flags();
+            }
+
             // Finalize code coverage by injecting the coverage map. Note, the coverage map will
             // also be added to the `llvm.compiler.used` variable, created next.
             if cx.sess().instrument_coverage() {
                 cx.coverageinfo_finalize();
             }
 
-            // Create the llvm.used and llvm.compiler.used variables.
+            // Create the llvm.used variable.
             if !cx.used_statics.is_empty() {
                 cx.create_used_variable_impl(c"llvm.used", &cx.used_statics);
             }
-            if !cx.compiler_used_statics.is_empty() {
-                cx.create_used_variable_impl(c"llvm.compiler.used", &cx.compiler_used_statics);
+
+            // Create the llvm.compiler.used variable.
+            {
+                let compiler_used_statics = cx.compiler_used_statics.borrow();
+                if !compiler_used_statics.is_empty() {
+                    cx.create_used_variable_impl(c"llvm.compiler.used", &compiler_used_statics);
+                }
             }
 
             // Run replace-all-uses-with for statics that need it. This must