add "Objective-C Version" LLVM module flag

Author: jbatez

compiler/rustc_codegen_llvm/src/context.rs

@@ -689,7 +689,17 @@ impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> {
     }
 
     pub(crate) fn add_objc_module_flags(&self) {
+        // Darwin-like targets only.
         assert!(self.tcx.sess.target.is_like_darwin);
+        let is_x86_32_macos =
+            self.tcx.sess.target.arch == "x86" && self.tcx.sess.target.os == "macos";
+
+        llvm::add_module_flag_u32(
+            self.llmod,
+            llvm::ModuleFlagMergeBehavior::Error,
+            "Objective-C Version",
+            if is_x86_32_macos { 1 } else { 2 },
+        );
 
         llvm::add_module_flag_u32(
             self.llmod,
@@ -702,7 +712,7 @@ impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> {
             self.llmod,
             llvm::ModuleFlagMergeBehavior::Error,
             "Objective-C Image Info Section",
-            if self.tcx.sess.target.arch == "x86" && self.tcx.sess.target.os == "macos" {
+            if is_x86_32_macos {
                 "__OBJC,__image_info,regular"
             } else {
                 "__DATA,__objc_imageinfo,regular,no_dead_strip"

tests/codegen-llvm/darwin-objc-32bit-x86-macos.rs

@@ -43,6 +43,7 @@ pub fn get_selector() -> *mut () {
 // CHECK: load ptr, ptr @OBJC_CLASS_REFERENCES_.{{[0-9]+}}, align 4
 // CHECK: load ptr, ptr @OBJC_SELECTOR_REFERENCES_.{{[0-9]+}}, align 4
 
+// CHECK: !{{[0-9]+}} = !{i32 1, !"Objective-C Version", i32 1}
 // CHECK: !{{[0-9]+}} = !{i32 1, !"Objective-C Image Info Version", i32 0}
 // CHECK: !{{[0-9]+}} = !{i32 1, !"Objective-C Image Info Section", !"__OBJC,__image_info,regular"}
 // CHECK-NOT: !{{[0-9]+}} = !{i32 1, !"Objective-C Is Simulated", i32 32}

tests/codegen-llvm/darwin-objc.rs

@@ -86,6 +86,7 @@ pub fn get_selector() -> *mut () {
 // aarch64_ios-SAME: align 8
 // aarch64_ios_sim-SAME: align 8
 
+// CHECK: !{{[0-9]+}} = !{i32 1, !"Objective-C Version", i32 2}
 // CHECK: !{{[0-9]+}} = !{i32 1, !"Objective-C Image Info Version", i32 0}
 // CHECK: !{{[0-9]+}} = !{i32 1, !"Objective-C Image Info Section", !"__DATA,__objc_imageinfo,regular,no_dead_strip"}