[ObjC] Add support for removing runtime calls that perform retain count operations

A new activity is added that will remove calls to `objc_retain`,
`objc_release`, `objc_autorelease`, and related functions. It is
disabled by default due to the fact it changes the semantics of the
code. It can be enabled on a per-function basis via the Function
Settings context menu or command palette entry. Alternatively, it can be
enabled in Open with Options or in user settings if a user would prefer
it be on for an entire file or for all files they open.

For now the activity is only eligible within arm64 binaries. Supporting
x86_64 will require matching some slightly different IL patterns.

1 files changed, 19 insertions, 0 deletions

diff --git a/plugins/workflow_objc/src/workflow.rs b/plugins/workflow_objc/src/workflow.rs
index f411951b..f1054411 100644
--- a/plugins/workflow_objc/src/workflow.rs
+++ b/plugins/workflow_objc/src/workflow.rs
@@ -69,9 +69,28 @@ pub fn register_activities() -> Result<(), WorkflowRegistrationError> {
         run(activities::super_init::process),
     );
 
+    let remove_memory_management_activity = Activity::new_with_action(
+        activity::Config::action(
+            "core.function.objectiveC.removeMemoryManagement",
+            "Obj-C: Remove reference counting calls",
+            "Remove calls to objc_retain / objc_release / objc_autorelease to simplify the resulting higher-level ILs",
+        )
+        .eligibility(
+            activity::Eligibility::auto_with_default(false).matching_all_predicates(&[
+                activity::ViewType::in_(["Mach-O", "DSCView"]).into(),
+                activity::Platform::in_(["mac-aarch64", "ios-aarch64"]).into()
+            ])
+        ),
+        run(activities::remove_memory_management::process),
+    );
+
     workflow
         .activity_after(&inline_stubs_activity, "core.function.translateTailCalls")?
         .activity_after(&objc_msg_send_calls_activity, &inline_stubs_activity.name())?
+        .activity_before(
+            &remove_memory_management_activity,
+            "core.function.generateMediumLevelIL",
+        )?
         .activity_after(&super_init_activity, "core.function.generateMediumLevelIL")?
         .register_with_config(WORKFLOW_INFO)?;