Rewrite Obj-C workflow in Rust

This is functionally equivalent to the previous workflow_objc, with the
following changes:
1. It mutates the `core.function.metaAnalysis` workflow rather than
   registering a new named workflow. The activities now all check for
   the presence of the Objective-C metadata added by `ObjCProcessor` to
   determine whether they should do work, rather than relying on
   `MachoView` to override the function workflow when Objective-C
   metadata is present. This fixes
   https://github.com/Vector35/binaryninja-api/issues/6779.
2. The auto-inlining of `objc_msgSend` selector stub functions is
   performed in a separate activity from the processing of
   `objc_msgSend` call sites. The selector stub inlining activity is
   configured so that it does not run in `DSCView` as the shared cache
   needs different behavior for stub functions more generally that
   `SharedCacheWorkflow` already provides.
3. The way that types like `id` and `SEL` are referenced is fixed so
   that they show up as `id` rather than `objc_struct*`.

This also replaces the Objective-C portion of the shared cache's
workflow, and incorporates several bug fixes that had been applied to it
but not the standalone Objective-C workflow.

1 files changed, 57 insertions, 0 deletions

diff --git a/plugins/workflow_objc/src/workflow.rs b/plugins/workflow_objc/src/workflow.rs
new file mode 100644
index 00000000..090a8e5e
--- /dev/null
+++ b/plugins/workflow_objc/src/workflow.rs
@@ -0,0 +1,57 @@
+use binaryninja::workflow::{activity, Activity, AnalysisContext, Workflow};
+
+use crate::{activities, error::WorkflowRegistrationError};
+
+const WORKFLOW_INFO: &str = r#"{
+  "title": "Objective-C",
+  "description": "Enhanced analysis for Objective-C code.",
+  "capabilities": []
+}"#;
+
+fn run<E: std::fmt::Debug>(
+    func: impl Fn(&AnalysisContext) -> Result<(), E>,
+) -> impl Fn(&AnalysisContext) {
+    move |ac| {
+        if let Err(err) = func(ac) {
+            log::debug!("Error occurred while running activity: {err:#x?}");
+        }
+    }
+}
+
+pub fn register_activities() -> Result<(), WorkflowRegistrationError> {
+    let workflow =
+        Workflow::cloned("core.function.metaAnalysis").ok_or(WorkflowRegistrationError)?;
+
+    let objc_msg_send_calls_activity = Activity::new_with_action(
+        activity::Config::action(
+            "core.function.objectiveC.analyzeMessageSends",
+            "Obj-C: Analyze Message Sends",
+            "Analyze inline objc_msgSend calls, including applying call type adjustments and resolving to direct calls (if enabled)",
+        ).eligibility(
+            activity::Eligibility::auto().predicate(
+                activity::ViewType::in_(["Mach-O", "DSCView"]),
+        )),
+        run(activities::objc_msg_send_calls::process),
+    );
+
+    let inline_stubs_activity = Activity::new_with_action(
+        activity::Config::action(
+            "core.function.objectiveC.inlineStubs",
+            "Obj-C: Inline Message Send Stubs",
+            "Inline Objective-C selector stubs, such as _objc_msgSend$foo, into their callers",
+        )
+        .eligibility(
+            activity::Eligibility::without_setting()
+                // The shared cache view does its own inlining of stub functions.
+                .predicate(activity::ViewType::in_(["Mach-O"])),
+        ),
+        run(activities::inline_stubs::process),
+    );
+
+    workflow
+        .activity_after(&inline_stubs_activity, "core.function.translateTailCalls")?
+        .activity_after(&objc_msg_send_calls_activity, &inline_stubs_activity.name())?
+        .register_with_config(WORKFLOW_INFO)?;
+
+    Ok(())
+}