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, 30 insertions, 0 deletions

diff --git a/plugins/workflow_objc/src/error.rs b/plugins/workflow_objc/src/error.rs
new file mode 100644
index 00000000..75328226
--- /dev/null
+++ b/plugins/workflow_objc/src/error.rs
@@ -0,0 +1,30 @@
+use thiserror::Error;
+
+/// A marker type for workflow registration errors
+#[derive(Debug, Error)]
+#[error("Failed to register workflow activity")]
+pub struct WorkflowRegistrationError;
+
+impl From<()> for WorkflowRegistrationError {
+    fn from(_: ()) -> Self {
+        WorkflowRegistrationError
+    }
+}
+
+#[derive(Error, Debug)]
+pub enum Error {
+    #[error("Unable to retrieve low-level IL for function at {func_start:#x}")]
+    MissingLowLevelIL { func_start: u64 },
+
+    #[error("Unable to retrieve low-level SSA IL for function at {func_start:#x}")]
+    MissingSsaForm { func_start: u64 },
+
+    #[error("Unexpected LLIL operation at address {address:#x} (expected {expected})")]
+    UnexpectedLlilOperation { address: u64, expected: String },
+
+    #[error("Invalid selector at address {address:#x}")]
+    InvalidSelector { address: u64 },
+
+    #[error(transparent)]
+    WorkflowRegistrationFailed(#[from] WorkflowRegistrationError),
+}