[SharedCache] Fix detection of the class name of categories

The logic for determining the class name of a category did not correctly
handle classes defined in other images in the shared cache. There were
two problems:

1. If the class is defined in another image that is already loaded,
   `ObjCProcessor` has already renamed the symbol from `_OBJC_CLASS_$_`
   to `cls_`. Both forms of symbol name are now handled.

2. If the class is defined in an image that is not yet loaded, no symbol
   name is available. The category's class is now looked up in the
   shared cache symbol table, and the symbol's name is parsed as if it
   were an import symbol.

This fixes almost all cases of "Failed to determine base classname for
category" that I have come across.

Mason Reed: Fixed up to make objective-c processor always consult GetSymbol

1 files changed, 3 insertions, 0 deletions

diff --git a/objectivec/objc.h b/objectivec/objc.h
index 754d8d98..935773c1 100644
--- a/objectivec/objc.h
+++ b/objectivec/objc.h
@@ -324,6 +324,9 @@ namespace BinaryNinja {
 		virtual uint64_t GetObjCRelativeMethodBaseAddress(ObjCReader* reader);
 		virtual void GetRelativeMethod(ObjCReader* reader, method_t& meth);
 		virtual std::shared_ptr<ObjCReader> GetReader() = 0;
+		// Because an objective-c processor might have access to other non-view symbols that we want to retrieve.
+		// By default, this will just get symbol at the address in the view.
+		virtual Ref<Symbol> GetSymbol(uint64_t address);
 
 	public:
 		virtual ~ObjCProcessor() = default;