Fix FX tracing issues for Llama (#30619)

src/transformers/utils/fx.py

@@ -714,9 +714,14 @@ class HFCacheProxy(HFProxy):
     Proxy that represents an instance of `transformers.cache_utils.Cache`.
     """
 
+    def install_orig_cache_cls(self, orig_cache_cls: Type[Cache]):
+        self._orig_cache_cls = orig_cache_cls
+
     @property
     def __class__(self):
-        return ProxyableCache
+        if not hasattr(self, "_orig_cache_cls"):
+            raise RuntimeError("The original Cache class must be installed to the HFCacheProxy.")
+        return self.tracer._CLASSES_TO_PATCH[self._orig_cache_cls]
 
 
 def create_wrapper(
@@ -806,23 +811,39 @@ def _proxies_to_metas(v):
     return v
 
 
-def cache_proxy_factory_fn(n: Node) -> HFCacheProxy:
+def create_cache_proxy_factory_fn(orig_cache_cls: Type[Cache]) -> Callable[[Node], HFCacheProxy]:
+    def cache_proxy_factory_fn(n: Node) -> HFCacheProxy:
         global _CURRENT_TRACER
         if not isinstance(_CURRENT_TRACER, HFTracer):
             raise RuntimeError("Cannot create HFCacheProxy because there is no HFTracer currently tracing.")
-    return HFCacheProxy(n, _CURRENT_TRACER)
+        cache_proxy = HFCacheProxy(n, _CURRENT_TRACER)
+        cache_proxy.install_orig_cache_cls(orig_cache_cls)
+        return cache_proxy
+
+    return cache_proxy_factory_fn
 
 
 # Proxyable equivalent of the cache classes defined in `transformers.cache_utils`.
-ProxyableCache = HFProxyableClassMeta("ProxyableCache", (Cache,), {}, proxy_factory_fn=cache_proxy_factory_fn)
+ProxyableCache = HFProxyableClassMeta(
+    "ProxyableCache", (Cache,), {}, proxy_factory_fn=create_cache_proxy_factory_fn(Cache)
+)
 ProxyableDynamicCache = HFProxyableClassMeta(
-    "ProxyableDynamicCache", (DynamicCache,), {}, proxy_factory_fn=cache_proxy_factory_fn
+    "ProxyableDynamicCache",
+    (DynamicCache,),
+    {},
+    proxy_factory_fn=create_cache_proxy_factory_fn(DynamicCache),
 )
 ProxyableSinkCache = HFProxyableClassMeta(
-    "ProxyableSinkCache", (SinkCache,), {}, proxy_factory_fn=cache_proxy_factory_fn
+    "ProxyableSinkCache",
+    (SinkCache,),
+    {},
+    proxy_factory_fn=create_cache_proxy_factory_fn(SinkCache),
 )
 ProxyableStaticCache = HFProxyableClassMeta(
-    "ProxyableStaticCache", (StaticCache,), {}, proxy_factory_fn=cache_proxy_factory_fn
+    "ProxyableStaticCache",
+    (StaticCache,),
+    {},
+    proxy_factory_fn=create_cache_proxy_factory_fn(StaticCache),
 )