Pre-compute and cache MonoClass name hash (#100847)

During startup we spend a measurable amount of time hashing types, and some of that time is spent hashing classnames over and over again, so this PR caches the hash at class creation time instead.

Author: kg

src/mono/mono/metadata/class-getters.h

@@ -56,6 +56,7 @@ MONO_CLASS_GETTER(m_class_get_parent, MonoClass *, , MonoClass, parent)
 MONO_CLASS_GETTER(m_class_get_nested_in, MonoClass *, ,  MonoClass, nested_in)
 MONO_CLASS_GETTER(m_class_get_image, MonoImage *, , MonoClass, image)
 MONO_CLASS_GETTER(m_class_get_name, const char *, , MonoClass, name)
+MONO_CLASS_GETTER(m_class_get_name_hash, guint, , MonoClass, name_hash)
 MONO_CLASS_GETTER(m_class_get_name_space, const char *, , MonoClass, name_space)
 MONO_CLASS_GETTER(m_class_get_type_token, guint32, , MonoClass, type_token)
 MONO_CLASS_GETTER(m_class_get_vtable_size, int, , MonoClass, vtable_size)

src/mono/mono/metadata/class-init.c

@@ -500,6 +500,7 @@ mono_class_create_from_typedef (MonoImage *image, guint32 type_token, MonoError
 	}
 
 	klass->name = name;
+	klass->name_hash = mono_metadata_str_hash (name);
 	klass->name_space = nspace;
 
 	MONO_PROFILER_RAISE (class_loading, (klass));
@@ -909,6 +910,7 @@ mono_class_create_generic_inst (MonoGenericClass *gclass)
 	}
 
 	klass->name = gklass->name;
+	klass->name_hash = gklass->name_hash;
 	klass->name_space = gklass->name_space;
 
 	klass->image = gklass->image;
@@ -1154,6 +1156,7 @@ mono_class_create_bounded_array (MonoClass *eclass, guint32 rank, gboolean bound
 	name [nsize + maxrank + bounded] = ']';
 	name [nsize + maxrank + bounded + 1] = 0;
 	klass->name = mm ? mono_mem_manager_strdup (mm, name) : mono_image_strdup (image, name);
+	klass->name_hash = mono_metadata_str_hash (klass->name);
 	g_free (name);
 
 	klass->type_token = 0;
@@ -1508,6 +1511,7 @@ mono_class_create_ptr (MonoType *type)
 	result->name_space = el_class->name_space;
 	name = g_strdup_printf ("%s*", el_class->name);
 	result->name = mm ? mono_mem_manager_strdup (mm, name) : mono_image_strdup (image, name);
+	result->name_hash = mono_metadata_str_hash (result->name);
 	result->class_kind = MONO_CLASS_POINTER;
 	g_free (name);
 
@@ -1585,6 +1589,7 @@ mono_class_create_fnptr (MonoMethodSignature *sig)
 	result->parent = NULL; /* no parent for PTR types */
 	result->name_space = "System";
 	result->name = "MonoFNPtrFakeClass";
+	result->name_hash = mono_metadata_str_hash (result->name);
 	result->class_kind = MONO_CLASS_POINTER;
 
 	result->image = mono_defaults.corlib; /* need to fix... */

src/mono/mono/metadata/class-private-definition.h

@@ -99,7 +99,8 @@ struct _MonoClass {
 	guint16    *interface_offsets_packed;
 	guint8     *interface_bitmap;
 
-	gint32 inlinearray_value; /* System.Runtime.CompilerServices.InlineArrayAttribute length value */
+	gint32      inlinearray_value; /* System.Runtime.CompilerServices.InlineArrayAttribute length value */
+	guint       name_hash;
 
 	MonoClass **interfaces;
 

src/mono/mono/metadata/metadata.c

@@ -1931,7 +1931,7 @@ static guint
 mono_generic_class_hash (gconstpointer data)
 {
 	const MonoGenericClass *gclass = (const MonoGenericClass *) data;
-	guint hash = mono_metadata_str_hash (m_class_get_name (gclass->container_class));
+	guint hash = m_class_get_name_hash (gclass->container_class);
 
 	hash *= 13;
 	hash += gclass->is_tb_open;
@@ -5611,8 +5611,8 @@ mono_metadata_type_hash (MonoType *t1)
 		 * inserted in a bunch of hash tables before been finished.
 		 */
 		if (image_is_dynamic (m_class_get_image (klass)))
-			return ((m_type_is_byref (t1) ? 1 : 0) << 6) | mono_metadata_str_hash (m_class_get_name (klass));
-		return ((hash << 5) - hash) ^ mono_metadata_str_hash (m_class_get_name (klass));
+			return ((m_type_is_byref (t1) ? 1 : 0) << 6) | m_class_get_name_hash (klass);
+		return ((hash << 5) - hash) ^ m_class_get_name_hash (klass);
 	}
 	case MONO_TYPE_PTR:
 		return ((hash << 5) - hash) ^ mono_metadata_type_hash (t1->data.type);

src/mono/mono/metadata/object.c

@@ -1343,7 +1343,7 @@ mono_method_get_imt_slot (MonoMethod *method)
 	}
 
 	/* Initialize hashes */
-	hashes [0] = mono_metadata_str_hash (m_class_get_name (method->klass));
+	hashes [0] = m_class_get_name_hash (method->klass);
 	hashes [1] = mono_metadata_str_hash (m_class_get_name_space (method->klass));
 	hashes [2] = mono_metadata_str_hash (method->name);
 	hashes [3] = mono_metadata_type_hash (sig->ret);

src/mono/mono/mini/aot-compiler.c

@@ -11181,7 +11181,7 @@ mono_aot_type_hash (MonoType *t1)
 	case MONO_TYPE_CLASS:
 	case MONO_TYPE_SZARRAY:
 		/* check if the distribution is good enough */
-		return ((hash << 5) - hash) ^ mono_metadata_str_hash (m_class_get_name (t1->data.klass));
+		return ((hash << 5) - hash) ^ m_class_get_name_hash (t1->data.klass);
 	case MONO_TYPE_PTR:
 		return ((hash << 5) - hash) ^ mono_metadata_type_hash (t1->data.type);
 	case MONO_TYPE_ARRAY:
@@ -11251,7 +11251,7 @@ mono_aot_method_hash (MonoMethod *method)
 		hashes [1] = 0;
 		g_free (full_name);
 	} else {
-		hashes [0] = mono_metadata_str_hash (m_class_get_name (klass));
+		hashes [0] = m_class_get_name_hash (klass);
 		hashes [1] = mono_metadata_str_hash (m_class_get_name_space (klass));
 	}
 	if (method->wrapper_type == MONO_WRAPPER_MANAGED_TO_NATIVE && mono_marshal_get_wrapper_info (method)->subtype == WRAPPER_SUBTYPE_ICALL_WRAPPER)