[mono][debugger] Support new hot reload features from runtime (#70697)

* Support new hotreload features on mobile devices.

* Implementing support to add methods in hotreload on mobile devices

* Only invalidate code when we really have some change.

* Remove printf

* add/remove extra lines in eof

* Sharing string between the debugger and the managed get capabilities API

src/mono/System.Private.CoreLib/src/System/Reflection/Metadata/MetadataUpdater.cs

@@ -55,13 +55,16 @@ public static void ApplyUpdate(Assembly assembly, ReadOnlySpan<byte> metadataDel
 
         private static string InitializeApplyUpdateCapabilities()
         {
-            const string caps = "Baseline AddMethodToExistingType AddStaticFieldToExistingType NewTypeDefinition";
-            return ApplyUpdateEnabled(justComponentCheck: 1) != 0 ? caps : string.Empty ;
+            string caps = GetApplyUpdateCapabilities();
+            return ApplyUpdateEnabled(justComponentCheck: 1) != 0 ? caps : string.Empty;
         }
 
         [MethodImpl (MethodImplOptions.InternalCall)]
         private static extern int ApplyUpdateEnabled (int justComponentCheck);
 
+        [MethodImpl (MethodImplOptions.InternalCall)]
+        private static extern string GetApplyUpdateCapabilities();
+
         [MethodImpl (MethodImplOptions.InternalCall)]
         private static extern unsafe void ApplyUpdate_internal (IntPtr base_assm, byte* dmeta_bytes, int dmeta_length, byte *dil_bytes, int dil_length, byte *dpdb_bytes, int dpdb_length);
     }

src/mono/mono/component/debugger-agent.c

@@ -7051,6 +7051,10 @@ vm_commands (int command, int id, guint8 *p, guint8 *end, Buffer *buf)
 		buffer_add_moduleid (buf, mono_get_root_domain (), assembly->image);
 		break;
 	}
+	case MDBGPROT_CMD_GET_ENC_CAPABILITIES: {
+		buffer_add_string (buf, mono_enc_capabilities ());
+		break;
+	}
 	default:
 		return ERR_NOT_IMPLEMENTED;
 	}

src/mono/mono/component/debugger-protocol.h

@@ -38,6 +38,7 @@ typedef enum {
 	MDBGPROT_CMD_GET_ASSEMBLY_BY_NAME = 18,
 	MDBGPROT_CMD_GET_MODULE_BY_GUID = 19,
 	MDBGPROT_CMD_GET_ASSEMBLY_BYTES = 20, //wasm specific
+	MDBGPROT_CMD_GET_ENC_CAPABILITIES = 21
 } MdbgProtCmdVM;
 
 typedef enum {

src/mono/mono/component/hot_reload-stub.c

@@ -104,6 +104,12 @@ hot_reload_stub_added_fields_iter (MonoClass *klass, gboolean lazy, gpointer *it
 static uint32_t
 hot_reload_get_num_fields_added (MonoClass *klass);
 
+static uint32_t
+hot_reload_get_num_methods_added (MonoClass *klass);
+
+static const char *
+hot_reload_get_capabilities (void);
+
 static MonoComponentHotReload fn_table = {
 	{ MONO_COMPONENT_ITF_VERSION, &hot_reload_stub_available },
 	&hot_reload_stub_set_fastpath_data,
@@ -134,7 +140,9 @@ static MonoComponentHotReload fn_table = {
 	&hot_reload_stub_get_typedef_skeleton_events,
 	&hot_reload_stub_added_methods_iter,
 	&hot_reload_stub_added_fields_iter,
-	&hot_reload_get_num_fields_added
+	&hot_reload_get_num_fields_added,
+	&hot_reload_get_num_methods_added,
+	&hot_reload_get_capabilities
 };
 
 static bool
@@ -323,6 +331,17 @@ hot_reload_get_num_fields_added (MonoClass *klass)
 	return 0;
 }
 
+static uint32_t
+hot_reload_get_num_methods_added (MonoClass *klass)
+{
+	return 0;
+}
+
+static const char *
+hot_reload_get_capabilities (void)
+{
+	return "";
+}
 
 MONO_COMPONENT_EXPORT_ENTRYPOINT
 MonoComponentHotReload *

src/mono/mono/component/hot_reload.c

@@ -138,6 +138,12 @@ hot_reload_added_fields_iter (MonoClass *klass, gboolean lazy, gpointer *iter);
 static uint32_t
 hot_reload_get_num_fields_added (MonoClass *klass);
 
+static uint32_t
+hot_reload_get_num_methods_added (MonoClass *klass);
+
+static const char *
+hot_reload_get_capabilities (void);
+
 static MonoClassMetadataUpdateField *
 metadata_update_field_setup_basic_info_and_resolve (MonoImage *image_base, BaselineInfo *base_info, uint32_t generation, DeltaInfo *delta_info, MonoClass *parent_klass, uint32_t fielddef_token, uint32_t field_flags, MonoError *error);
 
@@ -172,6 +178,8 @@ static MonoComponentHotReload fn_table = {
 	&hot_reload_added_methods_iter,
 	&hot_reload_added_fields_iter,
 	&hot_reload_get_num_fields_added,
+	&hot_reload_get_num_methods_added,
+	&hot_reload_get_capabilities
 };
 
 MonoComponentHotReload *
@@ -738,11 +746,12 @@ hot_reload_wait_for_update (uint32_t timeout_ms)
 }
 
 static void
-hot_reload_update_publish (MonoAssemblyLoadContext *alc, uint32_t generation)
+hot_reload_update_publish (MonoAssemblyLoadContext *alc, uint32_t generation, gboolean should_invalidate_transformed_code)
 {
 	g_assert (update_published < generation && generation <= update_alloc_frontier);
 	/* TODO: wait for all threads that are using old metadata to update. */
-	hot_reload_update_published_invoke_hook (alc, generation);
+	if (should_invalidate_transformed_code)
+		hot_reload_update_published_invoke_hook (alc, generation);
 	update_published = update_alloc_frontier;
 	mono_memory_write_barrier ();
 	publish_unlock ();
@@ -1374,8 +1383,9 @@ prepare_mutated_rows (const MonoTableInfo *table_enclog, MonoImage *image_base,
  * function will fail and the metadata update should be aborted. This should
  * run before anything in the metadata world is updated. */
 static gboolean
-apply_enclog_pass1 (MonoImage *image_base, MonoImage *image_dmeta, DeltaInfo *delta_info, gconstpointer dil_data, uint32_t dil_length, MonoError *error)
+apply_enclog_pass1 (MonoImage *image_base, MonoImage *image_dmeta, DeltaInfo *delta_info, gconstpointer dil_data, uint32_t dil_length, gboolean *should_invalidate_transformed_code, MonoError *error)
 {
+	*should_invalidate_transformed_code = false;
 	MonoTableInfo *table_enclog = &image_dmeta->tables [MONO_TABLE_ENCLOG];
 	guint32 rows = table_info_get_rows (table_enclog);
 
@@ -1432,6 +1442,7 @@ apply_enclog_pass1 (MonoImage *image_base, MonoImage *image_dmeta, DeltaInfo *de
 			/* okay, supported */
 			break;
 		case MONO_TABLE_METHOD:
+			*should_invalidate_transformed_code = true;
 			if (func_code == ENC_FUNC_ADD_PARAM)
 				continue; /* ok, allowed */
 			/* handled above */
@@ -1441,6 +1452,7 @@ apply_enclog_pass1 (MonoImage *image_base, MonoImage *image_dmeta, DeltaInfo *de
 			g_assert (func_code == ENC_FUNC_DEFAULT);
 			break;
 		case MONO_TABLE_PROPERTYMAP: {
+			*should_invalidate_transformed_code = true;
 			if (func_code == ENC_FUNC_ADD_PROPERTY) {
 				g_assert (i + 1 < rows);
 				i++; /* skip the next record */
@@ -1457,10 +1469,12 @@ apply_enclog_pass1 (MonoImage *image_base, MonoImage *image_dmeta, DeltaInfo *de
 		}
 		case MONO_TABLE_PROPERTY: {
 			/* ok */
+			*should_invalidate_transformed_code = true;
 			g_assert (func_code == ENC_FUNC_DEFAULT);
 			break;
 		}
 		case MONO_TABLE_EVENTMAP: {
+			*should_invalidate_transformed_code = true;
 			if (func_code == ENC_FUNC_ADD_EVENT) {
 				g_assert (i + 1 < rows);
 				i++; /* skip the next record */
@@ -1476,6 +1490,7 @@ apply_enclog_pass1 (MonoImage *image_base, MonoImage *image_dmeta, DeltaInfo *de
 			break;
 		}
 		case MONO_TABLE_METHODSEMANTICS: {
+			*should_invalidate_transformed_code = true;
 			if (is_addition) {
 				/* new rows are fine */
 				break;
@@ -1487,6 +1502,7 @@ apply_enclog_pass1 (MonoImage *image_base, MonoImage *image_dmeta, DeltaInfo *de
 			}
 		}
 		case MONO_TABLE_CUSTOMATTRIBUTE: {
+			*should_invalidate_transformed_code = true;
 			if (!is_addition) {
 				/* modifying existing rows is ok, as long as the parent and ctor are the same */
 				guint32 ca_upd_cols [MONO_CUSTOM_ATTR_SIZE];
@@ -1532,6 +1548,7 @@ apply_enclog_pass1 (MonoImage *image_base, MonoImage *image_dmeta, DeltaInfo *de
 			}
 		}
 		case MONO_TABLE_PARAM: {
+			*should_invalidate_transformed_code = true;
 			if (!is_addition) {
 				/* We only allow modifications where the parameter name doesn't change. */
 				uint32_t base_param [MONO_PARAM_SIZE];
@@ -1557,6 +1574,7 @@ apply_enclog_pass1 (MonoImage *image_base, MonoImage *image_dmeta, DeltaInfo *de
 				break; /* added a row. ok */
 		}
 		case MONO_TABLE_TYPEDEF: {
+			*should_invalidate_transformed_code = true;
 			if (func_code == ENC_FUNC_ADD_METHOD) {
 				/* next record should be a MONO_TABLE_METHOD addition (func == default) */
 				g_assert (i + 1 < rows);
@@ -2503,8 +2521,8 @@ hot_reload_apply_changes (int origin, MonoImage *image_base, gconstpointer dmeta
 
 	mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_METADATA_UPDATE, "Populated mutated tables for delta image %p", image_dmeta);
 
-
-	if (!apply_enclog_pass1 (image_base, image_dmeta, delta_info, dil_bytes, dil_length, error)) {
+	gboolean should_invalidate_transformed_code = false;
+	if (!apply_enclog_pass1 (image_base, image_dmeta, delta_info, dil_bytes, dil_length, &should_invalidate_transformed_code, error)) {
 		mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_METADATA_UPDATE, "Error on sanity-checking delta image to base=%s, due to: %s", basename, mono_error_get_message (error));
 		hot_reload_update_cancel (generation);
 		return;
@@ -2532,7 +2550,7 @@ hot_reload_apply_changes (int origin, MonoImage *image_base, gconstpointer dmeta
 	pass2_context_destroy (&pass2ctx);
 
 	MonoAssemblyLoadContext *alc = mono_image_get_alc (image_base);
-	hot_reload_update_publish (alc, generation);
+	hot_reload_update_publish (alc, generation, should_invalidate_transformed_code);
 
 	mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_METADATA_UPDATE, ">>> EnC delta for base=%s (generation %d) applied", basename, generation);
 }
@@ -3112,3 +3130,23 @@ hot_reload_get_num_fields_added (MonoClass *klass)
 		return 0;
 	return g_slist_length (info->added_fields);
 }
+
+static uint32_t
+hot_reload_get_num_methods_added (MonoClass *klass)
+{
+	uint32_t count = 0;
+	GSList *members = hot_reload_get_added_members (klass);
+	for (GSList *ptr = members; ptr; ptr = ptr->next) {
+		uint32_t token = GPOINTER_TO_UINT(ptr->data);
+		if (mono_metadata_token_table (token) != MONO_TABLE_METHOD)
+			continue;
+		count++;
+	}
+	return count;
+}
+
+static const char *
+hot_reload_get_capabilities (void)
+{
+	return "Baseline AddMethodToExistingType AddStaticFieldToExistingType NewTypeDefinition ChangeCustomAttributes";
+}

src/mono/mono/component/hot_reload.h

@@ -46,6 +46,8 @@ typedef struct _MonoComponentHotReload {
 	MonoMethod* (*added_methods_iter) (MonoClass *klass, gpointer *iter);
 	MonoClassField* (*added_fields_iter) (MonoClass *klass, gboolean lazy, gpointer *iter);
 	uint32_t (*get_num_fields_added) (MonoClass *klass);
+	uint32_t (*get_num_methods_added) (MonoClass *klass);
+	const char* (*get_capabilities) (void);
 } MonoComponentHotReload;
 
 MONO_COMPONENT_EXPORT_ENTRYPOINT

src/mono/mono/metadata/class.c

@@ -4985,6 +4985,10 @@ mono_class_num_fields (MonoClass *klass)
 int
 mono_class_num_methods (MonoClass *klass)
 {
+	MonoImage *image = m_class_get_image (klass);
+	if (G_UNLIKELY (image->has_updates)) {
+		return mono_class_get_method_count (klass) + mono_metadata_update_get_num_methods_added (klass);
+	}
 	return mono_class_get_method_count (klass);
 }
 

src/mono/mono/metadata/icall-decl.h

@@ -185,6 +185,7 @@ ICALL_EXPORT void ves_icall_System_Runtime_Intrinsics_X86_X86Base___cpuidex (int
 
 ICALL_EXPORT void ves_icall_AssemblyExtensions_ApplyUpdate (MonoAssembly *assm, gconstpointer dmeta_bytes, int32_t dmeta_len, gconstpointer dil_bytes, int32_t dil_len, gconstpointer dpdb_bytes, int32_t dpdb_len);
 ICALL_EXPORT gint32 ves_icall_AssemblyExtensions_ApplyUpdateEnabled (gint32 just_component_check);
+ICALL_EXPORT gint32 ves_icall_AssemblyExtensions_ApplyUpdateEnabled (gint32 just_component_check);
 
 ICALL_EXPORT guint32 ves_icall_RuntimeTypeHandle_GetCorElementType (MonoQCallTypeHandle type_handle);
 

src/mono/mono/metadata/icall-def.h

@@ -331,6 +331,7 @@ HANDLES(FILEDI_2, "internal_from_handle_type", ves_icall_System_Reflection_Field
 ICALL_TYPE(MDUP, "System.Reflection.Metadata.MetadataUpdater", MDUP_1)
 NOHANDLES(ICALL(MDUP_1, "ApplyUpdateEnabled", ves_icall_AssemblyExtensions_ApplyUpdateEnabled))
 NOHANDLES(ICALL(MDUP_2, "ApplyUpdate_internal", ves_icall_AssemblyExtensions_ApplyUpdate))
+HANDLES(MDUP_3, "GetApplyUpdateCapabilities", ves_icall_AssemblyExtensions_GetApplyUpdateCapabilities, MonoString, 0, ())
 
 ICALL_TYPE(MBASE, "System.Reflection.MethodBase", MBASE_1)
 HANDLES(MBASE_1, "GetCurrentMethod", ves_icall_GetCurrentMethod, MonoReflectionMethod, 0, ())

src/mono/mono/metadata/icall.c

@@ -5334,6 +5334,15 @@ ves_icall_AssemblyExtensions_ApplyUpdate (MonoAssembly *assm,
 	mono_error_set_pending_exception (error);
 }
 
+MonoStringHandle
+ves_icall_AssemblyExtensions_GetApplyUpdateCapabilities (MonoError *error)
+{
+	MonoStringHandle s;
+	s = mono_string_new_handle (mono_enc_capabilities (), error);
+	return_val_if_nok (error, NULL_HANDLE_STRING);
+	return s;
+}
+
 gint32 ves_icall_AssemblyExtensions_ApplyUpdateEnabled (gint32 just_component_check)
 {
 	// if just_component_check is true, we only care whether the hot_reload component is enabled,

src/mono/mono/metadata/metadata-internals.h

@@ -816,6 +816,9 @@ enum MonoEnCDeltaOrigin {
 MONO_COMPONENT_API void
 mono_image_load_enc_delta (int delta_origin, MonoImage *base_image, gconstpointer dmeta, uint32_t dmeta_len, gconstpointer dil, uint32_t dil_len, gconstpointer dpdb, uint32_t dpdb_len, MonoError *error);
 
+MONO_COMPONENT_API const char*
+mono_enc_capabilities (void);
+
 gboolean
 mono_image_load_cli_header (MonoImage *image, MonoCLIImageInfo *iinfo);
 

src/mono/mono/metadata/metadata-update.c

@@ -76,6 +76,12 @@ mono_image_load_enc_delta (int origin, MonoImage *base_image, gconstpointer dmet
 	}
 }
 
+const char*
+mono_enc_capabilities (void)
+{
+	return mono_component_hot_reload ()->get_capabilities();
+}
+
 static void
 mono_image_close_except_pools_all_list (GList *images)
 {
@@ -217,4 +223,10 @@ uint32_t
 mono_metadata_update_get_num_fields_added (MonoClass *klass)
 {
 	return mono_component_hot_reload()->get_num_fields_added (klass);
+}
+
+uint32_t
+mono_metadata_update_get_num_methods_added (MonoClass *klass)
+{
+	return mono_component_hot_reload()->get_num_methods_added (klass);
 }

src/mono/mono/metadata/metadata-update.h

@@ -90,4 +90,7 @@ mono_metadata_update_added_fields_iter (MonoClass *klass, gboolean lazy, gpointe
 
 uint32_t
 mono_metadata_update_get_num_fields_added (MonoClass *klass);
+
+uint32_t
+mono_metadata_update_get_num_methods_added (MonoClass *klass);
 #endif /*__MONO_METADATA_UPDATE_H__*/