From 6dd9c9a58769af9e374b81b97b34c6953c8a19b1 Mon Sep 17 00:00:00 2001
From: Aleksey Kliger <alklig@microsoft.com>
Date: Mon, 1 Mar 2021 16:49:46 -0500
Subject: [PATCH] [sdb] Add MODULE_APPLY_CHANGES command for hot reload

---
 src/mono/mono/mini/debugger-agent.c    | 43 ++++++++++++++++++++++++++
 src/mono/mono/mini/debugger-protocol.h |  3 +-
 2 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/src/mono/mono/mini/debugger-agent.c b/src/mono/mono/mini/debugger-agent.c
index 8bece92c6d2941..311a2e80f61c77 100644
--- a/src/mono/mono/mini/debugger-agent.c
+++ b/src/mono/mono/mini/debugger-agent.c
@@ -6390,6 +6390,27 @@ get_types_for_source_file (gpointer key, gpointer value, gpointer user_data)
 	}
 }
 
+static gboolean
+module_apply_changes (MonoImage *image, MonoArray *dmeta, MonoArray *dil, MonoArray *dpdb, MonoError *error)
+{
+#ifdef ENABLE_METADATA_UPDATE
+	MonoDomain *domain = mono_domain_get ();
+	/* TODO: use dpdb */
+	gpointer dmeta_bytes = (gpointer)mono_array_addr_internal (dmeta, char, 0);
+	int32_t dmeta_len = mono_array_length_internal (dmeta);
+	gpointer dil_bytes = (gpointer)mono_array_addr_internal (dil, char, 0);
+	int32_t dil_len = mono_array_length_internal (dil);
+	gpointer dpdb_bytes = !dpdb ? NULL : (gpointer)mono_array_addr_internal (dpdb, char, 0);
+	int32_t dpdb_len = !dpdb ? 0 : mono_array_length_internal (dpdb);
+	mono_image_load_enc_delta (domain, image, dmeta_bytes, dmeta_len, dil_bytes, dil_len, error);
+	return is_ok (error);
+#else
+	mono_error_set_not_supported (error, "");
+	return FALSE;
+#endif
+}
+	
+
 static void
 buffer_add_cattr_arg (Buffer *buf, MonoType *t, MonoDomain *domain, MonoObject *val)
 {
@@ -7480,6 +7501,27 @@ module_commands (int command, guint8 *p, guint8 *end, Buffer *buf)
 		g_free (sourcelink);
 		break;			
 	}
+	case MDBGPROT_CMD_MODULE_APPLY_CHANGES: {
+		MonoImage *image = decode_moduleid (p, &p, end, &domain, &err);
+		if (err != ERR_NONE)
+			return err;
+		int dmeta_id = decode_objid (p, &p, end);
+		int dil_id = decode_objid (p, &p, end);
+		int dpdb_id = decode_objid (p, &p, end);
+		MonoObject *dmeta, *dil, *dpdb;
+		if ((err = get_object (dmeta_id, &dmeta)) != ERR_NONE)
+			return err;
+		if ((err = get_object (dil_id, &dil)) != ERR_NONE)
+			return err;
+		if ((err = get_object_allow_null (dpdb_id, &dpdb)) != ERR_NONE)
+			return err;
+		ERROR_DECL (error);
+		if (!module_apply_changes (image, (MonoArray *)dmeta, (MonoArray *)dil, (MonoArray *)dpdb, error)) {
+			mono_error_cleanup (error);
+			return ERR_LOADER_ERROR;
+		}
+		return ERR_NONE;
+	}
 	default:
 		return ERR_NOT_IMPLEMENTED;
 	}
@@ -9458,6 +9500,7 @@ static const char* assembly_cmds_str[] = {
 
 static const char* module_cmds_str[] = {
 	"GET_INFO",
+	"APPLY_CHANGES",
 };
 
 static const char* field_cmds_str[] = {
diff --git a/src/mono/mono/mini/debugger-protocol.h b/src/mono/mono/mini/debugger-protocol.h
index bdf8ee5b277d78..07dafdf1824c37 100644
--- a/src/mono/mono/mini/debugger-protocol.h
+++ b/src/mono/mono/mini/debugger-protocol.h
@@ -11,7 +11,7 @@
  */
 
 #define MAJOR_VERSION 2
-#define MINOR_VERSION 59
+#define MINOR_VERSION 60
 
 typedef enum {
 	MDBGPROT_CMD_COMPOSITE = 100
@@ -143,6 +143,7 @@ typedef enum {
 
 typedef enum {
 	MDBGPROT_CMD_MODULE_GET_INFO = 1,
+	MDBGPROT_CMD_MODULE_APPLY_CHANGES = 2,
 } MdbgProtCmdModule;
 
 typedef enum {