[release/9.0] [mono] Make the compressed interface bitmap feature usable (#120154)

* [mono][metadata] Enable compressed interface bitmap by default (#119694)

* [mono][metadata] Enable compressed interface bitmap by default

* Fix build on windows

* Fix publishing of compressed bitmap

Before this commit we were doing changes on the published data which is problematic for multithreaded environments. We ensure the bitmap is fully processed before publishing it so that we can rely on the data dependency memory ordering constraint for correctness.

* [mono] Enable configuration at runtime of the compressed interface bitmap feature (#119881)

* Add option to configure use of compressed interface bitmaps

This optimization is disabled by default. Enable it with `MONO_COMPRESSED_INTERFACE_BITMAP=1`

* Add support for detecting mismatch with aot images

Author: BrzVlad

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

@@ -1689,8 +1689,6 @@ mono_class_setup_count_virtual_methods (MonoClass *klass)
 	return vcount;
 }
 
-#ifdef COMPRESSED_INTERFACE_BITMAP
-
 /*
  * Compressed interface bitmap design.
  *
@@ -1745,7 +1743,7 @@ mono_compress_bitmap (uint8_t *dest, const uint8_t *bitmap, int size)
 	while (bitmap < end) {
 		if (*bitmap || numz == 255) {
 			if (dest) {
-				*dest++ = numz;
+				*dest++ = (uint8_t)numz;
 				*dest++ = *bitmap;
 			}
 			res += 2;
@@ -1759,7 +1757,7 @@ mono_compress_bitmap (uint8_t *dest, const uint8_t *bitmap, int size)
 	if (numz) {
 		res += 2;
 		if (dest) {
-			*dest++ = numz;
+			*dest++ = (uint8_t)numz;
 			*dest++ = 0;
 		}
 	}
@@ -1780,7 +1778,7 @@ mono_compress_bitmap (uint8_t *dest, const uint8_t *bitmap, int size)
  * FALSE otherwise.
  */
 int
-mono_class_interface_match (const uint8_t *bitmap, int id)
+mono_class_interface_match_compressed (const uint8_t *bitmap, int id)
 {
 	while (TRUE) {
 		id -= bitmap [0] * 8;
@@ -1793,7 +1791,6 @@ mono_class_interface_match (const uint8_t *bitmap, int id)
 		id -= 8;
 	}
 }
-#endif
 
 static char*
 concat_two_strings_with_zero (MonoImage *image, const char *s1, const char *s2)

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

@@ -17,6 +17,7 @@
 #include "mono/utils/mono-error-internals.h"
 #include "mono/utils/mono-memory-model.h"
 #include "mono/utils/mono-compiler.h"
+#include "mono/utils/options.h"
 
 #define MONO_CLASS_IS_ARRAY(c) (m_class_get_rank (c))
 
@@ -287,12 +288,6 @@ union _MonoClassSizes {
 		int generic_param_token; /* for generic param types, both var and mvar */
 };
 
-/* enabled only with small config for now: we might want to do it unconditionally */
-#ifdef MONO_SMALL_CONFIG
-#define COMPRESSED_INTERFACE_BITMAP 1
-#endif
-
-
 #ifdef ENABLE_CHECKED_BUILD_PRIVATE_TYPES
 #define MONO_CLASS_DEF_PRIVATE 1
 #endif
@@ -321,14 +316,12 @@ union _MonoClassSizes {
 #undef MONO_CLASS_GETTER
 #undef MONO_CLASS_OFFSET
 
-#ifdef COMPRESSED_INTERFACE_BITMAP
 int mono_compress_bitmap (uint8_t *dest, const uint8_t *bitmap, int size);
-int mono_class_interface_match (const uint8_t *bitmap, int id);
-#else
+int mono_class_interface_match_compressed (const uint8_t *bitmap, int id);
+
 #define mono_class_interface_match(bmap,uiid) ((bmap) [(uiid) >> 3] & (1 << ((uiid)&7)))
-#endif
 
-#define MONO_CLASS_IMPLEMENTS_INTERFACE(k,uiid) (((uiid) <= m_class_get_max_interface_id (k)) && mono_class_interface_match (m_class_get_interface_bitmap (k), (uiid)))
+#define MONO_CLASS_IMPLEMENTS_INTERFACE(k,uiid) (((uiid) <= m_class_get_max_interface_id (k)) && (mono_opt_compressed_interface_bitmap ? mono_class_interface_match_compressed (m_class_get_interface_bitmap (k), (uiid)) : mono_class_interface_match (m_class_get_interface_bitmap (k), (uiid))))
 
 #define MONO_VTABLE_AVAILABLE_GC_BITS 4
 
@@ -378,7 +371,7 @@ struct MonoVTable {
 
 #define MONO_SIZEOF_VTABLE (sizeof (MonoVTable) - MONO_ZERO_LEN_ARRAY * SIZEOF_VOID_P)
 
-#define MONO_VTABLE_IMPLEMENTS_INTERFACE(vt,uiid) (((uiid) <= (vt)->max_interface_id) && mono_class_interface_match ((vt)->interface_bitmap, (uiid)))
+#define MONO_VTABLE_IMPLEMENTS_INTERFACE(vt,uiid) (((uiid) <= (vt)->max_interface_id) && (mono_opt_compressed_interface_bitmap ? mono_class_interface_match_compressed ((vt)->interface_bitmap, (uiid)) : mono_class_interface_match ((vt)->interface_bitmap, (uiid))))
 
 /*
  * Generic instantiation data type encoding.

src/mono/mono/metadata/class-setup-vtable.c

@@ -56,20 +56,18 @@ print_implemented_interfaces (MonoClass *klass)
 			printf ("(%d,F)", i);
 	printf ("\n");
 	printf ("Dump interface flags:");
-#ifdef COMPRESSED_INTERFACE_BITMAP
-	{
+	if (mono_opt_compressed_interface_bitmap) {
 		const uint8_t* p = klass->interface_bitmap;
 		guint32 i = klass->max_interface_id;
 		while (i > 0) {
 			printf (" %d x 00 %02X", p [0], p [1]);
 			i -= p [0] * 8;
 			i -= 8;
 		}
+	} else {
+		for (guint32 i = 0; i < ((((klass->max_interface_id + 1) >> 3)) + (((klass->max_interface_id + 1) & 7) ? 1 : 0)); i++)
+			printf (" %02X", klass->interface_bitmap [i]);
 	}
-#else
-	for (guint32 i = 0; i < ((((klass->max_interface_id + 1) >> 3)) + (((klass->max_interface_id + 1) & 7)? 1 :0)); i++)
-		printf (" %02X", klass->interface_bitmap [i]);
-#endif
 	printf ("\n");
 	while (klass != NULL) {
 		printf ("[LEVEL %d] Implemented interfaces by class %s:\n", ancestor_level, klass->name);
@@ -329,11 +327,12 @@ mono_class_setup_interface_offsets_internal (MonoClass *klass, int cur_slot, int
 			klass->interface_offsets_packed = (guint16 *)mono_class_alloc (klass, sizeof (guint16) * interface_offsets_count);
 		}
 		bsize = (sizeof (guint8) * ((max_iid + 1) >> 3)) + (((max_iid + 1) & 7)? 1 :0);
-#ifdef COMPRESSED_INTERFACE_BITMAP
-		bitmap = g_malloc0 (bsize);
-#else
-		bitmap = (uint8_t *)mono_class_alloc0 (klass, bsize);
-#endif
+
+		if (mono_opt_compressed_interface_bitmap)
+			bitmap = g_malloc0 (bsize);
+		else
+			bitmap = (uint8_t *)mono_class_alloc0 (klass, bsize);
+
 		for (int i = 0; i < interface_offsets_count; i++) {
 			guint32 id = interfaces_full [i]->interface_id;
 			bitmap [id >> 3] |= (1 << (id & 7));
@@ -343,14 +342,16 @@ mono_class_setup_interface_offsets_internal (MonoClass *klass, int cur_slot, int
 			}
 		}
 		if (!klass->interface_bitmap) {
-#ifdef COMPRESSED_INTERFACE_BITMAP
-			int i = mono_compress_bitmap (NULL, bitmap, bsize);
-			klass->interface_bitmap = mono_class_alloc0 (klass, i);
-			mono_compress_bitmap (klass->interface_bitmap, bitmap, bsize);
-			g_free (bitmap);
-#else
-			klass->interface_bitmap = bitmap;
-#endif
+			if (mono_opt_compressed_interface_bitmap) {
+				int len = mono_compress_bitmap (NULL, bitmap, bsize);
+				uint8_t *compressed_bitmap = mono_class_alloc0 (klass, len);
+				mono_compress_bitmap (compressed_bitmap, bitmap, bsize);
+				g_free (bitmap);
+
+				klass->interface_bitmap = compressed_bitmap;
+			} else {
+				klass->interface_bitmap = bitmap;
+			}
 		}
 	}
 end:

src/mono/mono/metadata/jit-icall-reg.h

@@ -162,7 +162,7 @@ MONO_JIT_ICALL (mono_break) \
 MONO_JIT_ICALL (mono_byvalarray_to_byte_array) \
 MONO_JIT_ICALL (mono_chkstk_win64) \
 MONO_JIT_ICALL (mono_ckfinite) \
-MONO_JIT_ICALL (mono_class_interface_match) \
+MONO_JIT_ICALL (mono_class_interface_match_compressed) \
 MONO_JIT_ICALL (mono_class_static_field_address) \
 MONO_JIT_ICALL (mono_compile_method_icall) \
 MONO_JIT_ICALL (mono_context_get_icall) \

src/mono/mono/metadata/marshal.c

@@ -4860,11 +4860,8 @@ get_virtual_stelemref_kind (MonoClass *element_class)
 
 	/* Compressed interface bitmaps require code that is quite complex, so don't optimize for it. */
 	if (MONO_CLASS_IS_INTERFACE_INTERNAL (element_class) && !mono_class_has_variant_generic_params (element_class))
-#ifdef COMPRESSED_INTERFACE_BITMAP
-		return STELEMREF_COMPLEX;
-#else
-		return STELEMREF_INTERFACE;
-#endif
+		return mono_opt_compressed_interface_bitmap ? STELEMREF_COMPLEX : STELEMREF_INTERFACE;
+
 	/*Arrays are sealed but are covariant on their element type, We can't use any of the fast paths.*/
 	if (m_class_get_rank (element_class) || mono_class_has_variant_generic_params (element_class))
 		return STELEMREF_COMPLEX;

src/mono/mono/metadata/metadata.c

@@ -1975,6 +1975,15 @@ mono_metadata_init (void)
 		g_hash_table_insert (type_cache, (gpointer) &builtin_types [i], (gpointer) &builtin_types [i]);
 
 	mono_metadata_update_init ();
+
+	char *compressed_bmap = g_getenv ("MONO_COMPRESSED_INTERFACE_BITMAP");
+	if (compressed_bmap) {
+		if (compressed_bmap [0] == '1')
+			mono_opt_compressed_interface_bitmap = TRUE;
+		else if (compressed_bmap [0] == '0')
+			mono_opt_compressed_interface_bitmap = FALSE;
+		g_free (compressed_bmap);
+	}
 }
 
 /*

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

@@ -15120,6 +15120,9 @@ aot_assembly (MonoAssembly *ass, guint32 jit_opts, MonoAotOptions *aot_options)
 		acfg->is_full_aot = TRUE;
 	}
 
+	if (mono_opt_compressed_interface_bitmap)
+		acfg->flags = (MonoAotFileFlags)(acfg->flags | MONO_AOT_FILE_FLAG_COMPRESSED_INTERFACE_BITMAP);
+
 	if (mini_safepoints_enabled ())
 		acfg->flags = (MonoAotFileFlags)(acfg->flags | MONO_AOT_FILE_FLAG_SAFEPOINTS);
 

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

@@ -1631,7 +1631,7 @@ check_usable (MonoAssembly *assembly, MonoAotFileInfo *info, guint8 *blob, char
 	char *build_info;
 	char *msg = NULL;
 	gboolean usable = TRUE;
-	gboolean full_aot, interp, safepoints;
+	gboolean full_aot, interp, safepoints, compressed_interface_bmap;
 	guint32 excluded_cpu_optimizations;
 
 	if (strcmp (assembly->image->guid, (const char*)info->assembly_guid)) {
@@ -1713,6 +1713,13 @@ check_usable (MonoAssembly *assembly, MonoAotFileInfo *info, guint8 *blob, char
 	}
 #endif
 
+	compressed_interface_bmap = info->flags & MONO_AOT_FILE_FLAG_COMPRESSED_INTERFACE_BITMAP;
+	if ((mono_opt_compressed_interface_bitmap && !compressed_interface_bmap) ||
+			(!mono_opt_compressed_interface_bitmap && compressed_interface_bmap)) {
+		msg = g_strdup ("mismatch with compressed interface bitmap feature");
+		usable = FALSE;
+	}
+
 	*out_msg = msg;
 	return usable;
 }

src/mono/mono/mini/aot-runtime.h

@@ -11,7 +11,7 @@
 #include "mini.h"
 
 /* Version number of the AOT file format */
-#define MONO_AOT_FILE_VERSION 186
+#define MONO_AOT_FILE_VERSION 187
 
 #define MONO_AOT_TRAMP_PAGE_SIZE 16384
 
@@ -74,7 +74,8 @@ typedef enum {
 	MONO_AOT_FILE_FLAG_SEPARATE_DATA = 64,
 	MONO_AOT_FILE_FLAG_EAGER_LOAD = 128,
 	MONO_AOT_FILE_FLAG_INTERP = 256,
-	MONO_AOT_FILE_FLAG_CODE_EXEC_ONLY = 512
+	MONO_AOT_FILE_FLAG_CODE_EXEC_ONLY = 512,
+	MONO_AOT_FILE_FLAG_COMPRESSED_INTERFACE_BITMAP = 1024
 } MonoAotFileFlags;
 
 typedef enum {

src/mono/mono/mini/mini-runtime.c

@@ -5091,9 +5091,9 @@ register_icalls (void)
 #endif
 	register_icall (mono_ckfinite, mono_icall_sig_double_double, FALSE);
 
-#ifdef COMPRESSED_INTERFACE_BITMAP
-	register_icall (mono_class_interface_match, mono_icall_sig_uint32_ptr_int32, TRUE);
-#endif
+	// opt is initialized because mono_metadata_init is ran before this
+	if (mono_opt_compressed_interface_bitmap)
+		register_icall (mono_class_interface_match_compressed, mono_icall_sig_uint32_ptr_int32, TRUE);
 
 	/* other jit icalls */
 	register_icall (ves_icall_mono_delegate_ctor, mono_icall_sig_void_object_object_ptr, FALSE);