From 51d797e59b6406b06e8e471907ef4941d0f3bb0c Mon Sep 17 00:00:00 2001
From: Zoltan Varga <vargaz@gmail.com>
Date: Wed, 8 Mar 2023 09:12:23 -0500
Subject: [PATCH] [mono][arm64] Implement delegate virtual invoke trampolines.
 (#83028)

---
 src/mono/mono/mini/mini-arm64.c | 67 +++++++++++++++++++++++++++++++++++++++--
 1 file changed, 64 insertions(+), 3 deletions(-)

diff --git a/src/mono/mono/mini/mini-arm64.c b/src/mono/mono/mini/mini-arm64.c
index 843e18a..d1f1f93 100644
--- a/src/mono/mono/mini/mini-arm64.c
+++ b/src/mono/mono/mini/mini-arm64.c
@@ -160,6 +160,49 @@ get_delegate_invoke_impl (gboolean has_target, gboolean param_count, guint32 *co
 	return MINI_ADDR_TO_FTNPTR (start);
 }
 
+#define MAX_VIRTUAL_DELEGATE_OFFSET 32
+
+static gpointer
+get_delegate_virtual_invoke_impl (MonoTrampInfo **info, gboolean load_imt_reg, int offset)
+{
+	guint8 *code, *start;
+	const int size = 20;
+	char *tramp_name;
+	GSList *unwind_ops;
+
+	if (offset / (int)sizeof (target_mgreg_t) > MAX_VIRTUAL_DELEGATE_OFFSET)
+		return NULL;
+
+	MINI_BEGIN_CODEGEN ();
+
+	start = code = mono_global_codeman_reserve (size);
+
+	unwind_ops = mono_arch_get_cie_program ();
+
+	/* Replace the this argument with the target */
+	arm_ldrx (code, ARMREG_R0, ARMREG_R0, MONO_STRUCT_OFFSET (MonoDelegate, target));
+
+	if (load_imt_reg)
+		// FIXME:
+		g_assert_not_reached ();
+
+	/* Load this->vtable [offset] */
+	arm_ldrx (code, ARMREG_IP0, ARMREG_R0, MONO_STRUCT_OFFSET (MonoObject, vtable));
+	arm_ldrx (code, ARMREG_IP0, ARMREG_IP0, offset);
+
+	code = mono_arm_emit_brx (code, ARMREG_IP0);
+
+	g_assert ((code - start) <= size);
+
+	MINI_END_CODEGEN (start, code - start, MONO_PROFILER_CODE_BUFFER_DELEGATE_INVOKE, NULL);
+
+	tramp_name = mono_get_delegate_virtual_invoke_impl_name (load_imt_reg, offset);
+	*info = mono_tramp_info_create (tramp_name, start, GPTRDIFF_TO_UINT32 (code - start), NULL, unwind_ops);
+	g_free (tramp_name);
+
+	return start;
+}
+
 /*
  * mono_arch_get_delegate_invoke_impls:
  *
@@ -172,19 +215,26 @@ mono_arch_get_delegate_invoke_impls (void)
 	GSList *res = NULL;
 	guint8 *code;
 	guint32 code_len;
-	int i;
 	char *tramp_name;
+	MonoTrampInfo *info = NULL;
 
 	code = (guint8*)get_delegate_invoke_impl (TRUE, 0, &code_len);
 	res = g_slist_prepend (res, mono_tramp_info_create ("delegate_invoke_impl_has_target", code, code_len, NULL, NULL));
 
-	for (i = 0; i <= MAX_ARCH_DELEGATE_PARAMS; ++i) {
+	for (int i = 0; i <= MAX_ARCH_DELEGATE_PARAMS; ++i) {
 		code = (guint8*)get_delegate_invoke_impl (FALSE, i, &code_len);
 		tramp_name = g_strdup_printf ("delegate_invoke_impl_target_%d", i);
 		res = g_slist_prepend (res, mono_tramp_info_create (tramp_name, code, code_len, NULL, NULL));
 		g_free (tramp_name);
 	}
 
+	for (int i = 0; i <= MAX_VIRTUAL_DELEGATE_OFFSET; ++i) {
+		get_delegate_virtual_invoke_impl (&info, FALSE, i * TARGET_SIZEOF_VOID_P);
+		res = g_slist_prepend (res, info);
+		//get_delegate_virtual_invoke_impl (&info, TRUE, i * TARGET_SIZEOF_VOID_P);
+		//res = g_slist_prepend (res, info);
+	}
+
 	return res;
 }
 
@@ -243,7 +293,18 @@ mono_arch_get_delegate_invoke_impl (MonoMethodSignature *sig, gboolean has_targe
 gpointer
 mono_arch_get_delegate_virtual_invoke_impl (MonoMethodSignature *sig, MonoMethod *method, int offset, gboolean load_imt_reg)
 {
-	return NULL;
+	MonoTrampInfo *info;
+	gpointer code;
+
+	if (load_imt_reg)
+		// FIXME:
+		return FALSE;
+
+	code = get_delegate_virtual_invoke_impl (&info, load_imt_reg, offset);
+	if (code)
+		mono_tramp_info_register (info, NULL);
+
+	return code;
 }
 
 gpointer
-- 
2.7.4