[mono][interp] Fix execution of delegate invoke wrapper with interpreter

src/mono/mono/cil/opcode.def

@@ -328,6 +328,8 @@ OPDEF(CEE_MONO_GET_SP, "mono_get_sp", Pop0, PushI, InlineNone, 0, 2, 0xF0, 0x20,
 OPDEF(CEE_MONO_METHODCONST, "mono_methodconst", Pop0, PushI, InlineI, 0, 2, 0xF0, 0x21, NEXT)
 OPDEF(CEE_MONO_PINVOKE_ADDR_CACHE, "mono_pinvoke_addr_cache", Pop0, PushI, InlineI, 0, 2, 0xF0, 0x22, NEXT)
 OPDEF(CEE_MONO_REMAP_OVF_EXC, "mono_remap_ovf_exc", Pop0, Push0, InlineI, 0, 2, 0xF0, 0x23, NEXT)
+OPDEF(CEE_MONO_LDVIRTFTN_DELEGATE, "mono_ldvirtftn_delegate", PopI+PopI, PushI, InlineNone, 0, 2, 0xF0, 0x24, NEXT)
+
 #ifndef OPALIAS
 #define _MONO_CIL_OPALIAS_DEFINED_
 #define OPALIAS(a,s,r)

src/mono/mono/metadata/marshal-lightweight.c

@@ -2052,7 +2052,8 @@ emit_delegate_invoke_internal_ilgen (MonoMethodBuilder *mb, MonoMethodSignature
 			}
 			mono_mb_emit_ldarg_addr (mb, 1);
 			mono_mb_emit_ldarg (mb, 0);
-			mono_mb_emit_icall (mb, mono_get_addr_compiled_method);
+			mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
+			mono_mb_emit_byte (mb, CEE_MONO_LDVIRTFTN_DELEGATE);
 			mono_mb_emit_op (mb, CEE_CALLI, target_method_sig);
 		} else {
 			mono_mb_emit_byte (mb, CEE_LDNULL);

src/mono/mono/mini/interp/interp.c

@@ -3863,6 +3863,34 @@ max_d (double lhs, double rhs)
 		return fmax (lhs, rhs);
 }
 
+// Equivalent of mono_get_addr_compiled_method
+static gpointer
+interp_ldvirtftn_delegate (gpointer arg, MonoDelegate *del)
+{
+	MonoMethod *virtual_method = del->method;
+	ERROR_DECL(error);
+
+	MonoClass *klass = del->object.vtable->klass;
+	MonoMethod *invoke = mono_get_delegate_invoke_internal (klass);
+	MonoMethodSignature *invoke_sig = mono_method_signature_internal (invoke);
+
+	MonoClass *arg_class = NULL;
+	if (m_type_is_byref (invoke_sig->params [0])) {
+		arg_class = mono_class_from_mono_type_internal (invoke_sig->params [0]);
+	} else {
+		MonoObject *object = (MonoObject*)arg;
+		arg_class = object->vtable->klass;
+	}
+
+	MonoMethod *res = mono_class_get_virtual_method (arg_class, virtual_method, error);
+	mono_error_assert_ok (error);
+
+	gboolean need_unbox = m_class_is_valuetype (res->klass) && !m_class_is_valuetype (virtual_method->klass);
+
+	InterpMethod *imethod = mono_interp_get_imethod (res);
+	return imethod_to_ftnptr (imethod, need_unbox);
+}
+
 /*
  * If CLAUSE_ARGS is non-null, start executing from it.
  * The ERROR argument is used to avoid declaring an error object for every interp frame, its not used
@@ -7794,6 +7822,15 @@ MINT_IN_CASE(MINT_BRTRUE_I8_SP) ZEROP_SP(gint64, !=); MINT_IN_BREAK;
 			ip += 3;
 			MINT_IN_BREAK;
 		}
+		MINT_IN_CASE(MINT_LDVIRTFTN_DELEGATE) {
+			gpointer arg = LOCAL_VAR (ip [2], gpointer);
+			MonoDelegate *del = LOCAL_VAR (ip [3], MonoDelegate*);
+			NULL_CHECK (arg);
+
+			LOCAL_VAR (ip [1], gpointer) = interp_ldvirtftn_delegate (arg, del);
+			ip += 4;
+			MINT_IN_BREAK;
+		}
 
 #define MATH_UNOP(mathfunc) \
 	LOCAL_VAR (ip [1], double) = mathfunc (LOCAL_VAR (ip [2], double)); \

src/mono/mono/mini/interp/mintops.def

@@ -732,6 +732,7 @@ OPDEF(MINT_SDB_INTR_LOC, "sdb_intr_loc", 1, 0, 0, MintOpNoArgs)
 OPDEF(MINT_SDB_SEQ_POINT, "sdb_seq_point", 1, 0, 0, MintOpNoArgs)
 OPDEF(MINT_SDB_BREAKPOINT, "sdb_breakpoint", 1, 0, 0, MintOpNoArgs)
 OPDEF(MINT_LD_DELEGATE_METHOD_PTR, "ld_delegate_method_ptr", 3, 1, 1, MintOpNoArgs)
+OPDEF(MINT_LDVIRTFTN_DELEGATE, "ldvirtftn_delegate", 4, 1, 2, MintOpNoArgs)
 
 // Math intrinsics
 // double

src/mono/mono/mini/interp/transform.c

@@ -8056,6 +8056,16 @@ generate_code (TransformData *td, MonoMethod *method, MonoMethodHeader *header,
 					push_simple_type (td, STACK_TYPE_I);
 					interp_ins_set_dreg (td->last_ins, td->sp [-1].var);
 					break;
+				case CEE_MONO_LDVIRTFTN_DELEGATE:
+					CHECK_STACK (td, 2);
+					td->sp -= 2;
+					td->ip += 1;
+					interp_add_ins (td, MINT_LDVIRTFTN_DELEGATE);
+					interp_ins_set_sregs2 (td->last_ins, td->sp [0].var, td->sp [1].var);
+					push_simple_type (td, STACK_TYPE_I);
+					interp_ins_set_dreg (td->last_ins, td->sp [-1].var);
+					break;
+
 				case CEE_MONO_CALLI_EXTRA_ARG: {
 					int saved_local = td->sp [-1].var;
 					/* Same as CEE_CALLI, except that we drop the extra arg required for llvm specific behaviour */

src/mono/mono/mini/method-to-ir.c

@@ -11594,6 +11594,14 @@ mono_method_to_ir (MonoCompile *cfg, MonoMethod *method, MonoBasicBlock *start_b
 			*sp++ = ins;
 			break;
 		}
+		case MONO_CEE_MONO_LDVIRTFTN_DELEGATE: {
+			CHECK_STACK (2);
+			sp -= 2;
+
+			ins = mono_emit_jit_icall (cfg, mono_get_addr_compiled_method, sp);
+			*sp++ = ins;
+			break;
+		}
 		case MONO_CEE_MONO_CALLI_EXTRA_ARG: {
 			MonoInst *addr;
 			MonoInst *arg;