[debugger] Assert when async debug a generic method (mono#17727)

* When we try to call a method to get the async_id to do an async debug and we are trying to do this in a generic method like this: async Task<T> ExecuteAsync_Broken<T>() { await Task.Delay(2); return default; } We need to inflate the generic type before call the method or we will get the error: Could not execute the method because the containing type 'System.Runtime.CompilerServices.AsyncTaskMethodBuilder1[T_REF]’, is not fully instantiated. Fixes mono#17549 Fixes mono#17569 Cherry-picked by Alex Thibodeau -- some light massaging required
Unity-Technologies · Jun 15, 2020 · 51c8c04 · 51c8c04
1 parent e2b47cb
commit 51c8c04
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Showing 5 changed files with 60 additions and 9 deletions.
diff --git a/mcs/class/Mono.Debugger.Soft/Test/dtest-app.cs b/mcs/class/Mono.Debugger.Soft/Test/dtest-app.cs
@@ -366,6 +366,7 @@ public static void wait_one ()
 			new Tests ().invoke_abort ();
 		new Tests ().evaluate_method ();
 
+		test_async_debug_generics();
 		test_invalid_argument_assembly_get_type ();
 
 		return 3;
@@ -558,6 +559,17 @@ public static void ss7_3 ()
 		ss_nested_3 ();
 	}
 
+	[MethodImplAttribute (MethodImplOptions.NoInlining)]
+	public static void test_async_debug_generics () {
+		ExecuteAsync_Broken<object>().Wait ();
+	}
+
+	async static Task<T> ExecuteAsync_Broken<T>()
+	{
+		await Task.Delay(2);
+		return default;
+	}
+
 	[MethodImplAttribute (MethodImplOptions.NoInlining)]
 	public static void ss_nested_1 (int i) {
 	}

diff --git a/mcs/class/Mono.Debugger.Soft/Test/dtest.cs b/mcs/class/Mono.Debugger.Soft/Test/dtest.cs
@@ -4444,5 +4444,14 @@ public void Hash ()
 		}
 	}
 
+	[Test]
+	public void TestAsyncDebugGenerics () {
+		Event e = run_until ("test_async_debug_generics");
+		e = step_in_await ("test_async_debug_generics", e);
+		e = step_in_await ("MoveNext", e);
+		e = step_in_await ("MoveNext", e);
+		e = step_in_await ("MoveNext", e);
+		e = step_in_await ("MoveNext", e);
+	}
 } // class DebuggerTests
 } // namespace
diff --git a/mono/mini/debugger-agent.c b/mono/mini/debugger-agent.c
@@ -5448,6 +5448,30 @@ get_object_id_for_debugger_method (MonoClass* async_builder_class)
 	return method;
 }
 
+static MonoClass *
+get_class_to_get_builder_field(StackFrame *frame)
+{
+	MonoError error;
+	gpointer this_addr = get_this_addr (frame);
+	MonoClass *original_class = frame->method->klass;
+	MonoClass *ret;
+	if (!mono_class_is_valuetype(original_class) && mono_class_is_open_constructed_type (&original_class->byval_arg)) {
+		MonoObject *this_obj = *(MonoObject**)this_addr;
+		MonoGenericContext context;
+		MonoType *inflated_type;
+
+		g_assert (this_obj);
+		context = mono_get_generic_context_from_stack_frame (frame->ji, this_obj->vtable);
+		inflated_type = mono_class_inflate_generic_type_checked (&original_class->byval_arg, &context, &error);
+		mono_error_assert_ok (&error); /* FIXME don't swallow the error */
+
+		ret = mono_class_from_mono_type (inflated_type);
+		mono_metadata_free_type (inflated_type);
+		return ret;
+	}
+	return original_class;
+}
+
 /* Return the address of the AsyncMethodBuilder struct belonging to the state machine method pointed to by FRAME */
 static gpointer
 get_async_method_builder (StackFrame *frame)
@@ -5456,15 +5480,17 @@ get_async_method_builder (StackFrame *frame)
 	MonoClassField *builder_field;
 	gpointer builder;
 	guint8 *this_addr;
+	MonoClass* klass = frame->method->klass;
 
-	builder_field = mono_class_get_field_from_name (frame->method->klass, "<>t__builder");
+	klass = get_class_to_get_builder_field(frame);
+	builder_field = mono_class_get_field_from_name_full (klass, "<>t__builder", NULL);
 	g_assert (builder_field);
 
 	this_addr = get_this_addr (frame);
 	if (!this_addr)
 		return NULL;
 
-	if (mono_class_is_valuetype (frame->method->klass)) {
+	if (mono_class_is_valuetype (klass)) {
 		guint8 *vtaddr = *(guint8**)this_addr;
 		builder = (char*)vtaddr + mono_field_get_offset (builder_field) - sizeof (MonoObject);
 	} else {
@@ -5497,7 +5523,7 @@ get_this_async_id (StackFrame *frame)
 	if (!builder)
 		return 0;
 
-	builder_field = mono_class_get_field_from_name (frame->method->klass, "<>t__builder");
+	builder_field = mono_class_get_field_from_name (get_class_to_get_builder_field(frame), "<>t__builder");
 	g_assert (builder_field);
 
 	tls = (DebuggerTlsData *)mono_native_tls_get_value (debugger_tls_id);
@@ -5521,7 +5547,7 @@ get_this_async_id (StackFrame *frame)
 static gboolean
 set_set_notification_for_wait_completion_flag (StackFrame *frame)
 {
-	MonoClassField *builder_field = mono_class_get_field_from_name (frame->method->klass, "<>t__builder");
+	MonoClassField *builder_field = mono_class_get_field_from_name (get_class_to_get_builder_field(frame), "<>t__builder");
 	g_assert (builder_field);
 	gpointer builder = get_async_method_builder (frame);
 	g_assert (builder);

diff --git a/mono/mini/mini-exceptions.c b/mono/mini/mini-exceptions.c
@@ -805,8 +805,8 @@ get_generic_info_from_stack_frame (MonoJitInfo *ji, MonoContext *ctx)
 /*
  * generic_info is either a MonoMethodRuntimeGenericContext or a MonoVTable.
  */
-static MonoGenericContext
-get_generic_context_from_stack_frame (MonoJitInfo *ji, gpointer generic_info)
+MonoGenericContext
+mono_get_generic_context_from_stack_frame (MonoJitInfo *ji, gpointer generic_info)
 {
 	MonoGenericContext context = { NULL, NULL };
 	MonoClass *klass, *method_container_class;
@@ -851,6 +851,7 @@ get_generic_context_from_stack_frame (MonoJitInfo *ji, gpointer generic_info)
 	return context;
 }
 
+
 static MonoMethod*
 get_method_from_stack_frame (MonoJitInfo *ji, gpointer generic_info)
 {
@@ -860,7 +861,7 @@ get_method_from_stack_frame (MonoJitInfo *ji, gpointer generic_info)
 
 	if (!ji->has_generic_jit_info || !mono_jit_info_get_generic_jit_info (ji)->has_this)
 		return jinfo_get_method (ji);
-	context = get_generic_context_from_stack_frame (ji, generic_info);
+	context = mono_get_generic_context_from_stack_frame (ji, generic_info);
 
 	method = jinfo_get_method (ji);
 	method = mono_method_get_declaring_generic_method (method);
@@ -1386,7 +1387,7 @@ get_exception_catch_class (MonoJitExceptionInfo *ei, MonoJitInfo *ji, MonoContex
 
 	if (!ji->has_generic_jit_info || !mono_jit_info_get_generic_jit_info (ji)->has_this)
 		return catch_class;
-	context = get_generic_context_from_stack_frame (ji, get_generic_info_from_stack_frame (ji, ctx));
+	context = mono_get_generic_context_from_stack_frame (ji, get_generic_info_from_stack_frame (ji, ctx));
 
 	/* FIXME: we shouldn't inflate but instead put the
 	   type in the rgctx and fetch it from there.  It
@@ -3473,7 +3474,7 @@ mono_llvm_match_exception (MonoJitInfo *jinfo, guint32 region_start, guint32 reg
 			MonoType *inflated_type;
 
 			g_assert (rgctx || this_obj);
-			context = get_generic_context_from_stack_frame (jinfo, rgctx ? rgctx : this_obj->vtable);
+			context = mono_get_generic_context_from_stack_frame (jinfo, rgctx ? rgctx : this_obj->vtable);
 			inflated_type = mono_class_inflate_generic_type_checked (&catch_class->byval_arg, &context, &error);
 			mono_error_assert_ok (&error); /* FIXME don't swallow the error */
 

diff --git a/mono/mini/mini.h b/mono/mini/mini.h
@@ -2883,4 +2883,7 @@ gboolean MONO_SIG_HANDLER_SIGNATURE (mono_chain_signal);
 
 #endif
 
+MonoGenericContext
+mono_get_generic_context_from_stack_frame (MonoJitInfo *ji, gpointer generic_info);
+
 #endif /* __MONO_MINI_H__ */