Throw MemberAccessException when abstract class is used with newobj instruction

Author: joncham

mono/metadata/class-internals.h

@@ -225,6 +225,7 @@ typedef enum {
 	MONO_EXCEPTION_OUT_OF_MEMORY = 14,
 	MONO_EXCEPTION_INLINE_FAILED = 15,
 	MONO_EXCEPTION_MONO_ERROR = 16,
+	MONO_EXCEPTION_MEMBER_ACCESS = 17,
 	/* add other exception type */
 } MonoExceptionType;
 

mono/mini/method-to-ir.c

@@ -3653,6 +3653,14 @@ handle_alloc (MonoCompile *cfg, MonoClass *klass, gboolean for_box, int context_
 	MonoInst *iargs [2];
 	void *alloc_ftn;
 
+	if (mono_class_get_flags (klass) & TYPE_ATTRIBUTE_ABSTRACT)	{
+		char* full_name = mono_type_get_full_name (klass);
+		cfg->exception_message = g_strdup_printf ("Cannot create an abstract class: %s", full_name);
+		g_free (full_name);
+		mono_cfg_set_exception (cfg, MONO_EXCEPTION_MEMBER_ACCESS);
+		return NULL;
+	}
+
 	if (context_used) {
 		MonoInst *data;
 		MonoRgctxInfoType rgctx_info;

mono/mini/mini.c

@@ -4187,6 +4187,7 @@ mono_jit_compile_method_inner (MonoMethod *method, MonoDomain *target_domain, in
 	case MONO_EXCEPTION_TYPE_LOAD:
 	case MONO_EXCEPTION_MISSING_FIELD:
 	case MONO_EXCEPTION_MISSING_METHOD:
+	case MONO_EXCEPTION_MEMBER_ACCESS:
 	case MONO_EXCEPTION_FILE_NOT_FOUND:
 	case MONO_EXCEPTION_BAD_IMAGE:
 	case MONO_EXCEPTION_INVALID_PROGRAM: {
@@ -4206,6 +4207,8 @@ mono_jit_compile_method_inner (MonoMethod *method, MonoDomain *target_domain, in
 				ex = mono_get_exception_bad_image_format (cfg->exception_message);
 			else if (cfg->exception_type == MONO_EXCEPTION_INVALID_PROGRAM)
 				ex = mono_exception_from_name_msg (mono_defaults.corlib, "System", "InvalidProgramException", cfg->exception_message);
+			else if (cfg->exception_type == MONO_EXCEPTION_MEMBER_ACCESS)
+				ex = mono_exception_from_name_msg (mono_defaults.corlib, "System", "MemberAccessException", cfg->exception_message);
 			else
 				g_assert_not_reached ();
 		}

mono/tests/Makefile.am

@@ -608,7 +608,8 @@ TESTS_IL_SRC=			\
 	gsharing-valuetype-layout.il	\
 	invalid_generic_instantiation.il \
 	bug-45841-fpstack-exceptions.il \
-	instance_tailrec.il
+	instance_tailrec.il \
+	newobj-abstract.il
 
 TESTS_GSHARED_SRC = \
 	generics-sharing.2.cs	\

mono/tests/newobj-abstract.il

@@ -0,0 +1,61 @@
+.assembly extern mscorlib {}
+
+.assembly 'newobj-abstract' {}
+
+.class private auto ansi beforefieldinit Program
+       extends [mscorlib]System.Object
+{
+  .method public hidebysig static int32  Main() cil managed
+  {
+    .entrypoint
+    .locals init (int32 V_0)
+
+    ldc.i4.1
+    stloc.0
+    .try
+    {
+      call       void Program::NewAbstract()
+      leave.s    leavetarget
+
+    }  // end .try
+    catch [mscorlib]System.MemberAccessException 
+    {
+      pop
+      ldc.i4.0
+      stloc.0
+      leave.s    leavetarget
+    }
+leavetarget:
+    ldloc.0
+    ret
+  } // end of method Program::Main
+
+  .method public hidebysig static void  NewAbstract() cil managed
+  {
+    newobj     instance void Foo::.ctor()
+    call       void [mscorlib]System.GC::KeepAlive(object)
+    ret
+  }
+
+  .method public hidebysig specialname rtspecialname 
+          instance void  .ctor() cil managed
+  {
+    ldarg.0
+    call instance void [mscorlib]System.Object::.ctor()
+    ret
+  }
+
+}
+
+.class private abstract auto ansi beforefieldinit Foo
+       extends [mscorlib]System.Object
+{
+  .method public hidebysig specialname rtspecialname 
+          instance void  .ctor() cil managed
+  {
+    ldarg.0
+    call instance void [mscorlib]System.Object::.ctor()
+    ret
+  }
+
+}