[interp] Remove hack for nint/nfloat (#21382)

These structures are valuetypes, but their mint_type is a primitive. This means that a LDFLD applied on the type would have attempted to do a pointer dereference, because it saw that the current top of stack is not STACK_TYPE_VT. This was fixed in the past by passing the managed pointer to the valuetype rather than the valuetype itself, against the normal call convention, which lead to inconsistencies in the code.

This commit removes that hack and fixes the problem by ignoring LDFLD applied to nint/nfloat valuetypes in the first place.

1 files changed, 9 insertions, 36 deletions

diff --git a/mono/mini/interp/transform.c b/mono/mini/interp/transform.c
index 64e2d96d0d2..d07244ad441 100644
--- a/mono/mini/interp/transform.c
+++ b/mono/mini/interp/transform.c
@@ -1494,21 +1494,6 @@ interp_method_get_header (MonoMethod* method, MonoError *error)
 		return mono_method_get_header_internal (method, error);
 }
 
-/* stores top of stack as local and pushes address of it on stack */
-static void
-emit_store_value_as_local (TransformData *td, MonoType *src)
-{
-	int local = create_interp_local (td, mini_native_type_replace_type (src));
-
-	store_local (td, local);
-
-	interp_add_ins (td, MINT_LDLOCA_S);
-	push_simple_type (td, STACK_TYPE_MP);
-	interp_ins_set_dreg (td->last_ins, td->sp [-1].local);
-	interp_ins_set_sreg (td->last_ins, local);
-	td->locals [local].indirects++;
-}
-
 static gboolean
 interp_ip_in_cbb (TransformData *td, int il_offset)
 {
@@ -1800,15 +1785,15 @@ interp_handle_magic_type_intrinsics (TransformData *td, MonoMethod *target_metho
 		int src_size = mini_magic_type_size (NULL, src);
 		int dst_size = mini_magic_type_size (NULL, dst);
 
-		gboolean store_value_as_local = FALSE;
+		gboolean managed_fallback = FALSE;
 
 		switch (type_index) {
 		case 0: case 1:
 			if (!mini_magic_is_int_type (src) || !mini_magic_is_int_type (dst)) {
 				if (mini_magic_is_int_type (src))
-					store_value_as_local = TRUE;
+					managed_fallback = TRUE;
 				else if (mono_class_is_magic_float (src_klass))
-					store_value_as_local = TRUE;
+					managed_fallback = TRUE;
 				else
 					return FALSE;
 			}
@@ -1816,21 +1801,17 @@ interp_handle_magic_type_intrinsics (TransformData *td, MonoMethod *target_metho
 		case 2:
 			if (!mini_magic_is_float_type (src) || !mini_magic_is_float_type (dst)) {
 				if (mini_magic_is_float_type (src))
-					store_value_as_local = TRUE;
+					managed_fallback = TRUE;
 				else if (mono_class_is_magic_int (src_klass))
-					store_value_as_local = TRUE;
+					managed_fallback = TRUE;
 				else
 					return FALSE;
 			}
 			break;
 		}
 
-		if (store_value_as_local) {
-			emit_store_value_as_local (td, src);
-
-			/* emit call to managed conversion method */
+		if (managed_fallback)
 			return FALSE;
-		}
 
 		if (src_size > dst_size) { // 8 -> 4
 			switch (type_index) {
@@ -1887,15 +1868,6 @@ interp_handle_magic_type_intrinsics (TransformData *td, MonoMethod *target_metho
 		td->ip += 5;
 		return TRUE;
 	} else if (!strcmp ("CompareTo", tm) || !strcmp ("Equals", tm)) {
-		MonoType *arg = csignature->params [0];
-		int mt = mint_type (arg);
-
-		/* on 'System.n*::{CompareTo,Equals} (System.n*)' variant we need to push managed
-		 * pointer instead of value */
-		if (mt != MINT_TYPE_O)
-			emit_store_value_as_local (td, arg);
-
-		/* emit call to managed conversion method */
 		return FALSE;
 	} else if (!strcmp (".cctor", tm)) {
 		return FALSE;
@@ -2515,8 +2487,7 @@ interp_method_check_inlining (TransformData *td, MonoMethod *method, MonoMethodS
 	if (method->wrapper_type != MONO_WRAPPER_NONE)
 		return FALSE;
 
-	/* Our usage of `emit_store_value_as_local ()` for nint, nuint and nfloat
-	 * is kinda hacky, and doesn't work with the inliner */
+	// FIXME Re-enable this
 	if (mono_class_get_magic_index (method->klass) >= 0)
 		return FALSE;
 
@@ -5595,6 +5566,8 @@ generate_code (TransformData *td, MonoMethod *method, MonoMethodHeader *header,
 					td->sp--;
 					interp_emit_sfld_access (td, field, field_klass, mt, TRUE, error);
 					goto_if_nok (error, exit);
+				} else if (td->sp [-1].type != STACK_TYPE_O && td->sp [-1].type != STACK_TYPE_MP && (mono_class_is_magic_int (klass) || mono_class_is_magic_float (klass))) {
+					// No need to load anything, the value is already on the execution stack
 				} else if (td->sp [-1].type == STACK_TYPE_VT) {
 					/* First we pop the vt object from the stack. Then we push the field */
 					int opcode = MINT_LDFLD_VT_I1 + mt - MINT_TYPE_I1;