Fixed ObjC typechecking, particularly case with protocols

From-SVN: r57250

gcc/ChangeLog

+Tue Sep 17 13:58:04 2002  Nicola Pero  <n.pero@mi.flashnet.it>
+
+	Fix PR/7014 and related objc bugs:
+	* c-typeck.c (comp_target_types): Added a reflexive argument.
+	Pass it to ObjC when/if calling objc_comptypes().  Updated all
+	callers to provide the appropriate reflexive argument.
+	* objc/objc-act.c (objc_comptypes): Carefully checked and fixed
+	typechecking for all cases of comparisons and assignments,
+	particularly the obscure and less common ones involving protocols.
+
 2002-09-17  Nick Clifton  <nickc@redhat.com>
 
 	* machmode.def (V1DImode): New mode.  A single element vector.

gcc/c-typeck.c

@@ -51,7 +51,7 @@ static int missing_braces_mentioned;
 static int undeclared_variable_notice;
 
 static tree qualify_type		PARAMS ((tree, tree));
-static int comp_target_types		PARAMS ((tree, tree));
+static int comp_target_types		PARAMS ((tree, tree, int));
 static int function_types_compatible_p	PARAMS ((tree, tree));
 static int type_lists_compatible_p	PARAMS ((tree, tree));
 static tree decl_constant_value_for_broken_optimization PARAMS ((tree));
@@ -579,16 +579,21 @@ comptypes (type1, type2)
 }
 
 /* Return 1 if TTL and TTR are pointers to types that are equivalent,
-   ignoring their qualifiers.  */
+   ignoring their qualifiers.  REFLEXIVE is only used by ObjC - set it
+   to 1 or 0 depending if the check of the pointer types is meant to
+   be reflexive or not (typically, assignments are not reflexive,
+   while comparisons are reflexive).
+*/
 
 static int
-comp_target_types (ttl, ttr)
+comp_target_types (ttl, ttr, reflexive)
      tree ttl, ttr;
+     int reflexive;
 {
   int val;
 
   /* Give objc_comptypes a crack at letting these types through.  */
-  if ((val = objc_comptypes (ttl, ttr, 1)) >= 0)
+  if ((val = objc_comptypes (ttl, ttr, reflexive)) >= 0)
     return val;
 
   val = comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (ttl)),
@@ -1958,7 +1963,7 @@ build_binary_op (code, orig_op0, orig_op1, convert_p)
       /* Subtraction of two similar pointers.
 	 We must subtract them as integers, then divide by object size.  */
       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
-	  && comp_target_types (type0, type1))
+	  && comp_target_types (type0, type1, 1))
 	return pointer_diff (op0, op1);
       /* Handle pointer minus int.  Just like pointer plus int.  */
       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
@@ -2148,7 +2153,7 @@ build_binary_op (code, orig_op0, orig_op1, convert_p)
 	  /* Anything compares with void *.  void * compares with anything.
 	     Otherwise, the targets must be compatible
 	     and both must be object or both incomplete.  */
-	  if (comp_target_types (type0, type1))
+	  if (comp_target_types (type0, type1, 1))
 	    result_type = common_type (type0, type1);
 	  else if (VOID_TYPE_P (tt0))
 	    {
@@ -2195,7 +2200,7 @@ build_binary_op (code, orig_op0, orig_op1, convert_p)
 	shorten = 1;
       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
 	{
-	  if (comp_target_types (type0, type1))
+	  if (comp_target_types (type0, type1, 1))
 	    {
 	      result_type = common_type (type0, type1);
 	      if (pedantic 
@@ -2220,7 +2225,7 @@ build_binary_op (code, orig_op0, orig_op1, convert_p)
 	short_compare = 1;
       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
 	{
-	  if (comp_target_types (type0, type1))
+	  if (comp_target_types (type0, type1, 1))
 	    {
 	      result_type = common_type (type0, type1);
 	      if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
@@ -3443,7 +3448,7 @@ build_conditional_expr (ifexp, op1, op2)
     }
   else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
     {
-      if (comp_target_types (type1, type2))
+      if (comp_target_types (type1, type2, 1))
 	result_type = common_type (type1, type2);
       else if (integer_zerop (op1) && TREE_TYPE (type1) == void_type_node
 	       && TREE_CODE (orig_op1) != NOP_EXPR)
@@ -4010,8 +4015,9 @@ convert_for_assignment (type, rhs, errtype, fundecl, funname, parmnum)
   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
     {
       overflow_warning (rhs);
-      /* Check for Objective-C protocols.  This will issue a warning if
-	 there are protocol violations.  No need to use the return value.  */
+      /* Check for Objective-C protocols.  This will automatically
+	 issue a warning if there are protocol violations.  No need to
+	 use the return value.  */
       if (flag_objc)
 	objc_comptypes (type, rhstype, 0);
       return rhs;
@@ -4086,7 +4092,7 @@ convert_for_assignment (type, rhs, errtype, fundecl, funname, parmnum)
 		 Meanwhile, the lhs target must have all the qualifiers of
 		 the rhs.  */
 	      if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
-		  || comp_target_types (memb_type, rhstype))
+		  || comp_target_types (memb_type, rhstype, 0))
 		{
 		  /* If this type won't generate any warnings, use it.  */
 		  if (TYPE_QUALS (ttl) == TYPE_QUALS (ttr)
@@ -4161,7 +4167,7 @@ convert_for_assignment (type, rhs, errtype, fundecl, funname, parmnum)
 	 and vice versa; otherwise, targets must be the same.
 	 Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
-	  || comp_target_types (type, rhstype)
+	  || comp_target_types (type, rhstype, 0)
 	  || (c_common_unsigned_type (TYPE_MAIN_VARIANT (ttl))
 	      == c_common_unsigned_type (TYPE_MAIN_VARIANT (ttr))))
 	{
@@ -4186,7 +4192,7 @@ convert_for_assignment (type, rhs, errtype, fundecl, funname, parmnum)
 	      /* If this is not a case of ignoring a mismatch in signedness,
 		 no warning.  */
 	      else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
-		       || comp_target_types (type, rhstype))
+		       || comp_target_types (type, rhstype, 0))
 		;
 	      /* If there is a mismatch, do warn.  */
 	      else if (pedantic)

gcc/objc/objc-act.c

@@ -587,10 +587,24 @@ lookup_protocol_in_reflist (rproto_list, lproto)
   return 0;
 }
 
-/* Return 1 if LHS and RHS are compatible types for assignment
-   or various other operations.  Return 0 if they are incompatible,
-   and return -1 if we choose to not decide.  When the operation
-   is REFLEXIVE, check for compatibility in either direction.  */
+/* Return 1 if LHS and RHS are compatible types for assignment or
+   various other operations.  Return 0 if they are incompatible, and
+   return -1 if we choose to not decide (because the types are really
+   just C types, not ObjC specific ones).  When the operation is
+   REFLEXIVE (typically comparisons), check for compatibility in
+   either direction; when it's not (typically assignments), don't.
+
+   This function is called in two cases: when both lhs and rhs are
+   pointers to records (in which case we check protocols too), and
+   when both lhs and rhs are records (in which case we check class
+   inheritance only).
+
+   Warnings about classes/protocols not implementing a protocol are
+   emitted here (multiple of those warnings might be emitted for a
+   single line!); generic warnings about incompatible assignments and
+   lacks of casts in comparisons are/must be emitted by the caller if
+   we return 0.
+*/
 
 int
 objc_comptypes (lhs, rhs, reflexive)
@@ -600,6 +614,8 @@ objc_comptypes (lhs, rhs, reflexive)
 {
   /* New clause for protocols.  */
 
+  /* Here we manage the case of a POINTER_TYPE = POINTER_TYPE.  We only
+     manage the ObjC ones, and leave the rest to the C code.  */
   if (TREE_CODE (lhs) == POINTER_TYPE
       && TREE_CODE (TREE_TYPE (lhs)) == RECORD_TYPE
       && TREE_CODE (rhs) == POINTER_TYPE
@@ -614,29 +630,75 @@ objc_comptypes (lhs, rhs, reflexive)
 	  tree rproto, rproto_list;
 	  tree p;
 
+	  /* <Protocol> = <Protocol>  */
 	  if (rhs_is_proto)
 	    {
 	      rproto_list = TYPE_PROTOCOL_LIST (rhs);
-
-	      /* Make sure the protocol is supported by the object
-		 on the rhs.  */
-	      for (lproto = lproto_list; lproto; lproto = TREE_CHAIN (lproto))
+	      
+	      if (!reflexive)
 		{
-		  p = TREE_VALUE (lproto);
-		  rproto = lookup_protocol_in_reflist (rproto_list, p);
+		  /* An assignment between objects of type 'id
+		     <Protocol>'; make sure the protocol on the lhs is
+		     supported by the object on the rhs.  */
+		  for (lproto = lproto_list; lproto; 
+		       lproto = TREE_CHAIN (lproto))
+		    {
+		      p = TREE_VALUE (lproto);
+		      rproto = lookup_protocol_in_reflist (rproto_list, p);
 
-		  if (!rproto)
-		    warning ("object does not conform to the `%s' protocol",
-			     IDENTIFIER_POINTER (PROTOCOL_NAME (p)));
+		      if (!rproto)
+			warning 
+			  ("object does not conform to the `%s' protocol",
+			   IDENTIFIER_POINTER (PROTOCOL_NAME (p)));
+		    }
+		  return 1;
+		}
+	      else
+		{
+		  /* Obscure case - a comparison between two objects
+		     of type 'id <Protocol>'.  Check that either the
+		     protocol on the lhs is supported by the object on
+		     the rhs, or viceversa.  */
+		  
+		  /* Check if the protocol on the lhs is supported by the
+		     object on the rhs.  */
+		  for (lproto = lproto_list; lproto; 
+		       lproto = TREE_CHAIN (lproto))
+		    {
+		      p = TREE_VALUE (lproto);
+		      rproto = lookup_protocol_in_reflist (rproto_list, p);
+		      
+		      if (!rproto)
+			{
+			  /* Check failed - check if the protocol on the rhs
+			     is supported by the object on the lhs.  */
+			  for (rproto = rproto_list; rproto; 
+			       rproto = TREE_CHAIN (rproto))
+			    {
+			      p = TREE_VALUE (rproto);
+			      lproto = lookup_protocol_in_reflist (lproto_list,
+								   p);
+
+			      if (!lproto)
+				{
+				  /* This check failed too: incompatible  */
+				  return 0;
+				}
+			    }
+			  return 1;
+			}
+		    }
+		  return 1;
 		}
 	    }
+	  /* <Protocol> = <class> *  */
 	  else if (TYPED_OBJECT (TREE_TYPE (rhs)))
 	    {
 	      tree rname = TYPE_NAME (TREE_TYPE (rhs));
 	      tree rinter;
 
-	      /* Make sure the protocol is supported by the object
-		 on the rhs.  */
+	      /* Make sure the protocol is supported by the object on
+		 the rhs.  */
 	      for (lproto = lproto_list; lproto; lproto = TREE_CHAIN (lproto))
 		{
 		  p = TREE_VALUE (lproto);
@@ -651,7 +713,7 @@ objc_comptypes (lhs, rhs, reflexive)
 		      rproto = lookup_protocol_in_reflist (rproto_list, p);
 		      /* If the underlying ObjC class does not have
 			 the protocol we're looking for, check for "one-off"
-			 protocols (e.g., `NSObject<MyProt> foo;') attached
+			 protocols (e.g., `NSObject<MyProt> *foo;') attached
 			 to the rhs.  */
 		      if (!rproto)
 			{
@@ -665,7 +727,6 @@ objc_comptypes (lhs, rhs, reflexive)
 			{
 			  rproto_list = CLASS_PROTOCOL_LIST (cat);
 			  rproto = lookup_protocol_in_reflist (rproto_list, p);
-
 			  cat = CLASS_CATEGORY_LIST (cat);
 			}
 
@@ -674,31 +735,127 @@ objc_comptypes (lhs, rhs, reflexive)
 
 		  if (!rproto)
 		    warning ("class `%s' does not implement the `%s' protocol",
-	                     IDENTIFIER_POINTER (TYPE_NAME (TREE_TYPE (rhs))),
-		             IDENTIFIER_POINTER (PROTOCOL_NAME (p)));
+			     IDENTIFIER_POINTER (TYPE_NAME (TREE_TYPE (rhs))),
+			     IDENTIFIER_POINTER (PROTOCOL_NAME (p)));
 		}
+	      return 1;
 	    }
-
-	  /* May change...based on whether there was any mismatch */
-          return 1;
+	  /* <Protocol> = id */
+	  else if (TYPE_NAME (TREE_TYPE (rhs)) == objc_object_id)
+	    {
+	      return 1;
+	    }
+	  /* <Protocol> = Class */
+	  else if (TYPE_NAME (TREE_TYPE (rhs)) == objc_class_id)
+	    {
+	      return 0;
+	    }
+	  /* <Protocol> = ?? : let comptypes decide.  */
+          return -1;
         }
       else if (rhs_is_proto)
-	/* Lhs is not a protocol...warn if it is statically typed */
-	return (TYPED_OBJECT (TREE_TYPE (lhs)) != 0);
+	{
+	  /* <class> * = <Protocol> */
+	  if (TYPED_OBJECT (TREE_TYPE (lhs)))
+	    {
+	      if (reflexive)
+		{
+		  tree rname = TYPE_NAME (TREE_TYPE (lhs));
+		  tree rinter;
+		  tree rproto, rproto_list = TYPE_PROTOCOL_LIST (rhs);
+		  
+		  /* Make sure the protocol is supported by the object on
+		     the lhs.  */
+		  for (rproto = rproto_list; rproto; 
+		       rproto = TREE_CHAIN (rproto))
+		    {
+		      tree p = TREE_VALUE (rproto);
+		      tree lproto = 0;
+		      rinter = lookup_interface (rname);
 
+		      while (rinter && !lproto)
+			{
+			  tree cat;
+
+			  tree lproto_list = CLASS_PROTOCOL_LIST (rinter);
+			  lproto = lookup_protocol_in_reflist (lproto_list, p);
+			  /* If the underlying ObjC class does not
+			     have the protocol we're looking for,
+			     check for "one-off" protocols (e.g.,
+			     `NSObject<MyProt> *foo;') attached to the
+			     lhs.  */
+			  if (!lproto)
+			    {
+			      lproto_list = TYPE_PROTOCOL_LIST 
+				(TREE_TYPE (lhs));
+			      lproto = lookup_protocol_in_reflist 
+				(lproto_list, p);
+			    }
+
+			  /* Check for protocols adopted by categories.  */
+			  cat = CLASS_CATEGORY_LIST (rinter);
+			  while (cat && !lproto)
+			    {
+			      lproto_list = CLASS_PROTOCOL_LIST (cat);
+			      lproto = lookup_protocol_in_reflist (lproto_list,
+								   p);
+			      cat = CLASS_CATEGORY_LIST (cat);
+			    }
+			  
+			  rinter = lookup_interface (CLASS_SUPER_NAME 
+						     (rinter));
+			}
+		      
+		      if (!lproto)
+			warning ("class `%s' does not implement the `%s' protocol",
+				 IDENTIFIER_POINTER (TYPE_NAME 
+						     (TREE_TYPE (lhs))),
+				 IDENTIFIER_POINTER (PROTOCOL_NAME (p)));
+		    }
+		  return 1;
+		}
+	      else
+		return 0;
+	    }
+	  /* id = <Protocol> */
+	  else if (TYPE_NAME (TREE_TYPE (lhs)) == objc_object_id)
+	    {
+	      return 1;
+	    }
+	  /* Class = <Protocol> */
+	  else if (TYPE_NAME (TREE_TYPE (lhs)) == objc_class_id)
+	    {
+	      return 0;
+	    }
+	  /* ??? = <Protocol> : let comptypes decide */
+	  else
+	    {
+	      return -1;
+	    }
+	}
       else
-	/* Defer to comptypes.  */
-	return -1;
+	{
+	  /* Attention: we shouldn't defer to comptypes here.  One bad
+	     side effect would be that we might loose the REFLEXIVE
+	     information.
+	  */
+	  lhs = TREE_TYPE (lhs);
+	  rhs = TREE_TYPE (rhs);
+	}
     }
 
-  else if (TREE_CODE (lhs) == RECORD_TYPE && TREE_CODE (rhs) == RECORD_TYPE)
-    ; /* Fall thru.  This is the case we have been handling all along */
-  else
-    /* Defer to comptypes.  */
-    return -1;
-
-  /* `id' = `<class> *', `<class> *' = `id' */
+  if (TREE_CODE (lhs) != RECORD_TYPE || TREE_CODE (rhs) != RECORD_TYPE)
+    {
+      /* Nothing to do with ObjC - let immediately comptypes take
+	 responsibility for checking.  */
+      return -1;
+    }
 
+  /* `id' = `<class> *' `<class> *' = `id': always allow it.
+     Please note that 
+     'Object *o = [[Object alloc] init]; falls
+     in the case <class> * = `id'.
+  */
   if ((TYPE_NAME (lhs) == objc_object_id && TYPED_OBJECT (rhs))
       || (TYPE_NAME (rhs) == objc_object_id && TYPED_OBJECT (lhs)))
     return 1;
@@ -739,7 +896,7 @@ objc_comptypes (lhs, rhs, reflexive)
       return 0;
     }
   else
-    /* Defer to comptypes.  */
+    /* Not an ObjC type - let comptypes do the check.  */
     return -1;
 }