Update ObjC constant string handling

[Stan Shebs <shebs at apple dot com>]

This patch fixes ObjC to do the right thing for @"..." constructs
when -fnext-runtime, which is basically to lay down some globals
that the NeXT^H^H^H^HDarwin runtime knows how to process.  This
has no effect if -fgnu-runtime.  Tested on powerpc-apple-darwin1.3,
committed to mainline only.

Stan

2001-05-02  Stan Shebs  <shebs@apple.com>

        * objc/objc-act.c (STRING_OBJECT_CLASS_NAME): Default to
        NSConstantString for NeXT-style runtimes.
        (STRING_OBJECT_GLOBAL_NAME): New macro.
        (enum objc_tree_index): Add values OCTI_CNST_STR_GLOB_ID and
        OCTI_STRING_CLASS_DECL.
        (constant_string_global_id): New macro.
        (string_class_decl): Ditto.
        (setup_string_decl): New function.
        (build_objc_string_object): Use it to build a NeXT runtime
        compatible string initializer.

Index: objc/objc-act.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/objc/objc-act.c,v
retrieving revision 1.79
diff -c -3 -p -r1.79 objc-act.c
*** objc-act.c	2001/05/01 20:45:55	1.79
--- objc-act.c	2001/05/02 21:43:53
*************** static tree lookup_method_in_protocol_li
*** 289,294 ****
--- 289,295 ----
  static tree lookup_protocol_in_reflist		PARAMS ((tree, tree));
  static tree create_builtin_decl			PARAMS ((enum tree_code,
  						       tree, const char *));
+ static void setup_string_decl			PARAMS ((void));
  static tree my_build_string			PARAMS ((int, const char *));
  static void build_objc_symtab_template		PARAMS ((void));
  static tree init_def_list			PARAMS ((tree));
*************** static void ggc_mark_hash_table			PARAMS
*** 375,381 ****
--- 376,390 ----
  #define UTAG_METHOD_PROTOTYPE	"_objc_method_prototype"
  #define UTAG_METHOD_PROTOTYPE_LIST "_objc__method_prototype_list"
  
+ #ifdef NEXT_OBJC_RUNTIME
+ #define STRING_OBJECT_CLASS_NAME "NSConstantString"
+ #else
  #define STRING_OBJECT_CLASS_NAME "NXConstantString"
+ #endif
+ /* Note that the string object global name is only needed for the
+    NeXT runtime.  */
+ #define STRING_OBJECT_GLOBAL_NAME "_NSConstantStringClassReference"
+ 
  #define PROTOCOL_OBJECT_CLASS_NAME "Protocol"
  
  static const char *constant_string_class_name = NULL;
*************** enum objc_tree_index
*** 455,460 ****
--- 464,471 ----
      OCTI_ID_ID,
      OCTI_CNST_STR_ID,
      OCTI_CNST_STR_TYPE,
+     OCTI_CNST_STR_GLOB_ID,
+     OCTI_STRING_CLASS_DECL,
      OCTI_SUPER_DECL,
      OCTI_METH_CTX,
  
*************** static int cat_count = 0;	/* `@category'
*** 576,581 ****
--- 587,594 ----
  #define objc_id_id		objc_global_trees[OCTI_ID_ID]
  #define constant_string_id	objc_global_trees[OCTI_CNST_STR_ID]
  #define constant_string_type	objc_global_trees[OCTI_CNST_STR_TYPE]
+ #define constant_string_global_id  objc_global_trees[OCTI_CNST_STR_GLOB_ID]
+ #define string_class_decl	objc_global_trees[OCTI_STRING_CLASS_DECL]
  #define UOBJC_SUPER_decl	objc_global_trees[OCTI_SUPER_DECL]
  
  #define method_context		objc_global_trees[OCTI_METH_CTX]
*************** create_builtin_decl (code, type, name)
*** 1243,1248 ****
--- 1256,1279 ----
    return decl;
  }
  
+ /* Find the decl for the constant string class.  */
+ 
+ static void
+ setup_string_decl ()
+ {
+   if (!string_class_decl)
+     {
+       if (!constant_string_global_id)
+ 	{
+ 	  constant_string_global_id =
+ 	    get_identifier (STRING_OBJECT_GLOBAL_NAME);
+ 	  if (constant_string_global_id == NULL_TREE)
+ 	    return;
+         }
+       string_class_decl = lookup_name (constant_string_global_id);
+     }
+ }
+ 
  /* Purpose: "play" parser, creating/installing representations
     of the declarations that are required by Objective-C.
  
*************** build_objc_string_object (strings)
*** 1431,1438 ****
    length = TREE_STRING_LENGTH (string) - 1;
  
    /* & ((NXConstantString) {0, string, length})  */
  
-   initlist = build_tree_list (NULL_TREE, build_int_2 (0, 0));
    initlist
      = tree_cons (NULL_TREE, copy_node (build_unary_op (ADDR_EXPR, string, 1)),
  		 initlist);
--- 1462,1488 ----
    length = TREE_STRING_LENGTH (string) - 1;
  
    /* & ((NXConstantString) {0, string, length})  */
+ 
+   if (flag_next_runtime)
+     {
+       /* For the NeXT runtime, we can generate a literal reference
+ 	 to the string class, don't need to run a constructor.  */
+       setup_string_decl ();
+       if (string_class_decl == NULL_TREE)
+ 	{
+ 	  error ("Cannot find reference tag for class `%s'",
+ 		 IDENTIFIER_POINTER (constant_string_id));
+ 	  return error_mark_node;
+ 	}
+       initlist = build_tree_list
+ 	(NULL_TREE,
+ 	 copy_node (build_unary_op (ADDR_EXPR, string_class_decl, 0)));
+     }
+   else
+     {
+       initlist = build_tree_list (NULL_TREE, build_int_2 (0, 0));
+     }
  
    initlist
      = tree_cons (NULL_TREE, copy_node (build_unary_op (ADDR_EXPR, string, 1)),
  		 initlist);