extend.texi: Document C++ restricted pointers and references.

* extend.texi: Document C++ restricted pointers and references.

	* cp-tree.h (grok_method_quals): Return this pointer qualifiers.
	* decl.c (grokdeclarator): Adjust calls to grok_method_quals.
	* decl2.c (grok_method_quals): Accept `restrict' as applying to
	the object pointer. Return such qualifiers.
	(grokclassfn): Apply this pointer qualifiers. Cleanup unused
	variables.

From-SVN: r30587

gcc/ChangeLog

@@ -1,12 +1,17 @@
+Fri Nov 19 10:41:15 GMT 1999  Nathan Sidwell  <nathan@acm.org>
+
+	* extend.texi: Document C++ restricted pointers and references.	
+
 1999-11-19  Bernd Schmidt  <bernds@cygnus.co.uk>
 
 	* cse.c (addr_affects_sp): No longer conditional on AUTO_INC_DEC.
 	(invalidate_skipped_set): Call it unconditionally.
 	(cse_set_around_loop): Likewise.
 
-Fri Nov 18 13:39:22 CET 1999  Jam Hubicka  <hubicka@freesoft.cz>
+Fri Nov 18 13:39:22 CET 1999  Jan Hubicka  <hubicka@freesoft.cz>
-	* i386.h (struct_processor_costs): New fileds int_load, int_store, fp_move,
+
-	fp_load and fp_store
+	* i386.h (struct_processor_costs): New fileds int_load, int_store,
+	fp_move, fp_load and fp_store
 	(REGISTER_MOVE_COST): Fix comment, calculate exactly the cost of
 	fp->int moves
 	(MEMORY_MOVE_COST): New macro.

gcc/cp/ChangeLog

@@ -1,3 +1,12 @@
+1999-11-19  Nathan Sidwell  <nathan@acm.org>
+
+	* cp-tree.h (grok_method_quals): Return this pointer qualifiers.
+	* decl.c (grokdeclarator): Adjust calls to grok_method_quals.
+	* decl2.c (grok_method_quals): Accept `restrict' as applying to
+	the object pointer. Return such qualifiers.
+	(grokclassfn): Apply this pointer qualifiers. Cleanup unused
+	variables.
+
 1999-11-18  Mark Mitchell  <mark@codesourcery.com>
 
 	* except.c (expand_end_catch_block): Fix typo.

gcc/cp/cp-tree.h

@@ -3529,7 +3529,7 @@ extern void make_rtl_for_local_static           PROTO((tree));
 extern void init_decl2				PROTO((void));
 extern int check_java_method			PROTO((tree));
 extern int lang_decode_option			PROTO((int, char **));
-extern tree grok_method_quals			PROTO((tree, tree, tree));
+extern int grok_method_quals			PROTO((tree, tree, tree));
 extern void warn_if_unknown_interface		PROTO((tree));
 extern void grok_x_components			PROTO((tree));
 extern void maybe_retrofit_in_chrg		PROTO((tree));

gcc/cp/decl.c

@@ -8919,7 +8919,8 @@ create_array_type_for_decl (name, type, size)
    is erroneous, NULL_TREE is returned.
 
    QUALS is used only for FUNCDEF and MEMFUNCDEF cases.  For a member
-   function, these are the qualifiers to give to the `this' pointer.
+   function, these are the qualifiers to give to the `this' pointer. We
+   apply TYPE_QUAL_RESTRICT to the this ptr, not the object.
 
    May return void_type_node if the declarator turned out to be a friend.
    See grokfield for details.  */
@@ -9836,8 +9837,9 @@ grokdeclarator (declarator, declspecs, decl_context, initialized, attrlist)
 	  if (ctype != NULL_TREE)
 	    {
 	      tree dummy = build_decl (TYPE_DECL, NULL_TREE, type);
-	      ctype = grok_method_quals (ctype, dummy, quals);
+	      grok_method_quals (ctype, dummy, quals);
 	      type = TREE_TYPE (dummy);
+	      ctype = TREE_TYPE (TREE_VALUE (TYPE_ARG_TYPES (type)));
 	      quals = NULL_TREE;
 	    }
 	}

gcc/cp/decl2.c

@@ -780,9 +780,11 @@ lang_decode_option (argc, argv)
 
 /* Incorporate `const' and `volatile' qualifiers for member functions.
    FUNCTION is a TYPE_DECL or a FUNCTION_DECL.
-   QUALS is a list of qualifiers.  */
+   QUALS is a list of qualifiers.  Returns any explicit
+   top-level qualifiers of the method's this pointer, anything other than
+   TYPE_UNQUALIFIED will be an extension.  */
 
-tree
+int
 grok_method_quals (ctype, function, quals)
      tree ctype, function, quals;
 {
@@ -790,13 +792,16 @@ grok_method_quals (ctype, function, quals)
   tree raises = TYPE_RAISES_EXCEPTIONS (fntype);
   int type_quals = TYPE_UNQUALIFIED;
   int dup_quals = TYPE_UNQUALIFIED;
+  int this_quals = TYPE_UNQUALIFIED;
 
   do
     {
       int tq = cp_type_qual_from_rid (TREE_VALUE (quals));
       
-      if (type_quals & tq)
+      if ((type_quals | this_quals) & tq)
 	dup_quals |= tq;
+      else if (tq & TYPE_QUAL_RESTRICT)
+        this_quals |= tq;
       else
 	type_quals |= tq;
       quals = TREE_CHAIN (quals);
@@ -817,7 +822,7 @@ grok_method_quals (ctype, function, quals)
     fntype = build_exception_variant (fntype, raises);
 
   TREE_TYPE (function) = fntype;
-  return ctype;
+  return this_quals;
 }
 
 /* Warn when -fexternal-templates is used and #pragma
@@ -961,9 +966,7 @@ grokclassfn (ctype, function, flags, quals)
      tree quals;
 {
   tree fn_name = DECL_NAME (function);
-  tree arg_types;
+  int this_quals = TYPE_UNQUALIFIED;
-  tree parm;
-  tree qualtype;
 
   if (fn_name == NULL_TREE)
     {
@@ -973,26 +976,23 @@ grokclassfn (ctype, function, flags, quals)
     }
 
   if (quals)
-    qualtype = grok_method_quals (ctype, function, quals);
+    this_quals = grok_method_quals (ctype, function, quals);
-  else
-    qualtype = ctype;
 
-  arg_types = TYPE_ARG_TYPES (TREE_TYPE (function));
   if (TREE_CODE (TREE_TYPE (function)) == METHOD_TYPE)
     {
       /* Must add the class instance variable up front.  */
       /* Right now we just make this a pointer.  But later
 	 we may wish to make it special.  */
-      tree type = TREE_VALUE (arg_types);
+      tree type = TREE_VALUE (TYPE_ARG_TYPES (TREE_TYPE (function)));
 
-      parm = build_decl (PARM_DECL, this_identifier, type);
+      tree parm = build_decl (PARM_DECL, this_identifier,
+                         cp_build_qualified_type (type, this_quals | TYPE_QUAL_CONST));
       /* Mark the artificial `this' parameter as "artificial".  */
       SET_DECL_ARTIFICIAL (parm);
       DECL_ARG_TYPE (parm) = type;
       /* We can make this a register, so long as we don't
 	 accidentally complain if someone tries to take its address.  */
       DECL_REGISTER (parm) = 1;
-      TREE_READONLY (parm) = 1;
       TREE_CHAIN (parm) = last_function_parms;
       last_function_parms = parm;
     }
@@ -1003,10 +1003,7 @@ grokclassfn (ctype, function, flags, quals)
   DECL_CLASS_CONTEXT (function) = ctype;
 
   if (flags == DTOR_FLAG || DECL_CONSTRUCTOR_P (function))
-    {
+    maybe_retrofit_in_chrg (function);
-      maybe_retrofit_in_chrg (function);
-      arg_types = TYPE_ARG_TYPES (TREE_TYPE (function));
-    }
 
   if (flags == DTOR_FLAG)
     {

gcc/extend.texi

@@ -3219,6 +3219,7 @@ Predefined Macros,cpp.info,The C Preprocessor}).
 * Naming Results::      Giving a name to C++ function return values.
 * Min and Max::		C++ Minimum and maximum operators.
 * Volatiles::		What constitutes an access to a volatile object.
+* Restricted Pointers:: C9X restricted pointers and references.
 * C++ Interface::       You can use a single C++ header file for both
                          declarations and definitions.
 * Template Instantiation:: Methods for ensuring that exactly one copy of
@@ -3466,6 +3467,55 @@ possible to ignore the return value from functions returning volatile
 references. Again, if you wish to force a read, cast the reference to
 an rvalue.
 
+@node Restricted Pointers
+@section Restricting Pointer Aliasing
+@cindex restricted pointers
+@cindex restricted references
+@cindex restricted this pointer
+
+As with gcc, g++ understands the C9X proposal of restricted pointers,
+specified with the @code{__restrict__}, or @code{__restrict} type
+qualifier. Because you cannot compile C++ by specifying the -flang-isoc9x
+language flag, @code{restrict} is not a keyword in C++.
+
+In addition to allowing restricted pointers, you can specify restricted
+references, which indicate that the reference is not aliased in the local
+context.
+
+@example
+void fn (int *__restrict__ rptr, int &__restrict__ rref)
+@{
+  @dots{}
+@}
+@end example
+
+@noindent
+In the body of @code{fn}, @var{rptr} points to an unaliased integer and
+@var{rref} refers to a (different) unaliased integer.
+
+You may also specify whether a member function's @var{this} pointer is
+unaliased by using @code{__restrict__} as a member function qualifier.
+
+@example
+void T::fn () __restrict__
+@{
+  @dots{}
+@}
+@end example
+
+@noindent
+Within the body of @code{T::fn}, @var{this} will have the effective
+definition @code{T *__restrict__ const this}. Notice that the
+interpretation of a @code{__restrict__} member function qualifier is
+different to that of @code{const} or @code{volatile} qualifier, in that it
+is applied to the pointer rather than the object. This is consistent with
+other compilers which implement restricted pointers.
+
+As with all outermost parameter qualifiers, @code{__restrict__} is
+ignored in function definition matching. This means you only need to
+specify @code{__restrict__} in a function definition, rather than
+in a function prototype as well.
+
 @node C++ Interface
 @section Declarations and Definitions in One Header