slightly improved documention for plugin pragmas

[Basile STARYNKEVITCH <basile at starynkevitch dot net>]

Hello All,

The attached patch to trunk rev 154075 did bootstap, and added more documentation about pragmas provided by plugins.
http://gcc.gnu.org/ml/gcc-patches/2009-11/msg00197.html
http://gcc.gnu.org/ml/gcc-patches/2009-11/msg00371.html

Also, I added in the user documentation that attributes & pragmas can be provided by plugins.

############
gcc/ChangeLog:
2009-11-10  Basile Starynkevitch  <basile@starynkevitch.net>
	* doc/plugins.texi (Registering custom attributes): section
	renamed as (Registering custom attributes or pragmas).
	Mentions custom attributes & pragmas, and c_register_pragma, with
	a small example.
	* doc/cpp.texi (Pragmas): Mentions that plugins can provide their
	pragmas.
	* doc/extend.texi (Function Attributes): Mentions that plugin can
	provide their attributes.
############


Feel free to improve the English language. I can apply this documentation patch if someone gives me an OK.


Regards.

--
Basile STARYNKEVITCH         http://starynkevitch.net/Basile/
email: basile<at>starynkevitch<dot>net mobile: +33 6 8501 2359
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*** opinions {are only mines, sont seulement les miennes} ***

Index: gcc/doc/plugins.texi
===================================================================
--- gcc/doc/plugins.texi	(revision 154075)
+++ gcc/doc/plugins.texi	(working copy)
@@ -261,9 +261,10 @@ Such a structure is passed as the @code{user_data}
 init routine using @code{register_callback} with the
 @code{PLUGIN_INFO} pseudo-event and a null callback.
 
-@section Registering custom attributes
+@section Registering custom attributes or pragmas
 
-For analysis purposes it is useful to be able to add custom attributes.
+For analysis (or other) purposes it is useful to be able to add custom
+attributes or pragmas.
 
 The @code{PLUGIN_ATTRIBUTES} callback is called during attribute
 registration. Use the @code{register_attribute} function to register
@@ -295,6 +296,28 @@ register_attributes (void *event_data, void *data)
 @end smallexample
 
 
+The @code{PLUGIN_PRAGMAS} callback is called during pragmas
+registration. Use the @code{c_register_pragma} or
+@code{c_register_pragma_with_expansion} functions to register custom
+pragmas.
+
+@smallexample
+/* Plugin callback called during pragmas registration. Registered with
+     register_callback (plugin_name, PLUGIN_PRAGMAS,
+                        register_my_pragma, NULL);
+*/
+static void 
+register_my_pragma (void *event_data, void *data) 
+@{
+  warning (0, G_("Callback to register pragmas"));
+  c_register_pragma ("GCCPLUGIN", "sayhello", handle_pragma_sayhello);
+@}
+@end smallexample
+
+It is suggested to pass @code{"GCCPLUGIN"} (or a short name identifying
+your plugin) as the ``space'' argument of your pragma. 
+
+
 @section Building GCC plugins
 
 If plugins are enabled, GCC installs the headers needed to build a
Index: gcc/doc/cpp.texi
===================================================================
--- gcc/doc/cpp.texi	(revision 154075)
+++ gcc/doc/cpp.texi	(working copy)
@@ -3541,6 +3541,8 @@ This manual documents the pragmas which are meanin
 preprocessor itself.  Other pragmas are meaningful to the C or C++
 compilers.  They are documented in the GCC manual.
 
+GCC plugins may provide their own pragmas.
+
 @ftable @code
 @item #pragma GCC dependency
 @code{#pragma GCC dependency} allows you to check the relative dates of
Index: gcc/doc/extend.texi
===================================================================
--- gcc/doc/extend.texi	(revision 154075)
+++ gcc/doc/extend.texi	(working copy)
@@ -1922,6 +1922,8 @@ particular target systems.  Other attributes, incl
 are supported for variables declarations (@pxref{Variable Attributes})
 and for types (@pxref{Type Attributes}).
 
+GCC plugins may provide their own attributes.
+
 You may also specify attributes with @samp{__} preceding and following
 each keyword.  This allows you to use them in header files without
 being concerned about a possible macro of the same name.  For example,