Patch to implement -Wunknown-pragmas

Patch to implement -Wunknown-pragmas

[Nick Clifton]

After all the discussion, here is the patch to implement the
-Wunknown-pragmas warning:

gcc/ChangeLog:
Mon Oct 20 10:43:15 1997  Nick Clifton  <nickc@cygnus.com>

	* c-pragma.c (handle_pragma_token): Generate warning messages
	about unknown pragmas if warn_unknown_pragmas is set.

	* c-decl.c (c_decode_option): Parse -Wunknown-pragmas command
	line option to set variable: warn_unknown_pragmas.

	* invoke.texi (Warning Options): Document -Wunknown-pragmas
	command line option.

gcc/cp/ChangeLog:
Mon Oct 20 10:36:44 1997  Nick Clifton  <nickc@cygnus.com>

	* decl2.c (lang_decode_option): Add support for command line
	option: -Wunknown-pragmas.



Index: invoke.texi
===================================================================
RCS file: /cvs/cvsfiles/devo/gcc/invoke.texi,v
retrieving revision 1.218
diff -p -r1.218 invoke.texi
*** invoke.texi	1997/10/17 00:13:56	1.218
--- invoke.texi	1997/10/20 21:22:39
*************** in the following sections.
*** 130,135 ****
--- 130,136 ----
  -Wsign-compare  -Wstrict-prototypes  -Wswitch  -Wsynth
  -Wtemplate-debugging  -Wtraditional  -Wtrigraphs
  -Wundef  -Wuninitialized  -Wunused  -Wwrite-strings
+ -Wunknown-pragmas
  @end smallexample
  
  @item Debugging Options
*************** an incorrect result when the signed valu
*** 1440,1445 ****
--- 1441,1455 ----
  @cindex template debugging
  When using templates in a C++ program, warn if debugging is not yet
  fully available (C++ only).
+ 
+ @item -Wunknown-pragmas
+ @cindex warning for unknown pragmas
+ @cindex unknown pragmas, warning
+ @cindex pragmas, warning of unknown
+ Warn when a #pragma directive is encountered which is not understood by
+ GCC.  If this command line option is used, warnings will even be issued
+ for unknown pragmas in system header files.  This is not the case if
+ the warnings were only enabled by the @samp{-Wall} command line option.
  
  @item -Wall
  All of the above @samp{-W} options combined.  This enables all the


Index: c-decl.c
===================================================================
RCS file: /cvs/cvsfiles/devo/gcc/c-decl.c,v
retrieving revision 1.191
retrieving revision 1.193
diff -p -r1.191 -r1.193
*** c-decl.c	1997/10/14 00:49:15	1.191
--- c-decl.c	1997/10/20 17:42:48	1.193
*************** int warn_main;
*** 557,562 ****
--- 557,566 ----
  
  int warn_sign_compare;
  
+ /* Warn about #pragma directives that are not recognised.  */
+ 
+ int warn_unknown_pragmas = 0; /* Tri state variable.  */
+ 
  /* Nonzero means `$' can be in an identifier.  */
  
  #ifndef DOLLARS_IN_IDENTIFIERS
*************** c_decode_option (p)
*** 743,748 ****
--- 747,758 ----
      warn_sign_compare = 1;
    else if (!strcmp (p, "-Wno-sign-compare"))
      warn_sign_compare = 0;
+   else if (!strcmp (p, "-Wunknown-pragmas"))
+     /* Set to greater than 1, so that even unknown pragmas in system
+        headers will be warned about.  */
+     warn_unknown_pragmas = 2;
+   else if (!strcmp (p, "-Wno-unknown-pragmas"))
+     warn_unknown_pragmas = 0;
    else if (!strcmp (p, "-Wall"))
      {
        /* We save the value of warn_uninitialized, since if they put
*************** c_decode_option (p)
*** 762,767 ****
--- 772,779 ----
        /* We set this to 2 here, but 1 in -Wmain, so -ffreestanding can turn
  	 it off only if it's not explicit.  */
        warn_main = 2;
+       /* Only warn about unknown pragmas that are not in system headers.  */
+       warn_unknown_pragmas = 1;
      }
    else
      return 0;


Index: decl2.c
===================================================================
RCS file: /cvs/cvsfiles/devo/gcc/cp/decl2.c,v
retrieving revision 1.345
retrieving revision 1.347
diff -p -r1.345 -r1.347
*** decl2.c	1997/10/14 20:34:45	1.345
--- decl2.c	1997/10/20 17:43:59	1.347
*************** int warn_sign_promo;
*** 271,276 ****
--- 271,280 ----
  
  int warn_old_style_cast;
  
+ /* Warn about #pragma directives that are not recognised.  */
+ 
+ int warn_unknown_pragmas = 0; /* Tri state variable.  */
+ 
  /* Nonzero means `$' can be in an identifier.  */
  
  #ifndef DOLLARS_IN_IDENTIFIERS
*************** lang_decode_option (p)
*** 670,675 ****
--- 674,683 ----
  	warn_sign_promo = setting;
        else if (!strcmp (p, "old-style-cast"))
  	warn_old_style_cast = setting;
+       else if (!strcmp (p, "unknown-pragmas"))
+ 	/* Set to greater than 1, so that even unknown pragmas in
+ 	   system headers will be warned about.  */
+ 	warn_unknown_pragmas = setting * 2; 
        else if (!strcmp (p, "comment"))
  	;			/* cpp handles this one.  */
        else if (!strcmp (p, "comments"))
*************** lang_decode_option (p)
*** 699,704 ****
--- 707,715 ----
  	  warn_template_debugging = setting;
  	  warn_reorder = setting;
  	  warn_sign_promo = setting;
+ 	  /* Only warn about unknown pragmas that are not in system
+ 	     headers.  */
+ 	  warn_unknown_pragmas = 1;
  	}
  
        else if (!strcmp (p, "overloaded-virtual"))


Index: c-pragma.c
===================================================================
RCS file: /cvs/cvsfiles/devo/gcc/c-pragma.c,v
retrieving revision 1.23
retrieving revision 1.25
diff -p -r1.23 -r1.25
*** c-pragma.c	1997/10/16 00:44:31	1.23
--- c-pragma.c	1997/10/20 17:42:54	1.25
*************** Boston, MA 02111-1307, USA.  */
*** 26,31 ****
--- 26,33 ----
  #include "defaults.h"
  #include "c-pragma.h"
  
+ #include "flags.h"  /* For the definition of in_system_header.  */
+ 
  #ifdef HANDLE_SYSV_PRAGMA
  
  /* When structure field packing is in effect, this variable is the
*************** extern FILE *asm_out_file;
*** 42,47 ****
--- 44,50 ----
  
  extern FILE * attr_info_file;
  extern int    flag_depragmaize; /* True if we are performing a depragmatization.  */
+ extern int    warn_unknown_pragmas;
  				   
  /* Tracks the current data area set by the data area pragma (which 
     can be nested).  Tested by check_default_data_area. */
*************** handle_pragma_token (string, token)
*** 402,407 ****
--- 405,416 ----
  	  else
  	    {
  	      type = state = ps_done;
+ 	      /* Issue a warning message if we have been asked to do so.
+ 		 Ignoring unknown pragmas in system header file unless
+ 		 an explcit -Wunknown-pragmas has been given.
+ 	      if (warn_unknown_pragmas > 1
+ 		  || (warn_unknown_pragmas && ! in_system_header))
+ 		warning ("ignoring pragma: %s", string );
  	    }
  	}
        else

Re: Patch to implement -Wunknown-pragmas

[Jeffrey A Law]

  In message <199710202210.PAA00478@elmo.cygnus.com>you write:
  > After all the discussion, here is the patch to implement the
  > -Wunknown-pragmas warning:
  > 
  > gcc/ChangeLog:
  > Mon Oct 20 10:43:15 1997  Nick Clifton  <nickc@cygnus.com>
  > 
  > 	* c-pragma.c (handle_pragma_token): Generate warning messages
  > 	about unknown pragmas if warn_unknown_pragmas is set.
  > 
  > 	* c-decl.c (c_decode_option): Parse -Wunknown-pragmas command
  > 	line option to set variable: warn_unknown_pragmas.
  > 
  > 	* invoke.texi (Warning Options): Document -Wunknown-pragmas
  > 	command line option.
  > 
  > gcc/cp/ChangeLog:
  > Mon Oct 20 10:36:44 1997  Nick Clifton  <nickc@cygnus.com>
  > 
  > 	* decl2.c (lang_decode_option): Add support for command line
  > 	option: -Wunknown-pragmas.
Just a minor note, I put a decl of warn_unknown_pragmas into flags.h
and installed your patch.

jeff