Improve --help output to generate references to option aliases.

gcc/
	PR driver/68043
	* opts.c (undocumented_msg, use_diagnosed_msg): New globals.
	(print_filtered_help): Reference aliased option's name and encourage
	readers to use it in preference to the alias if the former is not
	documented.  Mention when using an option is diagnosed.
	* gcc.c (display_help): End each sentence with a period.

	* ada/gcc-interface/lang.opt: End each sentence that describes
	an option with a period.
	* c-family/c.opt: Same.
	* common.opt: Same.
	* config/aarch64/aarch64.opt: Same.
	* config/alpha/alpha.opt: Same.
	* config/arc/arc.opt: Same.
	* config/arm/arm.opt: Same.
	* config/avr/avr.opt: Same.
	* config/bfin/bfin.opt: Same.
	* config/c6x/c6x.opt: Same.
	* config/cr16/cr16.opt: Same.
	* config/cris/cris.opt: Same.
	* config/cris/linux.opt: Same.
	* config/darwin.opt: Same.
	* config/epiphany/epiphany.opt: Same.
	* config/fr30/fr30.opt: Same.
	* config/frv/frv.opt: Same.
	* config/ft32/ft32.opt: Same.
	* config/g.opt: Same.
	* config/h8300/h8300.opt: Same.
	* config/i386/cygming.opt: Same.
	* config/i386/djgpp.opt: Same.
	* config/i386/i386.opt: Same.
	* config/i386/interix.opt: Same.
	* config/i386/mingw-w64.opt: Same.
	* config/i386/mingw.opt: Same.
	* config/ia64/ia64.opt: Same.
	* config/ia64/ilp32.opt: Same.
	* config/iq2000/iq2000.opt: Same.
	* config/linux.opt: Same.
	* config/lm32/lm32.opt: Same.
	* config/lynx.opt: Same.
	* config/m32c/m32c.opt: Same.
	* config/m32r/m32r.opt: Same.
	* config/m68k/ieee.opt: Same.
	* config/m68k/m68k.opt: Same.
	* config/mcore/mcore.opt: Same.
	* config/mep/mep.opt: Same.
	* config/microblaze/microblaze.opt: Same.
	* config/mips/mips.opt: Same.
	* config/mmix/mmix.opt: Same.
	* config/mn10300/mn10300.opt: Same.
	* config/moxie/moxie.opt: Same.
	* config/msp430/msp430.opt: Same.
	* config/nios2/elf.opt: Same.
	* config/nios2/nios2.opt: Same.
	* config/nvptx/nvptx.opt: Same.
	* config/pa/pa-hpux.opt: Same.
	* config/pa/pa-hpux1010.opt: Same.
	* config/pa/pa-hpux1111.opt: Same.
	* config/pa/pa-hpux1131.opt: Same.
	* config/pa/pa.opt: Same.
	* config/pa/pa64-hpux.opt: Same.
	* config/pdp11/pdp11.opt: Same.
	* config/rl78/rl78.opt: Same.
	* config/rs6000/476.opt: Same.
	* config/rs6000/aix64.opt: Same.
	* config/rs6000/darwin.opt: Same.
	* config/rs6000/linux64.opt: Same.
	* config/rs6000/rs6000.opt: Same.
	* config/rs6000/sysv4.opt: Same.
	* config/s390/s390.opt: Same.
	* config/s390/tpf.opt: Same.
	* config/sh/sh.opt: Same.
	* config/sol2.opt: Same.
	* config/sparc/long-double-switch.opt: Same.
	* config/sparc/sparc.opt: Same.
	* config/spu/spu.opt: Same.
	* config/stormy16/stormy16.opt: Same.
	* config/tilegx/tilegx.opt: Same.
	* config/tilepro/tilepro.opt: Same.
	* config/v850/v850.opt: Same.
	* config/vax/vax.opt: Same.
	* config/visium/visium.opt: Same.
	* config/vms/vms.opt: Same.
	* config/vxworks.opt: Same.
	* config/xtensa/xtensa.opt: Same.
	* fortran/lang.opt: Same.

testsuite/
	PR driver/68043
	* gcc.misc-tests/help.exp: Adjust.
	* lib/options.exp (check_for_options): Add detail to output.

From-SVN: r229155

1 files changed, 43 insertions, 3 deletions

diff --git a/gcc/opts.c b/gcc/opts.c
index a892c88..9a3fbb3 100644
--- a/gcc/opts.c
+++ b/gcc/opts.c
@@ -181,7 +181,8 @@ base_of_path (const char *path, const char **base_out)
 }
 
 /* What to print when a switch has no documentation.  */
-static const char undocumented_msg[] = N_("This switch lacks documentation");
+static const char undocumented_msg[] = N_("This option lacks documentation.");
+static const char use_diagnosed_msg[] = N_("Uses of this option are diagnosed.");
 
 typedef char *char_p; /* For DEF_VEC_P.  */
 
@@ -1012,7 +1013,7 @@ print_filtered_help (unsigned int include_flags,
   const char *help;
   bool found = false;
   bool displayed = false;
-  char new_help[128];
+  char new_help[256];
 
   if (include_flags == CL_PARAMS)
     {
@@ -1088,9 +1089,48 @@ print_filtered_help (unsigned int include_flags,
 	{
 	  if (exclude_flags & CL_UNDOCUMENTED)
 	    continue;
+
 	  help = undocumented_msg;
 	}
 
+      if (option->alias_target < N_OPTS
+	  && cl_options [option->alias_target].help)
+	{
+	  if (help == undocumented_msg)
+	    {
+	      /* For undocumented options that are aliases for other options
+		 that are documented, point the reader to the other option in
+		 preference of the former.  */
+	      snprintf (new_help, sizeof new_help,
+			_("Same as %s.  Use the latter option instead."),
+			cl_options [option->alias_target].opt_text);
+	    }
+	  else
+	    {
+	      /* For documented options with aliases, mention the aliased
+		 option's name for reference.  */
+	      snprintf (new_help, sizeof new_help,
+			_("%s  Same as %s."),
+			help, cl_options [option->alias_target].opt_text);
+	    }
+
+	  help = new_help;
+	}
+
+      if (option->warn_message)
+	{
+	  /* Mention that the use of the option will trigger a warning.  */
+	  if (help == new_help)
+	    snprintf (new_help + strlen (new_help),
+		      sizeof new_help - strlen (new_help),
+		      "  %s", _(use_diagnosed_msg));
+	  else
+	    snprintf (new_help, sizeof new_help,
+		      "%s  %s", help, _(use_diagnosed_msg));
+
+	  help = new_help;
+	}
+
       /* Get the translation.  */
       help = _(help);
 
@@ -1180,7 +1220,7 @@ print_filtered_help (unsigned int include_flags,
 	     options supported by a specific front end.  */
 	  for (i = 0; (1U << i) < CL_LANG_ALL; i ++)
 	    if ((1U << i) & langs)
-	      printf (_(" None found.  Use --help=%s to show *all* the options supported by the %s front-end\n"),
+	      printf (_(" None found.  Use --help=%s to show *all* the options supported by the %s front-end.\n"),
 		      lang_names[i], lang_names[i]);
 	}