common.opt (fwhopr=): Update for -fwhopr=jobserver

       * common.opt (fwhopr=): Update for -fwhopr=jobserver
       * doc/invoke.texi (fwhopr): Document -fwhopr=jobserver.
       * lto-wrapper.c (run_gcc): Add jobserver mode.
       * opts.c (common_handle_option): Fix OPT_fwhopr for non numeric
         argument.

From-SVN: r163680

gcc/ChangeLog

+2010-08-31  Andi Kleen      <ak@linux.intel.com>
+
+	* common.opt (fwhopr=): Update for -fwhopr=jobserver
+	* doc/invoke.texi (fwhopr): Document -fwhopr=jobserver.
+	* lto-wrapper.c (run_gcc): Add jobserver mode.
+	* opts.c (common_handle_option): Fix OPT_fwhopr for non numeric
+	argument.
+
 2010-08-31  Uros Bizjak  <ubizjak@gmail.com>
 
 	* config/i386/i386.md (popdi1): Rewrite using POST_INC memory operand.

gcc/common.opt

@@ -1579,8 +1579,8 @@ Common
 Enable partitioned link-time optimization
 
 fwhopr=
-Common RejectNegative UInteger Joined Var(flag_whopr)
-Enable partitioned link-time optimization with specified number of parallel jobs
+Common RejectNegative Joined Var(flag_whopr)
+Partitioned link-time optimization with number of parallel jobs or jobserver.
 
 ftree-builtin-call-dce
 Common Report Var(flag_tree_builtin_call_dce) Init(0) Optimization

gcc/doc/invoke.texi

@@ -7619,6 +7619,13 @@ parallel using @var{n} parallel jobs by utilizing an installed
 @command{make} program.  The environment variable @env{MAKE} may be
 used to override the program used.
 
+You can also specify @option{-fwhopr=jobserver} to use GNU make's 
+job server mode to determine the number of parallel jobs. This 
+is useful when the Makefile calling GCC is already parallel.
+The parent Makefile will need a @samp{+} prepended to the command recipe
+for this to work. This will likely only work if @env{MAKE} is 
+GNU make.
+
 Disabled by default.
 
 @item -fwpa

gcc/lto-wrapper.c

@@ -303,6 +303,7 @@ run_gcc (unsigned argc, char *argv[])
   struct obstack env_obstack;
   bool seen_o = false;
   int parallel = 0;
+  int jobserver = 0;
 
   /* Get the driver and options.  */
   collect_gcc = getenv ("COLLECT_GCC");
@@ -373,11 +374,19 @@ run_gcc (unsigned argc, char *argv[])
 	    lto_mode = LTO_MODE_WHOPR;
 	    if (option[7] == '=')
 	      {
+		if (!strcmp (option + 8, "jobserver"))
+		  {
+		    jobserver = 1;
+		    parallel = 1;
+		  }
+		else
+		  {
 		    parallel = atoi (option+8);
 		    if (parallel <= 1)
 		      parallel = 0;
 		  }
 	      }
+	  }
 	else
 	  *argv_ptr++ = option;
       }
@@ -567,23 +576,32 @@ cont:
 	{
 	  struct pex_obj *pex;
 	  char jobs[32];
+
 	  fprintf (mstream, "all:");
 	  for (i = 0; i < nr; ++i)
 	    fprintf (mstream, " \\\n\t%s", output_names[i]);
 	  fprintf (mstream, "\n");
 	  fclose (mstream);
-	  /* Avoid passing --jobserver-fd= and similar flags.  */
+	  if (!jobserver)
+	    {
+	      /* Avoid passing --jobserver-fd= and similar flags 
+		 unless jobserver mode is explicitly enabled.  */
 	      putenv (xstrdup ("MAKEFLAGS="));
 	      putenv (xstrdup ("MFLAGS="));
+	    }
 	  new_argv[0] = getenv ("MAKE");
 	  if (!new_argv[0])
 	    new_argv[0] = "make";
 	  new_argv[1] = "-f";
 	  new_argv[2] = makefile;
+	  i = 3;
+	  if (!jobserver)
+	    {
 	      snprintf (jobs, 31, "-j%d", parallel);
-	  new_argv[3] = jobs;
-	  new_argv[4] = "all";
-	  new_argv[5] = NULL;
+	      new_argv[i++] = jobs;
+	    }
+	  new_argv[i++] = "all";
+	  new_argv[i++] = NULL;
 	  pex = collect_execute (CONST_CAST (char **, new_argv));
 	  collect_wait (new_argv[0], pex);
 	  maybe_unlink_file (makefile);

gcc/opts.c

@@ -2089,7 +2089,7 @@ common_handle_option (const struct cl_decoded_option *decoded,
       break;
 
     case OPT_fwhopr:
-      flag_whopr = value;
+      flag_whopr = arg;
       break;
 
     case OPT_w: