gcc/lto-opts.c

   1 /* LTO IL options.
   2
   3    Copyright 2009, 2010, 2011, 2012 Free Software Foundation, Inc.
   4    Contributed by Simon Baldwin <simonb@google.com>
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "tree.h"
  26 #include "hashtab.h"
  27 #include "ggc.h"
  28 #include "vec.h"
  29 #include "bitmap.h"
  30 #include "flags.h"
  31 #include "opts.h"
  32 #include "options.h"
  33 #include "common/common-target.h"
  34 #include "diagnostic.h"
  35 #include "lto-streamer.h"
  36 #include "toplev.h"
  37
  38 /* Append the option piece OPT to the COLLECT_GCC_OPTIONS string
  39    set up by OB, appropriately quoted and separated by spaces
  40    (if !*FIRST_P).  */
  41
  42 static void
  43 append_to_collect_gcc_options (struct obstack *ob,
  44                                bool *first_p, const char *opt)
  45 {
  46   const char *p, *q = opt;
  47   if (!first_p)
  48     obstack_grow (ob, " ", 1);
  49   obstack_grow (ob, "'", 1);
  50   while ((p = strchr (q, '\'')))
  51     {
  52       obstack_grow (ob, q, p - q);
  53       obstack_grow (ob, "'\\''", 4);
  54       q = ++p;
  55     }
  56   obstack_grow (ob, q, strlen (q));
  57   obstack_grow (ob, "'", 1);
  58   *first_p = false;
  59 }
  60
  61 /* Write currently held options to an LTO IL section.  */
  62
  63 void
  64 lto_write_options (void)
  65 {
  66   struct lto_output_stream stream;
  67   char *section_name;
  68   struct obstack temporary_obstack;
  69   unsigned int i, j;
  70   char *args;
  71   bool first_p = true;
  72
  73   section_name = lto_get_section_name (LTO_section_opts, NULL, NULL);
  74   lto_begin_section (section_name, false);
  75   memset (&stream, 0, sizeof (stream));
  76
  77   obstack_init (&temporary_obstack);
  78
  79   /* Output options that affect GIMPLE IL semantics and are implicitely
  80      enabled by the frontend.
  81      This for now includes an explicit set of options that we also handle
  82      explicitly in lto-wrapper.c.  In the end the effects on GIMPLE IL
  83      semantics should be explicitely encoded in the IL or saved per
  84      function rather than per compilation unit.  */
  85   /* -fexceptions causes the EH machinery to be initialized, enabling
  86      generation of unwind data so that explicit throw() calls work.  */
  87   if (global_options.x_flag_exceptions)
  88     append_to_collect_gcc_options (&temporary_obstack, &first_p,
  89                                    "-fexceptions");
  90
  91   /* Output explicitely passed options.  */
  92   for (i = 1; i < save_decoded_options_count; ++i)
  93     {
  94       struct cl_decoded_option *option = &save_decoded_options[i];
  95
  96       /* Skip frontend and driver specific options here.  */
  97       if (!(cl_options[option->opt_index].flags & (CL_COMMON|CL_TARGET|CL_LTO)))
  98         continue;
  99
 100       /* Drop options created from the gcc driver that will be rejected
 101          when passed on to the driver again.  */
 102       if (cl_options[option->opt_index].cl_reject_driver)
 103         continue;
 104
 105       /* Also drop all options that are handled by the driver as well,
 106          which includes things like -o and -v or -fhelp for example.
 107          We do not need those.  Also drop all diagnostic options.  */
 108       if (cl_options[option->opt_index].flags & (CL_DRIVER|CL_WARNING))
 109         continue;
 110
 111       /* Skip explicitly some common options that we do not need.  */
 112       switch (option->opt_index)
 113         {
 114         case OPT_dumpbase:
 115         case OPT_SPECIAL_input_file:
 116           continue;
 117
 118         default:
 119           break;
 120         }
 121
 122       for (j = 0; j < option->canonical_option_num_elements; ++j)
 123         append_to_collect_gcc_options (&temporary_obstack, &first_p,
 124                                        option->canonical_option[j]);
 125     }
 126   obstack_grow (&temporary_obstack, "\0", 1);
 127   args = XOBFINISH (&temporary_obstack, char *);
 128   lto_output_data_stream (&stream, args, strlen (args) + 1);
 129
 130   lto_write_stream (&stream);
 131   lto_end_section ();
 132
 133   obstack_free (&temporary_obstack, NULL);
 134   free (section_name);
 135 }