gcc/lto-opts.c

   1 /* LTO IL options.
   2
   3    Copyright (C) 2009-2013 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 explicitly some common options that we do not need.  */
  97       switch (option->opt_index)
  98       {
  99         case OPT_dumpbase:
 100         case OPT_SPECIAL_unknown:
 101         case OPT_SPECIAL_ignore:
 102         case OPT_SPECIAL_program_name:
 103         case OPT_SPECIAL_input_file:
 104           continue;
 105
 106         default:
 107           break;
 108       }
 109
 110       /* Skip frontend and driver specific options here.  */
 111       if (!(cl_options[option->opt_index].flags & (CL_COMMON|CL_TARGET|CL_LTO)))
 112         continue;
 113
 114       /* Drop options created from the gcc driver that will be rejected
 115          when passed on to the driver again.  */
 116       if (cl_options[option->opt_index].cl_reject_driver)
 117         continue;
 118
 119       /* Also drop all options that are handled by the driver as well,
 120          which includes things like -o and -v or -fhelp for example.
 121          We do not need those.  Also drop all diagnostic options.  */
 122       if (cl_options[option->opt_index].flags & (CL_DRIVER|CL_WARNING))
 123         continue;
 124
 125       for (j = 0; j < option->canonical_option_num_elements; ++j)
 126         append_to_collect_gcc_options (&temporary_obstack, &first_p,
 127                                        option->canonical_option[j]);
 128     }
 129   obstack_grow (&temporary_obstack, "\0", 1);
 130   args = XOBFINISH (&temporary_obstack, char *);
 131   lto_output_data_stream (&stream, args, strlen (args) + 1);
 132
 133   lto_write_stream (&stream);
 134   lto_end_section ();
 135
 136   obstack_free (&temporary_obstack, NULL);
 137   free (section_name);
 138 }