gcc/lto-opts.c

   1 /* LTO IL options.
   2
   3    Copyright (C) 2009-2015 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 "hash-set.h"
  26 #include "machmode.h"
  27 #include "vec.h"
  28 #include "double-int.h"
  29 #include "input.h"
  30 #include "alias.h"
  31 #include "symtab.h"
  32 #include "options.h"
  33 #include "wide-int.h"
  34 #include "inchash.h"
  35 #include "tree.h"
  36 #include "fold-const.h"
  37 #include "predict.h"
  38 #include "tm.h"
  39 #include "hard-reg-set.h"
  40 #include "input.h"
  41 #include "function.h"
  42 #include "basic-block.h"
  43 #include "tree-ssa-alias.h"
  44 #include "internal-fn.h"
  45 #include "gimple-expr.h"
  46 #include "is-a.h"
  47 #include "gimple.h"
  48 #include "bitmap.h"
  49 #include "flags.h"
  50 #include "opts.h"
  51 #include "options.h"
  52 #include "common/common-target.h"
  53 #include "diagnostic.h"
  54 #include "hash-map.h"
  55 #include "plugin-api.h"
  56 #include "ipa-ref.h"
  57 #include "cgraph.h"
  58 #include "lto-streamer.h"
  59 #include "lto-section-names.h"
  60 #include "toplev.h"
  61
  62 /* Append the option piece OPT to the COLLECT_GCC_OPTIONS string
  63    set up by OB, appropriately quoted and separated by spaces
  64    (if !*FIRST_P).  */
  65
  66 static void
  67 append_to_collect_gcc_options (struct obstack *ob,
  68                                bool *first_p, const char *opt)
  69 {
  70   const char *p, *q = opt;
  71   if (!*first_p)
  72     obstack_grow (ob, " ", 1);
  73   obstack_grow (ob, "'", 1);
  74   while ((p = strchr (q, '\'')))
  75     {
  76       obstack_grow (ob, q, p - q);
  77       obstack_grow (ob, "'\\''", 4);
  78       q = ++p;
  79     }
  80   obstack_grow (ob, q, strlen (q));
  81   obstack_grow (ob, "'", 1);
  82   *first_p = false;
  83 }
  84
  85 /* Write currently held options to an LTO IL section.  */
  86
  87 void
  88 lto_write_options (void)
  89 {
  90   char *section_name;
  91   struct obstack temporary_obstack;
  92   unsigned int i, j;
  93   char *args;
  94   bool first_p = true;
  95
  96   section_name = lto_get_section_name (LTO_section_opts, NULL, NULL);
  97   lto_begin_section (section_name, false);
  98
  99   obstack_init (&temporary_obstack);
 100
 101   /* Output options that affect GIMPLE IL semantics and are implicitly
 102      enabled by the frontend.
 103      This for now includes an explicit set of options that we also handle
 104      explicitly in lto-wrapper.c.  In the end the effects on GIMPLE IL
 105      semantics should be explicitely encoded in the IL or saved per
 106      function rather than per compilation unit.  */
 107   /* -fexceptions causes the EH machinery to be initialized, enabling
 108      generation of unwind data so that explicit throw() calls work.  */
 109   if (!global_options_set.x_flag_exceptions
 110       && global_options.x_flag_exceptions)
 111     append_to_collect_gcc_options (&temporary_obstack, &first_p,
 112                                    "-fexceptions");
 113   /* -fnon-call-exceptions changes the generation of exception
 114       regions.  It is enabled implicitly by the Go frontend.  */
 115   if (!global_options_set.x_flag_non_call_exceptions
 116       && global_options.x_flag_non_call_exceptions)
 117     append_to_collect_gcc_options (&temporary_obstack, &first_p,
 118                                    "-fnon-call-exceptions");
 119   /* The default -ffp-contract changes depending on the language
 120      standard.  Pass thru conservative standard settings.  */
 121   if (!global_options_set.x_flag_fp_contract_mode)
 122     switch (global_options.x_flag_fp_contract_mode)
 123       {
 124       case FP_CONTRACT_OFF:
 125         append_to_collect_gcc_options (&temporary_obstack, &first_p,
 126                                        "-ffp-contract=off");
 127         break;
 128       case FP_CONTRACT_ON:
 129         append_to_collect_gcc_options (&temporary_obstack, &first_p,
 130                                        "-ffp-contract=on");
 131         break;
 132       case FP_CONTRACT_FAST:
 133         /* Nothing.  That merges conservatively and is the default for LTO.  */
 134         break;
 135       default:
 136         gcc_unreachable ();
 137       }
 138   /* The default -fmath-errno, -fsigned-zeros and -ftrapping-math change
 139      depending on the language (they can be disabled by the Ada and Java
 140      front-ends).  Pass thru conservative standard settings.  */
 141   if (!global_options_set.x_flag_errno_math)
 142     append_to_collect_gcc_options (&temporary_obstack, &first_p,
 143                                    global_options.x_flag_errno_math
 144                                    ? "-fmath-errno"
 145                                    : "-fno-math-errno");
 146   if (!global_options_set.x_flag_signed_zeros)
 147     append_to_collect_gcc_options (&temporary_obstack, &first_p,
 148                                    global_options.x_flag_signed_zeros
 149                                    ? "-fsigned-zeros"
 150                                    : "-fno-signed-zeros");
 151   if (!global_options_set.x_flag_trapping_math)
 152     append_to_collect_gcc_options (&temporary_obstack, &first_p,
 153                                    global_options.x_flag_trapping_math
 154                                    ? "-ftrapping-math"
 155                                    : "-fno-trapping-math");
 156   /* We need to merge -f[no-]strict-overflow, -f[no-]wrapv and -f[no-]trapv
 157      conservatively, so stream out their defaults.  */
 158   if (!global_options_set.x_flag_wrapv
 159       && global_options.x_flag_wrapv)
 160     append_to_collect_gcc_options (&temporary_obstack, &first_p, "-fwrapv");
 161   if (!global_options_set.x_flag_trapv
 162       && !global_options.x_flag_trapv)
 163     append_to_collect_gcc_options (&temporary_obstack, &first_p, "-fno-trapv");
 164   if (!global_options_set.x_flag_strict_overflow
 165       && !global_options.x_flag_strict_overflow)
 166     append_to_collect_gcc_options (&temporary_obstack, &first_p,
 167                                "-fno-strict-overflow");
 168
 169   /* Append options from target hook and store them to offload_lto section.  */
 170   if (lto_stream_offload_p)
 171     {
 172       char *offload_opts = targetm.offload_options ();
 173       char *offload_ptr = offload_opts;
 174       while (offload_ptr)
 175        {
 176          char *next = strchr (offload_ptr, ' ');
 177          if (next)
 178            *next++ = '\0';
 179          append_to_collect_gcc_options (&temporary_obstack, &first_p,
 180                                         offload_ptr);
 181          offload_ptr = next;
 182        }
 183       free (offload_opts);
 184     }
 185
 186   /* Output explicitly passed options.  */
 187   for (i = 1; i < save_decoded_options_count; ++i)
 188     {
 189       struct cl_decoded_option *option = &save_decoded_options[i];
 190
 191       /* Skip explicitly some common options that we do not need.  */
 192       switch (option->opt_index)
 193       {
 194         case OPT_dumpbase:
 195         case OPT_SPECIAL_unknown:
 196         case OPT_SPECIAL_ignore:
 197         case OPT_SPECIAL_program_name:
 198         case OPT_SPECIAL_input_file:
 199           continue;
 200
 201         default:
 202           break;
 203       }
 204
 205       /* Skip frontend and driver specific options here.  */
 206       if (!(cl_options[option->opt_index].flags & (CL_COMMON|CL_TARGET|CL_LTO)))
 207         continue;
 208
 209       /* Do not store target-specific options in offload_lto section.  */
 210       if ((cl_options[option->opt_index].flags & CL_TARGET)
 211           && lto_stream_offload_p)
 212        continue;
 213
 214       /* Drop options created from the gcc driver that will be rejected
 215          when passed on to the driver again.  */
 216       if (cl_options[option->opt_index].cl_reject_driver)
 217         continue;
 218
 219       /* Also drop all options that are handled by the driver as well,
 220          which includes things like -o and -v or -fhelp for example.
 221          We do not need those.  The only exception is -foffload option, if we
 222          write it in offload_lto section.  Also drop all diagnostic options.  */
 223       if ((cl_options[option->opt_index].flags & (CL_DRIVER|CL_WARNING))
 224           && (!lto_stream_offload_p || option->opt_index != OPT_foffload_))
 225         continue;
 226
 227       for (j = 0; j < option->canonical_option_num_elements; ++j)
 228         append_to_collect_gcc_options (&temporary_obstack, &first_p,
 229                                        option->canonical_option[j]);
 230     }
 231   obstack_grow (&temporary_obstack, "\0", 1);
 232   args = XOBFINISH (&temporary_obstack, char *);
 233   lto_write_data (args, strlen (args) + 1);
 234   lto_end_section ();
 235
 236   obstack_free (&temporary_obstack, NULL);
 237   free (section_name);
 238 }