gcc/cp/repo.c

   1 /* Code to maintain a C++ template repository.
   2    Copyright (C) 1995-2013 Free Software Foundation, Inc.
   3    Contributed by Jason Merrill (jason@cygnus.com)
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 3, or (at your option)
  10 any later version.
  11
  12 GCC is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 /* My strategy here is as follows:
  22
  23    Everything should be emitted in a translation unit where it is used.
  24    The results of the automatic process should be easily reproducible with
  25    explicit code.  */
  26
  27 #include "config.h"
  28 #include "system.h"
  29 #include "coretypes.h"
  30 #include "tm.h"
  31 #include "tree.h"
  32 #include "cp-tree.h"
  33 #include "input.h"
  34 #include "obstack.h"
  35 #include "toplev.h"
  36 #include "diagnostic-core.h"
  37 #include "flags.h"
  38
  39 static const char *extract_string (const char **);
  40 static const char *get_base_filename (const char *);
  41 static FILE *open_repo_file (const char *);
  42 static char *afgets (FILE *);
  43 static FILE *reopen_repo_file_for_write (void);
  44
  45 static GTY(()) vec<tree, va_gc> *pending_repo;
  46 static char *repo_name;
  47
  48 static const char *old_args, *old_dir, *old_main;
  49
  50 static struct obstack temporary_obstack;
  51 static bool temporary_obstack_initialized_p;
  52
  53 /* Parse a reasonable subset of shell quoting syntax.  */
  54
  55 static const char *
  56 extract_string (const char **pp)
  57 {
  58   const char *p = *pp;
  59   int backquote = 0;
  60   int inside = 0;
  61
  62   for (;;)
  63     {
  64       char c = *p;
  65       if (c == '\0')
  66         break;
  67       ++p;
  68       if (backquote)
  69         {
  70           obstack_1grow (&temporary_obstack, c);
  71           backquote = 0;
  72         }
  73       else if (! inside && c == ' ')
  74         break;
  75       else if (! inside && c == '\\')
  76         backquote = 1;
  77       else if (c == '\'')
  78         inside = !inside;
  79       else
  80         obstack_1grow (&temporary_obstack, c);
  81     }
  82
  83   obstack_1grow (&temporary_obstack, '\0');
  84   *pp = p;
  85   return (char *) obstack_finish (&temporary_obstack);
  86 }
  87
  88 static const char *
  89 get_base_filename (const char *filename)
  90 {
  91   const char *p = getenv ("COLLECT_GCC_OPTIONS");
  92   const char *output = NULL;
  93   int compiling = 0;
  94
  95   while (p && *p)
  96     {
  97       const char *q = extract_string (&p);
  98
  99       if (strcmp (q, "-o") == 0)
 100         {
 101           if (flag_compare_debug)
 102             /* Just in case aux_base_name was based on a name with two
 103                or more '.'s, add an arbitrary extension that will be
 104                stripped by the caller.  */
 105             output = concat (aux_base_name, ".o", NULL);
 106           else
 107             output = extract_string (&p);
 108         }
 109       else if (strcmp (q, "-c") == 0)
 110         compiling = 1;
 111     }
 112
 113   if (compiling && output)
 114     return output;
 115
 116   if (p && ! compiling)
 117     {
 118       warning (0, "-frepo must be used with -c");
 119       flag_use_repository = 0;
 120       return NULL;
 121     }
 122
 123   return lbasename (filename);
 124 }
 125
 126 static FILE *
 127 open_repo_file (const char *filename)
 128 {
 129   const char *p;
 130   const char *s = get_base_filename (filename);
 131
 132   if (s == NULL)
 133     return NULL;
 134
 135   p = lbasename (s);
 136   p = strrchr (p, '.');
 137   if (! p)
 138     p = s + strlen (s);
 139
 140   repo_name = XNEWVEC (char, p - s + 5);
 141   memcpy (repo_name, s, p - s);
 142   memcpy (repo_name + (p - s), ".rpo", 5);
 143
 144   return fopen (repo_name, "r");
 145 }
 146
 147 static char *
 148 afgets (FILE *stream)
 149 {
 150   int c;
 151   while ((c = getc (stream)) != EOF && c != '\n')
 152     obstack_1grow (&temporary_obstack, c);
 153   if (obstack_object_size (&temporary_obstack) == 0)
 154     return NULL;
 155   obstack_1grow (&temporary_obstack, '\0');
 156   return (char *) obstack_finish (&temporary_obstack);
 157 }
 158
 159 void
 160 init_repo (void)
 161 {
 162   char *buf;
 163   const char *p;
 164   FILE *repo_file;
 165
 166   if (! flag_use_repository)
 167     return;
 168
 169   /* When a PCH file is loaded, the entire identifier table is
 170      replaced, with the result that IDENTIFIER_REPO_CHOSEN is cleared.
 171      So, we have to reread the repository file.  */
 172   lang_post_pch_load = init_repo;
 173
 174   if (!temporary_obstack_initialized_p)
 175     gcc_obstack_init (&temporary_obstack);
 176
 177   repo_file = open_repo_file (main_input_filename);
 178
 179   if (repo_file == 0)
 180     return;
 181
 182   while ((buf = afgets (repo_file)))
 183     {
 184       switch (buf[0])
 185         {
 186         case 'A':
 187           old_args = ggc_strdup (buf + 2);
 188           break;
 189         case 'D':
 190           old_dir = ggc_strdup (buf + 2);
 191           break;
 192         case 'M':
 193           old_main = ggc_strdup (buf + 2);
 194           break;
 195         case 'O':
 196           /* A symbol that we were able to define the last time this
 197              file was compiled.  */
 198           break;
 199         case 'C':
 200           /* A symbol that the prelinker has requested that we
 201              define.  */
 202           {
 203             tree id = get_identifier (buf + 2);
 204             IDENTIFIER_REPO_CHOSEN (id) = 1;
 205           }
 206           break;
 207         default:
 208           error ("mysterious repository information in %s", repo_name);
 209         }
 210       obstack_free (&temporary_obstack, buf);
 211     }
 212   fclose (repo_file);
 213
 214   if (old_args && !get_random_seed (true)
 215       && (p = strstr (old_args, "'-frandom-seed=")))
 216     set_random_seed (extract_string (&p) + strlen ("-frandom-seed="));
 217 }
 218
 219 static FILE *
 220 reopen_repo_file_for_write (void)
 221 {
 222   FILE *repo_file = fopen (repo_name, "w");
 223
 224   if (repo_file == 0)
 225     {
 226       error ("can%'t create repository information file %qs", repo_name);
 227       flag_use_repository = 0;
 228     }
 229
 230   return repo_file;
 231 }
 232
 233 /* Emit any pending repos.  */
 234
 235 void
 236 finish_repo (void)
 237 {
 238   tree val;
 239   char *dir, *args;
 240   FILE *repo_file;
 241   unsigned ix;
 242
 243   if (!flag_use_repository || flag_compare_debug)
 244     return;
 245
 246   if (seen_error ())
 247     return;
 248
 249   repo_file = reopen_repo_file_for_write ();
 250   if (repo_file == 0)
 251     goto out;
 252
 253   fprintf (repo_file, "M %s\n", main_input_filename);
 254   dir = getpwd ();
 255   fprintf (repo_file, "D %s\n", dir);
 256   args = getenv ("COLLECT_GCC_OPTIONS");
 257   if (args)
 258     {
 259       fprintf (repo_file, "A %s", args);
 260       /* If -frandom-seed is not among the ARGS, then add the value
 261          that we chose.  That will ensure that the names of types from
 262          anonymous namespaces will get the same mangling when this
 263          file is recompiled.  */
 264       if (!strstr (args, "'-frandom-seed="))
 265         fprintf (repo_file, " '-frandom-seed=" HOST_WIDE_INT_PRINT_HEX_PURE "'",
 266                  get_random_seed (false));
 267       fprintf (repo_file, "\n");
 268     }
 269
 270   FOR_EACH_VEC_SAFE_ELT_REVERSE (pending_repo, ix, val)
 271     {
 272       tree name = DECL_ASSEMBLER_NAME (val);
 273       char type = IDENTIFIER_REPO_CHOSEN (name) ? 'C' : 'O';
 274       fprintf (repo_file, "%c %s\n", type, IDENTIFIER_POINTER (name));
 275     }
 276
 277  out:
 278   if (repo_file)
 279     fclose (repo_file);
 280 }
 281
 282 /* DECL is a FUNCTION_DECL or VAR_DECL with vague linkage whose
 283    definition is available in this translation unit.  Returns 0 if
 284    this definition should not be emitted in this translation unit
 285    because it will be emitted elsewhere.  Returns 1 if the repository
 286    file indicates that that DECL should be emitted in this translation
 287    unit, or 2 if the repository file is not in use.  */
 288
 289 int
 290 repo_emit_p (tree decl)
 291 {
 292   int ret = 0;
 293   gcc_assert (TREE_PUBLIC (decl));
 294   gcc_assert (VAR_OR_FUNCTION_DECL_P (decl));
 295   gcc_assert (!DECL_REALLY_EXTERN (decl));
 296
 297   /* When not using the repository, emit everything.  */
 298   if (!flag_use_repository)
 299     return 2;
 300
 301   /* Only template instantiations are managed by the repository.  This
 302      is an artificial restriction; the code in the prelinker and here
 303      will work fine if all entities with vague linkage are managed by
 304      the repository.  */
 305   if (VAR_P (decl))
 306     {
 307       tree type = NULL_TREE;
 308       if (DECL_VTABLE_OR_VTT_P (decl))
 309         type = DECL_CONTEXT (decl);
 310       else if (DECL_TINFO_P (decl))
 311         type = TREE_TYPE (DECL_NAME (decl));
 312       if (!DECL_TEMPLATE_INSTANTIATION (decl)
 313           && (!TYPE_LANG_SPECIFIC (type)
 314               || !CLASSTYPE_TEMPLATE_INSTANTIATION (type)))
 315         return 2;
 316       /* Const static data members initialized by constant expressions must
 317          be processed where needed so that their definitions are
 318          available.  Still record them into *.rpo files, so if they
 319          weren't actually emitted and collect2 requests them, they can
 320          be provided.  */
 321       if (decl_maybe_constant_var_p (decl)
 322           && DECL_CLASS_SCOPE_P (decl))
 323         ret = 2;
 324     }
 325   else if (!DECL_TEMPLATE_INSTANTIATION (decl))
 326     return 2;
 327
 328   if (DECL_EXPLICIT_INSTANTIATION (decl))
 329     return 2;
 330
 331   /* For constructors and destructors, the repository contains
 332      information about the clones -- not the original function --
 333      because only the clones are emitted in the object file.  */
 334   if (DECL_MAYBE_IN_CHARGE_CONSTRUCTOR_P (decl)
 335       || DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (decl))
 336     {
 337       int emit_p = 0;
 338       tree clone;
 339       /* There is no early exit from this loop because we want to
 340          ensure that all of the clones are marked as available in this
 341          object file.  */
 342       FOR_EACH_CLONE (clone, decl)
 343         /* The only possible results from the recursive call to
 344            repo_emit_p are 0 or 1.  */
 345         if (repo_emit_p (clone))
 346           emit_p = 1;
 347       return emit_p;
 348     }
 349
 350   /* Keep track of all available entities.  */
 351   if (!DECL_REPO_AVAILABLE_P (decl))
 352     {
 353       DECL_REPO_AVAILABLE_P (decl) = 1;
 354       vec_safe_push (pending_repo, decl);
 355     }
 356
 357   return IDENTIFIER_REPO_CHOSEN (DECL_ASSEMBLER_NAME (decl)) ? 1 : ret;
 358 }
 359
 360 /* Returns true iff the prelinker has explicitly marked CLASS_TYPE for
 361    export from this translation unit.  */
 362
 363 bool
 364 repo_export_class_p (const_tree class_type)
 365 {
 366   if (!flag_use_repository)
 367     return false;
 368   if (!CLASSTYPE_VTABLES (class_type))
 369     return false;
 370   /* If the virtual table has been assigned to this translation unit,
 371      export the class.  */
 372   return (IDENTIFIER_REPO_CHOSEN
 373           (DECL_ASSEMBLER_NAME (CLASSTYPE_VTABLES (class_type))));
 374 }
 375
 376 #include "gt-cp-repo.h"