gcc/cp/repo.c

   1 /* Code to maintain a C++ template repository.
   2    Copyright (C) 1995, 1996, 1997, 1998, 2000, 2001, 2002, 2003, 2004, 2005
   3    Free Software Foundation, Inc.
   4    Contributed by Jason Merrill (jason@cygnus.com)
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 2, or (at your option)
  11 any later version.
  12
  13 GCC is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING.  If not, write to
  20 the Free Software Foundation, 51 Franklin Street, Fifth Floor,
  21 Boston, MA 02110-1301, USA.  */
  22
  23 /* My strategy here is as follows:
  24
  25    Everything should be emitted in a translation unit where it is used.
  26    The results of the automatic process should be easily reproducible with
  27    explicit code.  */
  28
  29 #include "config.h"
  30 #include "system.h"
  31 #include "coretypes.h"
  32 #include "tm.h"
  33 #include "tree.h"
  34 #include "cp-tree.h"
  35 #include "input.h"
  36 #include "obstack.h"
  37 #include "toplev.h"
  38 #include "diagnostic.h"
  39 #include "flags.h"
  40
  41 static char *extract_string (char **);
  42 static const char *get_base_filename (const char *);
  43 static FILE *open_repo_file (const char *);
  44 static char *afgets (FILE *);
  45 static FILE *reopen_repo_file_for_write (void);
  46
  47 static GTY(()) tree pending_repo;
  48 static char *repo_name;
  49
  50 static const char *old_args, *old_dir, *old_main;
  51
  52 static struct obstack temporary_obstack;
  53 static bool temporary_obstack_initialized_p;
  54
  55 /* Parse a reasonable subset of shell quoting syntax.  */
  56
  57 static char *
  58 extract_string (char **pp)
  59 {
  60   char *p = *pp;
  61   int backquote = 0;
  62   int inside = 0;
  63
  64   for (;;)
  65     {
  66       char c = *p;
  67       if (c == '\0')
  68         break;
  69       ++p;
  70       if (backquote)
  71         {
  72           obstack_1grow (&temporary_obstack, c);
  73           backquote = 0;
  74         }
  75       else if (! inside && c == ' ')
  76         break;
  77       else if (! inside && c == '\\')
  78         backquote = 1;
  79       else if (c == '\'')
  80         inside = !inside;
  81       else
  82         obstack_1grow (&temporary_obstack, c);
  83     }
  84
  85   obstack_1grow (&temporary_obstack, '\0');
  86   *pp = p;
  87   return (char *) obstack_finish (&temporary_obstack);
  88 }
  89
  90 static const char *
  91 get_base_filename (const char *filename)
  92 {
  93   char *p = getenv ("COLLECT_GCC_OPTIONS");
  94   char *output = NULL;
  95   int compiling = 0;
  96
  97   while (p && *p)
  98     {
  99       char *q = extract_string (&p);
 100
 101       if (strcmp (q, "-o") == 0)
 102         output = extract_string (&p);
 103       else if (strcmp (q, "-c") == 0)
 104         compiling = 1;
 105     }
 106
 107   if (compiling && output)
 108     return output;
 109
 110   if (p && ! compiling)
 111     {
 112       warning (0, "-frepo must be used with -c");
 113       flag_use_repository = 0;
 114       return NULL;
 115     }
 116
 117   return lbasename (filename);
 118 }
 119
 120 static FILE *
 121 open_repo_file (const char *filename)
 122 {
 123   const char *p;
 124   const char *s = get_base_filename (filename);
 125
 126   if (s == NULL)
 127     return NULL;
 128
 129   p = lbasename (s);
 130   p = strrchr (p, '.');
 131   if (! p)
 132     p = s + strlen (s);
 133
 134   repo_name = XNEWVEC (char, p - s + 5);
 135   memcpy (repo_name, s, p - s);
 136   memcpy (repo_name + (p - s), ".rpo", 5);
 137
 138   return fopen (repo_name, "r");
 139 }
 140
 141 static char *
 142 afgets (FILE *stream)
 143 {
 144   int c;
 145   while ((c = getc (stream)) != EOF && c != '\n')
 146     obstack_1grow (&temporary_obstack, c);
 147   if (obstack_object_size (&temporary_obstack) == 0)
 148     return NULL;
 149   obstack_1grow (&temporary_obstack, '\0');
 150   return (char *) obstack_finish (&temporary_obstack);
 151 }
 152
 153 void
 154 init_repo (void)
 155 {
 156   char *buf;
 157   FILE *repo_file;
 158
 159   if (! flag_use_repository)
 160     return;
 161
 162   /* When a PCH file is loaded, the entire identifier table is
 163      replaced, with the result that IDENTIFIER_REPO_CHOSEN is cleared.
 164      So, we have to reread the repository file.  */
 165   lang_post_pch_load = init_repo;
 166
 167   if (!temporary_obstack_initialized_p)
 168     gcc_obstack_init (&temporary_obstack);
 169
 170   repo_file = open_repo_file (main_input_filename);
 171
 172   if (repo_file == 0)
 173     return;
 174
 175   while ((buf = afgets (repo_file)))
 176     {
 177       switch (buf[0])
 178         {
 179         case 'A':
 180           old_args = ggc_strdup (buf + 2);
 181           break;
 182         case 'D':
 183           old_dir = ggc_strdup (buf + 2);
 184           break;
 185         case 'M':
 186           old_main = ggc_strdup (buf + 2);
 187           break;
 188         case 'O':
 189           /* A symbol that we were able to define the last time this
 190              file was compiled.  */
 191           break;
 192         case 'C':
 193           /* A symbol that the prelinker has requested that we
 194              define.  */
 195           {
 196             tree id = get_identifier (buf + 2);
 197             IDENTIFIER_REPO_CHOSEN (id) = 1;
 198           }
 199           break;
 200         default:
 201           error ("mysterious repository information in %s", repo_name);
 202         }
 203       obstack_free (&temporary_obstack, buf);
 204     }
 205   fclose (repo_file);
 206 }
 207
 208 static FILE *
 209 reopen_repo_file_for_write (void)
 210 {
 211   FILE *repo_file = fopen (repo_name, "w");
 212
 213   if (repo_file == 0)
 214     {
 215       error ("can't create repository information file %qs", repo_name);
 216       flag_use_repository = 0;
 217     }
 218
 219   return repo_file;
 220 }
 221
 222 /* Emit any pending repos.  */
 223
 224 void
 225 finish_repo (void)
 226 {
 227   tree t;
 228   char *dir, *args;
 229   FILE *repo_file;
 230
 231   if (!flag_use_repository)
 232     return;
 233
 234   if (errorcount || sorrycount)
 235     return;
 236
 237   repo_file = reopen_repo_file_for_write ();
 238   if (repo_file == 0)
 239     goto out;
 240
 241   fprintf (repo_file, "M %s\n", main_input_filename);
 242   dir = getpwd ();
 243   fprintf (repo_file, "D %s\n", dir);
 244   args = getenv ("COLLECT_GCC_OPTIONS");
 245   if (args)
 246     {
 247       fprintf (repo_file, "A %s", args);
 248       /* If -frandom-seed is not among the ARGS, then add the value
 249          that we chose.  That will ensure that the names of types from
 250          anonymous namespaces will get the same mangling when this
 251          file is recompiled.  */
 252       if (!strstr (args, "'-frandom-seed="))
 253         fprintf (repo_file, " '-frandom-seed=%s'", flag_random_seed);
 254       fprintf (repo_file, "\n");
 255     }
 256
 257   for (t = pending_repo; t; t = TREE_CHAIN (t))
 258     {
 259       tree val = TREE_VALUE (t);
 260       tree name = DECL_ASSEMBLER_NAME (val);
 261       char type = IDENTIFIER_REPO_CHOSEN (name) ? 'C' : 'O';
 262       fprintf (repo_file, "%c %s\n", type, IDENTIFIER_POINTER (name));
 263     }
 264
 265  out:
 266   if (repo_file)
 267     fclose (repo_file);
 268 }
 269
 270 /* DECL is a FUNCTION_DECL or VAR_DECL with vague linkage whose
 271    definition is available in this translation unit.  Returns 0 if
 272    this definition should not be emitted in this translation unit
 273    because it will be emitted elsewhere.  Returns 1 if the repository
 274    file indicates that that DECL should be emitted in this translation
 275    unit, or 2 if the repository file is not in use.  */
 276
 277 int
 278 repo_emit_p (tree decl)
 279 {
 280   gcc_assert (TREE_PUBLIC (decl));
 281   gcc_assert (TREE_CODE (decl) == FUNCTION_DECL
 282               || TREE_CODE (decl) == VAR_DECL);
 283   gcc_assert (!DECL_REALLY_EXTERN (decl));
 284
 285   /* When not using the repository, emit everything.  */
 286   if (!flag_use_repository)
 287     return 2;
 288
 289   /* Only template instantiations are managed by the repository.  This
 290      is an artificial restriction; the code in the prelinker and here
 291      will work fine if all entities with vague linkage are managed by
 292      the repository.  */
 293   if (TREE_CODE (decl) == VAR_DECL)
 294     {
 295       tree type = NULL_TREE;
 296       if (DECL_VTABLE_OR_VTT_P (decl))
 297         type = DECL_CONTEXT (decl);
 298       else if (DECL_TINFO_P (decl))
 299         type = TREE_TYPE (DECL_NAME (decl));
 300       if (!DECL_TEMPLATE_INSTANTIATION (decl)
 301           && (!TYPE_LANG_SPECIFIC (type)
 302               || !CLASSTYPE_TEMPLATE_INSTANTIATION (type)))
 303         return 2;
 304       /* Static data members initialized by constant expressions must
 305          be processed where needed so that their definitions are
 306          available.  */
 307       if (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (decl)
 308           && DECL_CLASS_SCOPE_P (decl))
 309         return 2;
 310     }
 311   else if (!DECL_TEMPLATE_INSTANTIATION (decl))
 312     return 2;
 313
 314   /* For constructors and destructors, the repository contains
 315      information about the clones -- not the original function --
 316      because only the clones are emitted in the object file.  */
 317   if (DECL_MAYBE_IN_CHARGE_CONSTRUCTOR_P (decl)
 318       || DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (decl))
 319     {
 320       int emit_p = 0;
 321       tree clone;
 322       /* There is no early exit from this loop because we want to
 323          ensure that all of the clones are marked as available in this
 324          object file.  */
 325       FOR_EACH_CLONE (clone, decl)
 326         /* The only possible results from the recursive call to
 327            repo_emit_p are 0 or 1.  */
 328         if (repo_emit_p (clone))
 329           emit_p = 1;
 330       return emit_p;
 331     }
 332
 333   /* Keep track of all available entities.  */
 334   if (!DECL_REPO_AVAILABLE_P (decl))
 335     {
 336       DECL_REPO_AVAILABLE_P (decl) = 1;
 337       pending_repo = tree_cons (NULL_TREE, decl, pending_repo);
 338     }
 339
 340   return IDENTIFIER_REPO_CHOSEN (DECL_ASSEMBLER_NAME (decl));
 341 }
 342
 343 /* Returns true iff the prelinker has explicitly marked CLASS_TYPE for
 344    export from this translation unit.  */
 345
 346 bool
 347 repo_export_class_p (tree class_type)
 348 {
 349   if (!flag_use_repository)
 350     return false;
 351   if (!CLASSTYPE_VTABLES (class_type))
 352     return false;
 353   /* If the virtual table has been assigned to this translation unit,
 354      export the class.  */
 355   return (IDENTIFIER_REPO_CHOSEN
 356           (DECL_ASSEMBLER_NAME (CLASSTYPE_VTABLES (class_type))));
 357 }
 358
 359 #include "gt-cp-repo.h"