src/puresize.h

   1 /* How much read-only Lisp storage a dumped Emacs needs.
   2    Copyright (C) 1993, 2001-2012  Free Software Foundation, Inc.
   3
   4 This file is part of GNU Emacs.
   5
   6 GNU Emacs is free software: you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation, either version 3 of the License, or
   9 (at your option) any later version.
  10
  11 GNU Emacs is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
  18
  19 /* Define PURESIZE, the number of bytes of pure Lisp code to leave space for.
  20
  21    At one point, this was defined in config.h, meaning that changing
  22    PURESIZE would make Make recompile all of Emacs.  But only a few
  23    files actually use PURESIZE, so we split it out to its own .h file.
  24
  25    Make sure to include this file after config.h, since that tells us
  26    whether we are running X windows, which tells us how much pure
  27    storage to allocate.  */
  28
  29 /* First define a measure of the amount of data we have.  */
  30
  31 /* A system configuration file may set this to request a certain extra
  32    amount of storage.  This is a lot more update-robust that defining
  33    BASE_PURESIZE or even PURESIZE directly.  */
  34 #ifndef SYSTEM_PURESIZE_EXTRA
  35 #define SYSTEM_PURESIZE_EXTRA 0
  36 #endif
  37
  38 #ifndef SITELOAD_PURESIZE_EXTRA
  39 #define SITELOAD_PURESIZE_EXTRA 0
  40 #endif
  41
  42 #ifndef BASE_PURESIZE
  43 #define BASE_PURESIZE (1620000 + SYSTEM_PURESIZE_EXTRA + SITELOAD_PURESIZE_EXTRA)
  44 #endif
  45
  46 /* Increase BASE_PURESIZE by a ratio depending on the machine's word size.  */
  47 #ifndef PURESIZE_RATIO
  48 #if EMACS_INT_MAX >> 31 != 0
  49 #if PTRDIFF_MAX >> 31 != 0
  50 #define PURESIZE_RATIO 10 / 6   /* Don't surround with `()'.  */
  51 #else
  52 #define PURESIZE_RATIO 8 / 6    /* Don't surround with `()'.  */
  53 #endif
  54 #else
  55 #define PURESIZE_RATIO 1
  56 #endif
  57 #endif
  58
  59 #ifdef ENABLE_CHECKING
  60 /* ENABLE_CHECKING somehow increases the purespace used, probably because
  61    it tends to cause some macro arguments to be evaluated twice.  This is
  62    a bug, but it's difficult to track it down.  */
  63 #define PURESIZE_CHECKING_RATIO 12 / 10 /* Don't surround with `()'.  */
  64 #else
  65 #define PURESIZE_CHECKING_RATIO 1
  66 #endif
  67
  68 /* This is the actual size in bytes to allocate.  */
  69 #ifndef PURESIZE
  70 #define PURESIZE  (BASE_PURESIZE * PURESIZE_RATIO * PURESIZE_CHECKING_RATIO)
  71 #endif
  72
  73 /* Signal an error if OBJ is pure.  */
  74 #define CHECK_IMPURE(obj) \
  75   { if (PURE_P (obj))     \
  76       pure_write_error (); }
  77
  78 extern _Noreturn void pure_write_error (void);
  79 \f
  80 /* Define PURE_P.  */
  81
  82 extern EMACS_INT pure[];
  83
  84 #define PURE_P(obj) \
  85   ((uintptr_t) XPNTR (obj) - (uintptr_t) pure <= PURESIZE)