libguile/inline.h

   1 /* classes: h_files */
   2
   3 #ifndef SCM_INLINE_H
   4 #define SCM_INLINE_H
   5
   6 /* Copyright (C) 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * This library 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 GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  21  */
  22
  23 /* This file is for inline functions.  On platforms that don't support
  24    inlining functions, they are turned into ordinary functions.  See
  25    "inline.c".
  26 */
  27
  28 #include "libguile/__scm.h"
  29
  30 #if (SCM_DEBUG_CELL_ACCESSES == 1)
  31 #include <stdio.h>
  32 #endif
  33
  34 #include "libguile/pairs.h"
  35 #include "libguile/gc.h"
  36 #include "libguile/threads.h"
  37 #include "libguile/unif.h"
  38
  39
  40 SCM_API SCM scm_cell (scm_t_bits car, scm_t_bits cdr);
  41 SCM_API SCM scm_double_cell (scm_t_bits car, scm_t_bits cbr,
  42                              scm_t_bits ccr, scm_t_bits cdr);
  43
  44 SCM_API SCM scm_array_handle_ref (scm_t_array_handle *h, ssize_t pos);
  45 SCM_API void scm_array_handle_set (scm_t_array_handle *h, ssize_t pos, SCM val);
  46
  47
  48 #if defined SCM_C_INLINE || defined SCM_INLINE_C_INCLUDING_INLINE_H
  49 /* either inlining, or being included from inline.c.  We use (and
  50    repeat) this long #if test here and below so that we don't have to
  51    introduce any extraneous symbols into the public namespace.  We
  52    only need SCM_C_INLINE to be seen publically . */
  53
  54 extern unsigned scm_newcell2_count;
  55 extern unsigned scm_newcell_count;
  56
  57 #if defined SCM_C_INLINE && ! defined SCM_INLINE_C_INCLUDING_INLINE_H
  58 /* definitely inlining */
  59 #ifdef __GNUC__
  60 extern
  61 #else
  62 static
  63 #endif
  64 SCM_C_INLINE
  65 #endif
  66 SCM
  67 scm_cell (scm_t_bits car, scm_t_bits cdr)
  68 {
  69   SCM z;
  70   SCM *freelist = SCM_FREELIST_LOC (scm_i_freelist);
  71
  72   if (scm_is_null (*freelist))
  73     z = scm_gc_for_newcell (&scm_i_master_freelist, freelist);
  74   else
  75     {
  76       z = *freelist;
  77       *freelist = SCM_FREE_CELL_CDR (*freelist);
  78     }
  79
  80   /*
  81     We update scm_cells_allocated from this function. If we don't
  82     update this explicitly, we will have to walk a freelist somewhere
  83     later on, which seems a lot more expensive.
  84    */
  85   scm_cells_allocated += 1;
  86
  87 #if (SCM_DEBUG_CELL_ACCESSES == 1)
  88     if (scm_debug_cell_accesses_p)
  89       {
  90         if (SCM_GC_MARK_P (z))
  91           {
  92             fprintf(stderr, "scm_cell tried to allocate a marked cell.\n");
  93             abort();
  94           }
  95         else if (SCM_GC_CELL_WORD(z, 0) != scm_tc_free_cell)
  96           {
  97             fprintf(stderr, "cell from freelist is not a free cell.\n");
  98             abort();
  99           }
 100       }
 101
 102     /*
 103       Always set mark. Otherwise cells that are alloced before
 104       scm_debug_cell_accesses_p is toggled seem invalid.
 105     */
 106     SCM_SET_GC_MARK (z);
 107
 108     /*
 109       TODO: figure out if this use of mark bits is valid with
 110       threading. What if another thread is doing GC at this point
 111       ... ?
 112      */
 113
 114 #endif
 115
 116
 117   /* Initialize the type slot last so that the cell is ignored by the
 118      GC until it is completely initialized.  This is only relevant
 119      when the GC can actually run during this code, which it can't
 120      since the GC only runs when all other threads are stopped.
 121   */
 122   SCM_GC_SET_CELL_WORD (z, 1, cdr);
 123   SCM_GC_SET_CELL_WORD (z, 0, car);
 124
 125 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 126   if (scm_expensive_debug_cell_accesses_p )
 127     scm_i_expensive_validation_check (z);
 128 #endif
 129
 130   return z;
 131 }
 132
 133 #if defined SCM_C_INLINE && ! defined SCM_INLINE_C_INCLUDING_INLINE_H
 134 /* definitely inlining */
 135 #ifdef __GNUC__
 136 extern
 137 #else
 138 static
 139 #endif
 140 SCM_C_INLINE
 141 #endif
 142 SCM
 143 scm_double_cell (scm_t_bits car, scm_t_bits cbr,
 144                  scm_t_bits ccr, scm_t_bits cdr)
 145 {
 146   SCM z;
 147   SCM *freelist = SCM_FREELIST_LOC (scm_i_freelist2);
 148
 149   if (scm_is_null (*freelist))
 150     z = scm_gc_for_newcell (&scm_i_master_freelist2, freelist);
 151   else
 152     {
 153       z = *freelist;
 154       *freelist = SCM_FREE_CELL_CDR (*freelist);
 155     }
 156
 157   scm_cells_allocated += 2;
 158
 159   /* Initialize the type slot last so that the cell is ignored by the
 160      GC until it is completely initialized.  This is only relevant
 161      when the GC can actually run during this code, which it can't
 162      since the GC only runs when all other threads are stopped.
 163   */
 164   SCM_GC_SET_CELL_WORD (z, 1, cbr);
 165   SCM_GC_SET_CELL_WORD (z, 2, ccr);
 166   SCM_GC_SET_CELL_WORD (z, 3, cdr);
 167   SCM_GC_SET_CELL_WORD (z, 0, car);
 168
 169 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 170   if (scm_debug_cell_accesses_p)
 171     {
 172       if (SCM_GC_MARK_P (z))
 173         {
 174           fprintf(stderr,
 175                   "scm_double_cell tried to allocate a marked cell.\n");
 176           abort();
 177         }
 178     }
 179
 180   /* see above. */
 181   SCM_SET_GC_MARK (z);
 182
 183 #endif
 184
 185   /* When this function is inlined, it's possible that the last
 186      SCM_GC_SET_CELL_WORD above will be adjacent to a following
 187      initialization of z.  E.g., it occurred in scm_make_real.  GCC
 188      from around version 3 (e.g., certainly 3.2) began taking
 189      advantage of strict C aliasing rules which say that it's OK to
 190      interchange the initialization above and the one below when the
 191      pointer types appear to differ sufficiently.  We don't want that,
 192      of course.  GCC allows this behaviour to be disabled with the
 193      -fno-strict-aliasing option, but would also need to be supplied
 194      by Guile users.  Instead, the following statements prevent the
 195      reordering.
 196    */
 197 #ifdef __GNUC__
 198   asm volatile ("" : : : "memory");
 199 #else
 200   /* portable version, just in case any other compiler does the same
 201      thing.  */
 202   scm_remember_upto_here_1 (z);
 203 #endif
 204
 205   return z;
 206 }
 207
 208 #if defined SCM_C_INLINE && ! defined SCM_INLINE_C_INCLUDING_INLINE_H
 209 /* definitely inlining */
 210 #ifdef __GNUC__
 211 extern
 212 #else
 213 static
 214 #endif
 215 SCM_C_INLINE
 216 #endif
 217 SCM
 218 scm_array_handle_ref (scm_t_array_handle *h, ssize_t p)
 219 {
 220   return h->ref (h, p);
 221 }
 222
 223 #if defined SCM_C_INLINE && ! defined SCM_INLINE_C_INCLUDING_INLINE_H
 224 /* definitely inlining */
 225 #ifdef __GNUC__
 226 extern
 227 #else
 228 static
 229 #endif
 230 SCM_C_INLINE
 231 #endif
 232 void
 233 scm_array_handle_set (scm_t_array_handle *h, ssize_t p, SCM v)
 234 {
 235   h->set (h, p, v);
 236 }
 237
 238 #endif
 239 #endif