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, 2006, 2008, 2009 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 License
  10  * as published by the Free Software Foundation; either version 3 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful, but
  14  * 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., 51 Franklin Street, Fifth Floor, Boston, MA
  21  * 02110-1301 USA
  22  */
  23
  24 /* This file is for inline functions.  On platforms that don't support
  25    inlining functions, they are turned into ordinary functions.  See
  26    "inline.c".
  27 */
  28
  29 #include <stdio.h>
  30 #include <string.h>
  31
  32 #include "libguile/__scm.h"
  33
  34 #include "libguile/pairs.h"
  35 #include "libguile/gc.h"
  36 #include "libguile/threads.h"
  37 #include "libguile/array-handle.h"
  38 #include "libguile/ports.h"
  39 #include "libguile/numbers.h"
  40 #include "libguile/error.h"
  41
  42
  43 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
  44
  45 /* GCC has `__inline__' in all modes, including strict ansi.  GCC 4.3 and
  46    above with `-std=c99' or `-std=gnu99' implements ISO C99 inline semantics,
  47    unless `-fgnu89-inline' is used.  Here we want GNU "extern inline"
  48    semantics, hence the `__gnu_inline__' attribute, in accordance with:
  49    http://gcc.gnu.org/gcc-4.3/porting_to.html .
  50
  51    With GCC 4.2, `__GNUC_STDC_INLINE__' is never defined (because C99 inline
  52    semantics are not supported), but a warning is issued in C99 mode if
  53    `__gnu_inline__' is not used.
  54
  55    Apple's GCC build >5400 (since Xcode 3.0) doesn't support GNU inline in
  56    C99 mode and doesn't define `__GNUC_STDC_INLINE__'.  Fall back to "static
  57    inline" in that case.  */
  58
  59 # if (defined __GNUC__) && (!(((defined __APPLE_CC__) && (__APPLE_CC__ > 5400)) && __STDC_VERSION__ >= 199901L))
  60 #  define SCM_C_USE_EXTERN_INLINE 1
  61 #  if (defined __GNUC_STDC_INLINE__) || (__GNUC__ == 4 && __GNUC_MINOR__ == 2)
  62 #   define SCM_C_EXTERN_INLINE                                  \
  63            extern __inline__ __attribute__ ((__gnu_inline__))
  64 #  else
  65 #   define SCM_C_EXTERN_INLINE extern __inline__
  66 #  endif
  67 # elif (defined SCM_C_INLINE)
  68 #  define SCM_C_EXTERN_INLINE static SCM_C_INLINE
  69 # endif
  70
  71 #endif /* SCM_INLINE_C_INCLUDING_INLINE_H */
  72
  73
  74 #if (!defined SCM_C_INLINE) || (defined SCM_INLINE_C_INCLUDING_INLINE_H) \
  75     || (defined SCM_C_USE_EXTERN_INLINE)
  76
  77 /* The `extern' declarations.  They should only appear when used from
  78    "inline.c", when `inline' is not supported at all or when "extern inline"
  79    is used.  */
  80
  81 SCM_API SCM scm_cell (scm_t_bits car, scm_t_bits cdr);
  82 SCM_API SCM scm_double_cell (scm_t_bits car, scm_t_bits cbr,
  83                              scm_t_bits ccr, scm_t_bits cdr);
  84
  85 SCM_API SCM scm_array_handle_ref (scm_t_array_handle *h, ssize_t pos);
  86 SCM_API void scm_array_handle_set (scm_t_array_handle *h, ssize_t pos, SCM val);
  87
  88 SCM_API int scm_is_pair (SCM x);
  89
  90 SCM_API int scm_get_byte_or_eof (SCM port);
  91 SCM_API void scm_putc (char c, SCM port);
  92 SCM_API void scm_puts (const char *str_data, SCM port);
  93
  94 #endif
  95
  96
  97 #if defined SCM_C_EXTERN_INLINE || defined SCM_INLINE_C_INCLUDING_INLINE_H
  98 /* either inlining, or being included from inline.c.  We use (and
  99    repeat) this long #if test here and below so that we don't have to
 100    introduce any extraneous symbols into the public namespace.  We
 101    only need SCM_C_INLINE to be seen publically . */
 102
 103 extern unsigned scm_newcell2_count;
 104 extern unsigned scm_newcell_count;
 105
 106
 107 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
 108 SCM_C_EXTERN_INLINE
 109 #endif
 110 SCM
 111 scm_cell (scm_t_bits car, scm_t_bits cdr)
 112 {
 113   SCM z;
 114   SCM *freelist = SCM_FREELIST_LOC (scm_i_freelist);
 115
 116   if (scm_is_null (*freelist))
 117     z = scm_gc_for_newcell (&scm_i_master_freelist, freelist);
 118   else
 119     {
 120       z = *freelist;
 121       *freelist = SCM_FREE_CELL_CDR (*freelist);
 122     }
 123
 124 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 125     if (scm_debug_cell_accesses_p)
 126       {
 127         if (SCM_GC_MARK_P (z))
 128           {
 129             fprintf(stderr, "scm_cell tried to allocate a marked cell.\n");
 130             abort();
 131           }
 132         else if (SCM_GC_CELL_WORD(z, 0) != scm_tc_free_cell)
 133           {
 134             fprintf(stderr, "cell from freelist is not a free cell.\n");
 135             abort();
 136           }
 137       }
 138
 139 #if (SCM_DEBUG_MARKING_API == 0)
 140     /*
 141       Always set mark. Otherwise cells that are alloced before
 142       scm_debug_cell_accesses_p is toggled seem invalid.
 143     */
 144     SCM_SET_GC_MARK (z);
 145 #endif /* SCM_DEBUG_MARKING_API */
 146
 147     /*
 148       TODO: figure out if this use of mark bits is valid with
 149       threading. What if another thread is doing GC at this point
 150       ... ?
 151      */
 152 #endif
 153
 154
 155   /* Initialize the type slot last so that the cell is ignored by the
 156      GC until it is completely initialized.  This is only relevant
 157      when the GC can actually run during this code, which it can't
 158      since the GC only runs when all other threads are stopped.
 159   */
 160   SCM_GC_SET_CELL_WORD (z, 1, cdr);
 161   SCM_GC_SET_CELL_WORD (z, 0, car);
 162
 163 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 164   if (scm_expensive_debug_cell_accesses_p )
 165     scm_i_expensive_validation_check (z);
 166 #endif
 167
 168   return z;
 169 }
 170
 171 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
 172 SCM_C_EXTERN_INLINE
 173 #endif
 174 SCM
 175 scm_double_cell (scm_t_bits car, scm_t_bits cbr,
 176                  scm_t_bits ccr, scm_t_bits cdr)
 177 {
 178   SCM z;
 179   SCM *freelist = SCM_FREELIST_LOC (scm_i_freelist2);
 180
 181   if (scm_is_null (*freelist))
 182     z = scm_gc_for_newcell (&scm_i_master_freelist2, freelist);
 183   else
 184     {
 185       z = *freelist;
 186       *freelist = SCM_FREE_CELL_CDR (*freelist);
 187     }
 188
 189   /* Initialize the type slot last so that the cell is ignored by the
 190      GC until it is completely initialized.  This is only relevant
 191      when the GC can actually run during this code, which it can't
 192      since the GC only runs when all other threads are stopped.
 193   */
 194   SCM_GC_SET_CELL_WORD (z, 1, cbr);
 195   SCM_GC_SET_CELL_WORD (z, 2, ccr);
 196   SCM_GC_SET_CELL_WORD (z, 3, cdr);
 197   SCM_GC_SET_CELL_WORD (z, 0, car);
 198
 199 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 200   if (scm_debug_cell_accesses_p)
 201     {
 202       if (SCM_GC_MARK_P (z))
 203         {
 204           fprintf(stderr,
 205                   "scm_double_cell tried to allocate a marked cell.\n");
 206           abort();
 207         }
 208     }
 209 #if (SCM_DEBUG_MARKING_API == 0)
 210   /* see above. */
 211   SCM_SET_GC_MARK (z);
 212 #endif /* SCM_DEBUG_MARKING_API */
 213
 214 #endif
 215
 216   /* When this function is inlined, it's possible that the last
 217      SCM_GC_SET_CELL_WORD above will be adjacent to a following
 218      initialization of z.  E.g., it occurred in scm_make_real.  GCC
 219      from around version 3 (e.g., certainly 3.2) began taking
 220      advantage of strict C aliasing rules which say that it's OK to
 221      interchange the initialization above and the one below when the
 222      pointer types appear to differ sufficiently.  We don't want that,
 223      of course.  GCC allows this behaviour to be disabled with the
 224      -fno-strict-aliasing option, but would also need to be supplied
 225      by Guile users.  Instead, the following statements prevent the
 226      reordering.
 227    */
 228 #ifdef __GNUC__
 229   __asm__ volatile ("" : : : "memory");
 230 #else
 231   /* portable version, just in case any other compiler does the same
 232      thing.  */
 233   scm_remember_upto_here_1 (z);
 234 #endif
 235
 236   return z;
 237 }
 238
 239 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
 240 SCM_C_EXTERN_INLINE
 241 #endif
 242 SCM
 243 scm_array_handle_ref (scm_t_array_handle *h, ssize_t p)
 244 {
 245   if (SCM_UNLIKELY (p < 0 && -p > h->base))
 246     /* catch overflow */
 247     scm_out_of_range (NULL, scm_from_ssize_t (p));
 248   /* perhaps should catch overflow here too */
 249   return h->impl->vref (h, h->base + p);
 250 }
 251
 252 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
 253 SCM_C_EXTERN_INLINE
 254 #endif
 255 void
 256 scm_array_handle_set (scm_t_array_handle *h, ssize_t p, SCM v)
 257 {
 258   if (SCM_UNLIKELY (p < 0 && -p > h->base))
 259     /* catch overflow */
 260     scm_out_of_range (NULL, scm_from_ssize_t (p));
 261   /* perhaps should catch overflow here too */
 262   h->impl->vset (h, h->base + p, v);
 263 }
 264
 265 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
 266 SCM_C_EXTERN_INLINE
 267 #endif
 268 int
 269 scm_is_pair (SCM x)
 270 {
 271   /* The following "workaround_for_gcc_295" avoids bad code generated by
 272      i386 gcc 2.95.4 (the Debian packaged 2.95.4-24 at least).
 273
 274      Under the default -O2 the inlined SCM_I_CONSP test gets "optimized" so
 275      the fetch of the tag word from x is done before confirming it's a
 276      non-immediate (SCM_NIMP).  Needless to say that bombs badly if x is a
 277      immediate.  This was seen to afflict scm_srfi1_split_at and something
 278      deep in the bowels of ceval().  In both cases segvs resulted from
 279      deferencing a random immediate value.  srfi-1.test exposes the problem
 280      through a short list, the immediate being SCM_EOL in that case.
 281      Something in syntax.test exposed the ceval() problem.
 282
 283      Just "volatile SCM workaround_for_gcc_295 = lst" is enough to avoid the
 284      problem, without even using that variable.  The "w=w" is just to
 285      prevent a warning about it being unused.
 286      */
 287 #if defined (__GNUC__) && __GNUC__ == 2 && __GNUC_MINOR__ == 95
 288   volatile SCM workaround_for_gcc_295 = x;
 289   workaround_for_gcc_295 = workaround_for_gcc_295;
 290 #endif
 291
 292   return SCM_I_CONSP (x);
 293 }
 294
 295
 296 /* Port I/O.  */
 297
 298 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
 299 SCM_C_EXTERN_INLINE
 300 #endif
 301 int
 302 scm_get_byte_or_eof (SCM port)
 303 {
 304   int c;
 305   scm_t_port *pt = SCM_PTAB_ENTRY (port);
 306
 307   if (pt->rw_active == SCM_PORT_WRITE)
 308     /* may be marginally faster than calling scm_flush.  */
 309     scm_ptobs[SCM_PTOBNUM (port)].flush (port);
 310
 311   if (pt->rw_random)
 312     pt->rw_active = SCM_PORT_READ;
 313
 314   if (pt->read_pos >= pt->read_end)
 315     {
 316       if (scm_fill_input (port) == EOF)
 317         return EOF;
 318     }
 319
 320   c = *(pt->read_pos++);
 321
 322   return c;
 323 }
 324
 325 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
 326 SCM_C_EXTERN_INLINE
 327 #endif
 328 void
 329 scm_putc (char c, SCM port)
 330 {
 331   SCM_ASSERT_TYPE (SCM_OPOUTPORTP (port), port, 0, NULL, "output port");
 332   scm_lfwrite (&c, 1, port);
 333 }
 334
 335 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
 336 SCM_C_EXTERN_INLINE
 337 #endif
 338 void
 339 scm_puts (const char *s, SCM port)
 340 {
 341   SCM_ASSERT_TYPE (SCM_OPOUTPORTP (port), port, 0, NULL, "output port");
 342   scm_lfwrite (s, strlen (s), port);
 343 }
 344
 345
 346 #endif
 347 #endif