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 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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 <stdio.h>
  29 #include <string.h>
  30
  31 #include "libguile/__scm.h"
  32
  33 #include "libguile/pairs.h"
  34 #include "libguile/gc.h"
  35 #include "libguile/threads.h"
  36 #include "libguile/unif.h"
  37 #include "libguile/ports.h"
  38 #include "libguile/error.h"
  39
  40
  41 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
  42
  43 /* GCC has `__inline__' in all modes, including strict ansi.  GCC 4.3 and
  44    above with `-std=c99' or `-std=gnu99' implements ISO C99 inline semantics,
  45    unless `-fgnu89-inline' is used.  Here we want GNU "extern inline"
  46    semantics, hence the `__gnu_inline__' attribute, in accordance with:
  47    http://gcc.gnu.org/gcc-4.3/porting_to.html .
  48
  49    With GCC 4.2, `__GNUC_STDC_INLINE__' is never defined (because C99 inline
  50    semantics are not supported), but a warning is issued in C99 mode if
  51    `__gnu_inline__' is not used.
  52
  53    Apple's GCC build >5400 (since Xcode 3.0) doesn't support GNU inline in
  54    C99 mode and doesn't define `__GNUC_STDC_INLINE__'.  Fall back to "static
  55    inline" in that case.  */
  56
  57 # if (defined __GNUC__) && (!(__APPLE_CC__ > 5400 && __STDC_VERSION__ >= 199901L))
  58 #  define SCM_C_USE_EXTERN_INLINE 1
  59 #  if (defined __GNUC_STDC_INLINE__) || (__GNUC__ == 4 && __GNUC_MINOR__ == 2)
  60 #   define SCM_C_EXTERN_INLINE                                  \
  61            extern __inline__ __attribute__ ((__gnu_inline__))
  62 #  else
  63 #   define SCM_C_EXTERN_INLINE extern __inline__
  64 #  endif
  65 # elif (defined SCM_C_INLINE)
  66 #  define SCM_C_EXTERN_INLINE static SCM_C_INLINE
  67 # endif
  68
  69 #endif /* SCM_INLINE_C_INCLUDING_INLINE_H */
  70
  71
  72 #if (!defined SCM_C_INLINE) || (defined SCM_INLINE_C_INCLUDING_INLINE_H) \
  73     || (defined SCM_C_USE_EXTERN_INLINE)
  74
  75 /* The `extern' declarations.  They should only appear when used from
  76    "inline.c", when `inline' is not supported at all or when "extern inline"
  77    is used.  */
  78
  79 SCM_API SCM scm_cell (scm_t_bits car, scm_t_bits cdr);
  80 SCM_API SCM scm_double_cell (scm_t_bits car, scm_t_bits cbr,
  81                              scm_t_bits ccr, scm_t_bits cdr);
  82
  83 SCM_API SCM scm_array_handle_ref (scm_t_array_handle *h, ssize_t pos);
  84 SCM_API void scm_array_handle_set (scm_t_array_handle *h, ssize_t pos, SCM val);
  85
  86 SCM_API int scm_is_pair (SCM x);
  87
  88 SCM_API int scm_getc (SCM port);
  89 SCM_API void scm_putc (char c, SCM port);
  90 SCM_API void scm_puts (const char *str_data, SCM port);
  91
  92 #endif
  93
  94
  95 #if defined SCM_C_EXTERN_INLINE || defined SCM_INLINE_C_INCLUDING_INLINE_H
  96 /* either inlining, or being included from inline.c.  We use (and
  97    repeat) this long #if test here and below so that we don't have to
  98    introduce any extraneous symbols into the public namespace.  We
  99    only need SCM_C_INLINE to be seen publically . */
 100
 101 extern unsigned scm_newcell2_count;
 102 extern unsigned scm_newcell_count;
 103
 104
 105 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
 106 SCM_C_EXTERN_INLINE
 107 #endif
 108 SCM
 109 scm_cell (scm_t_bits car, scm_t_bits cdr)
 110 {
 111   SCM z;
 112   SCM *freelist = SCM_FREELIST_LOC (scm_i_freelist);
 113
 114   if (scm_is_null (*freelist))
 115     z = scm_gc_for_newcell (&scm_i_master_freelist, freelist);
 116   else
 117     {
 118       z = *freelist;
 119       *freelist = SCM_FREE_CELL_CDR (*freelist);
 120     }
 121
 122 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 123     if (scm_debug_cell_accesses_p)
 124       {
 125         if (SCM_GC_MARK_P (z))
 126           {
 127             fprintf(stderr, "scm_cell tried to allocate a marked cell.\n");
 128             abort();
 129           }
 130         else if (SCM_GC_CELL_WORD(z, 0) != scm_tc_free_cell)
 131           {
 132             fprintf(stderr, "cell from freelist is not a free cell.\n");
 133             abort();
 134           }
 135       }
 136
 137 #if (SCM_DEBUG_MARKING_API == 0)
 138     /*
 139       Always set mark. Otherwise cells that are alloced before
 140       scm_debug_cell_accesses_p is toggled seem invalid.
 141     */
 142     SCM_SET_GC_MARK (z);
 143 #endif /* SCM_DEBUG_MARKING_API */
 144
 145     /*
 146       TODO: figure out if this use of mark bits is valid with
 147       threading. What if another thread is doing GC at this point
 148       ... ?
 149      */
 150 #endif
 151
 152
 153   /* Initialize the type slot last so that the cell is ignored by the
 154      GC until it is completely initialized.  This is only relevant
 155      when the GC can actually run during this code, which it can't
 156      since the GC only runs when all other threads are stopped.
 157   */
 158   SCM_GC_SET_CELL_WORD (z, 1, cdr);
 159   SCM_GC_SET_CELL_WORD (z, 0, car);
 160
 161 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 162   if (scm_expensive_debug_cell_accesses_p )
 163     scm_i_expensive_validation_check (z);
 164 #endif
 165
 166   return z;
 167 }
 168
 169 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
 170 SCM_C_EXTERN_INLINE
 171 #endif
 172 SCM
 173 scm_double_cell (scm_t_bits car, scm_t_bits cbr,
 174                  scm_t_bits ccr, scm_t_bits cdr)
 175 {
 176   SCM z;
 177   SCM *freelist = SCM_FREELIST_LOC (scm_i_freelist2);
 178
 179   if (scm_is_null (*freelist))
 180     z = scm_gc_for_newcell (&scm_i_master_freelist2, freelist);
 181   else
 182     {
 183       z = *freelist;
 184       *freelist = SCM_FREE_CELL_CDR (*freelist);
 185     }
 186
 187   /* Initialize the type slot last so that the cell is ignored by the
 188      GC until it is completely initialized.  This is only relevant
 189      when the GC can actually run during this code, which it can't
 190      since the GC only runs when all other threads are stopped.
 191   */
 192   SCM_GC_SET_CELL_WORD (z, 1, cbr);
 193   SCM_GC_SET_CELL_WORD (z, 2, ccr);
 194   SCM_GC_SET_CELL_WORD (z, 3, cdr);
 195   SCM_GC_SET_CELL_WORD (z, 0, car);
 196
 197 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 198   if (scm_debug_cell_accesses_p)
 199     {
 200       if (SCM_GC_MARK_P (z))
 201         {
 202           fprintf(stderr,
 203                   "scm_double_cell tried to allocate a marked cell.\n");
 204           abort();
 205         }
 206     }
 207 #if (SCM_DEBUG_MARKING_API == 0)
 208   /* see above. */
 209   SCM_SET_GC_MARK (z);
 210 #endif /* SCM_DEBUG_MARKING_API */
 211
 212 #endif
 213
 214   /* When this function is inlined, it's possible that the last
 215      SCM_GC_SET_CELL_WORD above will be adjacent to a following
 216      initialization of z.  E.g., it occurred in scm_make_real.  GCC
 217      from around version 3 (e.g., certainly 3.2) began taking
 218      advantage of strict C aliasing rules which say that it's OK to
 219      interchange the initialization above and the one below when the
 220      pointer types appear to differ sufficiently.  We don't want that,
 221      of course.  GCC allows this behaviour to be disabled with the
 222      -fno-strict-aliasing option, but would also need to be supplied
 223      by Guile users.  Instead, the following statements prevent the
 224      reordering.
 225    */
 226 #ifdef __GNUC__
 227   __asm__ volatile ("" : : : "memory");
 228 #else
 229   /* portable version, just in case any other compiler does the same
 230      thing.  */
 231   scm_remember_upto_here_1 (z);
 232 #endif
 233
 234   return z;
 235 }
 236
 237 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
 238 SCM_C_EXTERN_INLINE
 239 #endif
 240 SCM
 241 scm_array_handle_ref (scm_t_array_handle *h, ssize_t p)
 242 {
 243   return h->ref (h, p);
 244 }
 245
 246 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
 247 SCM_C_EXTERN_INLINE
 248 #endif
 249 void
 250 scm_array_handle_set (scm_t_array_handle *h, ssize_t p, SCM v)
 251 {
 252   h->set (h, p, v);
 253 }
 254
 255 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
 256 SCM_C_EXTERN_INLINE
 257 #endif
 258 int
 259 scm_is_pair (SCM x)
 260 {
 261   /* The following "workaround_for_gcc_295" avoids bad code generated by
 262      i386 gcc 2.95.4 (the Debian packaged 2.95.4-24 at least).
 263
 264      Under the default -O2 the inlined SCM_I_CONSP test gets "optimized" so
 265      the fetch of the tag word from x is done before confirming it's a
 266      non-immediate (SCM_NIMP).  Needless to say that bombs badly if x is a
 267      immediate.  This was seen to afflict scm_srfi1_split_at and something
 268      deep in the bowels of ceval().  In both cases segvs resulted from
 269      deferencing a random immediate value.  srfi-1.test exposes the problem
 270      through a short list, the immediate being SCM_EOL in that case.
 271      Something in syntax.test exposed the ceval() problem.
 272
 273      Just "volatile SCM workaround_for_gcc_295 = lst" is enough to avoid the
 274      problem, without even using that variable.  The "w=w" is just to
 275      prevent a warning about it being unused.
 276      */
 277 #if defined (__GNUC__) && __GNUC__ == 2 && __GNUC_MINOR__ == 95
 278   volatile SCM workaround_for_gcc_295 = x;
 279   workaround_for_gcc_295 = workaround_for_gcc_295;
 280 #endif
 281
 282   return SCM_I_CONSP (x);
 283 }
 284
 285
 286 /* Port I/O.  */
 287
 288 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
 289 SCM_C_EXTERN_INLINE
 290 #endif
 291 int
 292 scm_getc (SCM port)
 293 {
 294   int c;
 295   scm_t_port *pt = SCM_PTAB_ENTRY (port);
 296
 297   if (pt->rw_active == SCM_PORT_WRITE)
 298     /* may be marginally faster than calling scm_flush.  */
 299     scm_ptobs[SCM_PTOBNUM (port)].flush (port);
 300
 301   if (pt->rw_random)
 302     pt->rw_active = SCM_PORT_READ;
 303
 304   if (pt->read_pos >= pt->read_end)
 305     {
 306       if (scm_fill_input (port) == EOF)
 307         return EOF;
 308     }
 309
 310   c = *(pt->read_pos++);
 311
 312   switch (c)
 313     {
 314       case '\a':
 315         break;
 316       case '\b':
 317         SCM_DECCOL (port);
 318         break;
 319       case '\n':
 320         SCM_INCLINE (port);
 321         break;
 322       case '\r':
 323         SCM_ZEROCOL (port);
 324         break;
 325       case '\t':
 326         SCM_TABCOL (port);
 327         break;
 328       default:
 329         SCM_INCCOL (port);
 330         break;
 331     }
 332
 333   return c;
 334 }
 335
 336 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
 337 SCM_C_EXTERN_INLINE
 338 #endif
 339 void
 340 scm_putc (char c, SCM port)
 341 {
 342   SCM_ASSERT_TYPE (SCM_OPOUTPORTP (port), port, 0, NULL, "output port");
 343   scm_lfwrite (&c, 1, port);
 344 }
 345
 346 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
 347 SCM_C_EXTERN_INLINE
 348 #endif
 349 void
 350 scm_puts (const char *s, SCM port)
 351 {
 352   SCM_ASSERT_TYPE (SCM_OPOUTPORTP (port), port, 0, NULL, "output port");
 353   scm_lfwrite (s, strlen (s), port);
 354 }
 355
 356
 357 #endif
 358 #endif