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   /*
 123     We update scm_cells_allocated from this function. If we don't
 124     update this explicitly, we will have to walk a freelist somewhere
 125     later on, which seems a lot more expensive.
 126    */
 127   scm_cells_allocated += 1;
 128
 129 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 130     if (scm_debug_cell_accesses_p)
 131       {
 132         if (SCM_GC_MARK_P (z))
 133           {
 134             fprintf(stderr, "scm_cell tried to allocate a marked cell.\n");
 135             abort();
 136           }
 137         else if (SCM_GC_CELL_WORD(z, 0) != scm_tc_free_cell)
 138           {
 139             fprintf(stderr, "cell from freelist is not a free cell.\n");
 140             abort();
 141           }
 142       }
 143
 144     /*
 145       Always set mark. Otherwise cells that are alloced before
 146       scm_debug_cell_accesses_p is toggled seem invalid.
 147     */
 148     SCM_SET_GC_MARK (z);
 149
 150     /*
 151       TODO: figure out if this use of mark bits is valid with
 152       threading. What if another thread is doing GC at this point
 153       ... ?
 154      */
 155
 156 #endif
 157
 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, cdr);
 165   SCM_GC_SET_CELL_WORD (z, 0, car);
 166
 167 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 168   if (scm_expensive_debug_cell_accesses_p )
 169     scm_i_expensive_validation_check (z);
 170 #endif
 171
 172   return z;
 173 }
 174
 175 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
 176 SCM_C_EXTERN_INLINE
 177 #endif
 178 SCM
 179 scm_double_cell (scm_t_bits car, scm_t_bits cbr,
 180                  scm_t_bits ccr, scm_t_bits cdr)
 181 {
 182   SCM z;
 183   SCM *freelist = SCM_FREELIST_LOC (scm_i_freelist2);
 184
 185   if (scm_is_null (*freelist))
 186     z = scm_gc_for_newcell (&scm_i_master_freelist2, freelist);
 187   else
 188     {
 189       z = *freelist;
 190       *freelist = SCM_FREE_CELL_CDR (*freelist);
 191     }
 192
 193   scm_cells_allocated += 2;
 194
 195   /* Initialize the type slot last so that the cell is ignored by the
 196      GC until it is completely initialized.  This is only relevant
 197      when the GC can actually run during this code, which it can't
 198      since the GC only runs when all other threads are stopped.
 199   */
 200   SCM_GC_SET_CELL_WORD (z, 1, cbr);
 201   SCM_GC_SET_CELL_WORD (z, 2, ccr);
 202   SCM_GC_SET_CELL_WORD (z, 3, cdr);
 203   SCM_GC_SET_CELL_WORD (z, 0, car);
 204
 205 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 206   if (scm_debug_cell_accesses_p)
 207     {
 208       if (SCM_GC_MARK_P (z))
 209         {
 210           fprintf(stderr,
 211                   "scm_double_cell tried to allocate a marked cell.\n");
 212           abort();
 213         }
 214     }
 215
 216   /* see above. */
 217   SCM_SET_GC_MARK (z);
 218
 219 #endif
 220
 221   /* When this function is inlined, it's possible that the last
 222      SCM_GC_SET_CELL_WORD above will be adjacent to a following
 223      initialization of z.  E.g., it occurred in scm_make_real.  GCC
 224      from around version 3 (e.g., certainly 3.2) began taking
 225      advantage of strict C aliasing rules which say that it's OK to
 226      interchange the initialization above and the one below when the
 227      pointer types appear to differ sufficiently.  We don't want that,
 228      of course.  GCC allows this behaviour to be disabled with the
 229      -fno-strict-aliasing option, but would also need to be supplied
 230      by Guile users.  Instead, the following statements prevent the
 231      reordering.
 232    */
 233 #ifdef __GNUC__
 234   __asm__ volatile ("" : : : "memory");
 235 #else
 236   /* portable version, just in case any other compiler does the same
 237      thing.  */
 238   scm_remember_upto_here_1 (z);
 239 #endif
 240
 241   return z;
 242 }
 243
 244 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
 245 SCM_C_EXTERN_INLINE
 246 #endif
 247 SCM
 248 scm_array_handle_ref (scm_t_array_handle *h, ssize_t p)
 249 {
 250   return h->ref (h, p);
 251 }
 252
 253 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
 254 SCM_C_EXTERN_INLINE
 255 #endif
 256 void
 257 scm_array_handle_set (scm_t_array_handle *h, ssize_t p, SCM v)
 258 {
 259   h->set (h, p, v);
 260 }
 261
 262 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
 263 SCM_C_EXTERN_INLINE
 264 #endif
 265 int
 266 scm_is_pair (SCM x)
 267 {
 268   /* The following "workaround_for_gcc_295" avoids bad code generated by
 269      i386 gcc 2.95.4 (the Debian packaged 2.95.4-24 at least).
 270
 271      Under the default -O2 the inlined SCM_I_CONSP test gets "optimized" so
 272      the fetch of the tag word from x is done before confirming it's a
 273      non-immediate (SCM_NIMP).  Needless to say that bombs badly if x is a
 274      immediate.  This was seen to afflict scm_srfi1_split_at and something
 275      deep in the bowels of ceval().  In both cases segvs resulted from
 276      deferencing a random immediate value.  srfi-1.test exposes the problem
 277      through a short list, the immediate being SCM_EOL in that case.
 278      Something in syntax.test exposed the ceval() problem.
 279
 280      Just "volatile SCM workaround_for_gcc_295 = lst" is enough to avoid the
 281      problem, without even using that variable.  The "w=w" is just to
 282      prevent a warning about it being unused.
 283      */
 284 #if defined (__GNUC__) && __GNUC__ == 2 && __GNUC_MINOR__ == 95
 285   volatile SCM workaround_for_gcc_295 = x;
 286   workaround_for_gcc_295 = workaround_for_gcc_295;
 287 #endif
 288
 289   return SCM_I_CONSP (x);
 290 }
 291
 292
 293 /* Port I/O.  */
 294
 295 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
 296 SCM_C_EXTERN_INLINE
 297 #endif
 298 int
 299 scm_getc (SCM port)
 300 {
 301   int c;
 302   scm_t_port *pt = SCM_PTAB_ENTRY (port);
 303
 304   if (pt->rw_active == SCM_PORT_WRITE)
 305     /* may be marginally faster than calling scm_flush.  */
 306     scm_ptobs[SCM_PTOBNUM (port)].flush (port);
 307
 308   if (pt->rw_random)
 309     pt->rw_active = SCM_PORT_READ;
 310
 311   if (pt->read_pos >= pt->read_end)
 312     {
 313       if (scm_fill_input (port) == EOF)
 314         return EOF;
 315     }
 316
 317   c = *(pt->read_pos++);
 318
 319   switch (c)
 320     {
 321       case '\a':
 322         break;
 323       case '\b':
 324         SCM_DECCOL (port);
 325         break;
 326       case '\n':
 327         SCM_INCLINE (port);
 328         break;
 329       case '\r':
 330         SCM_ZEROCOL (port);
 331         break;
 332       case '\t':
 333         SCM_TABCOL (port);
 334         break;
 335       default:
 336         SCM_INCCOL (port);
 337         break;
 338     }
 339
 340   return c;
 341 }
 342
 343 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
 344 SCM_C_EXTERN_INLINE
 345 #endif
 346 void
 347 scm_putc (char c, SCM port)
 348 {
 349   SCM_ASSERT_TYPE (SCM_OPOUTPORTP (port), port, 0, NULL, "output port");
 350   scm_lfwrite (&c, 1, port);
 351 }
 352
 353 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
 354 SCM_C_EXTERN_INLINE
 355 #endif
 356 void
 357 scm_puts (const char *s, SCM port)
 358 {
 359   SCM_ASSERT_TYPE (SCM_OPOUTPORTP (port), port, 0, NULL, "output port");
 360   scm_lfwrite (s, strlen (s), port);
 361 }
 362
 363
 364 #endif
 365 #endif