libguile/frames.c

   1 /* Copyright (C) 2001, 2009, 2010, 2011, 2012 Free Software Foundation, Inc.
   2  *
   3  * This library is free software; you can redistribute it and/or
   4  * modify it under the terms of the GNU Lesser General Public License
   5  * as published by the Free Software Foundation; either version 3 of
   6  * the License, or (at your option) any later version.
   7  *
   8  * This library is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * Lesser General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public
  14  * License along with this library; if not, write to the Free Software
  15  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  16  * 02110-1301 USA
  17  */
  18
  19 #if HAVE_CONFIG_H
  20 #  include <config.h>
  21 #endif
  22
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include "_scm.h"
  26 #include "frames.h"
  27 #include <verify.h>
  28
  29 /* Make sure assumptions on the layout of `struct scm_vm_frame' hold.  */
  30 verify (sizeof (SCM) == sizeof (SCM *));
  31 verify (sizeof (struct scm_vm_frame) == 5 * sizeof (SCM));
  32 verify (offsetof (struct scm_vm_frame, dynamic_link) == 0);
  33
  34 \f
  35 #define RELOC(frame, val)                               \
  36   (((SCM *) (val)) + SCM_VM_FRAME_OFFSET (frame))
  37
  38 SCM
  39 scm_c_make_frame (SCM stack_holder, SCM *fp, SCM *sp,
  40                   scm_t_uint8 *ip, scm_t_ptrdiff offset)
  41 {
  42   struct scm_frame *p = scm_gc_malloc (sizeof (struct scm_frame),
  43                                        "vmframe");
  44   p->stack_holder = stack_holder;
  45   p->fp = fp;
  46   p->sp = sp;
  47   p->ip = ip;
  48   p->offset = offset;
  49   return scm_cell (scm_tc7_frame, (scm_t_bits)p);
  50 }
  51
  52 void
  53 scm_i_frame_print (SCM frame, SCM port, scm_print_state *pstate)
  54 {
  55   scm_puts_unlocked ("#<frame ", port);
  56   scm_uintprint (SCM_UNPACK (frame), 16, port);
  57   scm_putc_unlocked (' ', port);
  58   scm_write (scm_frame_procedure (frame), port);
  59   /* don't write args, they can get us into trouble. */
  60   scm_puts_unlocked (">", port);
  61 }
  62
  63 \f
  64 /* Scheme interface */
  65
  66 SCM_DEFINE (scm_frame_p, "frame?", 1, 0, 0,
  67             (SCM obj),
  68             "")
  69 #define FUNC_NAME s_scm_frame_p
  70 {
  71   return scm_from_bool (SCM_VM_FRAME_P (obj));
  72 }
  73 #undef FUNC_NAME
  74
  75 SCM_DEFINE (scm_frame_procedure, "frame-procedure", 1, 0, 0,
  76             (SCM frame),
  77             "")
  78 #define FUNC_NAME s_scm_frame_procedure
  79 {
  80   SCM_VALIDATE_VM_FRAME (1, frame);
  81   return SCM_FRAME_PROGRAM (SCM_VM_FRAME_FP (frame));
  82 }
  83 #undef FUNC_NAME
  84
  85 SCM_DEFINE (scm_frame_arguments, "frame-arguments", 1, 0, 0,
  86             (SCM frame),
  87             "")
  88 #define FUNC_NAME s_scm_frame_arguments
  89 {
  90   static SCM var = SCM_BOOL_F;
  91
  92   SCM_VALIDATE_VM_FRAME (1, frame);
  93
  94   if (scm_is_false (var))
  95     var = scm_c_module_lookup (scm_c_resolve_module ("system vm frame"),
  96                                "frame-arguments");
  97
  98   return scm_call_1 (SCM_VARIABLE_REF (var), frame);
  99 }
 100 #undef FUNC_NAME
 101
 102 SCM_DEFINE (scm_frame_source, "frame-source", 1, 0, 0,
 103             (SCM frame),
 104             "")
 105 #define FUNC_NAME s_scm_frame_source
 106 {
 107   SCM proc;
 108
 109   SCM_VALIDATE_VM_FRAME (1, frame);
 110
 111   proc = scm_frame_procedure (frame);
 112
 113   if (SCM_PROGRAM_P (proc))
 114     return scm_program_source (scm_frame_procedure (frame),
 115                                scm_frame_instruction_pointer (frame),
 116                                SCM_UNDEFINED);
 117
 118   return SCM_BOOL_F;
 119 }
 120 #undef FUNC_NAME
 121
 122 /* The number of locals would be a simple thing to compute, if it weren't for
 123    the presence of not-yet-active frames on the stack. So we have a cheap
 124    heuristic to detect not-yet-active frames, and skip over them. Perhaps we
 125    should represent them more usefully.
 126 */
 127 SCM_DEFINE (scm_frame_num_locals, "frame-num-locals", 1, 0, 0,
 128             (SCM frame),
 129             "")
 130 #define FUNC_NAME s_scm_frame_num_locals
 131 {
 132   SCM *sp, *p;
 133   unsigned int n = 0;
 134
 135   SCM_VALIDATE_VM_FRAME (1, frame);
 136
 137   sp = SCM_VM_FRAME_SP (frame);
 138   p = SCM_FRAME_STACK_ADDRESS (SCM_VM_FRAME_FP (frame));
 139   while (p <= sp)
 140     {
 141       if (SCM_UNPACK (p[0]) == 0)
 142         /* skip over not-yet-active frame */
 143         p += 3;
 144       else
 145         {
 146           p++;
 147           n++;
 148         }
 149     }
 150   return scm_from_uint (n);
 151 }
 152 #undef FUNC_NAME
 153
 154 /* Need same not-yet-active frame logic here as in frame-num-locals */
 155 SCM_DEFINE (scm_frame_local_ref, "frame-local-ref", 2, 0, 0,
 156             (SCM frame, SCM index),
 157             "")
 158 #define FUNC_NAME s_scm_frame_local_ref
 159 {
 160   SCM *sp, *p;
 161   unsigned int n = 0;
 162   unsigned int i;
 163
 164   SCM_VALIDATE_VM_FRAME (1, frame);
 165   SCM_VALIDATE_UINT_COPY (2, index, i);
 166
 167   sp = SCM_VM_FRAME_SP (frame);
 168   p = SCM_FRAME_STACK_ADDRESS (SCM_VM_FRAME_FP (frame));
 169   while (p <= sp)
 170     {
 171       if (SCM_UNPACK (p[0]) == 0)
 172         /* skip over not-yet-active frame */
 173         p += 3;
 174       else if (n == i)
 175         return *p;
 176       else
 177         {
 178           p++;
 179           n++;
 180         }
 181     }
 182   SCM_OUT_OF_RANGE (SCM_ARG2, index);
 183 }
 184 #undef FUNC_NAME
 185
 186 /* Need same not-yet-active frame logic here as in frame-num-locals */
 187 SCM_DEFINE (scm_frame_local_set_x, "frame-local-set!", 3, 0, 0,
 188             (SCM frame, SCM index, SCM val),
 189             "")
 190 #define FUNC_NAME s_scm_frame_local_set_x
 191 {
 192   SCM *sp, *p;
 193   unsigned int n = 0;
 194   unsigned int i;
 195
 196   SCM_VALIDATE_VM_FRAME (1, frame);
 197   SCM_VALIDATE_UINT_COPY (2, index, i);
 198
 199   sp = SCM_VM_FRAME_SP (frame);
 200   p = SCM_FRAME_STACK_ADDRESS (SCM_VM_FRAME_FP (frame));
 201   while (p <= sp)
 202     {
 203       if (SCM_UNPACK (p[0]) == 0)
 204         /* skip over not-yet-active frame */
 205         p += 3;
 206       else if (n == i)
 207         {
 208           *p = val;
 209           return SCM_UNSPECIFIED;
 210         }
 211       else
 212         {
 213           p++;
 214           n++;
 215         }
 216     }
 217   SCM_OUT_OF_RANGE (SCM_ARG2, index);
 218 }
 219 #undef FUNC_NAME
 220
 221 SCM_DEFINE (scm_frame_address, "frame-address", 1, 0, 0,
 222             (SCM frame),
 223             "Return the frame pointer for @var{frame}.")
 224 #define FUNC_NAME s_scm_frame_address
 225 {
 226   SCM_VALIDATE_VM_FRAME (1, frame);
 227   return scm_from_unsigned_integer ((scm_t_bits) SCM_VM_FRAME_FP (frame));
 228 }
 229 #undef FUNC_NAME
 230
 231 SCM_DEFINE (scm_frame_stack_pointer, "frame-stack-pointer", 1, 0, 0,
 232             (SCM frame),
 233             "")
 234 #define FUNC_NAME s_scm_frame_stack_pointer
 235 {
 236   SCM_VALIDATE_VM_FRAME (1, frame);
 237
 238   return scm_from_unsigned_integer ((scm_t_bits) SCM_VM_FRAME_SP (frame));
 239 }
 240 #undef FUNC_NAME
 241
 242 SCM_DEFINE (scm_frame_instruction_pointer, "frame-instruction-pointer", 1, 0, 0,
 243             (SCM frame),
 244             "")
 245 #define FUNC_NAME s_scm_frame_instruction_pointer
 246 {
 247   SCM program;
 248   const struct scm_objcode *c_objcode;
 249
 250   SCM_VALIDATE_VM_FRAME (1, frame);
 251   program = scm_frame_procedure (frame);
 252
 253   if (!SCM_PROGRAM_P (program))
 254     return SCM_INUM0;
 255
 256   c_objcode = SCM_PROGRAM_DATA (program);
 257   return scm_from_unsigned_integer ((SCM_VM_FRAME_IP (frame)
 258                                      - SCM_C_OBJCODE_BASE (c_objcode)));
 259 }
 260 #undef FUNC_NAME
 261
 262 SCM_DEFINE (scm_frame_return_address, "frame-return-address", 1, 0, 0,
 263             (SCM frame),
 264             "")
 265 #define FUNC_NAME s_scm_frame_return_address
 266 {
 267   SCM_VALIDATE_VM_FRAME (1, frame);
 268   return scm_from_unsigned_integer ((scm_t_bits)
 269                                     (SCM_FRAME_RETURN_ADDRESS
 270                                      (SCM_VM_FRAME_FP (frame))));
 271 }
 272 #undef FUNC_NAME
 273
 274 SCM_DEFINE (scm_frame_mv_return_address, "frame-mv-return-address", 1, 0, 0,
 275             (SCM frame),
 276             "")
 277 #define FUNC_NAME s_scm_frame_mv_return_address
 278 {
 279   SCM_VALIDATE_VM_FRAME (1, frame);
 280   return scm_from_unsigned_integer ((scm_t_bits)
 281                                     (SCM_FRAME_MV_RETURN_ADDRESS
 282                                      (SCM_VM_FRAME_FP (frame))));
 283 }
 284 #undef FUNC_NAME
 285
 286 SCM_DEFINE (scm_frame_dynamic_link, "frame-dynamic-link", 1, 0, 0,
 287             (SCM frame),
 288             "")
 289 #define FUNC_NAME s_scm_frame_dynamic_link
 290 {
 291   SCM_VALIDATE_VM_FRAME (1, frame);
 292   /* fixme: munge fp if holder is a continuation */
 293   return scm_from_ulong
 294     ((unsigned long)
 295      RELOC (frame,
 296             SCM_FRAME_DYNAMIC_LINK (SCM_VM_FRAME_FP (frame))));
 297 }
 298 #undef FUNC_NAME
 299
 300 SCM_DEFINE (scm_frame_previous, "frame-previous", 1, 0, 0,
 301             (SCM frame),
 302             "")
 303 #define FUNC_NAME s_scm_frame_previous
 304 {
 305   SCM *this_fp, *new_fp, *new_sp;
 306   SCM proc;
 307
 308   SCM_VALIDATE_VM_FRAME (1, frame);
 309
 310  again:
 311   this_fp = SCM_VM_FRAME_FP (frame);
 312   new_fp = SCM_FRAME_DYNAMIC_LINK (this_fp);
 313   if (new_fp)
 314     {
 315       new_fp = RELOC (frame, new_fp);
 316       new_sp = SCM_FRAME_LOWER_ADDRESS (this_fp) - 1;
 317       frame = scm_c_make_frame (SCM_VM_FRAME_STACK_HOLDER (frame),
 318                                 new_fp, new_sp,
 319                                 SCM_FRAME_RETURN_ADDRESS (this_fp),
 320                                 SCM_VM_FRAME_OFFSET (frame));
 321       proc = scm_frame_procedure (frame);
 322
 323       if (SCM_PROGRAM_P (proc) && SCM_PROGRAM_IS_BOOT (proc))
 324         goto again;
 325       else
 326         return frame;
 327     }
 328   else
 329     return SCM_BOOL_F;
 330 }
 331 #undef FUNC_NAME
 332
 333 \f
 334 void
 335 scm_init_frames (void)
 336 {
 337 #ifndef SCM_MAGIC_SNARFER
 338 #include "libguile/frames.x"
 339 #endif
 340 }
 341
 342 /*
 343   Local Variables:
 344   c-file-style: "gnu"
 345   End:
 346 */