libguile/frames.c

   1 /* Copyright (C) 2001, 2009 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 "vm-bootstrap.h"
  27 #include "frames.h"
  28
  29 \f
  30 scm_t_bits scm_tc16_frame;
  31
  32 #define RELOC(frame, val) (val + SCM_VM_FRAME_OFFSET (frame))
  33
  34 SCM
  35 scm_c_make_frame (SCM stack_holder, SCM *fp, SCM *sp,
  36                   scm_t_uint8 *ip, scm_t_ptrdiff offset)
  37 {
  38   struct scm_frame *p = scm_gc_malloc (sizeof (struct scm_frame),
  39                                        "vmframe");
  40   p->stack_holder = stack_holder;
  41   p->fp = fp;
  42   p->sp = sp;
  43   p->ip = ip;
  44   p->offset = offset;
  45   SCM_RETURN_NEWSMOB (scm_tc16_frame, p);
  46 }
  47
  48 static int
  49 frame_print (SCM frame, SCM port, scm_print_state *pstate)
  50 {
  51   scm_puts ("#<frame ", port);
  52   scm_uintprint (SCM_UNPACK (frame), 16, port);
  53   scm_putc (' ', port);
  54   scm_write (scm_frame_procedure (frame), port);
  55   /* don't write args, they can get us into trouble. */
  56   scm_puts (">", port);
  57
  58   return 1;
  59 }
  60
  61 \f
  62 /* Scheme interface */
  63
  64 SCM_DEFINE (scm_frame_p, "frame?", 1, 0, 0,
  65             (SCM obj),
  66             "")
  67 #define FUNC_NAME s_scm_frame_p
  68 {
  69   return scm_from_bool (SCM_VM_FRAME_P (obj));
  70 }
  71 #undef FUNC_NAME
  72
  73 SCM_DEFINE (scm_frame_procedure, "frame-procedure", 1, 0, 0,
  74             (SCM frame),
  75             "")
  76 #define FUNC_NAME s_scm_frame_procedure
  77 {
  78   SCM_VALIDATE_VM_FRAME (1, frame);
  79   return SCM_FRAME_PROGRAM (SCM_VM_FRAME_FP (frame));
  80 }
  81 #undef FUNC_NAME
  82
  83 SCM_DEFINE (scm_frame_arguments, "frame-arguments", 1, 0, 0,
  84             (SCM frame),
  85             "")
  86 #define FUNC_NAME s_scm_frame_arguments
  87 {
  88   static SCM var = SCM_BOOL_F;
  89
  90   SCM_VALIDATE_VM_FRAME (1, frame);
  91
  92   if (scm_is_false (var))
  93     var = scm_c_module_lookup (scm_c_resolve_module ("system vm frame"),
  94                                "frame-arguments");
  95
  96   return scm_call_1 (SCM_VARIABLE_REF (var), frame);
  97 }
  98 #undef FUNC_NAME
  99
 100 SCM_DEFINE (scm_frame_source, "frame-source", 1, 0, 0,
 101             (SCM frame),
 102             "")
 103 #define FUNC_NAME s_scm_frame_source
 104 {
 105   SCM *fp;
 106   struct scm_objcode *bp;
 107
 108   SCM_VALIDATE_VM_FRAME (1, frame);
 109
 110   fp = SCM_VM_FRAME_FP (frame);
 111   bp = SCM_PROGRAM_DATA (SCM_FRAME_PROGRAM (fp));
 112
 113   return scm_c_program_source (SCM_FRAME_PROGRAM (fp),
 114                                SCM_VM_FRAME_IP (frame)
 115                                - SCM_C_OBJCODE_BASE (bp));
 116 }
 117 #undef FUNC_NAME
 118
 119 /* The number of locals would be a simple thing to compute, if it weren't for
 120    the presence of not-yet-active frames on the stack. So we have a cheap
 121    heuristic to detect not-yet-active frames, and skip over them. Perhaps we
 122    should represent them more usefully.
 123 */
 124 SCM_DEFINE (scm_frame_num_locals, "frame-num-locals", 1, 0, 0,
 125             (SCM frame),
 126             "")
 127 #define FUNC_NAME s_scm_frame_num_locals
 128 {
 129   SCM *sp, *p;
 130   unsigned int n = 0;
 131
 132   SCM_VALIDATE_VM_FRAME (1, frame);
 133
 134   sp = SCM_VM_FRAME_SP (frame);
 135   p = SCM_FRAME_STACK_ADDRESS (SCM_VM_FRAME_FP (frame));
 136   while (p <= sp)
 137     {
 138       if (p + 1 < sp && p[1] == (SCM)0)
 139         /* skip over not-yet-active frame */
 140         p += 3;
 141       else
 142         {
 143           p++;
 144           n++;
 145         }
 146     }
 147   return scm_from_uint (n);
 148 }
 149 #undef FUNC_NAME
 150
 151 /* Need same not-yet-active frame logic here as in frame-num-locals */
 152 SCM_DEFINE (scm_frame_local_ref, "frame-local-ref", 2, 0, 0,
 153             (SCM frame, SCM index),
 154             "")
 155 #define FUNC_NAME s_scm_frame_local_ref
 156 {
 157   SCM *sp, *p;
 158   unsigned int n = 0;
 159   unsigned int i;
 160
 161   SCM_VALIDATE_VM_FRAME (1, frame);
 162   SCM_VALIDATE_UINT_COPY (2, index, i);
 163
 164   sp = SCM_VM_FRAME_SP (frame);
 165   p = SCM_FRAME_STACK_ADDRESS (SCM_VM_FRAME_FP (frame));
 166   while (p <= sp)
 167     {
 168       if (p + 1 < sp && p[1] == (SCM)0)
 169         /* skip over not-yet-active frame */
 170         p += 3;
 171       else if (n == i)
 172         return *p;
 173       else
 174         {
 175           p++;
 176           n++;
 177         }
 178     }
 179   SCM_OUT_OF_RANGE (SCM_ARG2, index);
 180 }
 181 #undef FUNC_NAME
 182
 183 /* Need same not-yet-active frame logic here as in frame-num-locals */
 184 SCM_DEFINE (scm_frame_local_set_x, "frame-local-set!", 3, 0, 0,
 185             (SCM frame, SCM index, SCM val),
 186             "")
 187 #define FUNC_NAME s_scm_frame_local_set_x
 188 {
 189   SCM *sp, *p;
 190   unsigned int n = 0;
 191   unsigned int i;
 192
 193   SCM_VALIDATE_VM_FRAME (1, frame);
 194   SCM_VALIDATE_UINT_COPY (2, index, i);
 195
 196   sp = SCM_VM_FRAME_SP (frame);
 197   p = SCM_FRAME_STACK_ADDRESS (SCM_VM_FRAME_FP (frame));
 198   while (p <= sp)
 199     {
 200       if (p + 1 < sp && p[1] == (SCM)0)
 201         /* skip over not-yet-active frame */
 202         p += 3;
 203       else if (n == i)
 204         {
 205           *p = val;
 206           return SCM_UNSPECIFIED;
 207         }
 208       else
 209         {
 210           p++;
 211           n++;
 212         }
 213     }
 214   SCM_OUT_OF_RANGE (SCM_ARG2, index);
 215 }
 216 #undef FUNC_NAME
 217
 218 SCM_DEFINE (scm_frame_instruction_pointer, "frame-instruction-pointer", 1, 0, 0,
 219             (SCM frame),
 220             "")
 221 #define FUNC_NAME s_scm_frame_instruction_pointer
 222 {
 223   const struct scm_objcode *c_objcode;
 224
 225   SCM_VALIDATE_VM_FRAME (1, frame);
 226
 227   c_objcode = SCM_PROGRAM_DATA (scm_frame_procedure (frame));
 228   return scm_from_ulong ((unsigned long)
 229                          (SCM_VM_FRAME_IP (frame)
 230                           - SCM_C_OBJCODE_BASE (c_objcode)));
 231 }
 232 #undef FUNC_NAME
 233
 234 SCM_DEFINE (scm_frame_return_address, "frame-return-address", 1, 0, 0,
 235             (SCM frame),
 236             "")
 237 #define FUNC_NAME s_scm_frame_return_address
 238 {
 239   SCM_VALIDATE_VM_FRAME (1, frame);
 240   return scm_from_ulong ((unsigned long)
 241                          (SCM_FRAME_RETURN_ADDRESS
 242                           (SCM_VM_FRAME_FP (frame))));
 243 }
 244 #undef FUNC_NAME
 245
 246 SCM_DEFINE (scm_frame_mv_return_address, "frame-mv-return-address", 1, 0, 0,
 247             (SCM frame),
 248             "")
 249 #define FUNC_NAME s_scm_frame_mv_return_address
 250 {
 251   SCM_VALIDATE_VM_FRAME (1, frame);
 252   return scm_from_ulong ((unsigned long)
 253                          (SCM_FRAME_MV_RETURN_ADDRESS
 254                           (SCM_VM_FRAME_FP (frame))));
 255 }
 256 #undef FUNC_NAME
 257
 258 SCM_DEFINE (scm_frame_dynamic_link, "frame-dynamic-link", 1, 0, 0,
 259             (SCM frame),
 260             "")
 261 #define FUNC_NAME s_scm_frame_dynamic_link
 262 {
 263   SCM_VALIDATE_VM_FRAME (1, frame);
 264   /* fixme: munge fp if holder is a continuation */
 265   return scm_from_ulong
 266     ((unsigned long)
 267      RELOC (frame,
 268             SCM_FRAME_DYNAMIC_LINK (SCM_VM_FRAME_FP (frame))));
 269 }
 270 #undef FUNC_NAME
 271
 272 SCM_DEFINE (scm_frame_previous, "frame-previous", 1, 0, 0,
 273             (SCM frame),
 274             "")
 275 #define FUNC_NAME s_scm_frame_previous
 276 {
 277   SCM *this_fp, *new_fp, *new_sp;
 278
 279   SCM_VALIDATE_VM_FRAME (1, frame);
 280
 281  again:
 282   this_fp = SCM_VM_FRAME_FP (frame);
 283   new_fp = SCM_FRAME_DYNAMIC_LINK (this_fp);
 284   if (new_fp)
 285     { new_fp = RELOC (frame, new_fp);
 286       new_sp = SCM_FRAME_LOWER_ADDRESS (this_fp) - 1;
 287       frame = scm_c_make_frame (SCM_VM_FRAME_STACK_HOLDER (frame),
 288                                 new_fp, new_sp,
 289                                 SCM_FRAME_RETURN_ADDRESS (this_fp),
 290                                 SCM_VM_FRAME_OFFSET (frame));
 291       if (SCM_PROGRAM_IS_BOOT (scm_frame_procedure (frame)))
 292         goto again;
 293       else
 294         return frame;
 295     }
 296   else
 297     return SCM_BOOL_F;
 298 }
 299 #undef FUNC_NAME
 300
 301 \f
 302 void
 303 scm_bootstrap_frames (void)
 304 {
 305   scm_tc16_frame = scm_make_smob_type ("frame", 0);
 306   scm_set_smob_print (scm_tc16_frame, frame_print);
 307 }
 308
 309 void
 310 scm_init_frames (void)
 311 {
 312 #ifndef SCM_MAGIC_SNARFER
 313 #include "libguile/frames.x"
 314 #endif
 315 }
 316
 317 /*
 318   Local Variables:
 319   c-file-style: "gnu"
 320   End:
 321 */