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_VALIDATE_VM_FRAME (1, frame);
 108
 109   return scm_program_source (scm_frame_procedure (frame),
 110                              scm_frame_instruction_pointer (frame),
 111                              SCM_UNDEFINED);
 112 }
 113 #undef FUNC_NAME
 114
 115 /* The number of locals would be a simple thing to compute, if it weren't for
 116    the presence of not-yet-active frames on the stack. So we have a cheap
 117    heuristic to detect not-yet-active frames, and skip over them. Perhaps we
 118    should represent them more usefully.
 119 */
 120 SCM_DEFINE (scm_frame_num_locals, "frame-num-locals", 1, 0, 0,
 121             (SCM frame),
 122             "")
 123 #define FUNC_NAME s_scm_frame_num_locals
 124 {
 125   SCM *sp, *p;
 126   unsigned int n = 0;
 127
 128   SCM_VALIDATE_VM_FRAME (1, frame);
 129
 130   sp = SCM_VM_FRAME_SP (frame);
 131   p = SCM_FRAME_STACK_ADDRESS (SCM_VM_FRAME_FP (frame));
 132   while (p <= sp)
 133     {
 134       if (SCM_UNPACK (p[0]) == 0)
 135         /* skip over not-yet-active frame */
 136         p += 3;
 137       else
 138         {
 139           p++;
 140           n++;
 141         }
 142     }
 143   return scm_from_uint (n);
 144 }
 145 #undef FUNC_NAME
 146
 147 /* Need same not-yet-active frame logic here as in frame-num-locals */
 148 SCM_DEFINE (scm_frame_local_ref, "frame-local-ref", 2, 0, 0,
 149             (SCM frame, SCM index),
 150             "")
 151 #define FUNC_NAME s_scm_frame_local_ref
 152 {
 153   SCM *sp, *p;
 154   unsigned int n = 0;
 155   unsigned int i;
 156
 157   SCM_VALIDATE_VM_FRAME (1, frame);
 158   SCM_VALIDATE_UINT_COPY (2, index, i);
 159
 160   sp = SCM_VM_FRAME_SP (frame);
 161   p = SCM_FRAME_STACK_ADDRESS (SCM_VM_FRAME_FP (frame));
 162   while (p <= sp)
 163     {
 164       if (SCM_UNPACK (p[0]) == 0)
 165         /* skip over not-yet-active frame */
 166         p += 3;
 167       else if (n == i)
 168         return *p;
 169       else
 170         {
 171           p++;
 172           n++;
 173         }
 174     }
 175   SCM_OUT_OF_RANGE (SCM_ARG2, index);
 176 }
 177 #undef FUNC_NAME
 178
 179 /* Need same not-yet-active frame logic here as in frame-num-locals */
 180 SCM_DEFINE (scm_frame_local_set_x, "frame-local-set!", 3, 0, 0,
 181             (SCM frame, SCM index, SCM val),
 182             "")
 183 #define FUNC_NAME s_scm_frame_local_set_x
 184 {
 185   SCM *sp, *p;
 186   unsigned int n = 0;
 187   unsigned int i;
 188
 189   SCM_VALIDATE_VM_FRAME (1, frame);
 190   SCM_VALIDATE_UINT_COPY (2, index, i);
 191
 192   sp = SCM_VM_FRAME_SP (frame);
 193   p = SCM_FRAME_STACK_ADDRESS (SCM_VM_FRAME_FP (frame));
 194   while (p <= sp)
 195     {
 196       if (SCM_UNPACK (p[0]) == 0)
 197         /* skip over not-yet-active frame */
 198         p += 3;
 199       else if (n == i)
 200         {
 201           *p = val;
 202           return SCM_UNSPECIFIED;
 203         }
 204       else
 205         {
 206           p++;
 207           n++;
 208         }
 209     }
 210   SCM_OUT_OF_RANGE (SCM_ARG2, index);
 211 }
 212 #undef FUNC_NAME
 213
 214 SCM_DEFINE (scm_frame_address, "frame-address", 1, 0, 0,
 215             (SCM frame),
 216             "Return the frame pointer for @var{frame}.")
 217 #define FUNC_NAME s_scm_frame_address
 218 {
 219   SCM_VALIDATE_VM_FRAME (1, frame);
 220   return scm_from_unsigned_integer ((scm_t_bits) SCM_VM_FRAME_FP (frame));
 221 }
 222 #undef FUNC_NAME
 223
 224 SCM_DEFINE (scm_frame_stack_pointer, "frame-stack-pointer", 1, 0, 0,
 225             (SCM frame),
 226             "")
 227 #define FUNC_NAME s_scm_frame_stack_pointer
 228 {
 229   SCM_VALIDATE_VM_FRAME (1, frame);
 230
 231   return scm_from_unsigned_integer ((scm_t_bits) SCM_VM_FRAME_SP (frame));
 232 }
 233 #undef FUNC_NAME
 234
 235 SCM_DEFINE (scm_frame_instruction_pointer, "frame-instruction-pointer", 1, 0, 0,
 236             (SCM frame),
 237             "")
 238 #define FUNC_NAME s_scm_frame_instruction_pointer
 239 {
 240   const struct scm_objcode *c_objcode;
 241
 242   SCM_VALIDATE_VM_FRAME (1, frame);
 243
 244   c_objcode = SCM_PROGRAM_DATA (scm_frame_procedure (frame));
 245   return scm_from_unsigned_integer ((SCM_VM_FRAME_IP (frame)
 246                                      - SCM_C_OBJCODE_BASE (c_objcode)));
 247 }
 248 #undef FUNC_NAME
 249
 250 SCM_DEFINE (scm_frame_return_address, "frame-return-address", 1, 0, 0,
 251             (SCM frame),
 252             "")
 253 #define FUNC_NAME s_scm_frame_return_address
 254 {
 255   SCM_VALIDATE_VM_FRAME (1, frame);
 256   return scm_from_unsigned_integer ((scm_t_bits)
 257                                     (SCM_FRAME_RETURN_ADDRESS
 258                                      (SCM_VM_FRAME_FP (frame))));
 259 }
 260 #undef FUNC_NAME
 261
 262 SCM_DEFINE (scm_frame_mv_return_address, "frame-mv-return-address", 1, 0, 0,
 263             (SCM frame),
 264             "")
 265 #define FUNC_NAME s_scm_frame_mv_return_address
 266 {
 267   SCM_VALIDATE_VM_FRAME (1, frame);
 268   return scm_from_unsigned_integer ((scm_t_bits)
 269                                     (SCM_FRAME_MV_RETURN_ADDRESS
 270                                      (SCM_VM_FRAME_FP (frame))));
 271 }
 272 #undef FUNC_NAME
 273
 274 SCM_DEFINE (scm_frame_dynamic_link, "frame-dynamic-link", 1, 0, 0,
 275             (SCM frame),
 276             "")
 277 #define FUNC_NAME s_scm_frame_dynamic_link
 278 {
 279   SCM_VALIDATE_VM_FRAME (1, frame);
 280   /* fixme: munge fp if holder is a continuation */
 281   return scm_from_ulong
 282     ((unsigned long)
 283      RELOC (frame,
 284             SCM_FRAME_DYNAMIC_LINK (SCM_VM_FRAME_FP (frame))));
 285 }
 286 #undef FUNC_NAME
 287
 288 SCM_DEFINE (scm_frame_previous, "frame-previous", 1, 0, 0,
 289             (SCM frame),
 290             "")
 291 #define FUNC_NAME s_scm_frame_previous
 292 {
 293   SCM *this_fp, *new_fp, *new_sp;
 294
 295   SCM_VALIDATE_VM_FRAME (1, frame);
 296
 297  again:
 298   this_fp = SCM_VM_FRAME_FP (frame);
 299   new_fp = SCM_FRAME_DYNAMIC_LINK (this_fp);
 300   if (new_fp)
 301     { new_fp = RELOC (frame, new_fp);
 302       new_sp = SCM_FRAME_LOWER_ADDRESS (this_fp) - 1;
 303       frame = scm_c_make_frame (SCM_VM_FRAME_STACK_HOLDER (frame),
 304                                 new_fp, new_sp,
 305                                 SCM_FRAME_RETURN_ADDRESS (this_fp),
 306                                 SCM_VM_FRAME_OFFSET (frame));
 307       if (SCM_PROGRAM_IS_BOOT (scm_frame_procedure (frame)))
 308         goto again;
 309       else
 310         return frame;
 311     }
 312   else
 313     return SCM_BOOL_F;
 314 }
 315 #undef FUNC_NAME
 316
 317 \f
 318 void
 319 scm_init_frames (void)
 320 {
 321 #ifndef SCM_MAGIC_SNARFER
 322 #include "libguile/frames.x"
 323 #endif
 324 }
 325
 326 /*
 327   Local Variables:
 328   c-file-style: "gnu"
 329   End:
 330 */