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 ("#<frame ", port);
  56   scm_uintprint (SCM_UNPACK (frame), 16, port);
  57   scm_putc (' ', port);
  58   scm_write (scm_frame_procedure (frame), port);
  59   /* don't write args, they can get us into trouble. */
  60   scm_puts (">", 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 static SCM frame_arguments_var;
  86
  87 static void
  88 init_frame_arguments_var (void)
  89 {
  90   frame_arguments_var
  91     = scm_c_private_lookup ("system vm frame", "frame-arguments");
  92 }
  93
  94 SCM_DEFINE (scm_frame_arguments, "frame-arguments", 1, 0, 0,
  95             (SCM frame),
  96             "")
  97 #define FUNC_NAME s_scm_frame_arguments
  98 {
  99   static scm_i_pthread_once_t once = SCM_I_PTHREAD_ONCE_INIT;
 100   scm_i_pthread_once (&once, init_frame_arguments_var);
 101
 102   SCM_VALIDATE_VM_FRAME (1, frame);
 103
 104   return scm_call_1 (scm_variable_ref (frame_arguments_var), frame);
 105 }
 106 #undef FUNC_NAME
 107
 108 SCM_DEFINE (scm_frame_source, "frame-source", 1, 0, 0,
 109             (SCM frame),
 110             "")
 111 #define FUNC_NAME s_scm_frame_source
 112 {
 113   SCM proc;
 114
 115   SCM_VALIDATE_VM_FRAME (1, frame);
 116
 117   proc = scm_frame_procedure (frame);
 118
 119   if (SCM_PROGRAM_P (proc))
 120     return scm_program_source (scm_frame_procedure (frame),
 121                                scm_frame_instruction_pointer (frame),
 122                                SCM_UNDEFINED);
 123
 124   return SCM_BOOL_F;
 125 }
 126 #undef FUNC_NAME
 127
 128 /* The number of locals would be a simple thing to compute, if it weren't for
 129    the presence of not-yet-active frames on the stack. So we have a cheap
 130    heuristic to detect not-yet-active frames, and skip over them. Perhaps we
 131    should represent them more usefully.
 132 */
 133 SCM_DEFINE (scm_frame_num_locals, "frame-num-locals", 1, 0, 0,
 134             (SCM frame),
 135             "")
 136 #define FUNC_NAME s_scm_frame_num_locals
 137 {
 138   SCM *sp, *p;
 139   unsigned int n = 0;
 140
 141   SCM_VALIDATE_VM_FRAME (1, frame);
 142
 143   sp = SCM_VM_FRAME_SP (frame);
 144   p = SCM_FRAME_STACK_ADDRESS (SCM_VM_FRAME_FP (frame));
 145   while (p <= sp)
 146     {
 147       if (SCM_UNPACK (p[0]) == 0)
 148         /* skip over not-yet-active frame */
 149         p += 3;
 150       else
 151         {
 152           p++;
 153           n++;
 154         }
 155     }
 156   return scm_from_uint (n);
 157 }
 158 #undef FUNC_NAME
 159
 160 /* Need same not-yet-active frame logic here as in frame-num-locals */
 161 SCM_DEFINE (scm_frame_local_ref, "frame-local-ref", 2, 0, 0,
 162             (SCM frame, SCM index),
 163             "")
 164 #define FUNC_NAME s_scm_frame_local_ref
 165 {
 166   SCM *sp, *p;
 167   unsigned int n = 0;
 168   unsigned int i;
 169
 170   SCM_VALIDATE_VM_FRAME (1, frame);
 171   SCM_VALIDATE_UINT_COPY (2, index, i);
 172
 173   sp = SCM_VM_FRAME_SP (frame);
 174   p = SCM_FRAME_STACK_ADDRESS (SCM_VM_FRAME_FP (frame));
 175   while (p <= sp)
 176     {
 177       if (SCM_UNPACK (p[0]) == 0)
 178         /* skip over not-yet-active frame */
 179         p += 3;
 180       else if (n == i)
 181         return *p;
 182       else
 183         {
 184           p++;
 185           n++;
 186         }
 187     }
 188   SCM_OUT_OF_RANGE (SCM_ARG2, index);
 189 }
 190 #undef FUNC_NAME
 191
 192 /* Need same not-yet-active frame logic here as in frame-num-locals */
 193 SCM_DEFINE (scm_frame_local_set_x, "frame-local-set!", 3, 0, 0,
 194             (SCM frame, SCM index, SCM val),
 195             "")
 196 #define FUNC_NAME s_scm_frame_local_set_x
 197 {
 198   SCM *sp, *p;
 199   unsigned int n = 0;
 200   unsigned int i;
 201
 202   SCM_VALIDATE_VM_FRAME (1, frame);
 203   SCM_VALIDATE_UINT_COPY (2, index, i);
 204
 205   sp = SCM_VM_FRAME_SP (frame);
 206   p = SCM_FRAME_STACK_ADDRESS (SCM_VM_FRAME_FP (frame));
 207   while (p <= sp)
 208     {
 209       if (SCM_UNPACK (p[0]) == 0)
 210         /* skip over not-yet-active frame */
 211         p += 3;
 212       else if (n == i)
 213         {
 214           *p = val;
 215           return SCM_UNSPECIFIED;
 216         }
 217       else
 218         {
 219           p++;
 220           n++;
 221         }
 222     }
 223   SCM_OUT_OF_RANGE (SCM_ARG2, index);
 224 }
 225 #undef FUNC_NAME
 226
 227 SCM_DEFINE (scm_frame_address, "frame-address", 1, 0, 0,
 228             (SCM frame),
 229             "Return the frame pointer for @var{frame}.")
 230 #define FUNC_NAME s_scm_frame_address
 231 {
 232   SCM_VALIDATE_VM_FRAME (1, frame);
 233   return scm_from_unsigned_integer ((scm_t_bits) SCM_VM_FRAME_FP (frame));
 234 }
 235 #undef FUNC_NAME
 236
 237 SCM_DEFINE (scm_frame_stack_pointer, "frame-stack-pointer", 1, 0, 0,
 238             (SCM frame),
 239             "")
 240 #define FUNC_NAME s_scm_frame_stack_pointer
 241 {
 242   SCM_VALIDATE_VM_FRAME (1, frame);
 243
 244   return scm_from_unsigned_integer ((scm_t_bits) SCM_VM_FRAME_SP (frame));
 245 }
 246 #undef FUNC_NAME
 247
 248 SCM_DEFINE (scm_frame_instruction_pointer, "frame-instruction-pointer", 1, 0, 0,
 249             (SCM frame),
 250             "")
 251 #define FUNC_NAME s_scm_frame_instruction_pointer
 252 {
 253   SCM program;
 254   const struct scm_objcode *c_objcode;
 255
 256   SCM_VALIDATE_VM_FRAME (1, frame);
 257   program = scm_frame_procedure (frame);
 258
 259   if (!SCM_PROGRAM_P (program))
 260     return SCM_INUM0;
 261
 262   c_objcode = SCM_PROGRAM_DATA (program);
 263   return scm_from_unsigned_integer ((SCM_VM_FRAME_IP (frame)
 264                                      - SCM_C_OBJCODE_BASE (c_objcode)));
 265 }
 266 #undef FUNC_NAME
 267
 268 SCM_DEFINE (scm_frame_return_address, "frame-return-address", 1, 0, 0,
 269             (SCM frame),
 270             "")
 271 #define FUNC_NAME s_scm_frame_return_address
 272 {
 273   SCM_VALIDATE_VM_FRAME (1, frame);
 274   return scm_from_unsigned_integer ((scm_t_bits)
 275                                     (SCM_FRAME_RETURN_ADDRESS
 276                                      (SCM_VM_FRAME_FP (frame))));
 277 }
 278 #undef FUNC_NAME
 279
 280 SCM_DEFINE (scm_frame_mv_return_address, "frame-mv-return-address", 1, 0, 0,
 281             (SCM frame),
 282             "")
 283 #define FUNC_NAME s_scm_frame_mv_return_address
 284 {
 285   SCM_VALIDATE_VM_FRAME (1, frame);
 286   return scm_from_unsigned_integer ((scm_t_bits)
 287                                     (SCM_FRAME_MV_RETURN_ADDRESS
 288                                      (SCM_VM_FRAME_FP (frame))));
 289 }
 290 #undef FUNC_NAME
 291
 292 SCM_DEFINE (scm_frame_dynamic_link, "frame-dynamic-link", 1, 0, 0,
 293             (SCM frame),
 294             "")
 295 #define FUNC_NAME s_scm_frame_dynamic_link
 296 {
 297   SCM_VALIDATE_VM_FRAME (1, frame);
 298   /* fixme: munge fp if holder is a continuation */
 299   return scm_from_ulong
 300     ((unsigned long)
 301      RELOC (frame,
 302             SCM_FRAME_DYNAMIC_LINK (SCM_VM_FRAME_FP (frame))));
 303 }
 304 #undef FUNC_NAME
 305
 306 SCM_DEFINE (scm_frame_previous, "frame-previous", 1, 0, 0,
 307             (SCM frame),
 308             "")
 309 #define FUNC_NAME s_scm_frame_previous
 310 {
 311   SCM *this_fp, *new_fp, *new_sp;
 312   SCM proc;
 313
 314   SCM_VALIDATE_VM_FRAME (1, frame);
 315
 316  again:
 317   this_fp = SCM_VM_FRAME_FP (frame);
 318   new_fp = SCM_FRAME_DYNAMIC_LINK (this_fp);
 319   if (new_fp)
 320     {
 321       new_fp = RELOC (frame, new_fp);
 322       new_sp = SCM_FRAME_LOWER_ADDRESS (this_fp) - 1;
 323       frame = scm_c_make_frame (SCM_VM_FRAME_STACK_HOLDER (frame),
 324                                 new_fp, new_sp,
 325                                 SCM_FRAME_RETURN_ADDRESS (this_fp),
 326                                 SCM_VM_FRAME_OFFSET (frame));
 327       proc = scm_frame_procedure (frame);
 328
 329       if (SCM_PROGRAM_P (proc) && SCM_PROGRAM_IS_BOOT (proc))
 330         goto again;
 331       else
 332         return frame;
 333     }
 334   else
 335     return SCM_BOOL_F;
 336 }
 337 #undef FUNC_NAME
 338
 339 \f
 340 void
 341 scm_init_frames (void)
 342 {
 343 #ifndef SCM_MAGIC_SNARFER
 344 #include "libguile/frames.x"
 345 #endif
 346 }
 347
 348 /*
 349   Local Variables:
 350   c-file-style: "gnu"
 351   End:
 352 */