libguile/frames.c

   1 /* Copyright (C) 2001, 2009, 2010 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
  28 \f
  29 #define RELOC(frame, val) (val + SCM_VM_FRAME_OFFSET (frame))
  30
  31 SCM
  32 scm_c_make_frame (SCM stack_holder, SCM *fp, SCM *sp,
  33                   scm_t_uint8 *ip, scm_t_ptrdiff offset)
  34 {
  35   struct scm_frame *p = scm_gc_malloc (sizeof (struct scm_frame),
  36                                        "vmframe");
  37   p->stack_holder = stack_holder;
  38   p->fp = fp;
  39   p->sp = sp;
  40   p->ip = ip;
  41   p->offset = offset;
  42   return scm_cell (scm_tc7_frame, (scm_t_bits)p);
  43 }
  44
  45 void
  46 scm_i_frame_print (SCM frame, SCM port, scm_print_state *pstate)
  47 {
  48   scm_puts ("#<frame ", port);
  49   scm_uintprint (SCM_UNPACK (frame), 16, port);
  50   scm_putc (' ', port);
  51   scm_write (scm_frame_procedure (frame), port);
  52   /* don't write args, they can get us into trouble. */
  53   scm_puts (">", port);
  54 }
  55
  56 \f
  57 /* Scheme interface */
  58
  59 SCM_DEFINE (scm_frame_p, "frame?", 1, 0, 0,
  60             (SCM obj),
  61             "")
  62 #define FUNC_NAME s_scm_frame_p
  63 {
  64   return scm_from_bool (SCM_VM_FRAME_P (obj));
  65 }
  66 #undef FUNC_NAME
  67
  68 SCM_DEFINE (scm_frame_procedure, "frame-procedure", 1, 0, 0,
  69             (SCM frame),
  70             "")
  71 #define FUNC_NAME s_scm_frame_procedure
  72 {
  73   SCM_VALIDATE_VM_FRAME (1, frame);
  74   return SCM_FRAME_PROGRAM (SCM_VM_FRAME_FP (frame));
  75 }
  76 #undef FUNC_NAME
  77
  78 SCM_DEFINE (scm_frame_arguments, "frame-arguments", 1, 0, 0,
  79             (SCM frame),
  80             "")
  81 #define FUNC_NAME s_scm_frame_arguments
  82 {
  83   static SCM var = SCM_BOOL_F;
  84
  85   SCM_VALIDATE_VM_FRAME (1, frame);
  86
  87   if (scm_is_false (var))
  88     var = scm_c_module_lookup (scm_c_resolve_module ("system vm frame"),
  89                                "frame-arguments");
  90
  91   return scm_call_1 (SCM_VARIABLE_REF (var), frame);
  92 }
  93 #undef FUNC_NAME
  94
  95 SCM
  96 scm_frame_source (SCM frame)
  97 {
  98   static SCM var = SCM_BOOL_F;
  99
 100   if (scm_is_false (var))
 101     var = scm_c_module_lookup (scm_c_resolve_module ("system vm frame"),
 102                                "frame-source");
 103
 104   return scm_call_1 (SCM_VARIABLE_REF (var), frame);
 105 }
 106
 107 /* The number of locals would be a simple thing to compute, if it weren't for
 108    the presence of not-yet-active frames on the stack. So we have a cheap
 109    heuristic to detect not-yet-active frames, and skip over them. Perhaps we
 110    should represent them more usefully.
 111 */
 112 SCM_DEFINE (scm_frame_num_locals, "frame-num-locals", 1, 0, 0,
 113             (SCM frame),
 114             "")
 115 #define FUNC_NAME s_scm_frame_num_locals
 116 {
 117   SCM *sp, *p;
 118   unsigned int n = 0;
 119
 120   SCM_VALIDATE_VM_FRAME (1, frame);
 121
 122   sp = SCM_VM_FRAME_SP (frame);
 123   p = SCM_FRAME_STACK_ADDRESS (SCM_VM_FRAME_FP (frame));
 124   while (p <= sp)
 125     {
 126       if (p + 1 < sp && p[1] == (SCM)0)
 127         /* skip over not-yet-active frame */
 128         p += 3;
 129       else
 130         {
 131           p++;
 132           n++;
 133         }
 134     }
 135   return scm_from_uint (n);
 136 }
 137 #undef FUNC_NAME
 138
 139 /* Need same not-yet-active frame logic here as in frame-num-locals */
 140 SCM_DEFINE (scm_frame_local_ref, "frame-local-ref", 2, 0, 0,
 141             (SCM frame, SCM index),
 142             "")
 143 #define FUNC_NAME s_scm_frame_local_ref
 144 {
 145   SCM *sp, *p;
 146   unsigned int n = 0;
 147   unsigned int i;
 148
 149   SCM_VALIDATE_VM_FRAME (1, frame);
 150   SCM_VALIDATE_UINT_COPY (2, index, i);
 151
 152   sp = SCM_VM_FRAME_SP (frame);
 153   p = SCM_FRAME_STACK_ADDRESS (SCM_VM_FRAME_FP (frame));
 154   while (p <= sp)
 155     {
 156       if (p + 1 < sp && p[1] == (SCM)0)
 157         /* skip over not-yet-active frame */
 158         p += 3;
 159       else if (n == i)
 160         return *p;
 161       else
 162         {
 163           p++;
 164           n++;
 165         }
 166     }
 167   SCM_OUT_OF_RANGE (SCM_ARG2, index);
 168 }
 169 #undef FUNC_NAME
 170
 171 /* Need same not-yet-active frame logic here as in frame-num-locals */
 172 SCM_DEFINE (scm_frame_local_set_x, "frame-local-set!", 3, 0, 0,
 173             (SCM frame, SCM index, SCM val),
 174             "")
 175 #define FUNC_NAME s_scm_frame_local_set_x
 176 {
 177   SCM *sp, *p;
 178   unsigned int n = 0;
 179   unsigned int i;
 180
 181   SCM_VALIDATE_VM_FRAME (1, frame);
 182   SCM_VALIDATE_UINT_COPY (2, index, i);
 183
 184   sp = SCM_VM_FRAME_SP (frame);
 185   p = SCM_FRAME_STACK_ADDRESS (SCM_VM_FRAME_FP (frame));
 186   while (p <= sp)
 187     {
 188       if (p + 1 < sp && p[1] == (SCM)0)
 189         /* skip over not-yet-active frame */
 190         p += 3;
 191       else if (n == i)
 192         {
 193           *p = val;
 194           return SCM_UNSPECIFIED;
 195         }
 196       else
 197         {
 198           p++;
 199           n++;
 200         }
 201     }
 202   SCM_OUT_OF_RANGE (SCM_ARG2, index);
 203 }
 204 #undef FUNC_NAME
 205
 206 SCM_DEFINE (scm_frame_address, "frame-address", 1, 0, 0,
 207             (SCM frame),
 208             "Return the frame pointer for @var{frame}.")
 209 #define FUNC_NAME s_scm_frame_address
 210 {
 211   SCM_VALIDATE_VM_FRAME (1, frame);
 212   return scm_from_ulong ((unsigned long) SCM_VM_FRAME_FP (frame));
 213 }
 214 #undef FUNC_NAME
 215
 216 SCM_DEFINE (scm_frame_instruction_pointer, "frame-instruction-pointer", 1, 0, 0,
 217             (SCM frame),
 218             "")
 219 #define FUNC_NAME s_scm_frame_instruction_pointer
 220 {
 221   const struct scm_objcode *c_objcode;
 222
 223   SCM_VALIDATE_VM_FRAME (1, frame);
 224
 225   c_objcode = SCM_PROGRAM_DATA (scm_frame_procedure (frame));
 226   return scm_from_ulong ((unsigned long)
 227                          (SCM_VM_FRAME_IP (frame)
 228                           - SCM_C_OBJCODE_BASE (c_objcode)));
 229 }
 230 #undef FUNC_NAME
 231
 232 SCM_DEFINE (scm_frame_return_address, "frame-return-address", 1, 0, 0,
 233             (SCM frame),
 234             "")
 235 #define FUNC_NAME s_scm_frame_return_address
 236 {
 237   SCM_VALIDATE_VM_FRAME (1, frame);
 238   return scm_from_ulong ((unsigned long)
 239                          (SCM_FRAME_RETURN_ADDRESS
 240                           (SCM_VM_FRAME_FP (frame))));
 241 }
 242 #undef FUNC_NAME
 243
 244 SCM_DEFINE (scm_frame_mv_return_address, "frame-mv-return-address", 1, 0, 0,
 245             (SCM frame),
 246             "")
 247 #define FUNC_NAME s_scm_frame_mv_return_address
 248 {
 249   SCM_VALIDATE_VM_FRAME (1, frame);
 250   return scm_from_ulong ((unsigned long)
 251                          (SCM_FRAME_MV_RETURN_ADDRESS
 252                           (SCM_VM_FRAME_FP (frame))));
 253 }
 254 #undef FUNC_NAME
 255
 256 SCM_DEFINE (scm_frame_dynamic_link, "frame-dynamic-link", 1, 0, 0,
 257             (SCM frame),
 258             "")
 259 #define FUNC_NAME s_scm_frame_dynamic_link
 260 {
 261   SCM_VALIDATE_VM_FRAME (1, frame);
 262   /* fixme: munge fp if holder is a continuation */
 263   return scm_from_ulong
 264     ((unsigned long)
 265      RELOC (frame,
 266             SCM_FRAME_DYNAMIC_LINK (SCM_VM_FRAME_FP (frame))));
 267 }
 268 #undef FUNC_NAME
 269
 270 SCM_DEFINE (scm_frame_previous, "frame-previous", 1, 0, 0,
 271             (SCM frame),
 272             "")
 273 #define FUNC_NAME s_scm_frame_previous
 274 {
 275   SCM *this_fp, *new_fp, *new_sp;
 276
 277   SCM_VALIDATE_VM_FRAME (1, frame);
 278
 279  again:
 280   this_fp = SCM_VM_FRAME_FP (frame);
 281   new_fp = SCM_FRAME_DYNAMIC_LINK (this_fp);
 282   if (new_fp)
 283     { new_fp = RELOC (frame, new_fp);
 284       new_sp = SCM_FRAME_LOWER_ADDRESS (this_fp) - 1;
 285       frame = scm_c_make_frame (SCM_VM_FRAME_STACK_HOLDER (frame),
 286                                 new_fp, new_sp,
 287                                 SCM_FRAME_RETURN_ADDRESS (this_fp),
 288                                 SCM_VM_FRAME_OFFSET (frame));
 289       if (SCM_PROGRAM_IS_BOOT (scm_frame_procedure (frame)))
 290         goto again;
 291       else
 292         return frame;
 293     }
 294   else
 295     return SCM_BOOL_F;
 296 }
 297 #undef FUNC_NAME
 298
 299 \f
 300 void
 301 scm_init_frames (void)
 302 {
 303 #ifndef SCM_MAGIC_SNARFER
 304 #include "libguile/frames.x"
 305 #endif
 306 }
 307
 308 /*
 309   Local Variables:
 310   c-file-style: "gnu"
 311   End:
 312 */