libguile/frames.h

   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 #ifndef _SCM_FRAMES_H_
  20 #define _SCM_FRAMES_H_
  21
  22 #include <libguile.h>
  23 #include "programs.h"
  24
  25 \f
  26 /*
  27  * VM frames
  28  */
  29
  30 /*
  31  * It's a little confusing, but there are two representations of frames in this
  32  * file: frame pointers and Scheme objects wrapping those frame pointers. The
  33  * former uses the SCM_FRAME_... macro prefix, the latter SCM_VM_FRAME_..
  34  * prefix.
  35  *
  36  * The confusing thing is that only Scheme frame objects have functions that use
  37  * them, and they use the scm_frame_.. prefix. Hysterical raisins.
  38  */
  39
  40 /* VM Frame Layout
  41    ---------------
  42
  43    | ...              |
  44    | Intermed. val. 0 | <- fp + nargs + nlocs
  45    +------------------+
  46    | Local variable 1 |
  47    | Local variable 0 | <- fp + nargs
  48    | Argument 1       |
  49    | Argument 0       | <- fp = SCM_FRAME_STACK_ADDRESS (fp)
  50    | Program          | <- fp - 1
  51    +==================+
  52    | Return address   | <- SCM_FRAME_UPPER_ADDRESS (fp)
  53    | MV return address|
  54    | Dynamic link     | <- fp - 4 = SCM_FRAME_DATA_ADDRESS (fp) = SCM_FRAME_LOWER_ADDRESS (fp)
  55    +==================+
  56    |                  |
  57
  58    As can be inferred from this drawing, it is assumed that
  59    `sizeof (SCM *) == sizeof (SCM)', since pointers (the `link' parts) are
  60    assumed to be as long as SCM objects.  */
  61
  62 #define SCM_FRAME_DATA_ADDRESS(fp)      (fp - 4)
  63 #define SCM_FRAME_STACK_ADDRESS(fp)     (fp)
  64 #define SCM_FRAME_UPPER_ADDRESS(fp)     (fp - 2)
  65 #define SCM_FRAME_LOWER_ADDRESS(fp)     (fp - 4)
  66
  67 #define SCM_FRAME_BYTE_CAST(x)          ((scm_t_uint8 *) SCM_UNPACK (x))
  68 #define SCM_FRAME_STACK_CAST(x)         ((SCM *) SCM_UNPACK (x))
  69
  70 #define SCM_FRAME_RETURN_ADDRESS(fp)                            \
  71   (SCM_FRAME_BYTE_CAST (SCM_FRAME_DATA_ADDRESS (fp)[2]))
  72 #define SCM_FRAME_SET_RETURN_ADDRESS(fp, ra)                    \
  73   ((SCM_FRAME_DATA_ADDRESS (fp)[2])) = (SCM)(ra);
  74 #define SCM_FRAME_MV_RETURN_ADDRESS(fp)                         \
  75   (SCM_FRAME_BYTE_CAST (SCM_FRAME_DATA_ADDRESS (fp)[1]))
  76 #define SCM_FRAME_SET_MV_RETURN_ADDRESS(fp, mvra)               \
  77   ((SCM_FRAME_DATA_ADDRESS (fp)[1])) = (SCM)(mvra);
  78 #define SCM_FRAME_DYNAMIC_LINK(fp)                              \
  79   (SCM_FRAME_STACK_CAST (SCM_FRAME_DATA_ADDRESS (fp)[0]))
  80 #define SCM_FRAME_SET_DYNAMIC_LINK(fp, dl)                      \
  81   ((SCM_FRAME_DATA_ADDRESS (fp)[0])) = (SCM)(dl);
  82 #define SCM_FRAME_VARIABLE(fp,i)        SCM_FRAME_STACK_ADDRESS (fp)[i]
  83 #define SCM_FRAME_PROGRAM(fp)           SCM_FRAME_STACK_ADDRESS (fp)[-1]
  84
  85 \f
  86 /*
  87  * Heap frames
  88  */
  89
  90 struct scm_frame
  91 {
  92   SCM stack_holder;
  93   SCM *fp;
  94   SCM *sp;
  95   scm_t_uint8 *ip;
  96   scm_t_ptrdiff offset;
  97 };
  98
  99 #define SCM_VM_FRAME_P(x)       (SCM_NIMP (x) && SCM_TYP7 (x) == scm_tc7_frame)
 100 #define SCM_VM_FRAME_DATA(x)    ((struct scm_frame*)SCM_CELL_WORD_1 (x))
 101 #define SCM_VM_FRAME_STACK_HOLDER(f)    SCM_VM_FRAME_DATA(f)->stack_holder
 102 #define SCM_VM_FRAME_FP(f)      SCM_VM_FRAME_DATA(f)->fp
 103 #define SCM_VM_FRAME_SP(f)      SCM_VM_FRAME_DATA(f)->sp
 104 #define SCM_VM_FRAME_IP(f)      SCM_VM_FRAME_DATA(f)->ip
 105 #define SCM_VM_FRAME_OFFSET(f)  SCM_VM_FRAME_DATA(f)->offset
 106 #define SCM_VALIDATE_VM_FRAME(p,x)      SCM_MAKE_VALIDATE (p, x, VM_FRAME_P)
 107
 108 SCM_API SCM scm_c_make_frame (SCM stack_holder, SCM *fp, SCM *sp,
 109                               scm_t_uint8 *ip, scm_t_ptrdiff offset);
 110 SCM_API SCM scm_frame_p (SCM obj);
 111 SCM_API SCM scm_frame_procedure (SCM frame);
 112 SCM_API SCM scm_frame_arguments (SCM frame);
 113 SCM_API SCM scm_frame_source (SCM frame);
 114 SCM_API SCM scm_frame_num_locals (SCM frame);
 115 SCM_API SCM scm_frame_local_ref (SCM frame, SCM index);
 116 SCM_API SCM scm_frame_local_set_x (SCM frame, SCM index, SCM val);
 117 SCM_API SCM scm_frame_address (SCM frame);
 118 SCM_API SCM scm_frame_instruction_pointer (SCM frame);
 119 SCM_API SCM scm_frame_return_address (SCM frame);
 120 SCM_API SCM scm_frame_mv_return_address (SCM frame);
 121 SCM_API SCM scm_frame_dynamic_link (SCM frame);
 122 SCM_API SCM scm_frame_previous (SCM frame);
 123
 124 SCM_INTERNAL void scm_i_frame_print (SCM frame, SCM port,
 125                                      scm_print_state *pstate);
 126 SCM_INTERNAL void scm_init_frames (void);
 127
 128 #endif /* _SCM_FRAMES_H_ */
 129
 130 /*
 131   Local Variables:
 132   c-file-style: "gnu"
 133   End:
 134 */