1 /* A stack holds a frame chain
2 * Copyright (C) 1996,1997,2000,2001, 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public License
6 * as published by the Free Software Foundation; either version 3 of
7 * the License, or (at your option) any later version.
9 * This library is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with this library; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
26 #include "libguile/_scm.h"
27 #include "libguile/control.h"
28 #include "libguile/eval.h"
29 #include "libguile/debug.h"
30 #include "libguile/continuations.h"
31 #include "libguile/struct.h"
32 #include "libguile/macros.h"
33 #include "libguile/procprop.h"
34 #include "libguile/modules.h"
35 #include "libguile/root.h"
36 #include "libguile/strings.h"
37 #include "libguile/vm.h" /* to capture vm stacks */
38 #include "libguile/frames.h" /* vm frames */
40 #include "libguile/validate.h"
41 #include "libguile/stacks.h"
42 #include "libguile/private-options.h"
45 static SCM scm_sys_stacks
;
50 * The stack is represented as a struct that holds a frame. The frame itself is
51 * linked to the next frame, or #f.
65 /* Count number of debug info frames on a stack, beginning with FRAME.
68 stack_depth (SCM frame
)
71 /* count frames, skipping boot frames */
72 for (; scm_is_true (frame
); frame
= scm_frame_previous (frame
))
77 /* Narrow STACK by cutting away stackframes (mutatingly).
79 * Inner frames (most recent) are cut by advancing the frames pointer.
80 * Outer frames are cut by decreasing the recorded length.
82 * Cut maximally INNER inner frames and OUTER outer frames using
83 * the keys INNER_KEY and OUTER_KEY.
85 * Frames are cut away starting at the end points and moving towards
86 * the center of the stack. The key is normally compared to the
87 * operator in application frames. Frames up to and including the key
90 * If INNER_KEY is #t a different scheme is used for inner frames:
92 * Frames up to but excluding the first source frame originating from
93 * a user module are cut, except for possible application frames
94 * between the user frame and the last system frame previously
102 for (winds
= scm_i_dynwinds (); scm_is_pair (winds
); winds
= scm_cdr (winds
))
104 SCM elt
= scm_car (winds
);
105 if (SCM_PROMPT_P (elt
) && scm_is_eq (SCM_PROMPT_TAG (elt
), key
))
108 scm_misc_error ("make-stack", "Prompt tag not found while narrowing stack",
110 return SCM_BOOL_F
; /* not reached */
114 narrow_stack (SCM stack
, long inner
, SCM inner_key
, long outer
, SCM outer_key
)
116 unsigned long int len
;
119 len
= SCM_STACK_LENGTH (stack
);
120 frame
= SCM_STACK_FRAME (stack
);
122 /* Cut inner part. */
123 if (scm_is_true (scm_procedure_p (inner_key
)))
125 /* Cut until the given procedure is seen. */
126 for (; inner
&& len
; --inner
)
128 SCM proc
= scm_frame_procedure (frame
);
130 frame
= scm_frame_previous (frame
);
131 if (scm_is_eq (proc
, inner_key
))
135 else if (scm_is_symbol (inner_key
))
137 /* Cut until the given prompt tag is seen. FIXME, assumes prompt tags are
139 SCM prompt
= find_prompt (inner_key
);
140 for (; len
; len
--, frame
= scm_frame_previous (frame
))
141 if (SCM_PROMPT_REGISTERS (prompt
)->fp
142 == SCM_VM_FRAME_FP (frame
) - SCM_VM_FRAME_OFFSET (frame
))
147 /* Cut specified number of frames. */
148 for (; inner
&& len
; --inner
)
151 frame
= scm_frame_previous (frame
);
155 SCM_SET_STACK_LENGTH (stack
, len
);
156 SCM_SET_STACK_FRAME (stack
, frame
);
158 /* Cut outer part. */
159 if (scm_is_true (scm_procedure_p (outer_key
)))
161 /* Cut until the given procedure is seen. */
162 for (; outer
&& len
; --outer
)
164 frame
= scm_stack_ref (stack
, scm_from_long (len
- 1));
166 if (scm_is_eq (scm_frame_procedure (frame
), outer_key
))
170 else if (scm_is_symbol (outer_key
))
172 /* Cut until the given prompt tag is seen. FIXME, assumes prompt tags are
174 SCM prompt
= find_prompt (outer_key
);
177 frame
= scm_stack_ref (stack
, scm_from_long (len
- 1));
179 if (SCM_PROMPT_REGISTERS (prompt
)->fp
180 == SCM_VM_FRAME_FP (frame
) - SCM_VM_FRAME_OFFSET (frame
))
186 /* Cut specified number of frames. */
193 SCM_SET_STACK_LENGTH (stack
, len
);
203 SCM_DEFINE (scm_stack_p
, "stack?", 1, 0, 0,
205 "Return @code{#t} if @var{obj} is a calling stack.")
206 #define FUNC_NAME s_scm_stack_p
208 return scm_from_bool(SCM_STACKP (obj
));
212 SCM_DEFINE (scm_make_stack
, "make-stack", 1, 0, 1,
214 "Create a new stack. If @var{obj} is @code{#t}, the current\n"
215 "evaluation stack is used for creating the stack frames,\n"
216 "otherwise the frames are taken from @var{obj} (which must be\n"
217 "a continuation or a frame object).\n"
219 "@var{args} should be a list containing any combination of\n"
220 "integer, procedure, prompt tag and @code{#t} values.\n"
222 "These values specify various ways of cutting away uninteresting\n"
223 "stack frames from the top and bottom of the stack that\n"
224 "@code{make-stack} returns. They come in pairs like this:\n"
225 "@code{(@var{inner_cut_1} @var{outer_cut_1} @var{inner_cut_2}\n"
226 "@var{outer_cut_2} @dots{})}.\n"
228 "Each @var{inner_cut_i} can be @code{#t}, an integer, a prompt\n"
229 "tag, or a procedure. @code{#t} means to cut away all frames up\n"
230 "to but excluding the first user module frame. An integer means\n"
231 "to cut away exactly that number of frames. A prompt tag means\n"
232 "to cut away all frames that are inside a prompt with the given\n"
233 "tag. A procedure means to cut away all frames up to but\n"
234 "excluding the application frame whose procedure matches the\n"
237 "Each @var{outer_cut_i} can be an integer, a prompt tag, or a\n"
238 "procedure. An integer means to cut away that number of frames.\n"
239 "A prompt tag means to cut away all frames that are outside a\n"
240 "prompt with the given tag. A procedure means to cut away\n"
241 "frames down to but excluding the application frame whose\n"
242 "procedure matches the specified one.\n"
244 "If the @var{outer_cut_i} of the last pair is missing, it is\n"
246 #define FUNC_NAME s_scm_make_stack
251 SCM inner_cut
, outer_cut
;
253 /* Extract a pointer to the innermost frame of whatever object
254 scm_make_stack was given. */
255 if (scm_is_eq (obj
, SCM_BOOL_T
))
258 struct scm_vm_cont
*c
;
260 cont
= scm_i_vm_capture_continuation (scm_the_vm ());
261 c
= SCM_VM_CONT_DATA (cont
);
263 frame
= scm_c_make_frame (cont
, c
->fp
+ c
->reloc
,
264 c
->sp
+ c
->reloc
, c
->ra
,
267 else if (SCM_VM_FRAME_P (obj
))
269 else if (SCM_CONTINUATIONP (obj
))
270 /* FIXME: Narrowing to prompt tags should narrow with respect to the prompts
271 that were in place when the continuation was captured. */
272 frame
= scm_i_continuation_to_frame (obj
);
275 SCM_WRONG_TYPE_ARG (SCM_ARG1
, obj
);
279 /* FIXME: is this even possible? */
280 if (scm_is_true (frame
)
281 && SCM_PROGRAM_IS_BOOT (scm_frame_procedure (frame
)))
282 frame
= scm_frame_previous (frame
);
284 if (scm_is_false (frame
))
287 /* Count number of frames. Also get stack id tag and check whether
288 there are more stackframes than we want to record
289 (SCM_BACKTRACE_MAXDEPTH). */
290 n
= stack_depth (frame
);
292 /* Make the stack object. */
293 stack
= scm_make_struct (scm_stack_type
, SCM_INUM0
, SCM_EOL
);
294 SCM_SET_STACK_LENGTH (stack
, n
);
295 SCM_SET_STACK_ID (stack
, scm_stack_id (obj
));
296 SCM_SET_STACK_FRAME (stack
, frame
);
298 /* Narrow the stack according to the arguments given to scm_make_stack. */
299 SCM_VALIDATE_REST_ARGUMENT (args
);
300 while (n
> 0 && !scm_is_null (args
))
302 inner_cut
= SCM_CAR (args
);
303 args
= SCM_CDR (args
);
304 if (scm_is_null (args
))
306 outer_cut
= SCM_INUM0
;
310 outer_cut
= SCM_CAR (args
);
311 args
= SCM_CDR (args
);
315 scm_is_integer (inner_cut
) ? scm_to_int (inner_cut
) : n
,
316 scm_is_integer (inner_cut
) ? SCM_BOOL_T
: inner_cut
,
317 scm_is_integer (outer_cut
) ? scm_to_int (outer_cut
) : n
,
318 scm_is_integer (outer_cut
) ? SCM_BOOL_T
: outer_cut
);
320 n
= SCM_STACK_LENGTH (stack
);
330 SCM_DEFINE (scm_stack_id
, "stack-id", 1, 0, 0,
332 "Return the identifier given to @var{stack} by @code{start-stack}.")
333 #define FUNC_NAME s_scm_stack_id
335 if (scm_is_eq (stack
, SCM_BOOL_T
)
336 /* FIXME: frame case assumes frame still live on the stack, and no
337 intervening start-stack. Hmm... */
338 || SCM_VM_FRAME_P (stack
))
340 /* Fetch most recent start-stack tag. */
341 SCM stacks
= scm_fluid_ref (scm_sys_stacks
);
342 return scm_is_pair (stacks
) ? scm_caar (stacks
) : SCM_BOOL_F
;
344 else if (SCM_CONTINUATIONP (stack
))
345 /* FIXME: implement me */
349 SCM_WRONG_TYPE_ARG (SCM_ARG1
, stack
);
355 SCM_DEFINE (scm_stack_ref
, "stack-ref", 2, 0, 0,
356 (SCM stack
, SCM index
),
357 "Return the @var{index}'th frame from @var{stack}.")
358 #define FUNC_NAME s_scm_stack_ref
360 unsigned long int c_index
;
363 SCM_VALIDATE_STACK (1, stack
);
364 c_index
= scm_to_unsigned_integer (index
, 0, SCM_STACK_LENGTH(stack
)-1);
365 frame
= SCM_STACK_FRAME (stack
);
367 frame
= scm_frame_previous (frame
);
372 SCM_DEFINE (scm_stack_length
, "stack-length", 1, 0, 0,
374 "Return the length of @var{stack}.")
375 #define FUNC_NAME s_scm_stack_length
377 SCM_VALIDATE_STACK (1, stack
);
378 return scm_from_long (SCM_STACK_LENGTH (stack
));
387 scm_sys_stacks
= scm_make_fluid ();
388 scm_c_define ("%stacks", scm_sys_stacks
);
390 scm_stack_type
= scm_make_vtable (scm_from_locale_string (SCM_STACK_LAYOUT
),
392 scm_set_struct_vtable_name_x (scm_stack_type
,
393 scm_from_latin1_symbol ("stack"));
394 #include "libguile/stacks.x"