1 /* A stack holds a frame chain
2 * Copyright (C) 1996,1997,2000,2001, 2006, 2007, 2008, 2009, 2010, 2011, 2012 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
103 if (!scm_dynstack_find_prompt (&SCM_I_CURRENT_THREAD
->dynstack
, key
,
104 NULL
, &fp
, NULL
, NULL
, NULL
))
105 scm_misc_error ("make-stack", "Prompt tag not found while narrowing stack",
112 narrow_stack (SCM stack
, SCM inner_cut
, SCM outer_cut
)
114 unsigned long int len
;
117 len
= SCM_STACK_LENGTH (stack
);
118 frame
= SCM_STACK_FRAME (stack
);
120 /* Cut inner part. */
121 if (scm_is_true (scm_procedure_p (inner_cut
)))
123 /* Cut until the given procedure is seen. */
126 SCM proc
= scm_frame_procedure (frame
);
128 frame
= scm_frame_previous (frame
);
129 if (scm_is_eq (proc
, inner_cut
))
133 else if (scm_is_integer (inner_cut
))
135 /* Cut specified number of frames. */
136 long inner
= scm_to_int (inner_cut
);
138 for (; inner
&& len
; --inner
)
141 frame
= scm_frame_previous (frame
);
146 /* Cut until the given prompt tag is seen. */
147 SCM
*fp
= find_prompt (inner_cut
);
148 for (; len
; len
--, frame
= scm_frame_previous (frame
))
149 if (fp
== SCM_VM_FRAME_FP (frame
) - SCM_VM_FRAME_OFFSET (frame
))
153 SCM_SET_STACK_LENGTH (stack
, len
);
154 SCM_SET_STACK_FRAME (stack
, frame
);
156 /* Cut outer part. */
157 if (scm_is_true (scm_procedure_p (outer_cut
)))
159 /* Cut until the given procedure is seen. */
162 frame
= scm_stack_ref (stack
, scm_from_long (len
- 1));
164 if (scm_is_eq (scm_frame_procedure (frame
), outer_cut
))
168 else if (scm_is_integer (outer_cut
))
170 /* Cut specified number of frames. */
171 long outer
= scm_to_int (outer_cut
);
180 /* Cut until the given prompt tag is seen. */
181 SCM
*fp
= find_prompt (outer_cut
);
184 frame
= scm_stack_ref (stack
, scm_from_long (len
- 1));
186 if (fp
== SCM_VM_FRAME_FP (frame
) - SCM_VM_FRAME_OFFSET (frame
))
191 SCM_SET_STACK_LENGTH (stack
, len
);
201 SCM_DEFINE (scm_stack_p
, "stack?", 1, 0, 0,
203 "Return @code{#t} if @var{obj} is a calling stack.")
204 #define FUNC_NAME s_scm_stack_p
206 return scm_from_bool(SCM_STACKP (obj
));
210 SCM_DEFINE (scm_make_stack
, "make-stack", 1, 0, 1,
212 "Create a new stack. If @var{obj} is @code{#t}, the current\n"
213 "evaluation stack is used for creating the stack frames,\n"
214 "otherwise the frames are taken from @var{obj} (which must be\n"
215 "a continuation or a frame object).\n"
217 "@var{args} should be a list containing any combination of\n"
218 "integer, procedure, prompt tag and @code{#t} values.\n"
220 "These values specify various ways of cutting away uninteresting\n"
221 "stack frames from the top and bottom of the stack that\n"
222 "@code{make-stack} returns. They come in pairs like this:\n"
223 "@code{(@var{inner_cut_1} @var{outer_cut_1} @var{inner_cut_2}\n"
224 "@var{outer_cut_2} @dots{})}.\n"
226 "Each @var{inner_cut_i} can be @code{#t}, an integer, a prompt\n"
227 "tag, or a procedure. @code{#t} means to cut away all frames up\n"
228 "to but excluding the first user module frame. An integer means\n"
229 "to cut away exactly that number of frames. A prompt tag means\n"
230 "to cut away all frames that are inside a prompt with the given\n"
231 "tag. A procedure means to cut away all frames up to but\n"
232 "excluding the application frame whose procedure matches the\n"
235 "Each @var{outer_cut_i} can be an integer, a prompt tag, or a\n"
236 "procedure. An integer means to cut away that number of frames.\n"
237 "A prompt tag means to cut away all frames that are outside a\n"
238 "prompt with the given tag. A procedure means to cut away\n"
239 "frames down to but excluding the application frame whose\n"
240 "procedure matches the specified one.\n"
242 "If the @var{outer_cut_i} of the last pair is missing, it is\n"
244 #define FUNC_NAME s_scm_make_stack
249 SCM inner_cut
, outer_cut
;
251 /* Extract a pointer to the innermost frame of whatever object
252 scm_make_stack was given. */
253 if (scm_is_eq (obj
, SCM_BOOL_T
))
256 struct scm_vm_cont
*c
;
258 cont
= scm_i_capture_current_stack ();
259 c
= SCM_VM_CONT_DATA (cont
);
261 frame
= scm_c_make_frame (cont
, c
->fp
+ c
->reloc
,
262 c
->sp
+ c
->reloc
, c
->ra
,
265 else if (SCM_VM_FRAME_P (obj
))
267 else if (SCM_CONTINUATIONP (obj
))
268 /* FIXME: Narrowing to prompt tags should narrow with respect to the prompts
269 that were in place when the continuation was captured. */
270 frame
= scm_i_continuation_to_frame (obj
);
273 SCM_WRONG_TYPE_ARG (SCM_ARG1
, obj
);
277 /* FIXME: is this even possible? */
278 if (scm_is_true (frame
)
279 && SCM_PROGRAM_P (scm_frame_procedure (frame
))
280 && SCM_PROGRAM_IS_BOOT (scm_frame_procedure (frame
)))
281 frame
= scm_frame_previous (frame
);
283 if (scm_is_false (frame
))
286 /* Count number of frames. Also get stack id tag and check whether
287 there are more stackframes than we want to record
288 (SCM_BACKTRACE_MAXDEPTH). */
289 n
= stack_depth (frame
);
291 /* Make the stack object. */
292 stack
= scm_make_struct (scm_stack_type
, SCM_INUM0
, SCM_EOL
);
293 SCM_SET_STACK_LENGTH (stack
, n
);
294 SCM_SET_STACK_ID (stack
, scm_stack_id (obj
));
295 SCM_SET_STACK_FRAME (stack
, frame
);
297 /* Narrow the stack according to the arguments given to scm_make_stack. */
298 SCM_VALIDATE_REST_ARGUMENT (args
);
299 while (n
> 0 && !scm_is_null (args
))
301 inner_cut
= SCM_CAR (args
);
302 args
= SCM_CDR (args
);
303 if (scm_is_null (args
))
305 outer_cut
= SCM_INUM0
;
309 outer_cut
= SCM_CAR (args
);
310 args
= SCM_CDR (args
);
317 n
= SCM_STACK_LENGTH (stack
);
327 SCM_DEFINE (scm_stack_id
, "stack-id", 1, 0, 0,
329 "Return the identifier given to @var{stack} by @code{start-stack}.")
330 #define FUNC_NAME s_scm_stack_id
332 if (scm_is_eq (stack
, SCM_BOOL_T
)
333 /* FIXME: frame case assumes frame still live on the stack, and no
334 intervening start-stack. Hmm... */
335 || SCM_VM_FRAME_P (stack
))
337 /* Fetch most recent start-stack tag. */
338 SCM stacks
= scm_fluid_ref (scm_sys_stacks
);
339 return scm_is_pair (stacks
) ? scm_caar (stacks
) : SCM_BOOL_F
;
341 else if (SCM_CONTINUATIONP (stack
))
342 /* FIXME: implement me */
346 SCM_WRONG_TYPE_ARG (SCM_ARG1
, stack
);
352 SCM_DEFINE (scm_stack_ref
, "stack-ref", 2, 0, 0,
353 (SCM stack
, SCM index
),
354 "Return the @var{index}'th frame from @var{stack}.")
355 #define FUNC_NAME s_scm_stack_ref
357 unsigned long int c_index
;
360 SCM_VALIDATE_STACK (1, stack
);
361 c_index
= scm_to_unsigned_integer (index
, 0, SCM_STACK_LENGTH(stack
)-1);
362 frame
= SCM_STACK_FRAME (stack
);
364 frame
= scm_frame_previous (frame
);
369 SCM_DEFINE (scm_stack_length
, "stack-length", 1, 0, 0,
371 "Return the length of @var{stack}.")
372 #define FUNC_NAME s_scm_stack_length
374 SCM_VALIDATE_STACK (1, stack
);
375 return scm_from_long (SCM_STACK_LENGTH (stack
));
384 scm_sys_stacks
= scm_make_fluid ();
385 scm_c_define ("%stacks", scm_sys_stacks
);
387 scm_stack_type
= scm_make_vtable (scm_from_locale_string (SCM_STACK_LAYOUT
),
389 scm_set_struct_vtable_name_x (scm_stack_type
,
390 scm_from_latin1_symbol ("stack"));
391 #include "libguile/stacks.x"