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b9c100d0 AW |
1 | /* Copyright (C) 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 "libguile/_scm.h" | |
24 | #include "libguile/control.h" | |
cee1d22c AW |
25 | #include "libguile/objcodes.h" |
26 | #include "libguile/instructions.h" | |
adaf86ec | 27 | #include "libguile/vm.h" |
b9c100d0 AW |
28 | |
29 | \f | |
30 | ||
3ccee391 | 31 | |
adaf86ec | 32 | SCM |
d2964315 | 33 | scm_c_make_prompt (SCM k, SCM *fp, SCM *sp, scm_t_uint8 *abort_ip, |
adbdfd6d AW |
34 | scm_t_uint8 escape_only_p, scm_t_int64 vm_cookie, |
35 | SCM winds) | |
adaf86ec AW |
36 | { |
37 | scm_t_bits tag; | |
adaf86ec AW |
38 | struct scm_prompt_registers *regs; |
39 | ||
40 | tag = scm_tc7_prompt; | |
adaf86ec | 41 | if (escape_only_p) |
211fcbc8 | 42 | tag |= (SCM_F_PROMPT_ESCAPE<<8); |
adaf86ec AW |
43 | |
44 | regs = scm_gc_malloc_pointerless (sizeof (*regs), "prompt registers"); | |
d2964315 AW |
45 | regs->fp = fp; |
46 | regs->sp = sp; | |
47 | regs->ip = abort_ip; | |
2d026f04 | 48 | regs->cookie = vm_cookie; |
adaf86ec | 49 | |
adbdfd6d AW |
50 | return scm_double_cell (tag, SCM_UNPACK (k), (scm_t_bits)regs, |
51 | SCM_UNPACK (winds)); | |
adaf86ec AW |
52 | } |
53 | ||
b8af64db AW |
54 | /* Only to be called if the SCM_PROMPT_SETJMP returns 1 */ |
55 | SCM | |
56 | scm_i_prompt_pop_abort_args_x (SCM prompt) | |
57 | { | |
58 | size_t i, n; | |
59 | SCM vals = SCM_EOL; | |
60 | ||
61 | n = scm_to_size_t (SCM_PROMPT_REGISTERS (prompt)->sp[0]); | |
62 | for (i = 0; i < n; i++) | |
63 | vals = scm_cons (SCM_PROMPT_REGISTERS (prompt)->sp[-(i + 1)], vals); | |
64 | ||
65 | /* The abort did reset the VM's registers, but then these values | |
66 | were pushed on; so we need to pop them ourselves. */ | |
67 | SCM_VM_DATA (scm_the_vm ())->sp -= n + 1; | |
68 | /* FIXME NULLSTACK */ | |
69 | ||
70 | return vals; | |
71 | } | |
72 | ||
73 | ||
cee1d22c AW |
74 | #ifdef WORDS_BIGENDIAN |
75 | #define OBJCODE_HEADER(main,meta) 0, 0, 0, main, 0, 0, 0, meta+8 | |
76 | #define META_HEADER(meta) 0, 0, 0, meta, 0, 0, 0, 0 | |
77 | #else | |
78 | #define OBJCODE_HEADER(main,meta) main, 0, 0, 0, meta+8, 0, 0, 0 | |
79 | #define META_HEADER(meta) meta, 0, 0, 0, 0, 0, 0, 0 | |
80 | #endif | |
81 | ||
cee1d22c AW |
82 | #define ALIGN_PTR(type,p,align) (type*)(ROUND_UP (((scm_t_bits)p), align)) |
83 | ||
84 | #ifdef SCM_ALIGNED | |
85 | #define SCM_DECLARE_STATIC_ALIGNED_ARRAY(type, sym)\ | |
86 | static const type sym[] | |
87 | #define SCM_STATIC_ALIGNED_ARRAY(alignment, type, sym)\ | |
88 | static SCM_ALIGNED (alignment) const type sym[] | |
89 | #else | |
90 | #define SCM_DECLARE_STATIC_ALIGNED_ARRAY(type, sym)\ | |
91 | static type *sym | |
92 | #define SCM_STATIC_ALIGNED_ARRAY(alignment, type, sym) \ | |
93 | SCM_SNARF_INIT(sym = scm_malloc (sizeof(sym##__unaligned) + alignment - 1); \ | |
94 | sym = ALIGN_PTR (type, sym, alignment); \ | |
95 | memcpy (sym, sym##__unaligned, sizeof(sym##__unaligned));) \ | |
96 | static type *sym = NULL; \ | |
97 | static const type sym##__unaligned[] | |
98 | #endif | |
99 | ||
100 | #define STATIC_OBJCODE_TAG \ | |
101 | SCM_PACK (scm_tc7_objcode | (SCM_F_OBJCODE_IS_STATIC << 8)) | |
102 | ||
103 | #define SCM_STATIC_OBJCODE(sym) \ | |
104 | SCM_DECLARE_STATIC_ALIGNED_ARRAY (scm_t_uint8, sym##__bytecode); \ | |
105 | SCM_STATIC_ALIGNED_ARRAY (8, scm_t_cell, sym##__cells) = { \ | |
106 | { STATIC_OBJCODE_TAG, SCM_PACK (sym##__bytecode) }, \ | |
107 | { SCM_BOOL_F, SCM_PACK (0) } \ | |
108 | }; \ | |
109 | static const SCM sym = SCM_PACK (sym##__cells); \ | |
110 | SCM_STATIC_ALIGNED_ARRAY (8, scm_t_uint8, sym##__bytecode) | |
111 | ||
112 | ||
113 | SCM_STATIC_OBJCODE (cont_objcode) = { | |
114 | /* Like in continuations.c, but with partial-cont-call. */ | |
115 | OBJCODE_HEADER (8, 19), | |
116 | /* leave args on the stack */ | |
117 | /* 0 */ scm_op_object_ref, 0, /* push scm_vm_cont object */ | |
118 | /* 2 */ scm_op_object_ref, 1, /* push internal winds */ | |
9a1c6f1f AW |
119 | /* 4 */ scm_op_partial_cont_call, /* and go! */ |
120 | /* 5 */ scm_op_nop, scm_op_nop, scm_op_nop, /* pad to 8 bytes */ | |
cee1d22c AW |
121 | /* 8 */ |
122 | ||
123 | /* We could put some meta-info to say that this proc is a continuation. Not sure | |
124 | how to do that, though. */ | |
125 | META_HEADER (19), | |
126 | /* 0 */ scm_op_make_eol, /* bindings */ | |
127 | /* 1 */ scm_op_make_eol, /* sources */ | |
9a1c6f1f | 128 | /* 2 */ scm_op_make_int8, 0, scm_op_make_int8, 5, /* arity: from ip 0 to ip 7 */ |
cee1d22c AW |
129 | /* 6 */ scm_op_make_int8_0, /* the arity is 0 required args */ |
130 | /* 7 */ scm_op_make_int8_0, /* 0 optionals */ | |
131 | /* 8 */ scm_op_make_true, /* and a rest arg */ | |
132 | /* 9 */ scm_op_list, 0, 5, /* make a list of those 5 vals */ | |
133 | /* 12 */ scm_op_list, 0, 1, /* and the arities will be a list of that one list */ | |
134 | /* 15 */ scm_op_list, 0, 3, /* pack bindings, sources, and arities into list */ | |
135 | /* 18 */ scm_op_return /* and return */ | |
136 | /* 19 */ | |
137 | }; | |
138 | ||
139 | ||
140 | static SCM | |
141 | reify_partial_continuation (SCM vm, SCM prompt, SCM extwinds, | |
142 | scm_t_int64 cookie) | |
143 | { | |
144 | SCM vm_cont, dynwinds, intwinds = SCM_EOL, ret; | |
145 | scm_t_uint32 flags; | |
146 | ||
147 | /* No need to reify if the continuation is never referenced in the handler. */ | |
148 | if (SCM_PROMPT_ESCAPE_P (prompt)) | |
149 | return SCM_BOOL_F; | |
150 | ||
151 | dynwinds = scm_i_dynwinds (); | |
152 | while (!scm_is_eq (dynwinds, extwinds)) | |
153 | { | |
154 | intwinds = scm_cons (scm_car (dynwinds), intwinds); | |
155 | dynwinds = scm_cdr (dynwinds); | |
156 | } | |
157 | ||
158 | flags = SCM_F_VM_CONT_PARTIAL; | |
159 | if (cookie >= 0 && SCM_PROMPT_REGISTERS (prompt)->cookie == cookie) | |
160 | flags |= SCM_F_VM_CONT_REWINDABLE; | |
161 | ||
6d804376 AW |
162 | /* Since non-escape continuations should begin with a thunk application, the |
163 | first bit of the stack should be a frame, with the saved fp equal to the fp | |
164 | that was current when the prompt was made. */ | |
165 | if ((SCM*)(SCM_PROMPT_REGISTERS (prompt)->sp[1]) | |
166 | != SCM_PROMPT_REGISTERS (prompt)->fp) | |
167 | abort (); | |
168 | ||
169 | /* Capture from the top of the thunk application frame up to the end. Set an | |
170 | MVRA only, as the post-abort code is in an MV context. */ | |
171 | vm_cont = scm_i_vm_capture_stack (SCM_PROMPT_REGISTERS (prompt)->sp + 4, | |
cee1d22c AW |
172 | SCM_VM_DATA (vm)->fp, |
173 | SCM_VM_DATA (vm)->sp, | |
6d804376 AW |
174 | NULL, |
175 | SCM_VM_DATA (vm)->ip, | |
cee1d22c AW |
176 | flags); |
177 | ||
178 | ret = scm_make_program (cont_objcode, | |
9a1c6f1f | 179 | scm_vector (scm_list_2 (vm_cont, intwinds)), |
cee1d22c AW |
180 | SCM_BOOL_F); |
181 | SCM_SET_CELL_WORD_0 (ret, | |
2150e9a8 | 182 | SCM_CELL_WORD_0 (ret) | SCM_F_PROGRAM_IS_PARTIAL_CONTINUATION); |
cee1d22c AW |
183 | return ret; |
184 | } | |
185 | ||
d2964315 | 186 | void |
cee1d22c | 187 | scm_c_abort (SCM vm, SCM tag, size_t n, SCM *argv, scm_t_int64 cookie) |
eaefabee | 188 | { |
cee1d22c | 189 | SCM cont, winds, prompt = SCM_BOOL_F; |
eaefabee AW |
190 | long delta; |
191 | size_t i; | |
192 | ||
193 | /* Search the wind list for an appropriate prompt. | |
194 | "Waiter, please bring us the wind list." */ | |
195 | for (winds = scm_i_dynwinds (), delta = 0; | |
196 | scm_is_pair (winds); | |
197 | winds = SCM_CDR (winds), delta++) | |
198 | { | |
199 | SCM elt = SCM_CAR (winds); | |
200 | if (SCM_PROMPT_P (elt) && scm_is_eq (SCM_PROMPT_TAG (elt), tag)) | |
201 | { | |
202 | prompt = elt; | |
203 | break; | |
204 | } | |
205 | } | |
206 | ||
c6a32a2c | 207 | /* If we didn't find anything, raise an error. */ |
eaefabee | 208 | if (scm_is_false (prompt)) |
9f074518 | 209 | scm_misc_error ("abort", "Abort to unknown prompt", scm_list_1 (tag)); |
eaefabee | 210 | |
cee1d22c AW |
211 | cont = reify_partial_continuation (vm, prompt, winds, cookie); |
212 | ||
eaefabee AW |
213 | /* Unwind once more, beyond the prompt. */ |
214 | winds = SCM_CDR (winds), delta++; | |
215 | ||
216 | /* Unwind */ | |
217 | scm_dowinds (winds, delta); | |
218 | ||
219 | /* Restore VM regs */ | |
220 | SCM_VM_DATA (vm)->fp = SCM_PROMPT_REGISTERS (prompt)->fp; | |
221 | SCM_VM_DATA (vm)->sp = SCM_PROMPT_REGISTERS (prompt)->sp; | |
222 | SCM_VM_DATA (vm)->ip = SCM_PROMPT_REGISTERS (prompt)->ip; | |
223 | ||
224 | /* Since we're jumping down, we should always have enough space */ | |
225 | if (SCM_VM_DATA (vm)->sp + n + 1 >= SCM_VM_DATA (vm)->stack_limit) | |
226 | abort (); | |
227 | ||
228 | /* Push vals */ | |
cee1d22c | 229 | *(++(SCM_VM_DATA (vm)->sp)) = cont; |
eaefabee AW |
230 | for (i = 0; i < n; i++) |
231 | *(++(SCM_VM_DATA (vm)->sp)) = argv[i]; | |
232 | *(++(SCM_VM_DATA (vm)->sp)) = scm_from_size_t (n+1); /* +1 for continuation */ | |
233 | ||
234 | /* Jump! */ | |
235 | SCM_I_LONGJMP (SCM_PROMPT_REGISTERS (prompt)->regs, 1); | |
236 | ||
237 | /* Shouldn't get here */ | |
238 | abort (); | |
239 | } | |
adaf86ec | 240 | |
2d026f04 | 241 | SCM_DEFINE (scm_at_abort, "@abort", 2, 0, 0, (SCM tag, SCM args), |
747022e4 | 242 | "Abort to the nearest prompt with tag @var{tag}.") |
2d026f04 | 243 | #define FUNC_NAME s_scm_at_abort |
b9c100d0 | 244 | { |
747022e4 AW |
245 | SCM *argv; |
246 | size_t i, n; | |
247 | ||
248 | SCM_VALIDATE_LIST_COPYLEN (SCM_ARG2, args, n); | |
249 | argv = alloca (sizeof (SCM)*n); | |
250 | for (i = 0; i < n; i++, args = scm_cdr (args)) | |
251 | argv[i] = scm_car (args); | |
252 | ||
cee1d22c | 253 | scm_c_abort (scm_the_vm (), tag, n, argv, -1); |
747022e4 | 254 | |
2d026f04 AW |
255 | /* Oh, what, you're still here? The abort must have been reinstated. Actually, |
256 | that's quite impossible, given that we're already in C-land here, so... | |
257 | abort! */ | |
258 | ||
259 | abort (); | |
b9c100d0 | 260 | } |
747022e4 | 261 | #undef FUNC_NAME |
b9c100d0 | 262 | |
bbb2ecd1 AW |
263 | void |
264 | scm_i_prompt_print (SCM exp, SCM port, scm_print_state *pstate SCM_UNUSED) | |
265 | { | |
266 | scm_puts ("#<prompt ", port); | |
267 | scm_intprint (SCM_UNPACK (exp), 16, port); | |
268 | scm_putc ('>', port); | |
269 | } | |
270 | ||
3ccee391 AW |
271 | void |
272 | scm_init_control (void) | |
b9c100d0 | 273 | { |
69c96006 | 274 | #include "libguile/control.x" |
b9c100d0 AW |
275 | } |
276 | ||
277 | /* | |
278 | Local Variables: | |
279 | c-file-style: "gnu" | |
280 | End: | |
281 | */ |