Commit | Line | Data |
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38504994 | 1 | /* Copyright (C) 2010, 2011, 2012, 2013 Free Software Foundation, Inc. |
b9c100d0 AW |
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 | ||
cdd47ec7 LC |
23 | #include <alloca.h> |
24 | ||
b9c100d0 AW |
25 | #include "libguile/_scm.h" |
26 | #include "libguile/control.h" | |
d76de871 | 27 | #include "libguile/programs.h" |
cee1d22c | 28 | #include "libguile/instructions.h" |
adaf86ec | 29 | #include "libguile/vm.h" |
b9c100d0 AW |
30 | |
31 | \f | |
32 | ||
9ede013f AW |
33 | #define PROMPT_ESCAPE_P(p) \ |
34 | (SCM_DYNSTACK_TAG_FLAGS (SCM_DYNSTACK_TAG (p)) \ | |
35 | & SCM_F_DYNSTACK_PROMPT_ESCAPE_ONLY) | |
3ccee391 | 36 | |
9ede013f | 37 | \f |
adaf86ec | 38 | |
9ede013f | 39 | |
9ede013f | 40 | /* Only to be called if the SCM_I_SETJMP returns 1 */ |
b8af64db | 41 | SCM |
572eef50 | 42 | scm_i_prompt_pop_abort_args_x (SCM vm) |
b8af64db AW |
43 | { |
44 | size_t i, n; | |
45 | SCM vals = SCM_EOL; | |
46 | ||
572eef50 | 47 | n = scm_to_size_t (SCM_VM_DATA (vm)->sp[0]); |
b8af64db | 48 | for (i = 0; i < n; i++) |
572eef50 | 49 | vals = scm_cons (SCM_VM_DATA (vm)->sp[-(i + 1)], vals); |
b8af64db AW |
50 | |
51 | /* The abort did reset the VM's registers, but then these values | |
52 | were pushed on; so we need to pop them ourselves. */ | |
572eef50 | 53 | SCM_VM_DATA (vm)->sp -= n + 1; |
b8af64db AW |
54 | /* FIXME NULLSTACK */ |
55 | ||
56 | return vals; | |
57 | } | |
58 | ||
59 | ||
d76de871 AW |
60 | static const scm_t_uint32 compose_continuation_code[] = |
61 | { | |
62 | SCM_PACK_RTL_24 (scm_rtl_op_compose_continuation, 0) | |
63 | }; | |
cee1d22c | 64 | |
5556c175 | 65 | |
d76de871 AW |
66 | static SCM |
67 | make_partial_continuation (SCM vm_cont) | |
68 | { | |
69 | scm_t_bits nfree = 1; | |
70 | scm_t_bits flags = SCM_F_PROGRAM_IS_PARTIAL_CONTINUATION; | |
71 | SCM ret; | |
cee1d22c | 72 | |
d76de871 AW |
73 | ret = scm_words (scm_tc7_rtl_program | (nfree << 16) | flags, nfree + 2); |
74 | SCM_SET_CELL_WORD_1 (ret, compose_continuation_code); | |
75 | SCM_RTL_PROGRAM_FREE_VARIABLE_SET (ret, 0, vm_cont); | |
cee1d22c | 76 | |
d76de871 AW |
77 | return ret; |
78 | } | |
cee1d22c AW |
79 | |
80 | static SCM | |
9d381ba4 AW |
81 | reify_partial_continuation (SCM vm, |
82 | SCM *saved_fp, SCM *saved_sp, scm_t_uint8 *saved_ip, | |
83 | scm_i_jmp_buf *saved_registers, | |
9ede013f | 84 | scm_t_dynstack *dynstack, |
9d381ba4 | 85 | scm_i_jmp_buf *current_registers) |
cee1d22c | 86 | { |
d76de871 | 87 | SCM vm_cont; |
cee1d22c | 88 | scm_t_uint32 flags; |
88e5cade | 89 | SCM *bottom_fp; |
cee1d22c | 90 | |
cee1d22c | 91 | flags = SCM_F_VM_CONT_PARTIAL; |
9d381ba4 AW |
92 | /* If we are aborting to a prompt that has the same registers as those |
93 | of the abort, it means there are no intervening C frames on the | |
94 | stack, and so the continuation can be relocated elsewhere on the | |
95 | stack: it is rewindable. */ | |
96 | if (saved_registers && saved_registers == current_registers) | |
cee1d22c AW |
97 | flags |= SCM_F_VM_CONT_REWINDABLE; |
98 | ||
88e5cade AW |
99 | /* Walk the stack down until we find the first frame after saved_fp. |
100 | We will save the stack down to that frame. It used to be that we | |
101 | could determine the stack bottom in O(1) time, but that's no longer | |
102 | the case, since the thunk application doesn't occur where the | |
103 | prompt is saved. */ | |
104 | for (bottom_fp = SCM_VM_DATA (vm)->fp; | |
105 | SCM_FRAME_DYNAMIC_LINK (bottom_fp) > saved_fp; | |
106 | bottom_fp = SCM_FRAME_DYNAMIC_LINK (bottom_fp)); | |
107 | ||
108 | if (SCM_FRAME_DYNAMIC_LINK (bottom_fp) != saved_fp) | |
109 | abort(); | |
6d804376 | 110 | |
840ec334 | 111 | /* Capture from the top of the thunk application frame up to the end. */ |
88e5cade | 112 | vm_cont = scm_i_vm_capture_stack (bottom_fp - 1, |
cee1d22c AW |
113 | SCM_VM_DATA (vm)->fp, |
114 | SCM_VM_DATA (vm)->sp, | |
6d804376 | 115 | SCM_VM_DATA (vm)->ip, |
9ede013f | 116 | dynstack, |
cee1d22c AW |
117 | flags); |
118 | ||
d76de871 | 119 | return make_partial_continuation (vm_cont); |
cee1d22c AW |
120 | } |
121 | ||
d2964315 | 122 | void |
9d381ba4 AW |
123 | scm_c_abort (SCM vm, SCM tag, size_t n, SCM *argv, |
124 | scm_i_jmp_buf *current_registers) | |
eaefabee | 125 | { |
9ede013f AW |
126 | SCM cont; |
127 | scm_t_dynstack *dynstack = &SCM_I_CURRENT_THREAD->dynstack; | |
128 | scm_t_bits *prompt; | |
9ede013f | 129 | scm_t_dynstack_prompt_flags flags; |
9d381ba4 AW |
130 | SCM *fp, *sp; |
131 | scm_t_uint8 *ip; | |
132 | scm_i_jmp_buf *registers; | |
eaefabee AW |
133 | size_t i; |
134 | ||
9d381ba4 AW |
135 | prompt = scm_dynstack_find_prompt (dynstack, tag, |
136 | &flags, &fp, &sp, &ip, ®isters); | |
9ede013f AW |
137 | |
138 | if (!prompt) | |
9f074518 | 139 | scm_misc_error ("abort", "Abort to unknown prompt", scm_list_1 (tag)); |
eaefabee | 140 | |
9ede013f AW |
141 | /* Only reify if the continuation referenced in the handler. */ |
142 | if (flags & SCM_F_DYNSTACK_PROMPT_ESCAPE_ONLY) | |
143 | cont = SCM_BOOL_F; | |
144 | else | |
145 | { | |
146 | scm_t_dynstack *captured; | |
cee1d22c | 147 | |
9ede013f | 148 | captured = scm_dynstack_capture (dynstack, SCM_DYNSTACK_NEXT (prompt)); |
9d381ba4 AW |
149 | cont = reify_partial_continuation (vm, fp, sp, ip, registers, captured, |
150 | current_registers); | |
9ede013f | 151 | } |
8684029d | 152 | |
9ede013f AW |
153 | /* Unwind. */ |
154 | scm_dynstack_unwind (dynstack, prompt); | |
eaefabee | 155 | |
8684029d LC |
156 | /* Unwinding may have changed the current thread's VM, so use the |
157 | new one. */ | |
158 | vm = scm_the_vm (); | |
159 | ||
eaefabee | 160 | /* Restore VM regs */ |
9d381ba4 AW |
161 | SCM_VM_DATA (vm)->fp = fp; |
162 | SCM_VM_DATA (vm)->sp = sp; | |
163 | SCM_VM_DATA (vm)->ip = ip; | |
eaefabee | 164 | |
9ede013f | 165 | /* Since we're jumping down, we should always have enough space. */ |
eaefabee AW |
166 | if (SCM_VM_DATA (vm)->sp + n + 1 >= SCM_VM_DATA (vm)->stack_limit) |
167 | abort (); | |
168 | ||
169 | /* Push vals */ | |
cee1d22c | 170 | *(++(SCM_VM_DATA (vm)->sp)) = cont; |
eaefabee AW |
171 | for (i = 0; i < n; i++) |
172 | *(++(SCM_VM_DATA (vm)->sp)) = argv[i]; | |
c6cd692f AW |
173 | if (flags & SCM_F_DYNSTACK_PROMPT_PUSH_NARGS) |
174 | *(++(SCM_VM_DATA (vm)->sp)) = scm_from_size_t (n+1); /* +1 for continuation */ | |
eaefabee AW |
175 | |
176 | /* Jump! */ | |
9d381ba4 | 177 | SCM_I_LONGJMP (*registers, 1); |
eaefabee AW |
178 | |
179 | /* Shouldn't get here */ | |
180 | abort (); | |
181 | } | |
adaf86ec | 182 | |
38504994 AW |
183 | SCM_DEFINE (scm_abort_to_prompt_star, "abort-to-prompt*", 2, 0, 0, |
184 | (SCM tag, SCM args), | |
185 | "Abort to the nearest prompt with tag @var{tag}, yielding the\n" | |
186 | "values in the list, @var{args}.") | |
187 | #define FUNC_NAME s_scm_abort_to_prompt_star | |
b9c100d0 | 188 | { |
747022e4 | 189 | SCM *argv; |
2b14df4b AW |
190 | size_t i; |
191 | long n; | |
747022e4 AW |
192 | |
193 | SCM_VALIDATE_LIST_COPYLEN (SCM_ARG2, args, n); | |
194 | argv = alloca (sizeof (SCM)*n); | |
195 | for (i = 0; i < n; i++, args = scm_cdr (args)) | |
196 | argv[i] = scm_car (args); | |
197 | ||
9d381ba4 | 198 | scm_c_abort (scm_the_vm (), tag, n, argv, NULL); |
747022e4 | 199 | |
2d026f04 AW |
200 | /* Oh, what, you're still here? The abort must have been reinstated. Actually, |
201 | that's quite impossible, given that we're already in C-land here, so... | |
202 | abort! */ | |
203 | ||
204 | abort (); | |
b9c100d0 | 205 | } |
747022e4 | 206 | #undef FUNC_NAME |
b9c100d0 | 207 | |
3ccee391 AW |
208 | void |
209 | scm_init_control (void) | |
b9c100d0 | 210 | { |
69c96006 | 211 | #include "libguile/control.x" |
b9c100d0 AW |
212 | } |
213 | ||
214 | /* | |
215 | Local Variables: | |
216 | c-file-style: "gnu" | |
217 | End: | |
218 | */ |