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 | 81 | reify_partial_continuation (SCM vm, |
9121d9f1 AW |
82 | SCM *saved_fp, |
83 | SCM *saved_sp, | |
84 | scm_t_uint32 *saved_ip, | |
9d381ba4 | 85 | scm_i_jmp_buf *saved_registers, |
9ede013f | 86 | scm_t_dynstack *dynstack, |
9d381ba4 | 87 | scm_i_jmp_buf *current_registers) |
cee1d22c | 88 | { |
d76de871 | 89 | SCM vm_cont; |
cee1d22c | 90 | scm_t_uint32 flags; |
88e5cade | 91 | SCM *bottom_fp; |
cee1d22c | 92 | |
cee1d22c | 93 | flags = SCM_F_VM_CONT_PARTIAL; |
9d381ba4 AW |
94 | /* If we are aborting to a prompt that has the same registers as those |
95 | of the abort, it means there are no intervening C frames on the | |
96 | stack, and so the continuation can be relocated elsewhere on the | |
97 | stack: it is rewindable. */ | |
98 | if (saved_registers && saved_registers == current_registers) | |
cee1d22c AW |
99 | flags |= SCM_F_VM_CONT_REWINDABLE; |
100 | ||
88e5cade AW |
101 | /* Walk the stack down until we find the first frame after saved_fp. |
102 | We will save the stack down to that frame. It used to be that we | |
103 | could determine the stack bottom in O(1) time, but that's no longer | |
104 | the case, since the thunk application doesn't occur where the | |
105 | prompt is saved. */ | |
106 | for (bottom_fp = SCM_VM_DATA (vm)->fp; | |
107 | SCM_FRAME_DYNAMIC_LINK (bottom_fp) > saved_fp; | |
108 | bottom_fp = SCM_FRAME_DYNAMIC_LINK (bottom_fp)); | |
109 | ||
110 | if (SCM_FRAME_DYNAMIC_LINK (bottom_fp) != saved_fp) | |
111 | abort(); | |
6d804376 | 112 | |
840ec334 | 113 | /* Capture from the top of the thunk application frame up to the end. */ |
b636cdb0 | 114 | vm_cont = scm_i_vm_capture_stack (&SCM_FRAME_LOCAL (bottom_fp, 0), |
cee1d22c AW |
115 | SCM_VM_DATA (vm)->fp, |
116 | SCM_VM_DATA (vm)->sp, | |
6d804376 | 117 | SCM_VM_DATA (vm)->ip, |
9ede013f | 118 | dynstack, |
cee1d22c AW |
119 | flags); |
120 | ||
d76de871 | 121 | return make_partial_continuation (vm_cont); |
cee1d22c AW |
122 | } |
123 | ||
d2964315 | 124 | void |
9d381ba4 AW |
125 | scm_c_abort (SCM vm, SCM tag, size_t n, SCM *argv, |
126 | scm_i_jmp_buf *current_registers) | |
eaefabee | 127 | { |
9ede013f AW |
128 | SCM cont; |
129 | scm_t_dynstack *dynstack = &SCM_I_CURRENT_THREAD->dynstack; | |
130 | scm_t_bits *prompt; | |
9ede013f | 131 | scm_t_dynstack_prompt_flags flags; |
9d381ba4 | 132 | SCM *fp, *sp; |
9121d9f1 | 133 | scm_t_uint32 *ip; |
9d381ba4 | 134 | scm_i_jmp_buf *registers; |
eaefabee AW |
135 | size_t i; |
136 | ||
9d381ba4 AW |
137 | prompt = scm_dynstack_find_prompt (dynstack, tag, |
138 | &flags, &fp, &sp, &ip, ®isters); | |
9ede013f AW |
139 | |
140 | if (!prompt) | |
9f074518 | 141 | scm_misc_error ("abort", "Abort to unknown prompt", scm_list_1 (tag)); |
eaefabee | 142 | |
9ede013f AW |
143 | /* Only reify if the continuation referenced in the handler. */ |
144 | if (flags & SCM_F_DYNSTACK_PROMPT_ESCAPE_ONLY) | |
145 | cont = SCM_BOOL_F; | |
146 | else | |
147 | { | |
148 | scm_t_dynstack *captured; | |
cee1d22c | 149 | |
9ede013f | 150 | captured = scm_dynstack_capture (dynstack, SCM_DYNSTACK_NEXT (prompt)); |
9d381ba4 AW |
151 | cont = reify_partial_continuation (vm, fp, sp, ip, registers, captured, |
152 | current_registers); | |
9ede013f | 153 | } |
8684029d | 154 | |
9ede013f AW |
155 | /* Unwind. */ |
156 | scm_dynstack_unwind (dynstack, prompt); | |
eaefabee | 157 | |
8684029d LC |
158 | /* Unwinding may have changed the current thread's VM, so use the |
159 | new one. */ | |
160 | vm = scm_the_vm (); | |
161 | ||
eaefabee | 162 | /* Restore VM regs */ |
9d381ba4 AW |
163 | SCM_VM_DATA (vm)->fp = fp; |
164 | SCM_VM_DATA (vm)->sp = sp; | |
165 | SCM_VM_DATA (vm)->ip = ip; | |
eaefabee | 166 | |
9ede013f | 167 | /* Since we're jumping down, we should always have enough space. */ |
eaefabee AW |
168 | if (SCM_VM_DATA (vm)->sp + n + 1 >= SCM_VM_DATA (vm)->stack_limit) |
169 | abort (); | |
170 | ||
171 | /* Push vals */ | |
cee1d22c | 172 | *(++(SCM_VM_DATA (vm)->sp)) = cont; |
eaefabee AW |
173 | for (i = 0; i < n; i++) |
174 | *(++(SCM_VM_DATA (vm)->sp)) = argv[i]; | |
c6cd692f AW |
175 | if (flags & SCM_F_DYNSTACK_PROMPT_PUSH_NARGS) |
176 | *(++(SCM_VM_DATA (vm)->sp)) = scm_from_size_t (n+1); /* +1 for continuation */ | |
eaefabee AW |
177 | |
178 | /* Jump! */ | |
9d381ba4 | 179 | SCM_I_LONGJMP (*registers, 1); |
eaefabee AW |
180 | |
181 | /* Shouldn't get here */ | |
182 | abort (); | |
183 | } | |
adaf86ec | 184 | |
38504994 AW |
185 | SCM_DEFINE (scm_abort_to_prompt_star, "abort-to-prompt*", 2, 0, 0, |
186 | (SCM tag, SCM args), | |
187 | "Abort to the nearest prompt with tag @var{tag}, yielding the\n" | |
188 | "values in the list, @var{args}.") | |
189 | #define FUNC_NAME s_scm_abort_to_prompt_star | |
b9c100d0 | 190 | { |
747022e4 | 191 | SCM *argv; |
2b14df4b AW |
192 | size_t i; |
193 | long n; | |
747022e4 AW |
194 | |
195 | SCM_VALIDATE_LIST_COPYLEN (SCM_ARG2, args, n); | |
196 | argv = alloca (sizeof (SCM)*n); | |
197 | for (i = 0; i < n; i++, args = scm_cdr (args)) | |
198 | argv[i] = scm_car (args); | |
199 | ||
9d381ba4 | 200 | scm_c_abort (scm_the_vm (), tag, n, argv, NULL); |
747022e4 | 201 | |
2d026f04 AW |
202 | /* Oh, what, you're still here? The abort must have been reinstated. Actually, |
203 | that's quite impossible, given that we're already in C-land here, so... | |
204 | abort! */ | |
205 | ||
206 | abort (); | |
b9c100d0 | 207 | } |
747022e4 | 208 | #undef FUNC_NAME |
b9c100d0 | 209 | |
3ccee391 AW |
210 | void |
211 | scm_init_control (void) | |
b9c100d0 | 212 | { |
69c96006 | 213 | #include "libguile/control.x" |
b9c100d0 AW |
214 | } |
215 | ||
216 | /* | |
217 | Local Variables: | |
218 | c-file-style: "gnu" | |
219 | End: | |
220 | */ |