| 1 | /* Copyright (C) 2012, 2013 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 | |
| 20 | \f |
| 21 | |
| 22 | #ifdef HAVE_CONFIG_H |
| 23 | # include <config.h> |
| 24 | #endif |
| 25 | |
| 26 | #include <assert.h> |
| 27 | |
| 28 | #include "libguile/_scm.h" |
| 29 | #include "libguile/control.h" |
| 30 | #include "libguile/eval.h" |
| 31 | #include "libguile/fluids.h" |
| 32 | #include "libguile/dynstack.h" |
| 33 | |
| 34 | |
| 35 | \f |
| 36 | |
| 37 | #define PROMPT_WORDS 5 |
| 38 | #define PROMPT_KEY(top) (SCM_PACK ((top)[0])) |
| 39 | #define PROMPT_FP(top) ((scm_t_ptrdiff) ((top)[1])) |
| 40 | #define PROMPT_SP(top) ((scm_t_ptrdiff) ((top)[2])) |
| 41 | #define PROMPT_IP(top) ((scm_t_uint32 *) ((top)[3])) |
| 42 | #define PROMPT_JMPBUF(top) ((scm_i_jmp_buf *) ((top)[4])) |
| 43 | |
| 44 | #define WINDER_WORDS 2 |
| 45 | #define WINDER_PROC(top) ((scm_t_guard) ((top)[0])) |
| 46 | #define WINDER_DATA(top) ((void *) ((top)[1])) |
| 47 | |
| 48 | #define DYNWIND_WORDS 2 |
| 49 | #define DYNWIND_ENTER(top) (SCM_PACK ((top)[0])) |
| 50 | #define DYNWIND_LEAVE(top) (SCM_PACK ((top)[1])) |
| 51 | |
| 52 | #define WITH_FLUID_WORDS 2 |
| 53 | #define WITH_FLUID_FLUID(top) (SCM_PACK ((top)[0])) |
| 54 | #define WITH_FLUID_VALUE_BOX(top) (SCM_PACK ((top)[1])) |
| 55 | |
| 56 | |
| 57 | \f |
| 58 | |
| 59 | static void |
| 60 | copy_scm_t_bits (scm_t_bits *dst, scm_t_bits *src, size_t n) |
| 61 | { |
| 62 | size_t i; |
| 63 | |
| 64 | for (i = 0; i < n; i++) |
| 65 | dst[i] = src[i]; |
| 66 | } |
| 67 | |
| 68 | static void |
| 69 | clear_scm_t_bits (scm_t_bits *items, size_t n) |
| 70 | { |
| 71 | size_t i; |
| 72 | |
| 73 | for (i = 0; i < n; i++) |
| 74 | items[i] = 0; |
| 75 | } |
| 76 | |
| 77 | /* Ensure space for N additional words. */ |
| 78 | static void |
| 79 | dynstack_ensure_space (scm_t_dynstack *dynstack, size_t n) |
| 80 | { |
| 81 | size_t capacity = SCM_DYNSTACK_CAPACITY (dynstack); |
| 82 | size_t height = SCM_DYNSTACK_HEIGHT (dynstack); |
| 83 | |
| 84 | n += SCM_DYNSTACK_HEADER_LEN; |
| 85 | |
| 86 | if (capacity < height + n) |
| 87 | { |
| 88 | scm_t_bits *new_base; |
| 89 | |
| 90 | while (capacity < height + n) |
| 91 | capacity = (capacity < 4) ? 8 : (capacity * 2); |
| 92 | |
| 93 | new_base = scm_gc_malloc (capacity * sizeof(scm_t_bits), "dynstack"); |
| 94 | |
| 95 | copy_scm_t_bits (new_base, dynstack->base, height); |
| 96 | clear_scm_t_bits (dynstack->base, height); |
| 97 | |
| 98 | dynstack->base = new_base; |
| 99 | dynstack->top = new_base + height; |
| 100 | dynstack->limit = new_base + capacity; |
| 101 | } |
| 102 | } |
| 103 | |
| 104 | static inline scm_t_bits * |
| 105 | push_dynstack_entry_unchecked (scm_t_dynstack *dynstack, |
| 106 | scm_t_dynstack_item_type type, |
| 107 | scm_t_bits flags, size_t len) |
| 108 | { |
| 109 | scm_t_bits *ret = dynstack->top; |
| 110 | |
| 111 | SCM_DYNSTACK_SET_TAG (dynstack->top, SCM_MAKE_DYNSTACK_TAG (type, flags, len)); |
| 112 | dynstack->top += SCM_DYNSTACK_HEADER_LEN + len; |
| 113 | SCM_DYNSTACK_SET_PREV_OFFSET (dynstack->top, SCM_DYNSTACK_HEADER_LEN + len); |
| 114 | |
| 115 | return ret; |
| 116 | } |
| 117 | |
| 118 | static inline scm_t_bits * |
| 119 | push_dynstack_entry (scm_t_dynstack *dynstack, |
| 120 | scm_t_dynstack_item_type type, |
| 121 | scm_t_bits flags, size_t len) |
| 122 | { |
| 123 | if (SCM_UNLIKELY (!SCM_DYNSTACK_HAS_SPACE (dynstack, len))) |
| 124 | dynstack_ensure_space (dynstack, len); |
| 125 | return push_dynstack_entry_unchecked (dynstack, type, flags, len); |
| 126 | } |
| 127 | |
| 128 | void |
| 129 | scm_dynstack_push_frame (scm_t_dynstack *dynstack, |
| 130 | scm_t_dynstack_frame_flags flags) |
| 131 | { |
| 132 | push_dynstack_entry (dynstack, SCM_DYNSTACK_TYPE_FRAME, flags, 0); |
| 133 | } |
| 134 | |
| 135 | void |
| 136 | scm_dynstack_push_rewinder (scm_t_dynstack *dynstack, |
| 137 | scm_t_dynstack_winder_flags flags, |
| 138 | scm_t_guard proc, void *data) |
| 139 | { |
| 140 | scm_t_bits *words; |
| 141 | |
| 142 | words = push_dynstack_entry (dynstack, SCM_DYNSTACK_TYPE_REWINDER, flags, |
| 143 | WINDER_WORDS); |
| 144 | words[0] = (scm_t_bits) proc; |
| 145 | words[1] = (scm_t_bits) data; |
| 146 | } |
| 147 | |
| 148 | void |
| 149 | scm_dynstack_push_unwinder (scm_t_dynstack *dynstack, |
| 150 | scm_t_dynstack_winder_flags flags, |
| 151 | scm_t_guard proc, void *data) |
| 152 | { |
| 153 | scm_t_bits *words; |
| 154 | |
| 155 | words = push_dynstack_entry (dynstack, SCM_DYNSTACK_TYPE_UNWINDER, flags, |
| 156 | WINDER_WORDS); |
| 157 | words[0] = (scm_t_bits) proc; |
| 158 | words[1] = (scm_t_bits) data; |
| 159 | } |
| 160 | |
| 161 | /* The fluid is stored on the stack, but the value has to be stored on the heap, |
| 162 | so that all continuations that capture this dynamic scope capture the same |
| 163 | binding. */ |
| 164 | void |
| 165 | scm_dynstack_push_fluid (scm_t_dynstack *dynstack, SCM fluid, SCM value, |
| 166 | SCM dynamic_state) |
| 167 | { |
| 168 | scm_t_bits *words; |
| 169 | SCM value_box; |
| 170 | |
| 171 | if (SCM_UNLIKELY (!SCM_FLUID_P (fluid))) |
| 172 | scm_wrong_type_arg ("with-fluid*", 0, fluid); |
| 173 | |
| 174 | value_box = scm_make_variable (value); |
| 175 | |
| 176 | words = push_dynstack_entry (dynstack, SCM_DYNSTACK_TYPE_WITH_FLUID, 0, |
| 177 | WITH_FLUID_WORDS); |
| 178 | words[0] = SCM_UNPACK (fluid); |
| 179 | words[1] = SCM_UNPACK (value_box); |
| 180 | |
| 181 | /* Go ahead and swap them. */ |
| 182 | scm_swap_fluid (fluid, value_box, dynamic_state); |
| 183 | } |
| 184 | |
| 185 | void |
| 186 | scm_dynstack_push_prompt (scm_t_dynstack *dynstack, |
| 187 | scm_t_dynstack_prompt_flags flags, |
| 188 | SCM key, |
| 189 | scm_t_ptrdiff fp_offset, scm_t_ptrdiff sp_offset, |
| 190 | scm_t_uint32 *ip, scm_i_jmp_buf *registers) |
| 191 | { |
| 192 | scm_t_bits *words; |
| 193 | |
| 194 | words = push_dynstack_entry (dynstack, SCM_DYNSTACK_TYPE_PROMPT, flags, |
| 195 | PROMPT_WORDS); |
| 196 | words[0] = SCM_UNPACK (key); |
| 197 | words[1] = (scm_t_bits) fp_offset; |
| 198 | words[2] = (scm_t_bits) sp_offset; |
| 199 | words[3] = (scm_t_bits) ip; |
| 200 | words[4] = (scm_t_bits) registers; |
| 201 | } |
| 202 | |
| 203 | void |
| 204 | scm_dynstack_push_dynwind (scm_t_dynstack *dynstack, SCM enter, SCM leave) |
| 205 | { |
| 206 | scm_t_bits *words; |
| 207 | |
| 208 | words = push_dynstack_entry (dynstack, SCM_DYNSTACK_TYPE_DYNWIND, 0, |
| 209 | DYNWIND_WORDS); |
| 210 | words[0] = SCM_UNPACK (enter); |
| 211 | words[1] = SCM_UNPACK (leave); |
| 212 | } |
| 213 | |
| 214 | static inline scm_t_bits |
| 215 | dynstack_pop (scm_t_dynstack *dynstack, scm_t_bits **words) |
| 216 | { |
| 217 | scm_t_bits *prev = SCM_DYNSTACK_PREV (dynstack->top); |
| 218 | scm_t_bits tag; |
| 219 | |
| 220 | if (SCM_UNLIKELY (!prev)) |
| 221 | abort (); |
| 222 | |
| 223 | SCM_DYNSTACK_SET_PREV_OFFSET (dynstack->top, 0); |
| 224 | dynstack->top = prev; |
| 225 | |
| 226 | tag = SCM_DYNSTACK_TAG (dynstack->top); |
| 227 | SCM_DYNSTACK_SET_TAG (dynstack->top, 0); |
| 228 | *words = dynstack->top; |
| 229 | |
| 230 | return tag; |
| 231 | } |
| 232 | |
| 233 | void |
| 234 | scm_dynstack_pop (scm_t_dynstack *dynstack) |
| 235 | { |
| 236 | scm_t_bits tag, *words; |
| 237 | tag = dynstack_pop (dynstack, &words); |
| 238 | clear_scm_t_bits (words, SCM_DYNSTACK_TAG_LEN (tag)); |
| 239 | } |
| 240 | |
| 241 | scm_t_dynstack * |
| 242 | scm_dynstack_capture_all (scm_t_dynstack *dynstack) |
| 243 | { |
| 244 | return scm_dynstack_capture (dynstack, SCM_DYNSTACK_FIRST (dynstack)); |
| 245 | } |
| 246 | |
| 247 | scm_t_dynstack * |
| 248 | scm_dynstack_capture (scm_t_dynstack *dynstack, scm_t_bits *item) |
| 249 | { |
| 250 | char *mem; |
| 251 | scm_t_dynstack *ret; |
| 252 | size_t len; |
| 253 | |
| 254 | assert (item >= SCM_DYNSTACK_FIRST (dynstack)); |
| 255 | assert (item <= dynstack->top); |
| 256 | |
| 257 | len = dynstack->top - item + SCM_DYNSTACK_HEADER_LEN; |
| 258 | mem = scm_gc_malloc (sizeof (*ret) + len * sizeof(scm_t_bits), "dynstack"); |
| 259 | ret = (scm_t_dynstack *) mem; |
| 260 | ret->base = (scm_t_bits *) (mem + sizeof (*ret)); |
| 261 | ret->limit = ret->base + len; |
| 262 | ret->top = ret->base + len; |
| 263 | |
| 264 | copy_scm_t_bits (ret->base, item - SCM_DYNSTACK_HEADER_LEN, len); |
| 265 | SCM_DYNSTACK_SET_PREV_OFFSET (SCM_DYNSTACK_FIRST (ret), 0); |
| 266 | |
| 267 | return ret; |
| 268 | } |
| 269 | |
| 270 | void |
| 271 | scm_dynstack_wind_1 (scm_t_dynstack *dynstack, scm_t_bits *item) |
| 272 | { |
| 273 | scm_t_bits tag = SCM_DYNSTACK_TAG (item); |
| 274 | scm_t_dynstack_item_type type = SCM_DYNSTACK_TAG_TYPE (tag); |
| 275 | scm_t_bits flags = SCM_DYNSTACK_TAG_FLAGS (tag); |
| 276 | size_t len = SCM_DYNSTACK_TAG_LEN (tag); |
| 277 | |
| 278 | switch (type) |
| 279 | { |
| 280 | case SCM_DYNSTACK_TYPE_FRAME: |
| 281 | if (!(flags & SCM_F_DYNSTACK_FRAME_REWINDABLE)) |
| 282 | scm_misc_error ("scm_dynstack_wind_1", |
| 283 | "cannot invoke continuation from this context", |
| 284 | SCM_EOL); |
| 285 | break; |
| 286 | |
| 287 | case SCM_DYNSTACK_TYPE_UNWINDER: |
| 288 | break; |
| 289 | |
| 290 | case SCM_DYNSTACK_TYPE_REWINDER: |
| 291 | WINDER_PROC (item) (WINDER_DATA (item)); |
| 292 | break; |
| 293 | |
| 294 | case SCM_DYNSTACK_TYPE_WITH_FLUID: |
| 295 | scm_swap_fluid (WITH_FLUID_FLUID (item), |
| 296 | WITH_FLUID_VALUE_BOX (item), |
| 297 | SCM_I_CURRENT_THREAD->dynamic_state); |
| 298 | break; |
| 299 | |
| 300 | case SCM_DYNSTACK_TYPE_PROMPT: |
| 301 | /* see vm_reinstate_partial_continuation */ |
| 302 | break; |
| 303 | |
| 304 | case SCM_DYNSTACK_TYPE_DYNWIND: |
| 305 | scm_call_0 (DYNWIND_ENTER (item)); |
| 306 | break; |
| 307 | |
| 308 | case SCM_DYNSTACK_TYPE_NONE: |
| 309 | default: |
| 310 | abort (); |
| 311 | } |
| 312 | |
| 313 | { |
| 314 | scm_t_bits *words = push_dynstack_entry (dynstack, type, flags, len); |
| 315 | |
| 316 | copy_scm_t_bits (words, item, len); |
| 317 | } |
| 318 | } |
| 319 | |
| 320 | scm_t_bits |
| 321 | scm_dynstack_unwind_1 (scm_t_dynstack *dynstack) |
| 322 | { |
| 323 | scm_t_bits tag; |
| 324 | scm_t_bits *words; |
| 325 | scm_t_dynstack_item_type type; |
| 326 | |
| 327 | tag = dynstack_pop (dynstack, &words); |
| 328 | |
| 329 | type = SCM_DYNSTACK_TAG_TYPE (tag); |
| 330 | |
| 331 | switch (type) |
| 332 | { |
| 333 | case SCM_DYNSTACK_TYPE_FRAME: |
| 334 | break; |
| 335 | |
| 336 | case SCM_DYNSTACK_TYPE_UNWINDER: |
| 337 | WINDER_PROC (words) (WINDER_DATA (words)); |
| 338 | clear_scm_t_bits (words, WINDER_WORDS); |
| 339 | break; |
| 340 | |
| 341 | case SCM_DYNSTACK_TYPE_REWINDER: |
| 342 | clear_scm_t_bits (words, WINDER_WORDS); |
| 343 | break; |
| 344 | |
| 345 | case SCM_DYNSTACK_TYPE_WITH_FLUID: |
| 346 | scm_swap_fluid (WITH_FLUID_FLUID (words), |
| 347 | WITH_FLUID_VALUE_BOX (words), |
| 348 | SCM_I_CURRENT_THREAD->dynamic_state); |
| 349 | clear_scm_t_bits (words, WITH_FLUID_WORDS); |
| 350 | break; |
| 351 | |
| 352 | case SCM_DYNSTACK_TYPE_PROMPT: |
| 353 | /* we could invalidate the prompt */ |
| 354 | clear_scm_t_bits (words, PROMPT_WORDS); |
| 355 | break; |
| 356 | |
| 357 | case SCM_DYNSTACK_TYPE_DYNWIND: |
| 358 | { |
| 359 | SCM proc = DYNWIND_LEAVE (words); |
| 360 | clear_scm_t_bits (words, DYNWIND_WORDS); |
| 361 | scm_call_0 (proc); |
| 362 | } |
| 363 | break; |
| 364 | |
| 365 | case SCM_DYNSTACK_TYPE_NONE: |
| 366 | default: |
| 367 | abort (); |
| 368 | } |
| 369 | |
| 370 | return tag; |
| 371 | } |
| 372 | |
| 373 | void |
| 374 | scm_dynstack_wind (scm_t_dynstack *dynstack, scm_t_bits *item) |
| 375 | { |
| 376 | for (; SCM_DYNSTACK_TAG (item); item = SCM_DYNSTACK_NEXT (item)) |
| 377 | scm_dynstack_wind_1 (dynstack, item); |
| 378 | } |
| 379 | |
| 380 | void |
| 381 | scm_dynstack_unwind (scm_t_dynstack *dynstack, scm_t_bits *base) |
| 382 | { |
| 383 | while (dynstack->top > base) |
| 384 | scm_dynstack_unwind_1 (dynstack); |
| 385 | } |
| 386 | |
| 387 | static int |
| 388 | same_entries (scm_t_bits *walk_a, scm_t_bits *next_a, |
| 389 | scm_t_bits *walk_b, scm_t_bits *next_b) |
| 390 | { |
| 391 | if (SCM_DYNSTACK_TAG (walk_a) != SCM_DYNSTACK_TAG (walk_b)) |
| 392 | return 0; |
| 393 | |
| 394 | if (next_a - walk_a != next_b - walk_b) |
| 395 | return 0; |
| 396 | |
| 397 | assert (SCM_DYNSTACK_PREV_OFFSET (next_a) == next_a - walk_a); |
| 398 | assert (SCM_DYNSTACK_PREV_OFFSET (next_b) == next_b - walk_b); |
| 399 | |
| 400 | while (walk_a != next_a) |
| 401 | if (*(walk_a++) != *(walk_b++)) |
| 402 | return 0; |
| 403 | |
| 404 | return 1; |
| 405 | } |
| 406 | |
| 407 | static ptrdiff_t |
| 408 | shared_prefix_length (scm_t_dynstack *a, scm_t_dynstack *b) |
| 409 | { |
| 410 | scm_t_bits *walk_a, *next_a, *walk_b, *next_b; |
| 411 | |
| 412 | walk_a = SCM_DYNSTACK_FIRST (a); |
| 413 | walk_b = SCM_DYNSTACK_FIRST (b); |
| 414 | |
| 415 | next_a = SCM_DYNSTACK_NEXT (walk_a); |
| 416 | next_b = SCM_DYNSTACK_NEXT (walk_b); |
| 417 | |
| 418 | while (next_a && next_b && same_entries (walk_a, next_a, walk_b, next_b)) |
| 419 | { |
| 420 | walk_a = next_a; |
| 421 | walk_b = next_b; |
| 422 | |
| 423 | next_a = SCM_DYNSTACK_NEXT (walk_a); |
| 424 | next_b = SCM_DYNSTACK_NEXT (walk_b); |
| 425 | } |
| 426 | |
| 427 | return walk_a - a->base; |
| 428 | } |
| 429 | |
| 430 | scm_t_bits * |
| 431 | scm_dynstack_unwind_fork (scm_t_dynstack *dynstack, scm_t_dynstack *branch) |
| 432 | { |
| 433 | ptrdiff_t join_height; |
| 434 | |
| 435 | join_height = shared_prefix_length (dynstack, branch); |
| 436 | |
| 437 | scm_dynstack_unwind (dynstack, dynstack->base + join_height); |
| 438 | |
| 439 | return branch->base + join_height; |
| 440 | } |
| 441 | |
| 442 | scm_t_bits* |
| 443 | scm_dynstack_find_prompt (scm_t_dynstack *dynstack, SCM key, |
| 444 | scm_t_dynstack_prompt_flags *flags, |
| 445 | scm_t_ptrdiff *fp_offset, scm_t_ptrdiff *sp_offset, |
| 446 | scm_t_uint32 **ip, scm_i_jmp_buf **registers) |
| 447 | { |
| 448 | scm_t_bits *walk; |
| 449 | |
| 450 | for (walk = SCM_DYNSTACK_PREV (dynstack->top); walk; |
| 451 | walk = SCM_DYNSTACK_PREV (walk)) |
| 452 | { |
| 453 | scm_t_bits tag = SCM_DYNSTACK_TAG (walk); |
| 454 | |
| 455 | if (SCM_DYNSTACK_TAG_TYPE (tag) == SCM_DYNSTACK_TYPE_PROMPT |
| 456 | && scm_is_eq (PROMPT_KEY (walk), key)) |
| 457 | { |
| 458 | if (flags) |
| 459 | *flags = SCM_DYNSTACK_TAG_FLAGS (tag); |
| 460 | if (fp_offset) |
| 461 | *fp_offset = PROMPT_FP (walk); |
| 462 | if (sp_offset) |
| 463 | *sp_offset = PROMPT_SP (walk); |
| 464 | if (ip) |
| 465 | *ip = PROMPT_IP (walk); |
| 466 | if (registers) |
| 467 | *registers = PROMPT_JMPBUF (walk); |
| 468 | return walk; |
| 469 | } |
| 470 | } |
| 471 | |
| 472 | return NULL; |
| 473 | } |
| 474 | |
| 475 | void |
| 476 | scm_dynstack_wind_prompt (scm_t_dynstack *dynstack, scm_t_bits *item, |
| 477 | scm_t_ptrdiff reloc, scm_i_jmp_buf *registers) |
| 478 | { |
| 479 | scm_t_bits tag = SCM_DYNSTACK_TAG (item); |
| 480 | |
| 481 | if (SCM_DYNSTACK_TAG_TYPE (tag) != SCM_DYNSTACK_TYPE_PROMPT) |
| 482 | abort (); |
| 483 | |
| 484 | scm_dynstack_push_prompt (dynstack, |
| 485 | SCM_DYNSTACK_TAG_FLAGS (tag), |
| 486 | PROMPT_KEY (item), |
| 487 | PROMPT_FP (item) + reloc, |
| 488 | PROMPT_SP (item) + reloc, |
| 489 | PROMPT_IP (item), |
| 490 | registers); |
| 491 | } |
| 492 | |
| 493 | void |
| 494 | scm_dynstack_unwind_frame (scm_t_dynstack *dynstack) |
| 495 | { |
| 496 | /* Unwind up to and including the next frame entry. */ |
| 497 | while (1) |
| 498 | { |
| 499 | scm_t_bits tag, *words; |
| 500 | |
| 501 | tag = dynstack_pop (dynstack, &words); |
| 502 | |
| 503 | switch (SCM_DYNSTACK_TAG_TYPE (tag)) |
| 504 | { |
| 505 | case SCM_DYNSTACK_TYPE_FRAME: |
| 506 | return; |
| 507 | case SCM_DYNSTACK_TYPE_REWINDER: |
| 508 | clear_scm_t_bits (words, WINDER_WORDS); |
| 509 | continue; |
| 510 | case SCM_DYNSTACK_TYPE_UNWINDER: |
| 511 | { |
| 512 | scm_t_guard proc = WINDER_PROC (words); |
| 513 | void *data = WINDER_DATA (words); |
| 514 | clear_scm_t_bits (words, WINDER_WORDS); |
| 515 | if (SCM_DYNSTACK_TAG_FLAGS (tag) & SCM_F_DYNSTACK_WINDER_EXPLICIT) |
| 516 | proc (data); |
| 517 | continue; |
| 518 | } |
| 519 | default: |
| 520 | /* We should only see winders. */ |
| 521 | abort (); |
| 522 | } |
| 523 | } |
| 524 | } |
| 525 | |
| 526 | /* This function must not allocate. */ |
| 527 | void |
| 528 | scm_dynstack_unwind_fluid (scm_t_dynstack *dynstack, SCM dynamic_state) |
| 529 | { |
| 530 | scm_t_bits tag, *words; |
| 531 | size_t len; |
| 532 | |
| 533 | tag = dynstack_pop (dynstack, &words); |
| 534 | len = SCM_DYNSTACK_TAG_LEN (tag); |
| 535 | |
| 536 | assert (SCM_DYNSTACK_TAG_TYPE (tag) == SCM_DYNSTACK_TYPE_WITH_FLUID); |
| 537 | assert (len == WITH_FLUID_WORDS); |
| 538 | |
| 539 | scm_swap_fluid (WITH_FLUID_FLUID (words), WITH_FLUID_VALUE_BOX (words), |
| 540 | dynamic_state); |
| 541 | clear_scm_t_bits (words, len); |
| 542 | } |
| 543 | |
| 544 | |
| 545 | /* |
| 546 | Local Variables: |
| 547 | c-file-style: "gnu" |
| 548 | End: |
| 549 | */ |