| 1 | #include "coroutine.h" |
| 2 | #include <assert.h> |
| 3 | #include <setjmp.h> |
| 4 | #include <stdbool.h> |
| 5 | #include <stddef.h> |
| 6 | #include "cor_platform.h" |
| 7 | |
| 8 | // see CPython again, this time from ctypes.h |
| 9 | #if (defined (__SVR4) && defined (__sun)) || defined(COROUTINE_HAVE_ALLOCA_H) |
| 10 | # include <alloca.h> |
| 11 | #elif defined(MS_WIN32) |
| 12 | # include <malloc.h> |
| 13 | #endif |
| 14 | |
| 15 | /* If the system does not define alloca(), we have to hope for a compiler builtin. */ |
| 16 | #ifndef alloca |
| 17 | # if defined __GNUC__ || (__clang_major__ >= 4) |
| 18 | # define alloca __builtin_alloca |
| 19 | # else |
| 20 | # error "Could not define alloca() on your platform." |
| 21 | # endif |
| 22 | #endif |
| 23 | |
| 24 | static void Coroutine_RunNext(void); |
| 25 | static void _Coroutine_Continue(Coroutine *cor, void *value, bool early); |
| 26 | static unsigned char *StackTopNow(void); |
| 27 | |
| 28 | /////////////////////////////////////////////////////////////////////////////// |
| 29 | // 2-way linked lists... |
| 30 | // |
| 31 | // Brought inline here to avoid namespace polution |
| 32 | /////////////////////////////////////////////////////////////////////////////// |
| 33 | |
| 34 | typedef struct List_Link List_Link; |
| 35 | struct List_Link { |
| 36 | List_Link *next; |
| 37 | List_Link *prev; |
| 38 | }; |
| 39 | |
| 40 | typedef struct List_Head List_Head; |
| 41 | struct List_Head { |
| 42 | union { |
| 43 | struct { |
| 44 | List_Link link; |
| 45 | List_Link *filler; |
| 46 | } fwd; |
| 47 | struct { |
| 48 | List_Link *filler; |
| 49 | List_Link link; |
| 50 | } back; |
| 51 | }; |
| 52 | }; |
| 53 | |
| 54 | |
| 55 | static inline bool List_IsEmpty( |
| 56 | const List_Head *list |
| 57 | ){ |
| 58 | return list->fwd.link.next == &list->back.link; |
| 59 | } |
| 60 | |
| 61 | |
| 62 | static inline List_Link *List_GetHead( |
| 63 | const List_Head *list |
| 64 | ){ |
| 65 | return List_IsEmpty(list) ? NULL : list->fwd.link.next; |
| 66 | } |
| 67 | |
| 68 | |
| 69 | // static inline List_Link *List_GetTail( |
| 70 | // const List_Head *list |
| 71 | // ){ |
| 72 | // return List_IsEmpty(list) ? NULL : list->back.link.prev; |
| 73 | // } |
| 74 | |
| 75 | |
| 76 | #define OFFSETOF(Container, Field) ((char *)&((Container *)4)->Field - (char *)(Container *)4) |
| 77 | #define List_Link_Container(Container, Link, link) ((Container *)((char *)(link) - OFFSETOF(Container, Link))) |
| 78 | |
| 79 | |
| 80 | static inline void List_Init( |
| 81 | List_Head *list |
| 82 | ){ |
| 83 | list->fwd.link.next = &list->back.link; |
| 84 | list->fwd.link.prev = NULL; |
| 85 | list->back.link.prev = &list->fwd.link; |
| 86 | } |
| 87 | |
| 88 | |
| 89 | static inline void List_AddHead( |
| 90 | List_Head *list, |
| 91 | List_Link *link |
| 92 | ){ |
| 93 | List_Link *first = list->fwd.link.next; |
| 94 | link->next = first; |
| 95 | link->prev = &list->fwd.link; |
| 96 | first->prev = link; |
| 97 | list->fwd.link.next = link; |
| 98 | } |
| 99 | |
| 100 | |
| 101 | static inline void List_AddTail( |
| 102 | List_Head *list, |
| 103 | List_Link *link |
| 104 | ){ |
| 105 | List_Link *last = list->back.link.prev; |
| 106 | link->prev = last; |
| 107 | link->next = &list->back.link; |
| 108 | last->next = link; |
| 109 | list->back.link.prev = link; |
| 110 | } |
| 111 | |
| 112 | |
| 113 | static inline void List_Remove( |
| 114 | List_Link *link |
| 115 | ){ |
| 116 | link->prev->next = link->next; |
| 117 | link->next->prev = link->prev; |
| 118 | } |
| 119 | |
| 120 | /////////////////////////////////////////////////////////////////////////////// |
| 121 | // ...2-way linked lists |
| 122 | /////////////////////////////////////////////////////////////////////////////// |
| 123 | |
| 124 | typedef struct Coroutines Coroutines; |
| 125 | |
| 126 | enum { |
| 127 | Coroutines_Idle, |
| 128 | Coroutines_Starting, |
| 129 | Coroutines_Started, |
| 130 | Coroutines_Active, |
| 131 | Coroutines_Stopping |
| 132 | }; |
| 133 | |
| 134 | enum { |
| 135 | Chunk_Initial, |
| 136 | Chunk_Create, |
| 137 | Chunk_Enter |
| 138 | }; |
| 139 | |
| 140 | typedef enum Coroutine_State { |
| 141 | Coroutine_Free, |
| 142 | Coroutine_Idle, |
| 143 | Coroutine_Running, |
| 144 | Coroutine_Waiting, |
| 145 | Coroutine_Complete |
| 146 | } Coroutine_State; |
| 147 | |
| 148 | enum { |
| 149 | Coroutines_Init, |
| 150 | Coroutines_AllocatedChunk, |
| 151 | Coroutines_CoroutineComplete, |
| 152 | }; |
| 153 | |
| 154 | struct Coroutine { |
| 155 | Coroutines *coroutines; // so can work with it off-thread |
| 156 | List_Link link; // for whichever list it's on |
| 157 | jmp_buf buf; // how to get back to it |
| 158 | unsigned char *guard; // where the stack overrun guard is |
| 159 | Coroutine_Start start; // entry point |
| 160 | void *entry_param; // to pass to start |
| 161 | void *value; // yielded/returned |
| 162 | unsigned char *stack_top; // recorded at yield |
| 163 | Coroutine_State state; |
| 164 | }; |
| 165 | |
| 166 | struct Coroutines { |
| 167 | _Cor_Mutex mutex; |
| 168 | jmp_buf controller; // to return from Coroutine_Run |
| 169 | jmp_buf chunk_allocated;// for chunk allocation |
| 170 | unsigned char *guard; // the stack guard for the startup sequence |
| 171 | |
| 172 | // singletons |
| 173 | Coroutine *tip; // top of stack chunk |
| 174 | Coroutine *active; // currently running coroutine |
| 175 | Coroutine *primary; // Coroutine_Run coroutine |
| 176 | unsigned char *stack_limit; // when not NULL, where the stack finishes |
| 177 | |
| 178 | // lists |
| 179 | List_Head free; |
| 180 | List_Head inactive; // idle or complete |
| 181 | List_Head runable; // running or waiting to run |
| 182 | List_Head waiting; // yielded / waiting to run |
| 183 | _Cor_Mutex waiting_mutex; |
| 184 | |
| 185 | // Summary of the system |
| 186 | Coroutine_Report report; |
| 187 | |
| 188 | // state |
| 189 | char state; |
| 190 | }; |
| 191 | |
| 192 | _Cor_thread_local Coroutines g_c; |
| 193 | |
| 194 | static void stack_chunk_chunk(Coroutine *parent, size_t chunk_size); |
| 195 | static void stack_chunk_base(void); |
| 196 | |
| 197 | |
| 198 | #define GUARD_PATTERN_SIZE (4) |
| 199 | // Check whether the guard is intact |
| 200 | static inline bool Check_Guard( |
| 201 | unsigned char *guard |
| 202 | ){ |
| 203 | return !guard || |
| 204 | (guard[0] == 0xde && |
| 205 | guard[1] == 0xad && |
| 206 | guard[2] == 0xbe && |
| 207 | guard[3] == 0xef); |
| 208 | } |
| 209 | |
| 210 | |
| 211 | static inline void Apply_Guard(unsigned char *guard){ |
| 212 | guard[0] = 0xde; |
| 213 | guard[1] = 0xad; |
| 214 | guard[2] = 0xbe; |
| 215 | guard[3] = 0xef; |
| 216 | } |
| 217 | |
| 218 | |
| 219 | static bool Coroutine_StackHasNotOverrun(void){ |
| 220 | unsigned char *stack_top = StackTopNow(); |
| 221 | unsigned char *stack_limit = g_c.stack_limit; |
| 222 | if (stack_limit && stack_top < stack_limit){ |
| 223 | // current stack top is beyond limit - we are overrunning NOW |
| 224 | return false; |
| 225 | } |
| 226 | Coroutine *me = g_c.active; |
| 227 | if (!me){ |
| 228 | return true; |
| 229 | } |
| 230 | if (me->guard){ |
| 231 | return Check_Guard(me->guard); |
| 232 | } |
| 233 | unsigned char *coroutine_limit; |
| 234 | if (!stack_limit || stack_limit <= (unsigned char *)me - 2*COROUTINE_STACK_SIZE){ |
| 235 | // no stack limit, or can start a coroutine, so limit ourselves to one unit of coroutine stack |
| 236 | coroutine_limit = (unsigned char *)me - 1*COROUTINE_STACK_SIZE + GUARD_PATTERN_SIZE; |
| 237 | } else { |
| 238 | // can't start coroutine, and have a stack limit - use that |
| 239 | coroutine_limit = stack_limit; |
| 240 | } |
| 241 | return stack_top >= coroutine_limit; |
| 242 | } |
| 243 | |
| 244 | |
| 245 | static void Coroutine_PrimeStackChunks(void) |
| 246 | { |
| 247 | unsigned char chunk_of_stack[COROUTINE_STARTUP_STACK_SIZE + GUARD_PATTERN_SIZE]; |
| 248 | Apply_Guard(chunk_of_stack); |
| 249 | assert(Check_Guard(chunk_of_stack)); |
| 250 | |
| 251 | // Stacks grow down in memory (almost always), so if the caller of this function changes |
| 252 | // the guard before entering the coroutine system, it has overrun the startup stack |
| 253 | g_c.guard = chunk_of_stack; |
| 254 | |
| 255 | stack_chunk_base(); |
| 256 | } |
| 257 | |
| 258 | |
| 259 | static void stack_chunk_chunk( |
| 260 | Coroutine *parent, |
| 261 | size_t chunk_size |
| 262 | ){ |
| 263 | unsigned char *chunk_of_stack = alloca(chunk_size); |
| 264 | #if COROUTINE_RECORD_LOWEST_HEADROOM |
| 265 | for (size_t i = 0; i <= chunk_size-GUARD_PATTERN_SIZE; i += GUARD_PATTERN_SIZE){ |
| 266 | Apply_Guard(&chunk_of_stack[i]); |
| 267 | } |
| 268 | #else |
| 269 | Apply_Guard(chunk_of_stack); |
| 270 | #endif |
| 271 | parent->guard = chunk_of_stack; |
| 272 | stack_chunk_base(); |
| 273 | } |
| 274 | |
| 275 | |
| 276 | static void stack_chunk_base( |
| 277 | void |
| 278 | ){ |
| 279 | Coroutine here; |
| 280 | here.state = Coroutine_Free; |
| 281 | here.guard = NULL; |
| 282 | here.coroutines = &g_c; |
| 283 | List_AddHead(&g_c.free, &here.link); |
| 284 | g_c.report.coroutines_pool_size += 1; |
| 285 | g_c.tip = &here; |
| 286 | for(;;){ |
| 287 | switch (setjmp(here.buf)) { |
| 288 | case Chunk_Initial: |
| 289 | if (here.state == Coroutine_Free){ |
| 290 | // return to the coroutine allocator |
| 291 | longjmp(g_c.chunk_allocated, 1); |
| 292 | } else { |
| 293 | assert(here.state == Coroutine_Complete); |
| 294 | // we finish here to ensure the setjmp is redone |
| 295 | if (g_c.primary == &here) { |
| 296 | // if primary coroutine - return to Coroutine_Run |
| 297 | longjmp(g_c.controller, Coroutines_CoroutineComplete); |
| 298 | } |
| 299 | _Cor_Mutex_Unlock(&g_c.mutex); |
| 300 | Coroutine_RunNext(); |
| 301 | assert(false); |
| 302 | } |
| 303 | case Chunk_Create: |
| 304 | // Request to create a new chunk on the stack |
| 305 | // We're here if the coroutine is: |
| 306 | // Allocated, but not 'run' (Coroutine_Idle) |
| 307 | // Run, but not not entered yet (Coroutine_Running) |
| 308 | // Completed (Coroutine_Complete) |
| 309 | assert(here.state == Coroutine_Idle || here.state == Coroutine_Running || here.state == Coroutine_Complete); |
| 310 | unsigned char *ideal_limit = (unsigned char *)&here - COROUTINE_STACK_SIZE; |
| 311 | stack_chunk_chunk(&here, StackTopNow() - ideal_limit); |
| 312 | assert(false); |
| 313 | case Chunk_Enter: |
| 314 | // request to start a coroutine (ie use the chunk for a coroutine) |
| 315 | // arrive here with mutex locked |
| 316 | assert(here.state == Coroutine_Running); |
| 317 | g_c.active = &here; |
| 318 | _Cor_Mutex_Unlock(&g_c.mutex); |
| 319 | here.value = here.start(here.entry_param); |
| 320 | |
| 321 | // check the guard |
| 322 | assert(Check_Guard(here.guard)); |
| 323 | |
| 324 | _Cor_Mutex_Lock(&g_c.mutex); |
| 325 | g_c.active = NULL; |
| 326 | assert(here.state == Coroutine_Running); |
| 327 | List_Remove(&here.link); |
| 328 | here.state = Coroutine_Complete; |
| 329 | List_AddTail(&g_c.inactive, &here.link); |
| 330 | // Coroutine has completed |
| 331 | // Loop round to redo the setjmp() - if this coroutine yielded, then the setjmp will |
| 332 | // need reseting |
| 333 | } |
| 334 | } |
| 335 | } |
| 336 | |
| 337 | |
| 338 | static void Coroutine_RunNext(void) |
| 339 | { |
| 340 | // arrive here with mutex unlocked |
| 341 | _Cor_Mutex_Lock(&g_c.waiting_mutex); |
| 342 | _Cor_Mutex_Lock(&g_c.mutex); |
| 343 | Coroutine *next = List_Link_Container(Coroutine, link, List_GetHead(&g_c.runable)); |
| 344 | assert(next->state == Coroutine_Running); |
| 345 | longjmp(next->buf, Chunk_Enter); |
| 346 | assert(false); |
| 347 | } |
| 348 | |
| 349 | |
| 350 | void Coroutine_StartSystem(void) |
| 351 | { |
| 352 | assert(g_c.state == Coroutines_Idle); |
| 353 | g_c.state = Coroutines_Starting; |
| 354 | |
| 355 | _Cor_Mutex_ctor(&g_c.mutex); |
| 356 | |
| 357 | g_c.tip = NULL; |
| 358 | g_c.active = NULL; |
| 359 | |
| 360 | List_Init(&g_c.free); |
| 361 | List_Init(&g_c.inactive); |
| 362 | List_Init(&g_c.runable); |
| 363 | List_Init(&g_c.waiting); |
| 364 | _Cor_Mutex_ctor(&g_c.waiting_mutex); |
| 365 | _Cor_Mutex_Lock(&g_c.waiting_mutex); |
| 366 | |
| 367 | g_c.report.coroutines_created = 0; |
| 368 | g_c.report.coroutines_pool_size = 0; |
| 369 | |
| 370 | // prime the chunk system |
| 371 | if (!setjmp(g_c.chunk_allocated)){ |
| 372 | Coroutine_PrimeStackChunks(); |
| 373 | assert(false); |
| 374 | } |
| 375 | |
| 376 | assert(g_c.state == Coroutines_Starting); |
| 377 | g_c.state = Coroutines_Started; |
| 378 | } |
| 379 | |
| 380 | |
| 381 | void Coroutine_SetStackLimit(void *limit){ |
| 382 | assert(!limit || !(g_c.state == Coroutines_Started || g_c.state == Coroutines_Active) || (unsigned char *)limit < (unsigned char *)g_c.tip); |
| 383 | g_c.stack_limit = limit; |
| 384 | } |
| 385 | |
| 386 | |
| 387 | Coroutine_Report Coroutine_StopSystem(void) |
| 388 | { |
| 389 | _Cor_Mutex_Lock(&g_c.mutex); |
| 390 | assert(g_c.state == Coroutines_Started); |
| 391 | g_c.state = Coroutines_Stopping; |
| 392 | |
| 393 | uintptr_t stackminheadroom;; |
| 394 | #if COROUTINE_RECORD_LOWEST_HEADROOM |
| 395 | stackminheadroom = COROUTINE_STACK_SIZE; |
| 396 | for (List_Link *link = g_c.free.fwd.link.next; link->next; link = link->next){ |
| 397 | Coroutine *cor = List_Link_Container(Coroutine, link, link); |
| 398 | if (cor->guard){ |
| 399 | for (uintptr_t i = 4; i < COROUTINE_STACK_SIZE-3; i += 4){ |
| 400 | if (!Check_Guard(&cor->guard[i])){ |
| 401 | stackminheadroom = i < stackminheadroom ? i : stackminheadroom; |
| 402 | break; |
| 403 | } |
| 404 | } |
| 405 | } |
| 406 | } |
| 407 | #else |
| 408 | stackminheadroom = 0; |
| 409 | #endif |
| 410 | g_c.report.lowest_headroom = stackminheadroom; |
| 411 | |
| 412 | assert(List_IsEmpty(&g_c.inactive)); |
| 413 | _Cor_Mutex_Unlock(&g_c.waiting_mutex); |
| 414 | _Cor_Mutex_dtor(&g_c.waiting_mutex); |
| 415 | |
| 416 | assert(g_c.state == Coroutines_Stopping); |
| 417 | g_c.state = Coroutines_Idle; |
| 418 | _Cor_Mutex_Unlock(&g_c.mutex); |
| 419 | _Cor_Mutex_dtor(&g_c.mutex); |
| 420 | |
| 421 | return g_c.report; |
| 422 | } |
| 423 | |
| 424 | |
| 425 | void Coroutine_Run_Coroutine( |
| 426 | Coroutine *cor, |
| 427 | void *value |
| 428 | ){ |
| 429 | Coroutines *cors = cor->coroutines; |
| 430 | assert(&g_c == cors); |
| 431 | _Cor_Mutex_Lock(&cors->mutex); |
| 432 | assert(cors->state == Coroutines_Started); |
| 433 | cors->state = Coroutines_Active; |
| 434 | cors->primary = cor; |
| 435 | |
| 436 | _Coroutine_Continue(cor, value, true); |
| 437 | |
| 438 | if (!setjmp(cors->controller)){ |
| 439 | _Cor_Mutex_Unlock(&cors->mutex); |
| 440 | |
| 441 | // check the guard |
| 442 | assert(Check_Guard(cors->guard)); |
| 443 | |
| 444 | // start the first coroutine |
| 445 | Coroutine_RunNext(); |
| 446 | } |
| 447 | // arrive here with mutex locked |
| 448 | assert(List_IsEmpty(&cors->runable)); |
| 449 | assert(List_IsEmpty(&cors->waiting)); |
| 450 | assert(cors->state == Coroutines_Active); |
| 451 | cors->state = Coroutines_Started; |
| 452 | _Cor_Mutex_Unlock(&cors->mutex); |
| 453 | } |
| 454 | |
| 455 | |
| 456 | void *Coroutine_Run( |
| 457 | Coroutine_Start start, |
| 458 | void *value |
| 459 | ){ |
| 460 | if (g_c.active){ |
| 461 | return start(value); |
| 462 | } |
| 463 | assert(g_c.state == Coroutines_Idle || g_c.state == Coroutines_Started); |
| 464 | bool need_start = g_c.state == Coroutines_Idle; |
| 465 | if (need_start){ |
| 466 | Coroutine_StartSystem(); |
| 467 | } |
| 468 | Coroutine *cor = Coroutine_New(start); |
| 469 | assert(cor); |
| 470 | Coroutine_Run_Coroutine(cor, value); |
| 471 | void *res = Coroutine_GetValue(cor); |
| 472 | Coroutine_Delete(cor); |
| 473 | if (need_start){ |
| 474 | Coroutine_StopSystem(); |
| 475 | } |
| 476 | return res; |
| 477 | } |
| 478 | |
| 479 | |
| 480 | Coroutine *Coroutine_New( |
| 481 | Coroutine_Start start |
| 482 | ){ |
| 483 | assert((g_c.state == Coroutines_Started && List_IsEmpty(&g_c.inactive)) || g_c.state == Coroutines_Active); |
| 484 | assert(Coroutine_StackHasNotOverrun()); |
| 485 | |
| 486 | // if none free - add one |
| 487 | if (List_IsEmpty(&g_c.free)){ |
| 488 | // no free stack blocks |
| 489 | if (g_c.stack_limit && g_c.stack_limit > (unsigned char *)g_c.tip - 2*COROUTINE_STACK_SIZE){ |
| 490 | // no space for a new stack block |
| 491 | return NULL; |
| 492 | } |
| 493 | Coroutine *tip = g_c.tip; |
| 494 | Coroutine *me = g_c.active; |
| 495 | if (tip == me) { |
| 496 | if (!setjmp(g_c.chunk_allocated)){ |
| 497 | unsigned char *ideal_limit = (unsigned char *)me - COROUTINE_STACK_SIZE; |
| 498 | stack_chunk_chunk(me, StackTopNow() - ideal_limit); |
| 499 | } |
| 500 | } else { |
| 501 | if (!setjmp(g_c.chunk_allocated)){ |
| 502 | longjmp(tip->buf, Chunk_Create); |
| 503 | } |
| 504 | } |
| 505 | } |
| 506 | |
| 507 | Coroutine *cor = List_Link_Container(Coroutine, link, List_GetHead(&g_c.free)); |
| 508 | assert(cor->state == Coroutine_Free); |
| 509 | cor->state = Coroutine_Idle; |
| 510 | cor->start = start; |
| 511 | cor->value = NULL; |
| 512 | List_Remove(&cor->link); |
| 513 | List_AddHead(&g_c.inactive, &cor->link); |
| 514 | |
| 515 | g_c.report.coroutines_created += 1; |
| 516 | |
| 517 | return cor; |
| 518 | } |
| 519 | |
| 520 | |
| 521 | void Coroutine_Delete( |
| 522 | Coroutine *cor |
| 523 | ){ |
| 524 | assert(Coroutine_StackHasNotOverrun()); |
| 525 | if (cor){ |
| 526 | Coroutines *cors = cor->coroutines; |
| 527 | _Cor_Mutex_Lock(&cors->mutex); |
| 528 | assert(cor->state == Coroutine_Idle || cor->state == Coroutine_Complete); |
| 529 | cor->state = Coroutine_Free; |
| 530 | List_Remove(&cor->link); |
| 531 | List_AddTail(&cors->free, &cor->link); |
| 532 | _Cor_Mutex_Unlock(&cors->mutex); |
| 533 | } |
| 534 | } |
| 535 | |
| 536 | |
| 537 | // Coroutine_Continue, assuming the mutex is claimed |
| 538 | static void _Coroutine_Continue( |
| 539 | Coroutine *cor, |
| 540 | void *value, |
| 541 | bool early |
| 542 | ){ |
| 543 | Coroutines *cors = cor->coroutines; |
| 544 | assert(cor->state == Coroutine_Idle || cor->state == Coroutine_Waiting); |
| 545 | cor->entry_param = value; |
| 546 | cor->state = Coroutine_Running; |
| 547 | List_Remove(&cor->link); |
| 548 | if ( early ) { |
| 549 | List_AddHead(&cors->runable, &cor->link); |
| 550 | } else { |
| 551 | List_AddTail(&cors->runable, &cor->link); |
| 552 | } |
| 553 | _Cor_Mutex_Unlock(&cors->waiting_mutex); |
| 554 | } |
| 555 | |
| 556 | |
| 557 | void Coroutine_Continue( |
| 558 | Coroutine *cor, |
| 559 | void *value, |
| 560 | bool early |
| 561 | ){ |
| 562 | assert(Coroutine_StackHasNotOverrun()); |
| 563 | Coroutines *cors = cor->coroutines; |
| 564 | _Cor_Mutex_Lock(&cors->mutex); |
| 565 | _Coroutine_Continue(cor, value, early); |
| 566 | _Cor_Mutex_Unlock(&cors->mutex); |
| 567 | } |
| 568 | |
| 569 | |
| 570 | void *Coroutine_Yield( |
| 571 | void *value, |
| 572 | Coroutine_YieldCallback on_yield, |
| 573 | void *yield_me |
| 574 | ){ |
| 575 | Coroutine *me = g_c.active; |
| 576 | assert(me); |
| 577 | assert(Coroutine_StackHasNotOverrun()); |
| 578 | |
| 579 | _Cor_Mutex_Lock(&g_c.mutex); |
| 580 | Coroutines *cors = me->coroutines; |
| 581 | assert(me && me->state == Coroutine_Running && cors == &g_c); |
| 582 | me->stack_top = StackTopNow(); |
| 583 | me->value = value; |
| 584 | me->state = Coroutine_Waiting; |
| 585 | |
| 586 | List_Remove(&me->link); |
| 587 | if (!List_IsEmpty(&cors->runable)){ |
| 588 | _Cor_Mutex_Unlock(&cors->waiting_mutex); |
| 589 | } |
| 590 | List_AddTail(&cors->waiting, &me->link); |
| 591 | |
| 592 | switch (setjmp(me->buf)){ |
| 593 | case Chunk_Initial: |
| 594 | _Cor_Mutex_Unlock(&cors->mutex); |
| 595 | on_yield(yield_me); |
| 596 | Coroutine_RunNext(); |
| 597 | assert(false); |
| 598 | case Chunk_Create: |
| 599 | assert(me == g_c.tip); |
| 600 | unsigned char *ideal_limit = (unsigned char *)me - COROUTINE_STACK_SIZE; |
| 601 | stack_chunk_chunk(me, me->stack_top - ideal_limit); |
| 602 | assert(false); |
| 603 | case Chunk_Enter: |
| 604 | // arrive here with mutex locked |
| 605 | cors->active = me; |
| 606 | assert(Coroutine_StackHasNotOverrun()); |
| 607 | // when we return here - we are running again |
| 608 | assert(me->state == Coroutine_Running); |
| 609 | void *res = me->entry_param; |
| 610 | _Cor_Mutex_Unlock(&cors->mutex); |
| 611 | return res; |
| 612 | } |
| 613 | return NULL; |
| 614 | } |
| 615 | |
| 616 | |
| 617 | void *Coroutine_GetValue( |
| 618 | Coroutine *cor |
| 619 | ){ |
| 620 | return cor->value; |
| 621 | } |
| 622 | |
| 623 | |
| 624 | Coroutine *Coroutine_GetActive(void) |
| 625 | { |
| 626 | return g_c.active; |
| 627 | } |
| 628 | |
| 629 | |
| 630 | intptr_t Coroutine_GetStackHeadroom(void){ |
| 631 | assert(Coroutine_StackHasNotOverrun()); |
| 632 | Coroutine *me = g_c.active; |
| 633 | if (!me){ |
| 634 | // no active coroutine |
| 635 | unsigned char *stack_limit = g_c.stack_limit; |
| 636 | if (stack_limit){ |
| 637 | // no stack limit - assume we'll use COROUTINE_STACK_SIZE |
| 638 | return StackTopNow() - stack_limit; |
| 639 | } else { |
| 640 | // no information where the stack ends - return something |
| 641 | return COROUTINE_STACK_SIZE; |
| 642 | } |
| 643 | } |
| 644 | unsigned char *stack_top = StackTopNow(); |
| 645 | if (me->guard){ |
| 646 | // guard established - that's where we'll measure to |
| 647 | return stack_top - me->guard; |
| 648 | } |
| 649 | intptr_t used = (unsigned char *)me - stack_top; |
| 650 | unsigned char *stack_limit = g_c.stack_limit; |
| 651 | if (!stack_limit){ |
| 652 | // no stack limit - assume we'll use COROUTINE_STACK_SIZE |
| 653 | return COROUTINE_STACK_SIZE - used; |
| 654 | } |
| 655 | intptr_t available = (unsigned char *)me - stack_limit; |
| 656 | if (available < (intptr_t)(2*COROUTINE_STACK_SIZE)){ |
| 657 | // can't start another coroutine, so whatever's left in the C stack is what we've got |
| 658 | return available - used; |
| 659 | } |
| 660 | // can start another coroutine, so limit ourselves to a coroutine stack size's worth |
| 661 | return COROUTINE_STACK_SIZE - used; |
| 662 | } |
| 663 | |
| 664 | |
| 665 | // This is used to avoid compiler warnings about returning the address of a local |
| 666 | static inline void *StopAddressWarnings(void *p) |
| 667 | { |
| 668 | return p; |
| 669 | } |
| 670 | |
| 671 | |
| 672 | void *Coroutine_GetStackHWM(void){ |
| 673 | assert(g_c.state == Coroutines_Active); |
| 674 | assert(Coroutine_StackHasNotOverrun()); |
| 675 | // Find where the guards end |
| 676 | unsigned char *guard; |
| 677 | for (guard = g_c.active->guard; Check_Guard(guard); guard += 4){ |
| 678 | // do nothing |
| 679 | } |
| 680 | return guard; |
| 681 | } |
| 682 | |
| 683 | |
| 684 | void Coroutine_ClearStackForHWM(void){ |
| 685 | assert(g_c.state == Coroutines_Active); |
| 686 | assert(Coroutine_StackHasNotOverrun()); |
| 687 | unsigned char *end = StackTopNow() - GUARD_PATTERN_SIZE; |
| 688 | for (unsigned char *guard = g_c.active->guard+GUARD_PATTERN_SIZE; guard <= end; guard += GUARD_PATTERN_SIZE){ |
| 689 | Apply_Guard(guard); |
| 690 | } |
| 691 | } |
| 692 | |
| 693 | |
| 694 | bool Coroutine_CanStartCoroutine(void){ |
| 695 | assert(g_c.state == Coroutines_Started || g_c.state == Coroutines_Active); |
| 696 | assert(Coroutine_StackHasNotOverrun()); |
| 697 | if (!List_IsEmpty(&g_c.free)){ |
| 698 | return true; |
| 699 | } |
| 700 | |
| 701 | return !g_c.stack_limit || g_c.stack_limit <= (unsigned char *)g_c.tip - 2*COROUTINE_STACK_SIZE; |
| 702 | } |
| 703 | |
| 704 | |
| 705 | void *Coroutine_GetCStackTop(void){ |
| 706 | assert(Coroutine_StackHasNotOverrun()); |
| 707 | if ((g_c.state == Coroutines_Started || g_c.state == Coroutines_Active) && g_c.tip != g_c.active) { |
| 708 | return g_c.tip->stack_top; |
| 709 | } else { |
| 710 | return StackTopNow(); |
| 711 | } |
| 712 | } |
| 713 | |
| 714 | |
| 715 | static unsigned char *StackTopNow(void){ |
| 716 | unsigned char here[4]; |
| 717 | return StopAddressWarnings(here); |
| 718 | } |
| 719 | |
| 720 | |
| 721 | struct Coroutine_ChainParam { |
| 722 | Coroutine_Start start; |
| 723 | void *value; |
| 724 | Coroutine *ret; |
| 725 | }; |
| 726 | |
| 727 | |
| 728 | static void *Coroutine_ChainFn( |
| 729 | void *param |
| 730 | ){ |
| 731 | struct Coroutine_ChainParam *params = (struct Coroutine_ChainParam *)param; |
| 732 | Coroutine_Continue(params->ret, params->start(params->value), true); |
| 733 | return NULL; |
| 734 | } |
| 735 | |
| 736 | |
| 737 | static void Coroutine_ChainYield( |
| 738 | void *unused |
| 739 | ){ |
| 740 | (void)unused; |
| 741 | } |
| 742 | |
| 743 | |
| 744 | void *Coroutine_Chain( |
| 745 | Coroutine_Start start, |
| 746 | void *value |
| 747 | ){ |
| 748 | assert(Check_Guard(Coroutine_GetActive()->guard)); |
| 749 | Coroutine *cor = Coroutine_New(Coroutine_ChainFn); |
| 750 | assert(cor); |
| 751 | struct Coroutine_ChainParam params = { |
| 752 | start, |
| 753 | value, |
| 754 | Coroutine_GetActive() |
| 755 | }; |
| 756 | Coroutine_Continue(cor, ¶ms, true); |
| 757 | void *res = Coroutine_Yield(NULL, Coroutine_ChainYield, NULL); |
| 758 | Coroutine_Delete(cor); |
| 759 | return res; |
| 760 | } |
| 761 | |
| 762 | |
| 763 | bool Coroutine_IsRunning( |
| 764 | Coroutine *cor |
| 765 | ) |
| 766 | { |
| 767 | int state = cor->state; |
| 768 | return state == Coroutine_Running || state == Coroutine_Waiting; |
| 769 | } |
| 770 | |
| 771 | |
| 772 | bool Coroutine_IsComplete( |
| 773 | Coroutine *cor |
| 774 | ) |
| 775 | { |
| 776 | int state = cor->state; |
| 777 | return state == Coroutine_Complete; |
| 778 | } |
| 779 | |
| 780 | |
| 781 | bool Coroutine_IsStarted(void){ |
| 782 | return g_c.state == Coroutines_Active || g_c.state == Coroutines_Started; |
| 783 | } |
| 784 | |