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Remove stack_per_coroutine
jonroach 18 Nov 2025 12:56
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9 months ago
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 #include "coroutine.h"
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 #include <assert.h>
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 #include <setjmp.h>
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 #include <stdbool.h>
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 #include <stddef.h>
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 #include "cor_platform.h"
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 // see CPython again, this time from ctypes.h
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 #if (defined (__SVR4) && defined (__sun)) || defined(COROUTINE_HAVE_ALLOCA_H)
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 # include <alloca.h>
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 #elif defined(MS_WIN32)
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 # include <malloc.h>
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 #endif
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 /* If the system does not define alloca(), we have to hope for a compiler builtin. */
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 #ifndef alloca
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 # if defined __GNUC__ || (__clang_major__ >= 4)
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 # define alloca __builtin_alloca
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 # else
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 # error "Could not define alloca() on your platform."
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 # endif
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 #endif
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 static void Coroutine_RunNext(void);
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 static void _Coroutine_Continue(Coroutine *cor, void *value, bool early);
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 static unsigned char *StackTopNow(void);
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 ///////////////////////////////////////////////////////////////////////////////
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 // 2-way linked lists...
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 //
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 // Brought inline here to avoid namespace polution
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 ///////////////////////////////////////////////////////////////////////////////
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34
 typedef struct List_Link List_Link;
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 struct List_Link {
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 List_Link *next;
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 List_Link *prev;
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 };
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40
 typedef struct List_Head List_Head;
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 struct List_Head {
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 union {
43
 struct {
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 List_Link link;
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 List_Link *filler;
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 } fwd;
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 struct {
48
 List_Link *filler;
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 List_Link link;
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 } back;
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 };
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 };
53
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55
 static inline bool List_IsEmpty(
56
 const List_Head *list
57
 ){
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58
 return list->fwd.link.next == &list->back.link;
59
 }
60
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62
 static inline List_Link *List_GetHead(
63
 const List_Head *list
64
 ){
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65
 return List_IsEmpty(list) ? NULL : list->fwd.link.next;
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 }
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68
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 // static inline List_Link *List_GetTail(
70
 // const List_Head *list
71
 // ){
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 // return List_IsEmpty(list) ? NULL : list->back.link.prev;
73
 // }
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75
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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
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80
 static inline void List_Init(
81
 List_Head *list
82
 ){
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83
 list->fwd.link.next = &list->back.link;
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 list->fwd.link.prev = NULL;
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 list->back.link.prev = &list->fwd.link;
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 }
87
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89
 static inline void List_AddHead(
90
 List_Head *list,
91
 List_Link *link
92
 ){
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93
 List_Link *first = list->fwd.link.next;
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 link->next = first;
95
 link->prev = &list->fwd.link;
96
 first->prev = link;
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 list->fwd.link.next = link;
98
 }
99
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101
 static inline void List_AddTail(
102
 List_Head *list,
103
 List_Link *link
104
 ){
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105
 List_Link *last = list->back.link.prev;
106
 link->prev = last;
107
 link->next = &list->back.link;
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 last->next = link;
109
 list->back.link.prev = link;
110
 }
111
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113
 static inline void List_Remove(
114
 List_Link *link
115
 ){
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116
 link->prev->next = link->next;
117
 link->next->prev = link->prev;
118
 }
119
120
 ///////////////////////////////////////////////////////////////////////////////
121
 // ...2-way linked lists
122
 ///////////////////////////////////////////////////////////////////////////////
123
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 typedef struct Coroutines Coroutines;
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125
126
 enum {
127
 Coroutines_Idle,
128
 Coroutines_Starting,
129
 Coroutines_Started,
130
 Coroutines_Active,
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 Coroutines_Stopping
132
 };
133
134
 enum {
135
 Chunk_Initial,
136
 Chunk_Create,
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 Chunk_Enter
138
 };
139
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 typedef enum Coroutine_State {
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141
 Coroutine_Free,
142
 Coroutine_Idle,
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 Coroutine_Running,
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 Coroutine_Waiting,
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 Coroutine_Complete
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 } Coroutine_State;
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147
148
 enum {
149
 Coroutines_Init,
150
 Coroutines_AllocatedChunk,
151
 Coroutines_CoroutineComplete,
152
 };
153
154
 struct Coroutine {
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 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
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 unsigned char *guard; // where the stack overrun guard is
159
 Coroutine_Start start; // entry point
160
 void *entry_param; // to pass to start
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 void *value; // yielded/returned
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 unsigned char *stack_top; // recorded at yield
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163
 Coroutine_State state;
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164
 };
165
166
 struct Coroutines {
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 _Cor_Mutex mutex;
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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
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171
172
 // singletons
173
 Coroutine *tip; // top of stack chunk
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 Coroutine *active; // currently running coroutine
175
 Coroutine *primary; // Coroutine_Run coroutine
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 unsigned char *stack_limit; // when not NULL, where the stack finishes
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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
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 _Cor_Mutex waiting_mutex;
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184
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 // Summary of the system
186
 Coroutine_Report report;
187
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188
 // state
189
 char state;
190
 };
191
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 _Cor_thread_local Coroutines g_c;
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193
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 static void stack_chunk_chunk(Coroutine *parent, size_t chunk_size);
195
 static void stack_chunk_base();
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196
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198
 #define GUARD_PATTERN_SIZE (4)
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 // Check whether the guard is intact
200
 static inline bool Check_Guard(
201
 unsigned char *guard
202
 ){
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 return !guard ||
204
 (guard[0] == 0xde &&
205
 guard[1] == 0xad &&
206
 guard[2] == 0xbe &&
207
 guard[3] == 0xef);
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 }
209
210
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 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
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 static bool Coroutine_StackHasNotOverrun(){
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
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 static void Coroutine_PrimeStackChunks(void)
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 {
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 unsigned char chunk_of_stack[COROUTINE_STARTUP_STACK_SIZE + GUARD_PATTERN_SIZE];
248
 Apply_Guard(chunk_of_stack);
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 assert(Check_Guard(chunk_of_stack));
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 // 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
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 g_c.guard = chunk_of_stack;
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 stack_chunk_base();
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 }
257
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259
 static void stack_chunk_chunk(
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 Coroutine *parent,
261
 size_t chunk_size
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 ){
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 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
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 Apply_Guard(chunk_of_stack);
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 #endif
271
 parent->guard = chunk_of_stack;
272
 stack_chunk_base();
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273
 }
274
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276
 static void stack_chunk_base(
277
 ){
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278
 Coroutine here;
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 here.state = Coroutine_Free;
280
 here.guard = NULL;
281
 here.coroutines = &g_c;
282
 List_AddHead(&g_c.free, &here.link);
283
 g_c.report.coroutines_pool_size += 1;
284
 g_c.tip = &here;
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285
 for(;;){
286
 switch (setjmp(here.buf)) {
287
 case Chunk_Initial:
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 if (here.state == Coroutine_Free){
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289
 // return to the coroutine allocator
290
 longjmp(g_c.chunk_allocated, 1);
291
 } else {
292
 assert(here.state == Coroutine_Complete);
293
 // we finish here to ensure the setjmp is redone
294
 if (g_c.primary == &here) {
295
 // if primary coroutine - return to Coroutine_Run
296
 longjmp(g_c.controller, Coroutines_CoroutineComplete);
297
 }
298
 _Cor_Mutex_Unlock(&g_c.mutex);
299
 Coroutine_RunNext();
300
 assert(false);
301
 }
302
 case Chunk_Create:
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 // Request to create a new chunk on the stack
304
 // We're here if the coroutine is:
305
 // Allocated, but not 'run' (Coroutine_Idle)
306
 // Run, but not not entered yet (Coroutine_Running)
307
 // Completed (Coroutine_Complete)
308
 assert(here.state == Coroutine_Idle || here.state == Coroutine_Running || here.state == Coroutine_Complete);
309
 unsigned char *ideal_limit = (unsigned char *)&here - COROUTINE_STACK_SIZE;
310
 stack_chunk_chunk(&here, StackTopNow() - ideal_limit);
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 assert(false);
312
 case Chunk_Enter:
313
 // request to start a coroutine (ie use the chunk for a coroutine)
314
 // arrive here with mutex locked
315
 assert(here.state == Coroutine_Running);
316
 g_c.active = &here;
317
 _Cor_Mutex_Unlock(&g_c.mutex);
318
 here.value = here.start(here.entry_param);
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319
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320
 // check the guard
321
 assert(Check_Guard(here.guard));
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322
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323
 _Cor_Mutex_Lock(&g_c.mutex);
324
 g_c.active = NULL;
325
 assert(here.state == Coroutine_Running);
326
 List_Remove(&here.link);
327
 here.state = Coroutine_Complete;
328
 List_AddTail(&g_c.inactive, &here.link);
329
 // Coroutine has completed
330
 // Loop round to redo the setjmp() - if this coroutine yielded, then the setjmp will
331
 // need reseting
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332
 }
333
 }
334
 }
335
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337
 static void Coroutine_RunNext(void)
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338
 {
339
 // arrive here with mutex unlocked
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 _Cor_Mutex_Lock(&g_c.waiting_mutex);
341
 _Cor_Mutex_Lock(&g_c.mutex);
342
 Coroutine *next = List_Link_Container(Coroutine, link, List_GetHead(&g_c.runable));
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 assert(next->state == Coroutine_Running);
344
 longjmp(next->buf, Chunk_Enter);
345
 assert(false);
346
 }
347
348
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349
 void Coroutine_StartSystem(void)
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350
 {
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351
 assert(g_c.state == Coroutines_Idle);
352
 g_c.state = Coroutines_Starting;
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354
 _Cor_Mutex_ctor(&g_c.mutex);
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8 months ago
356
 g_c.tip = NULL;
357
 g_c.active = NULL;
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359
 List_Init(&g_c.free);
360
 List_Init(&g_c.inactive);
361
 List_Init(&g_c.runable);
362
 List_Init(&g_c.waiting);
363
 _Cor_Mutex_ctor(&g_c.waiting_mutex);
364
 _Cor_Mutex_Lock(&g_c.waiting_mutex);
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 g_c.report.coroutines_created = 0;
367
 g_c.report.coroutines_pool_size = 0;
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368
369
 // prime the chunk system
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370
 if (!setjmp(g_c.chunk_allocated)){
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371
 Coroutine_PrimeStackChunks();
372
 assert(false);
373
 }
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374
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375
 assert(g_c.state == Coroutines_Starting);
376
 g_c.state = Coroutines_Started;
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377
 }
378
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379
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380
 void Coroutine_SetStackLimit(void *limit){
381
 assert(!limit || (unsigned char *)limit < (unsigned char *)g_c.tip);
382
 g_c.stack_limit = limit;
383
 }
384
385
8 months ago
386
 Coroutine_Report Coroutine_StopSystem(void)
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4
387
 {
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388
 _Cor_Mutex_Lock(&g_c.mutex);
389
 assert(g_c.state == Coroutines_Started);
390
 g_c.state = Coroutines_Stopping;
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4
391
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392
 uintptr_t stackminheadroom;;
393
 #if COROUTINE_RECORD_LOWEST_HEADROOM
394
 stackminheadroom = COROUTINE_STACK_SIZE;
8 months ago
395
 for (List_Link *link = g_c.free.fwd.link.next; link->next; link = link->next){
9 months ago
396
 Coroutine *cor = List_Link_Container(Coroutine, link, link);
7 months ago
397
 if (cor->guard){
398
 for (uintptr_t i = 4; i < COROUTINE_STACK_SIZE-3; i += 4){
399
 if (!Check_Guard(&cor->guard[i])){
400
 stackminheadroom = i < stackminheadroom ? i : stackminheadroom;
401
 break;
402
 }
9 months ago
403
 }
404
 }
405
 }
7 months ago
406
 #else
407
 stackminheadroom = 0;
408
 #endif
8 months ago
409
 g_c.report.lowest_headroom = stackminheadroom;
9 months ago
410
8 months ago
411
 assert(List_IsEmpty(&g_c.inactive));
412
 _Cor_Mutex_Unlock(&g_c.waiting_mutex);
413
 _Cor_Mutex_dtor(&g_c.waiting_mutex);
9 months ago
4
414
8 months ago
415
 assert(g_c.state == Coroutines_Stopping);
416
 g_c.state = Coroutines_Idle;
417
 _Cor_Mutex_Unlock(&g_c.mutex);
418
 _Cor_Mutex_dtor(&g_c.mutex);
9 months ago
419
8 months ago
420
 return g_c.report;
9 months ago
4
421
 }
422
9 months ago
423
9 months ago
424
 void Coroutine_Run_Coroutine(
425
 Coroutine *cor,
9 months ago
426
 void *value
427
 ){
428
 Coroutines *cors = cor->coroutines;
8 months ago
429
 assert(&g_c == cors);
8 months ago
430
 _Cor_Mutex_Lock(&cors->mutex);
9 months ago
431
 assert(cors->state == Coroutines_Started);
432
 cors->state = Coroutines_Active;
433
 cors->primary = cor;
9 months ago
434
8 months ago
435
 _Coroutine_Continue(cor, value, true);
9 months ago
4
436
9 months ago
437
 if (!setjmp(cors->controller)){
8 months ago
438
 _Cor_Mutex_Unlock(&cors->mutex);
9 months ago
439
440
 // check the guard
8 months ago
441
 assert(Check_Guard(cors->guard));
9 months ago
442
9 months ago
4
443
 // start the first coroutine
444
 Coroutine_RunNext();
445
 }
9 months ago
446
 // arrive here with mutex locked
9 months ago
447
 assert(List_IsEmpty(&cors->runable));
448
 assert(List_IsEmpty(&cors->waiting));
449
 assert(cors->state == Coroutines_Active);
450
 cors->state = Coroutines_Started;
8 months ago
451
 _Cor_Mutex_Unlock(&cors->mutex);
9 months ago
452
 }
453
454
455
 void *Coroutine_Run(
456
 Coroutine_Start start,
457
 void *value
458
 ){
7 months ago
459
 if (g_c.active){
460
 return start(value);
461
 }
462
 assert(g_c.state == Coroutines_Idle || g_c.state == Coroutines_Started);
463
 bool need_start = g_c.state == Coroutines_Idle;
464
 if (need_start){
465
 Coroutine_StartSystem();
466
 }
9 months ago
467
 Coroutine *cor = Coroutine_New(start);
468
 Coroutine_Run_Coroutine(cor, value);
9 months ago
469
 void *res = Coroutine_GetValue(cor);
470
 Coroutine_Delete(cor);
7 months ago
471
 if (need_start){
472
 Coroutine_StopSystem();
473
 }
9 months ago
474
 return res;
9 months ago
4
475
 }
476
477
9 months ago
478
 Coroutine *Coroutine_New(
479
 Coroutine_Start start
480
 ){
8 months ago
481
 assert((g_c.state == Coroutines_Started && List_IsEmpty(&g_c.inactive)) || g_c.state == Coroutines_Active);
7 months ago
482
 assert(Coroutine_StackHasNotOverrun());
483
 assert(Coroutine_CanStartCoroutine());
9 months ago
484
9 months ago
4
485
 // if none free - add one
8 months ago
486
 if (List_IsEmpty(&g_c.free)){
7 months ago
487
 Coroutine *tip = g_c.tip;
7 months ago
488
 Coroutine *me = g_c.active;
489
 if (tip == me) {
490
 if (!setjmp(g_c.chunk_allocated)){
491
 unsigned char *ideal_limit = (unsigned char *)me - COROUTINE_STACK_SIZE;
492
 stack_chunk_chunk(me, StackTopNow() - ideal_limit);
493
 }
494
 } else {
495
 if (!setjmp(g_c.chunk_allocated)){
496
 longjmp(tip->buf, Chunk_Create);
497
 }
9 months ago
4
498
 }
499
 }
500
8 months ago
501
 Coroutine *cor = List_Link_Container(Coroutine, link, List_GetHead(&g_c.free));
9 months ago
4
502
 assert(cor->state == Coroutine_Free);
503
 cor->state = Coroutine_Idle;
504
 cor->start = start;
505
 cor->value = NULL;
506
 List_Remove(&cor->link);
8 months ago
507
 List_AddHead(&g_c.inactive, &cor->link);
9 months ago
4
508
8 months ago
509
 g_c.report.coroutines_created += 1;
9 months ago
510
9 months ago
4
511
 return cor;
512
 }
513
9 months ago
514
515
 void Coroutine_Delete(
516
 Coroutine *cor
517
 ){
7 months ago
518
 assert(Coroutine_StackHasNotOverrun());
9 months ago
519
 Coroutines *cors = cor->coroutines;
8 months ago
520
 _Cor_Mutex_Lock(&cors->mutex);
9 months ago
4
521
 assert(cor->state == Coroutine_Idle || cor->state == Coroutine_Complete);
522
 cor->state = Coroutine_Free;
523
 List_Remove(&cor->link);
9 months ago
524
 List_AddTail(&cors->free, &cor->link);
8 months ago
525
 _Cor_Mutex_Unlock(&cors->mutex);
9 months ago
4
526
 }
527
9 months ago
528
8 months ago
529
 // Coroutine_Continue, assuming the mutex is claimed
530
 static void _Coroutine_Continue(
9 months ago
531
 Coroutine *cor,
532
 void *value,
533
 bool early
534
 ){
535
 Coroutines *cors = cor->coroutines;
9 months ago
4
536
 assert(cor->state == Coroutine_Idle || cor->state == Coroutine_Waiting);
537
 cor->entry_param = value;
538
 cor->state = Coroutine_Running;
539
 List_Remove(&cor->link);
540
 if ( early ) {
9 months ago
541
 List_AddHead(&cors->runable, &cor->link);
9 months ago
4
542
 } else {
9 months ago
543
 List_AddTail(&cors->runable, &cor->link);
9 months ago
4
544
 }
8 months ago
545
 _Cor_Mutex_Unlock(&cors->waiting_mutex);
8 months ago
546
 }
547
548
549
 void Coroutine_Continue(
550
 Coroutine *cor,
551
 void *value,
552
 bool early
553
 ){
7 months ago
554
 assert(Coroutine_StackHasNotOverrun());
8 months ago
555
 Coroutines *cors = cor->coroutines;
8 months ago
556
 _Cor_Mutex_Lock(&cors->mutex);
8 months ago
557
 _Coroutine_Continue(cor, value, early);
8 months ago
558
 _Cor_Mutex_Unlock(&cors->mutex);
9 months ago
4
559
 }
560
9 months ago
561
562
 void *Coroutine_Yield(
563
 void *value,
564
 Coroutine_YieldCallback on_yield,
9 months ago
565
 void *yield_me
9 months ago
566
 ){
8 months ago
567
 Coroutine *me = g_c.active;
7 months ago
568
 assert(me);
569
 assert(Coroutine_StackHasNotOverrun());
9 months ago
570
8 months ago
571
 _Cor_Mutex_Lock(&g_c.mutex);
9 months ago
572
 Coroutines *cors = me->coroutines;
8 months ago
573
 assert(me && me->state == Coroutine_Running && cors == &g_c);
7 months ago
574
 me->stack_top = StackTopNow();
9 months ago
4
575
 me->value = value;
576
 me->state = Coroutine_Waiting;
9 months ago
577
9 months ago
4
578
 List_Remove(&me->link);
8 months ago
579
 if (!List_IsEmpty(&cors->runable)){
8 months ago
580
 _Cor_Mutex_Unlock(&cors->waiting_mutex);
8 months ago
581
 }
9 months ago
582
 List_AddTail(&cors->waiting, &me->link);
9 months ago
583
9 months ago
584
 switch (setjmp(me->buf)){
585
 case Chunk_Initial:
8 months ago
586
 _Cor_Mutex_Unlock(&cors->mutex);
9 months ago
587
 on_yield(yield_me);
9 months ago
4
588
 Coroutine_RunNext();
7 months ago
589
 assert(false);
9 months ago
590
 case Chunk_Create:
7 months ago
591
 assert(me == g_c.tip);
592
 unsigned char *ideal_limit = (unsigned char *)me - COROUTINE_STACK_SIZE;
593
 stack_chunk_chunk(me, me->stack_top - ideal_limit);
9 months ago
594
 assert(false);
595
 case Chunk_Enter:
596
 // arrive here with mutex locked
9 months ago
597
 cors->active = me;
7 months ago
598
 assert(Coroutine_StackHasNotOverrun());
9 months ago
599
 // when we return here - we are running again
600
 assert(me->state == Coroutine_Running);
601
 void *res = me->entry_param;
8 months ago
602
 _Cor_Mutex_Unlock(&cors->mutex);
9 months ago
603
 return res;
9 months ago
4
604
 }
9 months ago
605
 return NULL;
9 months ago
4
606
 }
607
9 months ago
608
609
 void *Coroutine_GetValue(
610
 Coroutine *cor
611
 ){
9 months ago
4
612
 return cor->value;
613
 }
614
9 months ago
615
8 months ago
616
 Coroutine *Coroutine_GetActive(void)
9 months ago
4
617
 {
8 months ago
618
 return g_c.active;
9 months ago
4
619
 }
620
9 months ago
621
8 months ago
622
 intptr_t Coroutine_GetStackHeadroom(void){
7 months ago
623
 assert(Coroutine_StackHasNotOverrun());
624
 Coroutine *me = g_c.active;
625
 if (!me){
626
 // no active coroutine
627
 unsigned char *stack_limit = g_c.stack_limit;
628
 if (stack_limit){
629
 // no stack limit - assume we'll use COROUTINE_STACK_SIZE
630
 return StackTopNow() - stack_limit;
631
 } else {
632
 // no information where the stack ends - return something
633
 return COROUTINE_STACK_SIZE;
634
 }
635
 }
636
 unsigned char *stack_top = StackTopNow();
637
 if (me->guard){
638
 // guard established - that's where we'll measure to
639
 return stack_top - me->guard;
640
 }
641
 intptr_t used = (unsigned char *)me - stack_top;
642
 unsigned char *stack_limit = g_c.stack_limit;
643
 if (!stack_limit){
644
 // no stack limit - assume we'll use COROUTINE_STACK_SIZE
645
 return COROUTINE_STACK_SIZE - used;
646
 }
647
 intptr_t available = (unsigned char *)me - stack_limit;
648
 if (available < 2*COROUTINE_STACK_SIZE){
649
 // can't start another coroutine, so whatever's left in the C stack is what we've got
650
 return available - used;
651
 }
652
 // can start another coroutine, so limit ourselves to a coroutine stack size's worth
653
 return COROUTINE_STACK_SIZE - used;
9 months ago
654
 }
655
656
7 months ago
657
 // This is used to avoid compiler warnings about returning the address of a local
658
 static inline void *StopAddressWarnings(void *p)
659
 {
660
 return p;
9 months ago
661
 }
662
663
7 months ago
664
 void *Coroutine_GetStackHWM(void){
665
 assert(g_c.state == Coroutines_Active);
7 months ago
666
 assert(Coroutine_StackHasNotOverrun());
7 months ago
667
 // Find where the guards end
668
 unsigned char *guard;
669
 for (guard = g_c.active->guard; Check_Guard(guard); guard += 4){
670
 // do nothing
671
 }
672
 return guard;
673
 }
8 months ago
674
675
7 months ago
676
 void Coroutine_ClearStackForHWM(void){
677
 assert(g_c.state == Coroutines_Active);
7 months ago
678
 assert(Coroutine_StackHasNotOverrun());
7 months ago
679
 unsigned char *end = StackTopNow() - GUARD_PATTERN_SIZE;
680
 for (unsigned char *guard = g_c.active->guard+GUARD_PATTERN_SIZE; guard <= end; guard += GUARD_PATTERN_SIZE){
681
 Apply_Guard(guard);
7 months ago
682
 }
683
 }
684
685
7 months ago
686
 bool Coroutine_CanStartCoroutine(){
687
 assert(g_c.state == Coroutines_Started || g_c.state == Coroutines_Active);
688
 assert(Coroutine_StackHasNotOverrun());
7 months ago
689
 if (!List_IsEmpty(&g_c.free)){
690
 return true;
691
 }
7 months ago
692
693
 return !g_c.stack_limit || g_c.stack_limit <= (unsigned char *)g_c.tip - 2*COROUTINE_STACK_SIZE;
7 months ago
694
 }
695
696
8 months ago
697
 void *Coroutine_GetCStackTop(void){
7 months ago
698
 assert(Coroutine_StackHasNotOverrun());
699
 if ((g_c.state == Coroutines_Started || g_c.state == Coroutines_Active) && g_c.tip != g_c.active) {
700
 return g_c.tip->stack_top;
701
 } else {
702
 return StackTopNow();
703
 }
9 months ago
704
 }
705
706
7 months ago
707
 static unsigned char *StackTopNow(void){
7 months ago
708
 unsigned char here[4];
709
 return StopAddressWarnings(here);
710
 }
711
712
9 months ago
713
 struct Coroutine_ChainParam {
714
 Coroutine_Start start;
715
 void *value;
716
 Coroutine *ret;
717
 };
718
719
720
 static void *Coroutine_ChainFn(
721
 void *param
722
 ){
723
 struct Coroutine_ChainParam *params = (struct Coroutine_ChainParam *)param;
724
 Coroutine_Continue(params->ret, params->start(params->value), true);
725
 return NULL;
726
 }
727
728
729
 static void Coroutine_ChainYield(
730
 void *unused
731
 ){
732
 (void)unused;
733
 }
734
735
736
 void *Coroutine_Chain(
737
 Coroutine_Start start,
738
 void *value
739
 ){
8 months ago
740
 assert(Check_Guard(Coroutine_GetActive()->guard));
9 months ago
741
 Coroutine *cor = Coroutine_New(Coroutine_ChainFn);
742
 struct Coroutine_ChainParam params = {
743
 start,
744
 value,
745
 Coroutine_GetActive()
746
 };
747
 Coroutine_Continue(cor, &params, true);
748
 void *res = Coroutine_Yield(NULL, Coroutine_ChainYield, NULL);
749
 Coroutine_Delete(cor);
750
 return res;
751
 }
752
753
9 months ago
754
 bool Coroutine_IsRunning(
755
 Coroutine *cor
756
 )
9 months ago
4
757
 {
9 months ago
758
 int state = cor->state;
759
 return state == Coroutine_Running || state == Coroutine_Waiting;
9 months ago
4
760
 }
9 months ago
761
762
8 months ago
763
 bool Coroutine_IsStarted(void){
8 months ago
764
 return g_c.state == Coroutines_Active || g_c.state == Coroutines_Started;
9 months ago
765
 }
766