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Fix assertion when setting stack limit
jonroach 29 Dec 2025 16:41
1 contributor
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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 <stdio.h>
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 #include "cor_platform.h"
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8
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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
24
8 months ago
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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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29
 ///////////////////////////////////////////////////////////////////////////////
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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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33
 ///////////////////////////////////////////////////////////////////////////////
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 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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 };
40
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 typedef struct List_Head List_Head;
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 struct List_Head {
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 union {
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 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 {
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 List_Link *filler;
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 List_Link link;
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 } back;
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 };
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 };
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56
 static inline bool List_IsEmpty(
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 const List_Head *list
58
 ){
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4
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 return list->fwd.link.next == &list->back.link;
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 }
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63
 static inline List_Link *List_GetHead(
64
 const List_Head *list
65
 ){
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4
66
 return List_IsEmpty(list) ? NULL : list->fwd.link.next;
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 }
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69
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 static inline List_Link *List_Begin(
71
 const List_Head *list
72
 ){
73
 return list->fwd.link.next;
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 }
75
76
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 static inline bool Link_NextIsLink(
78
 const List_Link *link
79
 ){
80
 return link->next != NULL;
81
 }
82
83
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 static inline List_Link *Link_Next(
85
 List_Link *link
86
 ){
87
 return link->next;
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 }
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90
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 static inline bool Link_PrevIsLink(
92
 const List_Link *link
93
 ){
94
 return link->prev != NULL;
95
 }
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97
98
 static inline List_Link *Link_Prev(
99
 List_Link *link
100
 ){
101
 return link->prev;
102
 }
103
6 months ago
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 static inline List_Link *List_GetTail(
105
 const List_Head *list
106
 ){
107
 return List_IsEmpty(list) ? NULL : list->back.link.prev;
108
 }
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110
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4
111
 #define OFFSETOF(Container, Field) ((char *)&((Container *)4)->Field - (char *)(Container *)4)
112
 #define List_Link_Container(Container, Link, link) ((Container *)((char *)(link) - OFFSETOF(Container, Link)))
113
9 months ago
114
115
 static inline void List_Init(
116
 List_Head *list
117
 ){
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4
118
 list->fwd.link.next = &list->back.link;
119
 list->fwd.link.prev = NULL;
120
 list->back.link.prev = &list->fwd.link;
121
 }
122
9 months ago
123
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124
 static inline void Link_AddAfter(
125
 List_Link *link,
126
 List_Link *after
127
 ){
128
 link->next = after->next;
129
 link->prev = after;
130
 after->next->prev = link;
131
 after->next = link;
132
 }
133
134
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135
 static inline void List_AddHead(
136
 List_Head *list,
137
 List_Link *link
138
 ){
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139
 Link_AddAfter(link, &list->fwd.link);
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4
140
 }
141
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142
6 months ago
143
 static inline void Link_AddBefore(
144
 List_Link *link,
145
 List_Link *before
146
 ){
147
 link->prev = before->prev;
148
 link->next = before;
149
 before->prev->next = link;
150
 before->prev = link;
151
 }
152
153
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 static inline void List_AddTail(
155
 List_Head *list,
156
 List_Link *link
157
 ){
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158
 Link_AddBefore(link, &list->back.link);
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4
159
 }
160
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6 months ago
162
 static inline void Link_Remove(
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 List_Link *link
164
 ){
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165
 link->prev->next = link->next;
166
 link->next->prev = link->prev;
167
 }
168
169
 ///////////////////////////////////////////////////////////////////////////////
170
 // ...2-way linked lists
171
 ///////////////////////////////////////////////////////////////////////////////
172
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 typedef struct Coroutines Coroutines;
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174
175
 enum {
176
 Coroutines_Starting,
177
 Coroutines_Started,
178
 Coroutines_Active,
179
 Coroutines_Stopping
180
 };
181
182
 enum {
183
 Chunk_Initial,
184
 Chunk_Create,
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 Chunk_Split,
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186
 Chunk_Enter
187
 };
188
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 typedef enum Coroutine_State {
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190
 Coroutine_Free,
191
 Coroutine_Idle,
192
 Coroutine_Running,
193
 Coroutine_Waiting,
194
 Coroutine_Complete
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 } Coroutine_State;
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196
197
 enum {
198
 Coroutines_Init,
199
 Coroutines_AllocatedChunk,
200
 Coroutines_CoroutineComplete,
201
 };
202
203
 struct Coroutine {
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 Coroutines *coroutines; // so can work with it off-thread
205
 List_Link link; // for whichever list it's on
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 List_Link all_link; // list of all Coroutines
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 jmp_buf buf; // how to get back to it
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208
 unsigned char *prev_limit; // the previous Coroutine's stack limit
209
 unsigned char *base; // where the base (high address) of this Coroutine's stack is
210
 unsigned char *limit; // where the limit (low address) of this Coroutine's stack is
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 unsigned char *guard; // where the stack overrun guard is
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 size_t size;
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 Coroutine_Start start; // entry point
214
 void *entry_param; // to pass to start
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 void *value; // yielded/returned
216
 unsigned char *stack_top; // recorded at yield
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 Coroutine_State state;
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218
 };
219
220
 struct Coroutines {
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 _Cor_Mutex mutex;
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 jmp_buf controller; // to return from Coroutine_Run
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 jmp_buf chunk_allocated;// for chunk allocation
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 unsigned char *guard; // the stack guard for the startup sequence
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 size_t gap_before; // bytes between previous's stack_top and next's Coroutine
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 size_t gap_after; // bytes between Coroutine and stack_base
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228
 // singletons
229
 Coroutine *tip; // top of stack chunk
230
 Coroutine *active; // currently running coroutine
231
 Coroutine *primary; // Coroutine_Run coroutine
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 unsigned char *stack_limit; // when not NULL, where the stack finishes
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233
234
 // lists
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 List_Head all; // all Coroutines (in address order)
236
 List_Head free; // free Coroutines
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 List_Head inactive; // idle or complete
238
 List_Head runable; // running or waiting to run
239
 List_Head waiting; // yielded / waiting to run
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 _Cor_Mutex waiting_mutex;
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241
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 // Summary of the system
243
 Coroutine_Report report;
244
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 // state
246
 char state;
247
 };
248
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 _Cor_thread_local Coroutines *g_c;
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 static void ReserveStackSpace(Coroutines *cors, Coroutine *parent, size_t chunk_size, unsigned char *childs_limit);
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 static void stack_chunk_base(Coroutines *cors, Coroutine *parent, unsigned char *prev_limit, unsigned char *limit);
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 #define GUARD_PATTERN_SIZE (4)
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 // Check whether the guard is intact
257
 static inline bool Check_Guard(
258
 unsigned char *guard
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 ){
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 return !guard ||
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 (guard[0] == 0xde &&
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 guard[1] == 0xad &&
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 guard[2] == 0xbe &&
264
 guard[3] == 0xef);
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 }
266
267
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 static inline void Apply_Guard(unsigned char *guard){
269
 guard[0] = 0xde;
270
 guard[1] = 0xad;
271
 guard[2] = 0xbe;
272
 guard[3] = 0xef;
273
 }
274
275
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 static bool Coroutine_StackHasOverrun(void){
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 unsigned char *stack_top = StackTopNow();
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 unsigned char *stack_limit = g_c ? g_c->stack_limit : NULL;
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279
 if (stack_limit && stack_top < stack_limit){
280
 // current stack top is beyond limit - we are overrunning NOW
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 return true;
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282
 }
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283
 Coroutine *me = g_c ? g_c->active : NULL;
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284
 if (!me){
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285
 return false;
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286
 }
287
 if (me->guard){
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 return !Check_Guard(me->guard);
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289
 }
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 return stack_top < me->limit;
7 months ago
291
 }
292
293
6 months ago
294
 static void ReserveStackSpace(
295
 Coroutines *cors,
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296
 Coroutine *parent,
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297
 size_t chunk_size,
298
 unsigned char *childs_limit
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 ){
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300
 unsigned char *chunk_of_stack = alloca(chunk_size);
301
 #if COROUTINE_RECORD_LOWEST_HEADROOM
302
 for (size_t i = 0; i <= chunk_size-GUARD_PATTERN_SIZE; i += GUARD_PATTERN_SIZE){
303
 Apply_Guard(&chunk_of_stack[i]);
304
 }
305
 #else
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306
 Apply_Guard(chunk_of_stack);
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307
 #endif
6 months ago
308
 if (parent){
309
 parent->guard = chunk_of_stack;
310
 parent->limit = chunk_of_stack;
311
 parent->base = chunk_of_stack + chunk_size;
312
 }
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313
 stack_chunk_base(cors, parent, chunk_of_stack, childs_limit);
9 months ago
4
314
 }
315
9 months ago
316
317
 static void stack_chunk_base(
6 months ago
318
 Coroutines *cors,
6 months ago
319
 Coroutine *parent,
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320
 unsigned char *prev_limit,
321
 unsigned char *limit
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322
 ){
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323
 Coroutine here;
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324
 here.coroutines = cors;
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325
 here.state = Coroutine_Free;
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326
 here.prev_limit = prev_limit;
327
 here.size = 0;
328
 here.base = NULL;
329
 here.guard = limit;
330
 here.limit = limit;
331
 if (limit){
332
 here.base = (unsigned char *)&here - cors->gap_after;
333
 here.size = here.base - here.limit;
334
 Apply_Guard(limit);
335
 }
336
6 months ago
337
 // insert into all list
338
 if (parent){
339
 Link_AddAfter(&here.all_link, &parent->all_link);
340
 } else {
341
 List_AddHead(&cors->all, &here.all_link);
6 months ago
342
 }
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343
 // add to free list
344
 List_AddTail(&cors->free, &here.link);
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345
346
 cors->report.coroutines_pool_size += 1;
347
348
 if (!cors->tip || &here < cors->tip){
349
 cors->tip = &here;
350
 }
351
7 months ago
352
 for(;;){
353
 switch (setjmp(here.buf)) {
354
 case Chunk_Initial:
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355
 if (here.state == Coroutine_Free){
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356
 // return to the coroutine allocator
6 months ago
357
 longjmp(cors->chunk_allocated, 1);
7 months ago
358
 } else {
359
 assert(here.state == Coroutine_Complete);
360
 // we finish here to ensure the setjmp is redone
6 months ago
361
 if (cors->primary == &here) {
7 months ago
362
 // if primary coroutine - return to Coroutine_Run
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363
 longjmp(cors->controller, Coroutines_CoroutineComplete);
7 months ago
364
 }
6 months ago
365
 _Cor_Mutex_Unlock(&cors->mutex);
7 months ago
366
 Coroutine_RunNext();
367
 assert(false);
368
 }
369
 case Chunk_Create:
7 months ago
370
 // Request to create a new chunk on the stack
371
 // We're here if the coroutine is:
372
 // Allocated, but not 'run' (Coroutine_Idle)
373
 // Run, but not not entered yet (Coroutine_Running)
374
 // Completed (Coroutine_Complete)
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375
 // Free, and the coroutines system is starting - we're characterising the system
376
 assert(here.state == Coroutine_Idle ||
377
 here.state == Coroutine_Running ||
378
 here.state == Coroutine_Complete ||
379
 (here.state == Coroutine_Free && cors->state == Coroutines_Starting));
380
 ReserveStackSpace(here.coroutines, &here, here.size, NULL);
7 months ago
381
 assert(false);
6 months ago
382
 case Chunk_Split:
383
 // Request to split this free block into two
384
 // here.size will be set to our shorter size
385
 ReserveStackSpace(here.coroutines, &here, here.size, here.limit);
386
 assert(false);
7 months ago
387
 case Chunk_Enter:
388
 // request to start a coroutine (ie use the chunk for a coroutine)
389
 // arrive here with mutex locked
390
 assert(here.state == Coroutine_Running);
6 months ago
391
 here.coroutines->active = &here;
392
 _Cor_Mutex_Unlock(&cors->mutex);
7 months ago
393
 here.value = here.start(here.entry_param);
9 months ago
394
7 months ago
395
 // check the guard
396
 assert(Check_Guard(here.guard));
9 months ago
397
6 months ago
398
 _Cor_Mutex_Lock(&here.coroutines->mutex);
399
 here.coroutines->active = NULL;
7 months ago
400
 assert(here.state == Coroutine_Running);
6 months ago
401
 Link_Remove(&here.link);
7 months ago
402
 here.state = Coroutine_Complete;
6 months ago
403
 List_AddTail(&here.coroutines->inactive, &here.link);
7 months ago
404
 // Coroutine has completed
405
 // Loop round to redo the setjmp() - if this coroutine yielded, then the setjmp will
406
 // need reseting
9 months ago
4
407
 }
408
 }
409
 }
410
9 months ago
411
8 months ago
412
 static void Coroutine_RunNext(void)
9 months ago
413
 {
414
 // arrive here with mutex unlocked
6 months ago
415
 _Cor_Mutex_Lock(&g_c->waiting_mutex);
416
 _Cor_Mutex_Lock(&g_c->mutex);
417
 Coroutine *next = List_Link_Container(Coroutine, link, List_GetHead(&g_c->runable));
9 months ago
418
 assert(next->state == Coroutine_Running);
419
 longjmp(next->buf, Chunk_Enter);
420
 assert(false);
421
 }
422
423
8 months ago
424
 void Coroutine_StartSystem(void)
9 months ago
4
425
 {
6 months ago
426
 assert(!g_c);
9 months ago
427
6 months ago
428
 Coroutines *cors = _Cor_Malloc(sizeof(*g_c));
429
 assert(cors);
9 months ago
430
6 months ago
431
 cors->state = Coroutines_Starting;
432
 _Cor_Mutex_ctor(&cors->mutex);
9 months ago
433
6 months ago
434
 cors->tip = NULL;
435
 cors->active = NULL;
9 months ago
4
436
6 months ago
437
 List_Init(&cors->all);
6 months ago
438
 List_Init(&cors->free);
439
 List_Init(&cors->inactive);
440
 List_Init(&cors->runable);
441
 List_Init(&cors->waiting);
442
 _Cor_Mutex_ctor(&cors->waiting_mutex);
443
 _Cor_Mutex_Lock(&cors->waiting_mutex);
9 months ago
4
444
6 months ago
445
 cors->report.coroutines_created = 0;
446
 cors->report.coroutines_pool_size = 0;
447
 cors->report.largest_stack = 0;
448
449
 // Charactersize the system...
450
 if (!setjmp(cors->chunk_allocated)){
451
 ReserveStackSpace(cors, NULL, COROUTINE_STARTUP_STACK_SIZE, NULL);
9 months ago
4
452
 }
6 months ago
453
 Coroutine *cor = List_Link_Container(Coroutine, link, List_GetHead(&cors->free));
454
 cor->size = COROUTINE_STARTUP_STACK_SIZE;
455
 if (!setjmp(cors->chunk_allocated)){
456
 longjmp(cor->buf, Chunk_Create);
457
 }
458
 cors->gap_before = cor->prev_limit - (unsigned char *)cor;
459
 cors->gap_after = (unsigned char *)cor - cor->base;
460
 // ...charactersize the system
9 months ago
461
6 months ago
462
 // discard what we've just created
6 months ago
463
 List_Init(&cors->all);
6 months ago
464
 List_Init(&cors->free);
465
 cors->tip = NULL;
466
467
 cors->state = Coroutines_Started;
468
469
 g_c = cors;
9 months ago
4
470
 }
471
9 months ago
472
7 months ago
473
 void Coroutine_SetStackLimit(void *limit){
6 months ago
474
 assert(g_c);
6 months ago
475
 assert(!limit || !(g_c->state == Coroutines_Started || g_c->state == Coroutines_Active) || (unsigned char *)limit < (unsigned char *)g_c->tip || !g_c->tip);
6 months ago
476
 g_c->stack_limit = limit;
7 months ago
477
 }
478
479
8 months ago
480
 Coroutine_Report Coroutine_StopSystem(void)
9 months ago
4
481
 {
6 months ago
482
 assert(g_c);
483
 assert(g_c->state == Coroutines_Started);
484
 _Cor_Mutex_Lock(&g_c->mutex);
485
 g_c->state = Coroutines_Stopping;
9 months ago
4
486
6 months ago
487
 uintptr_t stackminheadroom;
7 months ago
488
 #if COROUTINE_RECORD_LOWEST_HEADROOM
6 months ago
489
 stackminheadroom = g_c->report.largest_stack;
490
 for (List_Link *link = g_c->free.fwd.link.next; Link_NextIsLink(link); link = Link_Next(link)){
9 months ago
491
 Coroutine *cor = List_Link_Container(Coroutine, link, link);
7 months ago
492
 if (cor->guard){
6 months ago
493
 for (uintptr_t i = 4; i < cor->size-3; i += 4){
7 months ago
494
 if (!Check_Guard(&cor->guard[i])){
495
 stackminheadroom = i < stackminheadroom ? i : stackminheadroom;
496
 break;
497
 }
9 months ago
498
 }
499
 }
500
 }
7 months ago
501
 #else
502
 stackminheadroom = 0;
503
 #endif
6 months ago
504
 g_c->report.lowest_headroom = stackminheadroom;
9 months ago
505
6 months ago
506
 assert(List_IsEmpty(&g_c->inactive));
507
 _Cor_Mutex_Unlock(&g_c->waiting_mutex);
508
 _Cor_Mutex_dtor(&g_c->waiting_mutex);
9 months ago
4
509
6 months ago
510
 assert(g_c->state == Coroutines_Stopping);
511
 _Cor_Mutex_Unlock(&g_c->mutex);
512
 _Cor_Mutex_dtor(&g_c->mutex);
9 months ago
513
6 months ago
514
 Coroutine_Report ret = g_c->report;
515
516
 _Cor_Free(g_c);
517
 g_c = NULL;
518
519
 return ret;
9 months ago
4
520
 }
521
9 months ago
522
9 months ago
523
 void Coroutine_Run_Coroutine(
524
 Coroutine *cor,
9 months ago
525
 void *value
526
 ){
527
 Coroutines *cors = cor->coroutines;
6 months ago
528
529
 // Can't Coroutine_Run_Coroutine() off-thread
530
 assert(g_c == cors);
531
8 months ago
532
 _Cor_Mutex_Lock(&cors->mutex);
9 months ago
533
 assert(cors->state == Coroutines_Started);
534
 cors->state = Coroutines_Active;
535
 cors->primary = cor;
9 months ago
536
8 months ago
537
 _Coroutine_Continue(cor, value, true);
9 months ago
4
538
9 months ago
539
 if (!setjmp(cors->controller)){
8 months ago
540
 _Cor_Mutex_Unlock(&cors->mutex);
9 months ago
541
542
 // check the guard
8 months ago
543
 assert(Check_Guard(cors->guard));
9 months ago
544
9 months ago
4
545
 // start the first coroutine
546
 Coroutine_RunNext();
547
 }
9 months ago
548
 // arrive here with mutex locked
9 months ago
549
 assert(List_IsEmpty(&cors->runable));
550
 assert(List_IsEmpty(&cors->waiting));
551
 assert(cors->state == Coroutines_Active);
552
 cors->state = Coroutines_Started;
8 months ago
553
 _Cor_Mutex_Unlock(&cors->mutex);
9 months ago
554
 }
555
556
6 months ago
557
 bool Coroutine_Run(
6 months ago
558
 size_t stack,
9 months ago
559
 Coroutine_Start start,
6 months ago
560
 void *value,
561
 void **result
9 months ago
562
 ){
6 months ago
563
 if (g_c && g_c->active){
6 months ago
564
 void *res = start(value);
565
 if (result){
566
 *result = res;
567
 }
568
 // no failures, so...
569
 return false;
7 months ago
570
 }
6 months ago
571
 assert(!g_c || g_c->state == Coroutines_Started);
572
 bool need_start = !g_c;
7 months ago
573
 if (need_start){
574
 Coroutine_StartSystem();
575
 }
6 months ago
576
 Coroutine *cor = Coroutine_New(stack, start);
6 months ago
577
 if (!cor){
578
 // that didn't work
579
 return true;
580
 }
9 months ago
581
 Coroutine_Run_Coroutine(cor, value);
6 months ago
582
 if (result){
583
 *result = Coroutine_GetValue(cor);
584
 }
9 months ago
585
 Coroutine_Delete(cor);
7 months ago
586
 if (need_start){
587
 Coroutine_StopSystem();
588
 }
6 months ago
589
 // no failures, so...
590
 return false;
9 months ago
4
591
 }
592
593
6 months ago
594
 static void Coroutine_FreeToIdle(
595
 Coroutine *cor,
9 months ago
596
 Coroutine_Start start
597
 ){
6 months ago
598
 assert(cor->state == Coroutine_Free);
599
 cor->state = Coroutine_Idle;
600
 cor->start = start;
601
 cor->value = NULL;
602
 Link_Remove(&cor->link);
603
 List_AddHead(&g_c->inactive, &cor->link);
9 months ago
604
6 months ago
605
 g_c->report.coroutines_created += 1;
606
 }
607
608
609
 static void Coroutine_FreeToIdleSize(
610
 Coroutine *cor,
611
 Coroutine_Start start,
612
 size_t size
613
 ){
614
 assert(!cor->guard);
615
 cor->size = size;
616
 cor->base = (unsigned char *)cor - g_c->gap_after;
617
 cor->limit = cor->base - cor->size;
618
 Coroutine_FreeToIdle(cor, start);
619
 }
620
621
622
 static Coroutine *Coroutine_New_Lock_Assumed(
623
 size_t size,
624
 Coroutine_Start start
625
 ){
626
 List_Link *link;
627
628
 if (!g_c->tip){
629
 // no tip - time to create one
630
631
 // we're the non-Coroutine which starts the Coroutine system.
632
 // Add a single free block
633
 if (!setjmp(g_c->chunk_allocated)){
634
 ReserveStackSpace(g_c, NULL, COROUTINE_STARTUP_STACK_SIZE, NULL);
6 months ago
635
 }
6 months ago
636
 }
637
6 months ago
638
 Coroutine *cor = NULL;
6 months ago
639
 for (link = List_Begin(&g_c->free); Link_NextIsLink(link); link = Link_Next(link)){
6 months ago
640
 Coroutine *candidate = List_Link_Container(Coroutine, link, link);
641
 if (!candidate->guard) {
6 months ago
642
 // this must be the tip
6 months ago
643
 assert(candidate == g_c->tip);
6 months ago
644
645
 // If this is the only Coroutine in the system, go ahead and use it regardless of size.
646
 // Note: there can only be one free block if there's no other sort of blocks as we merge on free
647
 if (List_IsEmpty(&g_c->inactive) &&
648
 List_IsEmpty(&g_c->runable) &&
649
 List_IsEmpty(&g_c->waiting) ){
650
 if (g_c->stack_limit){
6 months ago
651
 size_t available = (unsigned char *)candidate - g_c->stack_limit - g_c->gap_after;
6 months ago
652
 size = available < size ? available : size;
653
 }
6 months ago
654
 Coroutine_FreeToIdleSize(candidate, start, size);
655
 return candidate;
7 months ago
656
 }
6 months ago
657
658
 // Not the only coroutine in the system - check size
659
 if (g_c->stack_limit){
660
 // there's a limit - see what that space allows....
6 months ago
661
 size_t available = (unsigned char *)candidate - g_c->stack_limit - g_c->gap_after;
6 months ago
662
663
 if (available < size){
664
 // not enough space for this coroutine
665
 return NULL;
666
 }
667
668
 if (available >= size + g_c->gap_before + g_c->gap_after + COROUTINE_MINIMUM_STACK_SIZE) {
669
 // not enough space for another coroutine - use all the space for this one
670
 size = available;
671
 }
7 months ago
672
 }
6 months ago
673
 Coroutine_FreeToIdleSize(candidate, start, size);
674
 return candidate;
9 months ago
4
675
 }
6 months ago
676
 if (candidate->size >= size && candidate > cor){
677
 // chunk big enough, and a better choice than cor
678
 cor = candidate;
679
 }
680
 }
681
682
 if (cor){
683
 // - work out whether we're splitting or using the whole chunk
684
 if (cor->size >= size + g_c->gap_before + g_c->gap_after + COROUTINE_MINIMUM_STACK_SIZE){
685
 // enough space for a second coroutine so split this free block
686
 cor->size = size;
687
 if (!setjmp(g_c->chunk_allocated)){
688
 longjmp(cor->buf, Chunk_Split);
6 months ago
689
 }
690
 }
6 months ago
691
 // cor now ready to use
692
 Coroutine_FreeToIdle(cor, start);
693
 return cor;
9 months ago
4
694
 }
695
6 months ago
696
 // No big-enough free blocks - check if there's space beyond the tip block
697
698
 if (g_c->stack_limit && g_c->stack_limit > (unsigned char *)g_c->tip->limit - sizeof(Coroutine) - size){
699
 // no space for a new stack block
700
 return NULL;
701
 }
702
 Coroutine *tip = g_c->tip;
703
 Coroutine *me = g_c->active;
704
 if (tip == me) {
705
 if (!setjmp(g_c->chunk_allocated)){
706
 ReserveStackSpace(g_c, me, StackTopNow() - me->limit, NULL);
707
 }
708
 } else {
709
 if (!setjmp(g_c->chunk_allocated)){
710
 longjmp(tip->buf, Chunk_Create);
711
 }
712
 }
713
6 months ago
714
 cor = List_Link_Container(Coroutine, link, List_GetTail(&g_c->free));
9 months ago
4
715
 assert(cor->state == Coroutine_Free);
6 months ago
716
 cor->size = size;
717
 cor->limit = (unsigned char *)cor - g_c->gap_after - size;
9 months ago
4
718
 cor->state = Coroutine_Idle;
719
 cor->start = start;
720
 cor->value = NULL;
6 months ago
721
 Link_Remove(&cor->link);
722
 List_AddHead(&g_c->inactive, &cor->link);
9 months ago
4
723
6 months ago
724
 g_c->report.coroutines_created += 1;
725
 return cor;
726
 }
9 months ago
727
6 months ago
728
729
 Coroutine *Coroutine_New(
730
 size_t stack,
731
 Coroutine_Start start
732
 ){
733
 assert(g_c);
734
 assert((g_c->state == Coroutines_Started && List_IsEmpty(&g_c->inactive)) || g_c->state == Coroutines_Active);
735
 assert(!Coroutine_StackHasOverrun());
736
737
 _Cor_Mutex_Lock(&g_c->mutex);
738
739
 Coroutine *cor = Coroutine_New_Lock_Assumed(stack, start);
740
741
 if (cor && cor->size > g_c->report.largest_stack){
742
 g_c->report.largest_stack = cor->size;
743
 }
744
745
 _Cor_Mutex_Unlock(&g_c->mutex);
746
9 months ago
4
747
 return cor;
748
 }
749
9 months ago
750
751
 void Coroutine_Delete(
752
 Coroutine *cor
753
 ){
6 months ago
754
 assert(!Coroutine_StackHasOverrun());
6 months ago
755
 if (cor){
756
 Coroutines *cors = cor->coroutines;
757
 _Cor_Mutex_Lock(&cors->mutex);
758
 assert(cor->state == Coroutine_Idle || cor->state == Coroutine_Complete);
759
 cor->state = Coroutine_Free;
6 months ago
760
 Link_Remove(&cor->link);
761
6 months ago
762
 // insert into free list
763
 List_AddHead(&cors->free, &cor->link);
6 months ago
764
765
 // Check for merge with following Coroutine
6 months ago
766
 List_Link *link = Link_Next(&cor->all_link);
6 months ago
767
 if (Link_NextIsLink(link)){
6 months ago
768
 Coroutine *listcor = List_Link_Container(Coroutine, all_link, link);
769
 if (listcor->state == Coroutine_Free){
6 months ago
770
 // merge
6 months ago
771
 cor->size += cor->limit - listcor->limit;
6 months ago
772
 cor->limit = listcor->limit;
773
 cor->guard = listcor->guard;
6 months ago
774
 Link_Remove(&listcor->all_link);
6 months ago
775
 Link_Remove(&listcor->link);
6 months ago
776
 if (g_c->tip == listcor){
777
 g_c->tip = cor;
778
 }
6 months ago
779
 }
780
 }
781
782
 // check for merge with prev coroutine
6 months ago
783
 link = Link_Prev(&cor->all_link);
6 months ago
784
 if (Link_PrevIsLink(link)){
6 months ago
785
 Coroutine *listcor = List_Link_Container(Coroutine, all_link, link);
786
 if (listcor->state == Coroutine_Free){
6 months ago
787
 // merge
6 months ago
788
 listcor->size += listcor->limit - cor->limit;
6 months ago
789
 listcor->limit = cor->limit;
790
 listcor->guard = cor->guard;
6 months ago
791
 Link_Remove(&cor->all_link);
6 months ago
792
 Link_Remove(&cor->link);
6 months ago
793
 if (g_c->tip == cor){
794
 g_c->tip = listcor;
795
 }
6 months ago
796
 }
797
 }
798
6 months ago
799
 _Cor_Mutex_Unlock(&cors->mutex);
800
 }
9 months ago
4
801
 }
802
9 months ago
803
8 months ago
804
 // Coroutine_Continue, assuming the mutex is claimed
805
 static void _Coroutine_Continue(
9 months ago
806
 Coroutine *cor,
807
 void *value,
808
 bool early
809
 ){
810
 Coroutines *cors = cor->coroutines;
9 months ago
4
811
 assert(cor->state == Coroutine_Idle || cor->state == Coroutine_Waiting);
812
 cor->entry_param = value;
813
 cor->state = Coroutine_Running;
6 months ago
814
 Link_Remove(&cor->link);
9 months ago
4
815
 if ( early ) {
9 months ago
816
 List_AddHead(&cors->runable, &cor->link);
9 months ago
4
817
 } else {
9 months ago
818
 List_AddTail(&cors->runable, &cor->link);
9 months ago
4
819
 }
8 months ago
820
 _Cor_Mutex_Unlock(&cors->waiting_mutex);
8 months ago
821
 }
822
823
824
 void Coroutine_Continue(
825
 Coroutine *cor,
826
 void *value,
827
 bool early
828
 ){
6 months ago
829
 assert(!Coroutine_StackHasOverrun());
8 months ago
830
 Coroutines *cors = cor->coroutines;
8 months ago
831
 _Cor_Mutex_Lock(&cors->mutex);
8 months ago
832
 _Coroutine_Continue(cor, value, early);
8 months ago
833
 _Cor_Mutex_Unlock(&cors->mutex);
9 months ago
4
834
 }
835
9 months ago
836
837
 void *Coroutine_Yield(
838
 void *value,
839
 Coroutine_YieldCallback on_yield,
9 months ago
840
 void *yield_me
9 months ago
841
 ){
6 months ago
842
 assert(g_c);
843
 Coroutine *me = g_c->active;
7 months ago
844
 assert(me);
6 months ago
845
 assert(!Coroutine_StackHasOverrun());
9 months ago
846
6 months ago
847
 _Cor_Mutex_Lock(&g_c->mutex);
9 months ago
848
 Coroutines *cors = me->coroutines;
6 months ago
849
 assert(me && me->state == Coroutine_Running && cors == g_c);
7 months ago
850
 me->stack_top = StackTopNow();
9 months ago
4
851
 me->value = value;
852
 me->state = Coroutine_Waiting;
9 months ago
853
6 months ago
854
 Link_Remove(&me->link);
8 months ago
855
 if (!List_IsEmpty(&cors->runable)){
8 months ago
856
 _Cor_Mutex_Unlock(&cors->waiting_mutex);
8 months ago
857
 }
9 months ago
858
 List_AddTail(&cors->waiting, &me->link);
9 months ago
859
9 months ago
860
 switch (setjmp(me->buf)){
861
 case Chunk_Initial:
8 months ago
862
 _Cor_Mutex_Unlock(&cors->mutex);
9 months ago
863
 on_yield(yield_me);
9 months ago
4
864
 Coroutine_RunNext();
7 months ago
865
 assert(false);
9 months ago
866
 case Chunk_Create:
6 months ago
867
 assert(me == g_c->tip);
868
 ReserveStackSpace(me->coroutines, me, me->stack_top - me->limit, NULL);
9 months ago
869
 assert(false);
870
 case Chunk_Enter:
871
 // arrive here with mutex locked
9 months ago
872
 cors->active = me;
6 months ago
873
 assert(!Coroutine_StackHasOverrun());
9 months ago
874
 // when we return here - we are running again
875
 assert(me->state == Coroutine_Running);
876
 void *res = me->entry_param;
8 months ago
877
 _Cor_Mutex_Unlock(&cors->mutex);
9 months ago
878
 return res;
9 months ago
4
879
 }
9 months ago
880
 return NULL;
9 months ago
4
881
 }
882
9 months ago
883
884
 void *Coroutine_GetValue(
885
 Coroutine *cor
886
 ){
9 months ago
4
887
 return cor->value;
888
 }
889
9 months ago
890
8 months ago
891
 Coroutine *Coroutine_GetActive(void)
9 months ago
4
892
 {
6 months ago
893
 return g_c ? g_c->active : NULL;
9 months ago
4
894
 }
895
9 months ago
896
8 months ago
897
 intptr_t Coroutine_GetStackHeadroom(void){
6 months ago
898
 assert(g_c);
899
 assert(!Coroutine_StackHasOverrun());
900
 Coroutine *me = g_c->active;
7 months ago
901
 if (!me){
902
 // no active coroutine
6 months ago
903
 unsigned char *stack_limit = g_c->stack_limit;
7 months ago
904
 if (stack_limit){
905
 // no stack limit - assume we'll use COROUTINE_STACK_SIZE
906
 return StackTopNow() - stack_limit;
907
 } else {
908
 // no information where the stack ends - return something
6 months ago
909
 return COROUTINE_MINIMUM_STACK_SIZE;
7 months ago
910
 }
911
 }
6 months ago
912
 return StackTopNow() - me->limit;
9 months ago
913
 }
914
915
7 months ago
916
 // This is used to avoid compiler warnings about returning the address of a local
917
 static inline void *StopAddressWarnings(void *p)
918
 {
919
 return p;
9 months ago
920
 }
921
922
7 months ago
923
 void *Coroutine_GetStackHWM(void){
6 months ago
924
 assert(g_c);
925
 assert(g_c->state == Coroutines_Active);
926
 assert(!Coroutine_StackHasOverrun());
7 months ago
927
 // Find where the guards end
928
 unsigned char *guard;
6 months ago
929
 for (guard = g_c->active->guard; Check_Guard(guard); guard += 4){
7 months ago
930
 // do nothing
931
 }
932
 return guard;
933
 }
8 months ago
934
935
7 months ago
936
 void Coroutine_ClearStackForHWM(void){
6 months ago
937
 assert(g_c);
938
 assert(g_c->state == Coroutines_Active);
939
 assert(!Coroutine_StackHasOverrun());
7 months ago
940
 unsigned char *end = StackTopNow() - GUARD_PATTERN_SIZE;
6 months ago
941
 for (unsigned char *guard = g_c->active->guard+GUARD_PATTERN_SIZE; guard <= end; guard += GUARD_PATTERN_SIZE){
7 months ago
942
 Apply_Guard(guard);
7 months ago
943
 }
944
 }
945
946
6 months ago
947
 static bool Coroutine_CanStartCoroutine_Lock_Assumed(
948
 size_t size
949
 ){
950
 assert(g_c);
951
 assert(g_c->state == Coroutines_Started || g_c->state == Coroutines_Active);
952
 assert(!Coroutine_StackHasOverrun());
953
954
 if (!g_c->stack_limit){
7 months ago
955
 return true;
956
 }
7 months ago
957
6 months ago
958
 if (!g_c->tip){
959
 return true;
960
 }
961
962
 if (g_c->tip->state == Coroutine_Free){
963
 // last block is free
964
 if ((unsigned char *)g_c->tip - g_c->stack_limit >= (ptrdiff_t)(g_c->gap_after + size)){
965
 // enough room in free block, which is the last block
966
 return true;
967
 }
968
 } else {
969
 // last block is allocated
970
 if (g_c->tip->limit - g_c->stack_limit >= (ptrdiff_t)(g_c->gap_before + g_c->gap_after + size)){
971
 // enough room after the last block, which is allocated
972
 return true;
973
 }
974
 }
975
976
 // not enough room between allocated blocks and stack limit, so check free list
977
 List_Link *link;
978
 for (link = List_Begin(&g_c->free); Link_NextIsLink(link); link = Link_Next(link)){
979
 Coroutine *cor = List_Link_Container(Coroutine, link, link);
980
 if (cor->size >= size){
981
 return true;
982
 }
983
 }
984
985
 return false;
7 months ago
986
 }
987
988
6 months ago
989
 bool Coroutine_CanStartCoroutine(
990
 size_t size
991
 ){
992
 _Cor_Mutex_Lock(&g_c->mutex);
993
994
 bool result = Coroutine_CanStartCoroutine_Lock_Assumed(size);
995
996
 _Cor_Mutex_Unlock(&g_c->mutex);
997
998
 return result;
999
 }
1000
8 months ago
1001
 void *Coroutine_GetCStackTop(void){
6 months ago
1002
 assert(!Coroutine_StackHasOverrun());
1003
 if ((g_c->state == Coroutines_Started || g_c->state == Coroutines_Active) && g_c->tip != g_c->active) {
1004
 return g_c->tip->stack_top;
7 months ago
1005
 } else {
1006
 return StackTopNow();
1007
 }
9 months ago
1008
 }
1009
1010
7 months ago
1011
 static unsigned char *StackTopNow(void){
7 months ago
1012
 unsigned char here[4];
1013
 return StopAddressWarnings(here);
1014
 }
1015
1016
9 months ago
1017
 struct Coroutine_ChainParam {
1018
 Coroutine_Start start;
1019
 void *value;
1020
 Coroutine *ret;
1021
 };
1022
1023
1024
 static void *Coroutine_ChainFn(
1025
 void *param
1026
 ){
1027
 struct Coroutine_ChainParam *params = (struct Coroutine_ChainParam *)param;
1028
 Coroutine_Continue(params->ret, params->start(params->value), true);
1029
 return NULL;
1030
 }
1031
1032
1033
 static void Coroutine_ChainYield(
1034
 void *unused
1035
 ){
1036
 (void)unused;
1037
 }
1038
1039
6 months ago
1040
 bool Coroutine_Chain(
6 months ago
1041
 size_t size,
9 months ago
1042
 Coroutine_Start start,
6 months ago
1043
 void *value,
1044
 void **result
9 months ago
1045
 ){
8 months ago
1046
 assert(Check_Guard(Coroutine_GetActive()->guard));
6 months ago
1047
 Coroutine *cor = Coroutine_New(size, Coroutine_ChainFn);
6 months ago
1048
 if (!cor){
1049
 // failed
1050
 return true;
1051
 }
9 months ago
1052
 struct Coroutine_ChainParam params = {
1053
 start,
1054
 value,
1055
 Coroutine_GetActive()
1056
 };
1057
 Coroutine_Continue(cor, &params, true);
1058
 void *res = Coroutine_Yield(NULL, Coroutine_ChainYield, NULL);
1059
 Coroutine_Delete(cor);
6 months ago
1060
 if (result){
1061
 *result = res;
1062
 }
1063
 // success!
1064
 return false;
9 months ago
1065
 }
1066
1067
9 months ago
1068
 bool Coroutine_IsRunning(
1069
 Coroutine *cor
1070
 )
9 months ago
4
1071
 {
9 months ago
1072
 int state = cor->state;
1073
 return state == Coroutine_Running || state == Coroutine_Waiting;
9 months ago
4
1074
 }
9 months ago
1075
1076
7 months ago
1077
 bool Coroutine_IsComplete(
1078
 Coroutine *cor
1079
 )
1080
 {
1081
 int state = cor->state;
1082
 return state == Coroutine_Complete;
1083
 }
1084
1085
8 months ago
1086
 bool Coroutine_IsStarted(void){
6 months ago
1087
 return g_c && (g_c->state == Coroutines_Active || g_c->state == Coroutines_Started);
9 months ago
1088
 }
6 months ago
1089
1090
 void _Coroutine_Dump(void){
1091
 char *state_to_text[] = {
1092
 "Free",
1093
 "Idle",
1094
 "Running",
1095
 "Waiting",
1096
 "Complete"
1097
 };
1098
 unsigned idx = 0;
1099
 List_Link *link;
1100
 for (link = List_Begin(&g_c->all); Link_NextIsLink(link); link = Link_Next(link)){
1101
 Coroutine *cor = List_Link_Container(Coroutine, all_link, link);
1102
 printf("%d) %p (%s) %ld%s\n", idx++, cor, state_to_text[cor->state], cor->size, cor == g_c->tip ? " (TIP)" : "");
1103
 }
1104
 }
1105