** For each non-marked thread, simulates a barrier between each open ** upvalue and its value. (If the thread is collected, the value will be ** assigned to the upvalue, but then it can be too late for the barrier ** to act. The "barrier" does not need to check colors: A non-marked ** thread must be young; upvalues cannot be older than their threads; so ** any visited upvalue must be young too.) A
| 365 | ** upvalue later, it will be linked in the list again.) |
| 366 | */ |
| 367 | static int remarkupvals (global_State *g) { |
| 368 | lua_State *thread; |
| 369 | lua_State **p = &g->twups; |
| 370 | int work = 0; /* estimate of how much work was done here */ |
| 371 | while ((thread = *p) != NULL) { |
| 372 | work++; |
| 373 | if (!iswhite(thread) && thread->openupval != NULL) |
| 374 | p = &thread->twups; /* keep marked thread with upvalues in the list */ |
| 375 | else { /* thread is not marked or without upvalues */ |
| 376 | UpVal *uv; |
| 377 | lua_assert(!isold(thread) || thread->openupval == NULL); |
| 378 | *p = thread->twups; /* remove thread from the list */ |
| 379 | thread->twups = thread; /* mark that it is out of list */ |
| 380 | for (uv = thread->openupval; uv != NULL; uv = uv->u.open.next) { |
| 381 | lua_assert(getage(uv) <= getage(thread)); |
| 382 | work++; |
| 383 | if (!iswhite(uv)) { /* upvalue already visited? */ |
| 384 | lua_assert(upisopen(uv) && isgray(uv)); |
| 385 | markvalue(g, uv->v.p); /* mark its value */ |
| 386 | } |
| 387 | } |
| 388 | } |
| 389 | } |
| 390 | return work; |
| 391 | } |
| 392 | |
| 393 | |
| 394 | static void cleargraylists (global_State *g) { |