lstate.h (16101B)
1 /* 2 ** $Id: lstate.h $ 3 ** Global State 4 ** See Copyright Notice in lua.h 5 */ 6 7 #ifndef lstate_h 8 #define lstate_h 9 10 #include "lua.h" 11 12 13 /* Some header files included here need this definition */ 14 typedef struct CallInfo CallInfo; 15 16 17 #include "lobject.h" 18 #include "ltm.h" 19 #include "lzio.h" 20 21 22 /* 23 ** Some notes about garbage-collected objects: All objects in Lua must 24 ** be kept somehow accessible until being freed, so all objects always 25 ** belong to one (and only one) of these lists, using field 'next' of 26 ** the 'CommonHeader' for the link: 27 ** 28 ** 'allgc': all objects not marked for finalization; 29 ** 'finobj': all objects marked for finalization; 30 ** 'tobefnz': all objects ready to be finalized; 31 ** 'fixedgc': all objects that are not to be collected (currently 32 ** only small strings, such as reserved words). 33 ** 34 ** For the generational collector, some of these lists have marks for 35 ** generations. Each mark points to the first element in the list for 36 ** that particular generation; that generation goes until the next mark. 37 ** 38 ** 'allgc' -> 'survival': new objects; 39 ** 'survival' -> 'old': objects that survived one collection; 40 ** 'old1' -> 'reallyold': objects that became old in last collection; 41 ** 'reallyold' -> NULL: objects old for more than one cycle. 42 ** 43 ** 'finobj' -> 'finobjsur': new objects marked for finalization; 44 ** 'finobjsur' -> 'finobjold1': survived """"; 45 ** 'finobjold1' -> 'finobjrold': just old """"; 46 ** 'finobjrold' -> NULL: really old """". 47 ** 48 ** All lists can contain elements older than their main ages, due 49 ** to 'luaC_checkfinalizer' and 'udata2finalize', which move 50 ** objects between the normal lists and the "marked for finalization" 51 ** lists. Moreover, barriers can age young objects in young lists as 52 ** OLD0, which then become OLD1. However, a list never contains 53 ** elements younger than their main ages. 54 ** 55 ** The generational collector also uses a pointer 'firstold1', which 56 ** points to the first OLD1 object in the list. It is used to optimize 57 ** 'markold'. (Potentially OLD1 objects can be anywhere between 'allgc' 58 ** and 'reallyold', but often the list has no OLD1 objects or they are 59 ** after 'old1'.) Note the difference between it and 'old1': 60 ** 'firstold1': no OLD1 objects before this point; there can be all 61 ** ages after it. 62 ** 'old1': no objects younger than OLD1 after this point. 63 */ 64 65 /* 66 ** Moreover, there is another set of lists that control gray objects. 67 ** These lists are linked by fields 'gclist'. (All objects that 68 ** can become gray have such a field. The field is not the same 69 ** in all objects, but it always has this name.) Any gray object 70 ** must belong to one of these lists, and all objects in these lists 71 ** must be gray (with two exceptions explained below): 72 ** 73 ** 'gray': regular gray objects, still waiting to be visited. 74 ** 'grayagain': objects that must be revisited at the atomic phase. 75 ** That includes 76 ** - black objects got in a write barrier; 77 ** - all kinds of weak tables during propagation phase; 78 ** - all threads. 79 ** 'weak': tables with weak values to be cleared; 80 ** 'ephemeron': ephemeron tables with white->white entries; 81 ** 'allweak': tables with weak keys and/or weak values to be cleared. 82 ** 83 ** The exceptions to that "gray rule" are: 84 ** - TOUCHED2 objects in generational mode stay in a gray list (because 85 ** they must be visited again at the end of the cycle), but they are 86 ** marked black because assignments to them must activate barriers (to 87 ** move them back to TOUCHED1). 88 ** - Open upvales are kept gray to avoid barriers, but they stay out 89 ** of gray lists. (They don't even have a 'gclist' field.) 90 */ 91 92 93 94 /* 95 ** About 'nCcalls': This count has two parts: the lower 16 bits counts 96 ** the number of recursive invocations in the C stack; the higher 97 ** 16 bits counts the number of non-yieldable calls in the stack. 98 ** (They are together so that we can change and save both with one 99 ** instruction.) 100 */ 101 102 103 /* true if this thread does not have non-yieldable calls in the stack */ 104 #define yieldable(L) (((L)->nCcalls & 0xffff0000) == 0) 105 106 /* real number of C calls */ 107 #define getCcalls(L) ((L)->nCcalls & 0xffff) 108 109 110 /* Increment the number of non-yieldable calls */ 111 #define incnny(L) ((L)->nCcalls += 0x10000) 112 113 /* Decrement the number of non-yieldable calls */ 114 #define decnny(L) ((L)->nCcalls -= 0x10000) 115 116 /* Non-yieldable call increment */ 117 #define nyci (0x10000 | 1) 118 119 120 121 122 struct lua_longjmp; /* defined in ldo.c */ 123 124 125 /* 126 ** Atomic type (relative to signals) to better ensure that 'lua_sethook' 127 ** is thread safe 128 */ 129 #if !defined(l_signalT) 130 #include <signal.h> 131 #define l_signalT sig_atomic_t 132 #endif 133 134 135 /* 136 ** Extra stack space to handle TM calls and some other extras. This 137 ** space is not included in 'stack_last'. It is used only to avoid stack 138 ** checks, either because the element will be promptly popped or because 139 ** there will be a stack check soon after the push. Function frames 140 ** never use this extra space, so it does not need to be kept clean. 141 */ 142 #define EXTRA_STACK 5 143 144 145 /* 146 ** Size of cache for strings in the API. 'N' is the number of 147 ** sets (better be a prime) and "M" is the size of each set. 148 ** (M == 1 makes a direct cache.) 149 */ 150 #if !defined(STRCACHE_N) 151 #define STRCACHE_N 53 152 #define STRCACHE_M 2 153 #endif 154 155 156 #define BASIC_STACK_SIZE (2*LUA_MINSTACK) 157 158 #define stacksize(th) cast_int((th)->stack_last.p - (th)->stack.p) 159 160 161 /* kinds of Garbage Collection */ 162 #define KGC_INC 0 /* incremental gc */ 163 #define KGC_GENMINOR 1 /* generational gc in minor (regular) mode */ 164 #define KGC_GENMAJOR 2 /* generational in major mode */ 165 166 167 typedef struct stringtable { 168 TString **hash; /* array of buckets (linked lists of strings) */ 169 int nuse; /* number of elements */ 170 int size; /* number of buckets */ 171 } stringtable; 172 173 174 /* 175 ** Information about a call. 176 ** About union 'u': 177 ** - field 'l' is used only for Lua functions; 178 ** - field 'c' is used only for C functions. 179 ** About union 'u2': 180 ** - field 'funcidx' is used only by C functions while doing a 181 ** protected call; 182 ** - field 'nyield' is used only while a function is "doing" an 183 ** yield (from the yield until the next resume); 184 ** - field 'nres' is used only while closing tbc variables when 185 ** returning from a function; 186 */ 187 struct CallInfo { 188 StkIdRel func; /* function index in the stack */ 189 StkIdRel top; /* top for this function */ 190 struct CallInfo *previous, *next; /* dynamic call link */ 191 union { 192 struct { /* only for Lua functions */ 193 const Instruction *savedpc; 194 volatile l_signalT trap; /* function is tracing lines/counts */ 195 int nextraargs; /* # of extra arguments in vararg functions */ 196 } l; 197 struct { /* only for C functions */ 198 lua_KFunction k; /* continuation in case of yields */ 199 ptrdiff_t old_errfunc; 200 lua_KContext ctx; /* context info. in case of yields */ 201 } c; 202 } u; 203 union { 204 int funcidx; /* called-function index */ 205 int nyield; /* number of values yielded */ 206 int nres; /* number of values returned */ 207 } u2; 208 l_uint32 callstatus; 209 }; 210 211 212 /* 213 ** Maximum expected number of results from a function 214 ** (must fit in CIST_NRESULTS). 215 */ 216 #define MAXRESULTS 250 217 218 219 /* 220 ** Bits in CallInfo status 221 */ 222 /* bits 0-7 are the expected number of results from this function + 1 */ 223 #define CIST_NRESULTS 0xffu 224 225 /* bits 8-11 count call metamethods (and their extra arguments) */ 226 #define CIST_CCMT 8 /* the offset, not the mask */ 227 #define MAX_CCMT (0xfu << CIST_CCMT) 228 229 /* Bits 12-14 are used for CIST_RECST (see below) */ 230 #define CIST_RECST 12 /* the offset, not the mask */ 231 232 /* call is running a C function (still in first 16 bits) */ 233 #define CIST_C (1u << (CIST_RECST + 3)) 234 /* call is on a fresh "luaV_execute" frame */ 235 #define CIST_FRESH cast(l_uint32, CIST_C << 1) 236 /* function is closing tbc variables */ 237 #define CIST_CLSRET (CIST_FRESH << 1) 238 /* function has tbc variables to close */ 239 #define CIST_TBC (CIST_CLSRET << 1) 240 /* original value of 'allowhook' */ 241 #define CIST_OAH (CIST_TBC << 1) 242 /* call is running a debug hook */ 243 #define CIST_HOOKED (CIST_OAH << 1) 244 /* doing a yieldable protected call */ 245 #define CIST_YPCALL (CIST_HOOKED << 1) 246 /* call was tail called */ 247 #define CIST_TAIL (CIST_YPCALL << 1) 248 /* last hook called yielded */ 249 #define CIST_HOOKYIELD (CIST_TAIL << 1) 250 /* function "called" a finalizer */ 251 #define CIST_FIN (CIST_HOOKYIELD << 1) 252 #if defined(LUA_COMPAT_LT_LE) 253 /* using __lt for __le */ 254 #define CIST_LEQ (CIST_FIN << 1) 255 #endif 256 257 258 #define get_nresults(cs) (cast_int((cs) & CIST_NRESULTS) - 1) 259 260 /* 261 ** Field CIST_RECST stores the "recover status", used to keep the error 262 ** status while closing to-be-closed variables in coroutines, so that 263 ** Lua can correctly resume after an yield from a __close method called 264 ** because of an error. (Three bits are enough for error status.) 265 */ 266 #define getcistrecst(ci) (((ci)->callstatus >> CIST_RECST) & 7) 267 #define setcistrecst(ci,st) \ 268 check_exp(((st) & 7) == (st), /* status must fit in three bits */ \ 269 ((ci)->callstatus = ((ci)->callstatus & ~(7u << CIST_RECST)) \ 270 | (cast(l_uint32, st) << CIST_RECST))) 271 272 273 /* active function is a Lua function */ 274 #define isLua(ci) (!((ci)->callstatus & CIST_C)) 275 276 /* call is running Lua code (not a hook) */ 277 #define isLuacode(ci) (!((ci)->callstatus & (CIST_C | CIST_HOOKED))) 278 279 280 #define setoah(ci,v) \ 281 ((ci)->callstatus = ((v) ? (ci)->callstatus | CIST_OAH \ 282 : (ci)->callstatus & ~CIST_OAH)) 283 #define getoah(ci) (((ci)->callstatus & CIST_OAH) ? 1 : 0) 284 285 286 /* 287 ** 'per thread' state 288 */ 289 struct lua_State { 290 CommonHeader; 291 lu_byte allowhook; 292 TStatus status; 293 StkIdRel top; /* first free slot in the stack */ 294 struct global_State *l_G; 295 CallInfo *ci; /* call info for current function */ 296 StkIdRel stack_last; /* end of stack (last element + 1) */ 297 StkIdRel stack; /* stack base */ 298 UpVal *openupval; /* list of open upvalues in this stack */ 299 StkIdRel tbclist; /* list of to-be-closed variables */ 300 GCObject *gclist; 301 struct lua_State *twups; /* list of threads with open upvalues */ 302 struct lua_longjmp *errorJmp; /* current error recover point */ 303 CallInfo base_ci; /* CallInfo for first level (C host) */ 304 volatile lua_Hook hook; 305 ptrdiff_t errfunc; /* current error handling function (stack index) */ 306 l_uint32 nCcalls; /* number of nested non-yieldable or C calls */ 307 int oldpc; /* last pc traced */ 308 int nci; /* number of items in 'ci' list */ 309 int basehookcount; 310 int hookcount; 311 volatile l_signalT hookmask; 312 struct { /* info about transferred values (for call/return hooks) */ 313 int ftransfer; /* offset of first value transferred */ 314 int ntransfer; /* number of values transferred */ 315 } transferinfo; 316 }; 317 318 319 /* 320 ** thread state + extra space 321 */ 322 typedef struct LX { 323 lu_byte extra_[LUA_EXTRASPACE]; 324 lua_State l; 325 } LX; 326 327 328 /* 329 ** 'global state', shared by all threads of this state 330 */ 331 typedef struct global_State { 332 lua_Alloc frealloc; /* function to reallocate memory */ 333 void *ud; /* auxiliary data to 'frealloc' */ 334 l_mem GCtotalbytes; /* number of bytes currently allocated + debt */ 335 l_mem GCdebt; /* bytes counted but not yet allocated */ 336 l_mem GCmarked; /* number of objects marked in a GC cycle */ 337 l_mem GCmajorminor; /* auxiliary counter to control major-minor shifts */ 338 stringtable strt; /* hash table for strings */ 339 TValue l_registry; 340 TValue nilvalue; /* a nil value */ 341 unsigned int seed; /* randomized seed for hashes */ 342 lu_byte gcparams[LUA_GCPN]; 343 lu_byte currentwhite; 344 lu_byte gcstate; /* state of garbage collector */ 345 lu_byte gckind; /* kind of GC running */ 346 lu_byte gcstopem; /* stops emergency collections */ 347 lu_byte gcstp; /* control whether GC is running */ 348 lu_byte gcemergency; /* true if this is an emergency collection */ 349 GCObject *allgc; /* list of all collectable objects */ 350 GCObject **sweepgc; /* current position of sweep in list */ 351 GCObject *finobj; /* list of collectable objects with finalizers */ 352 GCObject *gray; /* list of gray objects */ 353 GCObject *grayagain; /* list of objects to be traversed atomically */ 354 GCObject *weak; /* list of tables with weak values */ 355 GCObject *ephemeron; /* list of ephemeron tables (weak keys) */ 356 GCObject *allweak; /* list of all-weak tables */ 357 GCObject *tobefnz; /* list of userdata to be GC */ 358 GCObject *fixedgc; /* list of objects not to be collected */ 359 /* fields for generational collector */ 360 GCObject *survival; /* start of objects that survived one GC cycle */ 361 GCObject *old1; /* start of old1 objects */ 362 GCObject *reallyold; /* objects more than one cycle old ("really old") */ 363 GCObject *firstold1; /* first OLD1 object in the list (if any) */ 364 GCObject *finobjsur; /* list of survival objects with finalizers */ 365 GCObject *finobjold1; /* list of old1 objects with finalizers */ 366 GCObject *finobjrold; /* list of really old objects with finalizers */ 367 struct lua_State *twups; /* list of threads with open upvalues */ 368 lua_CFunction panic; /* to be called in unprotected errors */ 369 TString *memerrmsg; /* message for memory-allocation errors */ 370 TString *tmname[TM_N]; /* array with tag-method names */ 371 struct Table *mt[LUA_NUMTYPES]; /* metatables for basic types */ 372 TString *strcache[STRCACHE_N][STRCACHE_M]; /* cache for strings in API */ 373 lua_WarnFunction warnf; /* warning function */ 374 void *ud_warn; /* auxiliary data to 'warnf' */ 375 LX mainth; /* main thread of this state */ 376 } global_State; 377 378 379 #define G(L) (L->l_G) 380 #define mainthread(G) (&(G)->mainth.l) 381 382 /* 383 ** 'g->nilvalue' being a nil value flags that the state was completely 384 ** build. 385 */ 386 #define completestate(g) ttisnil(&g->nilvalue) 387 388 389 /* 390 ** Union of all collectable objects (only for conversions) 391 ** ISO C99, 6.5.2.3 p.5: 392 ** "if a union contains several structures that share a common initial 393 ** sequence [...], and if the union object currently contains one 394 ** of these structures, it is permitted to inspect the common initial 395 ** part of any of them anywhere that a declaration of the complete type 396 ** of the union is visible." 397 */ 398 union GCUnion { 399 GCObject gc; /* common header */ 400 struct TString ts; 401 struct Udata u; 402 union Closure cl; 403 struct Table h; 404 struct Proto p; 405 struct lua_State th; /* thread */ 406 struct UpVal upv; 407 }; 408 409 410 /* 411 ** ISO C99, 6.7.2.1 p.14: 412 ** "A pointer to a union object, suitably converted, points to each of 413 ** its members [...], and vice versa." 414 */ 415 #define cast_u(o) cast(union GCUnion *, (o)) 416 417 /* macros to convert a GCObject into a specific value */ 418 #define gco2ts(o) \ 419 check_exp(novariant((o)->tt) == LUA_TSTRING, &((cast_u(o))->ts)) 420 #define gco2u(o) check_exp((o)->tt == LUA_VUSERDATA, &((cast_u(o))->u)) 421 #define gco2lcl(o) check_exp((o)->tt == LUA_VLCL, &((cast_u(o))->cl.l)) 422 #define gco2ccl(o) check_exp((o)->tt == LUA_VCCL, &((cast_u(o))->cl.c)) 423 #define gco2cl(o) \ 424 check_exp(novariant((o)->tt) == LUA_TFUNCTION, &((cast_u(o))->cl)) 425 #define gco2t(o) check_exp((o)->tt == LUA_VTABLE, &((cast_u(o))->h)) 426 #define gco2p(o) check_exp((o)->tt == LUA_VPROTO, &((cast_u(o))->p)) 427 #define gco2th(o) check_exp((o)->tt == LUA_VTHREAD, &((cast_u(o))->th)) 428 #define gco2upv(o) check_exp((o)->tt == LUA_VUPVAL, &((cast_u(o))->upv)) 429 430 431 /* 432 ** macro to convert a Lua object into a GCObject 433 ** (The access to 'tt' tries to ensure that 'v' is actually a Lua object.) 434 */ 435 #define obj2gco(v) check_exp((v)->tt >= LUA_TSTRING, &(cast_u(v)->gc)) 436 437 438 /* actual number of total memory allocated */ 439 #define gettotalbytes(g) ((g)->GCtotalbytes - (g)->GCdebt) 440 441 442 LUAI_FUNC void luaE_setdebt (global_State *g, l_mem debt); 443 LUAI_FUNC void luaE_freethread (lua_State *L, lua_State *L1); 444 LUAI_FUNC lu_mem luaE_threadsize (lua_State *L); 445 LUAI_FUNC CallInfo *luaE_extendCI (lua_State *L); 446 LUAI_FUNC void luaE_shrinkCI (lua_State *L); 447 LUAI_FUNC void luaE_checkcstack (lua_State *L); 448 LUAI_FUNC void luaE_incCstack (lua_State *L); 449 LUAI_FUNC void luaE_warning (lua_State *L, const char *msg, int tocont); 450 LUAI_FUNC void luaE_warnerror (lua_State *L, const char *where); 451 LUAI_FUNC TStatus luaE_resetthread (lua_State *L, TStatus status); 452 453 454 #endif 455