1 /* $NetBSD: lstate.h,v 1.11 2023/06/08 21:12:08 nikita Exp $ */ 2 3 /* 4 ** Id: lstate.h 5 ** Global State 6 ** See Copyright Notice in lua.h 7 */ 8 9 #ifndef lstate_h 10 #define lstate_h 11 12 #include "lua.h" 13 14 15 /* Some header files included here need this definition */ 16 typedef struct CallInfo CallInfo; 17 18 19 #include "lobject.h" 20 #include "ltm.h" 21 #include "lzio.h" 22 23 24 /* 25 ** Some notes about garbage-collected objects: All objects in Lua must 26 ** be kept somehow accessible until being freed, so all objects always 27 ** belong to one (and only one) of these lists, using field 'next' of 28 ** the 'CommonHeader' for the link: 29 ** 30 ** 'allgc': all objects not marked for finalization; 31 ** 'finobj': all objects marked for finalization; 32 ** 'tobefnz': all objects ready to be finalized; 33 ** 'fixedgc': all objects that are not to be collected (currently 34 ** only small strings, such as reserved words). 35 ** 36 ** For the generational collector, some of these lists have marks for 37 ** generations. Each mark points to the first element in the list for 38 ** that particular generation; that generation goes until the next mark. 39 ** 40 ** 'allgc' -> 'survival': new objects; 41 ** 'survival' -> 'old': objects that survived one collection; 42 ** 'old1' -> 'reallyold': objects that became old in last collection; 43 ** 'reallyold' -> NULL: objects old for more than one cycle. 44 ** 45 ** 'finobj' -> 'finobjsur': new objects marked for finalization; 46 ** 'finobjsur' -> 'finobjold1': survived """"; 47 ** 'finobjold1' -> 'finobjrold': just old """"; 48 ** 'finobjrold' -> NULL: really old """". 49 ** 50 ** All lists can contain elements older than their main ages, due 51 ** to 'luaC_checkfinalizer' and 'udata2finalize', which move 52 ** objects between the normal lists and the "marked for finalization" 53 ** lists. Moreover, barriers can age young objects in young lists as 54 ** OLD0, which then become OLD1. However, a list never contains 55 ** elements younger than their main ages. 56 ** 57 ** The generational collector also uses a pointer 'firstold1', which 58 ** points to the first OLD1 object in the list. It is used to optimize 59 ** 'markold'. (Potentially OLD1 objects can be anywhere between 'allgc' 60 ** and 'reallyold', but often the list has no OLD1 objects or they are 61 ** after 'old1'.) Note the difference between it and 'old1': 62 ** 'firstold1': no OLD1 objects before this point; there can be all 63 ** ages after it. 64 ** 'old1': no objects younger than OLD1 after this point. 65 */ 66 67 /* 68 ** Moreover, there is another set of lists that control gray objects. 69 ** These lists are linked by fields 'gclist'. (All objects that 70 ** can become gray have such a field. The field is not the same 71 ** in all objects, but it always has this name.) Any gray object 72 ** must belong to one of these lists, and all objects in these lists 73 ** must be gray (with two exceptions explained below): 74 ** 75 ** 'gray': regular gray objects, still waiting to be visited. 76 ** 'grayagain': objects that must be revisited at the atomic phase. 77 ** That includes 78 ** - black objects got in a write barrier; 79 ** - all kinds of weak tables during propagation phase; 80 ** - all threads. 81 ** 'weak': tables with weak values to be cleared; 82 ** 'ephemeron': ephemeron tables with white->white entries; 83 ** 'allweak': tables with weak keys and/or weak values to be cleared. 84 ** 85 ** The exceptions to that "gray rule" are: 86 ** - TOUCHED2 objects in generational mode stay in a gray list (because 87 ** they must be visited again at the end of the cycle), but they are 88 ** marked black because assignments to them must activate barriers (to 89 ** move them back to TOUCHED1). 90 ** - Open upvales are kept gray to avoid barriers, but they stay out 91 ** of gray lists. (They don't even have a 'gclist' field.) 92 */ 93 94 95 96 /* 97 ** About 'nCcalls': This count has two parts: the lower 16 bits counts 98 ** the number of recursive invocations in the C stack; the higher 99 ** 16 bits counts the number of non-yieldable calls in the stack. 100 ** (They are together so that we can change and save both with one 101 ** instruction.) 102 */ 103 104 105 /* true if this thread does not have non-yieldable calls in the stack */ 106 #define yieldable(L) (((L)->nCcalls & 0xffff0000) == 0) 107 108 /* real number of C calls */ 109 #define getCcalls(L) ((L)->nCcalls & 0xffff) 110 111 112 /* Increment the number of non-yieldable calls */ 113 #define incnny(L) ((L)->nCcalls += 0x10000) 114 115 /* Decrement the number of non-yieldable calls */ 116 #define decnny(L) ((L)->nCcalls -= 0x10000) 117 118 /* Non-yieldable call increment */ 119 #define nyci (0x10000 | 1) 120 121 122 123 124 struct lua_longjmp; /* defined in ldo.c */ 125 126 127 /* 128 ** Atomic type (relative to signals) to better ensure that 'lua_sethook' 129 ** is thread safe 130 */ 131 #if !defined(l_signalT) 132 #include <signal.h> 133 #define l_signalT sig_atomic_t 134 #endif 135 136 137 /* 138 ** Extra stack space to handle TM calls and some other extras. This 139 ** space is not included in 'stack_last'. It is used only to avoid stack 140 ** checks, either because the element will be promptly popped or because 141 ** there will be a stack check soon after the push. Function frames 142 ** never use this extra space, so it does not need to be kept clean. 143 */ 144 #define EXTRA_STACK 5 145 146 147 #define BASIC_STACK_SIZE (2*LUA_MINSTACK) 148 149 #define stacksize(th) cast_int((th)->stack_last.p - (th)->stack.p) 150 151 152 /* kinds of Garbage Collection */ 153 #define KGC_INC 0 /* incremental gc */ 154 #define KGC_GEN 1 /* generational gc */ 155 156 157 typedef struct stringtable { 158 TString **hash; 159 int nuse; /* number of elements */ 160 int size; 161 } stringtable; 162 163 164 /* 165 ** Information about a call. 166 ** About union 'u': 167 ** - field 'l' is used only for Lua functions; 168 ** - field 'c' is used only for C functions. 169 ** About union 'u2': 170 ** - field 'funcidx' is used only by C functions while doing a 171 ** protected call; 172 ** - field 'nyield' is used only while a function is "doing" an 173 ** yield (from the yield until the next resume); 174 ** - field 'nres' is used only while closing tbc variables when 175 ** returning from a function; 176 ** - field 'transferinfo' is used only during call/returnhooks, 177 ** before the function starts or after it ends. 178 */ 179 struct CallInfo { 180 StkIdRel func; /* function index in the stack */ 181 StkIdRel top; /* top for this function */ 182 struct CallInfo *previous, *next; /* dynamic call link */ 183 union { 184 struct { /* only for Lua functions */ 185 const Instruction *savedpc; 186 volatile l_signalT trap; 187 int nextraargs; /* # of extra arguments in vararg functions */ 188 } l; 189 struct { /* only for C functions */ 190 lua_KFunction k; /* continuation in case of yields */ 191 ptrdiff_t old_errfunc; 192 lua_KContext ctx; /* context info. in case of yields */ 193 } c; 194 } u; 195 union { 196 int funcidx; /* called-function index */ 197 int nyield; /* number of values yielded */ 198 int nres; /* number of values returned */ 199 struct { /* info about transferred values (for call/return hooks) */ 200 unsigned short ftransfer; /* offset of first value transferred */ 201 unsigned short ntransfer; /* number of values transferred */ 202 } transferinfo; 203 } u2; 204 short nresults; /* expected number of results from this function */ 205 unsigned short callstatus; 206 }; 207 208 209 /* 210 ** Bits in CallInfo status 211 */ 212 #define CIST_OAH (1<<0) /* original value of 'allowhook' */ 213 #define CIST_C (1<<1) /* call is running a C function */ 214 #define CIST_FRESH (1<<2) /* call is on a fresh "luaV_execute" frame */ 215 #define CIST_HOOKED (1<<3) /* call is running a debug hook */ 216 #define CIST_YPCALL (1<<4) /* doing a yieldable protected call */ 217 #define CIST_TAIL (1<<5) /* call was tail called */ 218 #define CIST_HOOKYIELD (1<<6) /* last hook called yielded */ 219 #define CIST_FIN (1<<7) /* function "called" a finalizer */ 220 #define CIST_TRAN (1<<8) /* 'ci' has transfer information */ 221 #define CIST_CLSRET (1<<9) /* function is closing tbc variables */ 222 /* Bits 10-12 are used for CIST_RECST (see below) */ 223 #define CIST_RECST 10 224 #if defined(LUA_COMPAT_LT_LE) 225 #define CIST_LEQ (1<<13) /* using __lt for __le */ 226 #endif 227 228 229 /* 230 ** Field CIST_RECST stores the "recover status", used to keep the error 231 ** status while closing to-be-closed variables in coroutines, so that 232 ** Lua can correctly resume after an yield from a __close method called 233 ** because of an error. (Three bits are enough for error status.) 234 */ 235 #define getcistrecst(ci) (((ci)->callstatus >> CIST_RECST) & 7) 236 #define setcistrecst(ci,st) \ 237 check_exp(((st) & 7) == (st), /* status must fit in three bits */ \ 238 ((ci)->callstatus = ((ci)->callstatus & ~(7 << CIST_RECST)) \ 239 | ((st) << CIST_RECST))) 240 241 242 /* active function is a Lua function */ 243 #define isLua(ci) (!((ci)->callstatus & CIST_C)) 244 245 /* call is running Lua code (not a hook) */ 246 #define isLuacode(ci) (!((ci)->callstatus & (CIST_C | CIST_HOOKED))) 247 248 /* assume that CIST_OAH has offset 0 and that 'v' is strictly 0/1 */ 249 #define setoah(st,v) ((st) = ((st) & ~CIST_OAH) | (v)) 250 #define getoah(st) ((st) & CIST_OAH) 251 252 253 /* 254 ** 'global state', shared by all threads of this state 255 */ 256 typedef struct global_State { 257 lua_Alloc frealloc; /* function to reallocate memory */ 258 void *ud; /* auxiliary data to 'frealloc' */ 259 l_mem totalbytes; /* number of bytes currently allocated - GCdebt */ 260 l_mem GCdebt; /* bytes allocated not yet compensated by the collector */ 261 lu_mem GCestimate; /* an estimate of the non-garbage memory in use */ 262 lu_mem lastatomic; /* see function 'genstep' in file 'lgc.c' */ 263 stringtable strt; /* hash table for strings */ 264 TValue l_registry; 265 TValue nilvalue; /* a nil value */ 266 unsigned int seed; /* randomized seed for hashes */ 267 lu_byte currentwhite; 268 lu_byte gcstate; /* state of garbage collector */ 269 lu_byte gckind; /* kind of GC running */ 270 lu_byte gcstopem; /* stops emergency collections */ 271 lu_byte genminormul; /* control for minor generational collections */ 272 lu_byte genmajormul; /* control for major generational collections */ 273 lu_byte gcstp; /* control whether GC is running */ 274 lu_byte gcemergency; /* true if this is an emergency collection */ 275 lu_byte gcpause; /* size of pause between successive GCs */ 276 lu_byte gcstepmul; /* GC "speed" */ 277 lu_byte gcstepsize; /* (log2 of) GC granularity */ 278 GCObject *allgc; /* list of all collectable objects */ 279 GCObject **sweepgc; /* current position of sweep in list */ 280 GCObject *finobj; /* list of collectable objects with finalizers */ 281 GCObject *gray; /* list of gray objects */ 282 GCObject *grayagain; /* list of objects to be traversed atomically */ 283 GCObject *weak; /* list of tables with weak values */ 284 GCObject *ephemeron; /* list of ephemeron tables (weak keys) */ 285 GCObject *allweak; /* list of all-weak tables */ 286 GCObject *tobefnz; /* list of userdata to be GC */ 287 GCObject *fixedgc; /* list of objects not to be collected */ 288 /* fields for generational collector */ 289 GCObject *survival; /* start of objects that survived one GC cycle */ 290 GCObject *old1; /* start of old1 objects */ 291 GCObject *reallyold; /* objects more than one cycle old ("really old") */ 292 GCObject *firstold1; /* first OLD1 object in the list (if any) */ 293 GCObject *finobjsur; /* list of survival objects with finalizers */ 294 GCObject *finobjold1; /* list of old1 objects with finalizers */ 295 GCObject *finobjrold; /* list of really old objects with finalizers */ 296 struct lua_State *twups; /* list of threads with open upvalues */ 297 lua_CFunction panic; /* to be called in unprotected errors */ 298 struct lua_State *mainthread; 299 TString *memerrmsg; /* message for memory-allocation errors */ 300 TString *tmname[TM_N]; /* array with tag-method names */ 301 struct Table *mt[LUA_NUMTYPES]; /* metatables for basic types */ 302 TString *strcache[STRCACHE_N][STRCACHE_M]; /* cache for strings in API */ 303 lua_WarnFunction warnf; /* warning function */ 304 void *ud_warn; /* auxiliary data to 'warnf' */ 305 } global_State; 306 307 308 /* 309 ** 'per thread' state 310 */ 311 struct lua_State { 312 CommonHeader; 313 lu_byte status; 314 lu_byte allowhook; 315 unsigned short nci; /* number of items in 'ci' list */ 316 StkIdRel top; /* first free slot in the stack */ 317 global_State *l_G; 318 CallInfo *ci; /* call info for current function */ 319 StkIdRel stack_last; /* end of stack (last element + 1) */ 320 StkIdRel stack; /* stack base */ 321 UpVal *openupval; /* list of open upvalues in this stack */ 322 StkIdRel tbclist; /* list of to-be-closed variables */ 323 GCObject *gclist; 324 struct lua_State *twups; /* list of threads with open upvalues */ 325 struct lua_longjmp *errorJmp; /* current error recover point */ 326 CallInfo base_ci; /* CallInfo for first level (C calling Lua) */ 327 volatile lua_Hook hook; 328 ptrdiff_t errfunc; /* current error handling function (stack index) */ 329 l_uint32 nCcalls; /* number of nested (non-yieldable | C) calls */ 330 int oldpc; /* last pc traced */ 331 int basehookcount; 332 int hookcount; 333 volatile l_signalT hookmask; 334 }; 335 336 337 #define G(L) (L->l_G) 338 339 /* 340 ** 'g->nilvalue' being a nil value flags that the state was completely 341 ** build. 342 */ 343 #define completestate(g) ttisnil(&g->nilvalue) 344 345 346 /* 347 ** Union of all collectable objects (only for conversions) 348 ** ISO C99, 6.5.2.3 p.5: 349 ** "if a union contains several structures that share a common initial 350 ** sequence [...], and if the union object currently contains one 351 ** of these structures, it is permitted to inspect the common initial 352 ** part of any of them anywhere that a declaration of the complete type 353 ** of the union is visible." 354 */ 355 union GCUnion { 356 GCObject gc; /* common header */ 357 struct TString ts; 358 struct Udata u; 359 union Closure cl; 360 struct Table h; 361 struct Proto p; 362 struct lua_State th; /* thread */ 363 struct UpVal upv; 364 }; 365 366 367 /* 368 ** ISO C99, 6.7.2.1 p.14: 369 ** "A pointer to a union object, suitably converted, points to each of 370 ** its members [...], and vice versa." 371 */ 372 #define cast_u(o) cast(union GCUnion *, (o)) 373 374 /* macros to convert a GCObject into a specific value */ 375 #define gco2ts(o) \ 376 check_exp(novariant((o)->tt) == LUA_TSTRING, &((cast_u(o))->ts)) 377 #define gco2u(o) check_exp((o)->tt == LUA_VUSERDATA, &((cast_u(o))->u)) 378 #define gco2lcl(o) check_exp((o)->tt == LUA_VLCL, &((cast_u(o))->cl.l)) 379 #define gco2ccl(o) check_exp((o)->tt == LUA_VCCL, &((cast_u(o))->cl.c)) 380 #define gco2cl(o) \ 381 check_exp(novariant((o)->tt) == LUA_TFUNCTION, &((cast_u(o))->cl)) 382 #define gco2t(o) check_exp((o)->tt == LUA_VTABLE, &((cast_u(o))->h)) 383 #define gco2p(o) check_exp((o)->tt == LUA_VPROTO, &((cast_u(o))->p)) 384 #define gco2th(o) check_exp((o)->tt == LUA_VTHREAD, &((cast_u(o))->th)) 385 #define gco2upv(o) check_exp((o)->tt == LUA_VUPVAL, &((cast_u(o))->upv)) 386 387 388 /* 389 ** macro to convert a Lua object into a GCObject 390 ** (The access to 'tt' tries to ensure that 'v' is actually a Lua object.) 391 */ 392 #define obj2gco(v) check_exp((v)->tt >= LUA_TSTRING, &(cast_u(v)->gc)) 393 394 395 /* actual number of total bytes allocated */ 396 #define gettotalbytes(g) cast(lu_mem, (g)->totalbytes + (g)->GCdebt) 397 398 LUAI_FUNC void luaE_setdebt (global_State *g, l_mem debt); 399 LUAI_FUNC void luaE_freethread (lua_State *L, lua_State *L1); 400 LUAI_FUNC CallInfo *luaE_extendCI (lua_State *L); 401 LUAI_FUNC void luaE_freeCI (lua_State *L); 402 LUAI_FUNC void luaE_shrinkCI (lua_State *L); 403 LUAI_FUNC void luaE_checkcstack (lua_State *L); 404 LUAI_FUNC void luaE_incCstack (lua_State *L); 405 LUAI_FUNC void luaE_warning (lua_State *L, const char *msg, int tocont); 406 LUAI_FUNC void luaE_warnerror (lua_State *L, const char *where); 407 LUAI_FUNC int luaE_resetthread (lua_State *L, int status); 408 409 410 #endif 411 412