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 #define BASIC_STACK_SIZE (2*LUA_MINSTACK) 146 147 #define stacksize(th) cast_int((th)->stack_last.p - (th)->stack.p) 148 149 150 /* kinds of Garbage Collection */ 151 #define KGC_INC 0 /* incremental gc */ 152 #define KGC_GEN 1 /* generational gc */ 153 154 155 typedef struct stringtable { 156 TString **hash; 157 int nuse; /* number of elements */ 158 int size; 159 } stringtable; 160 161 162 /* 163 ** Information about a call. 164 ** About union 'u': 165 ** - field 'l' is used only for Lua functions; 166 ** - field 'c' is used only for C functions. 167 ** About union 'u2': 168 ** - field 'funcidx' is used only by C functions while doing a 169 ** protected call; 170 ** - field 'nyield' is used only while a function is "doing" an 171 ** yield (from the yield until the next resume); 172 ** - field 'nres' is used only while closing tbc variables when 173 ** returning from a function; 174 ** - field 'transferinfo' is used only during call/returnhooks, 175 ** before the function starts or after it ends. 176 */ 177 struct CallInfo { 178 StkIdRel func; /* function index in the stack */ 179 StkIdRel top; /* top for this function */ 180 struct CallInfo *previous, *next; /* dynamic call link */ 181 union { 182 struct { /* only for Lua functions */ 183 const Instruction *savedpc; 184 volatile l_signalT trap; 185 int nextraargs; /* # of extra arguments in vararg functions */ 186 } l; 187 struct { /* only for C functions */ 188 lua_KFunction k; /* continuation in case of yields */ 189 ptrdiff_t old_errfunc; 190 lua_KContext ctx; /* context info. in case of yields */ 191 } c; 192 } u; 193 union { 194 int funcidx; /* called-function index */ 195 int nyield; /* number of values yielded */ 196 int nres; /* number of values returned */ 197 struct { /* info about transferred values (for call/return hooks) */ 198 unsigned short ftransfer; /* offset of first value transferred */ 199 unsigned short ntransfer; /* number of values transferred */ 200 } transferinfo; 201 } u2; 202 short nresults; /* expected number of results from this function */ 203 unsigned short callstatus; 204 }; 205 206 207 /* 208 ** Bits in CallInfo status 209 */ 210 #define CIST_OAH (1<<0) /* original value of 'allowhook' */ 211 #define CIST_C (1<<1) /* call is running a C function */ 212 #define CIST_FRESH (1<<2) /* call is on a fresh "luaV_execute" frame */ 213 #define CIST_HOOKED (1<<3) /* call is running a debug hook */ 214 #define CIST_YPCALL (1<<4) /* doing a yieldable protected call */ 215 #define CIST_TAIL (1<<5) /* call was tail called */ 216 #define CIST_HOOKYIELD (1<<6) /* last hook called yielded */ 217 #define CIST_FIN (1<<7) /* function "called" a finalizer */ 218 #define CIST_TRAN (1<<8) /* 'ci' has transfer information */ 219 #define CIST_CLSRET (1<<9) /* function is closing tbc variables */ 220 /* Bits 10-12 are used for CIST_RECST (see below) */ 221 #define CIST_RECST 10 222 #if defined(LUA_COMPAT_LT_LE) 223 #define CIST_LEQ (1<<13) /* using __lt for __le */ 224 #endif 225 226 227 /* 228 ** Field CIST_RECST stores the "recover status", used to keep the error 229 ** status while closing to-be-closed variables in coroutines, so that 230 ** Lua can correctly resume after an yield from a __close method called 231 ** because of an error. (Three bits are enough for error status.) 232 */ 233 #define getcistrecst(ci) (((ci)->callstatus >> CIST_RECST) & 7) 234 #define setcistrecst(ci,st) \ 235 check_exp(((st) & 7) == (st), /* status must fit in three bits */ \ 236 ((ci)->callstatus = ((ci)->callstatus & ~(7 << CIST_RECST)) \ 237 | ((st) << CIST_RECST))) 238 239 240 /* active function is a Lua function */ 241 #define isLua(ci) (!((ci)->callstatus & CIST_C)) 242 243 /* call is running Lua code (not a hook) */ 244 #define isLuacode(ci) (!((ci)->callstatus & (CIST_C | CIST_HOOKED))) 245 246 /* assume that CIST_OAH has offset 0 and that 'v' is strictly 0/1 */ 247 #define setoah(st,v) ((st) = ((st) & ~CIST_OAH) | (v)) 248 #define getoah(st) ((st) & CIST_OAH) 249 250 251 /* 252 ** 'global state', shared by all threads of this state 253 */ 254 typedef struct global_State { 255 lua_Alloc frealloc; /* function to reallocate memory */ 256 void *ud; /* auxiliary data to 'frealloc' */ 257 l_mem totalbytes; /* number of bytes currently allocated - GCdebt */ 258 l_mem GCdebt; /* bytes allocated not yet compensated by the collector */ 259 lu_mem GCestimate; /* an estimate of the non-garbage memory in use */ 260 lu_mem lastatomic; /* see function 'genstep' in file 'lgc.c' */ 261 stringtable strt; /* hash table for strings */ 262 TValue l_registry; 263 TValue nilvalue; /* a nil value */ 264 unsigned int seed; /* randomized seed for hashes */ 265 lu_byte currentwhite; 266 lu_byte gcstate; /* state of garbage collector */ 267 lu_byte gckind; /* kind of GC running */ 268 lu_byte gcstopem; /* stops emergency collections */ 269 lu_byte genminormul; /* control for minor generational collections */ 270 lu_byte genmajormul; /* control for major generational collections */ 271 lu_byte gcstp; /* control whether GC is running */ 272 lu_byte gcemergency; /* true if this is an emergency collection */ 273 lu_byte gcpause; /* size of pause between successive GCs */ 274 lu_byte gcstepmul; /* GC "speed" */ 275 lu_byte gcstepsize; /* (log2 of) GC granularity */ 276 GCObject *allgc; /* list of all collectable objects */ 277 GCObject **sweepgc; /* current position of sweep in list */ 278 GCObject *finobj; /* list of collectable objects with finalizers */ 279 GCObject *gray; /* list of gray objects */ 280 GCObject *grayagain; /* list of objects to be traversed atomically */ 281 GCObject *weak; /* list of tables with weak values */ 282 GCObject *ephemeron; /* list of ephemeron tables (weak keys) */ 283 GCObject *allweak; /* list of all-weak tables */ 284 GCObject *tobefnz; /* list of userdata to be GC */ 285 GCObject *fixedgc; /* list of objects not to be collected */ 286 /* fields for generational collector */ 287 GCObject *survival; /* start of objects that survived one GC cycle */ 288 GCObject *old1; /* start of old1 objects */ 289 GCObject *reallyold; /* objects more than one cycle old ("really old") */ 290 GCObject *firstold1; /* first OLD1 object in the list (if any) */ 291 GCObject *finobjsur; /* list of survival objects with finalizers */ 292 GCObject *finobjold1; /* list of old1 objects with finalizers */ 293 GCObject *finobjrold; /* list of really old objects with finalizers */ 294 struct lua_State *twups; /* list of threads with open upvalues */ 295 lua_CFunction panic; /* to be called in unprotected errors */ 296 struct lua_State *mainthread; 297 TString *memerrmsg; /* message for memory-allocation errors */ 298 TString *tmname[TM_N]; /* array with tag-method names */ 299 struct Table *mt[LUA_NUMTYPES]; /* metatables for basic types */ 300 TString *strcache[STRCACHE_N][STRCACHE_M]; /* cache for strings in API */ 301 lua_WarnFunction warnf; /* warning function */ 302 void *ud_warn; /* auxiliary data to 'warnf' */ 303 } global_State; 304 305 306 /* 307 ** 'per thread' state 308 */ 309 struct lua_State { 310 CommonHeader; 311 lu_byte status; 312 lu_byte allowhook; 313 unsigned short nci; /* number of items in 'ci' list */ 314 StkIdRel top; /* first free slot in the stack */ 315 global_State *l_G; 316 CallInfo *ci; /* call info for current function */ 317 StkIdRel stack_last; /* end of stack (last element + 1) */ 318 StkIdRel stack; /* stack base */ 319 UpVal *openupval; /* list of open upvalues in this stack */ 320 StkIdRel tbclist; /* list of to-be-closed variables */ 321 GCObject *gclist; 322 struct lua_State *twups; /* list of threads with open upvalues */ 323 struct lua_longjmp *errorJmp; /* current error recover point */ 324 CallInfo base_ci; /* CallInfo for first level (C calling Lua) */ 325 volatile lua_Hook hook; 326 ptrdiff_t errfunc; /* current error handling function (stack index) */ 327 l_uint32 nCcalls; /* number of nested (non-yieldable | C) calls */ 328 int oldpc; /* last pc traced */ 329 int basehookcount; 330 int hookcount; 331 volatile l_signalT hookmask; 332 }; 333 334 335 #define G(L) (L->l_G) 336 337 /* 338 ** 'g->nilvalue' being a nil value flags that the state was completely 339 ** build. 340 */ 341 #define completestate(g) ttisnil(&g->nilvalue) 342 343 344 /* 345 ** Union of all collectable objects (only for conversions) 346 ** ISO C99, 6.5.2.3 p.5: 347 ** "if a union contains several structures that share a common initial 348 ** sequence [...], and if the union object currently contains one 349 ** of these structures, it is permitted to inspect the common initial 350 ** part of any of them anywhere that a declaration of the complete type 351 ** of the union is visible." 352 */ 353 union GCUnion { 354 GCObject gc; /* common header */ 355 struct TString ts; 356 struct Udata u; 357 union Closure cl; 358 struct Table h; 359 struct Proto p; 360 struct lua_State th; /* thread */ 361 struct UpVal upv; 362 }; 363 364 365 /* 366 ** ISO C99, 6.7.2.1 p.14: 367 ** "A pointer to a union object, suitably converted, points to each of 368 ** its members [...], and vice versa." 369 */ 370 #define cast_u(o) cast(union GCUnion *, (o)) 371 372 /* macros to convert a GCObject into a specific value */ 373 #define gco2ts(o) \ 374 check_exp(novariant((o)->tt) == LUA_TSTRING, &((cast_u(o))->ts)) 375 #define gco2u(o) check_exp((o)->tt == LUA_VUSERDATA, &((cast_u(o))->u)) 376 #define gco2lcl(o) check_exp((o)->tt == LUA_VLCL, &((cast_u(o))->cl.l)) 377 #define gco2ccl(o) check_exp((o)->tt == LUA_VCCL, &((cast_u(o))->cl.c)) 378 #define gco2cl(o) \ 379 check_exp(novariant((o)->tt) == LUA_TFUNCTION, &((cast_u(o))->cl)) 380 #define gco2t(o) check_exp((o)->tt == LUA_VTABLE, &((cast_u(o))->h)) 381 #define gco2p(o) check_exp((o)->tt == LUA_VPROTO, &((cast_u(o))->p)) 382 #define gco2th(o) check_exp((o)->tt == LUA_VTHREAD, &((cast_u(o))->th)) 383 #define gco2upv(o) check_exp((o)->tt == LUA_VUPVAL, &((cast_u(o))->upv)) 384 385 386 /* 387 ** macro to convert a Lua object into a GCObject 388 ** (The access to 'tt' tries to ensure that 'v' is actually a Lua object.) 389 */ 390 #define obj2gco(v) check_exp((v)->tt >= LUA_TSTRING, &(cast_u(v)->gc)) 391 392 393 /* actual number of total bytes allocated */ 394 #define gettotalbytes(g) cast(lu_mem, (g)->totalbytes + (g)->GCdebt) 395 396 LUAI_FUNC void luaE_setdebt (global_State *g, l_mem debt); 397 LUAI_FUNC void luaE_freethread (lua_State *L, lua_State *L1); 398 LUAI_FUNC CallInfo *luaE_extendCI (lua_State *L); 399 LUAI_FUNC void luaE_freeCI (lua_State *L); 400 LUAI_FUNC void luaE_shrinkCI (lua_State *L); 401 LUAI_FUNC void luaE_checkcstack (lua_State *L); 402 LUAI_FUNC void luaE_incCstack (lua_State *L); 403 LUAI_FUNC void luaE_warning (lua_State *L, const char *msg, int tocont); 404 LUAI_FUNC void luaE_warnerror (lua_State *L, const char *where); 405 LUAI_FUNC int luaE_resetthread (lua_State *L, int status); 406 407 408 #endif 409 410