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