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 */ 14typedef 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 122struct 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 155typedef 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*/ 177struct 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*/ 254typedef 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*/ 309struct 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*/ 353union 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 396LUAI_FUNC void luaE_setdebt (global_State *g, l_mem debt); 397LUAI_FUNC void luaE_freethread (lua_State *L, lua_State *L1); 398LUAI_FUNC CallInfo *luaE_extendCI (lua_State *L); 399LUAI_FUNC void luaE_freeCI (lua_State *L); 400LUAI_FUNC void luaE_shrinkCI (lua_State *L); 401LUAI_FUNC void luaE_checkcstack (lua_State *L); 402LUAI_FUNC void luaE_incCstack (lua_State *L); 403LUAI_FUNC void luaE_warning (lua_State *L, const char *msg, int tocont); 404LUAI_FUNC void luaE_warnerror (lua_State *L, const char *where); 405LUAI_FUNC int luaE_resetthread (lua_State *L, int status); 406 407 408#endif 409 410