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 */ 16typedef 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 124struct 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 157typedef 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*/ 179struct 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*/ 256typedef 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*/ 311struct 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*/ 355union 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 398LUAI_FUNC void luaE_setdebt (global_State *g, l_mem debt); 399LUAI_FUNC void luaE_freethread (lua_State *L, lua_State *L1); 400LUAI_FUNC CallInfo *luaE_extendCI (lua_State *L); 401LUAI_FUNC void luaE_freeCI (lua_State *L); 402LUAI_FUNC void luaE_shrinkCI (lua_State *L); 403LUAI_FUNC void luaE_checkcstack (lua_State *L); 404LUAI_FUNC void luaE_incCstack (lua_State *L); 405LUAI_FUNC void luaE_warning (lua_State *L, const char *msg, int tocont); 406LUAI_FUNC void luaE_warnerror (lua_State *L, const char *where); 407LUAI_FUNC int luaE_resetthread (lua_State *L, int status); 408 409 410#endif 411 412