1 /* 2 ** $Id: lstate.h,v 2.133.1.1 2017/04/19 17:39:34 roberto Exp $ 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 19 ** Some notes about garbage-collected objects: All objects in Lua must 20 ** be kept somehow accessible until being freed, so all objects always 21 ** belong to one (and only one) of these lists, using field 'next' of 22 ** the 'CommonHeader' for the link: 23 ** 24 ** 'allgc': all objects not marked for finalization; 25 ** 'finobj': all objects marked for finalization; 26 ** 'tobefnz': all objects ready to be finalized; 27 ** 'fixedgc': all objects that are not to be collected (currently 28 ** only small strings, such as reserved words). 29 ** 30 ** Moreover, there is another set of lists that control gray objects. 31 ** These lists are linked by fields 'gclist'. (All objects that 32 ** can become gray have such a field. The field is not the same 33 ** in all objects, but it always has this name.) Any gray object 34 ** must belong to one of these lists, and all objects in these lists 35 ** must be gray: 36 ** 37 ** 'gray': regular gray objects, still waiting to be visited. 38 ** 'grayagain': objects that must be revisited at the atomic phase. 39 ** That includes 40 ** - black objects got in a write barrier; 41 ** - all kinds of weak tables during propagation phase; 42 ** - all threads. 43 ** 'weak': tables with weak values to be cleared; 44 ** 'ephemeron': ephemeron tables with white->white entries; 45 ** 'allweak': tables with weak keys and/or weak values to be cleared. 46 ** The last three lists are used only during the atomic phase. 47 48 */ 49 50 51 struct lua_longjmp; /* defined in ldo.c */ 52 53 54 /* 55 ** Atomic type (relative to signals) to better ensure that 'lua_sethook' 56 ** is thread safe 57 */ 58 #if !defined(l_signalT) 59 #include <signal.h> 60 #define l_signalT sig_atomic_t 61 #endif 62 63 64 /* extra stack space to handle TM calls and some other extras */ 65 #define EXTRA_STACK 5 66 67 68 #define BASIC_STACK_SIZE (2*LUA_MINSTACK) 69 70 71 /* kinds of Garbage Collection */ 72 #define KGC_NORMAL 0 73 #define KGC_EMERGENCY 1 /* gc was forced by an allocation failure */ 74 75 76 typedef struct stringtable { 77 TString **hash; 78 int nuse; /* number of elements */ 79 int size; 80 } stringtable; 81 82 83 /* 84 ** Information about a call. 85 ** When a thread yields, 'func' is adjusted to pretend that the 86 ** top function has only the yielded values in its stack; in that 87 ** case, the actual 'func' value is saved in field 'extra'. 88 ** When a function calls another with a continuation, 'extra' keeps 89 ** the function index so that, in case of errors, the continuation 90 ** function can be called with the correct top. 91 */ 92 typedef struct CallInfo { 93 StkId func; /* function index in the stack */ 94 StkId top; /* top for this function */ 95 struct CallInfo *previous, *next; /* dynamic call link */ 96 union { 97 struct { /* only for Lua functions */ 98 StkId base; /* base for this function */ 99 const Instruction *savedpc; 100 } l; 101 struct { /* only for C functions */ 102 lua_KFunction k; /* continuation in case of yields */ 103 ptrdiff_t old_errfunc; 104 lua_KContext ctx; /* context info. in case of yields */ 105 } c; 106 } u; 107 ptrdiff_t extra; 108 short nresults; /* expected number of results from this function */ 109 unsigned short callstatus; 110 } CallInfo; 111 112 113 /* 114 ** Bits in CallInfo status 115 */ 116 #define CIST_OAH (1<<0) /* original value of 'allowhook' */ 117 #define CIST_LUA (1<<1) /* call is running a Lua function */ 118 #define CIST_HOOKED (1<<2) /* call is running a debug hook */ 119 #define CIST_FRESH (1<<3) /* call is running on a fresh invocation 120 of luaV_execute */ 121 #define CIST_YPCALL (1<<4) /* call is a yieldable protected call */ 122 #define CIST_TAIL (1<<5) /* call was tail called */ 123 #define CIST_HOOKYIELD (1<<6) /* last hook called yielded */ 124 #define CIST_LEQ (1<<7) /* using __lt for __le */ 125 #define CIST_FIN (1<<8) /* call is running a finalizer */ 126 127 #define isLua(ci) ((ci)->callstatus & CIST_LUA) 128 129 /* assume that CIST_OAH has offset 0 and that 'v' is strictly 0/1 */ 130 #define setoah(st,v) ((st) = ((st) & ~CIST_OAH) | (v)) 131 #define getoah(st) ((st) & CIST_OAH) 132 133 134 /* 135 ** 'global state', shared by all threads of this state 136 */ 137 typedef struct global_State { 138 lua_Alloc frealloc; /* function to reallocate memory */ 139 void *ud; /* auxiliary data to 'frealloc' */ 140 l_mem totalbytes; /* number of bytes currently allocated - GCdebt */ 141 l_mem GCdebt; /* bytes allocated not yet compensated by the collector */ 142 lu_mem GCmemtrav; /* memory traversed by the GC */ 143 lu_mem GCestimate; /* an estimate of the non-garbage memory in use */ 144 stringtable strt; /* hash table for strings */ 145 TValue l_registry; 146 unsigned int seed; /* randomized seed for hashes */ 147 lu_byte currentwhite; 148 lu_byte gcstate; /* state of garbage collector */ 149 lu_byte gckind; /* kind of GC running */ 150 lu_byte gcrunning; /* true if GC is running */ 151 GCObject *allgc; /* list of all collectable objects */ 152 GCObject **sweepgc; /* current position of sweep in list */ 153 GCObject *finobj; /* list of collectable objects with finalizers */ 154 GCObject *gray; /* list of gray objects */ 155 GCObject *grayagain; /* list of objects to be traversed atomically */ 156 GCObject *weak; /* list of tables with weak values */ 157 GCObject *ephemeron; /* list of ephemeron tables (weak keys) */ 158 GCObject *allweak; /* list of all-weak tables */ 159 GCObject *tobefnz; /* list of userdata to be GC */ 160 GCObject *fixedgc; /* list of objects not to be collected */ 161 struct lua_State *twups; /* list of threads with open upvalues */ 162 unsigned int gcfinnum; /* number of finalizers to call in each GC step */ 163 int gcpause; /* size of pause between successive GCs */ 164 int gcstepmul; /* GC 'granularity' */ 165 lua_CFunction panic; /* to be called in unprotected errors */ 166 struct lua_State *mainthread; 167 const lua_Number *version; /* pointer to version number */ 168 TString *memerrmsg; /* memory-error message */ 169 TString *tmname[TM_N]; /* array with tag-method names */ 170 struct Table *mt[LUA_NUMTAGS]; /* metatables for basic types */ 171 TString *strcache[STRCACHE_N][STRCACHE_M]; /* cache for strings in API */ 172 } global_State; 173 174 175 /* 176 ** 'per thread' state 177 */ 178 struct lua_State { 179 CommonHeader; 180 unsigned short nci; /* number of items in 'ci' list */ 181 lu_byte status; 182 StkId top; /* first free slot in the stack */ 183 global_State *l_G; 184 CallInfo *ci; /* call info for current function */ 185 const Instruction *oldpc; /* last pc traced */ 186 StkId stack_last; /* last free slot in the stack */ 187 StkId stack; /* stack base */ 188 UpVal *openupval; /* list of open upvalues in this stack */ 189 GCObject *gclist; 190 struct lua_State *twups; /* list of threads with open upvalues */ 191 struct lua_longjmp *errorJmp; /* current error recover point */ 192 CallInfo base_ci; /* CallInfo for first level (C calling Lua) */ 193 volatile lua_Hook hook; 194 ptrdiff_t errfunc; /* current error handling function (stack index) */ 195 int stacksize; 196 int basehookcount; 197 int hookcount; 198 unsigned short nny; /* number of non-yieldable calls in stack */ 199 unsigned short nCcalls; /* number of nested C calls */ 200 l_signalT hookmask; 201 lu_byte allowhook; 202 }; 203 204 205 #define G(L) (L->l_G) 206 207 208 /* 209 ** Union of all collectable objects (only for conversions) 210 */ 211 union GCUnion { 212 GCObject gc; /* common header */ 213 struct TString ts; 214 struct Udata u; 215 union Closure cl; 216 struct Table h; 217 struct Proto p; 218 struct lua_State th; /* thread */ 219 }; 220 221 222 #define cast_u(o) cast(union GCUnion *, (o)) 223 224 /* macros to convert a GCObject into a specific value */ 225 #define gco2ts(o) \ 226 check_exp(novariant((o)->tt) == LUA_TSTRING, &((cast_u(o))->ts)) 227 #define gco2u(o) check_exp((o)->tt == LUA_TUSERDATA, &((cast_u(o))->u)) 228 #define gco2lcl(o) check_exp((o)->tt == LUA_TLCL, &((cast_u(o))->cl.l)) 229 #define gco2ccl(o) check_exp((o)->tt == LUA_TCCL, &((cast_u(o))->cl.c)) 230 #define gco2cl(o) \ 231 check_exp(novariant((o)->tt) == LUA_TFUNCTION, &((cast_u(o))->cl)) 232 #define gco2t(o) check_exp((o)->tt == LUA_TTABLE, &((cast_u(o))->h)) 233 #define gco2p(o) check_exp((o)->tt == LUA_TPROTO, &((cast_u(o))->p)) 234 #define gco2th(o) check_exp((o)->tt == LUA_TTHREAD, &((cast_u(o))->th)) 235 236 237 /* macro to convert a Lua object into a GCObject */ 238 #define obj2gco(v) \ 239 check_exp(novariant((v)->tt) < LUA_TDEADKEY, (&(cast_u(v)->gc))) 240 241 242 /* actual number of total bytes allocated */ 243 #define gettotalbytes(g) cast(lu_mem, (g)->totalbytes + (g)->GCdebt) 244 245 LUAI_FUNC void luaE_setdebt (global_State *g, l_mem debt); 246 LUAI_FUNC void luaE_freethread (lua_State *L, lua_State *L1); 247 LUAI_FUNC CallInfo *luaE_extendCI (lua_State *L); 248 LUAI_FUNC void luaE_freeCI (lua_State *L); 249 LUAI_FUNC void luaE_shrinkCI (lua_State *L); 250 251 252 #endif 253 254