1 /* 2 ** $Id: lstate.h,v 2.133 2016/12/22 13:08:50 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 */ 31 32 33 struct lua_longjmp; /* defined in ldo.c */ 34 35 36 /* 37 ** Atomic type (relative to signals) to better ensure that 'lua_sethook' 38 ** is thread safe 39 */ 40 #if !defined(l_signalT) 41 #include <signal.h> 42 #define l_signalT sig_atomic_t 43 #endif 44 45 46 /* extra stack space to handle TM calls and some other extras */ 47 #define EXTRA_STACK 5 48 49 50 #define BASIC_STACK_SIZE (2*LUA_MINSTACK) 51 52 53 /* kinds of Garbage Collection */ 54 #define KGC_NORMAL 0 55 #define KGC_EMERGENCY 1 /* gc was forced by an allocation failure */ 56 57 58 typedef struct stringtable { 59 TString **hash; 60 int nuse; /* number of elements */ 61 int size; 62 } stringtable; 63 64 65 /* 66 ** Information about a call. 67 ** When a thread yields, 'func' is adjusted to pretend that the 68 ** top function has only the yielded values in its stack; in that 69 ** case, the actual 'func' value is saved in field 'extra'. 70 ** When a function calls another with a continuation, 'extra' keeps 71 ** the function index so that, in case of errors, the continuation 72 ** function can be called with the correct top. 73 */ 74 typedef struct CallInfo { 75 StkId func; /* function index in the stack */ 76 StkId top; /* top for this function */ 77 struct CallInfo *previous, *next; /* dynamic call link */ 78 union { 79 struct { /* only for Lua functions */ 80 StkId base; /* base for this function */ 81 const Instruction *savedpc; 82 } l; 83 struct { /* only for C functions */ 84 lua_KFunction k; /* continuation in case of yields */ 85 ptrdiff_t old_errfunc; 86 lua_KContext ctx; /* context info. in case of yields */ 87 } c; 88 } u; 89 ptrdiff_t extra; 90 short nresults; /* expected number of results from this function */ 91 unsigned short callstatus; 92 } CallInfo; 93 94 95 /* 96 ** Bits in CallInfo status 97 */ 98 #define CIST_OAH (1<<0) /* original value of 'allowhook' */ 99 #define CIST_LUA (1<<1) /* call is running a Lua function */ 100 #define CIST_HOOKED (1<<2) /* call is running a debug hook */ 101 #define CIST_FRESH (1<<3) /* call is running on a fresh invocation 102 of luaV_execute */ 103 #define CIST_YPCALL (1<<4) /* call is a yieldable protected call */ 104 #define CIST_TAIL (1<<5) /* call was tail called */ 105 #define CIST_HOOKYIELD (1<<6) /* last hook called yielded */ 106 #define CIST_LEQ (1<<7) /* using __lt for __le */ 107 #define CIST_FIN (1<<8) /* call is running a finalizer */ 108 109 #define isLua(ci) ((ci)->callstatus & CIST_LUA) 110 111 /* assume that CIST_OAH has offset 0 and that 'v' is strictly 0/1 */ 112 #define setoah(st,v) ((st) = ((st) & ~CIST_OAH) | (v)) 113 #define getoah(st) ((st) & CIST_OAH) 114 115 116 /* 117 ** 'global state', shared by all threads of this state 118 */ 119 typedef struct global_State { 120 lua_Alloc frealloc; /* function to reallocate memory */ 121 void *ud; /* auxiliary data to 'frealloc' */ 122 l_mem totalbytes; /* number of bytes currently allocated - GCdebt */ 123 l_mem GCdebt; /* bytes allocated not yet compensated by the collector */ 124 lu_mem GCmemtrav; /* memory traversed by the GC */ 125 lu_mem GCestimate; /* an estimate of the non-garbage memory in use */ 126 stringtable strt; /* hash table for strings */ 127 TValue l_registry; 128 unsigned int seed; /* randomized seed for hashes */ 129 lu_byte currentwhite; 130 lu_byte gcstate; /* state of garbage collector */ 131 lu_byte gckind; /* kind of GC running */ 132 lu_byte gcrunning; /* true if GC is running */ 133 GCObject *allgc; /* list of all collectable objects */ 134 GCObject **sweepgc; /* current position of sweep in list */ 135 GCObject *finobj; /* list of collectable objects with finalizers */ 136 GCObject *gray; /* list of gray objects */ 137 GCObject *grayagain; /* list of objects to be traversed atomically */ 138 GCObject *weak; /* list of tables with weak values */ 139 GCObject *ephemeron; /* list of ephemeron tables (weak keys) */ 140 GCObject *allweak; /* list of all-weak tables */ 141 GCObject *tobefnz; /* list of userdata to be GC */ 142 GCObject *fixedgc; /* list of objects not to be collected */ 143 struct lua_State *twups; /* list of threads with open upvalues */ 144 unsigned int gcfinnum; /* number of finalizers to call in each GC step */ 145 int gcpause; /* size of pause between successive GCs */ 146 int gcstepmul; /* GC 'granularity' */ 147 lua_CFunction panic; /* to be called in unprotected errors */ 148 struct lua_State *mainthread; 149 const lua_Number *version; /* pointer to version number */ 150 TString *memerrmsg; /* memory-error message */ 151 TString *tmname[TM_N]; /* array with tag-method names */ 152 struct Table *mt[LUA_NUMTAGS]; /* metatables for basic types */ 153 TString *strcache[STRCACHE_N][STRCACHE_M]; /* cache for strings in API */ 154 } global_State; 155 156 157 /* 158 ** 'per thread' state 159 */ 160 struct lua_State { 161 CommonHeader; 162 unsigned short nci; /* number of items in 'ci' list */ 163 lu_byte status; 164 StkId top; /* first free slot in the stack */ 165 global_State *l_G; 166 CallInfo *ci; /* call info for current function */ 167 const Instruction *oldpc; /* last pc traced */ 168 StkId stack_last; /* last free slot in the stack */ 169 StkId stack; /* stack base */ 170 UpVal *openupval; /* list of open upvalues in this stack */ 171 GCObject *gclist; 172 struct lua_State *twups; /* list of threads with open upvalues */ 173 struct lua_longjmp *errorJmp; /* current error recover point */ 174 CallInfo base_ci; /* CallInfo for first level (C calling Lua) */ 175 volatile lua_Hook hook; 176 ptrdiff_t errfunc; /* current error handling function (stack index) */ 177 int stacksize; 178 int basehookcount; 179 int hookcount; 180 unsigned short nny; /* number of non-yieldable calls in stack */ 181 unsigned short nCcalls; /* number of nested C calls */ 182 l_signalT hookmask; 183 lu_byte allowhook; 184 }; 185 186 187 #define G(L) (L->l_G) 188 189 190 /* 191 ** Union of all collectable objects (only for conversions) 192 */ 193 union GCUnion { 194 GCObject gc; /* common header */ 195 struct TString ts; 196 struct Udata u; 197 union Closure cl; 198 struct Table h; 199 struct Proto p; 200 struct lua_State th; /* thread */ 201 }; 202 203 204 #define cast_u(o) cast(union GCUnion *, (o)) 205 206 /* macros to convert a GCObject into a specific value */ 207 #define gco2ts(o) \ 208 check_exp(novariant((o)->tt) == LUA_TSTRING, &((cast_u(o))->ts)) 209 #define gco2u(o) check_exp((o)->tt == LUA_TUSERDATA, &((cast_u(o))->u)) 210 #define gco2lcl(o) check_exp((o)->tt == LUA_TLCL, &((cast_u(o))->cl.l)) 211 #define gco2ccl(o) check_exp((o)->tt == LUA_TCCL, &((cast_u(o))->cl.c)) 212 #define gco2cl(o) \ 213 check_exp(novariant((o)->tt) == LUA_TFUNCTION, &((cast_u(o))->cl)) 214 #define gco2t(o) check_exp((o)->tt == LUA_TTABLE, &((cast_u(o))->h)) 215 #define gco2p(o) check_exp((o)->tt == LUA_TPROTO, &((cast_u(o))->p)) 216 #define gco2th(o) check_exp((o)->tt == LUA_TTHREAD, &((cast_u(o))->th)) 217 218 219 /* macro to convert a Lua object into a GCObject */ 220 #define obj2gco(v) \ 221 check_exp(novariant((v)->tt) < LUA_TDEADKEY, (&(cast_u(v)->gc))) 222 223 224 /* actual number of total bytes allocated */ 225 #define gettotalbytes(g) cast(lu_mem, (g)->totalbytes + (g)->GCdebt) 226 227 LUAI_FUNC void luaE_setdebt (global_State *g, l_mem debt); 228 LUAI_FUNC void luaE_freethread (lua_State *L, lua_State *L1); 229 LUAI_FUNC CallInfo *luaE_extendCI (lua_State *L); 230 LUAI_FUNC void luaE_freeCI (lua_State *L); 231 LUAI_FUNC void luaE_shrinkCI (lua_State *L); 232 233 234 #endif 235 236