1 /* 2 ** $Id: lstate.h,v 2.82 2012/07/02 13:37:04 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. 21 ** 22 ** Lua keeps most objects linked in list g->allgc. The link uses field 23 ** 'next' of the CommonHeader. 24 ** 25 ** Strings are kept in several lists headed by the array g->strt.hash. 26 ** 27 ** Open upvalues are not subject to independent garbage collection. They 28 ** are collected together with their respective threads. Lua keeps a 29 ** double-linked list with all open upvalues (g->uvhead) so that it can 30 ** mark objects referred by them. (They are always gray, so they must 31 ** be remarked in the atomic step. Usually their contents would be marked 32 ** when traversing the respective threads, but the thread may already be 33 ** dead, while the upvalue is still accessible through closures.) 34 ** 35 ** Objects with finalizers are kept in the list g->finobj. 36 ** 37 ** The list g->tobefnz links all objects being finalized. 38 39 */ 40 41 42 struct lua_longjmp; /* defined in ldo.c */ 43 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 #define KGC_GEN 2 /* generational collection */ 57 58 59 typedef struct stringtable { 60 GCObject **hash; 61 lu_int32 nuse; /* number of elements */ 62 int size; 63 } stringtable; 64 65 66 /* 67 ** information about a call 68 */ 69 typedef struct CallInfo { 70 StkId func; /* function index in the stack */ 71 StkId top; /* top for this function */ 72 struct CallInfo *previous, *next; /* dynamic call link */ 73 short nresults; /* expected number of results from this function */ 74 lu_byte callstatus; 75 ptrdiff_t extra; 76 union { 77 struct { /* only for Lua functions */ 78 StkId base; /* base for this function */ 79 const Instruction *savedpc; 80 } l; 81 struct { /* only for C functions */ 82 int ctx; /* context info. in case of yields */ 83 lua_CFunction k; /* continuation in case of yields */ 84 ptrdiff_t old_errfunc; 85 lu_byte old_allowhook; 86 lu_byte status; 87 } c; 88 } u; 89 } CallInfo; 90 91 92 /* 93 ** Bits in CallInfo status 94 */ 95 #define CIST_LUA (1<<0) /* call is running a Lua function */ 96 #define CIST_HOOKED (1<<1) /* call is running a debug hook */ 97 #define CIST_REENTRY (1<<2) /* call is running on same invocation of 98 luaV_execute of previous call */ 99 #define CIST_YIELDED (1<<3) /* call reentered after suspension */ 100 #define CIST_YPCALL (1<<4) /* call is a yieldable protected call */ 101 #define CIST_STAT (1<<5) /* call has an error status (pcall) */ 102 #define CIST_TAIL (1<<6) /* call was tail called */ 103 #define CIST_HOOKYIELD (1<<7) /* last hook called yielded */ 104 105 106 #define isLua(ci) ((ci)->callstatus & CIST_LUA) 107 108 109 /* 110 ** `global state', shared by all threads of this state 111 */ 112 typedef struct global_State { 113 lua_Alloc frealloc; /* function to reallocate memory */ 114 void *ud; /* auxiliary data to `frealloc' */ 115 lu_mem totalbytes; /* number of bytes currently allocated - GCdebt */ 116 l_mem GCdebt; /* bytes allocated not yet compensated by the collector */ 117 lu_mem GCmemtrav; /* memory traversed by the GC */ 118 lu_mem GCestimate; /* an estimate of the non-garbage memory in use */ 119 stringtable strt; /* hash table for strings */ 120 TValue l_registry; 121 unsigned int seed; /* randomized seed for hashes */ 122 lu_byte currentwhite; 123 lu_byte gcstate; /* state of garbage collector */ 124 lu_byte gckind; /* kind of GC running */ 125 lu_byte gcrunning; /* true if GC is running */ 126 int sweepstrgc; /* position of sweep in `strt' */ 127 GCObject *allgc; /* list of all collectable objects */ 128 GCObject *finobj; /* list of collectable objects with finalizers */ 129 GCObject **sweepgc; /* current position of sweep in list 'allgc' */ 130 GCObject **sweepfin; /* current position of sweep in list 'finobj' */ 131 GCObject *gray; /* list of gray objects */ 132 GCObject *grayagain; /* list of objects to be traversed atomically */ 133 GCObject *weak; /* list of tables with weak values */ 134 GCObject *ephemeron; /* list of ephemeron tables (weak keys) */ 135 GCObject *allweak; /* list of all-weak tables */ 136 GCObject *tobefnz; /* list of userdata to be GC */ 137 UpVal uvhead; /* head of double-linked list of all open upvalues */ 138 Mbuffer buff; /* temporary buffer for string concatenation */ 139 int gcpause; /* size of pause between successive GCs */ 140 int gcmajorinc; /* pause between major collections (only in gen. mode) */ 141 int gcstepmul; /* GC `granularity' */ 142 lua_CFunction panic; /* to be called in unprotected errors */ 143 struct lua_State *mainthread; 144 const lua_Number *version; /* pointer to version number */ 145 TString *memerrmsg; /* memory-error message */ 146 TString *tmname[TM_N]; /* array with tag-method names */ 147 struct Table *mt[LUA_NUMTAGS]; /* metatables for basic types */ 148 } global_State; 149 150 151 /* 152 ** `per thread' state 153 */ 154 struct lua_State { 155 CommonHeader; 156 lu_byte status; 157 StkId top; /* first free slot in the stack */ 158 global_State *l_G; 159 CallInfo *ci; /* call info for current function */ 160 const Instruction *oldpc; /* last pc traced */ 161 StkId stack_last; /* last free slot in the stack */ 162 StkId stack; /* stack base */ 163 int stacksize; 164 unsigned short nny; /* number of non-yieldable calls in stack */ 165 unsigned short nCcalls; /* number of nested C calls */ 166 lu_byte hookmask; 167 lu_byte allowhook; 168 int basehookcount; 169 int hookcount; 170 lua_Hook hook; 171 GCObject *openupval; /* list of open upvalues in this stack */ 172 GCObject *gclist; 173 struct lua_longjmp *errorJmp; /* current error recover point */ 174 ptrdiff_t errfunc; /* current error handling function (stack index) */ 175 CallInfo base_ci; /* CallInfo for first level (C calling Lua) */ 176 }; 177 178 179 #define G(L) (L->l_G) 180 181 182 /* 183 ** Union of all collectable objects 184 */ 185 union GCObject { 186 GCheader gch; /* common header */ 187 union TString ts; 188 union Udata u; 189 union Closure cl; 190 struct Table h; 191 struct Proto p; 192 struct UpVal uv; 193 struct lua_State th; /* thread */ 194 }; 195 196 197 #define gch(o) (&(o)->gch) 198 199 /* macros to convert a GCObject into a specific value */ 200 #define rawgco2ts(o) \ 201 check_exp(novariant((o)->gch.tt) == LUA_TSTRING, &((o)->ts)) 202 #define gco2ts(o) (&rawgco2ts(o)->tsv) 203 #define rawgco2u(o) check_exp((o)->gch.tt == LUA_TUSERDATA, &((o)->u)) 204 #define gco2u(o) (&rawgco2u(o)->uv) 205 #define gco2lcl(o) check_exp((o)->gch.tt == LUA_TLCL, &((o)->cl.l)) 206 #define gco2ccl(o) check_exp((o)->gch.tt == LUA_TCCL, &((o)->cl.c)) 207 #define gco2cl(o) \ 208 check_exp(novariant((o)->gch.tt) == LUA_TFUNCTION, &((o)->cl)) 209 #define gco2t(o) check_exp((o)->gch.tt == LUA_TTABLE, &((o)->h)) 210 #define gco2p(o) check_exp((o)->gch.tt == LUA_TPROTO, &((o)->p)) 211 #define gco2uv(o) check_exp((o)->gch.tt == LUA_TUPVAL, &((o)->uv)) 212 #define gco2th(o) check_exp((o)->gch.tt == LUA_TTHREAD, &((o)->th)) 213 214 /* macro to convert any Lua object into a GCObject */ 215 #define obj2gco(v) (cast(GCObject *, (v))) 216 217 218 /* actual number of total bytes allocated */ 219 #define gettotalbytes(g) ((g)->totalbytes + (g)->GCdebt) 220 221 LUAI_FUNC void luaE_setdebt (global_State *g, l_mem debt); 222 LUAI_FUNC void luaE_freethread (lua_State *L, lua_State *L1); 223 LUAI_FUNC CallInfo *luaE_extendCI (lua_State *L); 224 LUAI_FUNC void luaE_freeCI (lua_State *L); 225 226 227 #endif 228 229