external/mit/lua/dist/src/lstate.h

   1 /*      $NetBSD: lstate.h,v 1.4 2015/10/08 13:21:00 mbalmer Exp $       */
   2
   3 /*
   4 ** Id: lstate.h,v 2.122 2015/06/01 16:34:37 roberto Exp
   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 #include "lobject.h"
  15 #include "ltm.h"
  16 #include "lzio.h"
  17
  18
  19 /*
  20
  21 ** Some notes about garbage-collected objects: All objects in Lua must
  22 ** be kept somehow accessible until being freed, so all objects always
  23 ** belong to one (and only one) of these lists, using field 'next' of
  24 ** the 'CommonHeader' for the link:
  25 **
  26 ** 'allgc': all objects not marked for finalization;
  27 ** 'finobj': all objects marked for finalization;
  28 ** 'tobefnz': all objects ready to be finalized;
  29 ** 'fixedgc': all objects that are not to be collected (currently
  30 ** only small strings, such as reserved words).
  31
  32 */
  33
  34
  35 struct lua_longjmp;  /* defined in ldo.c */
  36
  37
  38
  39 /* extra stack space to handle TM calls and some other extras */
  40 #define EXTRA_STACK   5
  41
  42
  43 #define BASIC_STACK_SIZE        (2*LUA_MINSTACK)
  44
  45
  46 /* kinds of Garbage Collection */
  47 #define KGC_NORMAL      0
  48 #define KGC_EMERGENCY   1       /* gc was forced by an allocation failure */
  49
  50
  51 typedef struct stringtable {
  52   TString **hash;
  53   int nuse;  /* number of elements */
  54   int size;
  55 } stringtable;
  56
  57
  58 /*
  59 ** Information about a call.
  60 ** When a thread yields, 'func' is adjusted to pretend that the
  61 ** top function has only the yielded values in its stack; in that
  62 ** case, the actual 'func' value is saved in field 'extra'.
  63 ** When a function calls another with a continuation, 'extra' keeps
  64 ** the function index so that, in case of errors, the continuation
  65 ** function can be called with the correct top.
  66 */
  67 typedef struct CallInfo {
  68   StkId func;  /* function index in the stack */
  69   StkId top;  /* top for this function */
  70   struct CallInfo *previous, *next;  /* dynamic call link */
  71   union {
  72     struct {  /* only for Lua functions */
  73       StkId base;  /* base for this function */
  74       const Instruction *savedpc;
  75     } l;
  76     struct {  /* only for C functions */
  77       lua_KFunction k;  /* continuation in case of yields */
  78       ptrdiff_t old_errfunc;
  79       lua_KContext ctx;  /* context info. in case of yields */
  80     } c;
  81   } u;
  82   ptrdiff_t extra;
  83   short nresults;  /* expected number of results from this function */
  84   lu_byte callstatus;
  85 } CallInfo;
  86
  87
  88 /*
  89 ** Bits in CallInfo status
  90 */
  91 #define CIST_OAH        (1<<0)  /* original value of 'allowhook' */
  92 #define CIST_LUA        (1<<1)  /* call is running a Lua function */
  93 #define CIST_HOOKED     (1<<2)  /* call is running a debug hook */
  94 #define CIST_REENTRY    (1<<3)  /* call is running on same invocation of
  95                                    luaV_execute of previous call */
  96 #define CIST_YPCALL     (1<<4)  /* call is a yieldable protected call */
  97 #define CIST_TAIL       (1<<5)  /* call was tail called */
  98 #define CIST_HOOKYIELD  (1<<6)  /* last hook called yielded */
  99 #define CIST_LEQ        (1<<7)  /* using __lt for __le */
 100
 101 #define isLua(ci)       ((ci)->callstatus & CIST_LUA)
 102
 103 /* assume that CIST_OAH has offset 0 and that 'v' is strictly 0/1 */
 104 #define setoah(st,v)    ((st) = ((st) & ~CIST_OAH) | (v))
 105 #define getoah(st)      ((st) & CIST_OAH)
 106
 107
 108 /*
 109 ** 'global state', shared by all threads of this state
 110 */
 111 typedef struct global_State {
 112   lua_Alloc frealloc;  /* function to reallocate memory */
 113   void *ud;         /* auxiliary data to 'frealloc' */
 114   lu_mem totalbytes;  /* number of bytes currently allocated - GCdebt */
 115   l_mem GCdebt;  /* bytes allocated not yet compensated by the collector */
 116   lu_mem GCmemtrav;  /* memory traversed by the GC */
 117   lu_mem GCestimate;  /* an estimate of the non-garbage memory in use */
 118   stringtable strt;  /* hash table for strings */
 119   TValue l_registry;
 120   unsigned int seed;  /* randomized seed for hashes */
 121   lu_byte currentwhite;
 122   lu_byte gcstate;  /* state of garbage collector */
 123   lu_byte gckind;  /* kind of GC running */
 124   lu_byte gcrunning;  /* true if GC is running */
 125   GCObject *allgc;  /* list of all collectable objects */
 126   GCObject **sweepgc;  /* current position of sweep in list */
 127   GCObject *finobj;  /* list of collectable objects with finalizers */
 128   GCObject *gray;  /* list of gray objects */
 129   GCObject *grayagain;  /* list of objects to be traversed atomically */
 130   GCObject *weak;  /* list of tables with weak values */
 131   GCObject *ephemeron;  /* list of ephemeron tables (weak keys) */
 132   GCObject *allweak;  /* list of all-weak tables */
 133   GCObject *tobefnz;  /* list of userdata to be GC */
 134   GCObject *fixedgc;  /* list of objects not to be collected */
 135   struct lua_State *twups;  /* list of threads with open upvalues */
 136   Mbuffer buff;  /* temporary buffer for string concatenation */
 137   unsigned int gcfinnum;  /* number of finalizers to call in each GC step */
 138   int gcpause;  /* size of pause between successive GCs */
 139   int gcstepmul;  /* GC 'granularity' */
 140   lua_CFunction panic;  /* to be called in unprotected errors */
 141   struct lua_State *mainthread;
 142   const lua_Number *version;  /* pointer to version number */
 143   TString *memerrmsg;  /* memory-error message */
 144   TString *tmname[TM_N];  /* array with tag-method names */
 145   struct Table *mt[LUA_NUMTAGS];  /* metatables for basic types */
 146   TString *strcache[STRCACHE_SIZE][1];  /* cache for strings in API */
 147 } global_State;
 148
 149
 150 /*
 151 ** 'per thread' state
 152 */
 153 struct lua_State {
 154   CommonHeader;
 155   lu_byte status;
 156   StkId top;  /* first free slot in the stack */
 157   global_State *l_G;
 158   CallInfo *ci;  /* call info for current function */
 159   const Instruction *oldpc;  /* last pc traced */
 160   StkId stack_last;  /* last free slot in the stack */
 161   StkId stack;  /* stack base */
 162   UpVal *openupval;  /* list of open upvalues in this stack */
 163   GCObject *gclist;
 164   struct lua_State *twups;  /* list of threads with open upvalues */
 165   struct lua_longjmp *errorJmp;  /* current error recover point */
 166   CallInfo base_ci;  /* CallInfo for first level (C calling Lua) */
 167   lua_Hook hook;
 168   ptrdiff_t errfunc;  /* current error handling function (stack index) */
 169   int stacksize;
 170   int basehookcount;
 171   int hookcount;
 172   unsigned short nny;  /* number of non-yieldable calls in stack */
 173   unsigned short nCcalls;  /* number of nested C calls */
 174   lu_byte hookmask;
 175   lu_byte allowhook;
 176 };
 177
 178
 179 #define G(L)    (L->l_G)
 180
 181
 182 /*
 183 ** Union of all collectable objects (only for conversions)
 184 */
 185 union GCUnion {
 186   GCObject gc;  /* common header */
 187   struct TString ts;
 188   struct Udata u;
 189   union Closure cl;
 190   struct Table h;
 191   struct Proto p;
 192   struct lua_State th;  /* thread */
 193 };
 194
 195
 196 #define cast_u(o)       cast(union GCUnion *, (o))
 197
 198 /* macros to convert a GCObject into a specific value */
 199 #define gco2ts(o)  \
 200         check_exp(novariant((o)->tt) == LUA_TSTRING, &((cast_u(o))->ts))
 201 #define gco2u(o)  check_exp((o)->tt == LUA_TUSERDATA, &((cast_u(o))->u))
 202 #define gco2lcl(o)  check_exp((o)->tt == LUA_TLCL, &((cast_u(o))->cl.l))
 203 #define gco2ccl(o)  check_exp((o)->tt == LUA_TCCL, &((cast_u(o))->cl.c))
 204 #define gco2cl(o)  \
 205         check_exp(novariant((o)->tt) == LUA_TFUNCTION, &((cast_u(o))->cl))
 206 #define gco2t(o)  check_exp((o)->tt == LUA_TTABLE, &((cast_u(o))->h))
 207 #define gco2p(o)  check_exp((o)->tt == LUA_TPROTO, &((cast_u(o))->p))
 208 #define gco2th(o)  check_exp((o)->tt == LUA_TTHREAD, &((cast_u(o))->th))
 209
 210
 211 /* macro to convert a Lua object into a GCObject */
 212 #define obj2gco(v) \
 213         check_exp(novariant((v)->tt) < LUA_TDEADKEY, (&(cast_u(v)->gc)))
 214
 215
 216 /* actual number of total bytes allocated */
 217 #define gettotalbytes(g)        ((g)->totalbytes + (g)->GCdebt)
 218
 219 LUAI_FUNC void luaE_setdebt (global_State *g, l_mem debt);
 220 LUAI_FUNC void luaE_freethread (lua_State *L, lua_State *L1);
 221 LUAI_FUNC CallInfo *luaE_extendCI (lua_State *L);
 222 LUAI_FUNC void luaE_freeCI (lua_State *L);
 223 LUAI_FUNC void luaE_shrinkCI (lua_State *L);
 224
 225
 226 #endif
 227