2 ** $Id: lstate.h,v 2.133.1.1 2017/04/19 17:39:34 roberto Exp $
4 ** See Copyright Notice in lua.h
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:
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).
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
37 ** 'gray': regular gray objects, still waiting to be visited.
38 ** 'grayagain': objects that must be revisited at the atomic phase.
40 ** - black objects got in a write barrier;
41 ** - all kinds of weak tables during propagation phase;
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.
51 struct lua_longjmp; /* defined in ldo.c */
55 ** Atomic type (relative to signals) to better ensure that 'lua_sethook'
58 #if !defined(l_signalT)
60 #define l_signalT sig_atomic_t
64 /* extra stack space to handle TM calls and some other extras */
68 #define BASIC_STACK_SIZE (2*LUA_MINSTACK)
71 /* kinds of Garbage Collection */
73 #define KGC_EMERGENCY 1 /* gc was forced by an allocation failure */
76 typedef struct stringtable {
78 int nuse; /* number of elements */
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.
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 */
97 struct { /* only for Lua functions */
98 StkId base; /* base for this function */
99 const Instruction *savedpc;
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 */
108 short nresults; /* expected number of results from this function */
109 unsigned short callstatus;
114 ** Bits in CallInfo status
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
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 */
127 #define isLua(ci) ((ci)->callstatus & CIST_LUA)
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)
135 ** 'global state', shared by all threads of this state
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 */
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 */
176 ** 'per thread' state
180 unsigned short nci; /* number of items in 'ci' list */
182 StkId top; /* first free slot in the stack */
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 */
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) */
198 unsigned short nny; /* number of non-yieldable calls in stack */
199 unsigned short nCcalls; /* number of nested C calls */
205 #define G(L) (L->l_G)
209 ** Union of all collectable objects (only for conversions)
212 GCObject gc; /* common header */
218 struct lua_State th; /* thread */
222 #define cast_u(o) cast(union GCUnion *, (o))
224 /* macros to convert a GCObject into a specific value */
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))
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))
237 /* macro to convert a Lua object into a GCObject */
239 check_exp(novariant((v)->tt) < LUA_TDEADKEY, (&(cast_u(v)->gc)))
242 /* actual number of total bytes allocated */
243 #define gettotalbytes(g) cast(lu_mem, (g)->totalbytes + (g)->GCdebt)
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);