2 ** $Id: lstate.h,v 2.133 2016/12/22 13:08:50 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).
33 struct lua_longjmp; /* defined in ldo.c */
37 ** Atomic type (relative to signals) to better ensure that 'lua_sethook'
40 #if !defined(l_signalT)
42 #define l_signalT sig_atomic_t
46 /* extra stack space to handle TM calls and some other extras */
50 #define BASIC_STACK_SIZE (2*LUA_MINSTACK)
53 /* kinds of Garbage Collection */
55 #define KGC_EMERGENCY 1 /* gc was forced by an allocation failure */
58 typedef struct stringtable {
60 int nuse; /* number of elements */
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.
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 */
79 struct { /* only for Lua functions */
80 StkId base; /* base for this function */
81 const Instruction *savedpc;
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 */
90 short nresults; /* expected number of results from this function */
91 unsigned short callstatus;
96 ** Bits in CallInfo status
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
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 */
109 #define isLua(ci) ((ci)->callstatus & CIST_LUA)
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)
117 ** 'global state', shared by all threads of this state
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 */
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 */
158 ** 'per thread' state
162 unsigned short nci; /* number of items in 'ci' list */
164 StkId top; /* first free slot in the stack */
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 */
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) */
180 unsigned short nny; /* number of non-yieldable calls in stack */
181 unsigned short nCcalls; /* number of nested C calls */
187 #define G(L) (L->l_G)
191 ** Union of all collectable objects (only for conversions)
194 GCObject gc; /* common header */
200 struct lua_State th; /* thread */
204 #define cast_u(o) cast(union GCUnion *, (o))
206 /* macros to convert a GCObject into a specific value */
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))
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))
219 /* macro to convert a Lua object into a GCObject */
221 check_exp(novariant((v)->tt) < LUA_TDEADKEY, (&(cast_u(v)->gc)))
224 /* actual number of total bytes allocated */
225 #define gettotalbytes(g) cast(lu_mem, (g)->totalbytes + (g)->GCdebt)
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);