/* ** $Id: lstate.h $ ** Global State ** See Copyright Notice in lua.h */ #ifndef lstate_h #define lstate_h #include "lua.h" #include "lobject.h" #include "ltm.h" #include "lzio.h" /* ** Some notes about garbage-collected objects: All objects in Lua must ** be kept somehow accessible until being freed, so all objects always ** belong to one (and only one) of these lists, using field 'next' of ** the 'CommonHeader' for the link: ** ** 'allgc': all objects not marked for finalization; ** 'finobj': all objects marked for finalization; ** 'tobefnz': all objects ready to be finalized; ** 'fixedgc': all objects that are not to be collected (currently ** only small strings, such as reserved words). ** ** For the generational collector, some of these lists have marks for ** generations. Each mark points to the first element in the list for ** that particular generation; that generation goes until the next mark. ** ** 'allgc' -> 'survival': new objects; ** 'survival' -> 'old': objects that survived one collection; ** 'old1' -> 'reallyold': objects that became old in last collection; ** 'reallyold' -> NULL: objects old for more than one cycle. ** ** 'finobj' -> 'finobjsur': new objects marked for finalization; ** 'finobjsur' -> 'finobjold1': survived """"; ** 'finobjold1' -> 'finobjrold': just old """"; ** 'finobjrold' -> NULL: really old """". ** ** All lists can contain elements older than their main ages, due ** to 'luaC_checkfinalizer' and 'udata2finalize', which move ** objects between the normal lists and the "marked for finalization" ** lists. Moreover, barriers can age young objects in young lists as ** OLD0, which then become OLD1. However, a list never contains ** elements younger than their main ages. ** ** The generational collector also uses a pointer 'firstold1', which ** points to the first OLD1 object in the list. It is used to optimize ** 'markold'. (Potentially OLD1 objects can be anywhere between 'allgc' ** and 'reallyold', but often the list has no OLD1 objects or they are ** after 'old1'.) Note the difference between it and 'old1': ** 'firstold1': no OLD1 objects before this point; there can be all ** ages after it. ** 'old1': no objects younger than OLD1 after this point. */ /* ** Moreover, there is another set of lists that control gray objects. ** These lists are linked by fields 'gclist'. (All objects that ** can become gray have such a field. The field is not the same ** in all objects, but it always has this name.) Any gray object ** must belong to one of these lists, and all objects in these lists ** must be gray (with two exceptions explained below): ** ** 'gray': regular gray objects, still waiting to be visited. ** 'grayagain': objects that must be revisited at the atomic phase. ** That includes ** - black objects got in a write barrier; ** - all kinds of weak tables during propagation phase; ** - all threads. ** 'weak': tables with weak values to be cleared; ** 'ephemeron': ephemeron tables with white->white entries; ** 'allweak': tables with weak keys and/or weak values to be cleared. ** ** The exceptions to that "gray rule" are: ** - TOUCHED2 objects in generational mode stay in a gray list (because ** they must be visited again at the end of the cycle), but they are ** marked black because assignments to them must activate barriers (to ** move them back to TOUCHED1). ** - Open upvales are kept gray to avoid barriers, but they stay out ** of gray lists. (They don't even have a 'gclist' field.) */ /* ** About 'nCcalls': each thread in Lua (a lua_State) keeps a count of ** how many "C calls" it still can do in the C stack, to avoid C-stack ** overflow. This count is very rough approximation; it considers only ** recursive functions inside the interpreter, as non-recursive calls ** can be considered using a fixed (although unknown) amount of stack ** space. ** ** The count has two parts: the lower part is the count itself; the ** higher part counts the number of non-yieldable calls in the stack. ** (They are together so that we can change both with one instruction.) ** ** Because calls to external C functions can use an unknown amount ** of space (e.g., functions using an auxiliary buffer), calls ** to these functions add more than one to the count (see CSTACKCF). ** ** The proper count excludes the number of CallInfo structures allocated ** by Lua, as a kind of "potential" calls. So, when Lua calls a function ** (and "consumes" one CallInfo), it needs neither to decrement nor to ** check 'nCcalls', as its use of C stack is already accounted for. */ /* number of "C stack slots" used by an external C function */ #define CSTACKCF 10 /* ** The C-stack size is sliced in the following zones: ** - larger than CSTACKERR: normal stack; ** - [CSTACKMARK, CSTACKERR]: buffer zone to signal a stack overflow; ** - [CSTACKCF, CSTACKERRMARK]: error-handling zone; ** - below CSTACKERRMARK: buffer zone to signal overflow during overflow; ** (Because the counter can be decremented CSTACKCF at once, we need ** the so called "buffer zones", with at least that size, to properly ** detect a change from one zone to the next.) */ #define CSTACKERR (8 * CSTACKCF) #define CSTACKMARK (CSTACKERR - (CSTACKCF + 2)) #define CSTACKERRMARK (CSTACKCF + 2) /* initial limit for the C-stack of threads */ #define CSTACKTHREAD (2 * CSTACKERR) /* true if this thread does not have non-yieldable calls in the stack */ #define yieldable(L) (((L)->nCcalls & 0xffff0000) == 0) /* real number of C calls */ #define getCcalls(L) ((L)->nCcalls & 0xffff) /* Increment the number of non-yieldable calls */ #define incnny(L) ((L)->nCcalls += 0x10000) /* Decrement the number of non-yieldable calls */ #define decnny(L) ((L)->nCcalls -= 0x10000) /* Increment the number of non-yieldable calls and decrement nCcalls */ #define incXCcalls(L) ((L)->nCcalls += 0x10000 - CSTACKCF) /* Decrement the number of non-yieldable calls and increment nCcalls */ #define decXCcalls(L) ((L)->nCcalls -= 0x10000 - CSTACKCF) struct lua_longjmp; /* defined in ldo.c */ /* ** Atomic type (relative to signals) to better ensure that 'lua_sethook' ** is thread safe */ #if !defined(l_signalT) #include #define l_signalT sig_atomic_t #endif /* extra stack space to handle TM calls and some other extras */ #define EXTRA_STACK 5 #define BASIC_STACK_SIZE (2*LUA_MINSTACK) /* kinds of Garbage Collection */ #define KGC_INC 0 /* incremental gc */ #define KGC_GEN 1 /* generational gc */ typedef struct stringtable { TString **hash; int nuse; /* number of elements */ int size; } stringtable; /* ** Information about a call. */ typedef struct CallInfo { StkId func; /* function index in the stack */ StkId top; /* top for this function */ struct CallInfo *previous, *next; /* dynamic call link */ union { struct { /* only for Lua functions */ const Instruction *savedpc; volatile l_signalT trap; int nextraargs; /* # of extra arguments in vararg functions */ } l; struct { /* only for C functions */ lua_KFunction k; /* continuation in case of yields */ ptrdiff_t old_errfunc; lua_KContext ctx; /* context info. in case of yields */ } c; } u; union { int funcidx; /* called-function index */ int nyield; /* number of values yielded */ struct { /* info about transferred values (for call/return hooks) */ unsigned short ftransfer; /* offset of first value transferred */ unsigned short ntransfer; /* number of values transferred */ } transferinfo; } u2; short nresults; /* expected number of results from this function */ unsigned short callstatus; } CallInfo; /* ** Bits in CallInfo status */ #define CIST_OAH (1<<0) /* original value of 'allowhook' */ #define CIST_C (1<<1) /* call is running a C function */ #define CIST_HOOKED (1<<2) /* call is running a debug hook */ #define CIST_YPCALL (1<<3) /* call is a yieldable protected call */ #define CIST_TAIL (1<<4) /* call was tail called */ #define CIST_HOOKYIELD (1<<5) /* last hook called yielded */ #define CIST_FIN (1<<6) /* call is running a finalizer */ #define CIST_TRAN (1<<7) /* 'ci' has transfer information */ #if defined(LUA_COMPAT_LT_LE) #define CIST_LEQ (1<<8) /* using __lt for __le */ #endif /* active function is a Lua function */ #define isLua(ci) (!((ci)->callstatus & CIST_C)) /* call is running Lua code (not a hook) */ #define isLuacode(ci) (!((ci)->callstatus & (CIST_C | CIST_HOOKED))) /* assume that CIST_OAH has offset 0 and that 'v' is strictly 0/1 */ #define setoah(st,v) ((st) = ((st) & ~CIST_OAH) | (v)) #define getoah(st) ((st) & CIST_OAH) /* ** 'global state', shared by all threads of this state */ typedef struct global_State { lua_Alloc frealloc; /* function to reallocate memory */ void *ud; /* auxiliary data to 'frealloc' */ l_mem totalbytes; /* number of bytes currently allocated - GCdebt */ l_mem GCdebt; /* bytes allocated not yet compensated by the collector */ lu_mem GCestimate; /* an estimate of the non-garbage memory in use */ lu_mem lastatomic; /* see function 'genstep' in file 'lgc.c' */ stringtable strt; /* hash table for strings */ TValue l_registry; TValue nilvalue; /* a nil value */ unsigned int seed; /* randomized seed for hashes */ lu_byte currentwhite; lu_byte gcstate; /* state of garbage collector */ lu_byte gckind; /* kind of GC running */ lu_byte genminormul; /* control for minor generational collections */ lu_byte genmajormul; /* control for major generational collections */ lu_byte gcrunning; /* true if GC is running */ lu_byte gcemergency; /* true if this is an emergency collection */ lu_byte gcpause; /* size of pause between successive GCs */ lu_byte gcstepmul; /* GC "speed" */ lu_byte gcstepsize; /* (log2 of) GC granularity */ GCObject *allgc; /* list of all collectable objects */ GCObject **sweepgc; /* current position of sweep in list */ GCObject *finobj; /* list of collectable objects with finalizers */ GCObject *gray; /* list of gray objects */ GCObject *grayagain; /* list of objects to be traversed atomically */ GCObject *weak; /* list of tables with weak values */ GCObject *ephemeron; /* list of ephemeron tables (weak keys) */ GCObject *allweak; /* list of all-weak tables */ GCObject *tobefnz; /* list of userdata to be GC */ GCObject *fixedgc; /* list of objects not to be collected */ /* fields for generational collector */ GCObject *survival; /* start of objects that survived one GC cycle */ GCObject *old1; /* start of old1 objects */ GCObject *reallyold; /* objects more than one cycle old ("really old") */ GCObject *firstold1; /* first OLD1 object in the list (if any) */ GCObject *finobjsur; /* list of survival objects with finalizers */ GCObject *finobjold1; /* list of old1 objects with finalizers */ GCObject *finobjrold; /* list of really old objects with finalizers */ struct lua_State *twups; /* list of threads with open upvalues */ lua_CFunction panic; /* to be called in unprotected errors */ struct lua_State *mainthread; TString *memerrmsg; /* message for memory-allocation errors */ TString *tmname[TM_N]; /* array with tag-method names */ struct Table *mt[LUA_NUMTAGS]; /* metatables for basic types */ TString *strcache[STRCACHE_N][STRCACHE_M]; /* cache for strings in API */ lua_WarnFunction warnf; /* warning function */ void *ud_warn; /* auxiliary data to 'warnf' */ unsigned int Cstacklimit; /* current limit for the C stack */ } global_State; /* ** 'per thread' state */ struct lua_State { CommonHeader; lu_byte status; lu_byte allowhook; unsigned short nci; /* number of items in 'ci' list */ StkId top; /* first free slot in the stack */ global_State *l_G; CallInfo *ci; /* call info for current function */ StkId stack_last; /* last free slot in the stack */ StkId stack; /* stack base */ UpVal *openupval; /* list of open upvalues in this stack */ GCObject *gclist; struct lua_State *twups; /* list of threads with open upvalues */ struct lua_longjmp *errorJmp; /* current error recover point */ CallInfo base_ci; /* CallInfo for first level (C calling Lua) */ volatile lua_Hook hook; ptrdiff_t errfunc; /* current error handling function (stack index) */ l_uint32 nCcalls; /* number of allowed nested C calls - 'nci' */ int oldpc; /* last pc traced */ int stacksize; int basehookcount; int hookcount; volatile l_signalT hookmask; }; #define G(L) (L->l_G) /* ** Union of all collectable objects (only for conversions) ** ISO C99, 6.5.2.3 p.5: ** "if a union contains several structures that share a common initial ** sequence [...], and if the union object currently contains one ** of these structures, it is permitted to inspect the common initial ** part of any of them anywhere that a declaration of the complete type ** of the union is visible." */ union GCUnion { GCObject gc; /* common header */ struct TString ts; struct Udata u; union Closure cl; struct Table h; struct Proto p; struct lua_State th; /* thread */ struct UpVal upv; }; /* ** ISO C99, 6.7.2.1 p.14: ** "A pointer to a union object, suitably converted, points to each of ** its members [...], and vice versa." */ #define cast_u(o) cast(union GCUnion *, (o)) /* macros to convert a GCObject into a specific value */ #define gco2ts(o) \ check_exp(novariant((o)->tt) == LUA_TSTRING, &((cast_u(o))->ts)) #define gco2u(o) check_exp((o)->tt == LUA_VUSERDATA, &((cast_u(o))->u)) #define gco2lcl(o) check_exp((o)->tt == LUA_VLCL, &((cast_u(o))->cl.l)) #define gco2ccl(o) check_exp((o)->tt == LUA_VCCL, &((cast_u(o))->cl.c)) #define gco2cl(o) \ check_exp(novariant((o)->tt) == LUA_TFUNCTION, &((cast_u(o))->cl)) #define gco2t(o) check_exp((o)->tt == LUA_VTABLE, &((cast_u(o))->h)) #define gco2p(o) check_exp((o)->tt == LUA_VPROTO, &((cast_u(o))->p)) #define gco2th(o) check_exp((o)->tt == LUA_VTHREAD, &((cast_u(o))->th)) #define gco2upv(o) check_exp((o)->tt == LUA_VUPVAL, &((cast_u(o))->upv)) /* ** macro to convert a Lua object into a GCObject ** (The access to 'tt' tries to ensure that 'v' is actually a Lua object.) */ #define obj2gco(v) check_exp((v)->tt >= LUA_TSTRING, &(cast_u(v)->gc)) /* actual number of total bytes allocated */ #define gettotalbytes(g) cast(lu_mem, (g)->totalbytes + (g)->GCdebt) LUAI_FUNC void luaE_setdebt (global_State *g, l_mem debt); LUAI_FUNC void luaE_freethread (lua_State *L, lua_State *L1); LUAI_FUNC CallInfo *luaE_extendCI (lua_State *L); LUAI_FUNC void luaE_freeCI (lua_State *L); LUAI_FUNC void luaE_shrinkCI (lua_State *L); LUAI_FUNC void luaE_enterCcall (lua_State *L); LUAI_FUNC void luaE_warning (lua_State *L, const char *msg, int tocont); LUAI_FUNC void luaE_warnerror (lua_State *L, const char *where); #define luaE_exitCcall(L) ((L)->nCcalls++) #endif