1/*
2** $Id: lstate.h $
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** Some notes about garbage-collected objects: All objects in Lua must
19** be kept somehow accessible until being freed, so all objects always
20** belong to one (and only one) of these lists, using field 'next' of
21** the 'CommonHeader' for the link:
22**
23** 'allgc': all objects not marked for finalization;
24** 'finobj': all objects marked for finalization;
25** 'tobefnz': all objects ready to be finalized;
26** 'fixedgc': all objects that are not to be collected (currently
27** only small strings, such as reserved words).
28**
29** For the generational collector, some of these lists have marks for
30** generations. Each mark points to the first element in the list for
31** that particular generation; that generation goes until the next mark.
32**
33** 'allgc' -> 'survival': new objects;
34** 'survival' -> 'old': objects that survived one collection;
35** 'old1' -> 'reallyold': objects that became old in last collection;
36** 'reallyold' -> NULL: objects old for more than one cycle.
37**
38** 'finobj' -> 'finobjsur': new objects marked for finalization;
39** 'finobjsur' -> 'finobjold1': survived """";
40** 'finobjold1' -> 'finobjrold': just old """";
41** 'finobjrold' -> NULL: really old """".
42**
43** All lists can contain elements older than their main ages, due
44** to 'luaC_checkfinalizer' and 'udata2finalize', which move
45** objects between the normal lists and the "marked for finalization"
46** lists. Moreover, barriers can age young objects in young lists as
47** OLD0, which then become OLD1. However, a list never contains
48** elements younger than their main ages.
49**
50** The generational collector also uses a pointer 'firstold1', which
51** points to the first OLD1 object in the list. It is used to optimize
52** 'markold'. (Potentially OLD1 objects can be anywhere between 'allgc'
53** and 'reallyold', but often the list has no OLD1 objects or they are
54** after 'old1'.) Note the difference between it and 'old1':
55** 'firstold1': no OLD1 objects before this point; there can be all
56** ages after it.
57** 'old1': no objects younger than OLD1 after this point.
58*/
59
60/*
61** Moreover, there is another set of lists that control gray objects.
62** These lists are linked by fields 'gclist'. (All objects that
63** can become gray have such a field. The field is not the same
64** in all objects, but it always has this name.) Any gray object
65** must belong to one of these lists, and all objects in these lists
66** must be gray (with two exceptions explained below):
67**
68** 'gray': regular gray objects, still waiting to be visited.
69** 'grayagain': objects that must be revisited at the atomic phase.
70** That includes
71** - black objects got in a write barrier;
72** - all kinds of weak tables during propagation phase;
73** - all threads.
74** 'weak': tables with weak values to be cleared;
75** 'ephemeron': ephemeron tables with white->white entries;
76** 'allweak': tables with weak keys and/or weak values to be cleared.
77**
78** The exceptions to that "gray rule" are:
79** - TOUCHED2 objects in generational mode stay in a gray list (because
80** they must be visited again at the end of the cycle), but they are
81** marked black because assignments to them must activate barriers (to
82** move them back to TOUCHED1).
83** - Open upvales are kept gray to avoid barriers, but they stay out
84** of gray lists. (They don't even have a 'gclist' field.)
85*/
86
87
88
89/*
90** About 'nCcalls': This count has two parts: the lower 16 bits counts
91** the number of recursive invocations in the C stack; the higher
92** 16 bits counts the number of non-yieldable calls in the stack.
93** (They are together so that we can change and save both with one
94** instruction.)
95*/
96
97
98/* true if this thread does not have non-yieldable calls in the stack */
99#define yieldable(L) (((L)->nCcalls & 0xffff0000) == 0)
100
101/* real number of C calls */
102#define getCcalls(L) ((L)->nCcalls & 0xffff)
103
104
105/* Increment the number of non-yieldable calls */
106#define incnny(L) ((L)->nCcalls += 0x10000)
107
108/* Decrement the number of non-yieldable calls */
109#define decnny(L) ((L)->nCcalls -= 0x10000)
110
111/* Non-yieldable call increment */
112#define nyci (0x10000 | 1)
113
114
115
116
117struct lua_longjmp; /* defined in ldo.c */
118
119
120/*
121** Atomic type (relative to signals) to better ensure that 'lua_sethook'
122** is thread safe
123*/
124#if !defined(l_signalT)
125#include <signal.h>
126#define l_signalT sig_atomic_t
127#endif
128
129
130/*
131** Extra stack space to handle TM calls and some other extras. This
132** space is not included in 'stack_last'. It is used only to avoid stack
133** checks, either because the element will be promptly popped or because
134** there will be a stack check soon after the push. Function frames
135** never use this extra space, so it does not need to be kept clean.
136*/
137#define EXTRA_STACK 5
138
139
140#define BASIC_STACK_SIZE (2*LUA_MINSTACK)
141
142#define stacksize(th) cast_int((th)->stack_last - (th)->stack)
143
144
145/* kinds of Garbage Collection */
146#define KGC_INC 0 /* incremental gc */
147#define KGC_GEN 1 /* generational gc */
148
149
150typedef struct stringtable {
151 TString **hash;
152 int nuse; /* number of elements */
153 int size;
154} stringtable;
155
156
157/*
158** Information about a call.
159** About union 'u':
160** - field 'l' is used only for Lua functions;
161** - field 'c' is used only for C functions.
162** About union 'u2':
163** - field 'funcidx' is used only by C functions while doing a
164** protected call;
165** - field 'nyield' is used only while a function is "doing" an
166** yield (from the yield until the next resume);
167** - field 'nres' is used only while closing tbc variables when
168** returning from a C function;
169** - field 'transferinfo' is used only during call/returnhooks,
170** before the function starts or after it ends.
171*/
172typedef struct CallInfo {
173 StkId func; /* function index in the stack */
174 StkId top; /* top for this function */
175 struct CallInfo *previous, *next; /* dynamic call link */
176 union {
177 struct { /* only for Lua functions */
178 const Instruction *savedpc;
179 volatile l_signalT trap;
180 int nextraargs; /* # of extra arguments in vararg functions */
181 } l;
182 struct { /* only for C functions */
183 lua_KFunction k; /* continuation in case of yields */
184 ptrdiff_t old_errfunc;
185 lua_KContext ctx; /* context info. in case of yields */
186 } c;
187 } u;
188 union {
189 int funcidx; /* called-function index */
190 int nyield; /* number of values yielded */
191 int nres; /* number of values returned */
192 struct { /* info about transferred values (for call/return hooks) */
193 unsigned short ftransfer; /* offset of first value transferred */
194 unsigned short ntransfer; /* number of values transferred */
195 } transferinfo;
196 } u2;
197 short nresults; /* expected number of results from this function */
198 unsigned short callstatus;
199} CallInfo;
200
201
202/*
203** Bits in CallInfo status
204*/
205#define CIST_OAH (1<<0) /* original value of 'allowhook' */
206#define CIST_C (1<<1) /* call is running a C function */
207#define CIST_FRESH (1<<2) /* call is on a fresh "luaV_execute" frame */
208#define CIST_HOOKED (1<<3) /* call is running a debug hook */
209#define CIST_YPCALL (1<<4) /* doing a yieldable protected call */
210#define CIST_TAIL (1<<5) /* call was tail called */
211#define CIST_HOOKYIELD (1<<6) /* last hook called yielded */
212#define CIST_FIN (1<<7) /* call is running a finalizer */
213#define CIST_TRAN (1<<8) /* 'ci' has transfer information */
214#define CIST_CLSRET (1<<9) /* function is closing tbc variables */
215/* Bits 10-12 are used for CIST_RECST (see below) */
216#define CIST_RECST 10
217#if defined(LUA_COMPAT_LT_LE)
218#define CIST_LEQ (1<<13) /* using __lt for __le */
219#endif
220
221
222/*
223** Field CIST_RECST stores the "recover status", used to keep the error
224** status while closing to-be-closed variables in coroutines, so that
225** Lua can correctly resume after an yield from a __close method called
226** because of an error. (Three bits are enough for error status.)
227*/
228#define getcistrecst(ci) (((ci)->callstatus >> CIST_RECST) & 7)
229#define setcistrecst(ci,st) \
230 check_exp(((st) & 7) == (st), /* status must fit in three bits */ \
231 ((ci)->callstatus = ((ci)->callstatus & ~(7 << CIST_RECST)) \
232 | ((st) << CIST_RECST)))
233
234
235/* active function is a Lua function */
236#define isLua(ci) (!((ci)->callstatus & CIST_C))
237
238/* call is running Lua code (not a hook) */
239#define isLuacode(ci) (!((ci)->callstatus & (CIST_C | CIST_HOOKED)))
240
241/* assume that CIST_OAH has offset 0 and that 'v' is strictly 0/1 */
242#define setoah(st,v) ((st) = ((st) & ~CIST_OAH) | (v))
243#define getoah(st) ((st) & CIST_OAH)
244
245
246/*
247** 'global state', shared by all threads of this state
248*/
249typedef struct global_State {
250 lua_Alloc frealloc; /* function to reallocate memory */
251 void *ud; /* auxiliary data to 'frealloc' */
252 l_mem totalbytes; /* number of bytes currently allocated - GCdebt */
253 l_mem GCdebt; /* bytes allocated not yet compensated by the collector */
254 lu_mem GCestimate; /* an estimate of the non-garbage memory in use */
255 lu_mem lastatomic; /* see function 'genstep' in file 'lgc.c' */
256 stringtable strt; /* hash table for strings */
257 TValue l_registry;
258 TValue nilvalue; /* a nil value */
259 unsigned int seed; /* randomized seed for hashes */
260 lu_byte currentwhite;
261 lu_byte gcstate; /* state of garbage collector */
262 lu_byte gckind; /* kind of GC running */
263 lu_byte gcstopem; /* stops emergency collections */
264 lu_byte genminormul; /* control for minor generational collections */
265 lu_byte genmajormul; /* control for major generational collections */
266 lu_byte gcrunning; /* true if GC is running */
267 lu_byte gcemergency; /* true if this is an emergency collection */
268 lu_byte gcpause; /* size of pause between successive GCs */
269 lu_byte gcstepmul; /* GC "speed" */
270 lu_byte gcstepsize; /* (log2 of) GC granularity */
271 GCObject *allgc; /* list of all collectable objects */
272 GCObject **sweepgc; /* current position of sweep in list */
273 GCObject *finobj; /* list of collectable objects with finalizers */
274 GCObject *gray; /* list of gray objects */
275 GCObject *grayagain; /* list of objects to be traversed atomically */
276 GCObject *weak; /* list of tables with weak values */
277 GCObject *ephemeron; /* list of ephemeron tables (weak keys) */
278 GCObject *allweak; /* list of all-weak tables */
279 GCObject *tobefnz; /* list of userdata to be GC */
280 GCObject *fixedgc; /* list of objects not to be collected */
281 /* fields for generational collector */
282 GCObject *survival; /* start of objects that survived one GC cycle */
283 GCObject *old1; /* start of old1 objects */
284 GCObject *reallyold; /* objects more than one cycle old ("really old") */
285 GCObject *firstold1; /* first OLD1 object in the list (if any) */
286 GCObject *finobjsur; /* list of survival objects with finalizers */
287 GCObject *finobjold1; /* list of old1 objects with finalizers */
288 GCObject *finobjrold; /* list of really old objects with finalizers */
289 struct lua_State *twups; /* list of threads with open upvalues */
290 lua_CFunction panic; /* to be called in unprotected errors */
291 struct lua_State *mainthread;
292 TString *memerrmsg; /* message for memory-allocation errors */
293 TString *tmname[TM_N]; /* array with tag-method names */
294 struct Table *mt[LUA_NUMTAGS]; /* metatables for basic types */
295 TString *strcache[STRCACHE_N][STRCACHE_M]; /* cache for strings in API */
296 lua_WarnFunction warnf; /* warning function */
297 void *ud_warn; /* auxiliary data to 'warnf' */
298} global_State;
299
300
301/*
302** 'per thread' state
303*/
304struct lua_State {
305 CommonHeader;
306 lu_byte status;
307 lu_byte allowhook;
308 unsigned short nci; /* number of items in 'ci' list */
309 StkId top; /* first free slot in the stack */
310 global_State *l_G;
311 CallInfo *ci; /* call info for current function */
312 StkId stack_last; /* end of stack (last element + 1) */
313 StkId stack; /* stack base */
314 UpVal *openupval; /* list of open upvalues in this stack */
315 StkId tbclist; /* list of to-be-closed variables */
316 GCObject *gclist;
317 struct lua_State *twups; /* list of threads with open upvalues */
318 struct lua_longjmp *errorJmp; /* current error recover point */
319 CallInfo base_ci; /* CallInfo for first level (C calling Lua) */
320 volatile lua_Hook hook;
321 ptrdiff_t errfunc; /* current error handling function (stack index) */
322 l_uint32 nCcalls; /* number of nested (non-yieldable | C) calls */
323 int oldpc; /* last pc traced */
324 int basehookcount;
325 int hookcount;
326 volatile l_signalT hookmask;
327};
328
329
330#define G(L) (L->l_G)
331
332/*
333** 'g->nilvalue' being a nil value flags that the state was completely
334** build.
335*/
336#define completestate(g) ttisnil(&g->nilvalue)
337
338
339/*
340** Union of all collectable objects (only for conversions)
341** ISO C99, 6.5.2.3 p.5:
342** "if a union contains several structures that share a common initial
343** sequence [...], and if the union object currently contains one
344** of these structures, it is permitted to inspect the common initial
345** part of any of them anywhere that a declaration of the complete type
346** of the union is visible."
347*/
348union GCUnion {
349 GCObject gc; /* common header */
350 struct TString ts;
351 struct Udata u;
352 union Closure cl;
353 struct Table h;
354 struct Proto p;
355 struct lua_State th; /* thread */
356 struct UpVal upv;
357};
358
359
360/*
361** ISO C99, 6.7.2.1 p.14:
362** "A pointer to a union object, suitably converted, points to each of
363** its members [...], and vice versa."
364*/
365#define cast_u(o) cast(union GCUnion *, (o))
366
367/* macros to convert a GCObject into a specific value */
368#define gco2ts(o) \
369 check_exp(novariant((o)->tt) == LUA_TSTRING, &((cast_u(o))->ts))
370#define gco2u(o) check_exp((o)->tt == LUA_VUSERDATA, &((cast_u(o))->u))
371#define gco2lcl(o) check_exp((o)->tt == LUA_VLCL, &((cast_u(o))->cl.l))
372#define gco2ccl(o) check_exp((o)->tt == LUA_VCCL, &((cast_u(o))->cl.c))
373#define gco2cl(o) \
374 check_exp(novariant((o)->tt) == LUA_TFUNCTION, &((cast_u(o))->cl))
375#define gco2t(o) check_exp((o)->tt == LUA_VTABLE, &((cast_u(o))->h))
376#define gco2p(o) check_exp((o)->tt == LUA_VPROTO, &((cast_u(o))->p))
377#define gco2th(o) check_exp((o)->tt == LUA_VTHREAD, &((cast_u(o))->th))
378#define gco2upv(o) check_exp((o)->tt == LUA_VUPVAL, &((cast_u(o))->upv))
379
380
381/*
382** macro to convert a Lua object into a GCObject
383** (The access to 'tt' tries to ensure that 'v' is actually a Lua object.)
384*/
385#define obj2gco(v) check_exp((v)->tt >= LUA_TSTRING, &(cast_u(v)->gc))
386
387
388/* actual number of total bytes allocated */
389#define gettotalbytes(g) cast(lu_mem, (g)->totalbytes + (g)->GCdebt)
390
391LUAI_FUNC void luaE_setdebt (global_State *g, l_mem debt);
392LUAI_FUNC void luaE_freethread (lua_State *L, lua_State *L1);
393LUAI_FUNC CallInfo *luaE_extendCI (lua_State *L);
394LUAI_FUNC void luaE_freeCI (lua_State *L);
395LUAI_FUNC void luaE_shrinkCI (lua_State *L);
396LUAI_FUNC void luaE_checkcstack (lua_State *L);
397LUAI_FUNC void luaE_incCstack (lua_State *L);
398LUAI_FUNC void luaE_warning (lua_State *L, const char *msg, int tocont);
399LUAI_FUNC void luaE_warnerror (lua_State *L, const char *where);
400LUAI_FUNC int luaE_resetthread (lua_State *L, int status);
401
402
403#endif
404
405