1/*
2** $Id: lstate.h,v 2.133.1.1 2017/04/19 17:39:34 roberto Exp $
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
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:
23**
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).
29**
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
35** must be gray:
36**
37** 'gray': regular gray objects, still waiting to be visited.
38** 'grayagain': objects that must be revisited at the atomic phase.
39** That includes
40** - black objects got in a write barrier;
41** - all kinds of weak tables during propagation phase;
42** - all threads.
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.
47
48*/
49
50
51struct lua_longjmp; /* defined in ldo.c */
52
53
54/*
55** Atomic type (relative to signals) to better ensure that 'lua_sethook'
56** is thread safe
57*/
58#if !defined(l_signalT)
59#include <signal.h>
60#define l_signalT sig_atomic_t
61#endif
62
63
64/* extra stack space to handle TM calls and some other extras */
65#define EXTRA_STACK 5
66
67
68#define BASIC_STACK_SIZE (2*LUA_MINSTACK)
69
70
71/* kinds of Garbage Collection */
72#define KGC_NORMAL 0
73#define KGC_EMERGENCY 1 /* gc was forced by an allocation failure */
74
75
76typedef struct stringtable {
77 TString **hash;
78 int nuse; /* number of elements */
79 int size;
80} stringtable;
81
82
83/*
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.
91*/
92typedef 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 */
96 union {
97 struct { /* only for Lua functions */
98 StkId base; /* base for this function */
99 const Instruction *savedpc;
100 } l;
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 */
105 } c;
106 } u;
107 ptrdiff_t extra;
108 short nresults; /* expected number of results from this function */
109 unsigned short callstatus;
110} CallInfo;
111
112
113/*
114** Bits in CallInfo status
115*/
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
120 of luaV_execute */
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 */
126
127#define isLua(ci) ((ci)->callstatus & CIST_LUA)
128
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)
132
133
134/*
135** 'global state', shared by all threads of this state
136*/
137typedef 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 */
145 TValue l_registry;
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 */
172} global_State;
173
174
175/*
176** 'per thread' state
177*/
178struct lua_State {
179 CommonHeader;
180 unsigned short nci; /* number of items in 'ci' list */
181 lu_byte status;
182 StkId top; /* first free slot in the stack */
183 global_State *l_G;
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 */
189 GCObject *gclist;
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) */
195 int stacksize;
196 int basehookcount;
197 int hookcount;
198 unsigned short nny; /* number of non-yieldable calls in stack */
199 unsigned short nCcalls; /* number of nested C calls */
200 l_signalT hookmask;
201 lu_byte allowhook;
202};
203
204
205#define G(L) (L->l_G)
206
207
208/*
209** Union of all collectable objects (only for conversions)
210*/
211union GCUnion {
212 GCObject gc; /* common header */
213 struct TString ts;
214 struct Udata u;
215 union Closure cl;
216 struct Table h;
217 struct Proto p;
218 struct lua_State th; /* thread */
219};
220
221
222#define cast_u(o) cast(union GCUnion *, (o))
223
224/* macros to convert a GCObject into a specific value */
225#define gco2ts(o) \
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))
230#define gco2cl(o) \
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))
235
236
237/* macro to convert a Lua object into a GCObject */
238#define obj2gco(v) \
239 check_exp(novariant((v)->tt) < LUA_TDEADKEY, (&(cast_u(v)->gc)))
240
241
242/* actual number of total bytes allocated */
243#define gettotalbytes(g) cast(lu_mem, (g)->totalbytes + (g)->GCdebt)
244
245LUAI_FUNC void luaE_setdebt (global_State *g, l_mem debt);
246LUAI_FUNC void luaE_freethread (lua_State *L, lua_State *L1);
247LUAI_FUNC CallInfo *luaE_extendCI (lua_State *L);
248LUAI_FUNC void luaE_freeCI (lua_State *L);
249LUAI_FUNC void luaE_shrinkCI (lua_State *L);
250
251
252#endif
253
254