xref: /freebsd/sys/contrib/openzfs/module/lua/lstate.h (revision 25ecdc7d52770caf1c9b44b5ec11f468f6b636f3)
1 /* BEGIN CSTYLED */
2 /*
3 ** $Id: lstate.h,v 2.82.1.1 2013/04/12 18:48:47 roberto Exp $
4 ** Global State
5 ** See Copyright Notice in lua.h
6 */
7 
8 #ifndef lstate_h
9 #define lstate_h
10 
11 #include <sys/lua/lua.h>
12 
13 #include "lobject.h"
14 #include "ltm.h"
15 #include "lzio.h"
16 
17 
18 /*
19 
20 ** Some notes about garbage-collected objects:  All objects in Lua must
21 ** be kept somehow accessible until being freed.
22 **
23 ** Lua keeps most objects linked in list g->allgc. The link uses field
24 ** 'next' of the CommonHeader.
25 **
26 ** Strings are kept in several lists headed by the array g->strt.hash.
27 **
28 ** Open upvalues are not subject to independent garbage collection. They
29 ** are collected together with their respective threads. Lua keeps a
30 ** double-linked list with all open upvalues (g->uvhead) so that it can
31 ** mark objects referred by them. (They are always gray, so they must
32 ** be remarked in the atomic step. Usually their contents would be marked
33 ** when traversing the respective threads, but the thread may already be
34 ** dead, while the upvalue is still accessible through closures.)
35 **
36 ** Objects with finalizers are kept in the list g->finobj.
37 **
38 ** The list g->tobefnz links all objects being finalized.
39 
40 */
41 
42 
43 struct lua_longjmp;  /* defined in ldo.c */
44 
45 
46 
47 /* extra stack space to handle TM calls and some other extras */
48 #define EXTRA_STACK   5
49 
50 
51 #define BASIC_STACK_SIZE        (2*LUA_MINSTACK)
52 
53 
54 /* kinds of Garbage Collection */
55 #define KGC_NORMAL	0
56 #define KGC_EMERGENCY	1	/* gc was forced by an allocation failure */
57 #define KGC_GEN		2	/* generational collection */
58 
59 
60 typedef struct stringtable {
61   GCObject **hash;
62   lu_int32 nuse;  /* number of elements */
63   int size;
64 } stringtable;
65 
66 
67 /*
68 ** information about a call
69 */
70 typedef struct CallInfo {
71   StkId func;  /* function index in the stack */
72   StkId	top;  /* top for this function */
73   struct CallInfo *previous, *next;  /* dynamic call link */
74   short nresults;  /* expected number of results from this function */
75   lu_byte callstatus;
76   ptrdiff_t extra;
77   union {
78     struct {  /* only for Lua functions */
79       StkId base;  /* base for this function */
80       const Instruction *savedpc;
81     } l;
82     struct {  /* only for C functions */
83       int ctx;  /* context info. in case of yields */
84       lua_CFunction k;  /* continuation in case of yields */
85       ptrdiff_t old_errfunc;
86       lu_byte old_allowhook;
87       lu_byte status;
88     } c;
89   } u;
90 } CallInfo;
91 
92 
93 /*
94 ** Bits in CallInfo status
95 */
96 #define CIST_LUA	(1<<0)	/* call is running a Lua function */
97 #define CIST_HOOKED	(1<<1)	/* call is running a debug hook */
98 #define CIST_REENTRY	(1<<2)	/* call is running on same invocation of
99                                    luaV_execute of previous call */
100 #define CIST_YIELDED	(1<<3)	/* call reentered after suspension */
101 #define CIST_YPCALL	(1<<4)	/* call is a yieldable protected call */
102 #define CIST_STAT	(1<<5)	/* call has an error status (pcall) */
103 #define CIST_TAIL	(1<<6)	/* call was tail called */
104 #define CIST_HOOKYIELD	(1<<7)	/* last hook called yielded */
105 
106 
107 #define isLua(ci)	((ci)->callstatus & CIST_LUA)
108 
109 
110 /*
111 ** `global state', shared by all threads of this state
112 */
113 typedef struct global_State {
114   lua_Alloc frealloc;  /* function to reallocate memory */
115   void *ud;         /* auxiliary data to `frealloc' */
116   lu_mem totalbytes;  /* number of bytes currently allocated - GCdebt */
117   l_mem GCdebt;  /* bytes allocated not yet compensated by the collector */
118   lu_mem GCmemtrav;  /* memory traversed by the GC */
119   lu_mem GCestimate;  /* an estimate of the non-garbage memory in use */
120   stringtable strt;  /* hash table for strings */
121   TValue l_registry;
122   unsigned int seed;  /* randomized seed for hashes */
123   lu_byte currentwhite;
124   lu_byte gcstate;  /* state of garbage collector */
125   lu_byte gckind;  /* kind of GC running */
126   lu_byte gcrunning;  /* true if GC is running */
127   int sweepstrgc;  /* position of sweep in `strt' */
128   GCObject *allgc;  /* list of all collectable objects */
129   GCObject *finobj;  /* list of collectable objects with finalizers */
130   GCObject **sweepgc;  /* current position of sweep in list 'allgc' */
131   GCObject **sweepfin;  /* current position of sweep in list 'finobj' */
132   GCObject *gray;  /* list of gray objects */
133   GCObject *grayagain;  /* list of objects to be traversed atomically */
134   GCObject *weak;  /* list of tables with weak values */
135   GCObject *ephemeron;  /* list of ephemeron tables (weak keys) */
136   GCObject *allweak;  /* list of all-weak tables */
137   GCObject *tobefnz;  /* list of userdata to be GC */
138   UpVal uvhead;  /* head of double-linked list of all open upvalues */
139   Mbuffer buff;  /* temporary buffer for string concatenation */
140   int gcpause;  /* size of pause between successive GCs */
141   int gcmajorinc;  /* pause between major collections (only in gen. mode) */
142   int gcstepmul;  /* GC `granularity' */
143   lua_CFunction panic;  /* to be called in unprotected errors */
144   struct lua_State *mainthread;
145   const lua_Number *version;  /* pointer to version number */
146   TString *memerrmsg;  /* memory-error message */
147   TString *tmname[TM_N];  /* array with tag-method names */
148   struct Table *mt[LUA_NUMTAGS];  /* metatables for basic types */
149 } global_State;
150 
151 
152 /*
153 ** `per thread' state
154 */
155 struct lua_State {
156   CommonHeader;
157   lu_byte status;
158   StkId top;  /* first free slot in the stack */
159   global_State *l_G;
160   CallInfo *ci;  /* call info for current function */
161   const Instruction *oldpc;  /* last pc traced */
162   StkId stack_last;  /* last free slot in the stack */
163   StkId stack;  /* stack base */
164   int stacksize;
165   unsigned short nny;  /* number of non-yieldable calls in stack */
166   unsigned short nCcalls;  /* number of nested C calls */
167   lu_byte hookmask;
168   lu_byte allowhook;
169   lu_byte runerror; /* handling a runtime error */
170   int basehookcount;
171   int hookcount;
172   lua_Hook hook;
173   GCObject *openupval;  /* list of open upvalues in this stack */
174   GCObject *gclist;
175   struct lua_longjmp *errorJmp;  /* current error recover point */
176   ptrdiff_t errfunc;  /* current error handling function (stack index) */
177   CallInfo base_ci;  /* CallInfo for first level (C calling Lua) */
178 };
179 
180 
181 #define G(L)	(L->l_G)
182 
183 
184 /*
185 ** Union of all collectable objects
186 */
187 union GCObject {
188   GCheader gch;  /* common header */
189   union TString ts;
190   union Udata u;
191   union Closure cl;
192   struct Table h;
193   struct Proto p;
194   struct UpVal uv;
195   struct lua_State th;  /* thread */
196 };
197 
198 
199 #define gch(o)		(&(o)->gch)
200 
201 /* macros to convert a GCObject into a specific value */
202 #define rawgco2ts(o)  \
203 	check_exp(novariant((o)->gch.tt) == LUA_TSTRING, &((o)->ts))
204 #define gco2ts(o)	(&rawgco2ts(o)->tsv)
205 #define rawgco2u(o)	check_exp((o)->gch.tt == LUA_TUSERDATA, &((o)->u))
206 #define gco2u(o)	(&rawgco2u(o)->uv)
207 #define gco2lcl(o)	check_exp((o)->gch.tt == LUA_TLCL, &((o)->cl.l))
208 #define gco2ccl(o)	check_exp((o)->gch.tt == LUA_TCCL, &((o)->cl.c))
209 #define gco2cl(o)  \
210 	check_exp(novariant((o)->gch.tt) == LUA_TFUNCTION, &((o)->cl))
211 #define gco2t(o)	check_exp((o)->gch.tt == LUA_TTABLE, &((o)->h))
212 #define gco2p(o)	check_exp((o)->gch.tt == LUA_TPROTO, &((o)->p))
213 #define gco2uv(o)	check_exp((o)->gch.tt == LUA_TUPVAL, &((o)->uv))
214 #define gco2th(o)	check_exp((o)->gch.tt == LUA_TTHREAD, &((o)->th))
215 
216 /* macro to convert any Lua object into a GCObject */
217 #define obj2gco(v)	(cast(GCObject *, (v)))
218 
219 
220 /* actual number of total bytes allocated */
221 #define gettotalbytes(g)	((g)->totalbytes + (g)->GCdebt)
222 
223 LUAI_FUNC void luaE_setdebt (global_State *g, l_mem debt);
224 LUAI_FUNC void luaE_freethread (lua_State *L, lua_State *L1);
225 LUAI_FUNC CallInfo *luaE_extendCI (lua_State *L);
226 LUAI_FUNC void luaE_freeCI (lua_State *L);
227 
228 
229 #endif
230 /* END CSTYLED */
231