1 /* $NetBSD: lfunc.c,v 1.11 2023/06/08 21:12:08 nikita Exp $ */
2
3 /*
4 ** Id: lfunc.c
5 ** Auxiliary functions to manipulate prototypes and closures
6 ** See Copyright Notice in lua.h
7 */
8
9 #define lfunc_c
10 #define LUA_CORE
11
12 #include "lprefix.h"
13
14
15 #ifndef _KERNEL
16 #include <stddef.h>
17 #endif /* _KERNEL */
18
19 #include "lua.h"
20
21 #include "ldebug.h"
22 #include "ldo.h"
23 #include "lfunc.h"
24 #include "lgc.h"
25 #include "lmem.h"
26 #include "lobject.h"
27 #include "lstate.h"
28
29
30
luaF_newCclosure(lua_State * L,int nupvals)31 CClosure *luaF_newCclosure (lua_State *L, int nupvals) {
32 GCObject *o = luaC_newobj(L, LUA_VCCL, sizeCclosure(nupvals));
33 CClosure *c = gco2ccl(o);
34 c->nupvalues = cast_byte(nupvals);
35 return c;
36 }
37
38
luaF_newLclosure(lua_State * L,int nupvals)39 LClosure *luaF_newLclosure (lua_State *L, int nupvals) {
40 GCObject *o = luaC_newobj(L, LUA_VLCL, sizeLclosure(nupvals));
41 LClosure *c = gco2lcl(o);
42 c->p = NULL;
43 c->nupvalues = cast_byte(nupvals);
44 while (nupvals--) c->upvals[nupvals] = NULL;
45 return c;
46 }
47
48
49 /*
50 ** fill a closure with new closed upvalues
51 */
luaF_initupvals(lua_State * L,LClosure * cl)52 void luaF_initupvals (lua_State *L, LClosure *cl) {
53 int i;
54 for (i = 0; i < cl->nupvalues; i++) {
55 GCObject *o = luaC_newobj(L, LUA_VUPVAL, sizeof(UpVal));
56 UpVal *uv = gco2upv(o);
57 uv->v.p = &uv->u.value; /* make it closed */
58 setnilvalue(uv->v.p);
59 cl->upvals[i] = uv;
60 luaC_objbarrier(L, cl, uv);
61 }
62 }
63
64
65 /*
66 ** Create a new upvalue at the given level, and link it to the list of
67 ** open upvalues of 'L' after entry 'prev'.
68 **/
newupval(lua_State * L,StkId level,UpVal ** prev)69 static UpVal *newupval (lua_State *L, StkId level, UpVal **prev) {
70 GCObject *o = luaC_newobj(L, LUA_VUPVAL, sizeof(UpVal));
71 UpVal *uv = gco2upv(o);
72 UpVal *next = *prev;
73 uv->v.p = s2v(level); /* current value lives in the stack */
74 uv->u.open.next = next; /* link it to list of open upvalues */
75 uv->u.open.previous = prev;
76 if (next)
77 next->u.open.previous = &uv->u.open.next;
78 *prev = uv;
79 if (!isintwups(L)) { /* thread not in list of threads with upvalues? */
80 L->twups = G(L)->twups; /* link it to the list */
81 G(L)->twups = L;
82 }
83 return uv;
84 }
85
86
87 /*
88 ** Find and reuse, or create if it does not exist, an upvalue
89 ** at the given level.
90 */
luaF_findupval(lua_State * L,StkId level)91 UpVal *luaF_findupval (lua_State *L, StkId level) {
92 UpVal **pp = &L->openupval;
93 UpVal *p;
94 lua_assert(isintwups(L) || L->openupval == NULL);
95 while ((p = *pp) != NULL && uplevel(p) >= level) { /* search for it */
96 lua_assert(!isdead(G(L), p));
97 if (uplevel(p) == level) /* corresponding upvalue? */
98 return p; /* return it */
99 pp = &p->u.open.next;
100 }
101 /* not found: create a new upvalue after 'pp' */
102 return newupval(L, level, pp);
103 }
104
105
106 /*
107 ** Call closing method for object 'obj' with error message 'err'. The
108 ** boolean 'yy' controls whether the call is yieldable.
109 ** (This function assumes EXTRA_STACK.)
110 */
callclosemethod(lua_State * L,TValue * obj,TValue * err,int yy)111 static void callclosemethod (lua_State *L, TValue *obj, TValue *err, int yy) {
112 StkId top = L->top.p;
113 const TValue *tm = luaT_gettmbyobj(L, obj, TM_CLOSE);
114 setobj2s(L, top, tm); /* will call metamethod... */
115 setobj2s(L, top + 1, obj); /* with 'self' as the 1st argument */
116 setobj2s(L, top + 2, err); /* and error msg. as 2nd argument */
117 L->top.p = top + 3; /* add function and arguments */
118 if (yy)
119 luaD_call(L, top, 0);
120 else
121 luaD_callnoyield(L, top, 0);
122 }
123
124
125 /*
126 ** Check whether object at given level has a close metamethod and raise
127 ** an error if not.
128 */
checkclosemth(lua_State * L,StkId level)129 static void checkclosemth (lua_State *L, StkId level) {
130 const TValue *tm = luaT_gettmbyobj(L, s2v(level), TM_CLOSE);
131 if (ttisnil(tm)) { /* no metamethod? */
132 int idx = cast_int(level - L->ci->func.p); /* variable index */
133 const char *vname = luaG_findlocal(L, L->ci, idx, NULL);
134 if (vname == NULL) vname = "?";
135 luaG_runerror(L, "variable '%s' got a non-closable value", vname);
136 }
137 }
138
139
140 /*
141 ** Prepare and call a closing method.
142 ** If status is CLOSEKTOP, the call to the closing method will be pushed
143 ** at the top of the stack. Otherwise, values can be pushed right after
144 ** the 'level' of the upvalue being closed, as everything after that
145 ** won't be used again.
146 */
prepcallclosemth(lua_State * L,StkId level,int status,int yy)147 static void prepcallclosemth (lua_State *L, StkId level, int status, int yy) {
148 TValue *uv = s2v(level); /* value being closed */
149 TValue *errobj;
150 if (status == CLOSEKTOP)
151 errobj = &G(L)->nilvalue; /* error object is nil */
152 else { /* 'luaD_seterrorobj' will set top to level + 2 */
153 errobj = s2v(level + 1); /* error object goes after 'uv' */
154 luaD_seterrorobj(L, status, level + 1); /* set error object */
155 }
156 callclosemethod(L, uv, errobj, yy);
157 }
158
159
160 /*
161 ** Maximum value for deltas in 'tbclist', dependent on the type
162 ** of delta. (This macro assumes that an 'L' is in scope where it
163 ** is used.)
164 */
165 #define MAXDELTA \
166 ((256ul << ((sizeof(L->stack.p->tbclist.delta) - 1) * 8)) - 1)
167
168
169 /*
170 ** Insert a variable in the list of to-be-closed variables.
171 */
luaF_newtbcupval(lua_State * L,StkId level)172 void luaF_newtbcupval (lua_State *L, StkId level) {
173 lua_assert(level > L->tbclist.p);
174 if (l_isfalse(s2v(level)))
175 return; /* false doesn't need to be closed */
176 checkclosemth(L, level); /* value must have a close method */
177 while (cast_uint(level - L->tbclist.p) > MAXDELTA) {
178 L->tbclist.p += MAXDELTA; /* create a dummy node at maximum delta */
179 L->tbclist.p->tbclist.delta = 0;
180 }
181 level->tbclist.delta = cast(unsigned short, level - L->tbclist.p);
182 L->tbclist.p = level;
183 }
184
185
luaF_unlinkupval(UpVal * uv)186 void luaF_unlinkupval (UpVal *uv) {
187 lua_assert(upisopen(uv));
188 *uv->u.open.previous = uv->u.open.next;
189 if (uv->u.open.next)
190 uv->u.open.next->u.open.previous = uv->u.open.previous;
191 }
192
193
194 /*
195 ** Close all upvalues up to the given stack level.
196 */
luaF_closeupval(lua_State * L,StkId level)197 void luaF_closeupval (lua_State *L, StkId level) {
198 UpVal *uv;
199 StkId upl; /* stack index pointed by 'uv' */
200 while ((uv = L->openupval) != NULL && (upl = uplevel(uv)) >= level) {
201 TValue *slot = &uv->u.value; /* new position for value */
202 lua_assert(uplevel(uv) < L->top.p);
203 luaF_unlinkupval(uv); /* remove upvalue from 'openupval' list */
204 setobj(L, slot, uv->v.p); /* move value to upvalue slot */
205 uv->v.p = slot; /* now current value lives here */
206 if (!iswhite(uv)) { /* neither white nor dead? */
207 nw2black(uv); /* closed upvalues cannot be gray */
208 luaC_barrier(L, uv, slot);
209 }
210 }
211 }
212
213
214 /*
215 ** Remove first element from the tbclist plus its dummy nodes.
216 */
poptbclist(lua_State * L)217 static void poptbclist (lua_State *L) {
218 StkId tbc = L->tbclist.p;
219 lua_assert(tbc->tbclist.delta > 0); /* first element cannot be dummy */
220 tbc -= tbc->tbclist.delta;
221 while (tbc > L->stack.p && tbc->tbclist.delta == 0)
222 tbc -= MAXDELTA; /* remove dummy nodes */
223 L->tbclist.p = tbc;
224 }
225
226
227 /*
228 ** Close all upvalues and to-be-closed variables up to the given stack
229 ** level. Return restored 'level'.
230 */
luaF_close(lua_State * L,StkId level,int status,int yy)231 StkId luaF_close (lua_State *L, StkId level, int status, int yy) {
232 ptrdiff_t levelrel = savestack(L, level);
233 luaF_closeupval(L, level); /* first, close the upvalues */
234 while (L->tbclist.p >= level) { /* traverse tbc's down to that level */
235 StkId tbc = L->tbclist.p; /* get variable index */
236 poptbclist(L); /* remove it from list */
237 prepcallclosemth(L, tbc, status, yy); /* close variable */
238 level = restorestack(L, levelrel);
239 }
240 return level;
241 }
242
243
luaF_newproto(lua_State * L)244 Proto *luaF_newproto (lua_State *L) {
245 GCObject *o = luaC_newobj(L, LUA_VPROTO, sizeof(Proto));
246 Proto *f = gco2p(o);
247 f->k = NULL;
248 f->sizek = 0;
249 f->p = NULL;
250 f->sizep = 0;
251 f->code = NULL;
252 f->sizecode = 0;
253 f->lineinfo = NULL;
254 f->sizelineinfo = 0;
255 f->abslineinfo = NULL;
256 f->sizeabslineinfo = 0;
257 f->upvalues = NULL;
258 f->sizeupvalues = 0;
259 f->numparams = 0;
260 f->is_vararg = 0;
261 f->maxstacksize = 0;
262 f->locvars = NULL;
263 f->sizelocvars = 0;
264 f->linedefined = 0;
265 f->lastlinedefined = 0;
266 f->source = NULL;
267 return f;
268 }
269
270
luaF_freeproto(lua_State * L,Proto * f)271 void luaF_freeproto (lua_State *L, Proto *f) {
272 luaM_freearray(L, f->code, f->sizecode);
273 luaM_freearray(L, f->p, f->sizep);
274 luaM_freearray(L, f->k, f->sizek);
275 luaM_freearray(L, f->lineinfo, f->sizelineinfo);
276 luaM_freearray(L, f->abslineinfo, f->sizeabslineinfo);
277 luaM_freearray(L, f->locvars, f->sizelocvars);
278 luaM_freearray(L, f->upvalues, f->sizeupvalues);
279 luaM_free(L, f);
280 }
281
282
283 /*
284 ** Look for n-th local variable at line 'line' in function 'func'.
285 ** Returns NULL if not found.
286 */
luaF_getlocalname(const Proto * f,int local_number,int pc)287 const char *luaF_getlocalname (const Proto *f, int local_number, int pc) {
288 int i;
289 for (i = 0; i<f->sizelocvars && f->locvars[i].startpc <= pc; i++) {
290 if (pc < f->locvars[i].endpc) { /* is variable active? */
291 local_number--;
292 if (local_number == 0)
293 return getstr(f->locvars[i].varname);
294 }
295 }
296 return NULL; /* not found */
297 }
298
299