1 /*
2 ** Function handling (prototypes, functions and upvalues).
3 ** Copyright (C) 2005-2021 Mike Pall. See Copyright Notice in luajit.h
4 **
5 ** Portions taken verbatim or adapted from the Lua interpreter.
6 ** Copyright (C) 1994-2008 Lua.org, PUC-Rio. See Copyright Notice in lua.h
7 */
8
9 #define lj_func_c
10 #define LUA_CORE
11
12 #include "lj_obj.h"
13 #include "lj_gc.h"
14 #include "lj_func.h"
15 #include "lj_trace.h"
16 #include "lj_vm.h"
17
18 /* -- Prototypes ---------------------------------------------------------- */
19
lj_func_freeproto(global_State * g,GCproto * pt)20 void LJ_FASTCALL lj_func_freeproto(global_State *g, GCproto *pt)
21 {
22 lj_mem_free(g, pt, pt->sizept);
23 }
24
25 /* -- Upvalues ------------------------------------------------------------ */
26
unlinkuv(global_State * g,GCupval * uv)27 static void unlinkuv(global_State *g, GCupval *uv)
28 {
29 UNUSED(g);
30 lj_assertG(uvprev(uvnext(uv)) == uv && uvnext(uvprev(uv)) == uv,
31 "broken upvalue chain");
32 setgcrefr(uvnext(uv)->prev, uv->prev);
33 setgcrefr(uvprev(uv)->next, uv->next);
34 }
35
36 /* Find existing open upvalue for a stack slot or create a new one. */
func_finduv(lua_State * L,TValue * slot)37 static GCupval *func_finduv(lua_State *L, TValue *slot)
38 {
39 global_State *g = G(L);
40 GCRef *pp = &L->openupval;
41 GCupval *p;
42 GCupval *uv;
43 /* Search the sorted list of open upvalues. */
44 while (gcref(*pp) != NULL && uvval((p = gco2uv(gcref(*pp)))) >= slot) {
45 lj_assertG(!p->closed && uvval(p) != &p->tv, "closed upvalue in chain");
46 if (uvval(p) == slot) { /* Found open upvalue pointing to same slot? */
47 if (isdead(g, obj2gco(p))) /* Resurrect it, if it's dead. */
48 flipwhite(obj2gco(p));
49 return p;
50 }
51 pp = &p->nextgc;
52 }
53 /* No matching upvalue found. Create a new one. */
54 uv = lj_mem_newt(L, sizeof(GCupval), GCupval);
55 newwhite(g, uv);
56 uv->gct = ~LJ_TUPVAL;
57 uv->closed = 0; /* Still open. */
58 setmref(uv->v, slot); /* Pointing to the stack slot. */
59 /* NOBARRIER: The GCupval is new (marked white) and open. */
60 setgcrefr(uv->nextgc, *pp); /* Insert into sorted list of open upvalues. */
61 setgcref(*pp, obj2gco(uv));
62 setgcref(uv->prev, obj2gco(&g->uvhead)); /* Insert into GC list, too. */
63 setgcrefr(uv->next, g->uvhead.next);
64 setgcref(uvnext(uv)->prev, obj2gco(uv));
65 setgcref(g->uvhead.next, obj2gco(uv));
66 lj_assertG(uvprev(uvnext(uv)) == uv && uvnext(uvprev(uv)) == uv,
67 "broken upvalue chain");
68 return uv;
69 }
70
71 /* Create an empty and closed upvalue. */
func_emptyuv(lua_State * L)72 static GCupval *func_emptyuv(lua_State *L)
73 {
74 GCupval *uv = (GCupval *)lj_mem_newgco(L, sizeof(GCupval));
75 uv->gct = ~LJ_TUPVAL;
76 uv->closed = 1;
77 setnilV(&uv->tv);
78 setmref(uv->v, &uv->tv);
79 return uv;
80 }
81
82 /* Close all open upvalues pointing to some stack level or above. */
lj_func_closeuv(lua_State * L,TValue * level)83 void LJ_FASTCALL lj_func_closeuv(lua_State *L, TValue *level)
84 {
85 GCupval *uv;
86 global_State *g = G(L);
87 while (gcref(L->openupval) != NULL &&
88 uvval((uv = gco2uv(gcref(L->openupval)))) >= level) {
89 GCobj *o = obj2gco(uv);
90 lj_assertG(!isblack(o), "bad black upvalue");
91 lj_assertG(!uv->closed && uvval(uv) != &uv->tv, "closed upvalue in chain");
92 setgcrefr(L->openupval, uv->nextgc); /* No longer in open list. */
93 if (isdead(g, o)) {
94 lj_func_freeuv(g, uv);
95 } else {
96 unlinkuv(g, uv);
97 lj_gc_closeuv(g, uv);
98 }
99 }
100 }
101
lj_func_freeuv(global_State * g,GCupval * uv)102 void LJ_FASTCALL lj_func_freeuv(global_State *g, GCupval *uv)
103 {
104 if (!uv->closed)
105 unlinkuv(g, uv);
106 lj_mem_freet(g, uv);
107 }
108
109 /* -- Functions (closures) ------------------------------------------------ */
110
lj_func_newC(lua_State * L,MSize nelems,GCtab * env)111 GCfunc *lj_func_newC(lua_State *L, MSize nelems, GCtab *env)
112 {
113 GCfunc *fn = (GCfunc *)lj_mem_newgco(L, sizeCfunc(nelems));
114 fn->c.gct = ~LJ_TFUNC;
115 fn->c.ffid = FF_C;
116 fn->c.nupvalues = (uint8_t)nelems;
117 /* NOBARRIER: The GCfunc is new (marked white). */
118 setmref(fn->c.pc, &G(L)->bc_cfunc_ext);
119 setgcref(fn->c.env, obj2gco(env));
120 return fn;
121 }
122
func_newL(lua_State * L,GCproto * pt,GCtab * env)123 static GCfunc *func_newL(lua_State *L, GCproto *pt, GCtab *env)
124 {
125 uint32_t count;
126 GCfunc *fn = (GCfunc *)lj_mem_newgco(L, sizeLfunc((MSize)pt->sizeuv));
127 fn->l.gct = ~LJ_TFUNC;
128 fn->l.ffid = FF_LUA;
129 fn->l.nupvalues = 0; /* Set to zero until upvalues are initialized. */
130 /* NOBARRIER: Really a setgcref. But the GCfunc is new (marked white). */
131 setmref(fn->l.pc, proto_bc(pt));
132 setgcref(fn->l.env, obj2gco(env));
133 /* Saturating 3 bit counter (0..7) for created closures. */
134 count = (uint32_t)pt->flags + PROTO_CLCOUNT;
135 pt->flags = (uint8_t)(count - ((count >> PROTO_CLC_BITS) & PROTO_CLCOUNT));
136 return fn;
137 }
138
139 /* Create a new Lua function with empty upvalues. */
lj_func_newL_empty(lua_State * L,GCproto * pt,GCtab * env)140 GCfunc *lj_func_newL_empty(lua_State *L, GCproto *pt, GCtab *env)
141 {
142 GCfunc *fn = func_newL(L, pt, env);
143 MSize i, nuv = pt->sizeuv;
144 /* NOBARRIER: The GCfunc is new (marked white). */
145 for (i = 0; i < nuv; i++) {
146 GCupval *uv = func_emptyuv(L);
147 int32_t v = proto_uv(pt)[i];
148 uv->immutable = ((v / PROTO_UV_IMMUTABLE) & 1);
149 uv->dhash = (uint32_t)(uintptr_t)pt ^ (v << 24);
150 setgcref(fn->l.uvptr[i], obj2gco(uv));
151 }
152 fn->l.nupvalues = (uint8_t)nuv;
153 return fn;
154 }
155
156 /* Do a GC check and create a new Lua function with inherited upvalues. */
lj_func_newL_gc(lua_State * L,GCproto * pt,GCfuncL * parent)157 GCfunc *lj_func_newL_gc(lua_State *L, GCproto *pt, GCfuncL *parent)
158 {
159 GCfunc *fn;
160 GCRef *puv;
161 MSize i, nuv;
162 TValue *base;
163 lj_gc_check_fixtop(L);
164 fn = func_newL(L, pt, tabref(parent->env));
165 /* NOBARRIER: The GCfunc is new (marked white). */
166 puv = parent->uvptr;
167 nuv = pt->sizeuv;
168 base = L->base;
169 for (i = 0; i < nuv; i++) {
170 uint32_t v = proto_uv(pt)[i];
171 GCupval *uv;
172 if ((v & PROTO_UV_LOCAL)) {
173 uv = func_finduv(L, base + (v & 0xff));
174 uv->immutable = ((v / PROTO_UV_IMMUTABLE) & 1);
175 uv->dhash = (uint32_t)(uintptr_t)mref(parent->pc, char) ^ (v << 24);
176 } else {
177 uv = &gcref(puv[v])->uv;
178 }
179 setgcref(fn->l.uvptr[i], obj2gco(uv));
180 }
181 fn->l.nupvalues = (uint8_t)nuv;
182 return fn;
183 }
184
lj_func_free(global_State * g,GCfunc * fn)185 void LJ_FASTCALL lj_func_free(global_State *g, GCfunc *fn)
186 {
187 MSize size = isluafunc(fn) ? sizeLfunc((MSize)fn->l.nupvalues) :
188 sizeCfunc((MSize)fn->c.nupvalues);
189 lj_mem_free(g, fn, size);
190 }
191
192