ljx

lj_func.c (7860B)

---

 /*
 ** Function handling (prototypes, functions and upvalues).
 ** Copyright (C) 2005-2016 Mike Pall. See Copyright Notice in luajit.h
 **
 ** Upvalue handling rewrite and closure lifting.
 ** Copyright (C) 2014 Karel Tuma. See Copyright Notice in luajit.h
 **
 ** Portions taken verbatim or adapted from the Lua interpreter.
 ** Copyright (C) 1994-2008 Lua.org, PUC-Rio. See Copyright Notice in lua.h
 */
 
 #define lj_func_c
 #define LUA_CORE
 
 #include "lj_obj.h"
 #include "lj_gc.h"
 #include "lj_func.h"
 #include "lj_trace.h"
 #include "lj_vm.h"
 
 /* -- Prototypes ---------------------------------------------------------- */
 
 void LJ_FASTCALL lj_func_freeproto(global_State *g, GCproto *pt)
 {
   lj_mem_free(g, pt, pt->sizept);
 }
 
 /* -- Upvalues ------------------------------------------------------------ */
 
 static void unlinkuv(GCupval *uv)
 {
   lua_assert(uvprev(uvnext(uv)) == uv && uvnext(uvprev(uv)) == uv);
   setgcrefr(uvnext(uv)->prev, uv->prev);
   setgcrefr(uvprev(uv)->next, uv->next);
 }
 
 /* Find existing open upvalue for a stack slot or create a new one. */
 static GCupval *func_finduv(lua_State *L, TValue *slot)
 {
   global_State *g = G(L);
   GCRef *pp = &L->openupval;
   GCupval *p;
   GCupval *uv;
   /* Search the sorted list of open upvalues. */
   while (gcref(*pp) != NULL && uvval((p = gco2uv(gcref(*pp)))) >= slot) {
     lua_assert(!p->closed && uvval(p) != &p->tv);
     if (uvval(p) == slot) {  /* Found open upvalue pointing to same slot? */
       if (isdead(g, obj2gco(p)))  /* Resurrect it, if it's dead. */
 	flipwhite(obj2gco(p));
       return p;
     }
     pp = &p->nextgc;
   }
   /* No matching upvalue found. Create a new one. */
   uv = lj_mem_newt(L, sizeof(GCupval), GCupval);
   newwhite(g, uv);
   uv->gct = ~LJ_TUPVAL;
   uv->closed = 0;  /* Still open. */
   setmref(uv->v, slot);  /* Pointing to the stack slot. */
   /* NOBARRIER: The GCupval is new (marked white) and open. */
   setgcrefr(uv->nextgc, *pp);  /* Insert into sorted list of open upvalues. */
   setgcref(*pp, obj2gco(uv));
   setgcref(uv->prev, obj2gco(&g->uvhead));  /* Insert into GC list, too. */
   setgcrefr(uv->next, g->uvhead.next);
   setgcref(uvnext(uv)->prev, obj2gco(uv));
   setgcref(g->uvhead.next, obj2gco(uv));
   lua_assert(uvprev(uvnext(uv)) == uv && uvnext(uvprev(uv)) == uv);
   return uv;
 }
 
 /* Create an empty and closed upvalue. */
 static GCupval *func_emptyuv(lua_State *L)
 {
   GCupval *uv = (GCupval *)lj_mem_newgco(L, sizeof(GCupval));
   uv->gct = ~LJ_TUPVAL;
   uv->closed = 1;
   setnilV(&uv->tv);
   setmref(uv->v, &uv->tv);
   return uv;
 }
 
 /* Close all open upvalues pointing to some stack level or above. */
 void LJ_FASTCALL lj_func_closeuv(lua_State *L, TValue *level)
 {
   GCupval *uv;
   global_State *g = G(L);
   while (gcref(L->openupval) != NULL &&
 	 uvval((uv = gco2uv(gcref(L->openupval)))) >= level) {
     GCobj *o = obj2gco(uv);
     lua_assert(!isblack(o) && !uv->closed && uvval(uv) != &uv->tv);
     setgcrefr(L->openupval, uv->nextgc);  /* No longer in open list. */
     if (isdead(g, o)) {
       lj_func_freeuv(g, uv);
     } else {
       unlinkuv(uv);
       lj_gc_closeuv(g, uv);
     }
   }
 }
 
 void LJ_FASTCALL lj_func_freeuv(global_State *g, GCupval *uv)
 {
   if (!uv->closed)
     unlinkuv(uv);
   lj_mem_freet(g, uv);
 }
 
 /* -- Functions (closures) ------------------------------------------------ */
 
 GCfunc *lj_func_newC(lua_State *L, MSize nelems, GCtab *env)
 {
   GCfunc *fn = (GCfunc *)lj_mem_newgco(L, sizeCfunc(nelems));
   fn->c.gct = ~LJ_TFUNC;
   fn->c.ffid = FF_C;
   fn->c.nupvalues = (uint8_t)nelems;
   /* NOBARRIER: The GCfunc is new (marked white). */
   setmref(fn->c.pc, &G(L)->bc_cfunc_ext);
   setgcref(fn->c.env, obj2gco(env));
   return fn;
 }
 
 static GCfunc *func_newL(lua_State *L, GCproto *pt, GCtab *env)
 {
   uint32_t count;
   GCfunc *fn = (GCfunc *)lj_mem_newgco(L, sizeLfunc((MSize)pt->sizeuv));
   /* Initially points to itself */
   setgcref(fn->l.prev_ENV, obj2gco(fn));
   setgcref(fn->l.next_ENV, obj2gco(fn));
   fn->l.gct = ~LJ_TFUNC;
   fn->l.ffid = FF_LUA;
   fn->l.nupvalues = 0;  /* Set to zero until upvalues are initialized. */
   /* NOBARRIER: Really a setgcref. But the GCfunc is new (marked white). */
   setmref(fn->l.pc, proto_bc(pt));
   setgcref(fn->l.env, obj2gco(env));
   /* Saturating 3 bit counter (0..7) for created closures. */
   count = (uint32_t)pt->flags + PROTO_CLCOUNT;
   pt->flags = (uint8_t)(count - ((count >> PROTO_CLC_BITS) & PROTO_CLCOUNT));
   return fn;
 }
 
 static GCfunc *lj_func_newL(lua_State *L, GCproto *pt, GCfuncL *parent);
 /* Recursively instantiate closures */
 static inline
 void lj_func_init_closure(lua_State *L, uintptr_t i, GCproto *pttab, GCfuncL *parent, GCupval *uv)
 {
   setfuncV(L, &uv->tv, lj_func_newL(L, &proto_kgc(pttab, (~i))->pt, parent));
 }
 
 /* Create a new Lua function with empty upvalues. */
 GCfunc *lj_func_newL_empty(lua_State *L, GCproto *pt, GCtab *env)
 {
   GCfunc *fn = func_newL(L, pt, env);
   MSize i, nuv = pt->sizeuv;
   for (i = 0; i < nuv; i++) {
     GCupval *uv = func_emptyuv(L);
     uint32_t v = proto_uv(pt)[i];
     uint8_t flags = (v >> PROTO_UV_SHIFT);
     if (flags == UV_HOLE) {
       setgcrefnull(fn->l.uvptr[i]);
       continue;
     }
     uv->flags = flags;
     uv->dhash = (uint32_t)(uintptr_t)pt ^ ((uint32_t)proto_uv(pt)[i] << 24);
     /* NOBARRIER: The GCfunc is new (marked white). */
     setgcref(fn->l.uvptr[i], obj2gco(uv));
     /* TBD: sub-closures and env barriers? */
     if (flags == UV_ENV) {
       settabV(L, &uv->tv, env);
     } else if (flags == UV_CLOSURE)
       lj_func_init_closure(L, v & PROTO_UV_MASK, pt, &fn->l, uv);
   }
   fn->l.nupvalues = (uint8_t)nuv;
   return fn;
 }
 
 /* Do a GC check and create a new Lua function with inherited upvalues. */
 static GCfunc *lj_func_newL(lua_State *L, GCproto *pt, GCfuncL *parent)
 {
   GCfunc *fn;
   GCRef *puv;
   MSize i, nuv;
   TValue *base;
 
   fn = func_newL(L, pt, tabref(parent->env));
   /* NOBARRIER: The GCfunc is new (marked white). */
   puv = parent->uvptr;
   nuv = pt->sizeuv;
   base = L->base;
 
   fn->l.nupvalues = 0;
   /* TBD: sub-closures and env barriers? */
   for (i = 0; i < nuv; i++) {
     uint32_t v = proto_uv(pt)[i];
     GCupval *uv;
     switch (v >> PROTO_UV_SHIFT) {
       case UV_CLOSURE:
         uv = func_emptyuv(L);
         uv->flags = v >> PROTO_UV_SHIFT;
         setgcref(fn->l.uvptr[i], obj2gco(uv));
         lj_func_init_closure(L, v & PROTO_UV_MASK, pt, &fn->l, uv);
         break;
       case UV_ENV:
         //lua_assert(0);
       case UV_CHAINED:
         uv = &gcref(puv[v & PROTO_UV_MASK])->uv;
         lua_assert(uv);
         if (uv->flags & UV_ENV) {
           setgcref(fn->l.next_ENV, obj2gco(parent));
           fn->l.prev_ENV = parent->prev_ENV;
           setgcref(gcref(fn->l.prev_ENV)->fn.l.next_ENV, obj2gco(fn));
           setgcref(parent->prev_ENV, obj2gco(fn));
         }
         setgcref(fn->l.uvptr[i], obj2gco(uv));
         break;
       case UV_IMMUTABLE:
       case UV_LOCAL:
         uv = func_finduv(L, base + (v & 0xff));
         uv->flags = v >> PROTO_UV_SHIFT;
         uv->dhash = (uint32_t)(uintptr_t)mref(parent->pc, char) ^ (v << 24);
         setgcref(fn->l.uvptr[i], obj2gco(uv));
         break;
       case UV_HOLE:
         setgcrefnull(fn->l.uvptr[i]);
         continue;
       default:
         lua_assert(0);
     }
   }
   fn->l.nupvalues = (uint8_t)nuv;
   return fn;
 }
   
 GCfunc *lj_func_newL_gc(lua_State *L, GCproto *pt, GCfuncL *parent)
 {
   lj_gc_check_fixtop(L);
   return lj_func_newL(L, pt, parent);
 }
 
 void LJ_FASTCALL lj_func_free(global_State *g, GCfunc *fn)
 {
   MSize size = isluafunc(fn) ? sizeLfunc((MSize)fn->l.nupvalues) :
 			       sizeCfunc((MSize)fn->c.nupvalues);
   /* NOBARRIER: Should be handled in ESETV/lua_setupvalue. */
   if (isluafunc(fn)) {
     setgcrefr(gcref(fn->l.next_ENV)->fn.l.prev_ENV, fn->l.prev_ENV);
     setgcrefr(gcref(fn->l.prev_ENV)->fn.l.next_ENV, fn->l.next_ENV);
   }
   lj_mem_free(g, fn, size);
 }