600 lines
18 KiB
C++
600 lines
18 KiB
C++
// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
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// This code is based on Lua 5.x implementation licensed under MIT License; see lua_LICENSE.txt for details
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#include "lvm.h"
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#include "lstate.h"
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#include "lstring.h"
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#include "ltable.h"
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#include "lgc.h"
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#include "ldo.h"
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#include "lnumutils.h"
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#include <string.h>
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// limit for table tag-method chains (to avoid loops)
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#define MAXTAGLOOP 100
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const TValue* luaV_tonumber(const TValue* obj, TValue* n)
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{
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double num;
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if (ttisnumber(obj))
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return obj;
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if (ttisstring(obj) && luaO_str2d(svalue(obj), &num))
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{
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setnvalue(n, num);
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return n;
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}
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else
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return NULL;
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}
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int luaV_tostring(lua_State* L, StkId obj)
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{
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if (!ttisnumber(obj))
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return 0;
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else
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{
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char s[LUAI_MAXNUM2STR];
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double n = nvalue(obj);
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char* e = luai_num2str(s, n);
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LUAU_ASSERT(e < s + sizeof(s));
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setsvalue(L, obj, luaS_newlstr(L, s, e - s));
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return 1;
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}
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}
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const float* luaV_tovector(const TValue* obj)
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{
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if (ttisvector(obj))
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return obj->value.v;
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return nullptr;
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}
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static StkId callTMres(lua_State* L, StkId res, const TValue* f, const TValue* p1, const TValue* p2)
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{
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ptrdiff_t result = savestack(L, res);
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// using stack room beyond top is technically safe here, but for very complicated reasons:
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// * The stack guarantees EXTRA_STACK room beyond stack_last (see luaD_reallocstack) will be allocated
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// * we cannot move luaD_checkstack above because the arguments are *sometimes* pointers to the lua
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// stack and checkstack may invalidate those pointers
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// * we cannot use savestack/restorestack because the arguments are sometimes on the C++ stack
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// * during stack reallocation all of the allocated stack is copied (even beyond stack_last) so these
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// values will be preserved even if they go past stack_last
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LUAU_ASSERT((L->top + 3) < (L->stack + L->stacksize));
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setobj2s(L, L->top, f); // push function
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setobj2s(L, L->top + 1, p1); // 1st argument
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setobj2s(L, L->top + 2, p2); // 2nd argument
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luaD_checkstack(L, 3);
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L->top += 3;
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luaD_call(L, L->top - 3, 1);
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res = restorestack(L, result);
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L->top--;
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setobj2s(L, res, L->top);
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return res;
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}
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static void callTM(lua_State* L, const TValue* f, const TValue* p1, const TValue* p2, const TValue* p3)
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{
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// using stack room beyond top is technically safe here, but for very complicated reasons:
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// * The stack guarantees EXTRA_STACK room beyond stack_last (see luaD_reallocstack) will be allocated
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// * we cannot move luaD_checkstack above because the arguments are *sometimes* pointers to the lua
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// stack and checkstack may invalidate those pointers
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// * we cannot use savestack/restorestack because the arguments are sometimes on the C++ stack
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// * during stack reallocation all of the allocated stack is copied (even beyond stack_last) so these
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// values will be preserved even if they go past stack_last
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LUAU_ASSERT((L->top + 4) < (L->stack + L->stacksize));
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setobj2s(L, L->top, f); // push function
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setobj2s(L, L->top + 1, p1); // 1st argument
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setobj2s(L, L->top + 2, p2); // 2nd argument
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setobj2s(L, L->top + 3, p3); // 3th argument
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luaD_checkstack(L, 4);
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L->top += 4;
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luaD_call(L, L->top - 4, 0);
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}
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void luaV_gettable(lua_State* L, const TValue* t, TValue* key, StkId val)
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{
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int loop;
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for (loop = 0; loop < MAXTAGLOOP; loop++)
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{
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const TValue* tm;
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if (ttistable(t))
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{ // `t' is a table?
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Table* h = hvalue(t);
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const TValue* res = luaH_get(h, key); // do a primitive get
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if (res != luaO_nilobject)
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L->cachedslot = gval2slot(h, res); // remember slot to accelerate future lookups
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if (!ttisnil(res) // result is no nil?
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|| (tm = fasttm(L, h->metatable, TM_INDEX)) == NULL)
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{ // or no TM?
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setobj2s(L, val, res);
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return;
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}
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// t isn't a table, so see if it has an INDEX meta-method to look up the key with
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}
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else if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_INDEX)))
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luaG_indexerror(L, t, key);
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if (ttisfunction(tm))
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{
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callTMres(L, val, tm, t, key);
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return;
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}
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t = tm; // else repeat with `tm'
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}
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luaG_runerror(L, "'__index' chain too long; possible loop");
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}
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void luaV_settable(lua_State* L, const TValue* t, TValue* key, StkId val)
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{
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int loop;
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TValue temp;
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for (loop = 0; loop < MAXTAGLOOP; loop++)
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{
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const TValue* tm;
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if (ttistable(t))
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{ // `t' is a table?
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Table* h = hvalue(t);
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const TValue* oldval = luaH_get(h, key);
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// should we assign the key? (if key is valid or __newindex is not set)
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if (!ttisnil(oldval) || (tm = fasttm(L, h->metatable, TM_NEWINDEX)) == NULL)
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{
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if (h->readonly)
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luaG_readonlyerror(L);
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// luaH_set would work but would repeat the lookup so we use luaH_setslot that can reuse oldval if it's safe
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TValue* newval = luaH_setslot(L, h, oldval, key);
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L->cachedslot = gval2slot(h, newval); // remember slot to accelerate future lookups
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setobj2t(L, newval, val);
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luaC_barriert(L, h, val);
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return;
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}
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// fallthrough to metamethod
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}
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else if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_NEWINDEX)))
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luaG_indexerror(L, t, key);
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if (ttisfunction(tm))
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{
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callTM(L, tm, t, key, val);
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return;
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}
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// else repeat with `tm'
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setobj(L, &temp, tm); // avoid pointing inside table (may rehash)
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t = &temp;
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}
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luaG_runerror(L, "'__newindex' chain too long; possible loop");
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}
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static int call_binTM(lua_State* L, const TValue* p1, const TValue* p2, StkId res, TMS event)
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{
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const TValue* tm = luaT_gettmbyobj(L, p1, event); // try first operand
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if (ttisnil(tm))
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tm = luaT_gettmbyobj(L, p2, event); // try second operand
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if (ttisnil(tm))
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return 0;
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callTMres(L, res, tm, p1, p2);
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return 1;
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}
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static const TValue* get_compTM(lua_State* L, Table* mt1, Table* mt2, TMS event)
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{
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const TValue* tm1 = fasttm(L, mt1, event);
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const TValue* tm2;
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if (tm1 == NULL)
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return NULL; // no metamethod
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if (mt1 == mt2)
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return tm1; // same metatables => same metamethods
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tm2 = fasttm(L, mt2, event);
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if (tm2 == NULL)
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return NULL; // no metamethod
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if (luaO_rawequalObj(tm1, tm2)) // same metamethods?
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return tm1;
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return NULL;
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}
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static int call_orderTM(lua_State* L, const TValue* p1, const TValue* p2, TMS event, bool error = false)
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{
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const TValue* tm1 = luaT_gettmbyobj(L, p1, event);
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const TValue* tm2;
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if (ttisnil(tm1))
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{
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if (error)
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luaG_ordererror(L, p1, p2, event);
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return -1; // no metamethod?
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}
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tm2 = luaT_gettmbyobj(L, p2, event);
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if (!luaO_rawequalObj(tm1, tm2)) // different metamethods?
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{
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if (error)
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luaG_ordererror(L, p1, p2, event);
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return -1;
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}
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callTMres(L, L->top, tm1, p1, p2);
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return !l_isfalse(L->top);
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}
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int luaV_strcmp(const TString* ls, const TString* rs)
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{
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if (ls == rs)
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return 0;
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const char* l = getstr(ls);
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const char* r = getstr(rs);
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// always safe to read one character because even empty strings are nul terminated
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if (*l != *r)
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return uint8_t(*l) - uint8_t(*r);
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size_t ll = ls->len;
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size_t lr = rs->len;
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size_t lmin = ll < lr ? ll : lr;
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int res = memcmp(l, r, lmin);
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if (res != 0)
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return res;
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return ll == lr ? 0 : ll < lr ? -1 : 1;
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}
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int luaV_lessthan(lua_State* L, const TValue* l, const TValue* r)
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{
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if (LUAU_UNLIKELY(ttype(l) != ttype(r)))
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luaG_ordererror(L, l, r, TM_LT);
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else if (LUAU_LIKELY(ttisnumber(l)))
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return luai_numlt(nvalue(l), nvalue(r));
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else if (ttisstring(l))
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return luaV_strcmp(tsvalue(l), tsvalue(r)) < 0;
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else
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return call_orderTM(L, l, r, TM_LT, /* error= */ true);
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}
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int luaV_lessequal(lua_State* L, const TValue* l, const TValue* r)
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{
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int res;
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if (ttype(l) != ttype(r))
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luaG_ordererror(L, l, r, TM_LE);
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else if (ttisnumber(l))
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return luai_numle(nvalue(l), nvalue(r));
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else if (ttisstring(l))
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return luaV_strcmp(tsvalue(l), tsvalue(r)) <= 0;
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else if ((res = call_orderTM(L, l, r, TM_LE)) != -1) // first try `le'
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return res;
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else if ((res = call_orderTM(L, r, l, TM_LT)) == -1) // error if not `lt'
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luaG_ordererror(L, l, r, TM_LE);
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return !res;
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}
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int luaV_equalval(lua_State* L, const TValue* t1, const TValue* t2)
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{
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const TValue* tm;
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LUAU_ASSERT(ttype(t1) == ttype(t2));
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switch (ttype(t1))
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{
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case LUA_TNIL:
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return 1;
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case LUA_TNUMBER:
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return luai_numeq(nvalue(t1), nvalue(t2));
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case LUA_TVECTOR:
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return luai_veceq(vvalue(t1), vvalue(t2));
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case LUA_TBOOLEAN:
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return bvalue(t1) == bvalue(t2); // true must be 1 !!
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case LUA_TLIGHTUSERDATA:
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return pvalue(t1) == pvalue(t2);
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case LUA_TUSERDATA:
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{
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tm = get_compTM(L, uvalue(t1)->metatable, uvalue(t2)->metatable, TM_EQ);
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if (!tm)
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return uvalue(t1) == uvalue(t2);
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break; // will try TM
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}
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case LUA_TTABLE:
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{
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tm = get_compTM(L, hvalue(t1)->metatable, hvalue(t2)->metatable, TM_EQ);
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if (!tm)
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return hvalue(t1) == hvalue(t2);
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break; // will try TM
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}
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default:
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return gcvalue(t1) == gcvalue(t2);
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}
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callTMres(L, L->top, tm, t1, t2); // call TM
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return !l_isfalse(L->top);
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}
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void luaV_concat(lua_State* L, int total, int last)
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{
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do
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{
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StkId top = L->base + last + 1;
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int n = 2; // number of elements handled in this pass (at least 2)
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if (!(ttisstring(top - 2) || ttisnumber(top - 2)) || !tostring(L, top - 1))
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{
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if (!call_binTM(L, top - 2, top - 1, top - 2, TM_CONCAT))
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luaG_concaterror(L, top - 2, top - 1);
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}
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else if (tsvalue(top - 1)->len == 0) // second op is empty?
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(void)tostring(L, top - 2); // result is first op (as string)
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else
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{
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// at least two string values; get as many as possible
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size_t tl = tsvalue(top - 1)->len;
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char* buffer;
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int i;
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// collect total length
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for (n = 1; n < total && tostring(L, top - n - 1); n++)
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{
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size_t l = tsvalue(top - n - 1)->len;
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if (l > MAXSSIZE - tl)
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luaG_runerror(L, "string length overflow");
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tl += l;
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}
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char buf[LUA_BUFFERSIZE];
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TString* ts = nullptr;
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if (tl < LUA_BUFFERSIZE)
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{
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buffer = buf;
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}
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else
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{
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ts = luaS_bufstart(L, tl);
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buffer = ts->data;
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}
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tl = 0;
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for (i = n; i > 0; i--)
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{ // concat all strings
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size_t l = tsvalue(top - i)->len;
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memcpy(buffer + tl, svalue(top - i), l);
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tl += l;
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}
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if (tl < LUA_BUFFERSIZE)
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{
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setsvalue(L, top - n, luaS_newlstr(L, buffer, tl));
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}
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else
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{
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setsvalue(L, top - n, luaS_buffinish(L, ts));
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}
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}
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total -= n - 1; // got `n' strings to create 1 new
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last -= n - 1;
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} while (total > 1); // repeat until only 1 result left
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}
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void luaV_doarith(lua_State* L, StkId ra, const TValue* rb, const TValue* rc, TMS op)
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{
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TValue tempb, tempc;
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const TValue *b, *c;
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if ((b = luaV_tonumber(rb, &tempb)) != NULL && (c = luaV_tonumber(rc, &tempc)) != NULL)
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{
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double nb = nvalue(b), nc = nvalue(c);
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switch (op)
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{
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case TM_ADD:
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setnvalue(ra, luai_numadd(nb, nc));
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break;
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case TM_SUB:
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setnvalue(ra, luai_numsub(nb, nc));
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break;
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case TM_MUL:
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setnvalue(ra, luai_nummul(nb, nc));
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break;
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case TM_DIV:
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setnvalue(ra, luai_numdiv(nb, nc));
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break;
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case TM_MOD:
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setnvalue(ra, luai_nummod(nb, nc));
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break;
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case TM_POW:
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setnvalue(ra, luai_numpow(nb, nc));
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break;
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case TM_UNM:
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setnvalue(ra, luai_numunm(nb));
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break;
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default:
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LUAU_ASSERT(0);
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break;
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}
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}
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else
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{
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// vector operations that we support: v + v, v - v, v * v, s * v, v * s, v / v, s / v, v / s, -v
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const float* vb = luaV_tovector(rb);
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const float* vc = luaV_tovector(rc);
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if (vb && vc)
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{
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switch (op)
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{
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case TM_ADD:
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setvvalue(ra, vb[0] + vc[0], vb[1] + vc[1], vb[2] + vc[2], vb[3] + vc[3]);
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return;
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case TM_SUB:
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setvvalue(ra, vb[0] - vc[0], vb[1] - vc[1], vb[2] - vc[2], vb[3] - vc[3]);
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return;
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case TM_MUL:
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setvvalue(ra, vb[0] * vc[0], vb[1] * vc[1], vb[2] * vc[2], vb[3] * vc[3]);
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return;
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case TM_DIV:
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setvvalue(ra, vb[0] / vc[0], vb[1] / vc[1], vb[2] / vc[2], vb[3] / vc[3]);
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return;
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case TM_UNM:
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setvvalue(ra, -vb[0], -vb[1], -vb[2], -vb[3]);
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return;
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default:
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break;
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}
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}
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else if (vb)
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{
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c = luaV_tonumber(rc, &tempc);
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if (c)
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{
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float nc = cast_to(float, nvalue(c));
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switch (op)
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{
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case TM_MUL:
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setvvalue(ra, vb[0] * nc, vb[1] * nc, vb[2] * nc, vb[3] * nc);
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return;
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case TM_DIV:
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setvvalue(ra, vb[0] / nc, vb[1] / nc, vb[2] / nc, vb[3] / nc);
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return;
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default:
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break;
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}
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}
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}
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else if (vc)
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{
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b = luaV_tonumber(rb, &tempb);
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if (b)
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{
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float nb = cast_to(float, nvalue(b));
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switch (op)
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{
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case TM_MUL:
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setvvalue(ra, nb * vc[0], nb * vc[1], nb * vc[2], nb * vc[3]);
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return;
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case TM_DIV:
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setvvalue(ra, nb / vc[0], nb / vc[1], nb / vc[2], nb / vc[3]);
|
|
return;
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (!call_binTM(L, rb, rc, ra, op))
|
|
{
|
|
luaG_aritherror(L, rb, rc, op);
|
|
}
|
|
}
|
|
}
|
|
|
|
void luaV_dolen(lua_State* L, StkId ra, const TValue* rb)
|
|
{
|
|
const TValue* tm = NULL;
|
|
switch (ttype(rb))
|
|
{
|
|
case LUA_TTABLE:
|
|
{
|
|
Table* h = hvalue(rb);
|
|
if ((tm = fasttm(L, h->metatable, TM_LEN)) == NULL)
|
|
{
|
|
setnvalue(ra, cast_num(luaH_getn(h)));
|
|
return;
|
|
}
|
|
break;
|
|
}
|
|
case LUA_TSTRING:
|
|
{
|
|
TString* ts = tsvalue(rb);
|
|
setnvalue(ra, cast_num(ts->len));
|
|
return;
|
|
}
|
|
default:
|
|
tm = luaT_gettmbyobj(L, rb, TM_LEN);
|
|
}
|
|
|
|
if (ttisnil(tm))
|
|
luaG_typeerror(L, rb, "get length of");
|
|
|
|
StkId res = callTMres(L, ra, tm, rb, luaO_nilobject);
|
|
if (!ttisnumber(res))
|
|
luaG_runerror(L, "'__len' must return a number"); // note, we can't access rb since stack may have been reallocated
|
|
}
|
|
|
|
LUAU_NOINLINE void luaV_prepareFORN(lua_State* L, StkId plimit, StkId pstep, StkId pinit)
|
|
{
|
|
if (!ttisnumber(pinit) && !luaV_tonumber(pinit, pinit))
|
|
luaG_forerror(L, pinit, "initial value");
|
|
if (!ttisnumber(plimit) && !luaV_tonumber(plimit, plimit))
|
|
luaG_forerror(L, plimit, "limit");
|
|
if (!ttisnumber(pstep) && !luaV_tonumber(pstep, pstep))
|
|
luaG_forerror(L, pstep, "step");
|
|
}
|
|
|
|
// calls a C function f with no yielding support; optionally save one resulting value to the res register
|
|
// the function and arguments have to already be pushed to L->top
|
|
LUAU_NOINLINE void luaV_callTM(lua_State* L, int nparams, int res)
|
|
{
|
|
++L->nCcalls;
|
|
|
|
if (L->nCcalls >= LUAI_MAXCCALLS)
|
|
luaD_checkCstack(L);
|
|
|
|
luaD_checkstack(L, LUA_MINSTACK);
|
|
|
|
StkId top = L->top;
|
|
StkId fun = top - nparams - 1;
|
|
|
|
CallInfo* ci = incr_ci(L);
|
|
ci->func = fun;
|
|
ci->base = fun + 1;
|
|
ci->top = top + LUA_MINSTACK;
|
|
ci->savedpc = NULL;
|
|
ci->flags = 0;
|
|
ci->nresults = (res >= 0);
|
|
LUAU_ASSERT(ci->top <= L->stack_last);
|
|
|
|
LUAU_ASSERT(ttisfunction(ci->func));
|
|
LUAU_ASSERT(clvalue(ci->func)->isC);
|
|
|
|
L->base = fun + 1;
|
|
LUAU_ASSERT(L->top == L->base + nparams);
|
|
|
|
lua_CFunction func = clvalue(fun)->c.f;
|
|
int n = func(L);
|
|
LUAU_ASSERT(n >= 0); // yields should have been blocked by nCcalls
|
|
|
|
// ci is our callinfo, cip is our parent
|
|
// note that we read L->ci again since it may have been reallocated by the call
|
|
CallInfo* cip = L->ci - 1;
|
|
|
|
// copy return value into parent stack
|
|
if (res >= 0)
|
|
{
|
|
if (n > 0)
|
|
{
|
|
setobj2s(L, &cip->base[res], L->top - n);
|
|
}
|
|
else
|
|
{
|
|
setnilvalue(&cip->base[res]);
|
|
}
|
|
}
|
|
|
|
L->ci = cip;
|
|
L->base = cip->base;
|
|
L->top = cip->top;
|
|
|
|
--L->nCcalls;
|
|
}
|
|
|
|
LUAU_NOINLINE void luaV_tryfuncTM(lua_State* L, StkId func)
|
|
{
|
|
const TValue* tm = luaT_gettmbyobj(L, func, TM_CALL);
|
|
if (!ttisfunction(tm))
|
|
luaG_typeerror(L, func, "call");
|
|
for (StkId p = L->top; p > func; p--) // open space for metamethod
|
|
setobj2s(L, p, p - 1);
|
|
L->top++; // stack space pre-allocated by the caller
|
|
setobj2s(L, func, tm); // tag method is the new function to be called
|
|
}
|