diff options
Diffstat (limited to 'src/lvm.c')
| -rw-r--r-- | src/lvm.c | 256 |
1 files changed, 174 insertions, 82 deletions
@@ -1,5 +1,5 @@ /* -** $Id: lvm.c,v 2.232 2014/12/27 20:30:38 roberto Exp $ +** $Id: lvm.c,v 2.245 2015/06/09 15:53:35 roberto Exp $ ** Lua virtual machine ** See Copyright Notice in lua.h */ @@ -9,8 +9,9 @@ #include "lprefix.h" - +#include <float.h> #include <limits.h> +#include <math.h> #include <stdio.h> #include <stdlib.h> #include <string.h> @@ -30,36 +31,38 @@ #include "lvm.h" -/* -** You can define LUA_FLOORN2I if you want to convert floats to integers -** by flooring them (instead of raising an error if they are not -** integral values) -*/ -#if !defined(LUA_FLOORN2I) -#define LUA_FLOORN2I 0 -#endif - - /* limit for table tag-method chains (to avoid loops) */ #define MAXTAGLOOP 2000 + /* -** Similar to 'tonumber', but does not attempt to convert strings and -** ensure correct precision (no extra bits). Used in comparisons. +** 'l_intfitsf' checks whether a given integer can be converted to a +** float without rounding. Used in comparisons. Left undefined if +** all integers fit in a float precisely. */ -static int tofloat (const TValue *obj, lua_Number *n) { - if (ttisfloat(obj)) *n = fltvalue(obj); - else if (ttisinteger(obj)) { - volatile lua_Number x = cast_num(ivalue(obj)); /* avoid extra precision */ - *n = x; - } - else { - *n = 0; /* to avoid warnings */ - return 0; - } - return 1; -} +#if !defined(l_intfitsf) + +/* number of bits in the mantissa of a float */ +#define NBM (l_mathlim(MANT_DIG)) + +/* +** Check whether some integers may not fit in a float, that is, whether +** (maxinteger >> NBM) > 0 (that implies (1 << NBM) <= maxinteger). +** (The shifts are done in parts to avoid shifting by more than the size +** of an integer. In a worst case, NBM == 113 for long double and +** sizeof(integer) == 32.) +*/ +#if ((((LUA_MAXINTEGER >> (NBM / 4)) >> (NBM / 4)) >> (NBM / 4)) \ + >> (NBM - (3 * (NBM / 4)))) > 0 + +#define l_intfitsf(i) \ + (-((lua_Integer)1 << NBM) <= (i) && (i) <= ((lua_Integer)1 << NBM)) + +#endif + +#endif + /* @@ -73,7 +76,7 @@ int luaV_tonumber_ (const TValue *obj, lua_Number *n) { return 1; } else if (cvt2num(obj) && /* string convertible to number? */ - luaO_str2num(svalue(obj), &v) == tsvalue(obj)->len + 1) { + luaO_str2num(svalue(obj), &v) == vslen(obj) + 1) { *n = nvalue(&v); /* convert result of 'luaO_str2num' to a float */ return 1; } @@ -88,7 +91,7 @@ int luaV_tonumber_ (const TValue *obj, lua_Number *n) { ** mode == 1: takes the floor of the number ** mode == 2: takes the ceil of the number */ -static int tointeger_aux (const TValue *obj, lua_Integer *p, int mode) { +int luaV_tointeger (const TValue *obj, lua_Integer *p, int mode) { TValue v; again: if (ttisfloat(obj)) { @@ -106,7 +109,7 @@ static int tointeger_aux (const TValue *obj, lua_Integer *p, int mode) { return 1; } else if (cvt2num(obj) && - luaO_str2num(svalue(obj), &v) == tsvalue(obj)->len + 1) { + luaO_str2num(svalue(obj), &v) == vslen(obj) + 1) { obj = &v; goto again; /* convert result from 'luaO_str2num' to an integer */ } @@ -115,14 +118,6 @@ static int tointeger_aux (const TValue *obj, lua_Integer *p, int mode) { /* -** try to convert a value to an integer -*/ -int luaV_tointeger_ (const TValue *obj, lua_Integer *p) { - return tointeger_aux(obj, p, LUA_FLOORN2I); -} - - -/* ** Try to convert a 'for' limit to an integer, preserving the ** semantics of the loop. ** (The following explanation assumes a non-negative step; it is valid @@ -140,11 +135,11 @@ int luaV_tointeger_ (const TValue *obj, lua_Integer *p) { static int forlimit (const TValue *obj, lua_Integer *p, lua_Integer step, int *stopnow) { *stopnow = 0; /* usually, let loops run */ - if (!tointeger_aux(obj, p, (step < 0 ? 2 : 1))) { /* not fit in integer? */ + if (!luaV_tointeger(obj, p, (step < 0 ? 2 : 1))) { /* not fit in integer? */ lua_Number n; /* try to convert to float */ if (!tonumber(obj, &n)) /* cannot convert to float? */ return 0; /* not a number */ - if (n > 0) { /* if true, float is larger than max integer */ + if (luai_numlt(0, n)) { /* if true, float is larger than max integer */ *p = LUA_MAXINTEGER; if (step < 0) *stopnow = 1; } @@ -239,9 +234,9 @@ void luaV_settable (lua_State *L, const TValue *t, TValue *key, StkId val) { */ static int l_strcmp (const TString *ls, const TString *rs) { const char *l = getstr(ls); - size_t ll = ls->len; + size_t ll = tsslen(ls); const char *r = getstr(rs); - size_t lr = rs->len; + size_t lr = tsslen(rs); for (;;) { /* for each segment */ int temp = strcoll(l, r); if (temp != 0) /* not equal? */ @@ -261,15 +256,102 @@ static int l_strcmp (const TString *ls, const TString *rs) { /* +** Check whether integer 'i' is less than float 'f'. If 'i' has an +** exact representation as a float ('l_intfitsf'), compare numbers as +** floats. Otherwise, if 'f' is outside the range for integers, result +** is trivial. Otherwise, compare them as integers. (When 'i' has no +** float representation, either 'f' is "far away" from 'i' or 'f' has +** no precision left for a fractional part; either way, how 'f' is +** truncated is irrelevant.) When 'f' is NaN, comparisons must result +** in false. +*/ +static int LTintfloat (lua_Integer i, lua_Number f) { +#if defined(l_intfitsf) + if (!l_intfitsf(i)) { + if (f >= -cast_num(LUA_MININTEGER)) /* -minint == maxint + 1 */ + return 1; /* f >= maxint + 1 > i */ + else if (f > cast_num(LUA_MININTEGER)) /* minint < f <= maxint ? */ + return (i < cast(lua_Integer, f)); /* compare them as integers */ + else /* f <= minint <= i (or 'f' is NaN) --> not(i < f) */ + return 0; + } +#endif + return luai_numlt(cast_num(i), f); /* compare them as floats */ +} + + +/* +** Check whether integer 'i' is less than or equal to float 'f'. +** See comments on previous function. +*/ +static int LEintfloat (lua_Integer i, lua_Number f) { +#if defined(l_intfitsf) + if (!l_intfitsf(i)) { + if (f >= -cast_num(LUA_MININTEGER)) /* -minint == maxint + 1 */ + return 1; /* f >= maxint + 1 > i */ + else if (f >= cast_num(LUA_MININTEGER)) /* minint <= f <= maxint ? */ + return (i <= cast(lua_Integer, f)); /* compare them as integers */ + else /* f < minint <= i (or 'f' is NaN) --> not(i <= f) */ + return 0; + } +#endif + return luai_numle(cast_num(i), f); /* compare them as floats */ +} + + +/* +** Return 'l < r', for numbers. +*/ +static int LTnum (const TValue *l, const TValue *r) { + if (ttisinteger(l)) { + lua_Integer li = ivalue(l); + if (ttisinteger(r)) + return li < ivalue(r); /* both are integers */ + else /* 'l' is int and 'r' is float */ + return LTintfloat(li, fltvalue(r)); /* l < r ? */ + } + else { + lua_Number lf = fltvalue(l); /* 'l' must be float */ + if (ttisfloat(r)) + return luai_numlt(lf, fltvalue(r)); /* both are float */ + else if (luai_numisnan(lf)) /* 'r' is int and 'l' is float */ + return 0; /* NaN < i is always false */ + else /* without NaN, (l < r) <--> not(r <= l) */ + return !LEintfloat(ivalue(r), lf); /* not (r <= l) ? */ + } +} + + +/* +** Return 'l <= r', for numbers. +*/ +static int LEnum (const TValue *l, const TValue *r) { + if (ttisinteger(l)) { + lua_Integer li = ivalue(l); + if (ttisinteger(r)) + return li <= ivalue(r); /* both are integers */ + else /* 'l' is int and 'r' is float */ + return LEintfloat(li, fltvalue(r)); /* l <= r ? */ + } + else { + lua_Number lf = fltvalue(l); /* 'l' must be float */ + if (ttisfloat(r)) + return luai_numle(lf, fltvalue(r)); /* both are float */ + else if (luai_numisnan(lf)) /* 'r' is int and 'l' is float */ + return 0; /* NaN <= i is always false */ + else /* without NaN, (l <= r) <--> not(r < l) */ + return !LTintfloat(ivalue(r), lf); /* not (r < l) ? */ + } +} + + +/* ** Main operation less than; return 'l < r'. */ int luaV_lessthan (lua_State *L, const TValue *l, const TValue *r) { int res; - lua_Number nl, nr; - if (ttisinteger(l) && ttisinteger(r)) /* both operands are integers? */ - return (ivalue(l) < ivalue(r)); - else if (tofloat(l, &nl) && tofloat(r, &nr)) /* both are numbers? */ - return luai_numlt(nl, nr); + if (ttisnumber(l) && ttisnumber(r)) /* both operands are numbers? */ + return LTnum(l, r); else if (ttisstring(l) && ttisstring(r)) /* both are strings? */ return l_strcmp(tsvalue(l), tsvalue(r)) < 0; else if ((res = luaT_callorderTM(L, l, r, TM_LT)) < 0) /* no metamethod? */ @@ -279,27 +361,34 @@ int luaV_lessthan (lua_State *L, const TValue *l, const TValue *r) { /* -** Main operation less than or equal to; return 'l <= r'. +** Main operation less than or equal to; return 'l <= r'. If it needs +** a metamethod and there is no '__le', try '__lt', based on +** l <= r iff !(r < l) (assuming a total order). If the metamethod +** yields during this substitution, the continuation has to know +** about it (to negate the result of r<l); bit CIST_LEQ in the call +** status keeps that information. */ int luaV_lessequal (lua_State *L, const TValue *l, const TValue *r) { int res; - lua_Number nl, nr; - if (ttisinteger(l) && ttisinteger(r)) /* both operands are integers? */ - return (ivalue(l) <= ivalue(r)); - else if (tofloat(l, &nl) && tofloat(r, &nr)) /* both are numbers? */ - return luai_numle(nl, nr); + if (ttisnumber(l) && ttisnumber(r)) /* both operands are numbers? */ + return LEnum(l, r); else if (ttisstring(l) && ttisstring(r)) /* both are strings? */ return l_strcmp(tsvalue(l), tsvalue(r)) <= 0; - else if ((res = luaT_callorderTM(L, l, r, TM_LE)) >= 0) /* first try 'le' */ + else if ((res = luaT_callorderTM(L, l, r, TM_LE)) >= 0) /* try 'le' */ return res; - else if ((res = luaT_callorderTM(L, r, l, TM_LT)) < 0) /* else try 'lt' */ - luaG_ordererror(L, l, r); - return !res; + else { /* try 'lt': */ + L->ci->callstatus |= CIST_LEQ; /* mark it is doing 'lt' for 'le' */ + res = luaT_callorderTM(L, r, l, TM_LT); + L->ci->callstatus ^= CIST_LEQ; /* clear mark */ + if (res < 0) + luaG_ordererror(L, l, r); + return !res; /* result is negated */ + } } /* -** Main operation for equality of Lua values; return 't1 == t2'. +** Main operation for equality of Lua values; return 't1 == t2'. ** L == NULL means raw equality (no metamethods) */ int luaV_equalobj (lua_State *L, const TValue *t1, const TValue *t2) { @@ -308,10 +397,8 @@ int luaV_equalobj (lua_State *L, const TValue *t1, const TValue *t2) { if (ttnov(t1) != ttnov(t2) || ttnov(t1) != LUA_TNUMBER) return 0; /* only numbers can be equal with different variants */ else { /* two numbers with different variants */ - lua_Number n1, n2; /* compare them as floats */ - lua_assert(ttisnumber(t1) && ttisnumber(t2)); - cast_void(tofloat(t1, &n1)); cast_void(tofloat(t2, &n2)); - return luai_numeq(n1, n2); + lua_Integer i1, i2; /* compare them as integers */ + return (tointeger(t1, &i1) && tointeger(t2, &i2) && i1 == i2); } } /* values have same type and same variant */ @@ -354,6 +441,8 @@ int luaV_equalobj (lua_State *L, const TValue *t1, const TValue *t2) { #define tostring(L,o) \ (ttisstring(o) || (cvt2str(o) && (luaO_tostring(L, o), 1))) +#define isemptystr(o) (ttisshrstring(o) && tsvalue(o)->shrlen == 0) + /* ** Main operation for concatenation: concat 'total' values in the stack, ** from 'L->top - total' up to 'L->top - 1'. @@ -365,19 +454,19 @@ void luaV_concat (lua_State *L, int total) { int n = 2; /* number of elements handled in this pass (at least 2) */ if (!(ttisstring(top-2) || cvt2str(top-2)) || !tostring(L, top-1)) luaT_trybinTM(L, top-2, top-1, top-2, TM_CONCAT); - else if (tsvalue(top-1)->len == 0) /* second operand is empty? */ + else if (isemptystr(top - 1)) /* second operand is empty? */ cast_void(tostring(L, top - 2)); /* result is first operand */ - else if (ttisstring(top-2) && tsvalue(top-2)->len == 0) { + else if (isemptystr(top - 2)) { /* first operand is an empty string? */ setobjs2s(L, top - 2, top - 1); /* result is second op. */ } else { /* at least two non-empty string values; get as many as possible */ - size_t tl = tsvalue(top-1)->len; + size_t tl = vslen(top - 1); char *buffer; int i; /* collect total length */ for (i = 1; i < total && tostring(L, top-i-1); i++) { - size_t l = tsvalue(top-i-1)->len; + size_t l = vslen(top - i - 1); if (l >= (MAX_SIZE/sizeof(char)) - tl) luaG_runerror(L, "string length overflow"); tl += l; @@ -386,7 +475,7 @@ void luaV_concat (lua_State *L, int total) { tl = 0; n = i; do { /* copy all strings to buffer */ - size_t l = tsvalue(top-i)->len; + size_t l = vslen(top - i); memcpy(buffer+tl, svalue(top-i), l * sizeof(char)); tl += l; } while (--i > 0); @@ -403,7 +492,7 @@ void luaV_concat (lua_State *L, int total) { */ void luaV_objlen (lua_State *L, StkId ra, const TValue *rb) { const TValue *tm; - switch (ttnov(rb)) { + switch (ttype(rb)) { case LUA_TTABLE: { Table *h = hvalue(rb); tm = fasttm(L, h->metatable, TM_LEN); @@ -411,8 +500,12 @@ void luaV_objlen (lua_State *L, StkId ra, const TValue *rb) { setivalue(ra, luaH_getn(h)); /* else primitive len */ return; } - case LUA_TSTRING: { - setivalue(ra, tsvalue(rb)->len); + case LUA_TSHRSTR: { + setivalue(ra, tsvalue(rb)->shrlen); + return; + } + case LUA_TLNGSTR: { + setivalue(ra, tsvalue(rb)->u.lnglen); return; } default: { /* try metamethod */ @@ -448,7 +541,7 @@ lua_Integer luaV_div (lua_State *L, lua_Integer m, lua_Integer n) { /* -** Integer modulus; return 'm % n'. (Assume that C '%' with +** Integer modulus; return 'm % n'. (Assume that C '%' with ** negative operands follows C99 behavior. See previous comment ** about luaV_div.) */ @@ -553,11 +646,11 @@ void luaV_finishOp (lua_State *L) { case OP_LE: case OP_LT: case OP_EQ: { int res = !l_isfalse(L->top - 1); L->top--; - /* metamethod should not be called when operand is K */ - lua_assert(!ISK(GETARG_B(inst))); - if (op == OP_LE && /* "<=" using "<" instead? */ - ttisnil(luaT_gettmbyobj(L, base + GETARG_B(inst), TM_LE))) - res = !res; /* invert result */ + if (ci->callstatus & CIST_LEQ) { /* "<=" using "<" instead? */ + lua_assert(op == OP_LE); + ci->callstatus ^= CIST_LEQ; /* clear mark */ + res = !res; /* negate result */ + } lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_JMP); if (res != GETARG_A(inst)) /* condition failed? */ ci->u.l.savedpc++; /* skip jump instruction */ @@ -607,7 +700,7 @@ void luaV_finishOp (lua_State *L) { ** some macros for common tasks in 'luaV_execute' */ -#if !defined luai_runtimecheck +#if !defined(luai_runtimecheck) #define luai_runtimecheck(L, c) /* void */ #endif @@ -743,7 +836,7 @@ void luaV_execute (lua_State *L) { Protect(luaV_gettable(L, rb, RKC(i), ra)); vmbreak; } - vmcase(OP_ADD) { + vmcase(OP_ADD) { TValue *rb = RKB(i); TValue *rc = RKC(i); lua_Number nb; lua_Number nc; @@ -928,7 +1021,7 @@ void luaV_execute (lua_State *L) { L->top = base + c + 1; /* mark the end of concat operands */ Protect(luaV_concat(L, c - b + 1)); ra = RA(i); /* 'luav_concat' may invoke TMs and move the stack */ - rb = b + base; + rb = base + b; setobjs2s(L, ra, rb); checkGC(L, (ra >= rb ? ra + 1 : rb)); L->top = ci->top; /* restore top */ @@ -1031,9 +1124,8 @@ void luaV_execute (lua_State *L) { } vmcase(OP_RETURN) { int b = GETARG_B(i); - if (b != 0) L->top = ra+b-1; if (cl->p->sizep > 0) luaF_close(L, base); - b = luaD_poscall(L, ra); + b = luaD_poscall(L, ra, (b != 0 ? b - 1 : L->top - ra)); if (!(ci->callstatus & CIST_REENTRY)) /* 'ci' still the called one */ return; /* external invocation: return */ else { /* invocation via reentry: continue execution */ @@ -1051,7 +1143,7 @@ void luaV_execute (lua_State *L) { lua_Integer limit = ivalue(ra + 1); if ((0 < step) ? (idx <= limit) : (limit <= idx)) { ci->u.l.savedpc += GETARG_sBx(i); /* jump back */ - setivalue(ra, idx); /* update internal index... */ + chgivalue(ra, idx); /* update internal index... */ setivalue(ra + 3, idx); /* ...and external index */ } } @@ -1062,7 +1154,7 @@ void luaV_execute (lua_State *L) { if (luai_numlt(0, step) ? luai_numle(idx, limit) : luai_numle(limit, idx)) { ci->u.l.savedpc += GETARG_sBx(i); /* jump back */ - setfltvalue(ra, idx); /* update internal index... */ + chgfltvalue(ra, idx); /* update internal index... */ setfltvalue(ra + 3, idx); /* ...and external index */ } } |