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jumps in 'for' loops don't need to be signed

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This commit is contained in:
Roberto Ierusalimschy 2017-08-14 15:33:14 -03:00
parent f185c0132e
commit ac65bab25f
4 changed files with 38 additions and 20 deletions
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8
lopcodes.c
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@ -1,5 +1,5 @@
/* /*
** $Id: lopcodes.c,v 1.58 2017/04/28 20:57:45 roberto Exp roberto $ ** $Id: lopcodes.c,v 1.59 2017/06/29 15:38:41 roberto Exp roberto $
** Opcodes for Lua virtual machine ** Opcodes for Lua virtual machine
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@ -124,10 +124,10 @@ LUAI_DDEF const lu_byte luaP_opmodes[NUM_OPCODES] = {
,opmode(0, 1, OpArgU, OpArgU, iABC) /* OP_CALL */ ,opmode(0, 1, OpArgU, OpArgU, iABC) /* OP_CALL */
,opmode(0, 1, OpArgU, OpArgU, iABC) /* OP_TAILCALL */ ,opmode(0, 1, OpArgU, OpArgU, iABC) /* OP_TAILCALL */
,opmode(0, 0, OpArgU, OpArgN, iABC) /* OP_RETURN */ ,opmode(0, 0, OpArgU, OpArgN, iABC) /* OP_RETURN */
,opmode(0, 1, OpArgR, OpArgN, iAsBx) /* OP_FORLOOP */ ,opmode(0, 1, OpArgR, OpArgN, iABx) /* OP_FORLOOP */
,opmode(0, 1, OpArgR, OpArgN, iAsBx) /* OP_FORPREP */ ,opmode(0, 1, OpArgR, OpArgN, iABx) /* OP_FORPREP */
,opmode(0, 0, OpArgN, OpArgU, iABC) /* OP_TFORCALL */ ,opmode(0, 0, OpArgN, OpArgU, iABC) /* OP_TFORCALL */
,opmode(0, 1, OpArgR, OpArgN, iAsBx) /* OP_TFORLOOP */ ,opmode(0, 1, OpArgR, OpArgN, iABx) /* OP_TFORLOOP */
,opmode(0, 0, OpArgU, OpArgU, iABC) /* OP_SETLIST */ ,opmode(0, 0, OpArgU, OpArgU, iABC) /* OP_SETLIST */
,opmode(0, 1, OpArgU, OpArgN, iABx) /* OP_CLOSURE */ ,opmode(0, 1, OpArgU, OpArgN, iABx) /* OP_CLOSURE */
,opmode(0, 1, OpArgU, OpArgR, iABC) /* OP_VARARG */ ,opmode(0, 1, OpArgU, OpArgR, iABC) /* OP_VARARG */

10
lopcodes.h
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@ -1,5 +1,5 @@
/* /*
** $Id: lopcodes.h,v 1.154 2017/05/08 16:08:01 roberto Exp roberto $ ** $Id: lopcodes.h,v 1.155 2017/06/29 15:38:41 roberto Exp roberto $
** Opcodes for Lua virtual machine ** Opcodes for Lua virtual machine
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@ -229,12 +229,12 @@ OP_CALL,/* A B C R(A), ... ,R(A+C-2) := R(A)(R(A+1), ... ,R(A+B-1)) */
OP_TAILCALL,/* A B C return R(A)(R(A+1), ... ,R(A+B-1)) */ OP_TAILCALL,/* A B C return R(A)(R(A+1), ... ,R(A+B-1)) */
OP_RETURN,/* A B return R(A), ... ,R(A+B-2) (see note) */ OP_RETURN,/* A B return R(A), ... ,R(A+B-2) (see note) */
OP_FORLOOP,/* A sBx R(A)+=R(A+2); OP_FORLOOP,/* A Bx R(A)+=R(A+2);
if R(A) <?= R(A+1) then { pc+=sBx; R(A+3)=R(A) }*/ if R(A) <?= R(A+1) then { pc-=Bx; R(A+3)=R(A) }*/
OP_FORPREP,/* A sBx R(A)-=R(A+2); pc+=sBx */ OP_FORPREP,/* A Bx R(A)-=R(A+2); pc+=Bx */
OP_TFORCALL,/* A C R(A+3), ... ,R(A+2+C) := R(A)(R(A+1), R(A+2)); */ OP_TFORCALL,/* A C R(A+3), ... ,R(A+2+C) := R(A)(R(A+1), R(A+2)); */
OP_TFORLOOP,/* A sBx if R(A+1) ~= nil then { R(A)=R(A+1); pc += sBx }*/ OP_TFORLOOP,/* A Bx if R(A+1) ~= nil then { R(A)=R(A+1); pc -= Bx }*/
OP_SETLIST,/* A B C R(A)[(C-1)*FPF+i] := R(A+i), 1 <= i <= B */ OP_SETLIST,/* A B C R(A)[(C-1)*FPF+i] := R(A+i), 1 <= i <= B */

30
lparser.c
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@ -1,5 +1,5 @@
/* /*
** $Id: lparser.c,v 2.162 2017/06/29 15:38:41 roberto Exp roberto $ ** $Id: lparser.c,v 2.163 2017/08/12 13:12:21 roberto Exp roberto $
** Lua Parser ** Lua Parser
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@ -1307,6 +1307,22 @@ static int exp1 (LexState *ls) {
} }
/*
** Fix for instruction at position 'pc' to jump to 'dest'.
** (Jump addresses are relative in Lua). 'back' true means
** a back jump.
*/
static void fixforjump (FuncState *fs, int pc, int dest, int back) {
Instruction *jmp = &fs->f->code[pc];
int offset = dest - (pc + 1);
if (back)
offset = -offset;
if (offset > MAXARG_Bx)
luaX_syntaxerror(fs->ls, "control structure too long");
SETARG_Bx(*jmp, offset);
}
static void forbody (LexState *ls, int base, int line, int nvars, int isnum) { static void forbody (LexState *ls, int base, int line, int nvars, int isnum) {
/* forbody -> DO block */ /* forbody -> DO block */
BlockCnt bl; BlockCnt bl;
@ -1314,21 +1330,23 @@ static void forbody (LexState *ls, int base, int line, int nvars, int isnum) {
int prep, endfor; int prep, endfor;
adjustlocalvars(ls, 3); /* control variables */ adjustlocalvars(ls, 3); /* control variables */
checknext(ls, TK_DO); checknext(ls, TK_DO);
prep = isnum ? luaK_codeAsBx(fs, OP_FORPREP, base, NO_JUMP) : luaK_jump(fs); prep = isnum ? luaK_codeABx(fs, OP_FORPREP, base, 0) : luaK_jump(fs);
enterblock(fs, &bl, 0); /* scope for declared variables */ enterblock(fs, &bl, 0); /* scope for declared variables */
adjustlocalvars(ls, nvars); adjustlocalvars(ls, nvars);
luaK_reserveregs(fs, nvars); luaK_reserveregs(fs, nvars);
block(ls); block(ls);
leaveblock(fs); /* end of scope for declared variables */ leaveblock(fs); /* end of scope for declared variables */
luaK_patchtohere(fs, prep); if (isnum) { /* numeric for? */
if (isnum) /* numeric for? */ fixforjump(fs, prep, luaK_getlabel(fs), 0);
endfor = luaK_codeAsBx(fs, OP_FORLOOP, base, NO_JUMP); endfor = luaK_codeABx(fs, OP_FORLOOP, base, 0);
}
else { /* generic for */ else { /* generic for */
luaK_patchtohere(fs, prep);
luaK_codeABC(fs, OP_TFORCALL, base, 0, nvars); luaK_codeABC(fs, OP_TFORCALL, base, 0, nvars);
luaK_fixline(fs, line); luaK_fixline(fs, line);
endfor = luaK_codeAsBx(fs, OP_TFORLOOP, base + 2, NO_JUMP); endfor = luaK_codeAsBx(fs, OP_TFORLOOP, base + 2, NO_JUMP);
} }
luaK_patchlist(fs, endfor, prep + 1); fixforjump(fs, endfor, prep + 1, 1);
luaK_fixline(fs, line); luaK_fixline(fs, line);
} }

10
lvm.c
View File

@ -1,5 +1,5 @@
/* /*
** $Id: lvm.c,v 2.289 2017/06/29 15:38:41 roberto Exp roberto $ ** $Id: lvm.c,v 2.290 2017/07/07 16:34:32 roberto Exp roberto $
** Lua virtual machine ** Lua virtual machine
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@ -1335,7 +1335,7 @@ void luaV_execute (lua_State *L) {
lua_Integer idx = intop(+, ivalue(s2v(ra)), step); /* increment index */ lua_Integer idx = intop(+, ivalue(s2v(ra)), step); /* increment index */
lua_Integer limit = ivalue(s2v(ra + 1)); lua_Integer limit = ivalue(s2v(ra + 1));
if ((0 < step) ? (idx <= limit) : (limit <= idx)) { if ((0 < step) ? (idx <= limit) : (limit <= idx)) {
pc += GETARG_sBx(i); /* jump back */ pc -= GETARG_Bx(i); /* jump back */
chgivalue(s2v(ra), idx); /* update internal index... */ chgivalue(s2v(ra), idx); /* update internal index... */
setivalue(s2v(ra + 3), idx); /* ...and external index */ setivalue(s2v(ra + 3), idx); /* ...and external index */
} }
@ -1347,7 +1347,7 @@ void luaV_execute (lua_State *L) {
idx = luai_numadd(L, idx, step); /* inc. index */ idx = luai_numadd(L, idx, step); /* inc. index */
if (luai_numlt(0, step) ? luai_numle(idx, limit) if (luai_numlt(0, step) ? luai_numle(idx, limit)
: luai_numle(limit, idx)) { : luai_numle(limit, idx)) {
pc += GETARG_sBx(i); /* jump back */ pc -= GETARG_Bx(i); /* jump back */
chgfltvalue(s2v(ra), idx); /* update internal index... */ chgfltvalue(s2v(ra), idx); /* update internal index... */
setfltvalue(s2v(ra + 3), idx); /* ...and external index */ setfltvalue(s2v(ra + 3), idx); /* ...and external index */
} }
@ -1381,7 +1381,7 @@ void luaV_execute (lua_State *L) {
luaG_runerror(L, "'for' initial value must be a number"); luaG_runerror(L, "'for' initial value must be a number");
setfltvalue(init, luai_numsub(L, ninit, nstep)); setfltvalue(init, luai_numsub(L, ninit, nstep));
} }
pc += GETARG_sBx(i); pc += GETARG_Bx(i);
vmbreak; vmbreak;
} }
vmcase(OP_TFORCALL) { vmcase(OP_TFORCALL) {
@ -1401,7 +1401,7 @@ void luaV_execute (lua_State *L) {
l_tforloop: l_tforloop:
if (!ttisnil(s2v(ra + 1))) { /* continue loop? */ if (!ttisnil(s2v(ra + 1))) { /* continue loop? */
setobjs2s(L, ra, ra + 1); /* save control variable */ setobjs2s(L, ra, ra + 1); /* save control variable */
pc += GETARG_sBx(i); /* jump back */ pc -= GETARG_Bx(i); /* jump back */
} }
vmbreak; vmbreak;
} }