xref: /illumos-gate/usr/src/uts/common/fs/zfs/lua/lcode.c (revision dfc115332c94a2f62058ac7f2bce7631fbd20b3d)
1 /*
2 ** $Id: lcode.c,v 2.62.1.1 2013/04/12 18:48:47 roberto Exp $
3 ** Code generator for Lua
4 ** See Copyright Notice in lua.h
5 */
6 
7 #include <sys/zfs_context.h>
8 
9 #define lcode_c
10 #define LUA_CORE
11 
12 #include "lua.h"
13 
14 #include "lcode.h"
15 #include "ldebug.h"
16 #include "ldo.h"
17 #include "lgc.h"
18 #include "llex.h"
19 #include "lmem.h"
20 #include "lobject.h"
21 #include "lopcodes.h"
22 #include "lparser.h"
23 #include "lstring.h"
24 #include "ltable.h"
25 #include "lvm.h"
26 
27 
28 #define hasjumps(e)	((e)->t != (e)->f)
29 
30 
isnumeral(expdesc * e)31 static int isnumeral(expdesc *e) {
32   return (e->k == VKNUM && e->t == NO_JUMP && e->f == NO_JUMP);
33 }
34 
35 
luaK_nil(FuncState * fs,int from,int n)36 void luaK_nil (FuncState *fs, int from, int n) {
37   Instruction *previous;
38   int l = from + n - 1;  /* last register to set nil */
39   if (fs->pc > fs->lasttarget) {  /* no jumps to current position? */
40     previous = &fs->f->code[fs->pc-1];
41     if (GET_OPCODE(*previous) == OP_LOADNIL) {
42       int pfrom = GETARG_A(*previous);
43       int pl = pfrom + GETARG_B(*previous);
44       if ((pfrom <= from && from <= pl + 1) ||
45           (from <= pfrom && pfrom <= l + 1)) {  /* can connect both? */
46         if (pfrom < from) from = pfrom;  /* from = min(from, pfrom) */
47         if (pl > l) l = pl;  /* l = max(l, pl) */
48         SETARG_A(*previous, from);
49         SETARG_B(*previous, l - from);
50         return;
51       }
52     }  /* else go through */
53   }
54   luaK_codeABC(fs, OP_LOADNIL, from, n - 1, 0);  /* else no optimization */
55 }
56 
57 
luaK_jump(FuncState * fs)58 int luaK_jump (FuncState *fs) {
59   int jpc = fs->jpc;  /* save list of jumps to here */
60   int j;
61   fs->jpc = NO_JUMP;
62   j = luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP);
63   luaK_concat(fs, &j, jpc);  /* keep them on hold */
64   return j;
65 }
66 
67 
luaK_ret(FuncState * fs,int first,int nret)68 void luaK_ret (FuncState *fs, int first, int nret) {
69   luaK_codeABC(fs, OP_RETURN, first, nret+1, 0);
70 }
71 
72 
condjump(FuncState * fs,OpCode op,int A,int B,int C)73 static int condjump (FuncState *fs, OpCode op, int A, int B, int C) {
74   luaK_codeABC(fs, op, A, B, C);
75   return luaK_jump(fs);
76 }
77 
78 
fixjump(FuncState * fs,int pc,int dest)79 static void fixjump (FuncState *fs, int pc, int dest) {
80   Instruction *jmp = &fs->f->code[pc];
81   int offset = dest-(pc+1);
82   lua_assert(dest != NO_JUMP);
83   if (abs(offset) > MAXARG_sBx)
84     luaX_syntaxerror(fs->ls, "control structure too long");
85   SETARG_sBx(*jmp, offset);
86 }
87 
88 
89 /*
90 ** returns current `pc' and marks it as a jump target (to avoid wrong
91 ** optimizations with consecutive instructions not in the same basic block).
92 */
luaK_getlabel(FuncState * fs)93 int luaK_getlabel (FuncState *fs) {
94   fs->lasttarget = fs->pc;
95   return fs->pc;
96 }
97 
98 
getjump(FuncState * fs,int pc)99 static int getjump (FuncState *fs, int pc) {
100   int offset = GETARG_sBx(fs->f->code[pc]);
101   if (offset == NO_JUMP)  /* point to itself represents end of list */
102     return NO_JUMP;  /* end of list */
103   else
104     return (pc+1)+offset;  /* turn offset into absolute position */
105 }
106 
107 
getjumpcontrol(FuncState * fs,int pc)108 static Instruction *getjumpcontrol (FuncState *fs, int pc) {
109   Instruction *pi = &fs->f->code[pc];
110   if (pc >= 1 && testTMode(GET_OPCODE(*(pi-1))))
111     return pi-1;
112   else
113     return pi;
114 }
115 
116 
117 /*
118 ** check whether list has any jump that do not produce a value
119 ** (or produce an inverted value)
120 */
need_value(FuncState * fs,int list)121 static int need_value (FuncState *fs, int list) {
122   for (; list != NO_JUMP; list = getjump(fs, list)) {
123     Instruction i = *getjumpcontrol(fs, list);
124     if (GET_OPCODE(i) != OP_TESTSET) return 1;
125   }
126   return 0;  /* not found */
127 }
128 
129 
patchtestreg(FuncState * fs,int node,int reg)130 static int patchtestreg (FuncState *fs, int node, int reg) {
131   Instruction *i = getjumpcontrol(fs, node);
132   if (GET_OPCODE(*i) != OP_TESTSET)
133     return 0;  /* cannot patch other instructions */
134   if (reg != NO_REG && reg != GETARG_B(*i))
135     SETARG_A(*i, reg);
136   else  /* no register to put value or register already has the value */
137     *i = CREATE_ABC(OP_TEST, GETARG_B(*i), 0, GETARG_C(*i));
138 
139   return 1;
140 }
141 
142 
removevalues(FuncState * fs,int list)143 static void removevalues (FuncState *fs, int list) {
144   for (; list != NO_JUMP; list = getjump(fs, list))
145       patchtestreg(fs, list, NO_REG);
146 }
147 
148 
patchlistaux(FuncState * fs,int list,int vtarget,int reg,int dtarget)149 static void patchlistaux (FuncState *fs, int list, int vtarget, int reg,
150                           int dtarget) {
151   while (list != NO_JUMP) {
152     int next = getjump(fs, list);
153     if (patchtestreg(fs, list, reg))
154       fixjump(fs, list, vtarget);
155     else
156       fixjump(fs, list, dtarget);  /* jump to default target */
157     list = next;
158   }
159 }
160 
161 
dischargejpc(FuncState * fs)162 static void dischargejpc (FuncState *fs) {
163   patchlistaux(fs, fs->jpc, fs->pc, NO_REG, fs->pc);
164   fs->jpc = NO_JUMP;
165 }
166 
167 
luaK_patchlist(FuncState * fs,int list,int target)168 void luaK_patchlist (FuncState *fs, int list, int target) {
169   if (target == fs->pc)
170     luaK_patchtohere(fs, list);
171   else {
172     lua_assert(target < fs->pc);
173     patchlistaux(fs, list, target, NO_REG, target);
174   }
175 }
176 
177 
luaK_patchclose(FuncState * fs,int list,int level)178 LUAI_FUNC void luaK_patchclose (FuncState *fs, int list, int level) {
179   level++;  /* argument is +1 to reserve 0 as non-op */
180   while (list != NO_JUMP) {
181     int next = getjump(fs, list);
182     lua_assert(GET_OPCODE(fs->f->code[list]) == OP_JMP &&
183                 (GETARG_A(fs->f->code[list]) == 0 ||
184                  GETARG_A(fs->f->code[list]) >= level));
185     SETARG_A(fs->f->code[list], level);
186     list = next;
187   }
188 }
189 
190 
luaK_patchtohere(FuncState * fs,int list)191 void luaK_patchtohere (FuncState *fs, int list) {
192   luaK_getlabel(fs);
193   luaK_concat(fs, &fs->jpc, list);
194 }
195 
196 
luaK_concat(FuncState * fs,int * l1,int l2)197 void luaK_concat (FuncState *fs, int *l1, int l2) {
198   if (l2 == NO_JUMP) return;
199   else if (*l1 == NO_JUMP)
200     *l1 = l2;
201   else {
202     int list = *l1;
203     int next;
204     while ((next = getjump(fs, list)) != NO_JUMP)  /* find last element */
205       list = next;
206     fixjump(fs, list, l2);
207   }
208 }
209 
210 
luaK_code(FuncState * fs,Instruction i)211 static int luaK_code (FuncState *fs, Instruction i) {
212   Proto *f = fs->f;
213   dischargejpc(fs);  /* `pc' will change */
214   /* put new instruction in code array */
215   luaM_growvector(fs->ls->L, f->code, fs->pc, f->sizecode, Instruction,
216                   MAX_INT, "opcodes");
217   f->code[fs->pc] = i;
218   /* save corresponding line information */
219   luaM_growvector(fs->ls->L, f->lineinfo, fs->pc, f->sizelineinfo, int,
220                   MAX_INT, "opcodes");
221   f->lineinfo[fs->pc] = fs->ls->lastline;
222   return fs->pc++;
223 }
224 
225 
luaK_codeABC(FuncState * fs,OpCode o,int a,int b,int c)226 int luaK_codeABC (FuncState *fs, OpCode o, int a, int b, int c) {
227   lua_assert(getOpMode(o) == iABC);
228   lua_assert(getBMode(o) != OpArgN || b == 0);
229   lua_assert(getCMode(o) != OpArgN || c == 0);
230   lua_assert(a <= MAXARG_A && b <= MAXARG_B && c <= MAXARG_C);
231   return luaK_code(fs, CREATE_ABC(o, a, b, c));
232 }
233 
234 
luaK_codeABx(FuncState * fs,OpCode o,int a,unsigned int bc)235 int luaK_codeABx (FuncState *fs, OpCode o, int a, unsigned int bc) {
236   lua_assert(getOpMode(o) == iABx || getOpMode(o) == iAsBx);
237   lua_assert(getCMode(o) == OpArgN);
238   lua_assert(a <= MAXARG_A && bc <= MAXARG_Bx);
239   return luaK_code(fs, CREATE_ABx(o, a, bc));
240 }
241 
242 
codeextraarg(FuncState * fs,int a)243 static int codeextraarg (FuncState *fs, int a) {
244   lua_assert(a <= MAXARG_Ax);
245   return luaK_code(fs, CREATE_Ax(OP_EXTRAARG, a));
246 }
247 
248 
luaK_codek(FuncState * fs,int reg,int k)249 int luaK_codek (FuncState *fs, int reg, int k) {
250   if (k <= MAXARG_Bx)
251     return luaK_codeABx(fs, OP_LOADK, reg, k);
252   else {
253     int p = luaK_codeABx(fs, OP_LOADKX, reg, 0);
254     codeextraarg(fs, k);
255     return p;
256   }
257 }
258 
259 
luaK_checkstack(FuncState * fs,int n)260 void luaK_checkstack (FuncState *fs, int n) {
261   int newstack = fs->freereg + n;
262   if (newstack > fs->f->maxstacksize) {
263     if (newstack >= MAXSTACK)
264       luaX_syntaxerror(fs->ls, "function or expression too complex");
265     fs->f->maxstacksize = cast_byte(newstack);
266   }
267 }
268 
269 
luaK_reserveregs(FuncState * fs,int n)270 void luaK_reserveregs (FuncState *fs, int n) {
271   luaK_checkstack(fs, n);
272   fs->freereg += n;
273 }
274 
275 
freereg(FuncState * fs,int reg)276 static void freereg (FuncState *fs, int reg) {
277   if (!ISK(reg) && reg >= fs->nactvar) {
278     fs->freereg--;
279     lua_assert(reg == fs->freereg);
280   }
281 }
282 
283 
freeexp(FuncState * fs,expdesc * e)284 static void freeexp (FuncState *fs, expdesc *e) {
285   if (e->k == VNONRELOC)
286     freereg(fs, e->u.info);
287 }
288 
289 
addk(FuncState * fs,TValue * key,TValue * v)290 static int addk (FuncState *fs, TValue *key, TValue *v) {
291   lua_State *L = fs->ls->L;
292   TValue *idx = luaH_set(L, fs->h, key);
293   Proto *f = fs->f;
294   int k, oldsize;
295   if (ttisnumber(idx)) {
296     lua_Number n = nvalue(idx);
297     lua_number2int(k, n);
298     if (luaV_rawequalobj(&f->k[k], v))
299       return k;
300     /* else may be a collision (e.g., between 0.0 and "\0\0\0\0\0\0\0\0");
301        go through and create a new entry for this value */
302   }
303   /* constant not found; create a new entry */
304   oldsize = f->sizek;
305   k = fs->nk;
306   /* numerical value does not need GC barrier;
307      table has no metatable, so it does not need to invalidate cache */
308   setnvalue(idx, cast_num(k));
309   luaM_growvector(L, f->k, k, f->sizek, TValue, MAXARG_Ax, "constants");
310   while (oldsize < f->sizek) setnilvalue(&f->k[oldsize++]);
311   setobj(L, &f->k[k], v);
312   fs->nk++;
313   luaC_barrier(L, f, v);
314   return k;
315 }
316 
317 
luaK_stringK(FuncState * fs,TString * s)318 int luaK_stringK (FuncState *fs, TString *s) {
319   TValue o;
320   setsvalue(fs->ls->L, &o, s);
321   return addk(fs, &o, &o);
322 }
323 
324 
luaK_numberK(FuncState * fs,lua_Number r)325 int luaK_numberK (FuncState *fs, lua_Number r) {
326   int n;
327   lua_State *L = fs->ls->L;
328   TValue o;
329   setnvalue(&o, r);
330   if (r == 0 || luai_numisnan(NULL, r)) {  /* handle -0 and NaN */
331     /* use raw representation as key to avoid numeric problems */
332     setsvalue(L, L->top++, luaS_newlstr(L, (char *)&r, sizeof(r)));
333     n = addk(fs, L->top - 1, &o);
334     L->top--;
335   }
336   else
337     n = addk(fs, &o, &o);  /* regular case */
338   return n;
339 }
340 
341 
boolK(FuncState * fs,int b)342 static int boolK (FuncState *fs, int b) {
343   TValue o;
344   setbvalue(&o, b);
345   return addk(fs, &o, &o);
346 }
347 
348 
nilK(FuncState * fs)349 static int nilK (FuncState *fs) {
350   TValue k, v;
351   setnilvalue(&v);
352   /* cannot use nil as key; instead use table itself to represent nil */
353   sethvalue(fs->ls->L, &k, fs->h);
354   return addk(fs, &k, &v);
355 }
356 
357 
luaK_setreturns(FuncState * fs,expdesc * e,int nresults)358 void luaK_setreturns (FuncState *fs, expdesc *e, int nresults) {
359   if (e->k == VCALL) {  /* expression is an open function call? */
360     SETARG_C(getcode(fs, e), nresults+1);
361   }
362   else if (e->k == VVARARG) {
363     SETARG_B(getcode(fs, e), nresults+1);
364     SETARG_A(getcode(fs, e), fs->freereg);
365     luaK_reserveregs(fs, 1);
366   }
367 }
368 
369 
luaK_setoneret(FuncState * fs,expdesc * e)370 void luaK_setoneret (FuncState *fs, expdesc *e) {
371   if (e->k == VCALL) {  /* expression is an open function call? */
372     e->k = VNONRELOC;
373     e->u.info = GETARG_A(getcode(fs, e));
374   }
375   else if (e->k == VVARARG) {
376     SETARG_B(getcode(fs, e), 2);
377     e->k = VRELOCABLE;  /* can relocate its simple result */
378   }
379 }
380 
381 
luaK_dischargevars(FuncState * fs,expdesc * e)382 void luaK_dischargevars (FuncState *fs, expdesc *e) {
383   switch (e->k) {
384     case VLOCAL: {
385       e->k = VNONRELOC;
386       break;
387     }
388     case VUPVAL: {
389       e->u.info = luaK_codeABC(fs, OP_GETUPVAL, 0, e->u.info, 0);
390       e->k = VRELOCABLE;
391       break;
392     }
393     case VINDEXED: {
394       OpCode op = OP_GETTABUP;  /* assume 't' is in an upvalue */
395       freereg(fs, e->u.ind.idx);
396       if (e->u.ind.vt == VLOCAL) {  /* 't' is in a register? */
397         freereg(fs, e->u.ind.t);
398         op = OP_GETTABLE;
399       }
400       e->u.info = luaK_codeABC(fs, op, 0, e->u.ind.t, e->u.ind.idx);
401       e->k = VRELOCABLE;
402       break;
403     }
404     case VVARARG:
405     case VCALL: {
406       luaK_setoneret(fs, e);
407       break;
408     }
409     default: break;  /* there is one value available (somewhere) */
410   }
411 }
412 
413 
code_label(FuncState * fs,int A,int b,int jump)414 static int code_label (FuncState *fs, int A, int b, int jump) {
415   luaK_getlabel(fs);  /* those instructions may be jump targets */
416   return luaK_codeABC(fs, OP_LOADBOOL, A, b, jump);
417 }
418 
419 
discharge2reg(FuncState * fs,expdesc * e,int reg)420 static void discharge2reg (FuncState *fs, expdesc *e, int reg) {
421   luaK_dischargevars(fs, e);
422   switch (e->k) {
423     case VNIL: {
424       luaK_nil(fs, reg, 1);
425       break;
426     }
427     case VFALSE: case VTRUE: {
428       luaK_codeABC(fs, OP_LOADBOOL, reg, e->k == VTRUE, 0);
429       break;
430     }
431     case VK: {
432       luaK_codek(fs, reg, e->u.info);
433       break;
434     }
435     case VKNUM: {
436       luaK_codek(fs, reg, luaK_numberK(fs, e->u.nval));
437       break;
438     }
439     case VRELOCABLE: {
440       Instruction *pc = &getcode(fs, e);
441       SETARG_A(*pc, reg);
442       break;
443     }
444     case VNONRELOC: {
445       if (reg != e->u.info)
446         luaK_codeABC(fs, OP_MOVE, reg, e->u.info, 0);
447       break;
448     }
449     default: {
450       lua_assert(e->k == VVOID || e->k == VJMP);
451       return;  /* nothing to do... */
452     }
453   }
454   e->u.info = reg;
455   e->k = VNONRELOC;
456 }
457 
458 
discharge2anyreg(FuncState * fs,expdesc * e)459 static void discharge2anyreg (FuncState *fs, expdesc *e) {
460   if (e->k != VNONRELOC) {
461     luaK_reserveregs(fs, 1);
462     discharge2reg(fs, e, fs->freereg-1);
463   }
464 }
465 
466 
exp2reg(FuncState * fs,expdesc * e,int reg)467 static void exp2reg (FuncState *fs, expdesc *e, int reg) {
468   discharge2reg(fs, e, reg);
469   if (e->k == VJMP)
470     luaK_concat(fs, &e->t, e->u.info);  /* put this jump in `t' list */
471   if (hasjumps(e)) {
472     int final;  /* position after whole expression */
473     int p_f = NO_JUMP;  /* position of an eventual LOAD false */
474     int p_t = NO_JUMP;  /* position of an eventual LOAD true */
475     if (need_value(fs, e->t) || need_value(fs, e->f)) {
476       int fj = (e->k == VJMP) ? NO_JUMP : luaK_jump(fs);
477       p_f = code_label(fs, reg, 0, 1);
478       p_t = code_label(fs, reg, 1, 0);
479       luaK_patchtohere(fs, fj);
480     }
481     final = luaK_getlabel(fs);
482     patchlistaux(fs, e->f, final, reg, p_f);
483     patchlistaux(fs, e->t, final, reg, p_t);
484   }
485   e->f = e->t = NO_JUMP;
486   e->u.info = reg;
487   e->k = VNONRELOC;
488 }
489 
490 
luaK_exp2nextreg(FuncState * fs,expdesc * e)491 void luaK_exp2nextreg (FuncState *fs, expdesc *e) {
492   luaK_dischargevars(fs, e);
493   freeexp(fs, e);
494   luaK_reserveregs(fs, 1);
495   exp2reg(fs, e, fs->freereg - 1);
496 }
497 
498 
luaK_exp2anyreg(FuncState * fs,expdesc * e)499 int luaK_exp2anyreg (FuncState *fs, expdesc *e) {
500   luaK_dischargevars(fs, e);
501   if (e->k == VNONRELOC) {
502     if (!hasjumps(e)) return e->u.info;  /* exp is already in a register */
503     if (e->u.info >= fs->nactvar) {  /* reg. is not a local? */
504       exp2reg(fs, e, e->u.info);  /* put value on it */
505       return e->u.info;
506     }
507   }
508   luaK_exp2nextreg(fs, e);  /* default */
509   return e->u.info;
510 }
511 
512 
luaK_exp2anyregup(FuncState * fs,expdesc * e)513 void luaK_exp2anyregup (FuncState *fs, expdesc *e) {
514   if (e->k != VUPVAL || hasjumps(e))
515     luaK_exp2anyreg(fs, e);
516 }
517 
518 
luaK_exp2val(FuncState * fs,expdesc * e)519 void luaK_exp2val (FuncState *fs, expdesc *e) {
520   if (hasjumps(e))
521     luaK_exp2anyreg(fs, e);
522   else
523     luaK_dischargevars(fs, e);
524 }
525 
526 
luaK_exp2RK(FuncState * fs,expdesc * e)527 int luaK_exp2RK (FuncState *fs, expdesc *e) {
528   luaK_exp2val(fs, e);
529   switch (e->k) {
530     case VTRUE:
531     case VFALSE:
532     case VNIL: {
533       if (fs->nk <= MAXINDEXRK) {  /* constant fits in RK operand? */
534         e->u.info = (e->k == VNIL) ? nilK(fs) : boolK(fs, (e->k == VTRUE));
535         e->k = VK;
536         return RKASK(e->u.info);
537       }
538       else break;
539     }
540     case VKNUM: {
541       e->u.info = luaK_numberK(fs, e->u.nval);
542       e->k = VK;
543       /* go through */
544     }
545     case VK: {
546       if (e->u.info <= MAXINDEXRK)  /* constant fits in argC? */
547         return RKASK(e->u.info);
548       else break;
549     }
550     default: break;
551   }
552   /* not a constant in the right range: put it in a register */
553   return luaK_exp2anyreg(fs, e);
554 }
555 
556 
luaK_storevar(FuncState * fs,expdesc * var,expdesc * ex)557 void luaK_storevar (FuncState *fs, expdesc *var, expdesc *ex) {
558   switch (var->k) {
559     case VLOCAL: {
560       freeexp(fs, ex);
561       exp2reg(fs, ex, var->u.info);
562       return;
563     }
564     case VUPVAL: {
565       int e = luaK_exp2anyreg(fs, ex);
566       luaK_codeABC(fs, OP_SETUPVAL, e, var->u.info, 0);
567       break;
568     }
569     case VINDEXED: {
570       OpCode op = (var->u.ind.vt == VLOCAL) ? OP_SETTABLE : OP_SETTABUP;
571       int e = luaK_exp2RK(fs, ex);
572       luaK_codeABC(fs, op, var->u.ind.t, var->u.ind.idx, e);
573       break;
574     }
575     default: {
576       lua_assert(0);  /* invalid var kind to store */
577       break;
578     }
579   }
580   freeexp(fs, ex);
581 }
582 
583 
luaK_self(FuncState * fs,expdesc * e,expdesc * key)584 void luaK_self (FuncState *fs, expdesc *e, expdesc *key) {
585   int ereg;
586   luaK_exp2anyreg(fs, e);
587   ereg = e->u.info;  /* register where 'e' was placed */
588   freeexp(fs, e);
589   e->u.info = fs->freereg;  /* base register for op_self */
590   e->k = VNONRELOC;
591   luaK_reserveregs(fs, 2);  /* function and 'self' produced by op_self */
592   luaK_codeABC(fs, OP_SELF, e->u.info, ereg, luaK_exp2RK(fs, key));
593   freeexp(fs, key);
594 }
595 
596 
invertjump(FuncState * fs,expdesc * e)597 static void invertjump (FuncState *fs, expdesc *e) {
598   Instruction *pc = getjumpcontrol(fs, e->u.info);
599   lua_assert(testTMode(GET_OPCODE(*pc)) && GET_OPCODE(*pc) != OP_TESTSET &&
600                                            GET_OPCODE(*pc) != OP_TEST);
601   SETARG_A(*pc, !(GETARG_A(*pc)));
602 }
603 
604 
jumponcond(FuncState * fs,expdesc * e,int cond)605 static int jumponcond (FuncState *fs, expdesc *e, int cond) {
606   if (e->k == VRELOCABLE) {
607     Instruction ie = getcode(fs, e);
608     if (GET_OPCODE(ie) == OP_NOT) {
609       fs->pc--;  /* remove previous OP_NOT */
610       return condjump(fs, OP_TEST, GETARG_B(ie), 0, !cond);
611     }
612     /* else go through */
613   }
614   discharge2anyreg(fs, e);
615   freeexp(fs, e);
616   return condjump(fs, OP_TESTSET, NO_REG, e->u.info, cond);
617 }
618 
619 
luaK_goiftrue(FuncState * fs,expdesc * e)620 void luaK_goiftrue (FuncState *fs, expdesc *e) {
621   int pc;  /* pc of last jump */
622   luaK_dischargevars(fs, e);
623   switch (e->k) {
624     case VJMP: {
625       invertjump(fs, e);
626       pc = e->u.info;
627       break;
628     }
629     case VK: case VKNUM: case VTRUE: {
630       pc = NO_JUMP;  /* always true; do nothing */
631       break;
632     }
633     default: {
634       pc = jumponcond(fs, e, 0);
635       break;
636     }
637   }
638   luaK_concat(fs, &e->f, pc);  /* insert last jump in `f' list */
639   luaK_patchtohere(fs, e->t);
640   e->t = NO_JUMP;
641 }
642 
643 
luaK_goiffalse(FuncState * fs,expdesc * e)644 void luaK_goiffalse (FuncState *fs, expdesc *e) {
645   int pc;  /* pc of last jump */
646   luaK_dischargevars(fs, e);
647   switch (e->k) {
648     case VJMP: {
649       pc = e->u.info;
650       break;
651     }
652     case VNIL: case VFALSE: {
653       pc = NO_JUMP;  /* always false; do nothing */
654       break;
655     }
656     default: {
657       pc = jumponcond(fs, e, 1);
658       break;
659     }
660   }
661   luaK_concat(fs, &e->t, pc);  /* insert last jump in `t' list */
662   luaK_patchtohere(fs, e->f);
663   e->f = NO_JUMP;
664 }
665 
666 
codenot(FuncState * fs,expdesc * e)667 static void codenot (FuncState *fs, expdesc *e) {
668   luaK_dischargevars(fs, e);
669   switch (e->k) {
670     case VNIL: case VFALSE: {
671       e->k = VTRUE;
672       break;
673     }
674     case VK: case VKNUM: case VTRUE: {
675       e->k = VFALSE;
676       break;
677     }
678     case VJMP: {
679       invertjump(fs, e);
680       break;
681     }
682     case VRELOCABLE:
683     case VNONRELOC: {
684       discharge2anyreg(fs, e);
685       freeexp(fs, e);
686       e->u.info = luaK_codeABC(fs, OP_NOT, 0, e->u.info, 0);
687       e->k = VRELOCABLE;
688       break;
689     }
690     default: {
691       lua_assert(0);  /* cannot happen */
692       break;
693     }
694   }
695   /* interchange true and false lists */
696   { int temp = e->f; e->f = e->t; e->t = temp; }
697   removevalues(fs, e->f);
698   removevalues(fs, e->t);
699 }
700 
701 
luaK_indexed(FuncState * fs,expdesc * t,expdesc * k)702 void luaK_indexed (FuncState *fs, expdesc *t, expdesc *k) {
703   lua_assert(!hasjumps(t));
704   t->u.ind.t = t->u.info;
705   t->u.ind.idx = luaK_exp2RK(fs, k);
706   t->u.ind.vt = (t->k == VUPVAL) ? VUPVAL
707                                  : check_exp(vkisinreg(t->k), VLOCAL);
708   t->k = VINDEXED;
709 }
710 
711 
constfolding(OpCode op,expdesc * e1,expdesc * e2)712 static int constfolding (OpCode op, expdesc *e1, expdesc *e2) {
713   lua_Number r;
714   if (!isnumeral(e1) || !isnumeral(e2)) return 0;
715   if ((op == OP_DIV || op == OP_MOD) && e2->u.nval == 0)
716     return 0;  /* do not attempt to divide by 0 */
717   /*
718    * Patched: check for MIN_INT / -1
719    */
720   if (op == OP_DIV && e1->u.nval == INT64_MIN && e2->u.nval == -1)
721     return 0;
722   r = luaO_arith(op - OP_ADD + LUA_OPADD, e1->u.nval, e2->u.nval);
723   e1->u.nval = r;
724   return 1;
725 }
726 
727 
codearith(FuncState * fs,OpCode op,expdesc * e1,expdesc * e2,int line)728 static void codearith (FuncState *fs, OpCode op,
729                        expdesc *e1, expdesc *e2, int line) {
730   if (constfolding(op, e1, e2))
731     return;
732   else {
733     int o2 = (op != OP_UNM && op != OP_LEN) ? luaK_exp2RK(fs, e2) : 0;
734     int o1 = luaK_exp2RK(fs, e1);
735     if (o1 > o2) {
736       freeexp(fs, e1);
737       freeexp(fs, e2);
738     }
739     else {
740       freeexp(fs, e2);
741       freeexp(fs, e1);
742     }
743     e1->u.info = luaK_codeABC(fs, op, 0, o1, o2);
744     e1->k = VRELOCABLE;
745     luaK_fixline(fs, line);
746   }
747 }
748 
749 
codecomp(FuncState * fs,OpCode op,int cond,expdesc * e1,expdesc * e2)750 static void codecomp (FuncState *fs, OpCode op, int cond, expdesc *e1,
751                                                           expdesc *e2) {
752   int o1 = luaK_exp2RK(fs, e1);
753   int o2 = luaK_exp2RK(fs, e2);
754   freeexp(fs, e2);
755   freeexp(fs, e1);
756   if (cond == 0 && op != OP_EQ) {
757     int temp;  /* exchange args to replace by `<' or `<=' */
758     temp = o1; o1 = o2; o2 = temp;  /* o1 <==> o2 */
759     cond = 1;
760   }
761   e1->u.info = condjump(fs, op, cond, o1, o2);
762   e1->k = VJMP;
763 }
764 
765 
luaK_prefix(FuncState * fs,UnOpr op,expdesc * e,int line)766 void luaK_prefix (FuncState *fs, UnOpr op, expdesc *e, int line) {
767   expdesc e2;
768   e2.t = e2.f = NO_JUMP; e2.k = VKNUM; e2.u.nval = 0;
769   switch (op) {
770     case OPR_MINUS: {
771       if (isnumeral(e))  /* minus constant? */
772         e->u.nval = luai_numunm(NULL, e->u.nval);  /* fold it */
773       else {
774         luaK_exp2anyreg(fs, e);
775         codearith(fs, OP_UNM, e, &e2, line);
776       }
777       break;
778     }
779     case OPR_NOT: codenot(fs, e); break;
780     case OPR_LEN: {
781       luaK_exp2anyreg(fs, e);  /* cannot operate on constants */
782       codearith(fs, OP_LEN, e, &e2, line);
783       break;
784     }
785     default: lua_assert(0);
786   }
787 }
788 
789 
luaK_infix(FuncState * fs,BinOpr op,expdesc * v)790 void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) {
791   switch (op) {
792     case OPR_AND: {
793       luaK_goiftrue(fs, v);
794       break;
795     }
796     case OPR_OR: {
797       luaK_goiffalse(fs, v);
798       break;
799     }
800     case OPR_CONCAT: {
801       luaK_exp2nextreg(fs, v);  /* operand must be on the `stack' */
802       break;
803     }
804     case OPR_ADD: case OPR_SUB: case OPR_MUL: case OPR_DIV:
805     case OPR_MOD: case OPR_POW: {
806       if (!isnumeral(v)) luaK_exp2RK(fs, v);
807       break;
808     }
809     default: {
810       luaK_exp2RK(fs, v);
811       break;
812     }
813   }
814 }
815 
816 
luaK_posfix(FuncState * fs,BinOpr op,expdesc * e1,expdesc * e2,int line)817 void luaK_posfix (FuncState *fs, BinOpr op,
818                   expdesc *e1, expdesc *e2, int line) {
819   switch (op) {
820     case OPR_AND: {
821       lua_assert(e1->t == NO_JUMP);  /* list must be closed */
822       luaK_dischargevars(fs, e2);
823       luaK_concat(fs, &e2->f, e1->f);
824       *e1 = *e2;
825       break;
826     }
827     case OPR_OR: {
828       lua_assert(e1->f == NO_JUMP);  /* list must be closed */
829       luaK_dischargevars(fs, e2);
830       luaK_concat(fs, &e2->t, e1->t);
831       *e1 = *e2;
832       break;
833     }
834     case OPR_CONCAT: {
835       luaK_exp2val(fs, e2);
836       if (e2->k == VRELOCABLE && GET_OPCODE(getcode(fs, e2)) == OP_CONCAT) {
837         lua_assert(e1->u.info == GETARG_B(getcode(fs, e2))-1);
838         freeexp(fs, e1);
839         SETARG_B(getcode(fs, e2), e1->u.info);
840         e1->k = VRELOCABLE; e1->u.info = e2->u.info;
841       }
842       else {
843         luaK_exp2nextreg(fs, e2);  /* operand must be on the 'stack' */
844         codearith(fs, OP_CONCAT, e1, e2, line);
845       }
846       break;
847     }
848     case OPR_ADD: case OPR_SUB: case OPR_MUL: case OPR_DIV:
849     case OPR_MOD: case OPR_POW: {
850       codearith(fs, cast(OpCode, op - OPR_ADD + OP_ADD), e1, e2, line);
851       break;
852     }
853     case OPR_EQ: case OPR_LT: case OPR_LE: {
854       codecomp(fs, cast(OpCode, op - OPR_EQ + OP_EQ), 1, e1, e2);
855       break;
856     }
857     case OPR_NE: case OPR_GT: case OPR_GE: {
858       codecomp(fs, cast(OpCode, op - OPR_NE + OP_EQ), 0, e1, e2);
859       break;
860     }
861     default: lua_assert(0);
862   }
863 }
864 
865 
luaK_fixline(FuncState * fs,int line)866 void luaK_fixline (FuncState *fs, int line) {
867   fs->f->lineinfo[fs->pc - 1] = line;
868 }
869 
870 
luaK_setlist(FuncState * fs,int base,int nelems,int tostore)871 void luaK_setlist (FuncState *fs, int base, int nelems, int tostore) {
872   int c =  (nelems - 1)/LFIELDS_PER_FLUSH + 1;
873   int b = (tostore == LUA_MULTRET) ? 0 : tostore;
874   lua_assert(tostore != 0);
875   if (c <= MAXARG_C)
876     luaK_codeABC(fs, OP_SETLIST, base, b, c);
877   else if (c <= MAXARG_Ax) {
878     luaK_codeABC(fs, OP_SETLIST, base, b, 0);
879     codeextraarg(fs, c);
880   }
881   else
882     luaX_syntaxerror(fs->ls, "constructor too long");
883   fs->freereg = base + 1;  /* free registers with list values */
884 }
885 
886