1/*
2** $Id: lcode.c $
3** Code generator for Lua
4** See Copyright Notice in lua.h
5*/
6
7#define lcode_c
8#define LUA_CORE
9
10#include "lprefix.h"
11
12
13#include <float.h>
14#include <limits.h>
15#include <math.h>
16#include <stdlib.h>
17
18#include "lua.h"
19
20#include "lcode.h"
21#include "ldebug.h"
22#include "ldo.h"
23#include "lgc.h"
24#include "llex.h"
25#include "lmem.h"
26#include "lobject.h"
27#include "lopcodes.h"
28#include "lparser.h"
29#include "lstring.h"
30#include "ltable.h"
31#include "lvm.h"
32
33
34/* Maximum number of registers in a Lua function (must fit in 8 bits) */
35#define MAXREGS 255
36
37
38/* (note that expressions VJMP also have jumps.) */
39#define hasjumps(e) ((e)->t != (e)->f)
40
41
42static int codesJ (FuncState *fs, OpCode o, int sj, int k);
43
44
45
46/* semantic error */
47l_noret luaK_semerror (LexState *ls, const char *msg) {
48 ls->t.token = 0; /* remove "near <token>" from final message */
49 luaX_syntaxerror(ls, msg);
50}
51
52
53/*
54** If expression is a numeric constant, fills 'v' with its value
55** and returns 1. Otherwise, returns 0.
56*/
57static int tonumeral (const expdesc *e, TValue *v) {
58 if (hasjumps(e))
59 return 0; /* not a numeral */
60 switch (e->k) {
61 case VKINT:
62 if (v) setivalue(v, e->u.ival);
63 return 1;
64 case VKFLT:
65 if (v) setfltvalue(v, e->u.nval);
66 return 1;
67 default: return 0;
68 }
69}
70
71
72/*
73** Get the constant value from a constant expression
74*/
75static TValue *const2val (FuncState *fs, const expdesc *e) {
76 lua_assert(e->k == VCONST);
77 return &fs->ls->dyd->actvar.arr[e->u.info].k;
78}
79
80
81/*
82** If expression is a constant, fills 'v' with its value
83** and returns 1. Otherwise, returns 0.
84*/
85int luaK_exp2const (FuncState *fs, const expdesc *e, TValue *v) {
86 if (hasjumps(e))
87 return 0; /* not a constant */
88 switch (e->k) {
89 case VFALSE:
90 setbfvalue(v);
91 return 1;
92 case VTRUE:
93 setbtvalue(v);
94 return 1;
95 case VNIL:
96 setnilvalue(v);
97 return 1;
98 case VKSTR: {
99 setsvalue(fs->ls->L, v, e->u.strval);
100 return 1;
101 }
102 case VCONST: {
103 setobj(fs->ls->L, v, const2val(fs, e));
104 return 1;
105 }
106 default: return tonumeral(e, v);
107 }
108}
109
110
111/*
112** Return the previous instruction of the current code. If there
113** may be a jump target between the current instruction and the
114** previous one, return an invalid instruction (to avoid wrong
115** optimizations).
116*/
117static Instruction *previousinstruction (FuncState *fs) {
118 static const Instruction invalidinstruction = ~(Instruction)0;
119 if (fs->pc > fs->lasttarget)
120 return &fs->f->code[fs->pc - 1]; /* previous instruction */
121 else
122 return cast(Instruction*, &invalidinstruction);
123}
124
125
126/*
127** Create a OP_LOADNIL instruction, but try to optimize: if the previous
128** instruction is also OP_LOADNIL and ranges are compatible, adjust
129** range of previous instruction instead of emitting a new one. (For
130** instance, 'local a; local b' will generate a single opcode.)
131*/
132void luaK_nil (FuncState *fs, int from, int n) {
133 int l = from + n - 1; /* last register to set nil */
134 Instruction *previous = previousinstruction(fs);
135 if (GET_OPCODE(*previous) == OP_LOADNIL) { /* previous is LOADNIL? */
136 int pfrom = GETARG_A(*previous); /* get previous range */
137 int pl = pfrom + GETARG_B(*previous);
138 if ((pfrom <= from && from <= pl + 1) ||
139 (from <= pfrom && pfrom <= l + 1)) { /* can connect both? */
140 if (pfrom < from) from = pfrom; /* from = min(from, pfrom) */
141 if (pl > l) l = pl; /* l = max(l, pl) */
142 SETARG_A(*previous, from);
143 SETARG_B(*previous, l - from);
144 return;
145 } /* else go through */
146 }
147 luaK_codeABC(fs, OP_LOADNIL, from, n - 1, 0); /* else no optimization */
148}
149
150
151/*
152** Gets the destination address of a jump instruction. Used to traverse
153** a list of jumps.
154*/
155static int getjump (FuncState *fs, int pc) {
156 int offset = GETARG_sJ(fs->f->code[pc]);
157 if (offset == NO_JUMP) /* point to itself represents end of list */
158 return NO_JUMP; /* end of list */
159 else
160 return (pc+1)+offset; /* turn offset into absolute position */
161}
162
163
164/*
165** Fix jump instruction at position 'pc' to jump to 'dest'.
166** (Jump addresses are relative in Lua)
167*/
168static void fixjump (FuncState *fs, int pc, int dest) {
169 Instruction *jmp = &fs->f->code[pc];
170 int offset = dest - (pc + 1);
171 lua_assert(dest != NO_JUMP);
172 if (!(-OFFSET_sJ <= offset && offset <= MAXARG_sJ - OFFSET_sJ))
173 luaX_syntaxerror(fs->ls, "control structure too long");
174 lua_assert(GET_OPCODE(*jmp) == OP_JMP);
175 SETARG_sJ(*jmp, offset);
176}
177
178
179/*
180** Concatenate jump-list 'l2' into jump-list 'l1'
181*/
182void luaK_concat (FuncState *fs, int *l1, int l2) {
183 if (l2 == NO_JUMP) return; /* nothing to concatenate? */
184 else if (*l1 == NO_JUMP) /* no original list? */
185 *l1 = l2; /* 'l1' points to 'l2' */
186 else {
187 int list = *l1;
188 int next;
189 while ((next = getjump(fs, list)) != NO_JUMP) /* find last element */
190 list = next;
191 fixjump(fs, list, l2); /* last element links to 'l2' */
192 }
193}
194
195
196/*
197** Create a jump instruction and return its position, so its destination
198** can be fixed later (with 'fixjump').
199*/
200int luaK_jump (FuncState *fs) {
201 return codesJ(fs, OP_JMP, NO_JUMP, 0);
202}
203
204
205/*
206** Code a 'return' instruction
207*/
208void luaK_ret (FuncState *fs, int first, int nret) {
209 OpCode op;
210 switch (nret) {
211 case 0: op = OP_RETURN0; break;
212 case 1: op = OP_RETURN1; break;
213 default: op = OP_RETURN; break;
214 }
215 luaK_codeABC(fs, op, first, nret + 1, 0);
216}
217
218
219/*
220** Code a "conditional jump", that is, a test or comparison opcode
221** followed by a jump. Return jump position.
222*/
223static int condjump (FuncState *fs, OpCode op, int A, int B, int C, int k) {
224 luaK_codeABCk(fs, op, A, B, C, k);
225 return luaK_jump(fs);
226}
227
228
229/*
230** returns current 'pc' and marks it as a jump target (to avoid wrong
231** optimizations with consecutive instructions not in the same basic block).
232*/
233int luaK_getlabel (FuncState *fs) {
234 fs->lasttarget = fs->pc;
235 return fs->pc;
236}
237
238
239/*
240** Returns the position of the instruction "controlling" a given
241** jump (that is, its condition), or the jump itself if it is
242** unconditional.
243*/
244static Instruction *getjumpcontrol (FuncState *fs, int pc) {
245 Instruction *pi = &fs->f->code[pc];
246 if (pc >= 1 && testTMode(GET_OPCODE(*(pi-1))))
247 return pi-1;
248 else
249 return pi;
250}
251
252
253/*
254** Patch destination register for a TESTSET instruction.
255** If instruction in position 'node' is not a TESTSET, return 0 ("fails").
256** Otherwise, if 'reg' is not 'NO_REG', set it as the destination
257** register. Otherwise, change instruction to a simple 'TEST' (produces
258** no register value)
259*/
260static int patchtestreg (FuncState *fs, int node, int reg) {
261 Instruction *i = getjumpcontrol(fs, node);
262 if (GET_OPCODE(*i) != OP_TESTSET)
263 return 0; /* cannot patch other instructions */
264 if (reg != NO_REG && reg != GETARG_B(*i))
265 SETARG_A(*i, reg);
266 else {
267 /* no register to put value or register already has the value;
268 change instruction to simple test */
269 *i = CREATE_ABCk(OP_TEST, GETARG_B(*i), 0, 0, GETARG_k(*i));
270 }
271 return 1;
272}
273
274
275/*
276** Traverse a list of tests ensuring no one produces a value
277*/
278static void removevalues (FuncState *fs, int list) {
279 for (; list != NO_JUMP; list = getjump(fs, list))
280 patchtestreg(fs, list, NO_REG);
281}
282
283
284/*
285** Traverse a list of tests, patching their destination address and
286** registers: tests producing values jump to 'vtarget' (and put their
287** values in 'reg'), other tests jump to 'dtarget'.
288*/
289static void patchlistaux (FuncState *fs, int list, int vtarget, int reg,
290 int dtarget) {
291 while (list != NO_JUMP) {
292 int next = getjump(fs, list);
293 if (patchtestreg(fs, list, reg))
294 fixjump(fs, list, vtarget);
295 else
296 fixjump(fs, list, dtarget); /* jump to default target */
297 list = next;
298 }
299}
300
301
302/*
303** Path all jumps in 'list' to jump to 'target'.
304** (The assert means that we cannot fix a jump to a forward address
305** because we only know addresses once code is generated.)
306*/
307void luaK_patchlist (FuncState *fs, int list, int target) {
308 lua_assert(target <= fs->pc);
309 patchlistaux(fs, list, target, NO_REG, target);
310}
311
312
313void luaK_patchtohere (FuncState *fs, int list) {
314 int hr = luaK_getlabel(fs); /* mark "here" as a jump target */
315 luaK_patchlist(fs, list, hr);
316}
317
318
319/* limit for difference between lines in relative line info. */
320#define LIMLINEDIFF 0x80
321
322
323/*
324** Save line info for a new instruction. If difference from last line
325** does not fit in a byte, of after that many instructions, save a new
326** absolute line info; (in that case, the special value 'ABSLINEINFO'
327** in 'lineinfo' signals the existence of this absolute information.)
328** Otherwise, store the difference from last line in 'lineinfo'.
329*/
330static void savelineinfo (FuncState *fs, Proto *f, int line) {
331 int linedif = line - fs->previousline;
332 int pc = fs->pc - 1; /* last instruction coded */
333 if (abs(linedif) >= LIMLINEDIFF || fs->iwthabs++ >= MAXIWTHABS) {
334 luaM_growvector(fs->ls->L, f->abslineinfo, fs->nabslineinfo,
335 f->sizeabslineinfo, AbsLineInfo, MAX_INT, "lines");
336 f->abslineinfo[fs->nabslineinfo].pc = pc;
337 f->abslineinfo[fs->nabslineinfo++].line = line;
338 linedif = ABSLINEINFO; /* signal that there is absolute information */
339 fs->iwthabs = 1; /* restart counter */
340 }
341 luaM_growvector(fs->ls->L, f->lineinfo, pc, f->sizelineinfo, ls_byte,
342 MAX_INT, "opcodes");
343 f->lineinfo[pc] = linedif;
344 fs->previousline = line; /* last line saved */
345}
346
347
348/*
349** Remove line information from the last instruction.
350** If line information for that instruction is absolute, set 'iwthabs'
351** above its max to force the new (replacing) instruction to have
352** absolute line info, too.
353*/
354static void removelastlineinfo (FuncState *fs) {
355 Proto *f = fs->f;
356 int pc = fs->pc - 1; /* last instruction coded */
357 if (f->lineinfo[pc] != ABSLINEINFO) { /* relative line info? */
358 fs->previousline -= f->lineinfo[pc]; /* correct last line saved */
359 fs->iwthabs--; /* undo previous increment */
360 }
361 else { /* absolute line information */
362 lua_assert(f->abslineinfo[fs->nabslineinfo - 1].pc == pc);
363 fs->nabslineinfo--; /* remove it */
364 fs->iwthabs = MAXIWTHABS + 1; /* force next line info to be absolute */
365 }
366}
367
368
369/*
370** Remove the last instruction created, correcting line information
371** accordingly.
372*/
373static void removelastinstruction (FuncState *fs) {
374 removelastlineinfo(fs);
375 fs->pc--;
376}
377
378
379/*
380** Emit instruction 'i', checking for array sizes and saving also its
381** line information. Return 'i' position.
382*/
383int luaK_code (FuncState *fs, Instruction i) {
384 Proto *f = fs->f;
385 /* put new instruction in code array */
386 luaM_growvector(fs->ls->L, f->code, fs->pc, f->sizecode, Instruction,
387 MAX_INT, "opcodes");
388 f->code[fs->pc++] = i;
389 savelineinfo(fs, f, fs->ls->lastline);
390 return fs->pc - 1; /* index of new instruction */
391}
392
393
394/*
395** Format and emit an 'iABC' instruction. (Assertions check consistency
396** of parameters versus opcode.)
397*/
398int luaK_codeABCk (FuncState *fs, OpCode o, int a, int b, int c, int k) {
399 lua_assert(getOpMode(o) == iABC);
400 lua_assert(a <= MAXARG_A && b <= MAXARG_B &&
401 c <= MAXARG_C && (k & ~1) == 0);
402 return luaK_code(fs, CREATE_ABCk(o, a, b, c, k));
403}
404
405
406/*
407** Format and emit an 'iABx' instruction.
408*/
409int luaK_codeABx (FuncState *fs, OpCode o, int a, unsigned int bc) {
410 lua_assert(getOpMode(o) == iABx);
411 lua_assert(a <= MAXARG_A && bc <= MAXARG_Bx);
412 return luaK_code(fs, CREATE_ABx(o, a, bc));
413}
414
415
416/*
417** Format and emit an 'iAsBx' instruction.
418*/
419static int codeAsBx (FuncState *fs, OpCode o, int a, int bc) {
420 unsigned int b = bc + OFFSET_sBx;
421 lua_assert(getOpMode(o) == iAsBx);
422 lua_assert(a <= MAXARG_A && b <= MAXARG_Bx);
423 return luaK_code(fs, CREATE_ABx(o, a, b));
424}
425
426
427/*
428** Format and emit an 'isJ' instruction.
429*/
430static int codesJ (FuncState *fs, OpCode o, int sj, int k) {
431 unsigned int j = sj + OFFSET_sJ;
432 lua_assert(getOpMode(o) == isJ);
433 lua_assert(j <= MAXARG_sJ && (k & ~1) == 0);
434 return luaK_code(fs, CREATE_sJ(o, j, k));
435}
436
437
438/*
439** Emit an "extra argument" instruction (format 'iAx')
440*/
441static int codeextraarg (FuncState *fs, int a) {
442 lua_assert(a <= MAXARG_Ax);
443 return luaK_code(fs, CREATE_Ax(OP_EXTRAARG, a));
444}
445
446
447/*
448** Emit a "load constant" instruction, using either 'OP_LOADK'
449** (if constant index 'k' fits in 18 bits) or an 'OP_LOADKX'
450** instruction with "extra argument".
451*/
452static int luaK_codek (FuncState *fs, int reg, int k) {
453 if (k <= MAXARG_Bx)
454 return luaK_codeABx(fs, OP_LOADK, reg, k);
455 else {
456 int p = luaK_codeABx(fs, OP_LOADKX, reg, 0);
457 codeextraarg(fs, k);
458 return p;
459 }
460}
461
462
463/*
464** Check register-stack level, keeping track of its maximum size
465** in field 'maxstacksize'
466*/
467void luaK_checkstack (FuncState *fs, int n) {
468 int newstack = fs->freereg + n;
469 if (newstack > fs->f->maxstacksize) {
470 if (newstack >= MAXREGS)
471 luaX_syntaxerror(fs->ls,
472 "function or expression needs too many registers");
473 fs->f->maxstacksize = cast_byte(newstack);
474 }
475}
476
477
478/*
479** Reserve 'n' registers in register stack
480*/
481void luaK_reserveregs (FuncState *fs, int n) {
482 luaK_checkstack(fs, n);
483 fs->freereg += n;
484}
485
486
487/*
488** Free register 'reg', if it is neither a constant index nor
489** a local variable.
490)
491*/
492static void freereg (FuncState *fs, int reg) {
493 if (reg >= luaY_nvarstack(fs)) {
494 fs->freereg--;
495 lua_assert(reg == fs->freereg);
496 }
497}
498
499
500/*
501** Free two registers in proper order
502*/
503static void freeregs (FuncState *fs, int r1, int r2) {
504 if (r1 > r2) {
505 freereg(fs, r1);
506 freereg(fs, r2);
507 }
508 else {
509 freereg(fs, r2);
510 freereg(fs, r1);
511 }
512}
513
514
515/*
516** Free register used by expression 'e' (if any)
517*/
518static void freeexp (FuncState *fs, expdesc *e) {
519 if (e->k == VNONRELOC)
520 freereg(fs, e->u.info);
521}
522
523
524/*
525** Free registers used by expressions 'e1' and 'e2' (if any) in proper
526** order.
527*/
528static void freeexps (FuncState *fs, expdesc *e1, expdesc *e2) {
529 int r1 = (e1->k == VNONRELOC) ? e1->u.info : -1;
530 int r2 = (e2->k == VNONRELOC) ? e2->u.info : -1;
531 freeregs(fs, r1, r2);
532}
533
534
535/*
536** Add constant 'v' to prototype's list of constants (field 'k').
537** Use scanner's table to cache position of constants in constant list
538** and try to reuse constants. Because some values should not be used
539** as keys (nil cannot be a key, integer keys can collapse with float
540** keys), the caller must provide a useful 'key' for indexing the cache.
541** Note that all functions share the same table, so entering or exiting
542** a function can make some indices wrong.
543*/
544static int addk (FuncState *fs, TValue *key, TValue *v) {
545 TValue val;
546 lua_State *L = fs->ls->L;
547 Proto *f = fs->f;
548 const TValue *idx = luaH_get(fs->ls->h, key); /* query scanner table */
549 int k, oldsize;
550 if (ttisinteger(idx)) { /* is there an index there? */
551 k = cast_int(ivalue(idx));
552 /* correct value? (warning: must distinguish floats from integers!) */
553 if (k < fs->nk && ttypetag(&f->k[k]) == ttypetag(v) &&
554 luaV_rawequalobj(&f->k[k], v))
555 return k; /* reuse index */
556 }
557 /* constant not found; create a new entry */
558 oldsize = f->sizek;
559 k = fs->nk;
560 /* numerical value does not need GC barrier;
561 table has no metatable, so it does not need to invalidate cache */
562 setivalue(&val, k);
563 luaH_finishset(L, fs->ls->h, key, idx, &val);
564 luaM_growvector(L, f->k, k, f->sizek, TValue, MAXARG_Ax, "constants");
565 while (oldsize < f->sizek) setnilvalue(&f->k[oldsize++]);
566 setobj(L, &f->k[k], v);
567 fs->nk++;
568 luaC_barrier(L, f, v);
569 return k;
570}
571
572
573/*
574** Add a string to list of constants and return its index.
575*/
576static int stringK (FuncState *fs, TString *s) {
577 TValue o;
578 setsvalue(fs->ls->L, &o, s);
579 return addk(fs, &o, &o); /* use string itself as key */
580}
581
582
583/*
584** Add an integer to list of constants and return its index.
585*/
586static int luaK_intK (FuncState *fs, lua_Integer n) {
587 TValue o;
588 setivalue(&o, n);
589 return addk(fs, &o, &o); /* use integer itself as key */
590}
591
592/*
593** Add a float to list of constants and return its index. Floats
594** with integral values need a different key, to avoid collision
595** with actual integers. To that, we add to the number its smaller
596** power-of-two fraction that is still significant in its scale.
597** For doubles, that would be 1/2^52.
598** (This method is not bulletproof: there may be another float
599** with that value, and for floats larger than 2^53 the result is
600** still an integer. At worst, this only wastes an entry with
601** a duplicate.)
602*/
603static int luaK_numberK (FuncState *fs, lua_Number r) {
604 TValue o;
605 lua_Integer ik;
606 setfltvalue(&o, r);
607 if (!luaV_flttointeger(r, &ik, F2Ieq)) /* not an integral value? */
608 return addk(fs, &o, &o); /* use number itself as key */
609 else { /* must build an alternative key */
610 const int nbm = l_floatatt(MANT_DIG);
611 const lua_Number q = l_mathop(ldexp)(l_mathop(1.0), -nbm + 1);
612 const lua_Number k = (ik == 0) ? q : r + r*q; /* new key */
613 TValue kv;
614 setfltvalue(&kv, k);
615 /* result is not an integral value, unless value is too large */
616 lua_assert(!luaV_flttointeger(k, &ik, F2Ieq) ||
617 l_mathop(fabs)(r) >= l_mathop(1e6));
618 return addk(fs, &kv, &o);
619 }
620}
621
622
623/*
624** Add a false to list of constants and return its index.
625*/
626static int boolF (FuncState *fs) {
627 TValue o;
628 setbfvalue(&o);
629 return addk(fs, &o, &o); /* use boolean itself as key */
630}
631
632
633/*
634** Add a true to list of constants and return its index.
635*/
636static int boolT (FuncState *fs) {
637 TValue o;
638 setbtvalue(&o);
639 return addk(fs, &o, &o); /* use boolean itself as key */
640}
641
642
643/*
644** Add nil to list of constants and return its index.
645*/
646static int nilK (FuncState *fs) {
647 TValue k, v;
648 setnilvalue(&v);
649 /* cannot use nil as key; instead use table itself to represent nil */
650 sethvalue(fs->ls->L, &k, fs->ls->h);
651 return addk(fs, &k, &v);
652}
653
654
655/*
656** Check whether 'i' can be stored in an 'sC' operand. Equivalent to
657** (0 <= int2sC(i) && int2sC(i) <= MAXARG_C) but without risk of
658** overflows in the hidden addition inside 'int2sC'.
659*/
660static int fitsC (lua_Integer i) {
661 return (l_castS2U(i) + OFFSET_sC <= cast_uint(MAXARG_C));
662}
663
664
665/*
666** Check whether 'i' can be stored in an 'sBx' operand.
667*/
668static int fitsBx (lua_Integer i) {
669 return (-OFFSET_sBx <= i && i <= MAXARG_Bx - OFFSET_sBx);
670}
671
672
673void luaK_int (FuncState *fs, int reg, lua_Integer i) {
674 if (fitsBx(i))
675 codeAsBx(fs, OP_LOADI, reg, cast_int(i));
676 else
677 luaK_codek(fs, reg, luaK_intK(fs, i));
678}
679
680
681static void luaK_float (FuncState *fs, int reg, lua_Number f) {
682 lua_Integer fi;
683 if (luaV_flttointeger(f, &fi, F2Ieq) && fitsBx(fi))
684 codeAsBx(fs, OP_LOADF, reg, cast_int(fi));
685 else
686 luaK_codek(fs, reg, luaK_numberK(fs, f));
687}
688
689
690/*
691** Convert a constant in 'v' into an expression description 'e'
692*/
693static void const2exp (TValue *v, expdesc *e) {
694 switch (ttypetag(v)) {
695 case LUA_VNUMINT:
696 e->k = VKINT; e->u.ival = ivalue(v);
697 break;
698 case LUA_VNUMFLT:
699 e->k = VKFLT; e->u.nval = fltvalue(v);
700 break;
701 case LUA_VFALSE:
702 e->k = VFALSE;
703 break;
704 case LUA_VTRUE:
705 e->k = VTRUE;
706 break;
707 case LUA_VNIL:
708 e->k = VNIL;
709 break;
710 case LUA_VSHRSTR: case LUA_VLNGSTR:
711 e->k = VKSTR; e->u.strval = tsvalue(v);
712 break;
713 default: lua_assert(0);
714 }
715}
716
717
718/*
719** Fix an expression to return the number of results 'nresults'.
720** 'e' must be a multi-ret expression (function call or vararg).
721*/
722void luaK_setreturns (FuncState *fs, expdesc *e, int nresults) {
723 Instruction *pc = &getinstruction(fs, e);
724 if (e->k == VCALL) /* expression is an open function call? */
725 SETARG_C(*pc, nresults + 1);
726 else {
727 lua_assert(e->k == VVARARG);
728 SETARG_C(*pc, nresults + 1);
729 SETARG_A(*pc, fs->freereg);
730 luaK_reserveregs(fs, 1);
731 }
732}
733
734
735/*
736** Convert a VKSTR to a VK
737*/
738static void str2K (FuncState *fs, expdesc *e) {
739 lua_assert(e->k == VKSTR);
740 e->u.info = stringK(fs, e->u.strval);
741 e->k = VK;
742}
743
744
745/*
746** Fix an expression to return one result.
747** If expression is not a multi-ret expression (function call or
748** vararg), it already returns one result, so nothing needs to be done.
749** Function calls become VNONRELOC expressions (as its result comes
750** fixed in the base register of the call), while vararg expressions
751** become VRELOC (as OP_VARARG puts its results where it wants).
752** (Calls are created returning one result, so that does not need
753** to be fixed.)
754*/
755void luaK_setoneret (FuncState *fs, expdesc *e) {
756 if (e->k == VCALL) { /* expression is an open function call? */
757 /* already returns 1 value */
758 lua_assert(GETARG_C(getinstruction(fs, e)) == 2);
759 e->k = VNONRELOC; /* result has fixed position */
760 e->u.info = GETARG_A(getinstruction(fs, e));
761 }
762 else if (e->k == VVARARG) {
763 SETARG_C(getinstruction(fs, e), 2);
764 e->k = VRELOC; /* can relocate its simple result */
765 }
766}
767
768
769/*
770** Ensure that expression 'e' is not a variable (nor a <const>).
771** (Expression still may have jump lists.)
772*/
773void luaK_dischargevars (FuncState *fs, expdesc *e) {
774 switch (e->k) {
775 case VCONST: {
776 const2exp(const2val(fs, e), e);
777 break;
778 }
779 case VLOCAL: { /* already in a register */
780 int temp = e->u.var.ridx;
781 e->u.info = temp; /* (can't do a direct assignment; values overlap) */
782 e->k = VNONRELOC; /* becomes a non-relocatable value */
783 break;
784 }
785 case VUPVAL: { /* move value to some (pending) register */
786 e->u.info = luaK_codeABC(fs, OP_GETUPVAL, 0, e->u.info, 0);
787 e->k = VRELOC;
788 break;
789 }
790 case VINDEXUP: {
791 e->u.info = luaK_codeABC(fs, OP_GETTABUP, 0, e->u.ind.t, e->u.ind.idx);
792 e->k = VRELOC;
793 break;
794 }
795 case VINDEXI: {
796 freereg(fs, e->u.ind.t);
797 e->u.info = luaK_codeABC(fs, OP_GETI, 0, e->u.ind.t, e->u.ind.idx);
798 e->k = VRELOC;
799 break;
800 }
801 case VINDEXSTR: {
802 freereg(fs, e->u.ind.t);
803 e->u.info = luaK_codeABC(fs, OP_GETFIELD, 0, e->u.ind.t, e->u.ind.idx);
804 e->k = VRELOC;
805 break;
806 }
807 case VINDEXED: {
808 freeregs(fs, e->u.ind.t, e->u.ind.idx);
809 e->u.info = luaK_codeABC(fs, OP_GETTABLE, 0, e->u.ind.t, e->u.ind.idx);
810 e->k = VRELOC;
811 break;
812 }
813 case VVARARG: case VCALL: {
814 luaK_setoneret(fs, e);
815 break;
816 }
817 default: break; /* there is one value available (somewhere) */
818 }
819}
820
821
822/*
823** Ensure expression value is in register 'reg', making 'e' a
824** non-relocatable expression.
825** (Expression still may have jump lists.)
826*/
827static void discharge2reg (FuncState *fs, expdesc *e, int reg) {
828 luaK_dischargevars(fs, e);
829 switch (e->k) {
830 case VNIL: {
831 luaK_nil(fs, reg, 1);
832 break;
833 }
834 case VFALSE: {
835 luaK_codeABC(fs, OP_LOADFALSE, reg, 0, 0);
836 break;
837 }
838 case VTRUE: {
839 luaK_codeABC(fs, OP_LOADTRUE, reg, 0, 0);
840 break;
841 }
842 case VKSTR: {
843 str2K(fs, e);
844 } /* FALLTHROUGH */
845 case VK: {
846 luaK_codek(fs, reg, e->u.info);
847 break;
848 }
849 case VKFLT: {
850 luaK_float(fs, reg, e->u.nval);
851 break;
852 }
853 case VKINT: {
854 luaK_int(fs, reg, e->u.ival);
855 break;
856 }
857 case VRELOC: {
858 Instruction *pc = &getinstruction(fs, e);
859 SETARG_A(*pc, reg); /* instruction will put result in 'reg' */
860 break;
861 }
862 case VNONRELOC: {
863 if (reg != e->u.info)
864 luaK_codeABC(fs, OP_MOVE, reg, e->u.info, 0);
865 break;
866 }
867 default: {
868 lua_assert(e->k == VJMP);
869 return; /* nothing to do... */
870 }
871 }
872 e->u.info = reg;
873 e->k = VNONRELOC;
874}
875
876
877/*
878** Ensure expression value is in a register, making 'e' a
879** non-relocatable expression.
880** (Expression still may have jump lists.)
881*/
882static void discharge2anyreg (FuncState *fs, expdesc *e) {
883 if (e->k != VNONRELOC) { /* no fixed register yet? */
884 luaK_reserveregs(fs, 1); /* get a register */
885 discharge2reg(fs, e, fs->freereg-1); /* put value there */
886 }
887}
888
889
890static int code_loadbool (FuncState *fs, int A, OpCode op) {
891 luaK_getlabel(fs); /* those instructions may be jump targets */
892 return luaK_codeABC(fs, op, A, 0, 0);
893}
894
895
896/*
897** check whether list has any jump that do not produce a value
898** or produce an inverted value
899*/
900static int need_value (FuncState *fs, int list) {
901 for (; list != NO_JUMP; list = getjump(fs, list)) {
902 Instruction i = *getjumpcontrol(fs, list);
903 if (GET_OPCODE(i) != OP_TESTSET) return 1;
904 }
905 return 0; /* not found */
906}
907
908
909/*
910** Ensures final expression result (which includes results from its
911** jump lists) is in register 'reg'.
912** If expression has jumps, need to patch these jumps either to
913** its final position or to "load" instructions (for those tests
914** that do not produce values).
915*/
916static void exp2reg (FuncState *fs, expdesc *e, int reg) {
917 discharge2reg(fs, e, reg);
918 if (e->k == VJMP) /* expression itself is a test? */
919 luaK_concat(fs, &e->t, e->u.info); /* put this jump in 't' list */
920 if (hasjumps(e)) {
921 int final; /* position after whole expression */
922 int p_f = NO_JUMP; /* position of an eventual LOAD false */
923 int p_t = NO_JUMP; /* position of an eventual LOAD true */
924 if (need_value(fs, e->t) || need_value(fs, e->f)) {
925 int fj = (e->k == VJMP) ? NO_JUMP : luaK_jump(fs);
926 p_f = code_loadbool(fs, reg, OP_LFALSESKIP); /* skip next inst. */
927 p_t = code_loadbool(fs, reg, OP_LOADTRUE);
928 /* jump around these booleans if 'e' is not a test */
929 luaK_patchtohere(fs, fj);
930 }
931 final = luaK_getlabel(fs);
932 patchlistaux(fs, e->f, final, reg, p_f);
933 patchlistaux(fs, e->t, final, reg, p_t);
934 }
935 e->f = e->t = NO_JUMP;
936 e->u.info = reg;
937 e->k = VNONRELOC;
938}
939
940
941/*
942** Ensures final expression result is in next available register.
943*/
944void luaK_exp2nextreg (FuncState *fs, expdesc *e) {
945 luaK_dischargevars(fs, e);
946 freeexp(fs, e);
947 luaK_reserveregs(fs, 1);
948 exp2reg(fs, e, fs->freereg - 1);
949}
950
951
952/*
953** Ensures final expression result is in some (any) register
954** and return that register.
955*/
956int luaK_exp2anyreg (FuncState *fs, expdesc *e) {
957 luaK_dischargevars(fs, e);
958 if (e->k == VNONRELOC) { /* expression already has a register? */
959 if (!hasjumps(e)) /* no jumps? */
960 return e->u.info; /* result is already in a register */
961 if (e->u.info >= luaY_nvarstack(fs)) { /* reg. is not a local? */
962 exp2reg(fs, e, e->u.info); /* put final result in it */
963 return e->u.info;
964 }
965 /* else expression has jumps and cannot change its register
966 to hold the jump values, because it is a local variable.
967 Go through to the default case. */
968 }
969 luaK_exp2nextreg(fs, e); /* default: use next available register */
970 return e->u.info;
971}
972
973
974/*
975** Ensures final expression result is either in a register
976** or in an upvalue.
977*/
978void luaK_exp2anyregup (FuncState *fs, expdesc *e) {
979 if (e->k != VUPVAL || hasjumps(e))
980 luaK_exp2anyreg(fs, e);
981}
982
983
984/*
985** Ensures final expression result is either in a register
986** or it is a constant.
987*/
988void luaK_exp2val (FuncState *fs, expdesc *e) {
989 if (e->k == VJMP || hasjumps(e))
990 luaK_exp2anyreg(fs, e);
991 else
992 luaK_dischargevars(fs, e);
993}
994
995
996/*
997** Try to make 'e' a K expression with an index in the range of R/K
998** indices. Return true iff succeeded.
999*/
1000static int luaK_exp2K (FuncState *fs, expdesc *e) {
1001 if (!hasjumps(e)) {
1002 int info;
1003 switch (e->k) { /* move constants to 'k' */
1004 case VTRUE: info = boolT(fs); break;
1005 case VFALSE: info = boolF(fs); break;
1006 case VNIL: info = nilK(fs); break;
1007 case VKINT: info = luaK_intK(fs, e->u.ival); break;
1008 case VKFLT: info = luaK_numberK(fs, e->u.nval); break;
1009 case VKSTR: info = stringK(fs, e->u.strval); break;
1010 case VK: info = e->u.info; break;
1011 default: return 0; /* not a constant */
1012 }
1013 if (info <= MAXINDEXRK) { /* does constant fit in 'argC'? */
1014 e->k = VK; /* make expression a 'K' expression */
1015 e->u.info = info;
1016 return 1;
1017 }
1018 }
1019 /* else, expression doesn't fit; leave it unchanged */
1020 return 0;
1021}
1022
1023
1024/*
1025** Ensures final expression result is in a valid R/K index
1026** (that is, it is either in a register or in 'k' with an index
1027** in the range of R/K indices).
1028** Returns 1 iff expression is K.
1029*/
1030static int exp2RK (FuncState *fs, expdesc *e) {
1031 if (luaK_exp2K(fs, e))
1032 return 1;
1033 else { /* not a constant in the right range: put it in a register */
1034 luaK_exp2anyreg(fs, e);
1035 return 0;
1036 }
1037}
1038
1039
1040static void codeABRK (FuncState *fs, OpCode o, int a, int b,
1041 expdesc *ec) {
1042 int k = exp2RK(fs, ec);
1043 luaK_codeABCk(fs, o, a, b, ec->u.info, k);
1044}
1045
1046
1047/*
1048** Generate code to store result of expression 'ex' into variable 'var'.
1049*/
1050void luaK_storevar (FuncState *fs, expdesc *var, expdesc *ex) {
1051 switch (var->k) {
1052 case VLOCAL: {
1053 freeexp(fs, ex);
1054 exp2reg(fs, ex, var->u.var.ridx); /* compute 'ex' into proper place */
1055 return;
1056 }
1057 case VUPVAL: {
1058 int e = luaK_exp2anyreg(fs, ex);
1059 luaK_codeABC(fs, OP_SETUPVAL, e, var->u.info, 0);
1060 break;
1061 }
1062 case VINDEXUP: {
1063 codeABRK(fs, OP_SETTABUP, var->u.ind.t, var->u.ind.idx, ex);
1064 break;
1065 }
1066 case VINDEXI: {
1067 codeABRK(fs, OP_SETI, var->u.ind.t, var->u.ind.idx, ex);
1068 break;
1069 }
1070 case VINDEXSTR: {
1071 codeABRK(fs, OP_SETFIELD, var->u.ind.t, var->u.ind.idx, ex);
1072 break;
1073 }
1074 case VINDEXED: {
1075 codeABRK(fs, OP_SETTABLE, var->u.ind.t, var->u.ind.idx, ex);
1076 break;
1077 }
1078 default: lua_assert(0); /* invalid var kind to store */
1079 }
1080 freeexp(fs, ex);
1081}
1082
1083
1084/*
1085** Emit SELF instruction (convert expression 'e' into 'e:key(e,').
1086*/
1087void luaK_self (FuncState *fs, expdesc *e, expdesc *key) {
1088 int ereg;
1089 luaK_exp2anyreg(fs, e);
1090 ereg = e->u.info; /* register where 'e' was placed */
1091 freeexp(fs, e);
1092 e->u.info = fs->freereg; /* base register for op_self */
1093 e->k = VNONRELOC; /* self expression has a fixed register */
1094 luaK_reserveregs(fs, 2); /* function and 'self' produced by op_self */
1095 codeABRK(fs, OP_SELF, e->u.info, ereg, key);
1096 freeexp(fs, key);
1097}
1098
1099
1100/*
1101** Negate condition 'e' (where 'e' is a comparison).
1102*/
1103static void negatecondition (FuncState *fs, expdesc *e) {
1104 Instruction *pc = getjumpcontrol(fs, e->u.info);
1105 lua_assert(testTMode(GET_OPCODE(*pc)) && GET_OPCODE(*pc) != OP_TESTSET &&
1106 GET_OPCODE(*pc) != OP_TEST);
1107 SETARG_k(*pc, (GETARG_k(*pc) ^ 1));
1108}
1109
1110
1111/*
1112** Emit instruction to jump if 'e' is 'cond' (that is, if 'cond'
1113** is true, code will jump if 'e' is true.) Return jump position.
1114** Optimize when 'e' is 'not' something, inverting the condition
1115** and removing the 'not'.
1116*/
1117static int jumponcond (FuncState *fs, expdesc *e, int cond) {
1118 if (e->k == VRELOC) {
1119 Instruction ie = getinstruction(fs, e);
1120 if (GET_OPCODE(ie) == OP_NOT) {
1121 removelastinstruction(fs); /* remove previous OP_NOT */
1122 return condjump(fs, OP_TEST, GETARG_B(ie), 0, 0, !cond);
1123 }
1124 /* else go through */
1125 }
1126 discharge2anyreg(fs, e);
1127 freeexp(fs, e);
1128 return condjump(fs, OP_TESTSET, NO_REG, e->u.info, 0, cond);
1129}
1130
1131
1132/*
1133** Emit code to go through if 'e' is true, jump otherwise.
1134*/
1135void luaK_goiftrue (FuncState *fs, expdesc *e) {
1136 int pc; /* pc of new jump */
1137 luaK_dischargevars(fs, e);
1138 switch (e->k) {
1139 case VJMP: { /* condition? */
1140 negatecondition(fs, e); /* jump when it is false */
1141 pc = e->u.info; /* save jump position */
1142 break;
1143 }
1144 case VK: case VKFLT: case VKINT: case VKSTR: case VTRUE: {
1145 pc = NO_JUMP; /* always true; do nothing */
1146 break;
1147 }
1148 default: {
1149 pc = jumponcond(fs, e, 0); /* jump when false */
1150 break;
1151 }
1152 }
1153 luaK_concat(fs, &e->f, pc); /* insert new jump in false list */
1154 luaK_patchtohere(fs, e->t); /* true list jumps to here (to go through) */
1155 e->t = NO_JUMP;
1156}
1157
1158
1159/*
1160** Emit code to go through if 'e' is false, jump otherwise.
1161*/
1162void luaK_goiffalse (FuncState *fs, expdesc *e) {
1163 int pc; /* pc of new jump */
1164 luaK_dischargevars(fs, e);
1165 switch (e->k) {
1166 case VJMP: {
1167 pc = e->u.info; /* already jump if true */
1168 break;
1169 }
1170 case VNIL: case VFALSE: {
1171 pc = NO_JUMP; /* always false; do nothing */
1172 break;
1173 }
1174 default: {
1175 pc = jumponcond(fs, e, 1); /* jump if true */
1176 break;
1177 }
1178 }
1179 luaK_concat(fs, &e->t, pc); /* insert new jump in 't' list */
1180 luaK_patchtohere(fs, e->f); /* false list jumps to here (to go through) */
1181 e->f = NO_JUMP;
1182}
1183
1184
1185/*
1186** Code 'not e', doing constant folding.
1187*/
1188static void codenot (FuncState *fs, expdesc *e) {
1189 switch (e->k) {
1190 case VNIL: case VFALSE: {
1191 e->k = VTRUE; /* true == not nil == not false */
1192 break;
1193 }
1194 case VK: case VKFLT: case VKINT: case VKSTR: case VTRUE: {
1195 e->k = VFALSE; /* false == not "x" == not 0.5 == not 1 == not true */
1196 break;
1197 }
1198 case VJMP: {
1199 negatecondition(fs, e);
1200 break;
1201 }
1202 case VRELOC:
1203 case VNONRELOC: {
1204 discharge2anyreg(fs, e);
1205 freeexp(fs, e);
1206 e->u.info = luaK_codeABC(fs, OP_NOT, 0, e->u.info, 0);
1207 e->k = VRELOC;
1208 break;
1209 }
1210 default: lua_assert(0); /* cannot happen */
1211 }
1212 /* interchange true and false lists */
1213 { int temp = e->f; e->f = e->t; e->t = temp; }
1214 removevalues(fs, e->f); /* values are useless when negated */
1215 removevalues(fs, e->t);
1216}
1217
1218
1219/*
1220** Check whether expression 'e' is a short literal string
1221*/
1222static int isKstr (FuncState *fs, expdesc *e) {
1223 return (e->k == VK && !hasjumps(e) && e->u.info <= MAXARG_B &&
1224 ttisshrstring(&fs->f->k[e->u.info]));
1225}
1226
1227/*
1228** Check whether expression 'e' is a literal integer.
1229*/
1230static int isKint (expdesc *e) {
1231 return (e->k == VKINT && !hasjumps(e));
1232}
1233
1234
1235/*
1236** Check whether expression 'e' is a literal integer in
1237** proper range to fit in register C
1238*/
1239static int isCint (expdesc *e) {
1240 return isKint(e) && (l_castS2U(e->u.ival) <= l_castS2U(MAXARG_C));
1241}
1242
1243
1244/*
1245** Check whether expression 'e' is a literal integer in
1246** proper range to fit in register sC
1247*/
1248static int isSCint (expdesc *e) {
1249 return isKint(e) && fitsC(e->u.ival);
1250}
1251
1252
1253/*
1254** Check whether expression 'e' is a literal integer or float in
1255** proper range to fit in a register (sB or sC).
1256*/
1257static int isSCnumber (expdesc *e, int *pi, int *isfloat) {
1258 lua_Integer i;
1259 if (e->k == VKINT)
1260 i = e->u.ival;
1261 else if (e->k == VKFLT && luaV_flttointeger(e->u.nval, &i, F2Ieq))
1262 *isfloat = 1;
1263 else
1264 return 0; /* not a number */
1265 if (!hasjumps(e) && fitsC(i)) {
1266 *pi = int2sC(cast_int(i));
1267 return 1;
1268 }
1269 else
1270 return 0;
1271}
1272
1273
1274/*
1275** Create expression 't[k]'. 't' must have its final result already in a
1276** register or upvalue. Upvalues can only be indexed by literal strings.
1277** Keys can be literal strings in the constant table or arbitrary
1278** values in registers.
1279*/
1280void luaK_indexed (FuncState *fs, expdesc *t, expdesc *k) {
1281 if (k->k == VKSTR)
1282 str2K(fs, k);
1283 lua_assert(!hasjumps(t) &&
1284 (t->k == VLOCAL || t->k == VNONRELOC || t->k == VUPVAL));
1285 if (t->k == VUPVAL && !isKstr(fs, k)) /* upvalue indexed by non 'Kstr'? */
1286 luaK_exp2anyreg(fs, t); /* put it in a register */
1287 if (t->k == VUPVAL) {
1288 int temp = t->u.info; /* upvalue index */
1289 lua_assert(isKstr(fs, k));
1290 t->u.ind.t = temp; /* (can't do a direct assignment; values overlap) */
1291 t->u.ind.idx = k->u.info; /* literal short string */
1292 t->k = VINDEXUP;
1293 }
1294 else {
1295 /* register index of the table */
1296 t->u.ind.t = (t->k == VLOCAL) ? t->u.var.ridx: t->u.info;
1297 if (isKstr(fs, k)) {
1298 t->u.ind.idx = k->u.info; /* literal short string */
1299 t->k = VINDEXSTR;
1300 }
1301 else if (isCint(k)) {
1302 t->u.ind.idx = cast_int(k->u.ival); /* int. constant in proper range */
1303 t->k = VINDEXI;
1304 }
1305 else {
1306 t->u.ind.idx = luaK_exp2anyreg(fs, k); /* register */
1307 t->k = VINDEXED;
1308 }
1309 }
1310}
1311
1312
1313/*
1314** Return false if folding can raise an error.
1315** Bitwise operations need operands convertible to integers; division
1316** operations cannot have 0 as divisor.
1317*/
1318static int validop (int op, TValue *v1, TValue *v2) {
1319 switch (op) {
1320 case LUA_OPBAND: case LUA_OPBOR: case LUA_OPBXOR:
1321 case LUA_OPSHL: case LUA_OPSHR: case LUA_OPBNOT: { /* conversion errors */
1322 lua_Integer i;
1323 return (luaV_tointegerns(v1, &i, LUA_FLOORN2I) &&
1324 luaV_tointegerns(v2, &i, LUA_FLOORN2I));
1325 }
1326 case LUA_OPDIV: case LUA_OPIDIV: case LUA_OPMOD: /* division by 0 */
1327 return (nvalue(v2) != 0);
1328 default: return 1; /* everything else is valid */
1329 }
1330}
1331
1332
1333/*
1334** Try to "constant-fold" an operation; return 1 iff successful.
1335** (In this case, 'e1' has the final result.)
1336*/
1337static int constfolding (FuncState *fs, int op, expdesc *e1,
1338 const expdesc *e2) {
1339 TValue v1, v2, res;
1340 if (!tonumeral(e1, &v1) || !tonumeral(e2, &v2) || !validop(op, &v1, &v2))
1341 return 0; /* non-numeric operands or not safe to fold */
1342 luaO_rawarith(fs->ls->L, op, &v1, &v2, &res); /* does operation */
1343 if (ttisinteger(&res)) {
1344 e1->k = VKINT;
1345 e1->u.ival = ivalue(&res);
1346 }
1347 else { /* folds neither NaN nor 0.0 (to avoid problems with -0.0) */
1348 lua_Number n = fltvalue(&res);
1349 if (luai_numisnan(n) || n == 0)
1350 return 0;
1351 e1->k = VKFLT;
1352 e1->u.nval = n;
1353 }
1354 return 1;
1355}
1356
1357
1358/*
1359** Convert a BinOpr to an OpCode (ORDER OPR - ORDER OP)
1360*/
1361l_sinline OpCode binopr2op (BinOpr opr, BinOpr baser, OpCode base) {
1362 lua_assert(baser <= opr &&
1363 ((baser == OPR_ADD && opr <= OPR_SHR) ||
1364 (baser == OPR_LT && opr <= OPR_LE)));
1365 return cast(OpCode, (cast_int(opr) - cast_int(baser)) + cast_int(base));
1366}
1367
1368
1369/*
1370** Convert a UnOpr to an OpCode (ORDER OPR - ORDER OP)
1371*/
1372l_sinline OpCode unopr2op (UnOpr opr) {
1373 return cast(OpCode, (cast_int(opr) - cast_int(OPR_MINUS)) +
1374 cast_int(OP_UNM));
1375}
1376
1377
1378/*
1379** Convert a BinOpr to a tag method (ORDER OPR - ORDER TM)
1380*/
1381l_sinline TMS binopr2TM (BinOpr opr) {
1382 lua_assert(OPR_ADD <= opr && opr <= OPR_SHR);
1383 return cast(TMS, (cast_int(opr) - cast_int(OPR_ADD)) + cast_int(TM_ADD));
1384}
1385
1386
1387/*
1388** Emit code for unary expressions that "produce values"
1389** (everything but 'not').
1390** Expression to produce final result will be encoded in 'e'.
1391*/
1392static void codeunexpval (FuncState *fs, OpCode op, expdesc *e, int line) {
1393 int r = luaK_exp2anyreg(fs, e); /* opcodes operate only on registers */
1394 freeexp(fs, e);
1395 e->u.info = luaK_codeABC(fs, op, 0, r, 0); /* generate opcode */
1396 e->k = VRELOC; /* all those operations are relocatable */
1397 luaK_fixline(fs, line);
1398}
1399
1400
1401/*
1402** Emit code for binary expressions that "produce values"
1403** (everything but logical operators 'and'/'or' and comparison
1404** operators).
1405** Expression to produce final result will be encoded in 'e1'.
1406*/
1407static void finishbinexpval (FuncState *fs, expdesc *e1, expdesc *e2,
1408 OpCode op, int v2, int flip, int line,
1409 OpCode mmop, TMS event) {
1410 int v1 = luaK_exp2anyreg(fs, e1);
1411 int pc = luaK_codeABCk(fs, op, 0, v1, v2, 0);
1412 freeexps(fs, e1, e2);
1413 e1->u.info = pc;
1414 e1->k = VRELOC; /* all those operations are relocatable */
1415 luaK_fixline(fs, line);
1416 luaK_codeABCk(fs, mmop, v1, v2, event, flip); /* to call metamethod */
1417 luaK_fixline(fs, line);
1418}
1419
1420
1421/*
1422** Emit code for binary expressions that "produce values" over
1423** two registers.
1424*/
1425static void codebinexpval (FuncState *fs, BinOpr opr,
1426 expdesc *e1, expdesc *e2, int line) {
1427 OpCode op = binopr2op(opr, OPR_ADD, OP_ADD);
1428 int v2 = luaK_exp2anyreg(fs, e2); /* make sure 'e2' is in a register */
1429 /* 'e1' must be already in a register or it is a constant */
1430 lua_assert((VNIL <= e1->k && e1->k <= VKSTR) ||
1431 e1->k == VNONRELOC || e1->k == VRELOC);
1432 lua_assert(OP_ADD <= op && op <= OP_SHR);
1433 finishbinexpval(fs, e1, e2, op, v2, 0, line, OP_MMBIN, binopr2TM(opr));
1434}
1435
1436
1437/*
1438** Code binary operators with immediate operands.
1439*/
1440static void codebini (FuncState *fs, OpCode op,
1441 expdesc *e1, expdesc *e2, int flip, int line,
1442 TMS event) {
1443 int v2 = int2sC(cast_int(e2->u.ival)); /* immediate operand */
1444 lua_assert(e2->k == VKINT);
1445 finishbinexpval(fs, e1, e2, op, v2, flip, line, OP_MMBINI, event);
1446}
1447
1448
1449/*
1450** Code binary operators with K operand.
1451*/
1452static void codebinK (FuncState *fs, BinOpr opr,
1453 expdesc *e1, expdesc *e2, int flip, int line) {
1454 TMS event = binopr2TM(opr);
1455 int v2 = e2->u.info; /* K index */
1456 OpCode op = binopr2op(opr, OPR_ADD, OP_ADDK);
1457 finishbinexpval(fs, e1, e2, op, v2, flip, line, OP_MMBINK, event);
1458}
1459
1460
1461/* Try to code a binary operator negating its second operand.
1462** For the metamethod, 2nd operand must keep its original value.
1463*/
1464static int finishbinexpneg (FuncState *fs, expdesc *e1, expdesc *e2,
1465 OpCode op, int line, TMS event) {
1466 if (!isKint(e2))
1467 return 0; /* not an integer constant */
1468 else {
1469 lua_Integer i2 = e2->u.ival;
1470 if (!(fitsC(i2) && fitsC(-i2)))
1471 return 0; /* not in the proper range */
1472 else { /* operating a small integer constant */
1473 int v2 = cast_int(i2);
1474 finishbinexpval(fs, e1, e2, op, int2sC(-v2), 0, line, OP_MMBINI, event);
1475 /* correct metamethod argument */
1476 SETARG_B(fs->f->code[fs->pc - 1], int2sC(v2));
1477 return 1; /* successfully coded */
1478 }
1479 }
1480}
1481
1482
1483static void swapexps (expdesc *e1, expdesc *e2) {
1484 expdesc temp = *e1; *e1 = *e2; *e2 = temp; /* swap 'e1' and 'e2' */
1485}
1486
1487
1488/*
1489** Code binary operators with no constant operand.
1490*/
1491static void codebinNoK (FuncState *fs, BinOpr opr,
1492 expdesc *e1, expdesc *e2, int flip, int line) {
1493 if (flip)
1494 swapexps(e1, e2); /* back to original order */
1495 codebinexpval(fs, opr, e1, e2, line); /* use standard operators */
1496}
1497
1498
1499/*
1500** Code arithmetic operators ('+', '-', ...). If second operand is a
1501** constant in the proper range, use variant opcodes with K operands.
1502*/
1503static void codearith (FuncState *fs, BinOpr opr,
1504 expdesc *e1, expdesc *e2, int flip, int line) {
1505 if (tonumeral(e2, NULL) && luaK_exp2K(fs, e2)) /* K operand? */
1506 codebinK(fs, opr, e1, e2, flip, line);
1507 else /* 'e2' is neither an immediate nor a K operand */
1508 codebinNoK(fs, opr, e1, e2, flip, line);
1509}
1510
1511
1512/*
1513** Code commutative operators ('+', '*'). If first operand is a
1514** numeric constant, change order of operands to try to use an
1515** immediate or K operator.
1516*/
1517static void codecommutative (FuncState *fs, BinOpr op,
1518 expdesc *e1, expdesc *e2, int line) {
1519 int flip = 0;
1520 if (tonumeral(e1, NULL)) { /* is first operand a numeric constant? */
1521 swapexps(e1, e2); /* change order */
1522 flip = 1;
1523 }
1524 if (op == OPR_ADD && isSCint(e2)) /* immediate operand? */
1525 codebini(fs, OP_ADDI, e1, e2, flip, line, TM_ADD);
1526 else
1527 codearith(fs, op, e1, e2, flip, line);
1528}
1529
1530
1531/*
1532** Code bitwise operations; they are all commutative, so the function
1533** tries to put an integer constant as the 2nd operand (a K operand).
1534*/
1535static void codebitwise (FuncState *fs, BinOpr opr,
1536 expdesc *e1, expdesc *e2, int line) {
1537 int flip = 0;
1538 if (e1->k == VKINT) {
1539 swapexps(e1, e2); /* 'e2' will be the constant operand */
1540 flip = 1;
1541 }
1542 if (e2->k == VKINT && luaK_exp2K(fs, e2)) /* K operand? */
1543 codebinK(fs, opr, e1, e2, flip, line);
1544 else /* no constants */
1545 codebinNoK(fs, opr, e1, e2, flip, line);
1546}
1547
1548
1549/*
1550** Emit code for order comparisons. When using an immediate operand,
1551** 'isfloat' tells whether the original value was a float.
1552*/
1553static void codeorder (FuncState *fs, BinOpr opr, expdesc *e1, expdesc *e2) {
1554 int r1, r2;
1555 int im;
1556 int isfloat = 0;
1557 OpCode op;
1558 if (isSCnumber(e2, &im, &isfloat)) {
1559 /* use immediate operand */
1560 r1 = luaK_exp2anyreg(fs, e1);
1561 r2 = im;
1562 op = binopr2op(opr, OPR_LT, OP_LTI);
1563 }
1564 else if (isSCnumber(e1, &im, &isfloat)) {
1565 /* transform (A < B) to (B > A) and (A <= B) to (B >= A) */
1566 r1 = luaK_exp2anyreg(fs, e2);
1567 r2 = im;
1568 op = binopr2op(opr, OPR_LT, OP_GTI);
1569 }
1570 else { /* regular case, compare two registers */
1571 r1 = luaK_exp2anyreg(fs, e1);
1572 r2 = luaK_exp2anyreg(fs, e2);
1573 op = binopr2op(opr, OPR_LT, OP_LT);
1574 }
1575 freeexps(fs, e1, e2);
1576 e1->u.info = condjump(fs, op, r1, r2, isfloat, 1);
1577 e1->k = VJMP;
1578}
1579
1580
1581/*
1582** Emit code for equality comparisons ('==', '~=').
1583** 'e1' was already put as RK by 'luaK_infix'.
1584*/
1585static void codeeq (FuncState *fs, BinOpr opr, expdesc *e1, expdesc *e2) {
1586 int r1, r2;
1587 int im;
1588 int isfloat = 0; /* not needed here, but kept for symmetry */
1589 OpCode op;
1590 if (e1->k != VNONRELOC) {
1591 lua_assert(e1->k == VK || e1->k == VKINT || e1->k == VKFLT);
1592 swapexps(e1, e2);
1593 }
1594 r1 = luaK_exp2anyreg(fs, e1); /* 1st expression must be in register */
1595 if (isSCnumber(e2, &im, &isfloat)) {
1596 op = OP_EQI;
1597 r2 = im; /* immediate operand */
1598 }
1599 else if (exp2RK(fs, e2)) { /* 2nd expression is constant? */
1600 op = OP_EQK;
1601 r2 = e2->u.info; /* constant index */
1602 }
1603 else {
1604 op = OP_EQ; /* will compare two registers */
1605 r2 = luaK_exp2anyreg(fs, e2);
1606 }
1607 freeexps(fs, e1, e2);
1608 e1->u.info = condjump(fs, op, r1, r2, isfloat, (opr == OPR_EQ));
1609 e1->k = VJMP;
1610}
1611
1612
1613/*
1614** Apply prefix operation 'op' to expression 'e'.
1615*/
1616void luaK_prefix (FuncState *fs, UnOpr opr, expdesc *e, int line) {
1617 static const expdesc ef = {VKINT, {0}, NO_JUMP, NO_JUMP};
1618 luaK_dischargevars(fs, e);
1619 switch (opr) {
1620 case OPR_MINUS: case OPR_BNOT: /* use 'ef' as fake 2nd operand */
1621 if (constfolding(fs, opr + LUA_OPUNM, e, &ef))
1622 break;
1623 /* else */ /* FALLTHROUGH */
1624 case OPR_LEN:
1625 codeunexpval(fs, unopr2op(opr), e, line);
1626 break;
1627 case OPR_NOT: codenot(fs, e); break;
1628 default: lua_assert(0);
1629 }
1630}
1631
1632
1633/*
1634** Process 1st operand 'v' of binary operation 'op' before reading
1635** 2nd operand.
1636*/
1637void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) {
1638 luaK_dischargevars(fs, v);
1639 switch (op) {
1640 case OPR_AND: {
1641 luaK_goiftrue(fs, v); /* go ahead only if 'v' is true */
1642 break;
1643 }
1644 case OPR_OR: {
1645 luaK_goiffalse(fs, v); /* go ahead only if 'v' is false */
1646 break;
1647 }
1648 case OPR_CONCAT: {
1649 luaK_exp2nextreg(fs, v); /* operand must be on the stack */
1650 break;
1651 }
1652 case OPR_ADD: case OPR_SUB:
1653 case OPR_MUL: case OPR_DIV: case OPR_IDIV:
1654 case OPR_MOD: case OPR_POW:
1655 case OPR_BAND: case OPR_BOR: case OPR_BXOR:
1656 case OPR_SHL: case OPR_SHR: {
1657 if (!tonumeral(v, NULL))
1658 luaK_exp2anyreg(fs, v);
1659 /* else keep numeral, which may be folded or used as an immediate
1660 operand */
1661 break;
1662 }
1663 case OPR_EQ: case OPR_NE: {
1664 if (!tonumeral(v, NULL))
1665 exp2RK(fs, v);
1666 /* else keep numeral, which may be an immediate operand */
1667 break;
1668 }
1669 case OPR_LT: case OPR_LE:
1670 case OPR_GT: case OPR_GE: {
1671 int dummy, dummy2;
1672 if (!isSCnumber(v, &dummy, &dummy2))
1673 luaK_exp2anyreg(fs, v);
1674 /* else keep numeral, which may be an immediate operand */
1675 break;
1676 }
1677 default: lua_assert(0);
1678 }
1679}
1680
1681/*
1682** Create code for '(e1 .. e2)'.
1683** For '(e1 .. e2.1 .. e2.2)' (which is '(e1 .. (e2.1 .. e2.2))',
1684** because concatenation is right associative), merge both CONCATs.
1685*/
1686static void codeconcat (FuncState *fs, expdesc *e1, expdesc *e2, int line) {
1687 Instruction *ie2 = previousinstruction(fs);
1688 if (GET_OPCODE(*ie2) == OP_CONCAT) { /* is 'e2' a concatenation? */
1689 int n = GETARG_B(*ie2); /* # of elements concatenated in 'e2' */
1690 lua_assert(e1->u.info + 1 == GETARG_A(*ie2));
1691 freeexp(fs, e2);
1692 SETARG_A(*ie2, e1->u.info); /* correct first element ('e1') */
1693 SETARG_B(*ie2, n + 1); /* will concatenate one more element */
1694 }
1695 else { /* 'e2' is not a concatenation */
1696 luaK_codeABC(fs, OP_CONCAT, e1->u.info, 2, 0); /* new concat opcode */
1697 freeexp(fs, e2);
1698 luaK_fixline(fs, line);
1699 }
1700}
1701
1702
1703/*
1704** Finalize code for binary operation, after reading 2nd operand.
1705*/
1706void luaK_posfix (FuncState *fs, BinOpr opr,
1707 expdesc *e1, expdesc *e2, int line) {
1708 luaK_dischargevars(fs, e2);
1709 if (foldbinop(opr) && constfolding(fs, opr + LUA_OPADD, e1, e2))
1710 return; /* done by folding */
1711 switch (opr) {
1712 case OPR_AND: {
1713 lua_assert(e1->t == NO_JUMP); /* list closed by 'luaK_infix' */
1714 luaK_concat(fs, &e2->f, e1->f);
1715 *e1 = *e2;
1716 break;
1717 }
1718 case OPR_OR: {
1719 lua_assert(e1->f == NO_JUMP); /* list closed by 'luaK_infix' */
1720 luaK_concat(fs, &e2->t, e1->t);
1721 *e1 = *e2;
1722 break;
1723 }
1724 case OPR_CONCAT: { /* e1 .. e2 */
1725 luaK_exp2nextreg(fs, e2);
1726 codeconcat(fs, e1, e2, line);
1727 break;
1728 }
1729 case OPR_ADD: case OPR_MUL: {
1730 codecommutative(fs, opr, e1, e2, line);
1731 break;
1732 }
1733 case OPR_SUB: {
1734 if (finishbinexpneg(fs, e1, e2, OP_ADDI, line, TM_SUB))
1735 break; /* coded as (r1 + -I) */
1736 /* ELSE */
1737 } /* FALLTHROUGH */
1738 case OPR_DIV: case OPR_IDIV: case OPR_MOD: case OPR_POW: {
1739 codearith(fs, opr, e1, e2, 0, line);
1740 break;
1741 }
1742 case OPR_BAND: case OPR_BOR: case OPR_BXOR: {
1743 codebitwise(fs, opr, e1, e2, line);
1744 break;
1745 }
1746 case OPR_SHL: {
1747 if (isSCint(e1)) {
1748 swapexps(e1, e2);
1749 codebini(fs, OP_SHLI, e1, e2, 1, line, TM_SHL); /* I << r2 */
1750 }
1751 else if (finishbinexpneg(fs, e1, e2, OP_SHRI, line, TM_SHL)) {
1752 /* coded as (r1 >> -I) */;
1753 }
1754 else /* regular case (two registers) */
1755 codebinexpval(fs, opr, e1, e2, line);
1756 break;
1757 }
1758 case OPR_SHR: {
1759 if (isSCint(e2))
1760 codebini(fs, OP_SHRI, e1, e2, 0, line, TM_SHR); /* r1 >> I */
1761 else /* regular case (two registers) */
1762 codebinexpval(fs, opr, e1, e2, line);
1763 break;
1764 }
1765 case OPR_EQ: case OPR_NE: {
1766 codeeq(fs, opr, e1, e2);
1767 break;
1768 }
1769 case OPR_GT: case OPR_GE: {
1770 /* '(a > b)' <=> '(b < a)'; '(a >= b)' <=> '(b <= a)' */
1771 swapexps(e1, e2);
1772 opr = cast(BinOpr, (opr - OPR_GT) + OPR_LT);
1773 } /* FALLTHROUGH */
1774 case OPR_LT: case OPR_LE: {
1775 codeorder(fs, opr, e1, e2);
1776 break;
1777 }
1778 default: lua_assert(0);
1779 }
1780}
1781
1782
1783/*
1784** Change line information associated with current position, by removing
1785** previous info and adding it again with new line.
1786*/
1787void luaK_fixline (FuncState *fs, int line) {
1788 removelastlineinfo(fs);
1789 savelineinfo(fs, fs->f, line);
1790}
1791
1792
1793void luaK_settablesize (FuncState *fs, int pc, int ra, int asize, int hsize) {
1794 Instruction *inst = &fs->f->code[pc];
1795 int rb = (hsize != 0) ? luaO_ceillog2(hsize) + 1 : 0; /* hash size */
1796 int extra = asize / (MAXARG_C + 1); /* higher bits of array size */
1797 int rc = asize % (MAXARG_C + 1); /* lower bits of array size */
1798 int k = (extra > 0); /* true iff needs extra argument */
1799 *inst = CREATE_ABCk(OP_NEWTABLE, ra, rb, rc, k);
1800 *(inst + 1) = CREATE_Ax(OP_EXTRAARG, extra);
1801}
1802
1803
1804/*
1805** Emit a SETLIST instruction.
1806** 'base' is register that keeps table;
1807** 'nelems' is #table plus those to be stored now;
1808** 'tostore' is number of values (in registers 'base + 1',...) to add to
1809** table (or LUA_MULTRET to add up to stack top).
1810*/
1811void luaK_setlist (FuncState *fs, int base, int nelems, int tostore) {
1812 lua_assert(tostore != 0 && tostore <= LFIELDS_PER_FLUSH);
1813 if (tostore == LUA_MULTRET)
1814 tostore = 0;
1815 if (nelems <= MAXARG_C)
1816 luaK_codeABC(fs, OP_SETLIST, base, tostore, nelems);
1817 else {
1818 int extra = nelems / (MAXARG_C + 1);
1819 nelems %= (MAXARG_C + 1);
1820 luaK_codeABCk(fs, OP_SETLIST, base, tostore, nelems, 1);
1821 codeextraarg(fs, extra);
1822 }
1823 fs->freereg = base + 1; /* free registers with list values */
1824}
1825
1826
1827/*
1828** return the final target of a jump (skipping jumps to jumps)
1829*/
1830static int finaltarget (Instruction *code, int i) {
1831 int count;
1832 for (count = 0; count < 100; count++) { /* avoid infinite loops */
1833 Instruction pc = code[i];
1834 if (GET_OPCODE(pc) != OP_JMP)
1835 break;
1836 else
1837 i += GETARG_sJ(pc) + 1;
1838 }
1839 return i;
1840}
1841
1842
1843/*
1844** Do a final pass over the code of a function, doing small peephole
1845** optimizations and adjustments.
1846*/
1847void luaK_finish (FuncState *fs) {
1848 int i;
1849 Proto *p = fs->f;
1850 for (i = 0; i < fs->pc; i++) {
1851 Instruction *pc = &p->code[i];
1852 lua_assert(i == 0 || isOT(*(pc - 1)) == isIT(*pc));
1853 switch (GET_OPCODE(*pc)) {
1854 case OP_RETURN0: case OP_RETURN1: {
1855 if (!(fs->needclose || p->is_vararg))
1856 break; /* no extra work */
1857 /* else use OP_RETURN to do the extra work */
1858 SET_OPCODE(*pc, OP_RETURN);
1859 } /* FALLTHROUGH */
1860 case OP_RETURN: case OP_TAILCALL: {
1861 if (fs->needclose)
1862 SETARG_k(*pc, 1); /* signal that it needs to close */
1863 if (p->is_vararg)
1864 SETARG_C(*pc, p->numparams + 1); /* signal that it is vararg */
1865 break;
1866 }
1867 case OP_JMP: {
1868 int target = finaltarget(p->code, i);
1869 fixjump(fs, i, target);
1870 break;
1871 }
1872 default: break;
1873 }
1874 }
1875}