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#define hasjumps(e) ((e)->t != (e)->f)
39
40
41static int codesJ (FuncState *fs, OpCode o, int sj, int k);
42
43
44
45/* semantic error */
46l_noret luaK_semerror (LexState *ls, const char *msg) {
47 ls->t.token = 0; /* remove "near <token>" from final message */
48 luaX_syntaxerror(ls, msg);
49}
50
51
52/*
53** If expression is a numeric constant, fills 'v' with its value
54** and returns 1. Otherwise, returns 0.
55*/
56static int tonumeral (const expdesc *e, TValue *v) {
57 if (hasjumps(e))
58 return 0; /* not a numeral */
59 switch (e->k) {
60 case VKINT:
61 if (v) setivalue(v, e->u.ival);
62 return 1;
63 case VKFLT:
64 if (v) setfltvalue(v, e->u.nval);
65 return 1;
66 default: return 0;
67 }
68}
69
70
71/*
72** Get the constant value from a constant expression
73*/
74static TValue *const2val (FuncState *fs, const expdesc *e) {
75 lua_assert(e->k == VCONST);
76 return &fs->ls->dyd->actvar.arr[e->u.info].k;
77}
78
79
80/*
81** If expression is a constant, fills 'v' with its value
82** and returns 1. Otherwise, returns 0.
83*/
84int luaK_exp2const (FuncState *fs, const expdesc *e, TValue *v) {
85 if (hasjumps(e))
86 return 0; /* not a constant */
87 switch (e->k) {
88 case VFALSE:
89 setbfvalue(v);
90 return 1;
91 case VTRUE:
92 setbtvalue(v);
93 return 1;
94 case VNIL:
95 setnilvalue(v);
96 return 1;
97 case VKSTR: {
98 setsvalue(fs->ls->L, v, e->u.strval);
99 return 1;
100 }
101 case VCONST: {
102 setobj(fs->ls->L, v, const2val(fs, e));
103 return 1;
104 }
105 default: return tonumeral(e, v);
106 }
107}
108
109
110/*
111** Return the previous instruction of the current code. If there
112** may be a jump target between the current instruction and the
113** previous one, return an invalid instruction (to avoid wrong
114** optimizations).
115*/
116static Instruction *previousinstruction (FuncState *fs) {
117 static const Instruction invalidinstruction = ~(Instruction)0;
118 if (fs->pc > fs->lasttarget)
119 return &fs->f->code[fs->pc - 1]; /* previous instruction */
120 else
121 return cast(Instruction*, &invalidinstruction);
122}
123
124
125/*
126** Create a OP_LOADNIL instruction, but try to optimize: if the previous
127** instruction is also OP_LOADNIL and ranges are compatible, adjust
128** range of previous instruction instead of emitting a new one. (For
129** instance, 'local a; local b' will generate a single opcode.)
130*/
131void luaK_nil (FuncState *fs, int from, int n) {
132 int l = from + n - 1; /* last register to set nil */
133 Instruction *previous = previousinstruction(fs);
134 if (GET_OPCODE(*previous) == OP_LOADNIL) { /* previous is LOADNIL? */
135 int pfrom = GETARG_A(*previous); /* get previous range */
136 int pl = pfrom + GETARG_B(*previous);
137 if ((pfrom <= from && from <= pl + 1) ||
138 (from <= pfrom && pfrom <= l + 1)) { /* can connect both? */
139 if (pfrom < from) from = pfrom; /* from = min(from, pfrom) */
140 if (pl > l) l = pl; /* l = max(l, pl) */
141 SETARG_A(*previous, from);
142 SETARG_B(*previous, l - from);
143 return;
144 } /* else go through */
145 }
146 luaK_codeABC(fs, OP_LOADNIL, from, n - 1, 0); /* else no optimization */
147}
148
149
150/*
151** Gets the destination address of a jump instruction. Used to traverse
152** a list of jumps.
153*/
154static int getjump (FuncState *fs, int pc) {
155 int offset = GETARG_sJ(fs->f->code[pc]);
156 if (offset == NO_JUMP) /* point to itself represents end of list */
157 return NO_JUMP; /* end of list */
158 else
159 return (pc+1)+offset; /* turn offset into absolute position */
160}
161
162
163/*
164** Fix jump instruction at position 'pc' to jump to 'dest'.
165** (Jump addresses are relative in Lua)
166*/
167static void fixjump (FuncState *fs, int pc, int dest) {
168 Instruction *jmp = &fs->f->code[pc];
169 int offset = dest - (pc + 1);
170 lua_assert(dest != NO_JUMP);
171 if (!(-OFFSET_sJ <= offset && offset <= MAXARG_sJ - OFFSET_sJ))
172 luaX_syntaxerror(fs->ls, "control structure too long");
173 lua_assert(GET_OPCODE(*jmp) == OP_JMP);
174 SETARG_sJ(*jmp, offset);
175}
176
177
178/*
179** Concatenate jump-list 'l2' into jump-list 'l1'
180*/
181void luaK_concat (FuncState *fs, int *l1, int l2) {
182 if (l2 == NO_JUMP) return; /* nothing to concatenate? */
183 else if (*l1 == NO_JUMP) /* no original list? */
184 *l1 = l2; /* 'l1' points to 'l2' */
185 else {
186 int list = *l1;
187 int next;
188 while ((next = getjump(fs, list)) != NO_JUMP) /* find last element */
189 list = next;
190 fixjump(fs, list, l2); /* last element links to 'l2' */
191 }
192}
193
194
195/*
196** Create a jump instruction and return its position, so its destination
197** can be fixed later (with 'fixjump').
198*/
199int luaK_jump (FuncState *fs) {
200 return codesJ(fs, OP_JMP, NO_JUMP, 0);
201}
202
203
204/*
205** Code a 'return' instruction
206*/
207void luaK_ret (FuncState *fs, int first, int nret) {
208 OpCode op;
209 switch (nret) {
210 case 0: op = OP_RETURN0; break;
211 case 1: op = OP_RETURN1; break;
212 default: op = OP_RETURN; break;
213 }
214 luaK_codeABC(fs, op, first, nret + 1, 0);
215}
216
217
218/*
219** Code a "conditional jump", that is, a test or comparison opcode
220** followed by a jump. Return jump position.
221*/
222static int condjump (FuncState *fs, OpCode op, int A, int B, int C, int k) {
223 luaK_codeABCk(fs, op, A, B, C, k);
224 return luaK_jump(fs);
225}
226
227
228/*
229** returns current 'pc' and marks it as a jump target (to avoid wrong
230** optimizations with consecutive instructions not in the same basic block).
231*/
232int luaK_getlabel (FuncState *fs) {
233 fs->lasttarget = fs->pc;
234 return fs->pc;
235}
236
237
238/*
239** Returns the position of the instruction "controlling" a given
240** jump (that is, its condition), or the jump itself if it is
241** unconditional.
242*/
243static Instruction *getjumpcontrol (FuncState *fs, int pc) {
244 Instruction *pi = &fs->f->code[pc];
245 if (pc >= 1 && testTMode(GET_OPCODE(*(pi-1))))
246 return pi-1;
247 else
248 return pi;
249}
250
251
252/*
253** Patch destination register for a TESTSET instruction.
254** If instruction in position 'node' is not a TESTSET, return 0 ("fails").
255** Otherwise, if 'reg' is not 'NO_REG', set it as the destination
256** register. Otherwise, change instruction to a simple 'TEST' (produces
257** no register value)
258*/
259static int patchtestreg (FuncState *fs, int node, int reg) {
260 Instruction *i = getjumpcontrol(fs, node);
261 if (GET_OPCODE(*i) != OP_TESTSET)
262 return 0; /* cannot patch other instructions */
263 if (reg != NO_REG && reg != GETARG_B(*i))
264 SETARG_A(*i, reg);
265 else {
266 /* no register to put value or register already has the value;
267 change instruction to simple test */
268 *i = CREATE_ABCk(OP_TEST, GETARG_B(*i), 0, 0, GETARG_k(*i));
269 }
270 return 1;
271}
272
273
274/*
275** Traverse a list of tests ensuring no one produces a value
276*/
277static void removevalues (FuncState *fs, int list) {
278 for (; list != NO_JUMP; list = getjump(fs, list))
279 patchtestreg(fs, list, NO_REG);
280}
281
282
283/*
284** Traverse a list of tests, patching their destination address and
285** registers: tests producing values jump to 'vtarget' (and put their
286** values in 'reg'), other tests jump to 'dtarget'.
287*/
288static void patchlistaux (FuncState *fs, int list, int vtarget, int reg,
289 int dtarget) {
290 while (list != NO_JUMP) {
291 int next = getjump(fs, list);
292 if (patchtestreg(fs, list, reg))
293 fixjump(fs, list, vtarget);
294 else
295 fixjump(fs, list, dtarget); /* jump to default target */
296 list = next;
297 }
298}
299
300
301/*
302** Path all jumps in 'list' to jump to 'target'.
303** (The assert means that we cannot fix a jump to a forward address
304** because we only know addresses once code is generated.)
305*/
306void luaK_patchlist (FuncState *fs, int list, int target) {
307 lua_assert(target <= fs->pc);
308 patchlistaux(fs, list, target, NO_REG, target);
309}
310
311
312void luaK_patchtohere (FuncState *fs, int list) {
313 int hr = luaK_getlabel(fs); /* mark "here" as a jump target */
314 luaK_patchlist(fs, list, hr);
315}
316
317
318/* limit for difference between lines in relative line info. */
319#define LIMLINEDIFF 0x80
320
321
322/*
323** Save line info for a new instruction. If difference from last line
324** does not fit in a byte, of after that many instructions, save a new
325** absolute line info; (in that case, the special value 'ABSLINEINFO'
326** in 'lineinfo' signals the existence of this absolute information.)
327** Otherwise, store the difference from last line in 'lineinfo'.
328*/
329static void savelineinfo (FuncState *fs, Proto *f, int line) {
330 int linedif = line - fs->previousline;
331 int pc = fs->pc - 1; /* last instruction coded */
332 if (abs(linedif) >= LIMLINEDIFF || fs->iwthabs++ >= MAXIWTHABS) {
333 luaM_growvector(fs->ls->L, f->abslineinfo, fs->nabslineinfo,
334 f->sizeabslineinfo, AbsLineInfo, MAX_INT, "lines");
335 f->abslineinfo[fs->nabslineinfo].pc = pc;
336 f->abslineinfo[fs->nabslineinfo++].line = line;
337 linedif = ABSLINEINFO; /* signal that there is absolute information */
338 fs->iwthabs = 1; /* restart counter */
339 }
340 luaM_growvector(fs->ls->L, f->lineinfo, pc, f->sizelineinfo, ls_byte,
341 MAX_INT, "opcodes");
342 f->lineinfo[pc] = linedif;
343 fs->previousline = line; /* last line saved */
344}
345
346
347/*
348** Remove line information from the last instruction.
349** If line information for that instruction is absolute, set 'iwthabs'
350** above its max to force the new (replacing) instruction to have
351** absolute line info, too.
352*/
353static void removelastlineinfo (FuncState *fs) {
354 Proto *f = fs->f;
355 int pc = fs->pc - 1; /* last instruction coded */
356 if (f->lineinfo[pc] != ABSLINEINFO) { /* relative line info? */
357 fs->previousline -= f->lineinfo[pc]; /* correct last line saved */
358 fs->iwthabs--; /* undo previous increment */
359 }
360 else { /* absolute line information */
361 lua_assert(f->abslineinfo[fs->nabslineinfo - 1].pc == pc);
362 fs->nabslineinfo--; /* remove it */
363 fs->iwthabs = MAXIWTHABS + 1; /* force next line info to be absolute */
364 }
365}
366
367
368/*
369** Remove the last instruction created, correcting line information
370** accordingly.
371*/
372static void removelastinstruction (FuncState *fs) {
373 removelastlineinfo(fs);
374 fs->pc--;
375}
376
377
378/*
379** Emit instruction 'i', checking for array sizes and saving also its
380** line information. Return 'i' position.
381*/
382int luaK_code (FuncState *fs, Instruction i) {
383 Proto *f = fs->f;
384 /* put new instruction in code array */
385 luaM_growvector(fs->ls->L, f->code, fs->pc, f->sizecode, Instruction,
386 MAX_INT, "opcodes");
387 f->code[fs->pc++] = i;
388 savelineinfo(fs, f, fs->ls->lastline);
389 return fs->pc - 1; /* index of new instruction */
390}
391
392
393/*
394** Format and emit an 'iABC' instruction. (Assertions check consistency
395** of parameters versus opcode.)
396*/
397int luaK_codeABCk (FuncState *fs, OpCode o, int a, int b, int c, int k) {
398 lua_assert(getOpMode(o) == iABC);
399 lua_assert(a <= MAXARG_A && b <= MAXARG_B &&
400 c <= MAXARG_C && (k & ~1) == 0);
401 return luaK_code(fs, CREATE_ABCk(o, a, b, c, k));
402}
403
404
405/*
406** Format and emit an 'iABx' instruction.
407*/
408int luaK_codeABx (FuncState *fs, OpCode o, int a, unsigned int bc) {
409 lua_assert(getOpMode(o) == iABx);
410 lua_assert(a <= MAXARG_A && bc <= MAXARG_Bx);
411 return luaK_code(fs, CREATE_ABx(o, a, bc));
412}
413
414
415/*
416** Format and emit an 'iAsBx' instruction.
417*/
418int luaK_codeAsBx (FuncState *fs, OpCode o, int a, int bc) {
419 unsigned int b = bc + OFFSET_sBx;
420 lua_assert(getOpMode(o) == iAsBx);
421 lua_assert(a <= MAXARG_A && b <= MAXARG_Bx);
422 return luaK_code(fs, CREATE_ABx(o, a, b));
423}
424
425
426/*
427** Format and emit an 'isJ' instruction.
428*/
429static int codesJ (FuncState *fs, OpCode o, int sj, int k) {
430 unsigned int j = sj + OFFSET_sJ;
431 lua_assert(getOpMode(o) == isJ);
432 lua_assert(j <= MAXARG_sJ && (k & ~1) == 0);
433 return luaK_code(fs, CREATE_sJ(o, j, k));
434}
435
436
437/*
438** Emit an "extra argument" instruction (format 'iAx')
439*/
440static int codeextraarg (FuncState *fs, int a) {
441 lua_assert(a <= MAXARG_Ax);
442 return luaK_code(fs, CREATE_Ax(OP_EXTRAARG, a));
443}
444
445
446/*
447** Emit a "load constant" instruction, using either 'OP_LOADK'
448** (if constant index 'k' fits in 18 bits) or an 'OP_LOADKX'
449** instruction with "extra argument".
450*/
451static int luaK_codek (FuncState *fs, int reg, int k) {
452 if (k <= MAXARG_Bx)
453 return luaK_codeABx(fs, OP_LOADK, reg, k);
454 else {
455 int p = luaK_codeABx(fs, OP_LOADKX, reg, 0);
456 codeextraarg(fs, k);
457 return p;
458 }
459}
460
461
462/*
463** Check register-stack level, keeping track of its maximum size
464** in field 'maxstacksize'
465*/
466void luaK_checkstack (FuncState *fs, int n) {
467 int newstack = fs->freereg + n;
468 if (newstack > fs->f->maxstacksize) {
469 if (newstack >= MAXREGS)
470 luaX_syntaxerror(fs->ls,
471 "function or expression needs too many registers");
472 fs->f->maxstacksize = cast_byte(newstack);
473 }
474}
475
476
477/*
478** Reserve 'n' registers in register stack
479*/
480void luaK_reserveregs (FuncState *fs, int n) {
481 luaK_checkstack(fs, n);
482 fs->freereg += n;
483}
484
485
486/*
487** Free register 'reg', if it is neither a constant index nor
488** a local variable.
489)
490*/
491static void freereg (FuncState *fs, int reg) {
492 if (reg >= luaY_nvarstack(fs)) {
493 fs->freereg--;
494 lua_assert(reg == fs->freereg);
495 }
496}
497
498
499/*
500** Free two registers in proper order
501*/
502static void freeregs (FuncState *fs, int r1, int r2) {
503 if (r1 > r2) {
504 freereg(fs, r1);
505 freereg(fs, r2);
506 }
507 else {
508 freereg(fs, r2);
509 freereg(fs, r1);
510 }
511}
512
513
514/*
515** Free register used by expression 'e' (if any)
516*/
517static void freeexp (FuncState *fs, expdesc *e) {
518 if (e->k == VNONRELOC)
519 freereg(fs, e->u.info);
520}
521
522
523/*
524** Free registers used by expressions 'e1' and 'e2' (if any) in proper
525** order.
526*/
527static void freeexps (FuncState *fs, expdesc *e1, expdesc *e2) {
528 int r1 = (e1->k == VNONRELOC) ? e1->u.info : -1;
529 int r2 = (e2->k == VNONRELOC) ? e2->u.info : -1;
530 freeregs(fs, r1, r2);
531}
532
533
534/*
535** Add constant 'v' to prototype's list of constants (field 'k').
536** Use scanner's table to cache position of constants in constant list
537** and try to reuse constants. Because some values should not be used
538** as keys (nil cannot be a key, integer keys can collapse with float
539** keys), the caller must provide a useful 'key' for indexing the cache.
540** Note that all functions share the same table, so entering or exiting
541** a function can make some indices wrong.
542*/
543static int addk (FuncState *fs, TValue *key, TValue *v) {
544 TValue val;
545 lua_State *L = fs->ls->L;
546 Proto *f = fs->f;
547 const TValue *idx = luaH_get(fs->ls->h, key); /* query scanner table */
548 int k, oldsize;
549 if (ttisinteger(idx)) { /* is there an index there? */
550 k = cast_int(ivalue(idx));
551 /* correct value? (warning: must distinguish floats from integers!) */
552 if (k < fs->nk && ttypetag(&f->k[k]) == ttypetag(v) &&
553 luaV_rawequalobj(&f->k[k], v))
554 return k; /* reuse index */
555 }
556 /* constant not found; create a new entry */
557 oldsize = f->sizek;
558 k = fs->nk;
559 /* numerical value does not need GC barrier;
560 table has no metatable, so it does not need to invalidate cache */
561 setivalue(&val, k);
562 luaH_finishset(L, fs->ls->h, key, idx, &val);
563 luaM_growvector(L, f->k, k, f->sizek, TValue, MAXARG_Ax, "constants");
564 while (oldsize < f->sizek) setnilvalue(&f->k[oldsize++]);
565 setobj(L, &f->k[k], v);
566 fs->nk++;
567 luaC_barrier(L, f, v);
568 return k;
569}
570
571
572/*
573** Add a string to list of constants and return its index.
574*/
575static int stringK (FuncState *fs, TString *s) {
576 TValue o;
577 setsvalue(fs->ls->L, &o, s);
578 return addk(fs, &o, &o); /* use string itself as key */
579}
580
581
582/*
583** Add an integer to list of constants and return its index.
584*/
585static int luaK_intK (FuncState *fs, lua_Integer n) {
586 TValue o;
587 setivalue(&o, n);
588 return addk(fs, &o, &o); /* use integer itself as key */
589}
590
591/*
592** Add a float to list of constants and return its index. Floats
593** with integral values need a different key, to avoid collision
594** with actual integers. To that, we add to the number its smaller
595** power-of-two fraction that is still significant in its scale.
596** For doubles, that would be 1/2^52.
597** (This method is not bulletproof: there may be another float
598** with that value, and for floats larger than 2^53 the result is
599** still an integer. At worst, this only wastes an entry with
600** a duplicate.)
601*/
602static int luaK_numberK (FuncState *fs, lua_Number r) {
603 TValue o;
604 lua_Integer ik;
605 setfltvalue(&o, r);
606 if (!luaV_flttointeger(r, &ik, F2Ieq)) /* not an integral value? */
607 return addk(fs, &o, &o); /* use number itself as key */
608 else { /* must build an alternative key */
609 const int nbm = l_floatatt(MANT_DIG);
610 const lua_Number q = l_mathop(ldexp)(l_mathop(1.0), -nbm + 1);
611 const lua_Number k = (ik == 0) ? q : r + r*q; /* new key */
612 TValue kv;
613 setfltvalue(&kv, k);
614 /* result is not an integral value, unless value is too large */
615 lua_assert(!luaV_flttointeger(k, &ik, F2Ieq) ||
616 l_mathop(fabs)(r) >= l_mathop(1e6));
617 return addk(fs, &kv, &o);
618 }
619}
620
621
622/*
623** Add a false to list of constants and return its index.
624*/
625static int boolF (FuncState *fs) {
626 TValue o;
627 setbfvalue(&o);
628 return addk(fs, &o, &o); /* use boolean itself as key */
629}
630
631
632/*
633** Add a true to list of constants and return its index.
634*/
635static int boolT (FuncState *fs) {
636 TValue o;
637 setbtvalue(&o);
638 return addk(fs, &o, &o); /* use boolean itself as key */
639}
640
641
642/*
643** Add nil to list of constants and return its index.
644*/
645static int nilK (FuncState *fs) {
646 TValue k, v;
647 setnilvalue(&v);
648 /* cannot use nil as key; instead use table itself to represent nil */
649 sethvalue(fs->ls->L, &k, fs->ls->h);
650 return addk(fs, &k, &v);
651}
652
653
654/*
655** Check whether 'i' can be stored in an 'sC' operand. Equivalent to
656** (0 <= int2sC(i) && int2sC(i) <= MAXARG_C) but without risk of
657** overflows in the hidden addition inside 'int2sC'.
658*/
659static int fitsC (lua_Integer i) {
660 return (l_castS2U(i) + OFFSET_sC <= cast_uint(MAXARG_C));
661}
662
663
664/*
665** Check whether 'i' can be stored in an 'sBx' operand.
666*/
667static int fitsBx (lua_Integer i) {
668 return (-OFFSET_sBx <= i && i <= MAXARG_Bx - OFFSET_sBx);
669}
670
671
672void luaK_int (FuncState *fs, int reg, lua_Integer i) {
673 if (fitsBx(i))
674 luaK_codeAsBx(fs, OP_LOADI, reg, cast_int(i));
675 else
676 luaK_codek(fs, reg, luaK_intK(fs, i));
677}
678
679
680static void luaK_float (FuncState *fs, int reg, lua_Number f) {
681 lua_Integer fi;
682 if (luaV_flttointeger(f, &fi, F2Ieq) && fitsBx(fi))
683 luaK_codeAsBx(fs, OP_LOADF, reg, cast_int(fi));
684 else
685 luaK_codek(fs, reg, luaK_numberK(fs, f));
686}
687
688
689/*
690** Convert a constant in 'v' into an expression description 'e'
691*/
692static void const2exp (TValue *v, expdesc *e) {
693 switch (ttypetag(v)) {
694 case LUA_VNUMINT:
695 e->k = VKINT; e->u.ival = ivalue(v);
696 break;
697 case LUA_VNUMFLT:
698 e->k = VKFLT; e->u.nval = fltvalue(v);
699 break;
700 case LUA_VFALSE:
701 e->k = VFALSE;
702 break;
703 case LUA_VTRUE:
704 e->k = VTRUE;
705 break;
706 case LUA_VNIL:
707 e->k = VNIL;
708 break;
709 case LUA_VSHRSTR: case LUA_VLNGSTR:
710 e->k = VKSTR; e->u.strval = tsvalue(v);
711 break;
712 default: lua_assert(0);
713 }
714}
715
716
717/*
718** Fix an expression to return the number of results 'nresults'.
719** 'e' must be a multi-ret expression (function call or vararg).
720*/
721void luaK_setreturns (FuncState *fs, expdesc *e, int nresults) {
722 Instruction *pc = &getinstruction(fs, e);
723 if (e->k == VCALL) /* expression is an open function call? */
724 SETARG_C(*pc, nresults + 1);
725 else {
726 lua_assert(e->k == VVARARG);
727 SETARG_C(*pc, nresults + 1);
728 SETARG_A(*pc, fs->freereg);
729 luaK_reserveregs(fs, 1);
730 }
731}
732
733
734/*
735** Convert a VKSTR to a VK
736*/
737static void str2K (FuncState *fs, expdesc *e) {
738 lua_assert(e->k == VKSTR);
739 e->u.info = stringK(fs, e->u.strval);
740 e->k = VK;
741}
742
743
744/*
745** Fix an expression to return one result.
746** If expression is not a multi-ret expression (function call or
747** vararg), it already returns one result, so nothing needs to be done.
748** Function calls become VNONRELOC expressions (as its result comes
749** fixed in the base register of the call), while vararg expressions
750** become VRELOC (as OP_VARARG puts its results where it wants).
751** (Calls are created returning one result, so that does not need
752** to be fixed.)
753*/
754void luaK_setoneret (FuncState *fs, expdesc *e) {
755 if (e->k == VCALL) { /* expression is an open function call? */
756 /* already returns 1 value */
757 lua_assert(GETARG_C(getinstruction(fs, e)) == 2);
758 e->k = VNONRELOC; /* result has fixed position */
759 e->u.info = GETARG_A(getinstruction(fs, e));
760 }
761 else if (e->k == VVARARG) {
762 SETARG_C(getinstruction(fs, e), 2);
763 e->k = VRELOC; /* can relocate its simple result */
764 }
765}
766
767
768/*
769** Ensure that expression 'e' is not a variable (nor a <const>).
770** (Expression still may have jump lists.)
771*/
772void luaK_dischargevars (FuncState *fs, expdesc *e) {
773 switch (e->k) {
774 case VCONST: {
775 const2exp(const2val(fs, e), e);
776 break;
777 }
778 case VLOCAL: { /* already in a register */
779 e->u.info = e->u.var.ridx;
780 e->k = VNONRELOC; /* becomes a non-relocatable value */
781 break;
782 }
783 case VUPVAL: { /* move value to some (pending) register */
784 e->u.info = luaK_codeABC(fs, OP_GETUPVAL, 0, e->u.info, 0);
785 e->k = VRELOC;
786 break;
787 }
788 case VINDEXUP: {
789 e->u.info = luaK_codeABC(fs, OP_GETTABUP, 0, e->u.ind.t, e->u.ind.idx);
790 e->k = VRELOC;
791 break;
792 }
793 case VINDEXI: {
794 freereg(fs, e->u.ind.t);
795 e->u.info = luaK_codeABC(fs, OP_GETI, 0, e->u.ind.t, e->u.ind.idx);
796 e->k = VRELOC;
797 break;
798 }
799 case VINDEXSTR: {
800 freereg(fs, e->u.ind.t);
801 e->u.info = luaK_codeABC(fs, OP_GETFIELD, 0, e->u.ind.t, e->u.ind.idx);
802 e->k = VRELOC;
803 break;
804 }
805 case VINDEXED: {
806 freeregs(fs, e->u.ind.t, e->u.ind.idx);
807 e->u.info = luaK_codeABC(fs, OP_GETTABLE, 0, e->u.ind.t, e->u.ind.idx);
808 e->k = VRELOC;
809 break;
810 }
811 case VVARARG: case VCALL: {
812 luaK_setoneret(fs, e);
813 break;
814 }
815 default: break; /* there is one value available (somewhere) */
816 }
817}
818
819
820/*
821** Ensure expression value is in register 'reg', making 'e' a
822** non-relocatable expression.
823** (Expression still may have jump lists.)
824*/
825static void discharge2reg (FuncState *fs, expdesc *e, int reg) {
826 luaK_dischargevars(fs, e);
827 switch (e->k) {
828 case VNIL: {
829 luaK_nil(fs, reg, 1);
830 break;
831 }
832 case VFALSE: {
833 luaK_codeABC(fs, OP_LOADFALSE, reg, 0, 0);
834 break;
835 }
836 case VTRUE: {
837 luaK_codeABC(fs, OP_LOADTRUE, reg, 0, 0);
838 break;
839 }
840 case VKSTR: {
841 str2K(fs, e);
842 } /* FALLTHROUGH */
843 case VK: {
844 luaK_codek(fs, reg, e->u.info);
845 break;
846 }
847 case VKFLT: {
848 luaK_float(fs, reg, e->u.nval);
849 break;
850 }
851 case VKINT: {
852 luaK_int(fs, reg, e->u.ival);
853 break;
854 }
855 case VRELOC: {
856 Instruction *pc = &getinstruction(fs, e);
857 SETARG_A(*pc, reg); /* instruction will put result in 'reg' */
858 break;
859 }
860 case VNONRELOC: {
861 if (reg != e->u.info)
862 luaK_codeABC(fs, OP_MOVE, reg, e->u.info, 0);
863 break;
864 }
865 default: {
866 lua_assert(e->k == VJMP);
867 return; /* nothing to do... */
868 }
869 }
870 e->u.info = reg;
871 e->k = VNONRELOC;
872}
873
874
875/*
876** Ensure expression value is in a register, making 'e' a
877** non-relocatable expression.
878** (Expression still may have jump lists.)
879*/
880static void discharge2anyreg (FuncState *fs, expdesc *e) {
881 if (e->k != VNONRELOC) { /* no fixed register yet? */
882 luaK_reserveregs(fs, 1); /* get a register */
883 discharge2reg(fs, e, fs->freereg-1); /* put value there */
884 }
885}
886
887
888static int code_loadbool (FuncState *fs, int A, OpCode op) {
889 luaK_getlabel(fs); /* those instructions may be jump targets */
890 return luaK_codeABC(fs, op, A, 0, 0);
891}
892
893
894/*
895** check whether list has any jump that do not produce a value
896** or produce an inverted value
897*/
898static int need_value (FuncState *fs, int list) {
899 for (; list != NO_JUMP; list = getjump(fs, list)) {
900 Instruction i = *getjumpcontrol(fs, list);
901 if (GET_OPCODE(i) != OP_TESTSET) return 1;
902 }
903 return 0; /* not found */
904}
905
906
907/*
908** Ensures final expression result (which includes results from its
909** jump lists) is in register 'reg'.
910** If expression has jumps, need to patch these jumps either to
911** its final position or to "load" instructions (for those tests
912** that do not produce values).
913*/
914static void exp2reg (FuncState *fs, expdesc *e, int reg) {
915 discharge2reg(fs, e, reg);
916 if (e->k == VJMP) /* expression itself is a test? */
917 luaK_concat(fs, &e->t, e->u.info); /* put this jump in 't' list */
918 if (hasjumps(e)) {
919 int final; /* position after whole expression */
920 int p_f = NO_JUMP; /* position of an eventual LOAD false */
921 int p_t = NO_JUMP; /* position of an eventual LOAD true */
922 if (need_value(fs, e->t) || need_value(fs, e->f)) {
923 int fj = (e->k == VJMP) ? NO_JUMP : luaK_jump(fs);
924 p_f = code_loadbool(fs, reg, OP_LFALSESKIP); /* skip next inst. */
925 p_t = code_loadbool(fs, reg, OP_LOADTRUE);
926 /* jump around these booleans if 'e' is not a test */
927 luaK_patchtohere(fs, fj);
928 }
929 final = luaK_getlabel(fs);
930 patchlistaux(fs, e->f, final, reg, p_f);
931 patchlistaux(fs, e->t, final, reg, p_t);
932 }
933 e->f = e->t = NO_JUMP;
934 e->u.info = reg;
935 e->k = VNONRELOC;
936}
937
938
939/*
940** Ensures final expression result is in next available register.
941*/
942void luaK_exp2nextreg (FuncState *fs, expdesc *e) {
943 luaK_dischargevars(fs, e);
944 freeexp(fs, e);
945 luaK_reserveregs(fs, 1);
946 exp2reg(fs, e, fs->freereg - 1);
947}
948
949
950/*
951** Ensures final expression result is in some (any) register
952** and return that register.
953*/
954int luaK_exp2anyreg (FuncState *fs, expdesc *e) {
955 luaK_dischargevars(fs, e);
956 if (e->k == VNONRELOC) { /* expression already has a register? */
957 if (!hasjumps(e)) /* no jumps? */
958 return e->u.info; /* result is already in a register */
959 if (e->u.info >= luaY_nvarstack(fs)) { /* reg. is not a local? */
960 exp2reg(fs, e, e->u.info); /* put final result in it */
961 return e->u.info;
962 }
963 /* else expression has jumps and cannot change its register
964 to hold the jump values, because it is a local variable.
965 Go through to the default case. */
966 }
967 luaK_exp2nextreg(fs, e); /* default: use next available register */
968 return e->u.info;
969}
970
971
972/*
973** Ensures final expression result is either in a register
974** or in an upvalue.
975*/
976void luaK_exp2anyregup (FuncState *fs, expdesc *e) {
977 if (e->k != VUPVAL || hasjumps(e))
978 luaK_exp2anyreg(fs, e);
979}
980
981
982/*
983** Ensures final expression result is either in a register
984** or it is a constant.
985*/
986void luaK_exp2val (FuncState *fs, expdesc *e) {
987 if (hasjumps(e))
988 luaK_exp2anyreg(fs, e);
989 else
990 luaK_dischargevars(fs, e);
991}
992
993
994/*
995** Try to make 'e' a K expression with an index in the range of R/K
996** indices. Return true iff succeeded.
997*/
998static int luaK_exp2K (FuncState *fs, expdesc *e) {
999 if (!hasjumps(e)) {
1000 int info;
1001 switch (e->k) { /* move constants to 'k' */
1002 case VTRUE: info = boolT(fs); break;
1003 case VFALSE: info = boolF(fs); break;
1004 case VNIL: info = nilK(fs); break;
1005 case VKINT: info = luaK_intK(fs, e->u.ival); break;
1006 case VKFLT: info = luaK_numberK(fs, e->u.nval); break;
1007 case VKSTR: info = stringK(fs, e->u.strval); break;
1008 case VK: info = e->u.info; break;
1009 default: return 0; /* not a constant */
1010 }
1011 if (info <= MAXINDEXRK) { /* does constant fit in 'argC'? */
1012 e->k = VK; /* make expression a 'K' expression */
1013 e->u.info = info;
1014 return 1;
1015 }
1016 }
1017 /* else, expression doesn't fit; leave it unchanged */
1018 return 0;
1019}
1020
1021
1022/*
1023** Ensures final expression result is in a valid R/K index
1024** (that is, it is either in a register or in 'k' with an index
1025** in the range of R/K indices).
1026** Returns 1 iff expression is K.
1027*/
1028int luaK_exp2RK (FuncState *fs, expdesc *e) {
1029 if (luaK_exp2K(fs, e))
1030 return 1;
1031 else { /* not a constant in the right range: put it in a register */
1032 luaK_exp2anyreg(fs, e);
1033 return 0;
1034 }
1035}
1036
1037
1038static void codeABRK (FuncState *fs, OpCode o, int a, int b,
1039 expdesc *ec) {
1040 int k = luaK_exp2RK(fs, ec);
1041 luaK_codeABCk(fs, o, a, b, ec->u.info, k);
1042}
1043
1044
1045/*
1046** Generate code to store result of expression 'ex' into variable 'var'.
1047*/
1048void luaK_storevar (FuncState *fs, expdesc *var, expdesc *ex) {
1049 switch (var->k) {
1050 case VLOCAL: {
1051 freeexp(fs, ex);
1052 exp2reg(fs, ex, var->u.var.ridx); /* compute 'ex' into proper place */
1053 return;
1054 }
1055 case VUPVAL: {
1056 int e = luaK_exp2anyreg(fs, ex);
1057 luaK_codeABC(fs, OP_SETUPVAL, e, var->u.info, 0);
1058 break;
1059 }
1060 case VINDEXUP: {
1061 codeABRK(fs, OP_SETTABUP, var->u.ind.t, var->u.ind.idx, ex);
1062 break;
1063 }
1064 case VINDEXI: {
1065 codeABRK(fs, OP_SETI, var->u.ind.t, var->u.ind.idx, ex);
1066 break;
1067 }
1068 case VINDEXSTR: {
1069 codeABRK(fs, OP_SETFIELD, var->u.ind.t, var->u.ind.idx, ex);
1070 break;
1071 }
1072 case VINDEXED: {
1073 codeABRK(fs, OP_SETTABLE, var->u.ind.t, var->u.ind.idx, ex);
1074 break;
1075 }
1076 default: lua_assert(0); /* invalid var kind to store */
1077 }
1078 freeexp(fs, ex);
1079}
1080
1081
1082/*
1083** Emit SELF instruction (convert expression 'e' into 'e:key(e,').
1084*/
1085void luaK_self (FuncState *fs, expdesc *e, expdesc *key) {
1086 int ereg;
1087 luaK_exp2anyreg(fs, e);
1088 ereg = e->u.info; /* register where 'e' was placed */
1089 freeexp(fs, e);
1090 e->u.info = fs->freereg; /* base register for op_self */
1091 e->k = VNONRELOC; /* self expression has a fixed register */
1092 luaK_reserveregs(fs, 2); /* function and 'self' produced by op_self */
1093 codeABRK(fs, OP_SELF, e->u.info, ereg, key);
1094 freeexp(fs, key);
1095}
1096
1097
1098/*
1099** Negate condition 'e' (where 'e' is a comparison).
1100*/
1101static void negatecondition (FuncState *fs, expdesc *e) {
1102 Instruction *pc = getjumpcontrol(fs, e->u.info);
1103 lua_assert(testTMode(GET_OPCODE(*pc)) && GET_OPCODE(*pc) != OP_TESTSET &&
1104 GET_OPCODE(*pc) != OP_TEST);
1105 SETARG_k(*pc, (GETARG_k(*pc) ^ 1));
1106}
1107
1108
1109/*
1110** Emit instruction to jump if 'e' is 'cond' (that is, if 'cond'
1111** is true, code will jump if 'e' is true.) Return jump position.
1112** Optimize when 'e' is 'not' something, inverting the condition
1113** and removing the 'not'.
1114*/
1115static int jumponcond (FuncState *fs, expdesc *e, int cond) {
1116 if (e->k == VRELOC) {
1117 Instruction ie = getinstruction(fs, e);
1118 if (GET_OPCODE(ie) == OP_NOT) {
1119 removelastinstruction(fs); /* remove previous OP_NOT */
1120 return condjump(fs, OP_TEST, GETARG_B(ie), 0, 0, !cond);
1121 }
1122 /* else go through */
1123 }
1124 discharge2anyreg(fs, e);
1125 freeexp(fs, e);
1126 return condjump(fs, OP_TESTSET, NO_REG, e->u.info, 0, cond);
1127}
1128
1129
1130/*
1131** Emit code to go through if 'e' is true, jump otherwise.
1132*/
1133void luaK_goiftrue (FuncState *fs, expdesc *e) {
1134 int pc; /* pc of new jump */
1135 luaK_dischargevars(fs, e);
1136 switch (e->k) {
1137 case VJMP: { /* condition? */
1138 negatecondition(fs, e); /* jump when it is false */
1139 pc = e->u.info; /* save jump position */
1140 break;
1141 }
1142 case VK: case VKFLT: case VKINT: case VKSTR: case VTRUE: {
1143 pc = NO_JUMP; /* always true; do nothing */
1144 break;
1145 }
1146 default: {
1147 pc = jumponcond(fs, e, 0); /* jump when false */
1148 break;
1149 }
1150 }
1151 luaK_concat(fs, &e->f, pc); /* insert new jump in false list */
1152 luaK_patchtohere(fs, e->t); /* true list jumps to here (to go through) */
1153 e->t = NO_JUMP;
1154}
1155
1156
1157/*
1158** Emit code to go through if 'e' is false, jump otherwise.
1159*/
1160void luaK_goiffalse (FuncState *fs, expdesc *e) {
1161 int pc; /* pc of new jump */
1162 luaK_dischargevars(fs, e);
1163 switch (e->k) {
1164 case VJMP: {
1165 pc = e->u.info; /* already jump if true */
1166 break;
1167 }
1168 case VNIL: case VFALSE: {
1169 pc = NO_JUMP; /* always false; do nothing */
1170 break;
1171 }
1172 default: {
1173 pc = jumponcond(fs, e, 1); /* jump if true */
1174 break;
1175 }
1176 }
1177 luaK_concat(fs, &e->t, pc); /* insert new jump in 't' list */
1178 luaK_patchtohere(fs, e->f); /* false list jumps to here (to go through) */
1179 e->f = NO_JUMP;
1180}
1181
1182
1183/*
1184** Code 'not e', doing constant folding.
1185*/
1186static void codenot (FuncState *fs, expdesc *e) {
1187 switch (e->k) {
1188 case VNIL: case VFALSE: {
1189 e->k = VTRUE; /* true == not nil == not false */
1190 break;
1191 }
1192 case VK: case VKFLT: case VKINT: case VKSTR: case VTRUE: {
1193 e->k = VFALSE; /* false == not "x" == not 0.5 == not 1 == not true */
1194 break;
1195 }
1196 case VJMP: {
1197 negatecondition(fs, e);
1198 break;
1199 }
1200 case VRELOC:
1201 case VNONRELOC: {
1202 discharge2anyreg(fs, e);
1203 freeexp(fs, e);
1204 e->u.info = luaK_codeABC(fs, OP_NOT, 0, e->u.info, 0);
1205 e->k = VRELOC;
1206 break;
1207 }
1208 default: lua_assert(0); /* cannot happen */
1209 }
1210 /* interchange true and false lists */
1211 { int temp = e->f; e->f = e->t; e->t = temp; }
1212 removevalues(fs, e->f); /* values are useless when negated */
1213 removevalues(fs, e->t);
1214}
1215
1216
1217/*
1218** Check whether expression 'e' is a small literal string
1219*/
1220static int isKstr (FuncState *fs, expdesc *e) {
1221 return (e->k == VK && !hasjumps(e) && e->u.info <= MAXARG_B &&
1222 ttisshrstring(&fs->f->k[e->u.info]));
1223}
1224
1225/*
1226** Check whether expression 'e' is a literal integer.
1227*/
1228int luaK_isKint (expdesc *e) {
1229 return (e->k == VKINT && !hasjumps(e));
1230}
1231
1232
1233/*
1234** Check whether expression 'e' is a literal integer in
1235** proper range to fit in register C
1236*/
1237static int isCint (expdesc *e) {
1238 return luaK_isKint(e) && (l_castS2U(e->u.ival) <= l_castS2U(MAXARG_C));
1239}
1240
1241
1242/*
1243** Check whether expression 'e' is a literal integer in
1244** proper range to fit in register sC
1245*/
1246static int isSCint (expdesc *e) {
1247 return luaK_isKint(e) && fitsC(e->u.ival);
1248}
1249
1250
1251/*
1252** Check whether expression 'e' is a literal integer or float in
1253** proper range to fit in a register (sB or sC).
1254*/
1255static int isSCnumber (expdesc *e, int *pi, int *isfloat) {
1256 lua_Integer i;
1257 if (e->k == VKINT)
1258 i = e->u.ival;
1259 else if (e->k == VKFLT && luaV_flttointeger(e->u.nval, &i, F2Ieq))
1260 *isfloat = 1;
1261 else
1262 return 0; /* not a number */
1263 if (!hasjumps(e) && fitsC(i)) {
1264 *pi = int2sC(cast_int(i));
1265 return 1;
1266 }
1267 else
1268 return 0;
1269}
1270
1271
1272/*
1273** Create expression 't[k]'. 't' must have its final result already in a
1274** register or upvalue. Upvalues can only be indexed by literal strings.
1275** Keys can be literal strings in the constant table or arbitrary
1276** values in registers.
1277*/
1278void luaK_indexed (FuncState *fs, expdesc *t, expdesc *k) {
1279 if (k->k == VKSTR)
1280 str2K(fs, k);
1281 lua_assert(!hasjumps(t) &&
1282 (t->k == VLOCAL || t->k == VNONRELOC || t->k == VUPVAL));
1283 if (t->k == VUPVAL && !isKstr(fs, k)) /* upvalue indexed by non 'Kstr'? */
1284 luaK_exp2anyreg(fs, t); /* put it in a register */
1285 if (t->k == VUPVAL) {
1286 t->u.ind.t = t->u.info; /* upvalue index */
1287 t->u.ind.idx = k->u.info; /* literal string */
1288 t->k = VINDEXUP;
1289 }
1290 else {
1291 /* register index of the table */
1292 t->u.ind.t = (t->k == VLOCAL) ? t->u.var.ridx: t->u.info;
1293 if (isKstr(fs, k)) {
1294 t->u.ind.idx = k->u.info; /* literal string */
1295 t->k = VINDEXSTR;
1296 }
1297 else if (isCint(k)) {
1298 t->u.ind.idx = cast_int(k->u.ival); /* int. constant in proper range */
1299 t->k = VINDEXI;
1300 }
1301 else {
1302 t->u.ind.idx = luaK_exp2anyreg(fs, k); /* register */
1303 t->k = VINDEXED;
1304 }
1305 }
1306}
1307
1308
1309/*
1310** Return false if folding can raise an error.
1311** Bitwise operations need operands convertible to integers; division
1312** operations cannot have 0 as divisor.
1313*/
1314static int validop (int op, TValue *v1, TValue *v2) {
1315 switch (op) {
1316 case LUA_OPBAND: case LUA_OPBOR: case LUA_OPBXOR:
1317 case LUA_OPSHL: case LUA_OPSHR: case LUA_OPBNOT: { /* conversion errors */
1318 lua_Integer i;
1319 return (luaV_tointegerns(v1, &i, LUA_FLOORN2I) &&
1320 luaV_tointegerns(v2, &i, LUA_FLOORN2I));
1321 }
1322 case LUA_OPDIV: case LUA_OPIDIV: case LUA_OPMOD: /* division by 0 */
1323 return (nvalue(v2) != 0);
1324 default: return 1; /* everything else is valid */
1325 }
1326}
1327
1328
1329/*
1330** Try to "constant-fold" an operation; return 1 iff successful.
1331** (In this case, 'e1' has the final result.)
1332*/
1333static int constfolding (FuncState *fs, int op, expdesc *e1,
1334 const expdesc *e2) {
1335 TValue v1, v2, res;
1336 if (!tonumeral(e1, &v1) || !tonumeral(e2, &v2) || !validop(op, &v1, &v2))
1337 return 0; /* non-numeric operands or not safe to fold */
1338 luaO_rawarith(fs->ls->L, op, &v1, &v2, &res); /* does operation */
1339 if (ttisinteger(&res)) {
1340 e1->k = VKINT;
1341 e1->u.ival = ivalue(&res);
1342 }
1343 else { /* folds neither NaN nor 0.0 (to avoid problems with -0.0) */
1344 lua_Number n = fltvalue(&res);
1345 if (luai_numisnan(n) || n == 0)
1346 return 0;
1347 e1->k = VKFLT;
1348 e1->u.nval = n;
1349 }
1350 return 1;
1351}
1352
1353
1354/*
1355** Emit code for unary expressions that "produce values"
1356** (everything but 'not').
1357** Expression to produce final result will be encoded in 'e'.
1358*/
1359static void codeunexpval (FuncState *fs, OpCode op, expdesc *e, int line) {
1360 int r = luaK_exp2anyreg(fs, e); /* opcodes operate only on registers */
1361 freeexp(fs, e);
1362 e->u.info = luaK_codeABC(fs, op, 0, r, 0); /* generate opcode */
1363 e->k = VRELOC; /* all those operations are relocatable */
1364 luaK_fixline(fs, line);
1365}
1366
1367
1368/*
1369** Emit code for binary expressions that "produce values"
1370** (everything but logical operators 'and'/'or' and comparison
1371** operators).
1372** Expression to produce final result will be encoded in 'e1'.
1373*/
1374static void finishbinexpval (FuncState *fs, expdesc *e1, expdesc *e2,
1375 OpCode op, int v2, int flip, int line,
1376 OpCode mmop, TMS event) {
1377 int v1 = luaK_exp2anyreg(fs, e1);
1378 int pc = luaK_codeABCk(fs, op, 0, v1, v2, 0);
1379 freeexps(fs, e1, e2);
1380 e1->u.info = pc;
1381 e1->k = VRELOC; /* all those operations are relocatable */
1382 luaK_fixline(fs, line);
1383 luaK_codeABCk(fs, mmop, v1, v2, event, flip); /* to call metamethod */
1384 luaK_fixline(fs, line);
1385}
1386
1387
1388/*
1389** Emit code for binary expressions that "produce values" over
1390** two registers.
1391*/
1392static void codebinexpval (FuncState *fs, OpCode op,
1393 expdesc *e1, expdesc *e2, int line) {
1394 int v2 = luaK_exp2anyreg(fs, e2); /* both operands are in registers */
1395 lua_assert(OP_ADD <= op && op <= OP_SHR);
1396 finishbinexpval(fs, e1, e2, op, v2, 0, line, OP_MMBIN,
1397 cast(TMS, (op - OP_ADD) + TM_ADD));
1398}
1399
1400
1401/*
1402** Code binary operators with immediate operands.
1403*/
1404static void codebini (FuncState *fs, OpCode op,
1405 expdesc *e1, expdesc *e2, int flip, int line,
1406 TMS event) {
1407 int v2 = int2sC(cast_int(e2->u.ival)); /* immediate operand */
1408 lua_assert(e2->k == VKINT);
1409 finishbinexpval(fs, e1, e2, op, v2, flip, line, OP_MMBINI, event);
1410}
1411
1412
1413/* Try to code a binary operator negating its second operand.
1414** For the metamethod, 2nd operand must keep its original value.
1415*/
1416static int finishbinexpneg (FuncState *fs, expdesc *e1, expdesc *e2,
1417 OpCode op, int line, TMS event) {
1418 if (!luaK_isKint(e2))
1419 return 0; /* not an integer constant */
1420 else {
1421 lua_Integer i2 = e2->u.ival;
1422 if (!(fitsC(i2) && fitsC(-i2)))
1423 return 0; /* not in the proper range */
1424 else { /* operating a small integer constant */
1425 int v2 = cast_int(i2);
1426 finishbinexpval(fs, e1, e2, op, int2sC(-v2), 0, line, OP_MMBINI, event);
1427 /* correct metamethod argument */
1428 SETARG_B(fs->f->code[fs->pc - 1], int2sC(v2));
1429 return 1; /* successfully coded */
1430 }
1431 }
1432}
1433
1434
1435static void swapexps (expdesc *e1, expdesc *e2) {
1436 expdesc temp = *e1; *e1 = *e2; *e2 = temp; /* swap 'e1' and 'e2' */
1437}
1438
1439
1440/*
1441** Code arithmetic operators ('+', '-', ...). If second operand is a
1442** constant in the proper range, use variant opcodes with K operands.
1443*/
1444static void codearith (FuncState *fs, BinOpr opr,
1445 expdesc *e1, expdesc *e2, int flip, int line) {
1446 TMS event = cast(TMS, opr + TM_ADD);
1447 if (tonumeral(e2, NULL) && luaK_exp2K(fs, e2)) { /* K operand? */
1448 int v2 = e2->u.info; /* K index */
1449 OpCode op = cast(OpCode, opr + OP_ADDK);
1450 finishbinexpval(fs, e1, e2, op, v2, flip, line, OP_MMBINK, event);
1451 }
1452 else { /* 'e2' is neither an immediate nor a K operand */
1453 OpCode op = cast(OpCode, opr + OP_ADD);
1454 if (flip)
1455 swapexps(e1, e2); /* back to original order */
1456 codebinexpval(fs, op, e1, e2, line); /* use standard operators */
1457 }
1458}
1459
1460
1461/*
1462** Code commutative operators ('+', '*'). If first operand is a
1463** numeric constant, change order of operands to try to use an
1464** immediate or K operator.
1465*/
1466static void codecommutative (FuncState *fs, BinOpr op,
1467 expdesc *e1, expdesc *e2, int line) {
1468 int flip = 0;
1469 if (tonumeral(e1, NULL)) { /* is first operand a numeric constant? */
1470 swapexps(e1, e2); /* change order */
1471 flip = 1;
1472 }
1473 if (op == OPR_ADD && isSCint(e2)) /* immediate operand? */
1474 codebini(fs, cast(OpCode, OP_ADDI), e1, e2, flip, line, TM_ADD);
1475 else
1476 codearith(fs, op, e1, e2, flip, line);
1477}
1478
1479
1480/*
1481** Code bitwise operations; they are all associative, so the function
1482** tries to put an integer constant as the 2nd operand (a K operand).
1483*/
1484static void codebitwise (FuncState *fs, BinOpr opr,
1485 expdesc *e1, expdesc *e2, int line) {
1486 int flip = 0;
1487 int v2;
1488 OpCode op;
1489 if (e1->k == VKINT && luaK_exp2RK(fs, e1)) {
1490 swapexps(e1, e2); /* 'e2' will be the constant operand */
1491 flip = 1;
1492 }
1493 else if (!(e2->k == VKINT && luaK_exp2RK(fs, e2))) { /* no constants? */
1494 op = cast(OpCode, opr + OP_ADD);
1495 codebinexpval(fs, op, e1, e2, line); /* all-register opcodes */
1496 return;
1497 }
1498 v2 = e2->u.info; /* index in K array */
1499 op = cast(OpCode, opr + OP_ADDK);
1500 lua_assert(ttisinteger(&fs->f->k[v2]));
1501 finishbinexpval(fs, e1, e2, op, v2, flip, line, OP_MMBINK,
1502 cast(TMS, opr + TM_ADD));
1503}
1504
1505
1506/*
1507** Emit code for order comparisons. When using an immediate operand,
1508** 'isfloat' tells whether the original value was a float.
1509*/
1510static void codeorder (FuncState *fs, OpCode op, expdesc *e1, expdesc *e2) {
1511 int r1, r2;
1512 int im;
1513 int isfloat = 0;
1514 if (isSCnumber(e2, &im, &isfloat)) {
1515 /* use immediate operand */
1516 r1 = luaK_exp2anyreg(fs, e1);
1517 r2 = im;
1518 op = cast(OpCode, (op - OP_LT) + OP_LTI);
1519 }
1520 else if (isSCnumber(e1, &im, &isfloat)) {
1521 /* transform (A < B) to (B > A) and (A <= B) to (B >= A) */
1522 r1 = luaK_exp2anyreg(fs, e2);
1523 r2 = im;
1524 op = (op == OP_LT) ? OP_GTI : OP_GEI;
1525 }
1526 else { /* regular case, compare two registers */
1527 r1 = luaK_exp2anyreg(fs, e1);
1528 r2 = luaK_exp2anyreg(fs, e2);
1529 }
1530 freeexps(fs, e1, e2);
1531 e1->u.info = condjump(fs, op, r1, r2, isfloat, 1);
1532 e1->k = VJMP;
1533}
1534
1535
1536/*
1537** Emit code for equality comparisons ('==', '~=').
1538** 'e1' was already put as RK by 'luaK_infix'.
1539*/
1540static void codeeq (FuncState *fs, BinOpr opr, expdesc *e1, expdesc *e2) {
1541 int r1, r2;
1542 int im;
1543 int isfloat = 0; /* not needed here, but kept for symmetry */
1544 OpCode op;
1545 if (e1->k != VNONRELOC) {
1546 lua_assert(e1->k == VK || e1->k == VKINT || e1->k == VKFLT);
1547 swapexps(e1, e2);
1548 }
1549 r1 = luaK_exp2anyreg(fs, e1); /* 1st expression must be in register */
1550 if (isSCnumber(e2, &im, &isfloat)) {
1551 op = OP_EQI;
1552 r2 = im; /* immediate operand */
1553 }
1554 else if (luaK_exp2RK(fs, e2)) { /* 1st expression is constant? */
1555 op = OP_EQK;
1556 r2 = e2->u.info; /* constant index */
1557 }
1558 else {
1559 op = OP_EQ; /* will compare two registers */
1560 r2 = luaK_exp2anyreg(fs, e2);
1561 }
1562 freeexps(fs, e1, e2);
1563 e1->u.info = condjump(fs, op, r1, r2, isfloat, (opr == OPR_EQ));
1564 e1->k = VJMP;
1565}
1566
1567
1568/*
1569** Apply prefix operation 'op' to expression 'e'.
1570*/
1571void luaK_prefix (FuncState *fs, UnOpr op, expdesc *e, int line) {
1572 static const expdesc ef = {VKINT, {0}, NO_JUMP, NO_JUMP};
1573 luaK_dischargevars(fs, e);
1574 switch (op) {
1575 case OPR_MINUS: case OPR_BNOT: /* use 'ef' as fake 2nd operand */
1576 if (constfolding(fs, op + LUA_OPUNM, e, &ef))
1577 break;
1578 /* else */ /* FALLTHROUGH */
1579 case OPR_LEN:
1580 codeunexpval(fs, cast(OpCode, op + OP_UNM), e, line);
1581 break;
1582 case OPR_NOT: codenot(fs, e); break;
1583 default: lua_assert(0);
1584 }
1585}
1586
1587
1588/*
1589** Process 1st operand 'v' of binary operation 'op' before reading
1590** 2nd operand.
1591*/
1592void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) {
1593 luaK_dischargevars(fs, v);
1594 switch (op) {
1595 case OPR_AND: {
1596 luaK_goiftrue(fs, v); /* go ahead only if 'v' is true */
1597 break;
1598 }
1599 case OPR_OR: {
1600 luaK_goiffalse(fs, v); /* go ahead only if 'v' is false */
1601 break;
1602 }
1603 case OPR_CONCAT: {
1604 luaK_exp2nextreg(fs, v); /* operand must be on the stack */
1605 break;
1606 }
1607 case OPR_ADD: case OPR_SUB:
1608 case OPR_MUL: case OPR_DIV: case OPR_IDIV:
1609 case OPR_MOD: case OPR_POW:
1610 case OPR_BAND: case OPR_BOR: case OPR_BXOR:
1611 case OPR_SHL: case OPR_SHR: {
1612 if (!tonumeral(v, NULL))
1613 luaK_exp2anyreg(fs, v);
1614 /* else keep numeral, which may be folded with 2nd operand */
1615 break;
1616 }
1617 case OPR_EQ: case OPR_NE: {
1618 if (!tonumeral(v, NULL))
1619 luaK_exp2RK(fs, v);
1620 /* else keep numeral, which may be an immediate operand */
1621 break;
1622 }
1623 case OPR_LT: case OPR_LE:
1624 case OPR_GT: case OPR_GE: {
1625 int dummy, dummy2;
1626 if (!isSCnumber(v, &dummy, &dummy2))
1627 luaK_exp2anyreg(fs, v);
1628 /* else keep numeral, which may be an immediate operand */
1629 break;
1630 }
1631 default: lua_assert(0);
1632 }
1633}
1634
1635/*
1636** Create code for '(e1 .. e2)'.
1637** For '(e1 .. e2.1 .. e2.2)' (which is '(e1 .. (e2.1 .. e2.2))',
1638** because concatenation is right associative), merge both CONCATs.
1639*/
1640static void codeconcat (FuncState *fs, expdesc *e1, expdesc *e2, int line) {
1641 Instruction *ie2 = previousinstruction(fs);
1642 if (GET_OPCODE(*ie2) == OP_CONCAT) { /* is 'e2' a concatenation? */
1643 int n = GETARG_B(*ie2); /* # of elements concatenated in 'e2' */
1644 lua_assert(e1->u.info + 1 == GETARG_A(*ie2));
1645 freeexp(fs, e2);
1646 SETARG_A(*ie2, e1->u.info); /* correct first element ('e1') */
1647 SETARG_B(*ie2, n + 1); /* will concatenate one more element */
1648 }
1649 else { /* 'e2' is not a concatenation */
1650 luaK_codeABC(fs, OP_CONCAT, e1->u.info, 2, 0); /* new concat opcode */
1651 freeexp(fs, e2);
1652 luaK_fixline(fs, line);
1653 }
1654}
1655
1656
1657/*
1658** Finalize code for binary operation, after reading 2nd operand.
1659*/
1660void luaK_posfix (FuncState *fs, BinOpr opr,
1661 expdesc *e1, expdesc *e2, int line) {
1662 luaK_dischargevars(fs, e2);
1663 if (foldbinop(opr) && constfolding(fs, opr + LUA_OPADD, e1, e2))
1664 return; /* done by folding */
1665 switch (opr) {
1666 case OPR_AND: {
1667 lua_assert(e1->t == NO_JUMP); /* list closed by 'luaK_infix' */
1668 luaK_concat(fs, &e2->f, e1->f);
1669 *e1 = *e2;
1670 break;
1671 }
1672 case OPR_OR: {
1673 lua_assert(e1->f == NO_JUMP); /* list closed by 'luaK_infix' */
1674 luaK_concat(fs, &e2->t, e1->t);
1675 *e1 = *e2;
1676 break;
1677 }
1678 case OPR_CONCAT: { /* e1 .. e2 */
1679 luaK_exp2nextreg(fs, e2);
1680 codeconcat(fs, e1, e2, line);
1681 break;
1682 }
1683 case OPR_ADD: case OPR_MUL: {
1684 codecommutative(fs, opr, e1, e2, line);
1685 break;
1686 }
1687 case OPR_SUB: {
1688 if (finishbinexpneg(fs, e1, e2, OP_ADDI, line, TM_SUB))
1689 break; /* coded as (r1 + -I) */
1690 /* ELSE */
1691 } /* FALLTHROUGH */
1692 case OPR_DIV: case OPR_IDIV: case OPR_MOD: case OPR_POW: {
1693 codearith(fs, opr, e1, e2, 0, line);
1694 break;
1695 }
1696 case OPR_BAND: case OPR_BOR: case OPR_BXOR: {
1697 codebitwise(fs, opr, e1, e2, line);
1698 break;
1699 }
1700 case OPR_SHL: {
1701 if (isSCint(e1)) {
1702 swapexps(e1, e2);
1703 codebini(fs, OP_SHLI, e1, e2, 1, line, TM_SHL); /* I << r2 */
1704 }
1705 else if (finishbinexpneg(fs, e1, e2, OP_SHRI, line, TM_SHL)) {
1706 /* coded as (r1 >> -I) */;
1707 }
1708 else /* regular case (two registers) */
1709 codebinexpval(fs, OP_SHL, e1, e2, line);
1710 break;
1711 }
1712 case OPR_SHR: {
1713 if (isSCint(e2))
1714 codebini(fs, OP_SHRI, e1, e2, 0, line, TM_SHR); /* r1 >> I */
1715 else /* regular case (two registers) */
1716 codebinexpval(fs, OP_SHR, e1, e2, line);
1717 break;
1718 }
1719 case OPR_EQ: case OPR_NE: {
1720 codeeq(fs, opr, e1, e2);
1721 break;
1722 }
1723 case OPR_LT: case OPR_LE: {
1724 OpCode op = cast(OpCode, (opr - OPR_EQ) + OP_EQ);
1725 codeorder(fs, op, e1, e2);
1726 break;
1727 }
1728 case OPR_GT: case OPR_GE: {
1729 /* '(a > b)' <=> '(b < a)'; '(a >= b)' <=> '(b <= a)' */
1730 OpCode op = cast(OpCode, (opr - OPR_NE) + OP_EQ);
1731 swapexps(e1, e2);
1732 codeorder(fs, op, e1, e2);
1733 break;
1734 }
1735 default: lua_assert(0);
1736 }
1737}
1738
1739
1740/*
1741** Change line information associated with current position, by removing
1742** previous info and adding it again with new line.
1743*/
1744void luaK_fixline (FuncState *fs, int line) {
1745 removelastlineinfo(fs);
1746 savelineinfo(fs, fs->f, line);
1747}
1748
1749
1750void luaK_settablesize (FuncState *fs, int pc, int ra, int asize, int hsize) {
1751 Instruction *inst = &fs->f->code[pc];
1752 int rb = (hsize != 0) ? luaO_ceillog2(hsize) + 1 : 0; /* hash size */
1753 int extra = asize / (MAXARG_C + 1); /* higher bits of array size */
1754 int rc = asize % (MAXARG_C + 1); /* lower bits of array size */
1755 int k = (extra > 0); /* true iff needs extra argument */
1756 *inst = CREATE_ABCk(OP_NEWTABLE, ra, rb, rc, k);
1757 *(inst + 1) = CREATE_Ax(OP_EXTRAARG, extra);
1758}
1759
1760
1761/*
1762** Emit a SETLIST instruction.
1763** 'base' is register that keeps table;
1764** 'nelems' is #table plus those to be stored now;
1765** 'tostore' is number of values (in registers 'base + 1',...) to add to
1766** table (or LUA_MULTRET to add up to stack top).
1767*/
1768void luaK_setlist (FuncState *fs, int base, int nelems, int tostore) {
1769 lua_assert(tostore != 0 && tostore <= LFIELDS_PER_FLUSH);
1770 if (tostore == LUA_MULTRET)
1771 tostore = 0;
1772 if (nelems <= MAXARG_C)
1773 luaK_codeABC(fs, OP_SETLIST, base, tostore, nelems);
1774 else {
1775 int extra = nelems / (MAXARG_C + 1);
1776 nelems %= (MAXARG_C + 1);
1777 luaK_codeABCk(fs, OP_SETLIST, base, tostore, nelems, 1);
1778 codeextraarg(fs, extra);
1779 }
1780 fs->freereg = base + 1; /* free registers with list values */
1781}
1782
1783
1784/*
1785** return the final target of a jump (skipping jumps to jumps)
1786*/
1787static int finaltarget (Instruction *code, int i) {
1788 int count;
1789 for (count = 0; count < 100; count++) { /* avoid infinite loops */
1790 Instruction pc = code[i];
1791 if (GET_OPCODE(pc) != OP_JMP)
1792 break;
1793 else
1794 i += GETARG_sJ(pc) + 1;
1795 }
1796 return i;
1797}
1798
1799
1800/*
1801** Do a final pass over the code of a function, doing small peephole
1802** optimizations and adjustments.
1803*/
1804void luaK_finish (FuncState *fs) {
1805 int i;
1806 Proto *p = fs->f;
1807 for (i = 0; i < fs->pc; i++) {
1808 Instruction *pc = &p->code[i];
1809 lua_assert(i == 0 || isOT(*(pc - 1)) == isIT(*pc));
1810 switch (GET_OPCODE(*pc)) {
1811 case OP_RETURN0: case OP_RETURN1: {
1812 if (!(fs->needclose || p->is_vararg))
1813 break; /* no extra work */
1814 /* else use OP_RETURN to do the extra work */
1815 SET_OPCODE(*pc, OP_RETURN);
1816 } /* FALLTHROUGH */
1817 case OP_RETURN: case OP_TAILCALL: {
1818 if (fs->needclose)
1819 SETARG_k(*pc, 1); /* signal that it needs to close */
1820 if (p->is_vararg)
1821 SETARG_C(*pc, p->numparams + 1); /* signal that it is vararg */
1822 break;
1823 }
1824 case OP_JMP: {
1825 int target = finaltarget(p->code, i);
1826 fixjump(fs, i, target);
1827 break;
1828 }
1829 default: break;
1830 }
1831 }
1832}
1833