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*/
418static int 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 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 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 int temp = e->u.var.ridx;
780 e->u.info = temp; /* (can't do a direct assignment; values overlap) */
781 e->k = VNONRELOC; /* becomes a non-relocatable value */
782 break;
783 }
784 case VUPVAL: { /* move value to some (pending) register */
785 e->u.info = luaK_codeABC(fs, OP_GETUPVAL, 0, e->u.info, 0);
786 e->k = VRELOC;
787 break;
788 }
789 case VINDEXUP: {
790 e->u.info = luaK_codeABC(fs, OP_GETTABUP, 0, e->u.ind.t, e->u.ind.idx);
791 e->k = VRELOC;
792 break;
793 }
794 case VINDEXI: {
795 freereg(fs, e->u.ind.t);
796 e->u.info = luaK_codeABC(fs, OP_GETI, 0, e->u.ind.t, e->u.ind.idx);
797 e->k = VRELOC;
798 break;
799 }
800 case VINDEXSTR: {
801 freereg(fs, e->u.ind.t);
802 e->u.info = luaK_codeABC(fs, OP_GETFIELD, 0, e->u.ind.t, e->u.ind.idx);
803 e->k = VRELOC;
804 break;
805 }
806 case VINDEXED: {
807 freeregs(fs, e->u.ind.t, e->u.ind.idx);
808 e->u.info = luaK_codeABC(fs, OP_GETTABLE, 0, e->u.ind.t, e->u.ind.idx);
809 e->k = VRELOC;
810 break;
811 }
812 case VVARARG: case VCALL: {
813 luaK_setoneret(fs, e);
814 break;
815 }
816 default: break; /* there is one value available (somewhere) */
817 }
818}
819
820
821/*
822** Ensure expression value is in register 'reg', making 'e' a
823** non-relocatable expression.
824** (Expression still may have jump lists.)
825*/
826static void discharge2reg (FuncState *fs, expdesc *e, int reg) {
827 luaK_dischargevars(fs, e);
828 switch (e->k) {
829 case VNIL: {
830 luaK_nil(fs, reg, 1);
831 break;
832 }
833 case VFALSE: {
834 luaK_codeABC(fs, OP_LOADFALSE, reg, 0, 0);
835 break;
836 }
837 case VTRUE: {
838 luaK_codeABC(fs, OP_LOADTRUE, reg, 0, 0);
839 break;
840 }
841 case VKSTR: {
842 str2K(fs, e);
843 } /* FALLTHROUGH */
844 case VK: {
845 luaK_codek(fs, reg, e->u.info);
846 break;
847 }
848 case VKFLT: {
849 luaK_float(fs, reg, e->u.nval);
850 break;
851 }
852 case VKINT: {
853 luaK_int(fs, reg, e->u.ival);
854 break;
855 }
856 case VRELOC: {
857 Instruction *pc = &getinstruction(fs, e);
858 SETARG_A(*pc, reg); /* instruction will put result in 'reg' */
859 break;
860 }
861 case VNONRELOC: {
862 if (reg != e->u.info)
863 luaK_codeABC(fs, OP_MOVE, reg, e->u.info, 0);
864 break;
865 }
866 default: {
867 lua_assert(e->k == VJMP);
868 return; /* nothing to do... */
869 }
870 }
871 e->u.info = reg;
872 e->k = VNONRELOC;
873}
874
875
876/*
877** Ensure expression value is in a register, making 'e' a
878** non-relocatable expression.
879** (Expression still may have jump lists.)
880*/
881static void discharge2anyreg (FuncState *fs, expdesc *e) {
882 if (e->k != VNONRELOC) { /* no fixed register yet? */
883 luaK_reserveregs(fs, 1); /* get a register */
884 discharge2reg(fs, e, fs->freereg-1); /* put value there */
885 }
886}
887
888
889static int code_loadbool (FuncState *fs, int A, OpCode op) {
890 luaK_getlabel(fs); /* those instructions may be jump targets */
891 return luaK_codeABC(fs, op, A, 0, 0);
892}
893
894
895/*
896** check whether list has any jump that do not produce a value
897** or produce an inverted value
898*/
899static int need_value (FuncState *fs, int list) {
900 for (; list != NO_JUMP; list = getjump(fs, list)) {
901 Instruction i = *getjumpcontrol(fs, list);
902 if (GET_OPCODE(i) != OP_TESTSET) return 1;
903 }
904 return 0; /* not found */
905}
906
907
908/*
909** Ensures final expression result (which includes results from its
910** jump lists) is in register 'reg'.
911** If expression has jumps, need to patch these jumps either to
912** its final position or to "load" instructions (for those tests
913** that do not produce values).
914*/
915static void exp2reg (FuncState *fs, expdesc *e, int reg) {
916 discharge2reg(fs, e, reg);
917 if (e->k == VJMP) /* expression itself is a test? */
918 luaK_concat(fs, &e->t, e->u.info); /* put this jump in 't' list */
919 if (hasjumps(e)) {
920 int final; /* position after whole expression */
921 int p_f = NO_JUMP; /* position of an eventual LOAD false */
922 int p_t = NO_JUMP; /* position of an eventual LOAD true */
923 if (need_value(fs, e->t) || need_value(fs, e->f)) {
924 int fj = (e->k == VJMP) ? NO_JUMP : luaK_jump(fs);
925 p_f = code_loadbool(fs, reg, OP_LFALSESKIP); /* skip next inst. */
926 p_t = code_loadbool(fs, reg, OP_LOADTRUE);
927 /* jump around these booleans if 'e' is not a test */
928 luaK_patchtohere(fs, fj);
929 }
930 final = luaK_getlabel(fs);
931 patchlistaux(fs, e->f, final, reg, p_f);
932 patchlistaux(fs, e->t, final, reg, p_t);
933 }
934 e->f = e->t = NO_JUMP;
935 e->u.info = reg;
936 e->k = VNONRELOC;
937}
938
939
940/*
941** Ensures final expression result is in next available register.
942*/
943void luaK_exp2nextreg (FuncState *fs, expdesc *e) {
944 luaK_dischargevars(fs, e);
945 freeexp(fs, e);
946 luaK_reserveregs(fs, 1);
947 exp2reg(fs, e, fs->freereg - 1);
948}
949
950
951/*
952** Ensures final expression result is in some (any) register
953** and return that register.
954*/
955int luaK_exp2anyreg (FuncState *fs, expdesc *e) {
956 luaK_dischargevars(fs, e);
957 if (e->k == VNONRELOC) { /* expression already has a register? */
958 if (!hasjumps(e)) /* no jumps? */
959 return e->u.info; /* result is already in a register */
960 if (e->u.info >= luaY_nvarstack(fs)) { /* reg. is not a local? */
961 exp2reg(fs, e, e->u.info); /* put final result in it */
962 return e->u.info;
963 }
964 /* else expression has jumps and cannot change its register
965 to hold the jump values, because it is a local variable.
966 Go through to the default case. */
967 }
968 luaK_exp2nextreg(fs, e); /* default: use next available register */
969 return e->u.info;
970}
971
972
973/*
974** Ensures final expression result is either in a register
975** or in an upvalue.
976*/
977void luaK_exp2anyregup (FuncState *fs, expdesc *e) {
978 if (e->k != VUPVAL || hasjumps(e))
979 luaK_exp2anyreg(fs, e);
980}
981
982
983/*
984** Ensures final expression result is either in a register
985** or it is a constant.
986*/
987void luaK_exp2val (FuncState *fs, expdesc *e) {
988 if (hasjumps(e))
989 luaK_exp2anyreg(fs, e);
990 else
991 luaK_dischargevars(fs, e);
992}
993
994
995/*
996** Try to make 'e' a K expression with an index in the range of R/K
997** indices. Return true iff succeeded.
998*/
999static int luaK_exp2K (FuncState *fs, expdesc *e) {
1000 if (!hasjumps(e)) {
1001 int info;
1002 switch (e->k) { /* move constants to 'k' */
1003 case VTRUE: info = boolT(fs); break;
1004 case VFALSE: info = boolF(fs); break;
1005 case VNIL: info = nilK(fs); break;
1006 case VKINT: info = luaK_intK(fs, e->u.ival); break;
1007 case VKFLT: info = luaK_numberK(fs, e->u.nval); break;
1008 case VKSTR: info = stringK(fs, e->u.strval); break;
1009 case VK: info = e->u.info; break;
1010 default: return 0; /* not a constant */
1011 }
1012 if (info <= MAXINDEXRK) { /* does constant fit in 'argC'? */
1013 e->k = VK; /* make expression a 'K' expression */
1014 e->u.info = info;
1015 return 1;
1016 }
1017 }
1018 /* else, expression doesn't fit; leave it unchanged */
1019 return 0;
1020}
1021
1022
1023/*
1024** Ensures final expression result is in a valid R/K index
1025** (that is, it is either in a register or in 'k' with an index
1026** in the range of R/K indices).
1027** Returns 1 iff expression is K.
1028*/
1029static int exp2RK (FuncState *fs, expdesc *e) {
1030 if (luaK_exp2K(fs, e))
1031 return 1;
1032 else { /* not a constant in the right range: put it in a register */
1033 luaK_exp2anyreg(fs, e);
1034 return 0;
1035 }
1036}
1037
1038
1039static void codeABRK (FuncState *fs, OpCode o, int a, int b,
1040 expdesc *ec) {
1041 int k = exp2RK(fs, ec);
1042 luaK_codeABCk(fs, o, a, b, ec->u.info, k);
1043}
1044
1045
1046/*
1047** Generate code to store result of expression 'ex' into variable 'var'.
1048*/
1049void luaK_storevar (FuncState *fs, expdesc *var, expdesc *ex) {
1050 switch (var->k) {
1051 case VLOCAL: {
1052 freeexp(fs, ex);
1053 exp2reg(fs, ex, var->u.var.ridx); /* compute 'ex' into proper place */
1054 return;
1055 }
1056 case VUPVAL: {
1057 int e = luaK_exp2anyreg(fs, ex);
1058 luaK_codeABC(fs, OP_SETUPVAL, e, var->u.info, 0);
1059 break;
1060 }
1061 case VINDEXUP: {
1062 codeABRK(fs, OP_SETTABUP, var->u.ind.t, var->u.ind.idx, ex);
1063 break;
1064 }
1065 case VINDEXI: {
1066 codeABRK(fs, OP_SETI, var->u.ind.t, var->u.ind.idx, ex);
1067 break;
1068 }
1069 case VINDEXSTR: {
1070 codeABRK(fs, OP_SETFIELD, var->u.ind.t, var->u.ind.idx, ex);
1071 break;
1072 }
1073 case VINDEXED: {
1074 codeABRK(fs, OP_SETTABLE, var->u.ind.t, var->u.ind.idx, ex);
1075 break;
1076 }
1077 default: lua_assert(0); /* invalid var kind to store */
1078 }
1079 freeexp(fs, ex);
1080}
1081
1082
1083/*
1084** Emit SELF instruction (convert expression 'e' into 'e:key(e,').
1085*/
1086void luaK_self (FuncState *fs, expdesc *e, expdesc *key) {
1087 int ereg;
1088 luaK_exp2anyreg(fs, e);
1089 ereg = e->u.info; /* register where 'e' was placed */
1090 freeexp(fs, e);
1091 e->u.info = fs->freereg; /* base register for op_self */
1092 e->k = VNONRELOC; /* self expression has a fixed register */
1093 luaK_reserveregs(fs, 2); /* function and 'self' produced by op_self */
1094 codeABRK(fs, OP_SELF, e->u.info, ereg, key);
1095 freeexp(fs, key);
1096}
1097
1098
1099/*
1100** Negate condition 'e' (where 'e' is a comparison).
1101*/
1102static void negatecondition (FuncState *fs, expdesc *e) {
1103 Instruction *pc = getjumpcontrol(fs, e->u.info);
1104 lua_assert(testTMode(GET_OPCODE(*pc)) && GET_OPCODE(*pc) != OP_TESTSET &&
1105 GET_OPCODE(*pc) != OP_TEST);
1106 SETARG_k(*pc, (GETARG_k(*pc) ^ 1));
1107}
1108
1109
1110/*
1111** Emit instruction to jump if 'e' is 'cond' (that is, if 'cond'
1112** is true, code will jump if 'e' is true.) Return jump position.
1113** Optimize when 'e' is 'not' something, inverting the condition
1114** and removing the 'not'.
1115*/
1116static int jumponcond (FuncState *fs, expdesc *e, int cond) {
1117 if (e->k == VRELOC) {
1118 Instruction ie = getinstruction(fs, e);
1119 if (GET_OPCODE(ie) == OP_NOT) {
1120 removelastinstruction(fs); /* remove previous OP_NOT */
1121 return condjump(fs, OP_TEST, GETARG_B(ie), 0, 0, !cond);
1122 }
1123 /* else go through */
1124 }
1125 discharge2anyreg(fs, e);
1126 freeexp(fs, e);
1127 return condjump(fs, OP_TESTSET, NO_REG, e->u.info, 0, cond);
1128}
1129
1130
1131/*
1132** Emit code to go through if 'e' is true, jump otherwise.
1133*/
1134void luaK_goiftrue (FuncState *fs, expdesc *e) {
1135 int pc; /* pc of new jump */
1136 luaK_dischargevars(fs, e);
1137 switch (e->k) {
1138 case VJMP: { /* condition? */
1139 negatecondition(fs, e); /* jump when it is false */
1140 pc = e->u.info; /* save jump position */
1141 break;
1142 }
1143 case VK: case VKFLT: case VKINT: case VKSTR: case VTRUE: {
1144 pc = NO_JUMP; /* always true; do nothing */
1145 break;
1146 }
1147 default: {
1148 pc = jumponcond(fs, e, 0); /* jump when false */
1149 break;
1150 }
1151 }
1152 luaK_concat(fs, &e->f, pc); /* insert new jump in false list */
1153 luaK_patchtohere(fs, e->t); /* true list jumps to here (to go through) */
1154 e->t = NO_JUMP;
1155}
1156
1157
1158/*
1159** Emit code to go through if 'e' is false, jump otherwise.
1160*/
1161void luaK_goiffalse (FuncState *fs, expdesc *e) {
1162 int pc; /* pc of new jump */
1163 luaK_dischargevars(fs, e);
1164 switch (e->k) {
1165 case VJMP: {
1166 pc = e->u.info; /* already jump if true */
1167 break;
1168 }
1169 case VNIL: case VFALSE: {
1170 pc = NO_JUMP; /* always false; do nothing */
1171 break;
1172 }
1173 default: {
1174 pc = jumponcond(fs, e, 1); /* jump if true */
1175 break;
1176 }
1177 }
1178 luaK_concat(fs, &e->t, pc); /* insert new jump in 't' list */
1179 luaK_patchtohere(fs, e->f); /* false list jumps to here (to go through) */
1180 e->f = NO_JUMP;
1181}
1182
1183
1184/*
1185** Code 'not e', doing constant folding.
1186*/
1187static void codenot (FuncState *fs, expdesc *e) {
1188 switch (e->k) {
1189 case VNIL: case VFALSE: {
1190 e->k = VTRUE; /* true == not nil == not false */
1191 break;
1192 }
1193 case VK: case VKFLT: case VKINT: case VKSTR: case VTRUE: {
1194 e->k = VFALSE; /* false == not "x" == not 0.5 == not 1 == not true */
1195 break;
1196 }
1197 case VJMP: {
1198 negatecondition(fs, e);
1199 break;
1200 }
1201 case VRELOC:
1202 case VNONRELOC: {
1203 discharge2anyreg(fs, e);
1204 freeexp(fs, e);
1205 e->u.info = luaK_codeABC(fs, OP_NOT, 0, e->u.info, 0);
1206 e->k = VRELOC;
1207 break;
1208 }
1209 default: lua_assert(0); /* cannot happen */
1210 }
1211 /* interchange true and false lists */
1212 { int temp = e->f; e->f = e->t; e->t = temp; }
1213 removevalues(fs, e->f); /* values are useless when negated */
1214 removevalues(fs, e->t);
1215}
1216
1217
1218/*
1219** Check whether expression 'e' is a short literal string
1220*/
1221static int isKstr (FuncState *fs, expdesc *e) {
1222 return (e->k == VK && !hasjumps(e) && e->u.info <= MAXARG_B &&
1223 ttisshrstring(&fs->f->k[e->u.info]));
1224}
1225
1226/*
1227** Check whether expression 'e' is a literal integer.
1228*/
1229static int isKint (expdesc *e) {
1230 return (e->k == VKINT && !hasjumps(e));
1231}
1232
1233
1234/*
1235** Check whether expression 'e' is a literal integer in
1236** proper range to fit in register C
1237*/
1238static int isCint (expdesc *e) {
1239 return isKint(e) && (l_castS2U(e->u.ival) <= l_castS2U(MAXARG_C));
1240}
1241
1242
1243/*
1244** Check whether expression 'e' is a literal integer in
1245** proper range to fit in register sC
1246*/
1247static int isSCint (expdesc *e) {
1248 return isKint(e) && fitsC(e->u.ival);
1249}
1250
1251
1252/*
1253** Check whether expression 'e' is a literal integer or float in
1254** proper range to fit in a register (sB or sC).
1255*/
1256static int isSCnumber (expdesc *e, int *pi, int *isfloat) {
1257 lua_Integer i;
1258 if (e->k == VKINT)
1259 i = e->u.ival;
1260 else if (e->k == VKFLT && luaV_flttointeger(e->u.nval, &i, F2Ieq))
1261 *isfloat = 1;
1262 else
1263 return 0; /* not a number */
1264 if (!hasjumps(e) && fitsC(i)) {
1265 *pi = int2sC(cast_int(i));
1266 return 1;
1267 }
1268 else
1269 return 0;
1270}
1271
1272
1273/*
1274** Create expression 't[k]'. 't' must have its final result already in a
1275** register or upvalue. Upvalues can only be indexed by literal strings.
1276** Keys can be literal strings in the constant table or arbitrary
1277** values in registers.
1278*/
1279void luaK_indexed (FuncState *fs, expdesc *t, expdesc *k) {
1280 if (k->k == VKSTR)
1281 str2K(fs, k);
1282 lua_assert(!hasjumps(t) &&
1283 (t->k == VLOCAL || t->k == VNONRELOC || t->k == VUPVAL));
1284 if (t->k == VUPVAL && !isKstr(fs, k)) /* upvalue indexed by non 'Kstr'? */
1285 luaK_exp2anyreg(fs, t); /* put it in a register */
1286 if (t->k == VUPVAL) {
1287 int temp = t->u.info; /* upvalue index */
1288 lua_assert(isKstr(fs, k));
1289 t->u.ind.t = temp; /* (can't do a direct assignment; values overlap) */
1290 t->u.ind.idx = k->u.info; /* literal short string */
1291 t->k = VINDEXUP;
1292 }
1293 else {
1294 /* register index of the table */
1295 t->u.ind.t = (t->k == VLOCAL) ? t->u.var.ridx: t->u.info;
1296 if (isKstr(fs, k)) {
1297 t->u.ind.idx = k->u.info; /* literal short string */
1298 t->k = VINDEXSTR;
1299 }
1300 else if (isCint(k)) {
1301 t->u.ind.idx = cast_int(k->u.ival); /* int. constant in proper range */
1302 t->k = VINDEXI;
1303 }
1304 else {
1305 t->u.ind.idx = luaK_exp2anyreg(fs, k); /* register */
1306 t->k = VINDEXED;
1307 }
1308 }
1309}
1310
1311
1312/*
1313** Return false if folding can raise an error.
1314** Bitwise operations need operands convertible to integers; division
1315** operations cannot have 0 as divisor.
1316*/
1317static int validop (int op, TValue *v1, TValue *v2) {
1318 switch (op) {
1319 case LUA_OPBAND: case LUA_OPBOR: case LUA_OPBXOR:
1320 case LUA_OPSHL: case LUA_OPSHR: case LUA_OPBNOT: { /* conversion errors */
1321 lua_Integer i;
1322 return (luaV_tointegerns(v1, &i, LUA_FLOORN2I) &&
1323 luaV_tointegerns(v2, &i, LUA_FLOORN2I));
1324 }
1325 case LUA_OPDIV: case LUA_OPIDIV: case LUA_OPMOD: /* division by 0 */
1326 return (nvalue(v2) != 0);
1327 default: return 1; /* everything else is valid */
1328 }
1329}
1330
1331
1332/*
1333** Try to "constant-fold" an operation; return 1 iff successful.
1334** (In this case, 'e1' has the final result.)
1335*/
1336static int constfolding (FuncState *fs, int op, expdesc *e1,
1337 const expdesc *e2) {
1338 TValue v1, v2, res;
1339 if (!tonumeral(e1, &v1) || !tonumeral(e2, &v2) || !validop(op, &v1, &v2))
1340 return 0; /* non-numeric operands or not safe to fold */
1341 luaO_rawarith(fs->ls->L, op, &v1, &v2, &res); /* does operation */
1342 if (ttisinteger(&res)) {
1343 e1->k = VKINT;
1344 e1->u.ival = ivalue(&res);
1345 }
1346 else { /* folds neither NaN nor 0.0 (to avoid problems with -0.0) */
1347 lua_Number n = fltvalue(&res);
1348 if (luai_numisnan(n) || n == 0)
1349 return 0;
1350 e1->k = VKFLT;
1351 e1->u.nval = n;
1352 }
1353 return 1;
1354}
1355
1356
1357/*
1358** Convert a BinOpr to an OpCode (ORDER OPR - ORDER OP)
1359*/
1360l_sinline OpCode binopr2op (BinOpr opr, BinOpr baser, OpCode base) {
1361 lua_assert(baser <= opr &&
1362 ((baser == OPR_ADD && opr <= OPR_SHR) ||
1363 (baser == OPR_LT && opr <= OPR_LE)));
1364 return cast(OpCode, (cast_int(opr) - cast_int(baser)) + cast_int(base));
1365}
1366
1367
1368/*
1369** Convert a UnOpr to an OpCode (ORDER OPR - ORDER OP)
1370*/
1371l_sinline OpCode unopr2op (UnOpr opr) {
1372 return cast(OpCode, (cast_int(opr) - cast_int(OPR_MINUS)) +
1373 cast_int(OP_UNM));
1374}
1375
1376
1377/*
1378** Convert a BinOpr to a tag method (ORDER OPR - ORDER TM)
1379*/
1380l_sinline TMS binopr2TM (BinOpr opr) {
1381 lua_assert(OPR_ADD <= opr && opr <= OPR_SHR);
1382 return cast(TMS, (cast_int(opr) - cast_int(OPR_ADD)) + cast_int(TM_ADD));
1383}
1384
1385
1386/*
1387** Emit code for unary expressions that "produce values"
1388** (everything but 'not').
1389** Expression to produce final result will be encoded in 'e'.
1390*/
1391static void codeunexpval (FuncState *fs, OpCode op, expdesc *e, int line) {
1392 int r = luaK_exp2anyreg(fs, e); /* opcodes operate only on registers */
1393 freeexp(fs, e);
1394 e->u.info = luaK_codeABC(fs, op, 0, r, 0); /* generate opcode */
1395 e->k = VRELOC; /* all those operations are relocatable */
1396 luaK_fixline(fs, line);
1397}
1398
1399
1400/*
1401** Emit code for binary expressions that "produce values"
1402** (everything but logical operators 'and'/'or' and comparison
1403** operators).
1404** Expression to produce final result will be encoded in 'e1'.
1405*/
1406static void finishbinexpval (FuncState *fs, expdesc *e1, expdesc *e2,
1407 OpCode op, int v2, int flip, int line,
1408 OpCode mmop, TMS event) {
1409 int v1 = luaK_exp2anyreg(fs, e1);
1410 int pc = luaK_codeABCk(fs, op, 0, v1, v2, 0);
1411 freeexps(fs, e1, e2);
1412 e1->u.info = pc;
1413 e1->k = VRELOC; /* all those operations are relocatable */
1414 luaK_fixline(fs, line);
1415 luaK_codeABCk(fs, mmop, v1, v2, event, flip); /* to call metamethod */
1416 luaK_fixline(fs, line);
1417}
1418
1419
1420/*
1421** Emit code for binary expressions that "produce values" over
1422** two registers.
1423*/
1424static void codebinexpval (FuncState *fs, BinOpr opr,
1425 expdesc *e1, expdesc *e2, int line) {
1426 OpCode op = binopr2op(opr, OPR_ADD, OP_ADD);
1427 int v2 = luaK_exp2anyreg(fs, e2); /* make sure 'e2' is in a register */
1428 /* 'e1' must be already in a register or it is a constant */
1429 lua_assert((VNIL <= e1->k && e1->k <= VKSTR) ||
1430 e1->k == VNONRELOC || e1->k == VRELOC);
1431 lua_assert(OP_ADD <= op && op <= OP_SHR);
1432 finishbinexpval(fs, e1, e2, op, v2, 0, line, OP_MMBIN, binopr2TM(opr));
1433}
1434
1435
1436/*
1437** Code binary operators with immediate operands.
1438*/
1439static void codebini (FuncState *fs, OpCode op,
1440 expdesc *e1, expdesc *e2, int flip, int line,
1441 TMS event) {
1442 int v2 = int2sC(cast_int(e2->u.ival)); /* immediate operand */
1443 lua_assert(e2->k == VKINT);
1444 finishbinexpval(fs, e1, e2, op, v2, flip, line, OP_MMBINI, event);
1445}
1446
1447
1448/*
1449** Code binary operators with K operand.
1450*/
1451static void codebinK (FuncState *fs, BinOpr opr,
1452 expdesc *e1, expdesc *e2, int flip, int line) {
1453 TMS event = binopr2TM(opr);
1454 int v2 = e2->u.info; /* K index */
1455 OpCode op = binopr2op(opr, OPR_ADD, OP_ADDK);
1456 finishbinexpval(fs, e1, e2, op, v2, flip, line, OP_MMBINK, event);
1457}
1458
1459
1460/* Try to code a binary operator negating its second operand.
1461** For the metamethod, 2nd operand must keep its original value.
1462*/
1463static int finishbinexpneg (FuncState *fs, expdesc *e1, expdesc *e2,
1464 OpCode op, int line, TMS event) {
1465 if (!isKint(e2))
1466 return 0; /* not an integer constant */
1467 else {
1468 lua_Integer i2 = e2->u.ival;
1469 if (!(fitsC(i2) && fitsC(-i2)))
1470 return 0; /* not in the proper range */
1471 else { /* operating a small integer constant */
1472 int v2 = cast_int(i2);
1473 finishbinexpval(fs, e1, e2, op, int2sC(-v2), 0, line, OP_MMBINI, event);
1474 /* correct metamethod argument */
1475 SETARG_B(fs->f->code[fs->pc - 1], int2sC(v2));
1476 return 1; /* successfully coded */
1477 }
1478 }
1479}
1480
1481
1482static void swapexps (expdesc *e1, expdesc *e2) {
1483 expdesc temp = *e1; *e1 = *e2; *e2 = temp; /* swap 'e1' and 'e2' */
1484}
1485
1486
1487/*
1488** Code binary operators with no constant operand.
1489*/
1490static void codebinNoK (FuncState *fs, BinOpr opr,
1491 expdesc *e1, expdesc *e2, int flip, int line) {
1492 if (flip)
1493 swapexps(e1, e2); /* back to original order */
1494 codebinexpval(fs, opr, e1, e2, line); /* use standard operators */
1495}
1496
1497
1498/*
1499** Code arithmetic operators ('+', '-', ...). If second operand is a
1500** constant in the proper range, use variant opcodes with K operands.
1501*/
1502static void codearith (FuncState *fs, BinOpr opr,
1503 expdesc *e1, expdesc *e2, int flip, int line) {
1504 if (tonumeral(e2, NULL) && luaK_exp2K(fs, e2)) /* K operand? */
1505 codebinK(fs, opr, e1, e2, flip, line);
1506 else /* 'e2' is neither an immediate nor a K operand */
1507 codebinNoK(fs, opr, e1, e2, flip, line);
1508}
1509
1510
1511/*
1512** Code commutative operators ('+', '*'). If first operand is a
1513** numeric constant, change order of operands to try to use an
1514** immediate or K operator.
1515*/
1516static void codecommutative (FuncState *fs, BinOpr op,
1517 expdesc *e1, expdesc *e2, int line) {
1518 int flip = 0;
1519 if (tonumeral(e1, NULL)) { /* is first operand a numeric constant? */
1520 swapexps(e1, e2); /* change order */
1521 flip = 1;
1522 }
1523 if (op == OPR_ADD && isSCint(e2)) /* immediate operand? */
1524 codebini(fs, OP_ADDI, e1, e2, flip, line, TM_ADD);
1525 else
1526 codearith(fs, op, e1, e2, flip, line);
1527}
1528
1529
1530/*
1531** Code bitwise operations; they are all commutative, so the function
1532** tries to put an integer constant as the 2nd operand (a K operand).
1533*/
1534static void codebitwise (FuncState *fs, BinOpr opr,
1535 expdesc *e1, expdesc *e2, int line) {
1536 int flip = 0;
1537 if (e1->k == VKINT) {
1538 swapexps(e1, e2); /* 'e2' will be the constant operand */
1539 flip = 1;
1540 }
1541 if (e2->k == VKINT && luaK_exp2K(fs, e2)) /* K operand? */
1542 codebinK(fs, opr, e1, e2, flip, line);
1543 else /* no constants */
1544 codebinNoK(fs, opr, e1, e2, flip, line);
1545}
1546
1547
1548/*
1549** Emit code for order comparisons. When using an immediate operand,
1550** 'isfloat' tells whether the original value was a float.
1551*/
1552static void codeorder (FuncState *fs, BinOpr opr, expdesc *e1, expdesc *e2) {
1553 int r1, r2;
1554 int im;
1555 int isfloat = 0;
1556 OpCode op;
1557 if (isSCnumber(e2, &im, &isfloat)) {
1558 /* use immediate operand */
1559 r1 = luaK_exp2anyreg(fs, e1);
1560 r2 = im;
1561 op = binopr2op(opr, OPR_LT, OP_LTI);
1562 }
1563 else if (isSCnumber(e1, &im, &isfloat)) {
1564 /* transform (A < B) to (B > A) and (A <= B) to (B >= A) */
1565 r1 = luaK_exp2anyreg(fs, e2);
1566 r2 = im;
1567 op = binopr2op(opr, OPR_LT, OP_GTI);
1568 }
1569 else { /* regular case, compare two registers */
1570 r1 = luaK_exp2anyreg(fs, e1);
1571 r2 = luaK_exp2anyreg(fs, e2);
1572 op = binopr2op(opr, OPR_LT, OP_LT);
1573 }
1574 freeexps(fs, e1, e2);
1575 e1->u.info = condjump(fs, op, r1, r2, isfloat, 1);
1576 e1->k = VJMP;
1577}
1578
1579
1580/*
1581** Emit code for equality comparisons ('==', '~=').
1582** 'e1' was already put as RK by 'luaK_infix'.
1583*/
1584static void codeeq (FuncState *fs, BinOpr opr, expdesc *e1, expdesc *e2) {
1585 int r1, r2;
1586 int im;
1587 int isfloat = 0; /* not needed here, but kept for symmetry */
1588 OpCode op;
1589 if (e1->k != VNONRELOC) {
1590 lua_assert(e1->k == VK || e1->k == VKINT || e1->k == VKFLT);
1591 swapexps(e1, e2);
1592 }
1593 r1 = luaK_exp2anyreg(fs, e1); /* 1st expression must be in register */
1594 if (isSCnumber(e2, &im, &isfloat)) {
1595 op = OP_EQI;
1596 r2 = im; /* immediate operand */
1597 }
1598 else if (exp2RK(fs, e2)) { /* 2nd expression is constant? */
1599 op = OP_EQK;
1600 r2 = e2->u.info; /* constant index */
1601 }
1602 else {
1603 op = OP_EQ; /* will compare two registers */
1604 r2 = luaK_exp2anyreg(fs, e2);
1605 }
1606 freeexps(fs, e1, e2);
1607 e1->u.info = condjump(fs, op, r1, r2, isfloat, (opr == OPR_EQ));
1608 e1->k = VJMP;
1609}
1610
1611
1612/*
1613** Apply prefix operation 'op' to expression 'e'.
1614*/
1615void luaK_prefix (FuncState *fs, UnOpr opr, expdesc *e, int line) {
1616 static const expdesc ef = {VKINT, {0}, NO_JUMP, NO_JUMP};
1617 luaK_dischargevars(fs, e);
1618 switch (opr) {
1619 case OPR_MINUS: case OPR_BNOT: /* use 'ef' as fake 2nd operand */
1620 if (constfolding(fs, opr + LUA_OPUNM, e, &ef))
1621 break;
1622 /* else */ /* FALLTHROUGH */
1623 case OPR_LEN:
1624 codeunexpval(fs, unopr2op(opr), e, line);
1625 break;
1626 case OPR_NOT: codenot(fs, e); break;
1627 default: lua_assert(0);
1628 }
1629}
1630
1631
1632/*
1633** Process 1st operand 'v' of binary operation 'op' before reading
1634** 2nd operand.
1635*/
1636void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) {
1637 luaK_dischargevars(fs, v);
1638 switch (op) {
1639 case OPR_AND: {
1640 luaK_goiftrue(fs, v); /* go ahead only if 'v' is true */
1641 break;
1642 }
1643 case OPR_OR: {
1644 luaK_goiffalse(fs, v); /* go ahead only if 'v' is false */
1645 break;
1646 }
1647 case OPR_CONCAT: {
1648 luaK_exp2nextreg(fs, v); /* operand must be on the stack */
1649 break;
1650 }
1651 case OPR_ADD: case OPR_SUB:
1652 case OPR_MUL: case OPR_DIV: case OPR_IDIV:
1653 case OPR_MOD: case OPR_POW:
1654 case OPR_BAND: case OPR_BOR: case OPR_BXOR:
1655 case OPR_SHL: case OPR_SHR: {
1656 if (!tonumeral(v, NULL))
1657 luaK_exp2anyreg(fs, v);
1658 /* else keep numeral, which may be folded or used as an immediate
1659 operand */
1660 break;
1661 }
1662 case OPR_EQ: case OPR_NE: {
1663 if (!tonumeral(v, NULL))
1664 exp2RK(fs, v);
1665 /* else keep numeral, which may be an immediate operand */
1666 break;
1667 }
1668 case OPR_LT: case OPR_LE:
1669 case OPR_GT: case OPR_GE: {
1670 int dummy, dummy2;
1671 if (!isSCnumber(v, &dummy, &dummy2))
1672 luaK_exp2anyreg(fs, v);
1673 /* else keep numeral, which may be an immediate operand */
1674 break;
1675 }
1676 default: lua_assert(0);
1677 }
1678}
1679
1680/*
1681** Create code for '(e1 .. e2)'.
1682** For '(e1 .. e2.1 .. e2.2)' (which is '(e1 .. (e2.1 .. e2.2))',
1683** because concatenation is right associative), merge both CONCATs.
1684*/
1685static void codeconcat (FuncState *fs, expdesc *e1, expdesc *e2, int line) {
1686 Instruction *ie2 = previousinstruction(fs);
1687 if (GET_OPCODE(*ie2) == OP_CONCAT) { /* is 'e2' a concatenation? */
1688 int n = GETARG_B(*ie2); /* # of elements concatenated in 'e2' */
1689 lua_assert(e1->u.info + 1 == GETARG_A(*ie2));
1690 freeexp(fs, e2);
1691 SETARG_A(*ie2, e1->u.info); /* correct first element ('e1') */
1692 SETARG_B(*ie2, n + 1); /* will concatenate one more element */
1693 }
1694 else { /* 'e2' is not a concatenation */
1695 luaK_codeABC(fs, OP_CONCAT, e1->u.info, 2, 0); /* new concat opcode */
1696 freeexp(fs, e2);
1697 luaK_fixline(fs, line);
1698 }
1699}
1700
1701
1702/*
1703** Finalize code for binary operation, after reading 2nd operand.
1704*/
1705void luaK_posfix (FuncState *fs, BinOpr opr,
1706 expdesc *e1, expdesc *e2, int line) {
1707 luaK_dischargevars(fs, e2);
1708 if (foldbinop(opr) && constfolding(fs, opr + LUA_OPADD, e1, e2))
1709 return; /* done by folding */
1710 switch (opr) {
1711 case OPR_AND: {
1712 lua_assert(e1->t == NO_JUMP); /* list closed by 'luaK_infix' */
1713 luaK_concat(fs, &e2->f, e1->f);
1714 *e1 = *e2;
1715 break;
1716 }
1717 case OPR_OR: {
1718 lua_assert(e1->f == NO_JUMP); /* list closed by 'luaK_infix' */
1719 luaK_concat(fs, &e2->t, e1->t);
1720 *e1 = *e2;
1721 break;
1722 }
1723 case OPR_CONCAT: { /* e1 .. e2 */
1724 luaK_exp2nextreg(fs, e2);
1725 codeconcat(fs, e1, e2, line);
1726 break;
1727 }
1728 case OPR_ADD: case OPR_MUL: {
1729 codecommutative(fs, opr, e1, e2, line);
1730 break;
1731 }
1732 case OPR_SUB: {
1733 if (finishbinexpneg(fs, e1, e2, OP_ADDI, line, TM_SUB))
1734 break; /* coded as (r1 + -I) */
1735 /* ELSE */
1736 } /* FALLTHROUGH */
1737 case OPR_DIV: case OPR_IDIV: case OPR_MOD: case OPR_POW: {
1738 codearith(fs, opr, e1, e2, 0, line);
1739 break;
1740 }
1741 case OPR_BAND: case OPR_BOR: case OPR_BXOR: {
1742 codebitwise(fs, opr, e1, e2, line);
1743 break;
1744 }
1745 case OPR_SHL: {
1746 if (isSCint(e1)) {
1747 swapexps(e1, e2);
1748 codebini(fs, OP_SHLI, e1, e2, 1, line, TM_SHL); /* I << r2 */
1749 }
1750 else if (finishbinexpneg(fs, e1, e2, OP_SHRI, line, TM_SHL)) {
1751 /* coded as (r1 >> -I) */;
1752 }
1753 else /* regular case (two registers) */
1754 codebinexpval(fs, opr, e1, e2, line);
1755 break;
1756 }
1757 case OPR_SHR: {
1758 if (isSCint(e2))
1759 codebini(fs, OP_SHRI, e1, e2, 0, line, TM_SHR); /* r1 >> I */
1760 else /* regular case (two registers) */
1761 codebinexpval(fs, opr, e1, e2, line);
1762 break;
1763 }
1764 case OPR_EQ: case OPR_NE: {
1765 codeeq(fs, opr, e1, e2);
1766 break;
1767 }
1768 case OPR_GT: case OPR_GE: {
1769 /* '(a > b)' <=> '(b < a)'; '(a >= b)' <=> '(b <= a)' */
1770 swapexps(e1, e2);
1771 opr = cast(BinOpr, (opr - OPR_GT) + OPR_LT);
1772 } /* FALLTHROUGH */
1773 case OPR_LT: case OPR_LE: {
1774 codeorder(fs, opr, e1, e2);
1775 break;
1776 }
1777 default: lua_assert(0);
1778 }
1779}
1780
1781
1782/*
1783** Change line information associated with current position, by removing
1784** previous info and adding it again with new line.
1785*/
1786void luaK_fixline (FuncState *fs, int line) {
1787 removelastlineinfo(fs);
1788 savelineinfo(fs, fs->f, line);
1789}
1790
1791
1792void luaK_settablesize (FuncState *fs, int pc, int ra, int asize, int hsize) {
1793 Instruction *inst = &fs->f->code[pc];
1794 int rb = (hsize != 0) ? luaO_ceillog2(hsize) + 1 : 0; /* hash size */
1795 int extra = asize / (MAXARG_C + 1); /* higher bits of array size */
1796 int rc = asize % (MAXARG_C + 1); /* lower bits of array size */
1797 int k = (extra > 0); /* true iff needs extra argument */
1798 *inst = CREATE_ABCk(OP_NEWTABLE, ra, rb, rc, k);
1799 *(inst + 1) = CREATE_Ax(OP_EXTRAARG, extra);
1800}
1801
1802
1803/*
1804** Emit a SETLIST instruction.
1805** 'base' is register that keeps table;
1806** 'nelems' is #table plus those to be stored now;
1807** 'tostore' is number of values (in registers 'base + 1',...) to add to
1808** table (or LUA_MULTRET to add up to stack top).
1809*/
1810void luaK_setlist (FuncState *fs, int base, int nelems, int tostore) {
1811 lua_assert(tostore != 0 && tostore <= LFIELDS_PER_FLUSH);
1812 if (tostore == LUA_MULTRET)
1813 tostore = 0;
1814 if (nelems <= MAXARG_C)
1815 luaK_codeABC(fs, OP_SETLIST, base, tostore, nelems);
1816 else {
1817 int extra = nelems / (MAXARG_C + 1);
1818 nelems %= (MAXARG_C + 1);
1819 luaK_codeABCk(fs, OP_SETLIST, base, tostore, nelems, 1);
1820 codeextraarg(fs, extra);
1821 }
1822 fs->freereg = base + 1; /* free registers with list values */
1823}
1824
1825
1826/*
1827** return the final target of a jump (skipping jumps to jumps)
1828*/
1829static int finaltarget (Instruction *code, int i) {
1830 int count;
1831 for (count = 0; count < 100; count++) { /* avoid infinite loops */
1832 Instruction pc = code[i];
1833 if (GET_OPCODE(pc) != OP_JMP)
1834 break;
1835 else
1836 i += GETARG_sJ(pc) + 1;
1837 }
1838 return i;
1839}
1840
1841
1842/*
1843** Do a final pass over the code of a function, doing small peephole
1844** optimizations and adjustments.
1845*/
1846void luaK_finish (FuncState *fs) {
1847 int i;
1848 Proto *p = fs->f;
1849 for (i = 0; i < fs->pc; i++) {
1850 Instruction *pc = &p->code[i];
1851 lua_assert(i == 0 || isOT(*(pc - 1)) == isIT(*pc));
1852 switch (GET_OPCODE(*pc)) {
1853 case OP_RETURN0: case OP_RETURN1: {
1854 if (!(fs->needclose || p->is_vararg))
1855 break; /* no extra work */
1856 /* else use OP_RETURN to do the extra work */
1857 SET_OPCODE(*pc, OP_RETURN);
1858 } /* FALLTHROUGH */
1859 case OP_RETURN: case OP_TAILCALL: {
1860 if (fs->needclose)
1861 SETARG_k(*pc, 1); /* signal that it needs to close */
1862 if (p->is_vararg)
1863 SETARG_C(*pc, p->numparams + 1); /* signal that it is vararg */
1864 break;
1865 }
1866 case OP_JMP: {
1867 int target = finaltarget(p->code, i);
1868 fixjump(fs, i, target);
1869 break;
1870 }
1871 default: break;
1872 }
1873 }
1874}