/*** $Id: lcode.c,v 2.99 2014/12/29 16:49:25 roberto Exp $** Code generator for Lua** See Copyright Notice in lua.h*/ #define lcode_c#define LUA_CORE #include "lprefix.h"  #include <math.h>#include <stdlib.h> #include "lua.h" #include "lcode.h"#include "ldebug.h"#include "ldo.h"#include "lgc.h"#include "llex.h"#include "lmem.h"#include "lobject.h"#include "lopcodes.h"#include "lparser.h"#include "lstring.h"#include "ltable.h"#include "lvm.h"  /* Maximum number of registers in a Lua function */#define MAXREGS		250  #define hasjumps(e)	((e)->t != (e)->f)  static int tonumeral(expdesc *e, TValue *v) {  if (e->t != NO_JUMP || e->f != NO_JUMP)    return 0;  /* not a numeral */  switch (e->k) {    case VKINT:      if (v) setivalue(v, e->u.ival);      return 1;    case VKFLT:      if (v) setfltvalue(v, e->u.nval);      return 1;    default: return 0;  }}  void luaK_nil (FuncState *fs, int from, int n) {  Instruction *previous;  int l = from + n - 1;  /* last register to set nil */  if (fs->pc > fs->lasttarget) {  /* no jumps to current position? */    previous = &fs->f->code[fs->pc-1];    if (GET_OPCODE(*previous) == OP_LOADNIL) {      int pfrom = GETARG_A(*previous);      int pl = pfrom + GETARG_B(*previous);      if ((pfrom <= from && from <= pl + 1) ||          (from <= pfrom && pfrom <= l + 1)) {  /* can connect both? */        if (pfrom < from) from = pfrom;  /* from = min(from, pfrom) */        if (pl > l) l = pl;  /* l = max(l, pl) */        SETARG_A(*previous, from);        SETARG_B(*previous, l - from);        return;      }    }  /* else go through */  }  luaK_codeABC(fs, OP_LOADNIL, from, n - 1, 0);  /* else no optimization */}  int luaK_jump (FuncState *fs) {  int jpc = fs->jpc;  /* save list of jumps to here */  int j;  fs->jpc = NO_JUMP;  j = luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP);  luaK_concat(fs, &j, jpc);  /* keep them on hold */  return j;}  void luaK_ret (FuncState *fs, int first, int nret) {  luaK_codeABC(fs, OP_RETURN, first, nret+1, 0);}  static int condjump (FuncState *fs, OpCode op, int A, int B, int C) {  luaK_codeABC(fs, op, A, B, C);  return luaK_jump(fs);}  static void fixjump (FuncState *fs, int pc, int dest) {  Instruction *jmp = &fs->f->code[pc];  int offset = dest-(pc+1);  lua_assert(dest != NO_JUMP);  if (abs(offset) > MAXARG_sBx)    luaX_syntaxerror(fs->ls, "control structure too long");  SETARG_sBx(*jmp, offset);}  /*** returns current 'pc' and marks it as a jump target (to avoid wrong** optimizations with consecutive instructions not in the same basic block).*/int luaK_getlabel (FuncState *fs) {  fs->lasttarget = fs->pc;  return fs->pc;}  static int getjump (FuncState *fs, int pc) {  int offset = GETARG_sBx(fs->f->code[pc]);  if (offset == NO_JUMP)  /* point to itself represents end of list */    return NO_JUMP;  /* end of list */  else    return (pc+1)+offset;  /* turn offset into absolute position */}  static Instruction *getjumpcontrol (FuncState *fs, int pc) {  Instruction *pi = &fs->f->code[pc];  if (pc >= 1 && testTMode(GET_OPCODE(*(pi-1))))    return pi-1;  else    return pi;}  /*** check whether list has any jump that do not produce a value** (or produce an inverted value)*/static int need_value (FuncState *fs, int list) {  for (; list != NO_JUMP; list = getjump(fs, list)) {    Instruction i = *getjumpcontrol(fs, list);    if (GET_OPCODE(i) != OP_TESTSET) return 1;  }  return 0;  /* not found */}  static int patchtestreg (FuncState *fs, int node, int reg) {  Instruction *i = getjumpcontrol(fs, node);  if (GET_OPCODE(*i) != OP_TESTSET)    return 0;  /* cannot patch other instructions */  if (reg != NO_REG && reg != GETARG_B(*i))    SETARG_A(*i, reg);  else  /* no register to put value or register already has the value */    *i = CREATE_ABC(OP_TEST, GETARG_B(*i), 0, GETARG_C(*i));   return 1;}  static void removevalues (FuncState *fs, int list) {  for (; list != NO_JUMP; list = getjump(fs, list))      patchtestreg(fs, list, NO_REG);}  static void patchlistaux (FuncState *fs, int list, int vtarget, int reg,                          int dtarget) {  while (list != NO_JUMP) {    int next = getjump(fs, list);    if (patchtestreg(fs, list, reg))      fixjump(fs, list, vtarget);    else      fixjump(fs, list, dtarget);  /* jump to default target */    list = next;  }}  static void dischargejpc (FuncState *fs) {  patchlistaux(fs, fs->jpc, fs->pc, NO_REG, fs->pc);  fs->jpc = NO_JUMP;}  void luaK_patchlist (FuncState *fs, int list, int target) {  if (target == fs->pc)    luaK_patchtohere(fs, list);  else {    lua_assert(target < fs->pc);    patchlistaux(fs, list, target, NO_REG, target);  }}  void luaK_patchclose (FuncState *fs, int list, int level) {  level++;  /* argument is +1 to reserve 0 as non-op */  while (list != NO_JUMP) {    int next = getjump(fs, list);    lua_assert(GET_OPCODE(fs->f->code[list]) == OP_JMP &&                (GETARG_A(fs->f->code[list]) == 0 ||                 GETARG_A(fs->f->code[list]) >= level));    SETARG_A(fs->f->code[list], level);    list = next;  }}  void luaK_patchtohere (FuncState *fs, int list) {  luaK_getlabel(fs);  luaK_concat(fs, &fs->jpc, list);}  void luaK_concat (FuncState *fs, int *l1, int l2) {  if (l2 == NO_JUMP) return;  else if (*l1 == NO_JUMP)    *l1 = l2;  else {    int list = *l1;    int next;    while ((next = getjump(fs, list)) != NO_JUMP)  /* find last element */      list = next;    fixjump(fs, list, l2);  }}  static int luaK_code (FuncState *fs, Instruction i) {  Proto *f = fs->f;  dischargejpc(fs);  /* 'pc' will change */  /* put new instruction in code array */  luaM_growvector(fs->ls->L, f->code, fs->pc, f->sizecode, Instruction,                  MAX_INT, "opcodes");  f->code[fs->pc] = i;  /* save corresponding line information */  luaM_growvector(fs->ls->L, f->lineinfo, fs->pc, f->sizelineinfo, int,                  MAX_INT, "opcodes");  f->lineinfo[fs->pc] = fs->ls->lastline;  return fs->pc++;}  int luaK_codeABC (FuncState *fs, OpCode o, int a, int b, int c) {  lua_assert(getOpMode(o) == iABC);  lua_assert(getBMode(o) != OpArgN || b == 0);  lua_assert(getCMode(o) != OpArgN || c == 0);  lua_assert(a <= MAXARG_A && b <= MAXARG_B && c <= MAXARG_C);  return luaK_code(fs, CREATE_ABC(o, a, b, c));}  int luaK_codeABx (FuncState *fs, OpCode o, int a, unsigned int bc) {  lua_assert(getOpMode(o) == iABx || getOpMode(o) == iAsBx);  lua_assert(getCMode(o) == OpArgN);  lua_assert(a <= MAXARG_A && bc <= MAXARG_Bx);  return luaK_code(fs, CREATE_ABx(o, a, bc));}  static int codeextraarg (FuncState *fs, int a) {  lua_assert(a <= MAXARG_Ax);  return luaK_code(fs, CREATE_Ax(OP_EXTRAARG, a));}  int luaK_codek (FuncState *fs, int reg, int k) {  if (k <= MAXARG_Bx)    return luaK_codeABx(fs, OP_LOADK, reg, k);  else {    int p = luaK_codeABx(fs, OP_LOADKX, reg, 0);    codeextraarg(fs, k);    return p;  }}  void luaK_checkstack (FuncState *fs, int n) {  int newstack = fs->freereg + n;  if (newstack > fs->f->maxstacksize) {    if (newstack >= MAXREGS)      luaX_syntaxerror(fs->ls, "function or expression too complex");    fs->f->maxstacksize = cast_byte(newstack);  }}  void luaK_reserveregs (FuncState *fs, int n) {  luaK_checkstack(fs, n);  fs->freereg += n;}  static void freereg (FuncState *fs, int reg) {  if (!ISK(reg) && reg >= fs->nactvar) {    fs->freereg--;    lua_assert(reg == fs->freereg);  }}  static void freeexp (FuncState *fs, expdesc *e) {  if (e->k == VNONRELOC)    freereg(fs, e->u.info);}  /*** Use scanner's table to cache position of constants in constant list** and try to reuse constants*/static int addk (FuncState *fs, TValue *key, TValue *v) {  lua_State *L = fs->ls->L;  Proto *f = fs->f;  TValue *idx = luaH_set(L, fs->ls->h, key);  /* index scanner table */  int k, oldsize;  if (ttisinteger(idx)) {  /* is there an index there? */    k = cast_int(ivalue(idx));    /* correct value? (warning: must distinguish floats from integers!) */    if (k < fs->nk && ttype(&f->k[k]) == ttype(v) &&                      luaV_rawequalobj(&f->k[k], v))      return k;  /* reuse index */  }  /* constant not found; create a new entry */  oldsize = f->sizek;  k = fs->nk;  /* numerical value does not need GC barrier;     table has no metatable, so it does not need to invalidate cache */  setivalue(idx, k);  luaM_growvector(L, f->k, k, f->sizek, TValue, MAXARG_Ax, "constants");  while (oldsize < f->sizek) setnilvalue(&f->k[oldsize++]);  setobj(L, &f->k[k], v);  fs->nk++;  luaC_barrier(L, f, v);  return k;}  int luaK_stringK (FuncState *fs, TString *s) {  TValue o;  setsvalue(fs->ls->L, &o, s);  return addk(fs, &o, &o);}  /*** Integers use userdata as keys to avoid collision with floats with same** value; conversion to 'void*' used only for hashing, no "precision"** problems*/int luaK_intK (FuncState *fs, lua_Integer n) {  TValue k, o;  setpvalue(&k, cast(void*, cast(size_t, n)));  setivalue(&o, n);  return addk(fs, &k, &o);}  static int luaK_numberK (FuncState *fs, lua_Number r) {  TValue o;  setfltvalue(&o, r);  return addk(fs, &o, &o);}  static int boolK (FuncState *fs, int b) {  TValue o;  setbvalue(&o, b);  return addk(fs, &o, &o);}  static int nilK (FuncState *fs) {  TValue k, v;  setnilvalue(&v);  /* cannot use nil as key; instead use table itself to represent nil */  sethvalue(fs->ls->L, &k, fs->ls->h);  return addk(fs, &k, &v);}  void luaK_setreturns (FuncState *fs, expdesc *e, int nresults) {  if (e->k == VCALL) {  /* expression is an open function call? */    SETARG_C(getcode(fs, e), nresults+1);  }  else if (e->k == VVARARG) {    SETARG_B(getcode(fs, e), nresults+1);    SETARG_A(getcode(fs, e), fs->freereg);    luaK_reserveregs(fs, 1);  }}  void luaK_setoneret (FuncState *fs, expdesc *e) {  if (e->k == VCALL) {  /* expression is an open function call? */    e->k = VNONRELOC;    e->u.info = GETARG_A(getcode(fs, e));  }  else if (e->k == VVARARG) {    SETARG_B(getcode(fs, e), 2);    e->k = VRELOCABLE;  /* can relocate its simple result */  }}  void luaK_dischargevars (FuncState *fs, expdesc *e) {  switch (e->k) {    case VLOCAL: {      e->k = VNONRELOC;      break;    }    case VUPVAL: {      e->u.info = luaK_codeABC(fs, OP_GETUPVAL, 0, e->u.info, 0);      e->k = VRELOCABLE;      break;    }    case VINDEXED: {      OpCode op = OP_GETTABUP;  /* assume 't' is in an upvalue */      freereg(fs, e->u.ind.idx);      if (e->u.ind.vt == VLOCAL) {  /* 't' is in a register? */        freereg(fs, e->u.ind.t);        op = OP_GETTABLE;      }      e->u.info = luaK_codeABC(fs, op, 0, e->u.ind.t, e->u.ind.idx);      e->k = VRELOCABLE;      break;    }    case VVARARG:    case VCALL: {      luaK_setoneret(fs, e);      break;    }    default: break;  /* there is one value available (somewhere) */  }}  static int code_label (FuncState *fs, int A, int b, int jump) {  luaK_getlabel(fs);  /* those instructions may be jump targets */  return luaK_codeABC(fs, OP_LOADBOOL, A, b, jump);}  static void discharge2reg (FuncState *fs, expdesc *e, int reg) {  luaK_dischargevars(fs, e);  switch (e->k) {    case VNIL: {      luaK_nil(fs, reg, 1);      break;    }    case VFALSE: case VTRUE: {      luaK_codeABC(fs, OP_LOADBOOL, reg, e->k == VTRUE, 0);      break;    }    case VK: {      luaK_codek(fs, reg, e->u.info);      break;    }    case VKFLT: {      luaK_codek(fs, reg, luaK_numberK(fs, e->u.nval));      break;    }    case VKINT: {      luaK_codek(fs, reg, luaK_intK(fs, e->u.ival));      break;    }    case VRELOCABLE: {      Instruction *pc = &getcode(fs, e);      SETARG_A(*pc, reg);      break;    }    case VNONRELOC: {      if (reg != e->u.info)        luaK_codeABC(fs, OP_MOVE, reg, e->u.info, 0);      break;    }    default: {      lua_assert(e->k == VVOID || e->k == VJMP);      return;  /* nothing to do... */    }  }  e->u.info = reg;  e->k = VNONRELOC;}  static void discharge2anyreg (FuncState *fs, expdesc *e) {  if (e->k != VNONRELOC) {    luaK_reserveregs(fs, 1);    discharge2reg(fs, e, fs->freereg-1);  }}  static void exp2reg (FuncState *fs, expdesc *e, int reg) {  discharge2reg(fs, e, reg);  if (e->k == VJMP)    luaK_concat(fs, &e->t, e->u.info);  /* put this jump in 't' list */  if (hasjumps(e)) {    int final;  /* position after whole expression */

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