diff options
Diffstat (limited to 'libs/liblua/src/lcode.c')
| -rw-r--r-- | libs/liblua/src/lcode.c | 701 |
1 files changed, 473 insertions, 228 deletions
diff --git a/libs/liblua/src/lcode.c b/libs/liblua/src/lcode.c index 5e34624bf4..2cd0dd2d5c 100644 --- a/libs/liblua/src/lcode.c +++ b/libs/liblua/src/lcode.c @@ -1,5 +1,5 @@ /* -** $Id: lcode.c,v 2.99 2014/12/29 16:49:25 roberto Exp $ +** $Id: lcode.c,v 2.109 2016/05/13 19:09:21 roberto Exp $ ** Code generator for Lua ** See Copyright Notice in lua.h */ @@ -29,15 +29,19 @@ #include "lvm.h" -/* Maximum number of registers in a Lua function */ -#define MAXREGS 250 +/* Maximum number of registers in a Lua function (must fit in 8 bits) */ +#define MAXREGS 255 #define hasjumps(e) ((e)->t != (e)->f) +/* +** If expression is a numeric constant, fills 'v' with its value +** and returns 1. Otherwise, returns 0. +*/ static int tonumeral(expdesc *e, TValue *v) { - if (e->t != NO_JUMP || e->f != NO_JUMP) + if (hasjumps(e)) return 0; /* not a numeral */ switch (e->k) { case VKINT: @@ -51,13 +55,19 @@ static int tonumeral(expdesc *e, TValue *v) { } +/* +** Create a OP_LOADNIL instruction, but try to optimize: if the previous +** instruction is also OP_LOADNIL and ranges are compatible, adjust +** range of previous instruction instead of emitting a new one. (For +** instance, 'local a; local b' will generate a single opcode.) +*/ 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); + if (GET_OPCODE(*previous) == OP_LOADNIL) { /* previous is LOADNIL? */ + int pfrom = GETARG_A(*previous); /* get previous range */ int pl = pfrom + GETARG_B(*previous); if ((pfrom <= from && from <= pl + 1) || (from <= pfrom && pfrom <= l + 1)) { /* can connect both? */ @@ -73,37 +83,84 @@ void luaK_nil (FuncState *fs, int from, int n) { } +/* +** Gets the destination address of a jump instruction. Used to traverse +** a list of jumps. +*/ +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 */ +} + + +/* +** Fix jump instruction at position 'pc' to jump to 'dest'. +** (Jump addresses are relative in Lua) +*/ +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); +} + + +/* +** Concatenate jump-list 'l2' into jump-list 'l1' +*/ +void luaK_concat (FuncState *fs, int *l1, int l2) { + if (l2 == NO_JUMP) return; /* nothing to concatenate? */ + else if (*l1 == NO_JUMP) /* no original list? */ + *l1 = l2; /* 'l1' points to 'l2' */ + else { + int list = *l1; + int next; + while ((next = getjump(fs, list)) != NO_JUMP) /* find last element */ + list = next; + fixjump(fs, list, l2); /* last element links to 'l2' */ + } +} + + +/* +** Create a jump instruction and return its position, so its destination +** can be fixed later (with 'fixjump'). If there are jumps to +** this position (kept in 'jpc'), link them all together so that +** 'patchlistaux' will fix all them directly to the final destination. +*/ int luaK_jump (FuncState *fs) { int jpc = fs->jpc; /* save list of jumps to here */ int j; - fs->jpc = NO_JUMP; + fs->jpc = NO_JUMP; /* no more jumps to here */ j = luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP); luaK_concat(fs, &j, jpc); /* keep them on hold */ return j; } +/* +** Code a 'return' instruction +*/ void luaK_ret (FuncState *fs, int first, int nret) { luaK_codeABC(fs, OP_RETURN, first, nret+1, 0); } +/* +** Code a "conditional jump", that is, a test or comparison opcode +** followed by a jump. Return jump position. +*/ 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). @@ -114,15 +171,11 @@ int luaK_getlabel (FuncState *fs) { } -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 */ -} - - +/* +** Returns the position of the instruction "controlling" a given +** jump (that is, its condition), or the jump itself if it is +** unconditional. +*/ static Instruction *getjumpcontrol (FuncState *fs, int pc) { Instruction *pi = &fs->f->code[pc]; if (pc >= 1 && testTMode(GET_OPCODE(*(pi-1)))) @@ -133,37 +186,41 @@ static Instruction *getjumpcontrol (FuncState *fs, int pc) { /* -** check whether list has any jump that do not produce a value -** (or produce an inverted value) +** Patch destination register for a TESTSET instruction. +** If instruction in position 'node' is not a TESTSET, return 0 ("fails"). +** Otherwise, if 'reg' is not 'NO_REG', set it as the destination +** register. Otherwise, change instruction to a simple 'TEST' (produces +** no register 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 */ + else { + /* no register to put value or register already has the value; + change instruction to simple test */ *i = CREATE_ABC(OP_TEST, GETARG_B(*i), 0, GETARG_C(*i)); - + } return 1; } +/* +** Traverse a list of tests ensuring no one produces a value +*/ static void removevalues (FuncState *fs, int list) { for (; list != NO_JUMP; list = getjump(fs, list)) patchtestreg(fs, list, NO_REG); } +/* +** Traverse a list of tests, patching their destination address and +** registers: tests producing values jump to 'vtarget' (and put their +** values in 'reg'), other tests jump to 'dtarget'. +*/ static void patchlistaux (FuncState *fs, int list, int vtarget, int reg, int dtarget) { while (list != NO_JUMP) { @@ -177,15 +234,35 @@ static void patchlistaux (FuncState *fs, int list, int vtarget, int reg, } +/* +** Ensure all pending jumps to current position are fixed (jumping +** to current position with no values) and reset list of pending +** jumps +*/ static void dischargejpc (FuncState *fs) { patchlistaux(fs, fs->jpc, fs->pc, NO_REG, fs->pc); fs->jpc = NO_JUMP; } +/* +** Add elements in 'list' to list of pending jumps to "here" +** (current position) +*/ +void luaK_patchtohere (FuncState *fs, int list) { + luaK_getlabel(fs); /* mark "here" as a jump target */ + luaK_concat(fs, &fs->jpc, list); +} + + +/* +** Path all jumps in 'list' to jump to 'target'. +** (The assert means that we cannot fix a jump to a forward address +** because we only know addresses once code is generated.) +*/ void luaK_patchlist (FuncState *fs, int list, int target) { - if (target == fs->pc) - luaK_patchtohere(fs, list); + if (target == fs->pc) /* 'target' is current position? */ + luaK_patchtohere(fs, list); /* add list to pending jumps */ else { lua_assert(target < fs->pc); patchlistaux(fs, list, target, NO_REG, target); @@ -193,39 +270,26 @@ void luaK_patchlist (FuncState *fs, int list, int target) { } +/* +** Path all jumps in 'list' to close upvalues up to given 'level' +** (The assertion checks that jumps either were closing nothing +** or were closing higher levels, from inner blocks.) +*/ 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); + for (; list != NO_JUMP; list = 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); } } +/* +** Emit instruction 'i', checking for array sizes and saving also its +** line information. Return 'i' position. +*/ static int luaK_code (FuncState *fs, Instruction i) { Proto *f = fs->f; dischargejpc(fs); /* 'pc' will change */ @@ -241,6 +305,10 @@ static int luaK_code (FuncState *fs, Instruction i) { } +/* +** Format and emit an 'iABC' instruction. (Assertions check consistency +** of parameters versus opcode.) +*/ 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); @@ -250,6 +318,9 @@ int luaK_codeABC (FuncState *fs, OpCode o, int a, int b, int c) { } +/* +** Format and emit an 'iABx' instruction. +*/ 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); @@ -258,12 +329,20 @@ int luaK_codeABx (FuncState *fs, OpCode o, int a, unsigned int bc) { } +/* +** Emit an "extra argument" instruction (format 'iAx') +*/ static int codeextraarg (FuncState *fs, int a) { lua_assert(a <= MAXARG_Ax); return luaK_code(fs, CREATE_Ax(OP_EXTRAARG, a)); } +/* +** Emit a "load constant" instruction, using either 'OP_LOADK' +** (if constant index 'k' fits in 18 bits) or an 'OP_LOADKX' +** instruction with "extra argument". +*/ int luaK_codek (FuncState *fs, int reg, int k) { if (k <= MAXARG_Bx) return luaK_codeABx(fs, OP_LOADK, reg, k); @@ -275,22 +354,35 @@ int luaK_codek (FuncState *fs, int reg, int k) { } +/* +** Check register-stack level, keeping track of its maximum size +** in field 'maxstacksize' +*/ 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"); + luaX_syntaxerror(fs->ls, + "function or expression needs too many registers"); fs->f->maxstacksize = cast_byte(newstack); } } +/* +** Reserve 'n' registers in register stack +*/ void luaK_reserveregs (FuncState *fs, int n) { luaK_checkstack(fs, n); fs->freereg += n; } +/* +** Free register 'reg', if it is neither a constant index nor +** a local variable. +) +*/ static void freereg (FuncState *fs, int reg) { if (!ISK(reg) && reg >= fs->nactvar) { fs->freereg--; @@ -299,6 +391,9 @@ static void freereg (FuncState *fs, int reg) { } +/* +** Free register used by expression 'e' (if any) +*/ static void freeexp (FuncState *fs, expdesc *e) { if (e->k == VNONRELOC) freereg(fs, e->u.info); @@ -306,8 +401,29 @@ static void freeexp (FuncState *fs, expdesc *e) { /* +** Free registers used by expressions 'e1' and 'e2' (if any) in proper +** order. +*/ +static void freeexps (FuncState *fs, expdesc *e1, expdesc *e2) { + int r1 = (e1->k == VNONRELOC) ? e1->u.info : -1; + int r2 = (e2->k == VNONRELOC) ? e2->u.info : -1; + if (r1 > r2) { + freereg(fs, r1); + freereg(fs, r2); + } + else { + freereg(fs, r2); + freereg(fs, r1); + } +} + + +/* +** Add constant 'v' to prototype's list of constants (field 'k'). ** Use scanner's table to cache position of constants in constant list -** and try to reuse constants +** and try to reuse constants. Because some values should not be used +** as keys (nil cannot be a key, integer keys can collapse with float +** keys), the caller must provide a useful 'key' for indexing the cache. */ static int addk (FuncState *fs, TValue *key, TValue *v) { lua_State *L = fs->ls->L; @@ -336,17 +452,21 @@ static int addk (FuncState *fs, TValue *key, TValue *v) { } +/* +** Add a string to list of constants and return its index. +*/ int luaK_stringK (FuncState *fs, TString *s) { TValue o; setsvalue(fs->ls->L, &o, s); - return addk(fs, &o, &o); + return addk(fs, &o, &o); /* use string itself as key */ } /* -** Integers use userdata as keys to avoid collision with floats with same -** value; conversion to 'void*' used only for hashing, no "precision" -** problems +** Add an integer to list of constants and return its index. +** Integers use userdata as keys to avoid collision with floats with +** same value; conversion to 'void*' is used only for hashing, so there +** are no "precision" problems. */ int luaK_intK (FuncState *fs, lua_Integer n) { TValue k, o; @@ -355,21 +475,29 @@ int luaK_intK (FuncState *fs, lua_Integer n) { return addk(fs, &k, &o); } - +/* +** Add a float to list of constants and return its index. +*/ static int luaK_numberK (FuncState *fs, lua_Number r) { TValue o; setfltvalue(&o, r); - return addk(fs, &o, &o); + return addk(fs, &o, &o); /* use number itself as key */ } +/* +** Add a boolean to list of constants and return its index. +*/ static int boolK (FuncState *fs, int b) { TValue o; setbvalue(&o, b); - return addk(fs, &o, &o); + return addk(fs, &o, &o); /* use boolean itself as key */ } +/* +** Add nil to list of constants and return its index. +*/ static int nilK (FuncState *fs) { TValue k, v; setnilvalue(&v); @@ -379,54 +507,79 @@ static int nilK (FuncState *fs) { } +/* +** Fix an expression to return the number of results 'nresults'. +** Either 'e' is a multi-ret expression (function call or vararg) +** or 'nresults' is LUA_MULTRET (as any expression can satisfy that). +*/ 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); + SETARG_C(getinstruction(fs, e), nresults + 1); } else if (e->k == VVARARG) { - SETARG_B(getcode(fs, e), nresults+1); - SETARG_A(getcode(fs, e), fs->freereg); + Instruction *pc = &getinstruction(fs, e); + SETARG_B(*pc, nresults + 1); + SETARG_A(*pc, fs->freereg); luaK_reserveregs(fs, 1); } + else lua_assert(nresults == LUA_MULTRET); } +/* +** Fix an expression to return one result. +** If expression is not a multi-ret expression (function call or +** vararg), it already returns one result, so nothing needs to be done. +** Function calls become VNONRELOC expressions (as its result comes +** fixed in the base register of the call), while vararg expressions +** become VRELOCABLE (as OP_VARARG puts its results where it wants). +** (Calls are created returning one result, so that does not need +** to be fixed.) +*/ 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)); + /* already returns 1 value */ + lua_assert(GETARG_C(getinstruction(fs, e)) == 2); + e->k = VNONRELOC; /* result has fixed position */ + e->u.info = GETARG_A(getinstruction(fs, e)); } else if (e->k == VVARARG) { - SETARG_B(getcode(fs, e), 2); + SETARG_B(getinstruction(fs, e), 2); e->k = VRELOCABLE; /* can relocate its simple result */ } } +/* +** Ensure that expression 'e' is not a variable. +*/ void luaK_dischargevars (FuncState *fs, expdesc *e) { switch (e->k) { - case VLOCAL: { - e->k = VNONRELOC; + case VLOCAL: { /* already in a register */ + e->k = VNONRELOC; /* becomes a non-relocatable value */ break; } - case VUPVAL: { + case VUPVAL: { /* move value to some (pending) register */ 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 */ + OpCode op; freereg(fs, e->u.ind.idx); - if (e->u.ind.vt == VLOCAL) { /* 't' is in a register? */ + if (e->u.ind.vt == VLOCAL) { /* is 't' in a register? */ freereg(fs, e->u.ind.t); op = OP_GETTABLE; } + else { + lua_assert(e->u.ind.vt == VUPVAL); + op = OP_GETTABUP; /* 't' is in an upvalue */ + } e->u.info = luaK_codeABC(fs, op, 0, e->u.ind.t, e->u.ind.idx); e->k = VRELOCABLE; break; } - case VVARARG: - case VCALL: { + case VVARARG: case VCALL: { luaK_setoneret(fs, e); break; } @@ -435,12 +588,10 @@ void luaK_dischargevars (FuncState *fs, expdesc *e) { } -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); -} - - +/* +** Ensures expression value is in register 'reg' (and therefore +** 'e' will become a non-relocatable expression). +*/ static void discharge2reg (FuncState *fs, expdesc *e, int reg) { luaK_dischargevars(fs, e); switch (e->k) { @@ -465,8 +616,8 @@ static void discharge2reg (FuncState *fs, expdesc *e, int reg) { break; } case VRELOCABLE: { - Instruction *pc = &getcode(fs, e); - SETARG_A(*pc, reg); + Instruction *pc = &getinstruction(fs, e); + SETARG_A(*pc, reg); /* instruction will put result in 'reg' */ break; } case VNONRELOC: { @@ -475,7 +626,7 @@ static void discharge2reg (FuncState *fs, expdesc *e, int reg) { break; } default: { - lua_assert(e->k == VVOID || e->k == VJMP); + lua_assert(e->k == VJMP); return; /* nothing to do... */ } } @@ -484,17 +635,46 @@ static void discharge2reg (FuncState *fs, expdesc *e, int reg) { } +/* +** Ensures expression value is in any register. +*/ static void discharge2anyreg (FuncState *fs, expdesc *e) { - if (e->k != VNONRELOC) { - luaK_reserveregs(fs, 1); - discharge2reg(fs, e, fs->freereg-1); + if (e->k != VNONRELOC) { /* no fixed register yet? */ + luaK_reserveregs(fs, 1); /* get a register */ + discharge2reg(fs, e, fs->freereg-1); /* put value there */ } } +static int code_loadbool (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); +} + + +/* +** 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 */ +} + + +/* +** Ensures final expression result (including results from its jump +** lists) is in register 'reg'. +** If expression has jumps, need to patch these jumps either to +** its final position or to "load" instructions (for those tests +** that do not produce values). +*/ static void exp2reg (FuncState *fs, expdesc *e, int reg) { discharge2reg(fs, e, reg); - if (e->k == VJMP) + if (e->k == VJMP) /* expression itself is a test? */ luaK_concat(fs, &e->t, e->u.info); /* put this jump in 't' list */ if (hasjumps(e)) { int final; /* position after whole expression */ @@ -502,8 +682,8 @@ static void exp2reg (FuncState *fs, expdesc *e, int reg) { int p_t = NO_JUMP; /* position of an eventual LOAD true */ if (need_value(fs, e->t) || need_value(fs, e->f)) { int fj = (e->k == VJMP) ? NO_JUMP : luaK_jump(fs); - p_f = code_label(fs, reg, 0, 1); - p_t = code_label(fs, reg, 1, 0); + p_f = code_loadbool(fs, reg, 0, 1); + p_t = code_loadbool(fs, reg, 1, 0); luaK_patchtohere(fs, fj); } final = luaK_getlabel(fs); @@ -516,6 +696,10 @@ static void exp2reg (FuncState *fs, expdesc *e, int reg) { } +/* +** Ensures final expression result (including results from its jump +** lists) is in next available register. +*/ void luaK_exp2nextreg (FuncState *fs, expdesc *e) { luaK_dischargevars(fs, e); freeexp(fs, e); @@ -524,26 +708,39 @@ void luaK_exp2nextreg (FuncState *fs, expdesc *e) { } +/* +** Ensures final expression result (including results from its jump +** lists) is in some (any) register and return that register. +*/ int luaK_exp2anyreg (FuncState *fs, expdesc *e) { luaK_dischargevars(fs, e); - if (e->k == VNONRELOC) { - if (!hasjumps(e)) return e->u.info; /* exp is already in a register */ + if (e->k == VNONRELOC) { /* expression already has a register? */ + if (!hasjumps(e)) /* no jumps? */ + return e->u.info; /* result is already in a register */ if (e->u.info >= fs->nactvar) { /* reg. is not a local? */ - exp2reg(fs, e, e->u.info); /* put value on it */ + exp2reg(fs, e, e->u.info); /* put final result in it */ return e->u.info; } } - luaK_exp2nextreg(fs, e); /* default */ + luaK_exp2nextreg(fs, e); /* otherwise, use next available register */ return e->u.info; } +/* +** Ensures final expression result is either in a register or in an +** upvalue. +*/ void luaK_exp2anyregup (FuncState *fs, expdesc *e) { if (e->k != VUPVAL || hasjumps(e)) luaK_exp2anyreg(fs, e); } +/* +** Ensures final expression result is either in a register or it is +** a constant. +*/ void luaK_exp2val (FuncState *fs, expdesc *e) { if (hasjumps(e)) luaK_exp2anyreg(fs, e); @@ -552,35 +749,26 @@ void luaK_exp2val (FuncState *fs, expdesc *e) { } +/* +** Ensures final expression result is in a valid R/K index +** (that is, it is either in a register or in 'k' with an index +** in the range of R/K indices). +** Returns R/K index. +*/ int luaK_exp2RK (FuncState *fs, expdesc *e) { luaK_exp2val(fs, e); - switch (e->k) { - case VTRUE: - case VFALSE: - case VNIL: { - if (fs->nk <= MAXINDEXRK) { /* constant fits in RK operand? */ - e->u.info = (e->k == VNIL) ? nilK(fs) : boolK(fs, (e->k == VTRUE)); - e->k = VK; - return RKASK(e->u.info); - } - else break; - } - case VKINT: { - e->u.info = luaK_intK(fs, e->u.ival); - e->k = VK; - goto vk; - } - case VKFLT: { - e->u.info = luaK_numberK(fs, e->u.nval); - e->k = VK; - /* go through */ - } - case VK: { + switch (e->k) { /* move constants to 'k' */ + case VTRUE: e->u.info = boolK(fs, 1); goto vk; + case VFALSE: e->u.info = boolK(fs, 0); goto vk; + case VNIL: e->u.info = nilK(fs); goto vk; + case VKINT: e->u.info = luaK_intK(fs, e->u.ival); goto vk; + case VKFLT: e->u.info = luaK_numberK(fs, e->u.nval); goto vk; + case VK: vk: + e->k = VK; if (e->u.info <= MAXINDEXRK) /* constant fits in 'argC'? */ return RKASK(e->u.info); else break; - } default: break; } /* not a constant in the right range: put it in a register */ @@ -588,11 +776,14 @@ int luaK_exp2RK (FuncState *fs, expdesc *e) { } +/* +** Generate code to store result of expression 'ex' into variable 'var'. +*/ void luaK_storevar (FuncState *fs, expdesc *var, expdesc *ex) { switch (var->k) { case VLOCAL: { freeexp(fs, ex); - exp2reg(fs, ex, var->u.info); + exp2reg(fs, ex, var->u.info); /* compute 'ex' into proper place */ return; } case VUPVAL: { @@ -606,29 +797,32 @@ void luaK_storevar (FuncState *fs, expdesc *var, expdesc *ex) { luaK_codeABC(fs, op, var->u.ind.t, var->u.ind.idx, e); break; } - default: { - lua_assert(0); /* invalid var kind to store */ - break; - } + default: lua_assert(0); /* invalid var kind to store */ } freeexp(fs, ex); } +/* +** Emit SELF instruction (convert expression 'e' into 'e:key(e,'). +*/ void luaK_self (FuncState *fs, expdesc *e, expdesc *key) { int ereg; luaK_exp2anyreg(fs, e); ereg = e->u.info; /* register where 'e' was placed */ freeexp(fs, e); e->u.info = fs->freereg; /* base register for op_self */ - e->k = VNONRELOC; + e->k = VNONRELOC; /* self expression has a fixed register */ luaK_reserveregs(fs, 2); /* function and 'self' produced by op_self */ luaK_codeABC(fs, OP_SELF, e->u.info, ereg, luaK_exp2RK(fs, key)); freeexp(fs, key); } -static void invertjump (FuncState *fs, expdesc *e) { +/* +** Negate condition 'e' (where 'e' is a comparison). +*/ +static void negatecondition (FuncState *fs, expdesc *e) { Instruction *pc = getjumpcontrol(fs, e->u.info); lua_assert(testTMode(GET_OPCODE(*pc)) && GET_OPCODE(*pc) != OP_TESTSET && GET_OPCODE(*pc) != OP_TEST); @@ -636,9 +830,15 @@ static void invertjump (FuncState *fs, expdesc *e) { } +/* +** Emit instruction to jump if 'e' is 'cond' (that is, if 'cond' +** is true, code will jump if 'e' is true.) Return jump position. +** Optimize when 'e' is 'not' something, inverting the condition +** and removing the 'not'. +*/ static int jumponcond (FuncState *fs, expdesc *e, int cond) { if (e->k == VRELOCABLE) { - Instruction ie = getcode(fs, e); + Instruction ie = getinstruction(fs, e); if (GET_OPCODE(ie) == OP_NOT) { fs->pc--; /* remove previous OP_NOT */ return condjump(fs, OP_TEST, GETARG_B(ie), 0, !cond); @@ -651,13 +851,16 @@ static int jumponcond (FuncState *fs, expdesc *e, int cond) { } +/* +** Emit code to go through if 'e' is true, jump otherwise. +*/ void luaK_goiftrue (FuncState *fs, expdesc *e) { - int pc; /* pc of last jump */ + int pc; /* pc of new jump */ luaK_dischargevars(fs, e); switch (e->k) { - case VJMP: { - invertjump(fs, e); - pc = e->u.info; + case VJMP: { /* condition? */ + negatecondition(fs, e); /* jump when it is false */ + pc = e->u.info; /* save jump position */ break; } case VK: case VKFLT: case VKINT: case VTRUE: { @@ -665,22 +868,25 @@ void luaK_goiftrue (FuncState *fs, expdesc *e) { break; } default: { - pc = jumponcond(fs, e, 0); + pc = jumponcond(fs, e, 0); /* jump when false */ break; } } - luaK_concat(fs, &e->f, pc); /* insert last jump in 'f' list */ - luaK_patchtohere(fs, e->t); + luaK_concat(fs, &e->f, pc); /* insert new jump in false list */ + luaK_patchtohere(fs, e->t); /* true list jumps to here (to go through) */ e->t = NO_JUMP; } +/* +** Emit code to go through if 'e' is false, jump otherwise. +*/ void luaK_goiffalse (FuncState *fs, expdesc *e) { - int pc; /* pc of last jump */ + int pc; /* pc of new jump */ luaK_dischargevars(fs, e); switch (e->k) { case VJMP: { - pc = e->u.info; + pc = e->u.info; /* already jump if true */ break; } case VNIL: case VFALSE: { @@ -688,29 +894,32 @@ void luaK_goiffalse (FuncState *fs, expdesc *e) { break; } default: { - pc = jumponcond(fs, e, 1); + pc = jumponcond(fs, e, 1); /* jump if true */ break; } } - luaK_concat(fs, &e->t, pc); /* insert last jump in 't' list */ - luaK_patchtohere(fs, e->f); + luaK_concat(fs, &e->t, pc); /* insert new jump in 't' list */ + luaK_patchtohere(fs, e->f); /* false list jumps to here (to go through) */ e->f = NO_JUMP; } +/* +** Code 'not e', doing constant folding. +*/ static void codenot (FuncState *fs, expdesc *e) { luaK_dischargevars(fs, e); switch (e->k) { case VNIL: case VFALSE: { - e->k = VTRUE; + e->k = VTRUE; /* true == not nil == not false */ break; } case VK: case VKFLT: case VKINT: case VTRUE: { - e->k = VFALSE; + e->k = VFALSE; /* false == not "x" == not 0.5 == not 1 == not true */ break; } case VJMP: { - invertjump(fs, e); + negatecondition(fs, e); break; } case VRELOCABLE: @@ -721,30 +930,32 @@ static void codenot (FuncState *fs, expdesc *e) { e->k = VRELOCABLE; break; } - default: { - lua_assert(0); /* cannot happen */ - break; - } + default: lua_assert(0); /* cannot happen */ } /* interchange true and false lists */ { int temp = e->f; e->f = e->t; e->t = temp; } - removevalues(fs, e->f); + removevalues(fs, e->f); /* values are useless when negated */ removevalues(fs, e->t); } +/* +** Create expression 't[k]'. 't' must have its final result already in a +** register or upvalue. +*/ void luaK_indexed (FuncState *fs, expdesc *t, expdesc *k) { - lua_assert(!hasjumps(t)); - t->u.ind.t = t->u.info; - t->u.ind.idx = luaK_exp2RK(fs, k); - t->u.ind.vt = (t->k == VUPVAL) ? VUPVAL - : check_exp(vkisinreg(t->k), VLOCAL); + lua_assert(!hasjumps(t) && (vkisinreg(t->k) || t->k == VUPVAL)); + t->u.ind.t = t->u.info; /* register or upvalue index */ + t->u.ind.idx = luaK_exp2RK(fs, k); /* R/K index for key */ + t->u.ind.vt = (t->k == VUPVAL) ? VUPVAL : VLOCAL; t->k = VINDEXED; } /* -** return false if folding can raise an error +** Return false if folding can raise an error. +** Bitwise operations need operands convertible to integers; division +** operations cannot have 0 as divisor. */ static int validop (int op, TValue *v1, TValue *v2) { switch (op) { @@ -761,7 +972,8 @@ static int validop (int op, TValue *v1, TValue *v2) { /* -** Try to "constant-fold" an operation; return 1 iff successful +** Try to "constant-fold" an operation; return 1 iff successful. +** (In this case, 'e1' has the final result.) */ static int constfolding (FuncState *fs, int op, expdesc *e1, expdesc *e2) { TValue v1, v2, res; @@ -772,7 +984,7 @@ static int constfolding (FuncState *fs, int op, expdesc *e1, expdesc *e2) { e1->k = VKINT; e1->u.ival = ivalue(&res); } - else { /* folds neither NaN nor 0.0 (to avoid collapsing with -0.0) */ + else { /* folds neither NaN nor 0.0 (to avoid problems with -0.0) */ lua_Number n = fltvalue(&res); if (luai_numisnan(n) || n == 0) return 0; @@ -784,81 +996,97 @@ static int constfolding (FuncState *fs, int op, expdesc *e1, expdesc *e2) { /* -** Code for binary and unary expressions that "produce values" -** (arithmetic operations, bitwise operations, concat, length). First -** try to do constant folding (only for numeric [arithmetic and -** bitwise] operations, which is what 'lua_arith' accepts). +** Emit code for unary expressions that "produce values" +** (everything but 'not'). +** Expression to produce final result will be encoded in 'e'. +*/ +static void codeunexpval (FuncState *fs, OpCode op, expdesc *e, int line) { + int r = luaK_exp2anyreg(fs, e); /* opcodes operate only on registers */ + freeexp(fs, e); + e->u.info = luaK_codeABC(fs, op, 0, r, 0); /* generate opcode */ + e->k = VRELOCABLE; /* all those operations are relocatable */ + luaK_fixline(fs, line); +} + + +/* +** Emit code for binary expressions that "produce values" +** (everything but logical operators 'and'/'or' and comparison +** operators). ** Expression to produce final result will be encoded in 'e1'. */ -static void codeexpval (FuncState *fs, OpCode op, - expdesc *e1, expdesc *e2, int line) { - lua_assert(op >= OP_ADD); - if (op <= OP_BNOT && constfolding(fs, op - OP_ADD + LUA_OPADD, e1, e2)) - return; /* result has been folded */ - else { - int o1, o2; - /* move operands to registers (if needed) */ - if (op == OP_UNM || op == OP_BNOT || op == OP_LEN) { /* unary op? */ - o2 = 0; /* no second expression */ - o1 = luaK_exp2anyreg(fs, e1); /* cannot operate on constants */ - } - else { /* regular case (binary operators) */ - o2 = luaK_exp2RK(fs, e2); /* both operands are "RK" */ - o1 = luaK_exp2RK(fs, e1); - } - if (o1 > o2) { /* free registers in proper order */ - freeexp(fs, e1); - freeexp(fs, e2); - } - else { - freeexp(fs, e2); - freeexp(fs, e1); - } - e1->u.info = luaK_codeABC(fs, op, 0, o1, o2); /* generate opcode */ - e1->k = VRELOCABLE; /* all those operations are relocable */ - luaK_fixline(fs, line); - } +static void codebinexpval (FuncState *fs, OpCode op, + expdesc *e1, expdesc *e2, int line) { + int rk1 = luaK_exp2RK(fs, e1); /* both operands are "RK" */ + int rk2 = luaK_exp2RK(fs, e2); + freeexps(fs, e1, e2); + e1->u.info = luaK_codeABC(fs, op, 0, rk1, rk2); /* generate opcode */ + e1->k = VRELOCABLE; /* all those operations are relocatable */ + luaK_fixline(fs, line); } -static void codecomp (FuncState *fs, OpCode op, int cond, expdesc *e1, - expdesc *e2) { - int o1 = luaK_exp2RK(fs, e1); - int o2 = luaK_exp2RK(fs, e2); - freeexp(fs, e2); - freeexp(fs, e1); - if (cond == 0 && op != OP_EQ) { - int temp; /* exchange args to replace by '<' or '<=' */ - temp = o1; o1 = o2; o2 = temp; /* o1 <==> o2 */ - cond = 1; +/* +** Emit code for comparisons. +** 'e1' was already put in R/K form by 'luaK_infix'. +*/ +static void codecomp (FuncState *fs, BinOpr opr, expdesc *e1, expdesc *e2) { + int rk1 = (e1->k == VK) ? RKASK(e1->u.info) + : check_exp(e1->k == VNONRELOC, e1->u.info); + int rk2 = luaK_exp2RK(fs, e2); + freeexps(fs, e1, e2); + switch (opr) { + case OPR_NE: { /* '(a ~= b)' ==> 'not (a == b)' */ + e1->u.info = condjump(fs, OP_EQ, 0, rk1, rk2); + break; + } + case OPR_GT: case OPR_GE: { + /* '(a > b)' ==> '(b < a)'; '(a >= b)' ==> '(b <= a)' */ + OpCode op = cast(OpCode, (opr - OPR_NE) + OP_EQ); + e1->u.info = condjump(fs, op, 1, rk2, rk1); /* invert operands */ + break; + } + default: { /* '==', '<', '<=' use their own opcodes */ + OpCode op = cast(OpCode, (opr - OPR_EQ) + OP_EQ); + e1->u.info = condjump(fs, op, 1, rk1, rk2); + break; + } } - e1->u.info = condjump(fs, op, cond, o1, o2); e1->k = VJMP; } +/* +** Aplly prefix operation 'op' to expression 'e'. +*/ void luaK_prefix (FuncState *fs, UnOpr op, expdesc *e, int line) { - expdesc e2; - e2.t = e2.f = NO_JUMP; e2.k = VKINT; e2.u.ival = 0; + static expdesc ef = {VKINT, {0}, NO_JUMP, NO_JUMP}; /* fake 2nd operand */ switch (op) { - case OPR_MINUS: case OPR_BNOT: case OPR_LEN: { - codeexpval(fs, cast(OpCode, (op - OPR_MINUS) + OP_UNM), e, &e2, line); + case OPR_MINUS: case OPR_BNOT: + if (constfolding(fs, op + LUA_OPUNM, e, &ef)) + break; + /* FALLTHROUGH */ + case OPR_LEN: + codeunexpval(fs, cast(OpCode, op + OP_UNM), e, line); break; - } case OPR_NOT: codenot(fs, e); break; default: lua_assert(0); } } +/* +** Process 1st operand 'v' of binary operation 'op' before reading +** 2nd operand. +*/ void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) { switch (op) { case OPR_AND: { - luaK_goiftrue(fs, v); + luaK_goiftrue(fs, v); /* go ahead only if 'v' is true */ break; } case OPR_OR: { - luaK_goiffalse(fs, v); + luaK_goiffalse(fs, v); /* go ahead only if 'v' is false */ break; } case OPR_CONCAT: { @@ -870,7 +1098,9 @@ void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) { case OPR_MOD: case OPR_POW: case OPR_BAND: case OPR_BOR: case OPR_BXOR: case OPR_SHL: case OPR_SHR: { - if (!tonumeral(v, NULL)) luaK_exp2RK(fs, v); + if (!tonumeral(v, NULL)) + luaK_exp2RK(fs, v); + /* else keep numeral, which may be folded with 2nd operand */ break; } default: { @@ -881,18 +1111,24 @@ void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) { } +/* +** Finalize code for binary operation, after reading 2nd operand. +** For '(a .. b .. c)' (which is '(a .. (b .. c))', because +** concatenation is right associative), merge second CONCAT into first +** one. +*/ void luaK_posfix (FuncState *fs, BinOpr op, expdesc *e1, expdesc *e2, int line) { switch (op) { case OPR_AND: { - lua_assert(e1->t == NO_JUMP); /* list must be closed */ + lua_assert(e1->t == NO_JUMP); /* list closed by 'luK_infix' */ luaK_dischargevars(fs, e2); luaK_concat(fs, &e2->f, e1->f); *e1 = *e2; break; } case OPR_OR: { - lua_assert(e1->f == NO_JUMP); /* list must be closed */ + lua_assert(e1->f == NO_JUMP); /* list closed by 'luK_infix' */ luaK_dischargevars(fs, e2); luaK_concat(fs, &e2->t, e1->t); *e1 = *e2; @@ -900,15 +1136,16 @@ void luaK_posfix (FuncState *fs, BinOpr op, } case OPR_CONCAT: { luaK_exp2val(fs, e2); - if (e2->k == VRELOCABLE && GET_OPCODE(getcode(fs, e2)) == OP_CONCAT) { - lua_assert(e1->u.info == GETARG_B(getcode(fs, e2))-1); + if (e2->k == VRELOCABLE && + GET_OPCODE(getinstruction(fs, e2)) == OP_CONCAT) { + lua_assert(e1->u.info == GETARG_B(getinstruction(fs, e2))-1); freeexp(fs, e1); - SETARG_B(getcode(fs, e2), e1->u.info); + SETARG_B(getinstruction(fs, e2), e1->u.info); e1->k = VRELOCABLE; e1->u.info = e2->u.info; } else { luaK_exp2nextreg(fs, e2); /* operand must be on the 'stack' */ - codeexpval(fs, OP_CONCAT, e1, e2, line); + codebinexpval(fs, OP_CONCAT, e1, e2, line); } break; } @@ -916,15 +1153,13 @@ void luaK_posfix (FuncState *fs, BinOpr op, case OPR_IDIV: case OPR_MOD: case OPR_POW: case OPR_BAND: case OPR_BOR: case OPR_BXOR: case OPR_SHL: case OPR_SHR: { - codeexpval(fs, cast(OpCode, (op - OPR_ADD) + OP_ADD), e1, e2, line); - break; - } - case OPR_EQ: case OPR_LT: case OPR_LE: { - codecomp(fs, cast(OpCode, op - OPR_EQ + OP_EQ), 1, e1, e2); + if (!constfolding(fs, op + LUA_OPADD, e1, e2)) + codebinexpval(fs, cast(OpCode, op + OP_ADD), e1, e2, line); break; } + case OPR_EQ: case OPR_LT: case OPR_LE: case OPR_NE: case OPR_GT: case OPR_GE: { - codecomp(fs, cast(OpCode, op - OPR_NE + OP_EQ), 0, e1, e2); + codecomp(fs, op, e1, e2); break; } default: lua_assert(0); @@ -932,15 +1167,25 @@ void luaK_posfix (FuncState *fs, BinOpr op, } +/* +** Change line information associated with current position. +*/ void luaK_fixline (FuncState *fs, int line) { fs->f->lineinfo[fs->pc - 1] = line; } +/* +** Emit a SETLIST instruction. +** 'base' is register that keeps table; +** 'nelems' is #table plus those to be stored now; +** 'tostore' is number of values (in registers 'base + 1',...) to add to +** table (or LUA_MULTRET to add up to stack top). +*/ void luaK_setlist (FuncState *fs, int base, int nelems, int tostore) { int c = (nelems - 1)/LFIELDS_PER_FLUSH + 1; int b = (tostore == LUA_MULTRET) ? 0 : tostore; - lua_assert(tostore != 0); + lua_assert(tostore != 0 && tostore <= LFIELDS_PER_FLUSH); if (c <= MAXARG_C) luaK_codeABC(fs, OP_SETLIST, base, b, c); else if (c <= MAXARG_Ax) { |