From b12b635a9052240538daf0d049834b60aa64b435 Mon Sep 17 00:00:00 2001 From: Roberto Ierusalimschy Date: Mon, 4 Jan 2016 11:40:57 -0200 Subject: more refactoring --- lcode.c | 191 ++++++++++++++++++++++++++++++++-------------------------------- 1 file changed, 97 insertions(+), 94 deletions(-) diff --git a/lcode.c b/lcode.c index a15e8dcc..a274e974 100644 --- a/lcode.c +++ b/lcode.c @@ -1,5 +1,5 @@ /* -** $Id: lcode.c,v 2.103 2015/11/19 19:16:22 roberto Exp roberto $ +** $Id: lcode.c,v 2.106 2015/12/18 13:53:36 roberto Exp roberto $ ** Code generator for Lua ** See Copyright Notice in lua.h */ @@ -400,6 +400,24 @@ 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 @@ -531,33 +549,35 @@ void luaK_setoneret (FuncState *fs, expdesc *e) { /* -** Ensure that expression 'e' has a value somewhere (either it -** is a constant or result is in a register). +** Ensure that expression 'e' is not a variable. */ void luaK_dischargevars (FuncState *fs, expdesc *e) { switch (e->k) { - case VLOCAL: { + 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; } @@ -731,36 +751,22 @@ 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) { /* handle constants */ - 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; - } - /* FALLTHROUGH */ - 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 */ @@ -988,65 +994,62 @@ static int constfolding (FuncState *fs, int op, expdesc *e1, expdesc *e2) { /* -** Emit code for binary and unary expressions that "produce values" -** (everything but logical operators 'and', 'or' and comparison +** 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). -** First try to do constant folding (only for numeric [arithmetic and -** bitwise] operations, which is what 'lua_arith' accepts). Expression -** to produce final result will be encoded in 'e1'. -** (The "free registers in proper order" reason is tricky: because -** expression evaluation can be delayed, the final numbering for -** registers in 'e1' and 'e2' depends on how each one was delayed.) +** 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_ADD <= op && op <= OP_CONCAT); - 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 relocatable */ - 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); } /* ** Emit code for comparisons. -** Code will jump if result equals 'cond' ('cond' true <=> code will -** jump if result is true). +** 'e1' was already put in R/K form by 'luaK_infix'. */ -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); - lua_assert(OP_EQ <= op && op <= OP_LE); /* comparison operation */ - 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; +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; } @@ -1055,13 +1058,15 @@ static void codecomp (FuncState *fs, OpCode op, int cond, expdesc *e1, ** Aplly prefix operation 'op' to expression 'e'. */ void luaK_prefix (FuncState *fs, UnOpr op, expdesc *e, int line) { - expdesc e2; /* fake 2nd operand */ - 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; + /* else go through */ + case OPR_LEN: + codeunexpval(fs, cast(OpCode, op + OP_UNM), e, line); break; - } case OPR_NOT: codenot(fs, e); break; default: lua_assert(0); } @@ -1137,7 +1142,7 @@ void luaK_posfix (FuncState *fs, BinOpr op, } 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; } @@ -1145,15 +1150,13 @@ 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); -- cgit v1.2.3-55-g6feb