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new method to handle tests without values (negative values)

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This commit is contained in:
Roberto Ierusalimschy
2005-08-29 17:49:21 -03:00
parent 3390f9a35a
commit 3b19af44b0
6 changed files with 58 additions and 40 deletions
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69
lcode.c
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@@ -1,5 +1,5 @@
/*
** $Id: lcode.c,v 2.14 2005/06/07 18:53:45 roberto Exp roberto $
** $Id: lcode.c,v 2.15 2005/08/17 18:32:09 roberto Exp $
** Code generator for Lua
** See Copyright Notice in lua.h
*/
@@ -53,6 +53,11 @@ int luaK_jump (FuncState *fs) {
}
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);
@@ -101,49 +106,50 @@ static Instruction *getjumpcontrol (FuncState *fs, int pc) {
** 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, int cond) {
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_TEST || GETARG_C(i) != cond) return 1;
if (GET_OPCODE(i) != OP_TESTSET) return 1;
}
return 0; /* not found */
}
static void patchtestreg (Instruction *i, int reg) {
if (reg == NO_REG) reg = GETARG_B(*i);
SETARG_A(*i, reg);
if (reg != NO_REG)
SETARG_A(*i, reg);
else /* no register to put value; change TESTSET to TEST */
*i = CREATE_ABC(OP_TEST, GETARG_B(*i), 0, GETARG_C(*i));
}
static void patchlistaux (FuncState *fs, int list,
int ttarget, int treg, int ftarget, int freg, int dtarget) {
static void removevalues (FuncState *fs, int list) {
for (; list != NO_JUMP; list = getjump(fs, list)) {
Instruction *i = getjumpcontrol(fs, list);
if (GET_OPCODE(*i) == OP_TESTSET)
patchtestreg(i, NO_REG);
}
}
static void patchlistaux (FuncState *fs, int list, int vtarget, int reg,
int dtarget) {
while (list != NO_JUMP) {
int next = getjump(fs, list);
Instruction *i = getjumpcontrol(fs, list);
if (GET_OPCODE(*i) != OP_TEST) {
lua_assert(dtarget != NO_JUMP);
if (GET_OPCODE(*i) == OP_TESTSET) {
patchtestreg(i, reg);
fixjump(fs, list, vtarget);
}
else
fixjump(fs, list, dtarget); /* jump to default target */
}
else {
if (GETARG_C(*i)) {
lua_assert(ttarget != NO_JUMP);
patchtestreg(i, treg);
fixjump(fs, list, ttarget);
}
else {
lua_assert(ftarget != NO_JUMP);
patchtestreg(i, freg);
fixjump(fs, list, ftarget);
}
}
list = next;
}
}
static void dischargejpc (FuncState *fs) {
patchlistaux(fs, fs->jpc, fs->pc, NO_REG, fs->pc, NO_REG, fs->pc);
patchlistaux(fs, fs->jpc, fs->pc, NO_REG, fs->pc);
fs->jpc = NO_JUMP;
}
@@ -153,7 +159,7 @@ void luaK_patchlist (FuncState *fs, int list, int target) {
luaK_patchtohere(fs, list);
else {
lua_assert(target < fs->pc);
patchlistaux(fs, list, target, NO_REG, target, NO_REG, target);
patchlistaux(fs, list, target, NO_REG, target);
}
}
@@ -373,7 +379,7 @@ static void exp2reg (FuncState *fs, expdesc *e, int reg) {
int final; /* position after whole expression */
int p_f = NO_JUMP; /* position of an eventual LOAD false */
int p_t = NO_JUMP; /* position of an eventual LOAD true */
if (need_value(fs, e->t, 1) || need_value(fs, e->f, 0)) {
if (need_value(fs, e->t) || need_value(fs, e->f)) {
int fj = NO_JUMP; /* first jump (over LOAD ops.) */
if (e->k != VJMP)
fj = luaK_jump(fs);
@@ -382,8 +388,8 @@ static void exp2reg (FuncState *fs, expdesc *e, int reg) {
luaK_patchtohere(fs, fj);
}
final = luaK_getlabel(fs);
patchlistaux(fs, e->f, p_f, NO_REG, final, reg, p_f);
patchlistaux(fs, e->t, final, reg, p_t, NO_REG, p_t);
patchlistaux(fs, e->f, final, reg, p_f);
patchlistaux(fs, e->t, final, reg, p_t);
}
e->f = e->t = NO_JUMP;
e->info = reg;
@@ -492,7 +498,8 @@ void luaK_self (FuncState *fs, expdesc *e, expdesc *key) {
static void invertjump (FuncState *fs, expdesc *e) {
Instruction *pc = getjumpcontrol(fs, e->info);
lua_assert(testTMode(GET_OPCODE(*pc)) && GET_OPCODE(*pc) != OP_TEST);
lua_assert(testTMode(GET_OPCODE(*pc)) && GET_OPCODE(*pc) != OP_TESTSET &&
GET_OPCODE(*pc) != OP_TEST);
SETARG_A(*pc, !(GETARG_A(*pc)));
}
@@ -502,13 +509,13 @@ static int jumponcond (FuncState *fs, expdesc *e, int cond) {
Instruction ie = getcode(fs, e);
if (GET_OPCODE(ie) == OP_NOT) {
fs->pc--; /* remove previous OP_NOT */
return condjump(fs, OP_TEST, NO_REG, GETARG_B(ie), !cond);
return condjump(fs, OP_TEST, GETARG_B(ie), 0, !cond);
}
/* else go through */
}
discharge2anyreg(fs, e);
freeexp(fs, e);
return condjump(fs, OP_TEST, NO_REG, e->info, cond);
return condjump(fs, OP_TESTSET, NO_REG, e->info, cond);
}
@@ -597,6 +604,8 @@ static void codenot (FuncState *fs, expdesc *e) {
}
/* interchange true and false lists */
{ int temp = e->f; e->f = e->t; e->t = temp; }
removevalues(fs, e->f);
removevalues(fs, e->t);
}