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First take on constant propagation

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This commit is contained in:
Roberto Ierusalimschy
2019-07-01 12:42:31 -03:00
parent 924bed7297
commit 8eca21c2e8
4 changed files with 73 additions and 26 deletions
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34
lparser.c
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@@ -206,6 +206,7 @@ static Vardesc *new_localvar (LexState *ls, TString *name) {
var = &dyd->actvar.arr[dyd->actvar.n++];
var->idx = cast(short, reg);
var->ro = 0;
setnilvalue(&var->val);
return var;
}
@@ -238,7 +239,7 @@ static LocVar *getlocvar (FuncState *fs, int i) {
** where that variable was defined. Return NULL if expression
** is neither a local variable nor an upvalue.
*/
static Vardesc *getvardesc (FuncState **fs, expdesc *e) {
Vardesc *luaY_getvardesc (FuncState **fs, const expdesc *e) {
if (e->k == VLOCAL)
return getlocalvardesc(*fs, e->u.var.idx);
else if (e->k != VUPVAL)
@@ -261,7 +262,7 @@ static Vardesc *getvardesc (FuncState **fs, expdesc *e) {
static void check_readonly (LexState *ls, expdesc *e) {
FuncState *fs = ls->fs;
Vardesc *vardesc = getvardesc(&fs, e);
Vardesc *vardesc = luaY_getvardesc(&fs, e);
if (vardesc && vardesc->ro) { /* is variable local and const? */
const char *msg = luaO_pushfstring(ls->L,
"attempt to assign to const variable '%s'",
@@ -1678,20 +1679,13 @@ static void commonlocalstat (LexState *ls) {
static void tocloselocalstat (LexState *ls, Vardesc *var) {
FuncState *fs = ls->fs;
var->ro = 1; /* to-be-closed variables are always read-only */
markupval(fs, fs->nactvar);
markupval(fs, fs->nactvar + 1);
fs->bl->insidetbc = 1; /* in the scope of a to-be-closed variable */
luaK_codeABC(fs, OP_TBC, fs->nactvar - 1, 0, 0);
luaK_codeABC(fs, OP_TBC, fs->nactvar, 0, 0);
}
static void attriblocalstat (LexState *ls) {
Vardesc *var;
TString *attr = str_checkname(ls);
testnext(ls, '>');
var = new_localvar(ls, str_checkname(ls));
checknext(ls, '=');
exp1(ls);
adjustlocalvars(ls, 1);
static void checkattrib (LexState *ls, TString *attr, Vardesc *var) {
if (strcmp(getstr(attr), "const") == 0)
var->ro = 1; /* set variable as read-only */
else if (strcmp(getstr(attr), "toclose") == 0)
@@ -1702,6 +1696,22 @@ static void attriblocalstat (LexState *ls) {
}
static void attriblocalstat (LexState *ls) {
FuncState *fs = ls->fs;
Vardesc *var;
expdesc e;
TString *attr = str_checkname(ls);
testnext(ls, '>');
var = new_localvar(ls, str_checkname(ls));
checknext(ls, '=');
expr(ls, &e);
checkattrib(ls, attr, var);
luaK_tonumeral(fs, &e, &var->val);
luaK_exp2nextreg(fs, &e);
adjustlocalvars(ls, 1);
}
static void localstat (LexState *ls) {
/* stat -> LOCAL NAME {',' NAME} ['=' explist]
| LOCAL *toclose NAME '=' exp */