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awk: free unused parsing structures after parse is done

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function                                             old     new   delta
hash_clear                                             -      90     +90
awk_main                                             827     849     +22
clear_array                                           90       -     -90
------------------------------------------------------------------------------
(add/remove: 1/1 grow/shrink: 1/0 up/down: 112/-90)            Total: 22 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2021-06-29 18:33:25 +02:00
parent 21fbee2e87
commit b3c91a127f
1 changed files with 47 additions and 27 deletions
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74
editors/awk.c
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@ -530,7 +530,8 @@ struct globals {
xhash *ahash; /* argument names, used only while parsing function bodies */
xhash *fnhash; /* function names, used only in parsing stage */
xhash *vhash; /* variables and arrays */
xhash *fdhash; /* file objects, used only in execution stage */
//xhash *fdhash; /* file objects, used only in execution stage */
//we are reusing ahash as fdhash, via define (see later)
const char *g_progname;
int g_lineno;
int nfields;
@ -592,10 +593,13 @@ struct globals2 {
#define break_ptr (G1.break_ptr )
#define continue_ptr (G1.continue_ptr)
#define iF (G1.iF )
#define vhash (G1.vhash )
#define ahash (G1.ahash )
#define fdhash (G1.fdhash )
#define fnhash (G1.fnhash )
#define vhash (G1.vhash )
#define fdhash ahash
//^^^^^^^^^^^^^^^^^^ ahash is cleared after every function parsing,
// and ends up empty after parsing phase. Thus, we can simply reuse it
// for fdhash in execution stage.
#define g_progname (G1.g_progname )
#define g_lineno (G1.g_lineno )
#define nfields (G1.nfields )
@ -682,6 +686,33 @@ static xhash *hash_init(void)
return newhash;
}
static void hash_clear(xhash *hash)
{
unsigned i;
hash_item *hi, *thi;
for (i = 0; i < hash->csize; i++) {
hi = hash->items[i];
while (hi) {
thi = hi;
hi = hi->next;
free(thi->data.v.string);
free(thi);
}
hash->items[i] = NULL;
}
hash->glen = hash->nel = 0;
}
#if 0 //UNUSED
static void hash_free(xhash *hash)
{
hash_clear(hash);
free(hash->items);
free(hash);
}
#endif
/* find item in hash, return ptr to data, NULL if not found */
static void *hash_search(xhash *hash, const char *name)
{
@ -869,23 +900,7 @@ static xhash *iamarray(var *v)
return a->x.array;
}
static void clear_array(xhash *array)
{
unsigned i;
hash_item *hi, *thi;
for (i = 0; i < array->csize; i++) {
hi = array->items[i];
while (hi) {
thi = hi;
hi = hi->next;
free(thi->data.v.string);
free(thi);
}
array->items[i] = NULL;
}
array->glen = array->nel = 0;
}
#define clear_array(array) hash_clear(array)
/* clear a variable */
static var *clrvar(var *v)
@ -1742,7 +1757,7 @@ static void parse_program(char *p)
}
seq = &f->body;
chain_group();
clear_array(ahash);
hash_clear(ahash);
} else if (tclass & TS_OPSEQ) {
debug_printf_parse("%s: TS_OPSEQ\n", __func__);
rollback_token();
@ -3471,11 +3486,16 @@ int awk_main(int argc UNUSED_PARAM, char **argv)
bb_show_usage();
parse_program(*argv++);
}
//free_hash(ahash) // ~250 bytes, arg names, used only during parse of function bodies
//ahash = NULL; // debug
//free_hash(fnhash) // ~250 bytes, used only for function names
//fnhash = NULL; // debug
/* parsing done, on to executing */
/* Free unused parse structures */
//hash_free(fnhash); // ~250 bytes when empty, used only for function names
//^^^^^^^^^^^^^^^^^ does not work, hash_clear() inside SEGVs
// (IOW: hash_clear() assumes it's a hash of variables. fnhash is not).
free(fnhash->items);
free(fnhash);
fnhash = NULL; // debug
//hash_free(ahash); // empty after parsing, will reuse as fdhash instead of freeing
/* Parsing done, on to executing */
/* fill in ARGV array */
setari_u(intvar[ARGV], 0, "awk");
@ -3484,7 +3504,7 @@ int awk_main(int argc UNUSED_PARAM, char **argv)
setari_u(intvar[ARGV], ++i, *argv++);
setvar_i(intvar[ARGC], i + 1);
fdhash = hash_init();
//fdhash = ahash - done via define
newfile("/dev/stdin")->F = stdin;
newfile("/dev/stdout")->F = stdout;
newfile("/dev/stderr")->F = stderr;