awk: document which hashes are used at what state (parse/execute)

We can free them after they are no longer needed.
(Currently, being a NOEXEC applet is much larger waste of memory
for the case of long-running awk script).

function                                             old     new   delta
awk_main                                             831     827      -4

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 20 insertions, 10 deletions

diff --git a/editors/awk.c b/editors/awk.c
index ce860dc04..6142144bb 100644
--- a/editors/awk.c
+++ b/editors/awk.c
@@ -527,7 +527,10 @@ struct globals {
         chain *seq;
         node *break_ptr, *continue_ptr;
         rstream *iF;
-        xhash *vhash, *ahash, *fdhash, *fnhash;
+        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 */
         const char *g_progname;
         int g_lineno;
         int nfields;
@@ -1719,6 +1722,7 @@ static void parse_program(char *p)
                         debug_printf_parse("%s: TC_FUNCDECL\n", __func__);
                         next_token(TC_FUNCTION);
                         f = newfunc(t_string);
+//FIXME: dup check: functions can't be redefined, this is not ok: awk 'func f(){}; func f(){}'
                         f->body.first = NULL;
                         f->nargs = 0;
                         /* func arg list: comma sep list of args, and a close paren */
@@ -3389,12 +3393,8 @@ int awk_main(int argc UNUSED_PARAM, char **argv)
         if (ENABLE_LOCALE_SUPPORT)
                 setlocale(LC_NUMERIC, "C");
 
-        vhash = hash_init();
-        ahash = hash_init();
-        fdhash = hash_init();
-        fnhash = hash_init();
-
         /* initialize variables */
+        vhash = hash_init();
         {
                 char *vnames = (char *)vNames; /* cheat */
                 char *vvalues = (char *)vValues;
@@ -3416,10 +3416,6 @@ int awk_main(int argc UNUSED_PARAM, char **argv)
         handle_special(intvar[FS]);
         handle_special(intvar[RS]);
 
-        newfile("/dev/stdin")->F = stdin;
-        newfile("/dev/stdout")->F = stdout;
-        newfile("/dev/stderr")->F = stderr;
-
         /* Huh, people report that sometimes environ is NULL. Oh well. */
         if (environ) {
                 char **envp;
@@ -3449,6 +3445,10 @@ int awk_main(int argc UNUSED_PARAM, char **argv)
                 if (!is_assignment(llist_pop(&list_v)))
                         bb_show_usage();
         }
+
+        /* Parse all supplied programs */
+        fnhash = hash_init();
+        ahash = hash_init();
         while (list_f) {
                 int fd;
                 char *s;
@@ -3471,6 +3471,11 @@ 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 */
 
         /* fill in ARGV array */
         setari_u(intvar[ARGV], 0, "awk");
@@ -3479,6 +3484,11 @@ int awk_main(int argc UNUSED_PARAM, char **argv)
                 setari_u(intvar[ARGV], ++i, *argv++);
         setvar_i(intvar[ARGC], i + 1);
 
+        fdhash = hash_init();
+        newfile("/dev/stdin")->F = stdin;
+        newfile("/dev/stdout")->F = stdout;
+        newfile("/dev/stderr")->F = stderr;
+
         zero_out_var(&tv);
         evaluate(beginseq.first, &tv);
         if (!mainseq.first && !endseq.first)