isolate all knowledge of the area-based allocator from the rest of the code

cost: bss -= (0, 0, 16, 16); text += (520, 504, 516, 480)
[ gcc,pcc X full,small ]

alloc.c

@@ -29,32 +29,39 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/alloc.c,v 1.9 2008/11/11 23:50:28 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/alloc.c,v 1.10 2008/11/12 00:27:54 tg Exp $");
 
 struct link {
 	struct link *prev;
 	struct link *next;
 };
 
-struct TArea aperm;
+struct TArea {
+	struct link *freelist;	/* free list */
+};
 
 PArea
-ainit(PArea ap)
+anew(void)
 {
+	PArea ap;
+
+	if ((ap = malloc(sizeof (struct TArea))) == NULL)
+		internal_errorf("unable to allocate memory");
 	ap->freelist = NULL;
 	return (ap);
 }
 
 void
-afreeall(PArea ap)
+adelete(PArea *pap)
 {
 	struct link *l, *l2;
 
-	for (l = ap->freelist; l != NULL; l = l2) {
+	for (l = (*pap)->freelist; l != NULL; l = l2) {
 		l2 = l->next;
 		free(l);
 	}
-	ap->freelist = NULL;
+	free(*pap);
+	*pap = NULL;
 }
 
 #define L2P(l)	( (void *)(((char *)(l)) + sizeof (struct link)) )

edit.c

@@ -5,7 +5,7 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/edit.c,v 1.142 2008/11/11 23:50:28 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/edit.c,v 1.143 2008/11/12 00:27:54 tg Exp $");
 
 /* tty driver characters we are interested in */
 typedef struct {
@@ -960,8 +960,7 @@ utf_wctomb(char *dst, unsigned int wc)
 
 /* +++ emacs editing mode +++ */
 
-static struct TArea aedit;
-#define	AEDIT	&aedit		/* area for kill ring and macro defns */
+static PArea AEDIT;		/* area for kill ring and macro defns */
 
 #define	MKCTRL(x)	((x) == '?' ? 0x7F : (x) & 0x1F)	/* ASCII */
 #define	UNCTRL(x)	((x) ^ 0x40)				/* ASCII */
@@ -2682,7 +2681,7 @@ x_init_emacs(void)
 {
 	int i, j;
 
-	ainit(AEDIT);
+	AEDIT = anew();
 	x_nextcmd = -1;
 
 	x_tab = (unsigned char (*)[X_TABSZ])alloc(sizeofN(*x_tab, X_NTABS), AEDIT);

funcs.c

@@ -5,7 +5,7 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/funcs.c,v 1.90 2008/10/28 14:32:40 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/funcs.c,v 1.91 2008/11/12 00:27:55 tg Exp $");
 
 /* A leading = means assignments before command are kept;
  * a leading * means a POSIX special builtin;
@@ -2111,10 +2111,10 @@ c_set(const char **wp)
 		owp = wp += argi - 1;
 		wp[0] = l->argv[0]; /* save $0 */
 		while (*++wp != NULL)
-			strdupx(*wp, *wp, &l->area);
+			strdupx(*wp, *wp, l->areap);
 		l->argc = wp - owp - 1;
 		l->argv = (const char **)alloc(sizeofN(char *, l->argc+2),
-		     &l->area);
+		     l->areap);
 		for (wp = l->argv; (*wp++ = *owp++) != NULL; )
 			;
 	}

main.c

@@ -13,7 +13,7 @@
 #include <locale.h>
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/main.c,v 1.107 2008/11/11 23:50:30 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/main.c,v 1.108 2008/11/12 00:27:56 tg Exp $");
 
 extern char **environ;
 
@@ -22,7 +22,7 @@ extern uid_t kshuid;
 extern gid_t kshgid, kshegid;
 #endif
 
-static void reclaim(void);
+static void reclaim(bool);
 static void remove_temps(struct temp *);
 
 static const char initifs[] = "IFS= \t\n";
@@ -87,11 +87,11 @@ main(int argc, const char *argv[])
 	}
 	kshname = *argv;
 
-	ainit(&aperm);		/* initialise permanent Area */
+	APERM = anew();		/* initialise permanent Area */
 
 	/* set up base environment */
 	env.type = E_NONE;
-	ainit(&env.area);
+	env.areap = anew();
 	newblock();		/* set up global l->vars and l->funs */
 
 	/* Do this first so output routines (eg, errorf, shellf) can work */
@@ -563,7 +563,7 @@ shell(Source * volatile s, volatile int toplevel)
 		if (t != NULL && t->type != TEOF && interactive && really_exit)
 			really_exit = 0;
 
-		reclaim();
+		reclaim(false);
 	}
 	quitenv(NULL);
 	source = old_source;
@@ -610,7 +610,7 @@ newenv(int type)
 	ep = (struct env *)alloc(sizeof (*ep), ATEMP);
 	ep->type = type;
 	ep->flags = 0;
-	ainit(&ep->area);
+	ep->areap = anew();
 	ep->loc = e->loc;
 	ep->savefd = NULL;
 	ep->oenv = e;
@@ -662,12 +662,12 @@ quitenv(struct shf *shf)
 		}
 		if (shf)
 			shf_close(shf);
-		reclaim();
+		reclaim(true);
 		exit(exstat);
 	}
 	if (shf)
 		shf_close(shf);
-	reclaim();
+	reclaim(true);
 
 	e = e->oenv;
 	afree(ep, ATEMP);
@@ -691,7 +691,7 @@ cleanup_parents_env(void)
 			for (fd = 0; fd < NUFILE; fd++)
 				if (ep->savefd[fd] > 0)
 					close(ep->savefd[fd]);
-			afree(ep->savefd, &ep->area);
+			afree(ep->savefd, ep->areap);
 			ep->savefd = NULL;
 		}
 	}
@@ -710,11 +710,13 @@ cleanup_proc_env(void)
 
 /* remove temp files and free ATEMP Area */
 static void
-reclaim(void)
+reclaim(bool finish)
 {
 	remove_temps(e->temps);
 	e->temps = NULL;
-	afreeall(&e->area);
+	adelete(&e->areap);
+	if (!finish)
+		e->areap = anew();
 }
 
 static void

sh.h

@@ -103,7 +103,7 @@
 #define __SCCSID(x)	__IDSTRING(sccsid,x)
 
 #ifdef EXTERN
-__RCSID("$MirOS: src/bin/mksh/sh.h,v 1.253 2008/11/11 23:50:30 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/sh.h,v 1.254 2008/11/12 00:27:56 tg Exp $");
 #endif
 #define MKSH_VERSION "R36 2008/11/10"
 
@@ -389,20 +389,15 @@ char *ucstrstr(char *, const char *);
 #define MKSH_NOVI
 #endif
 
-struct TArea {
-	struct link *freelist;	/* free list */
-};
 typedef struct TArea *PArea;
-
-extern struct TArea aperm;		/* permanent object space */
-#define APERM	&aperm
-#define ATEMP	&e->area
+EXTERN PArea APERM;			/* permanent object space */
+#define ATEMP	e->areap
 
 /*
  * parsing & execution environment
  */
 extern struct env {
-	struct TArea area;	/* temporary allocation area */
+	PArea areap;		/* temporary allocation area */
 	struct block *loc;	/* local variables and functions */
 	short *savefd;		/* original redirected fds */
 	struct env *oenv;	/* link to previous environment */
@@ -857,7 +852,7 @@ struct arg_info {
  * activation record for function blocks
  */
 struct block {
-	struct TArea area;	/* area to allocate things */
+	PArea areap;		/* area to allocate things */
 	const char **argv;
 	int argc;
 	int flags;		/* see BF_* */
@@ -1253,8 +1248,8 @@ EXTERN int histsize;	/* history size */
 EXTERN struct timeval j_usrtime, j_systime;
 
 /* alloc.c */
-PArea ainit(PArea);
-void afreeall(PArea);
+PArea anew(void);		/* cannot fail */
+void adelete(PArea *);
 void *alloc(size_t, PArea);	/* cannot fail */
 void *aresize(void *, size_t, PArea);
 void afree(void *, PArea);	/* can take NULL */

var.c

@@ -2,7 +2,7 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/var.c,v 1.58 2008/10/28 14:32:43 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/var.c,v 1.59 2008/11/12 00:27:57 tg Exp $");
 
 /*
  * Variables
@@ -39,7 +39,7 @@ newblock(void)
 
 	l = (struct block *)alloc(sizeof (struct block), ATEMP);
 	l->flags = 0;
-	ainit(&l->area); /* todo: could use e->area (l->area => l->areap) */
+	l->areap = anew();	/* TODO: could use e->area */
 	if (!e->loc) {
 		l->argc = 0;
 		l->argv = empty;
@@ -48,8 +48,8 @@ newblock(void)
 		l->argv = e->loc->argv;
 	}
 	l->exit = l->error = NULL;
-	ktinit(&l->vars, &l->area, 0);
-	ktinit(&l->funs, &l->area, 0);
+	ktinit(&l->vars, l->areap, 0);
+	ktinit(&l->funs, l->areap, 0);
 	l->next = e->loc;
 	e->loc = l;
 }
@@ -74,7 +74,7 @@ popblock(void)
 		}
 	if (l->flags & BF_DOGETOPTS)
 		user_opt = l->getopts_state;
-	afreeall(&l->area);
+	adelete(&l->areap);
 	afree(l, ATEMP);
 }