[klibc] Re: Warnings building dash

[Herbert Xu]

On Tue, Mar 28, 2006 at 07:42:17AM +1100, herbert wrote:
> On Mon, Mar 27, 2006 at 08:21:12AM -0800, H. Peter Anvin wrote:
> > 
> > That's not going to fly, though, for merging upstream with the kernel.
> 
> OK I'll send you a patch then.

Turns out that we can use alloca to get rid of the setjmp/longjmp
altogether.  This makes dash 1% smaller.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert at gondor.apana.org.au>
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--
diff --git a/parser.c b/parser.c
index c62a950..4362f6a 100644
--- a/parser.c
+++ b/parser.c
@@ -32,6 +32,7 @@
  * SUCH DAMAGE.
  */
 
+#include <alloca.h>
 #include <stdlib.h>
 
 #include "shell.h"
@@ -76,7 +77,6 @@
 
 
 struct heredoc *heredoclist;	/* list of here documents to read */
-int parsebackquote;		/* nonzero if we are inside backquotes */
 int doprompt;			/* if set, prompt the user */
 int needprompt;			/* true if interactive and at start of line */
 int lasttoken;			/* last token read */
@@ -847,21 +847,8 @@
 	int dqvarnest;	/* levels of variables expansion within double quotes */
 	int oldstyle;
 	char const *prevsyntax;	/* syntax before arithmetic */
-#if __GNUC__
-	/* Avoid longjmp clobbering */
-	(void) &out;
-	(void) &quotef;
-	(void) &dblquote;
-	(void) &varnest;
-	(void) &arinest;
-	(void) &parenlevel;
-	(void) &dqvarnest;
-	(void) &oldstyle;
-	(void) &prevsyntax;
-	(void) &syntax;
-#endif
-
-	startlinno = plinno;
+
+	startlinno = plinno;
 	dblquote = 0;
 	if (syntax == DQSYNTAX)
 		dblquote = 1;
@@ -1019,7 +1006,7 @@
 endword:
 	if (syntax == ARISYNTAX)
 		synerror("Missing '))'");
-	if (syntax != BASESYNTAX && ! parsebackquote && eofmark == NULL)
+	if (syntax != BASESYNTAX && eofmark == NULL)
 		synerror("Unterminated quoted string");
 	if (varnest != 0) {
 		startlinno = plinno;
@@ -1263,35 +1250,17 @@
 
 parsebackq: {
 	struct nodelist **nlpp;
-	int savepbq;
-	union node *n;
-	char *volatile str;
-	struct jmploc jmploc;
-	struct jmploc *volatile savehandler;
+	union node *n;
+	char *str;
 	size_t savelen;
 	int saveprompt;
-#ifdef __GNUC__
-	(void) &saveprompt;
-#endif
-
-	savepbq = parsebackquote;
-	if (setjmp(jmploc.loc)) {
-		if (str)
-			ckfree(str);
-		parsebackquote = 0;
-		handler = savehandler;
-		longjmp(handler->loc, 1);
-	}
-	INTOFF;
+
 	str = NULL;
 	savelen = out - (char *)stackblock();
 	if (savelen > 0) {
-		str = ckmalloc(savelen);
+		str = alloca(savelen);
 		memcpy(str, stackblock(), savelen);
 	}
-	savehandler = handler;
-	handler = &jmploc;
-	INTON;
         if (oldstyle) {
                 /* We must read until the closing backquote, giving special
                    treatment to some slashes, and then push the string and
@@ -1360,7 +1329,6 @@
 		nlpp = &(*nlpp)->next;
 	*nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 	(*nlpp)->next = NULL;
-	parsebackquote = oldstyle;
 
 	if (oldstyle) {
 		saveprompt = doprompt;
@@ -1391,13 +1359,7 @@
 	if (str) {
 		memcpy(out, str, savelen);
 		STADJUST(savelen, out);
-		INTOFF;
-		ckfree(str);
-		str = NULL;
-		INTON;
-	}
-	parsebackquote = savepbq;
-	handler = savehandler;
+	}
 	if (arinest || dblquote)
 		USTPUTC(CTLBACKQ | CTLQUOTE, out);
 	else