From: Mike Frysinger <vapier@gentoo.org>
Date: Tue, 3 Apr 2012 03:37:26 +0000 (+0000)
Subject: ld: optimize vfinfo output slightly
X-Git-Tag: cygwin-1_7_14-release~82
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=23916fffce6bac40347fc5a061c9e073e462f943;p=external%2Fbinutils.git

ld: optimize vfinfo output slightly

ld atm ends up calling the write() syscall on every char when displaying
an error message.  For example:
$ echo 'main(){foo();}' | strace -f -ewrite gcc -x c -o /dev/null -
...
[pid 13035] write(2, ":", 1)            = 1
[pid 13035] write(2, " ", 1)            = 1
[pid 13035] write(2, "I", 1)            = 1
[pid 13035] write(2, "n", 1)            = 1
[pid 13035] write(2, " ", 1)            = 1
[pid 13035] write(2, "f", 1)            = 1
[pid 13035] write(2, "u", 1)            = 1
[pid 13035] write(2, "n", 1)            = 1
[pid 13035] write(2, "c", 1)            = 1
[pid 13035] write(2, "t", 1)            = 1
[pid 13035] write(2, "i", 1)            = 1
[pid 13035] write(2, "o", 1)            = 1
[pid 13035] write(2, "n", 1)            = 1
[pid 13035] write(2, " ", 1)            = 1
[pid 13035] write(2, "`", 1)            = 1
...

That's just to write ": In function `main':".  A slight optimization in
the vfinfo() func gives a much more reasonable syscall footprint:
...
write(2, ": In function `", 15)         = 15
...

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
---

diff --git a/ld/ChangeLog b/ld/ChangeLog
index 9801bda..203f986 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,9 @@
+2012-04-02  Mike Frysinger  <vapier@gentoo.org>
+
+	* ldmisc.c (vfinfo): Assign new local str to fmt.  Delete
+	putc call.  If str and fmt are different, call fwrite on
+	the difference.
+
 2012-03-30  Nick Clifton  <nickc@redhat.com>
 
 	* po/vi.po: Updated Vietnamese translation.
diff --git a/ld/ldmisc.c b/ld/ldmisc.c
index 5112c71..ca1896f 100644
--- a/ld/ldmisc.c
+++ b/ld/ldmisc.c
@@ -72,11 +72,14 @@ vfinfo (FILE *fp, const char *fmt, va_list arg, bfd_boolean is_warning)
 
   while (*fmt != '\0')
     {
+      const char *str = fmt;
       while (*fmt != '%' && *fmt != '\0')
-	{
-	  putc (*fmt, fp);
-	  fmt++;
-	}
+	fmt++;
+      if (fmt != str)
+	if (fwrite (str, 1, fmt - str, fp))
+	  {
+	    /* Ignore.  */
+	  }
 
       if (*fmt == '%')
 	{