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 (file)
--- 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 (file)
--- 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 == '%')
        {