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>
This commit is contained in:
Mike Frysinger 2012-04-03 03:37:26 +00:00
parent b1c0804b2e
commit 23916fffce
2 changed files with 13 additions and 4 deletions

View File

@ -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.

View File

@ -72,10 +72,13 @@ 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++;
if (fmt != str)
if (fwrite (str, 1, fmt - str, fp))
{
/* Ignore. */
}
if (*fmt == '%')