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>
+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.
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 == '%')
{