[builtins][test] Avoid unportable mmap call in clear_cache_test.c
Within the last two weeks, the Builtins-*-sunos :: clear_cache_test.c started to FAIL
on Solaris. Running it under truss shows
mmap(0x00000000, 128, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANON, 0, 0) Err#22 EINVAL
_exit(1)
While there are several possible reasons mmap can return EINVAL on Solaris, it turns
out it's this one (from mmap(2)):
MAP_ANON was specified, but the file descriptor was not
-1.
And indeed even the Linux mmap(2) documents this as unportable:
MAP_ANONYMOUS
The mapping is not backed by any file; its contents are initial‐
ized to zero. The fd argument is ignored; however, some imple‐
mentations require fd to be -1 if MAP_ANONYMOUS (or MAP_ANON) is
specified, and portable applications should ensure this. The
This patch follows this advise. Tested on x86_64-pc-linux-gnu, amd64-pc-solaris2.11
and sparcv9-sun-solaris2.11.
Differential Revision: https://reviews.llvm.org/D68455
llvm-svn: 375490