On 1/3/2026 9:43 PM, Kalvis Duckmanton wrote:
Hi Jeff,
On 6/12/25 16:14, Jeff Law wrote:
On 11/26/25 7:45 PM, Kalvis Duckmanton wrote:
On 26/11/25 11:15, Jeff Law wrote:
On 11/18/25 7:41 PM, Kalvis Duckmanton wrote:
Hi!
The PCH use_address hooks for NetBSD hosts have not yet been
updated to allow compiled headers to be loaded at an address
different from their preferred address.
This change updates host-netbsd.cc:netbsd_gt_pch_use_address()
thus: if a compiled header cannot be mapped at its preferred
address, a region of memory is allocated and the base address of
this region is passed back to the caller
(ggc-common.cc:gt_pch_restore() I believe). Note that in this
case the return value is 0, allowing gt_pch_restore() to load the
header. In this respect the behaviour is slightly different from
that of the use_address hook for other hosts (e.g. Linux).
This change against GCC 15.2.0 builds on the work in pch/71934
(and target/58937)
ChangeLog:
* gcc/config/host-netbsd.cc (netbsd_gt_pch_use_address):
update for pch/71934
Generally it looks sensible. So my preference would be to fix both
NetBSD and OpenBSD at the same time, assuming we think both need
the same fix.
Ok. I will investigate a bit further and try to confirm that the
proposed change will also work for OpenBSD.
It'd be hugely appreciated. I'm an old BSD guy myself and would love
to see it better supported these days, but can't really spend any
time on it. In theory this ought to be testable in a VM.
I ended up netbooting OpenBSD/amd64 7.8 and compiling GCC 15.2.0 from
source. In addition to my patch, I also needed to apply the patches
from lang/gcc/15 in the OpenBSD ports repository (a converted version
of which is at https://github.com/openbsd/ports).
Having updated host-openbsd.cc with the same change as for NetBSD, I
tested the change by running cc1plus under lldb. Using lldb, the
first test in openbsd_gt_pch_use_address() (for addr == base) was
skipped, and the address returned by the second mmap() call was
modified to be 16kB above its original value. Once cc1plus had
finished, the assembly code it produced was inspected. The output
seemed reasonable and it contained values defined in the compiled
header, which is encouraging.
I've attached an updated version of the previous patch which updates
the use_address hook for NetBSD and for OpenBSD.
THanks. I pushed this to the trunk on your behalf.
jeff
