https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104288
Christian Prochaska <christian.procha...@genode-labs.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |christian.prochaska@genode-
| |labs.com
--- Comment #13 from Christian Prochaska <christian.procha...@genode-labs.com>
---
I found the "Register non-null side effects properly." commit with git bisect
while debugging a page fault in the Genode OS framework built with GCC 12.2.0.
It turned out that a null pointer check which was present before this commit is
now not present anymore. The C++ code with the null pointer check can be found
on GitHub:
https://github.com/genodelabs/genode/blob/a84af9a9606450471b8038a35f9b55057efa0850/repos/base-nova/src/lib/base/ipc.cc#L71
This is the implementation of the 'Thread::myself()' function which returns a
null pointer in some conditions:
https://github.com/genodelabs/genode/blob/a84af9a9606450471b8038a35f9b55057efa0850/repos/base/src/lib/base/thread_myself.cc#L22
I compared the disassembled code from objdump and this part is missing when the
commit is applied:
Genode::ipc_call(Genode::Native_capability, Genode::Msgbuf_base&,
Genode::Msgbuf_base&, unsigned long):
/.../repos/base-nova/src/lib/base/ipc.cc:71
addr_t const manual_rcv_sel = myself ?
myself->native_thread().client_rcv_sel
85f78: 48 83 bd 50 ff ff ff cmpq $0x0,-0xb0(%rbp)
85f7f: 00
85f80: 48 c7 c3 ff ff ff ff mov $0xffffffffffffffff,%rbx
85f87: 74 1d je 85fa6
<Genode::ipc_call(Genode::Native_capability, Genode::Msgbuf_base&,
Genode::Msgbuf_base&, unsigned long)
/.../repos/base-nova/src/lib/base/ipc.cc:71 (discriminator 1)
Now I'm not sure if the problem is in the Genode code or in GCC. Any ideas?
