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Re: [Qemu-devel] [PULL 00/40] ppc patch queue 2015-06-03
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PULL 00/40] ppc patch queue 2015-06-03 |
Date: |
Fri, 05 Jun 2015 17:20:29 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 |
On 05/06/2015 17:08, Peter Maydell wrote:
>> > Can someone add a checkpatch rule that forbids shifting left U or UL
>> > constants (i.e. only ULL)? That would alleviate my concerns with these
>> > ubsan warnings.
>
> ...but things like "(1U << 31)" are entirely valid.
They're only valid until someone does a ~ on them. I think it's
reasonable to forbid them in our coding standards, if we want to fix
ubsan's warning of (1 << 31).
I don't think it's reasonable for compiler writers to exploit the
undefinedness of (1 << 31) anyway, and if it were possible to shut up
ubsan about this particular kind of undefined behavior, I would prefer it.
Paolo
- [Qemu-devel] [PULL 19/40] docs: add sPAPR hotplug/dynamic-reconfiguration documentation, (continued)
- [Qemu-devel] [PULL 19/40] docs: add sPAPR hotplug/dynamic-reconfiguration documentation, Alexander Graf, 2015/06/03
- [Qemu-devel] [PULL 26/40] spapr_events: re-use EPOW event infrastructure for hotplug events, Alexander Graf, 2015/06/03
- [Qemu-devel] [PULL 32/40] spapr_pci: enable basic hotplug operations, Alexander Graf, 2015/06/03
- [Qemu-devel] [PULL 20/40] spapr_drc: initial implementation of sPAPRDRConnector device, Alexander Graf, 2015/06/03
- Re: [Qemu-devel] [PULL 00/40] ppc patch queue 2015-06-03, Peter Maydell, 2015/06/04
- Re: [Qemu-devel] [PULL 00/40] ppc patch queue 2015-06-03, Peter Maydell, 2015/06/05
- Re: [Qemu-devel] [PULL 00/40] ppc patch queue 2015-06-03, Paolo Bonzini, 2015/06/05
- Re: [Qemu-devel] [PULL 00/40] ppc patch queue 2015-06-03, Peter Maydell, 2015/06/05
- Re: [Qemu-devel] [PULL 00/40] ppc patch queue 2015-06-03, Paolo Bonzini, 2015/06/05
- Re: [Qemu-devel] [PULL 00/40] ppc patch queue 2015-06-03, Peter Maydell, 2015/06/05
- Re: [Qemu-devel] [PULL 00/40] ppc patch queue 2015-06-03,
Paolo Bonzini <=
- Re: [Qemu-devel] [PULL 00/40] ppc patch queue 2015-06-03, Peter Maydell, 2015/06/05
- [Qemu-devel] undefined behavior of signed left shifts (was Re: [PULL 00/40] ppc patch queue 2015-06-03), Paolo Bonzini, 2015/06/05
- Re: [Qemu-devel] undefined behavior of signed left shifts (was Re: [PULL 00/40] ppc patch queue 2015-06-03), Peter Maydell, 2015/06/05
- Re: [Qemu-devel] undefined behavior of signed left shifts (was Re: [PULL 00/40] ppc patch queue 2015-06-03), Joseph Myers, 2015/06/05
Re: [Qemu-devel] [PULL 00/40] ppc patch queue 2015-06-03, Eric Blake, 2015/06/05