From: "Daniel P. Berrangé" <berrange@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Alexander Bulekov <alxndr@bu.edu>, Thomas Huth <thuth@redhat.com>,
qemu-devel@nongnu.org, Daniele Buono <dbuono@linux.vnet.ibm.com>
Subject: Re: [PATCH v2 3/6] configure: add option to enable LTO
Date: Mon, 26 Oct 2020 15:50:06 +0000 [thread overview]
Message-ID: <20201026155006.GE496050@redhat.com> (raw)
In-Reply-To: <7aa00aba-ff8c-252a-899a-45ef4db7cc6e@redhat.com>
On Mon, Oct 26, 2020 at 10:51:43AM +0100, Paolo Bonzini wrote:
> On 23/10/20 22:06, Daniele Buono wrote:
> > This patch allows to compile QEMU with link-time optimization (LTO).
> > Compilation with LTO is handled directly by meson. This patch adds checks
> > in configure to make sure the toolchain supports LTO.
> >
> > Currently, allow LTO only with clang, since I have found a couple of issues
> > with gcc-based LTO.
> >
> > In case fuzzing is enabled, automatically switch to llvm's linker (lld).
> > The standard bfd linker has a bug where function wrapping (used by the fuzz*
> > targets) is used in conjunction with LTO.
> >
> > Tested with all major versions of clang from 6 to 12
> >
> > Signed-off-by: Daniele Buono <dbuono@linux.vnet.ibm.com>
>
> What are the problems like if you have GCC or you ar/linker are not up
> to the job? I wouldn't mind omitting the tests since this has to be
> enabled explicitly by the user.
We temporarily disabled LTO in Fedora rawhide due to GCC bugs causing
wierd test suite asserts. Those were pre-release versions of GCC/binutils
though. I've just tested again and LTO works correctly, so I've enabled
LTO once again.
Regards,
Daniel
--
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next prev parent reply other threads:[~2020-10-26 15:54 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-23 20:06 [PATCH v2 0/6] Add support for Control-Flow Integrity Daniele Buono
2020-10-23 20:06 ` [PATCH v2 1/6] fuzz: Make fork_fuzz.ld compatible with LLVM's LLD Daniele Buono
2020-10-23 20:06 ` [PATCH v2 2/6] configure: avoid new clang 11+ warnings Daniele Buono
2020-10-24 5:17 ` Thomas Huth
2020-10-24 12:42 ` Daniele Buono
2020-10-26 9:50 ` Paolo Bonzini
2020-10-26 15:03 ` Daniele Buono
2020-10-26 15:12 ` Paolo Bonzini
2020-10-26 21:40 ` Daniele Buono
2020-10-26 22:08 ` Peter Maydell
2020-10-27 11:26 ` Thomas Huth
2020-10-27 11:38 ` Cornelia Huck
2020-10-27 16:17 ` Daniele Buono
2020-10-23 20:06 ` [PATCH v2 3/6] configure: add option to enable LTO Daniele Buono
2020-10-26 9:51 ` Paolo Bonzini
2020-10-26 15:50 ` Daniel P. Berrangé [this message]
2020-10-27 14:57 ` Daniele Buono
2020-10-27 15:17 ` Daniel P. Berrangé
2020-10-27 20:42 ` Daniele Buono
2020-10-28 6:44 ` Paolo Bonzini
2020-10-28 18:22 ` Daniele Buono
2020-10-29 10:19 ` Paolo Bonzini
2020-10-28 9:35 ` Alex Bennée
2020-10-28 18:47 ` Daniele Buono
2020-10-23 20:06 ` [PATCH v2 4/6] cfi: Initial support for cfi-icall in QEMU Daniele Buono
2020-10-26 9:52 ` Paolo Bonzini
2020-10-27 10:11 ` Alex Bennée
2020-10-23 20:06 ` [PATCH v2 5/6] check-block: enable iotests with cfi-icall Daniele Buono
2020-10-23 20:06 ` [PATCH v2 6/6] configure: add support for Control-Flow Integrity Daniele Buono
2020-10-26 10:00 ` Paolo Bonzini
2020-10-23 20:33 ` [PATCH v2 0/6] Add " Eric Blake
2020-10-24 11:58 ` Daniele Buono
2020-10-26 9:26 ` Daniel P. Berrangé
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