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From: Paolo Bonzini <pbonzini@redhat.com>
To: "Daniel P. Berrangé" <berrange@redhat.com>
Cc: qemu-devel@nongnu.org, vr_qemu@t-online.de, marcandre.lureau@redhat.com
Subject: Re: [PATCH] meson: remove -no-pie linker flag
Date: Tue, 23 May 2023 13:55:13 +0200	[thread overview]
Message-ID: <CABgObfbhdqfMzkOZVMGzUbdg4eL1AXc8b31LqKZ5QRTHksOsaA@mail.gmail.com> (raw)
In-Reply-To: <ZGx22AySUhoZZuW1@redhat.com>

On Tue, May 23, 2023 at 10:18 AM Daniel P. Berrangé <berrange@redhat.com> wrote:
> > The issue is that Meson only has "enable PIE" or "leave PIE to the
> > compiler default", while QEMU also has "disable PIE"---which is the
> > messy one.
>
> Does QEMU actually need "disable PIE" ? It existed in configure of
> course, is there a reason we need to continue to support it in meson ?

We have "disable PIE" support because PIE has a performance cost,
though that's mostly for 32-bit x86 processors. Other ISAs have
instructions that help (like x86-64's RIP-relative addressing,
aarch64's adr/adrp, or RISC-V's auipc) and then position-independent
code becomes the natural one anyway.

However, I am inclined to keep it also because "--disable-pie uses the
compiler default, and who knows what your distro did" is less obvious
than "--disable-pie disables PIE".

Paolo



  reply	other threads:[~2023-05-23 11:56 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-22  8:08 [PATCH] meson: remove -no-pie linker flag Paolo Bonzini
2023-05-22  8:19 ` Philippe Mathieu-Daudé
2023-05-22 14:39 ` Richard Henderson
2023-05-23  7:23   ` Paolo Bonzini
2023-05-22 15:54 ` Richard Henderson
2023-05-23  7:52   ` Michael Tokarev
2023-05-23  5:57 ` Volker Rümelin
2023-05-23  8:00 ` Daniel P. Berrangé
2023-05-23  8:02   ` Paolo Bonzini
2023-05-23  8:18     ` Daniel P. Berrangé
2023-05-23 11:55       ` Paolo Bonzini [this message]
2023-05-23 13:14       ` Richard Henderson

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