Re: [edk2-devel] [RFC] Move CompilerIntrinsicsLib and ArmSoftFloatLib to MdePkg

["Ard Biesheuvel" <ardb@kernel.org>]

On Fri, 2 Aug 2024 at 00:39, Oliver Smith-Denny
<osde@linux.microsoft.com> wrote:
>
> CompilerIntrinsicsLib and ArmSoftFloatLib add ARM/AARCH64 compiler
> intrinsics and floating point functions required by OpenSSL,
> respectively. CompilerIntrinsicsLib is used almost in every DSC that
> builds ARM/AARCH64 and ArmSoftFloatLib is used by every DSC that builds
> logic from OpenSSL.

What's even worse: OpenSSL doesn't really use floating point at all -
the only reason we need this is because there is some global double_t
somewhere that records entropy or somesuch, but IIRC that code is not
actually used.

So perhaps we could add a hack in OpensslLib to work around this in
one way or another for ARM only, and get rid of SoftFloatLib
altogether.

> Together these make almost every DSC have a
> dependency on ArmPkg, which is odd and for a handful, MdeModulePkg,
> EmbeddedPkg, and ShellPkg, namely, it is a circular dependency.
>
> There have been previous mailing list suggestions to move
> CompilerIntrinsicsLib to MdePkg (possibly combining with other arch
> intrinsics). I am not sure the end status of those conversations. By
> moving these two libraries to MdePkg package, we accomplish a few
> things:
>
>    - Removing the circular dependency from MdeModulePkg and ShellPkg
>      (EmbeddedPkg has other ArmPkg dependencies)
>
>    - Aligning MdePkg as the base package where baseline build and spec
>      dependencies are found with other industry standard behavior
>
>    - Detangling ArmPkg and making ARM/AARCH64 more of a first class
>      citizen in edk2 instead of bolted onto the side
>
> There is no functional change here and the amount of work is light, but
> I think it moves edk2 in the direction it wants to go, so I'm happy to
> put up a PR for this, but I wanted to get feedback before I did so. This
> aligns with similar efforts, such as moving more ARM/AARCH64 chipset
> definitions to MdePkg from ArmPkg [1][2][3]. This also aligns to the
> overall goal of deleting ArmPkg:
> https://bugzilla.tianocore.org/show_bug.cgi?id=4121
>

Intrinsics are tightly coupled with the toolchain, and so it would
make sense for the basetools to provide them. Intrinsics are also
-essentially- build once, run everywhere objects so I don't think we
need the typical handling for them either, and we could just build
them once when we build the basetools.


-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#120210): https://edk2.groups.io/g/devel/message/120210
Mute This Topic: https://groups.io/mt/107675828/7686176
Group Owner: devel+owner@edk2.groups.io
Unsubscribe: https://edk2.groups.io/g/devel/unsub [rebecca@openfw.io]
-=-=-=-=-=-=-=-=-=-=-=-