Re: [PATCH 3/3] CHANGELOG: Minimum toolchain requirements

[Oleksii Kurochko <oleksii.kurochko@gmail.com>]

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On 3/27/25 4:45 PM, Andrew Cooper wrote:
> On 21/03/2025 4:24 pm, Oleksii Kurochko wrote:
>>
>> On 3/20/25 4:59 PM, Andrew Cooper wrote:
>>> Signed-off-by: Andrew Cooper<andrew.cooper3@citrix.com>
>>> ---
>>> CC: Anthony PERARD<anthony.perard@vates.tech>
>>> CC: Michal Orzel<michal.orzel@amd.com>
>>> CC: Jan Beulich<jbeulich@suse.com>
>>> CC: Julien Grall<julien@xen.org>
>>> CC: Roger Pau Monné<roger.pau@citrix.com>
>>> CC: Stefano Stabellini<sstabellini@kernel.org>
>>> CC: Oleksii Kurochko<oleksii.kurochko@gmail.com>
>>> ---
>>>   CHANGELOG.md | 3 +++
>>>   1 file changed, 3 insertions(+)
>>>
>>> diff --git a/CHANGELOG.md b/CHANGELOG.md
>>> index 9a5919585d43..4e333e608a96 100644
>>> --- a/CHANGELOG.md
>>> +++ b/CHANGELOG.md
>>> @@ -7,6 +7,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
>>>   ## [4.21.0 UNRELEASED](https://xenbits.xenproject.org/gitweb/?p=xen.git;a=shortlog;h=staging) - TBD
>>>   
>>>   ### Changed
>>> + - The minimum toolchain requirements have been increased to either:
>>> +   - GCC 5.1 and Binutils 2.25, or
>>> +   - Clang/LLVM 11
>> I think we want here to specify for which architectures it was done as RISC-V, for example, uses
>> different versions:
>>   - GCC 12.2 or later
>>   - GNU Binutils 2.39 or later
>> And for clang the version will be 17 as:
>>    f873029386dd415cd9caa78f600a593d9570c9ae("[BOLT] Add minimal RISC-V 64-bit support")
>>    $ git tag --contains f873029386dd415cd9caa78f600a593d9570c9ae
>>      llvmorg-17.0.0
>>    ...
>> I have some patch to build Xen RISC-V using clang-17 but I haven't sent to upstream yet as I am not
>> really sure that if we need (or why we need) clang support just from the start.
> The same reason why we got an almost-nothing build in CI first, and are
> currently looking for a "hello world" message on boot.
>
> Keeping it working as you go is much easier than retrofitting at a later
> point, and supporting more than 1 of any $THING (not just compilers) is
> good to prevent accidental reliance on an implementation specific property.
>
> The only question is what version of Clang exists in Debian bookworm, as
> that affects how easy/hard it is to add to CI.
>
> According tohttps://packages.debian.org/search?keywords=clang, bookworm
> has Clang 14, while trixie has Clang 19.
>
> So, how hard a limit is Clang-17?  Is Clang-14 doable or not?

I think it is pretty hard limit because:
1. I haven't checked all the extension but, for example, we required 'H' extension and
    the support for it was added in 16.0.0:
    [f4c887c3a8406d85f4f942c8350f10026994f4d8("RISCV] Add H extension")
    $ git tag --contains f4c887c3a8406d85f4f942c8350f10026994f4d8
      llvmorg-16.0.0
      ...
2. Minimal support for RISCV-64 was added in clang17:
    f873029386dd415cd9caa78f600a593d9570c9ae("[BOLT] Add minimal RISC-V 64-bit support")
    $ git tag --contains f873029386dd415cd9caa78f600a593d9570c9ae
      llvmorg-17.0.0
      ...
And, actually, the second one reason was the reason why I tried to build with clang17 and suggests to use
it as a baseline.

>
> Alternatively, we could start adding some trixie containers.  We have
> passed the toolchain freeze (was 15th March), so the build container
> should be stable now, even if it isn't quite released yet.

clang has nice script to add any version. I did that in the following way
for bookworm docker container:
+    DEPS=(
+        # Clang
+        wget
+        gnupg
+        ca-certificates
+        lsb-release
+        software-properties-common
...

+    update-ca-certificates
+
+    wget -O -https://apt.llvm.org/llvm.sh | bash -s 17
+    wget -O -https://apt.llvm.org/llvm.sh | bash -s 18
+    wget -O -https://apt.llvm.org/llvm.sh | bash -s 19
+    wget -O -https://apt.llvm.org/llvm.sh | bash -s 20
+    # ln -s /usr/bin/clang-17 /usr/bin/clang

~ Oleksii

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