[llvmlinux] "make test" for x86_64 target just hung there, why?

[Daniel Sanders]

It could be that GCC does more inlining and optimises the bug away. This happened to me with the slab allocator initialization on the Mips arch.

At the time, I was able to reproduce it in GCC by making the inline and always_inline macros empty. I don't recall the exact spelling of those macros, they may have additional underscores.

Hope that helps.
________________________________________
From: llvmlinux-bounces at lists.linuxfoundation.org [llvmlinux-bounces at lists.linuxfoundation.org] on behalf of Sedat Dilek [sedat.dilek at gmail.com]
Sent: 11 September 2015 17:10
To: pageexec at gmail.com
Cc: llvmlinux at lists.linuxfoundation.org; David Woodhouse
Subject: Re: [llvmlinux] "make test" for x86_64 target just hung there, why?

On Wed, Sep 9, 2015 at 10:24 PM, PaX Team <pageexec at gmail.com> wrote:
> On 9 Sep 2015 at 12:12, Sedat Dilek wrote:
>
>> I can boot into a CLANG v3.7 compiled kernel when lib/bitmap is
>> compiled with GCC v4.9.
>
> are you sure it's not lib/hweight.o instead? under gcc it's compiled
> with special flags (CONFIG_ARCH_HWEIGHT_CFLAGS) which clang doesn't
> support and we used to patch that out but i have no idea about the
> current state of affairs.
>

Hi pipacs :-),

if I switch the compiler with the same llvmlinux-patchset and
kernel-config GCC v4.9 builds fine.
So, I am not sure if the CLANG v3.7 compiler is BROKEN when doing
(always-)inlining functions.

Can you give some aid, how to verify if it is a COMPILER problem or a
kernel-side one?

Regards,
- Sedat -
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