[llvm-dev] lld: order of object files to be put into executable

[James Henderson via llvm-dev]

Hi Quolick,

I don't know if you are using the ELF or COFF LLD (I do not know the
latter), but at least if you are using the ELF linker, you could use the
--symbol-ordering-file option to put symbols from the object files you care
about next to each other. This orders the input sections from the object
file, based on the requested symbol order. This could be used to achieve
the code locality as suggested by Nicolai.

Regards,

James

On 26 February 2018 at 06:48, Nicolai Hähnle via llvm-dev <
llvm-dev at lists.llvm.org> wrote:

> Hi Quolick,
>
> the order of pages in an executable doesn't really matter in modern
> operating systems. The relevant parts of the executable are mmap()ed and
> loaded on demand.
>
> Although, keeping related code together for locality could be an advantage
> (both at load times w/ readahead and in the TLB during runtime), so that's
> a more interesting question to pursue.
>
> Cheers,
> Nicolai
>
>
> On 26.02.2018 05:33, Quolick via llvm-dev wrote:
>
>> Hi all!
>>
>> Is it possible somehow to specify *order* of object files to be put to
>> executable file?
>> For example, I want to put obj1.o and obj2.o somewhere at the beginning,
>> so when executable file would be mapped
>> to memory, this code would be accessed quickly.
>>
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>> llvm-dev at lists.llvm.org
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>>
>>
>
> --
> Lerne, wie die Welt wirklich ist,
> Aber vergiss niemals, wie sie sein sollte.
>
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