[OE-core] [PATCH v2 4/5] bitbake.conf: include ASNEEDED in TARGET_LDFLAGS directly

[Khem Raj]

On Wed, May 30, 2018 at 10:46 AM, Andre McCurdy <armccurdy at gmail.com> wrote:
> On Tue, May 29, 2018 at 7:13 PM, Khem Raj <raj.khem at gmail.com> wrote:
>> On Tue, May 29, 2018 at 2:29 PM, Andre McCurdy <armccurdy at gmail.com> wrote:
>>> Previously, ASNEEDED was appended to TARGET_LDFLAGS from
>>> as-needed.inc via tcmode-default.inc and so may not have been enabled
>>> for external toolchain builds or other configurations which over-ride
>>> TCMODE (ie builds which do not include tcmode-default.inc).
>>>
>>> Include ASNEEDED in TARGET_LDFLAGS directly from bitbake.conf to
>>> ensure that the optimisation is applied to all builds (and for
>>> consistency with the way that TARGET_LINK_HASH_STYLE is handled).
>>
>> We have to be ensure that external toolchains can either override or support
>> --as-needed feature,
>
> External toolchains can easily over-ride ASNEEDED if they need to.
>
>> since we may not be able to control what linker they use
>> or version of gnu ld they may deploy.
>
> When was --as-needed first added to gnu ld? Do you know of an external
> toolchain which might not support it?
>

If they have new enough binutils it should not be an issue. but I dont know
if there are such SDKs out there, thats where external toolchain makers can
help. Otherwise we can assume its fine.

>> From internal toolchains pov
>> this is a good change, but It would be good if some users of external toolchains
>> can chime in.