[Buildroot] [PATCH 1/2] bfin: remove the dependency of flat shared mode to shared library

Arnout Vandecappelle arnout at mind.be
Tue Mar 24 19:09:09 UTC 2015


On 23/03/15 03:43, Sonic Zhang wrote:
> Hi Thomas,
> 
> On Sat, Mar 21, 2015 at 5:45 AM, Thomas Petazzoni
> <thomas.petazzoni at free-electrons.com> wrote:
>> Dear Sonic Zhang,
>>
>> On Wed, 18 Mar 2015 16:59:15 +0800, Sonic Zhang wrote:
>>> From: Sonic Zhang <sonic.zhang at analog.com>
>>>
>>> Blackfin flat shared library isn't generated and linked in the same way
>>> as the ELF shared library. So, don't mark it depend on the static library
>>> only.
>>>
>>> Signed-off-by: Sonic Zhang <sonic.zhang at analog.com>
>>> ---
>>>  arch/Config.in |    1 -
>>>  1 file changed, 1 deletion(-)
>>>
>>> diff --git a/arch/Config.in b/arch/Config.in
>>> index 16ad8be..6179960 100644
>>> --- a/arch/Config.in
>>> +++ b/arch/Config.in
>>> @@ -295,7 +295,6 @@ config BR2_BINFMT_FLAT_SEP_DATA
>>>
>>>  config BR2_BINFMT_FLAT_SHARED
>>>       bool "Shared binary"
>>> -     select BR2_BINFMT_SUPPORTS_SHARED
>>
>> If you don't select BR2_BINFMT_SUPPORTS_SHARED, then the only available
>> option amongst: static libs, static libs + shared libs, shared libs is
>> "static libs", which means that the "-static" flag is always passed. If
>> that's OK, then I'm fine with the patch.
>>
> Yes, -static is OK in the link flag for FLAT shared mode.

 But then it won't generate dynamically linked executables, right?


>> The second sentence of your commit log is confusing however. You say
>> "don't mark it depend on the static library only". But it is exactly
>> what your patch is doing: since it's no longer select
>> BR2_BINFMT_SUPPORTS_SHARED, it means that after your patch is applied,
>> when BR2_BINFMT_FLAT_SHARED is used, the *only* possibility is static
>> library only.
> 
> Sorry for the typo error. Should be "mark it depend on the static
> library only"".

 The problem is the following: when we say 'depends on !STATIC', that typically
means that the package is using dlopen, which is not possible with FLAT. So it
would be wrong to say that FLAT selects BR2_STATIC_LIBS.

 The right solution would be to introduce something else for dlopen, and rename
all the BR2_STATIC_LIBS dependencies to that new symbol.


 Regards,
 Arnout


-- 
Arnout Vandecappelle                          arnout at mind be
Senior Embedded Software Architect            +32-16-286500
Essensium/Mind                                http://www.mind.be
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