Re: [PATCH] ARM: Use different linker path for hardfloat ABI

[Richard Earnshaw <rearnsha at arm dot com>]

On 03/04/12 10:29, Andrew Haley wrote:
> On 04/02/2012 10:06 PM, dann frazier wrote:
>> On Fri, Mar 30, 2012 at 06:52:34PM +0100, Richard Earnshaw wrote:
>>> On 29/03/12 20:34, dann frazier wrote:
>>>> This is an updated version of a patch Debian and Ubuntu are using to
>>>> use an alternate linker path for hardfloat binaries. The difference
>>>> with this one is that it covers the case where no float flag
>>>> was passed in, defaulting to the softfloat path.
>>>>
>>>> 2012-03-29  dann frazier <dann.frazier@canonical.com>
>>>>
>>>> 	* config/arm/linux-elf.h: Use alternate linker path
>>>>           for hardfloat ABI
>>>>
>>>> Index: gcc/config/arm/linux-elf.h
>>>> ===================================================================
>>>> --- gcc/config/arm/linux-elf.h	(revision 185708)
>>>> +++ gcc/config/arm/linux-elf.h	(working copy)
>>>> @@ -59,14 +59,21 @@
>>>>  
>>>>  #define LIBGCC_SPEC "%{mfloat-abi=soft*:-lfloat} -lgcc"
>>>>  
>>>> -#define GLIBC_DYNAMIC_LINKER "/lib/ld-linux.so.2"
>>>> +#define LINUX_DYNAMIC_LINKER_SF "/lib/ld-linux.so.3"
>>>> +#define LINUX_DYNAMIC_LINKER_HF "/lib/arm-linux-gnueabihf/ld-linux.so.3"
>>>>  
>>>>  #define LINUX_TARGET_LINK_SPEC  "%{h*} \
>>>>     %{static:-Bstatic} \
>>>>     %{shared:-shared} \
>>>>     %{symbolic:-Bsymbolic} \
>>>>     %{rdynamic:-export-dynamic} \
>>>> -   -dynamic-linker " GNU_USER_DYNAMIC_LINKER " \
>>>> +   %{msoft-float:-dynamic-linker " LINUX_DYNAMIC_LINKER_SF "} \
>>>> +   %{mfloat-abi=soft*:-dynamic-linker " LINUX_DYNAMIC_LINKER_SF "} \
>>>> +   %{mhard-float:-dynamic-linker " LINUX_DYNAMIC_LINKER_HF "} \
>>>> +   %{mfloat-abi=hard:-dynamic-linker " LINUX_DYNAMIC_LINKER_HF "} \
>>>> +   %{!mfloat-abi: \
>>>> +     %{!msoft-float: \
>>>> +       %{!mhard-float:-dynamic-linker " LINUX_DYNAMIC_LINKER_SF "}}} \
>>>>     -X \
>>>>     %{mbig-endian:-EB} %{mlittle-endian:-EL}" \
>>>>     SUBTARGET_EXTRA_LINK_SPEC
>>>>
>>>
>>> Looks to me as though this will break the old Linux ABI.  While we've
>>> marked that as deprecated, it hasn't been removed as yet.  So I think
>>> this patch either needs to wait until that removal has taken place, or
>>> provide the relevant updates to maintain the old ABI support.
>>
>> Thanks for your review. You're right, this does appear to break the
>> old ABI - that was a misunderstanding on my part. I think this fixes
>> the problem:
> 
> But what about those of us who are using hard-float but not the
> Debian liker path?  It'll break, surely.  This looks to be like
> it's Debian-specific.
> 

Are you trying to tell me that some distros are using /lib/ld-linux.so.3
directly for hard-float?  Sigh, you distro guys need to start talking to
each other, rather than just going of inventing things ...

If, so then there's only one way to sort out this mess.

/lib/arm-linux-gnueabi/ld-linux.so.3  Location of soft-float loader
/lib/arm-linux-gnueabihf/ld-linux.so.3 Location of hard-float loader
/lib/ld-linux.so.3 legacy symlink to one of the above.

Or something of this nature.

All this is outside of GCC's remit though and I'm not in a position to
drive any of it through.

:-( :-( :-(

R.