RFA (libstdc++): PATCH to implement C++17 over-aligned new

[Jonathan Wakely]

On 11/09/16 09:08 +0200, Christophe Lyon wrote:
>On 10 September 2016 at 08:59, Christophe Lyon
><christophe.lyon@linaro.org> wrote:
>> On 9 September 2016 at 23:20, Jason Merrill <jason@redhat.com> wrote:
>>> On Thu, Sep 8, 2016 at 7:06 AM, Jonathan Wakely <jwakely@redhat.com> wrote:
>>>> On 08/09/16 09:10 +0200, Marc Glisse wrote:
>>>>>
>>>>> Do we want a generic fallback implementation (similar to
>>>>> gcc/config/i386/gmm_malloc.h)? A windows version with _aligned_malloc /
>>>>> _aligned_free would also be possible.
>>>>
>>>> Making it work for MinGW would be nice.
>>>
>>> OK, this is what I'm checking in; could someone test it on MinGW?
>>>
>>> Jason
>>
>> Hi Jason,
>>
>> I'm seeing problems on arm*linux: the tests aligned-new[1235].C fail to link:
>> aligned-new5.C:(.text+0x14): undefined reference to `operator
>> new(unsigned int, std::align_val_t)'
>>
>>
>> On aarch64*-elf and arm-eabi (using newlib), I'm seeing:
>> /gccsrc/libstdc++-v3/libsupc++/new_opa.cc:66: undefined reference to
>> `aligned_alloc'
>>
>> Am I missing something in my setup?
>>
>
>I'm seeing an additional problem: to GCC build is broken after this
>commit for target arm-none-eabi (using default cpu):
>/home/christophe.lyon/src/GCC/sources/gcc-fsf/reg-240062/libstdc++-v3/libsupc++/new_opant.cc:
>In function 'void* operator new(std::size_t, std::align_val_t, const
>std::nothrow_t&)':
>/home/christophe.lyon/src/GCC/sources/gcc-fsf/reg-240062/libstdc++-v3/libsupc++/new_opant.cc:33:3:
>error: '__try' was not declared in this scope
>   __try
>   ^~~~~
>/home/christophe.lyon/src/GCC/sources/gcc-fsf/reg-240062/libstdc++-v3/libsupc++/new_opant.cc:37:11:
>error: expected primary-expression before '...' token
>   __catch(...)
>           ^~~
>/home/christophe.lyon/src/GCC/sources/gcc-fsf/reg-240062/libstdc++-v3/libsupc++/new_opant.cc:37:3:
>error: '__catch' was not declared in this scope
>   __catch(...)
>   ^~~~~~~
>/home/christophe.lyon/src/GCC/sources/gcc-fsf/reg-240062/libstdc++-v3/libsupc++/new_opant.cc:41:1:
>warning: no return statement in function returning non-void
>[-Wreturn-type]
> }
> ^
>/home/christophe.lyon/src/GCC/sources/gcc-fsf/reg-240062/libstdc++-v3/libsupc++/new_opant.cc:30:26:
>warning: unused parameter 'sz' [-Wunused-parameter]
> operator new(std::size_t sz, std::align_val_t al, const std::nothrow_t&)
>                          ^~
>/home/christophe.lyon/src/GCC/sources/gcc-fsf/reg-240062/libstdc++-v3/libsupc++/new_opant.cc:30:47:
>warning: unused parameter 'al' [-Wunused-parameter]
> operator new(std::size_t sz, std::align_val_t al, const std::nothrow_t&)
>                                               ^~
>make[4]: *** [new_opant.lo] Error 1
>make[4]: Leaving directory
>`/home/christophe.lyon/src/GCC/builds/gcc-fsf-reg-240062/obj-arm-none-eabi/gcc3/arm-none-eabi/libstdc++-v3/libsupc++'

Hmm, I'm not sure why it's not failing on all targets, but this should
fix it. Could you test it?

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