[LLVMdev] Any equivalent of --allow-multiple-definitions in llvm-ld?

[Talin]

Thanks Reid. The specific symbols in this case are static data structures,
not methods.


On Mon, Jul 14, 2014 at 3:17 PM, Reid Kleckner <rnk at google.com> wrote:

> Apparently lld accepts '-z muldefs' for this purpose.
>
> I'm curious if you can't solve this easily at the C++ language level,
> though.
>
> This explicit instantiation for example will be coalesced by the linker:
>
> template <typename T> struct A {
>   int foo() { return sizeof(T); }
> };
> template struct A<int>;
>
> This explicit specialization also defines inline functions which will be
> coalesced:
>
> template <typename T> struct A {
>   int foo() { return sizeof(T); }
> };
> template <> struct A<int> {
>   int foo() { return 4; }
> };
>
> Only this out of line method definition for a fully specialized class
> template generates strong symbols:
>
> template <typename T> struct A {
>   int foo() { return sizeof(T); }
> };
> template <> struct A<int> {
>   int foo();
> };
> int A<int>::foo() { return 4; }
>
> In which case, if I want them coalesced, I can probably just add the
> 'inline' keyword.
>
>
> On Mon, Jul 14, 2014 at 2:48 PM, Talin <viridia at gmail.com> wrote:
>
>> I'm working with a C++ code generator that produces multiple instances of
>> the same definition (specifically, it generates explicit instantiations of
>> the same template in multiple output source files). With the GNU ld, I'm
>> able to link successfully using the --allow-multiple-definitions flag;
>> however this flag is not supported in llvm-ld.
>>
>> Is there any way I can either convince llvm-ld to accept this without
>> producing an error, or alternatively is there any way in C++ that I can
>> trick the compiler into making these definitions linkonce?
>>
>> --
>> -- Talin
>>
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>>
>>
>


-- 
-- Talin
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