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Re: RFC: Add ___tls_get_addr


On 05/07/17 16:38, H.J. Lu wrote:
> On x86-64, __tls_get_addr has to realigns stack so that binaries compiled by
> GCCs older than GCC 4.9.4:
> 
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58066
> 
> continue to work even if vector instructions are used by functions called
> from __tls_get_addr, which assumes 16-byte stack alignment as specified
> by x86-64 psABI.
> 
> We are considering to add an alternative interface, ___tls_get_addr, to
> glibc, which doesn't realign stack.  Compilers, which properly align stack
> for TLS, call generate call to ___tls_get_addr, instead of __tls_get_addr,
> if ___tls_get_addr is available.
> 
> Any comments?
> 
> 

what happens when new compiler generating the new symbol
is used with old glibc?



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