[PATCH] D13615: [lld][elf2] Local Dynamic TLS

[Rafael Espíndola via llvm-commits]

We had a chat "offline".

I asked Michael to split this in 3 patches for easier discussion:

* Ordering the TLS sections.
* Creating the TLS segment.
* Handling the relocations.

For the first part, there a few properties of tls to keep in mind
* There is only one segment, so the NOBITS part of TLS has to be just
after the non NOBITS part.
* All actual TLS sections are RW, so we only need to put the tls logic
once we know we are in a single PT_LOAD.
* If it is NOBITS TLS, it must come before non TLS. If it is a non
NOBITS TLS, it must come after.

Cheers,
Rafael