[AArch64][ELF] Prefer to lower MC_GlobalAddress operands to .Lfoo$local

Authored by MaskRay on May 7 2021, 9:44 AM.


[AArch64][ELF] Prefer to lower MC_GlobalAddress operands to .Lfoo$local

Similar to X86 D73230 & 46788a21f9152be3950e57dc526454655682bdd4

With this change, we can set dso_local in clang's -fpic -fno-semantic-interposition mode,
for default visibility external linkage non-ifunc-non-COMDAT definitions.

For such dso_local definitions, variable access/taking the address of a
function/calling a function will go through a local alias to avoid GOT/PLT.

Note: the 'S' inline assembly constraint refers to an absolute symbolic address
or a label reference (D46745).

Differential Revision: https://reviews.llvm.org/D101872