MCValue: Store SymA specifier at Specifier
The relocation specifier should be accessed via MCValue::Specifier.
However, some targets encode the relocation specifier within SymA using
MCSymbolRefExpr::SubclassData and access it via getAccessVariant(), though
this method is now deprecated.
This change stores the SymA specifier at Specifier as well, unifying the
two code paths.
* CSKY: GOT- and PLT- relocations now suppress the STT_SECTION
conversion.
* AArch64: https://reviews.llvm.org/D156505 added `getRefkind` check to
prevent folding. This is a hack and is now removed.
MCValue: Unify relocation specifier storage by storing SymA specifier at Specifier
The relocation specifier is accessed via MCValue::Specifier, but some
targets encoded it within SymA using MCSymbolRefExpr::SubclassData and
retrieved it through the now-deprecated getAccessVariant() method. This
commit unifies the two approaches by storing the SymA specifier at
`Specifier` as well.
Additional changes:
- CSKY: GOT- and PLT- relocations now suppress STT_SECTION conversion.
- AArch64: Removed the `getRefkind` check hack (introduced in https://reviews.llvm.org/D156505) that prevented folding.
Removed the assertion from `getRelocType`.
- RISCV: Removed the assertion from `getRelocType`.
Future plans:
- Replace MCSymbolRefExpr members with MCSymbol within MCValue.
- Remove `getSymSpecifier` (added for migration).
