[LLD] Implement NOCROSREFS support for overlays in linker script handling of LLD

[Prabhuk]

Consider the following incomplete linker script snippet:

OVERLAY <START_ADDRESS>: NOCROSSREFS {
    .overlay.ob1 {*ob1*.o (.text*)}
    .overlay.ob2 {*ob2*.o (.text*)}
 } >SOME_MEMORY

LLD fails with { expected, but got NOCROSSREFS while processing this.

Ideally, we would like to match the BFD linker behavior for NOCROSSREFS in this case.

[llvmbot]

@llvm/issue-subscribers-lld-elf

Author: Prabhuk (OOO till April 2nd Week) (Prabhuk)

Consider the following incomplete linker script snippet:

OVERLAY <START_ADDRESS>: NOCROSSREFS {
    .overlay.ob1 {*ob1*.o (.text*)}
    .overlay.ob2 {*ob2*.o (.text*)}
 } >SOME_MEMORY

LLD fails with { expected, but got NOCROSSREFS while processing this.

Ideally, we would like to match the BFD linker behavior for NOCROSSREFS in this case.