…e data

…nd make ImmTy::imm field private

The differences if they are discovered will need to be explicitly documented

as much as possible.

The old naming is from ancient times when there was no MSVC support.

Also `uefi_base` -> `uefi_msvc_base`.
It will inherit from `msvc_base` in a future commit, plus a GNU UEFI target is also potentially possible.

and inherit both `windows_msvc_base` and `uefi_msvc_base` from it.

…able

Some helpers functions have been introduced to deal with (buggy) cases
where either a `NodeId` or a `DefId` do not have a corresponding `HirId`.
Those cases are tracked in issue rust-lang#71104.

unit rvalue, use constant `()` instead of tuple

fixes rust-lang#70886

r? @eddyb

rustc_target: Refactor target specifications related to Windows and UEFI

- LLD support is improved.
- Code is cleaned up.
- Target specs are organized in a more hierarchical way.
- Possible issues in UWP and UEFI platforms are identified (see FIXMEs).

The code is better read per-commit.

Miri: expand frame hooks

This is needed to make rust-lang/miri#1330 work.

r? @oli-obk @eddyb

…=eddyb

Entirely remove `DUMMY_HIR_ID`

Some helpers functions have been introduced to deal with (buggy) cases
where either a `NodeId` or a `DefId` do not have a corresponding `HirId`.
Those cases are tracked in issue rust-lang#71104.