Following legacy packing conventions, `isArm` was defined just for
32-bit ARM instruction set. This is confusing to non packagers though,
because Aarch64 is an ARM instruction set.
The official ARM overview for ARMv8[1] is surprisingly not confusing,
given the overall state of affairs for ARM naming conventions, and
offers us a solution. It divides the nomenclature into three levels:
```
ISA: ARMv8 {-A, -R, -M}
/ \
Mode: Aarch32 Aarch64
| / \
Encoding: A64 A32 T32
```
At the top is the overall v8 instruction set archicture. Second are the
two modes, defined by bitwidth but differing in other semantics too, and
buttom are the encodings, (hopefully?) isomorphic if they encode the
same mode.
The 32 bit encodings are mostly backwards compatible with previous
non-Thumb and Thumb encodings, and if so we can pun the mode names to
instead mean "sets of compatable or isomorphic encodings", and then
voilà we have nice names for 32-bit and 64-bit arm instruction sets
which do not use the word ARM so as to not confused either laymen or
experienced ARM packages.
[1]: https://developer.arm.com/products/architecture/a-profile
Source master rebase of my [PR #34].
Eventually, we might consider doing something for GNU binutils too, in
order that we switch (the normal) ld-wrapper to always use this to
leverage ld to resolve libraries, rather than faking it in bash.
[PR #34]: https://github.com/tpoechtrager/cctools-port/pull/34
Since at least d7bddc27b2, we've had a
situation where one should depend on:
- `stdenv.cc.bintools`: for executables at build time
- `libbfd` or `libiberty`: for those libraries
- `targetPackages.cc.bintools`: for exectuables at *run* time
- `binutils`: only for specifically GNU Binutils's executables,
regardless of the host platform, at run time.
and that commit cleaned up this usage to reflect that. This PR flips the
switch so that:
- `binutils` is indeed unconditionally GNU Binutils
- `binutils-raw`, which previously served that role, is gone.
so that the correct usage will be enforced going forward and everything
is simple.
N.B. In a few cases `binutils-unwrapped` (which before and now was
unconditionally actual GNU binutils), rather than `binutils` was used to
replace old `binutils-raw` as it is friendly towards some cross
compilation usage by avoiding a reference to the next bootstrapping
change.
