I think this is working correctly. Without also removing sse2 from the
feature set, sse gets added back into the set because sse2 is part of
the x86_64 baseline (which is the cpu provided) and sse2 depends on sse.
in favor of CPU features. Also rearrange the `std.Target`
data structure.
* note: `@import("builtin")` was already deprecated in favor of
`@import("std").builtin`.
* `std.builtin.arch` is now deprecated in favor of
`std.builtin.cpu.arch`.
* `std.Target.CpuFeatures.Cpu` is now `std.Target.Cpu.Model`.
* `std.Target.CpuFeatures` is now `std.Target.Cpu`.
* `std.Target` no longer has an `arch` field. Instead it has a
`cpu` field, which has `arch`, `model`, and `features`.
* `std.Target` no longer has a `cpu_features` field.
* `std.Target.Arch` is moved to `std.Target.Cpu.Arch` and
it is an enum instead of a tagged union.
* `std.Target.parseOs` is moved to `std.Target.Os.parse`.
* `std.Target.parseAbi` is moved to `std.Target.Abi.parse`.
* `std.Target.parseArchSub` is only for arch now and moved
to `std.Target.Cpu.Arch.parse`.
* `std.Target.parse` is improved to accept CPU name and features.
* `std.Target.Arch.getBaselineCpuFeatures` is moved to
`std.Target.Cpu.baseline`.
* `std.Target.allCpus` is renamed to `std.Target.allCpuModels`.
* `std.Target.defaultAbi` is moved to `std.Target.Abi.default`.
* Significant cleanup of aarch64 and arm CPU features, resulting in
the needed bit count for cpu feature set going from 174 to 138.
* Add `std.Target.Cpu.Feature.Set.addFeatureSet` for merging
feature sets together.
`-target-feature` and `-target-cpu` are removed in favor of
`-mcpu`, to conform to established conventions, and it gains
additional power to support cpu features. The syntax is:
-mcpu=name+on1+on2-off1-off2
closes#4261
* remove "cpu features" that are actually just processors
* rename `v8` to `v8a`. this matches the corresponding
change to target/aarch64.zig
* rename types in preparation for removing sub-architecture
from `std.Target`.
I have other files changed in my dirty working tree, but about to make
some changes to arm.zig that I don't want batched with this commit.
The current target's ABI cannot be relied on for this.
For example, we may build the zig compiler for target
riscv64-linux-musl and provide a tarball for users to
download. A user could then run that zig compiler on
riscv64-linux-gnu. This use case is well-defined and
supported by Zig. But that means that we must detect
the system ABI here rather than
relying on `std.Target.current`.
Some C compilers, such as Clang, are known to rely on
argv[0] to find the path to their own executable,
without even bothering to resolve PATH. This results
in the message:
error: unable to execute command: Executable "" doesn't exist!
So we tell ChildProcess to expand argv[0] to the absolute path
to give them a helping hand.
