…manieu,traviscross

Stabilize Arm64EC inline assembly

This stabilizes inline assembly for Arm64EC ("Emulation Compatible").

Corresponding reference PR: rust-lang/reference#1653

---

From the requirements of stabilization mentioned in rust-lang#93335

> Each architecture needs to be reviewed before stabilization:

> - It must have clobber_abi.

Done in rust-lang#131332.

> - It must be possible to clobber every register that is normally clobbered by a function call.

This is possible from the time of the initial implementation.

> - Generally review that the exposed register classes make sense.

The registers available in this target are a subset of those available in the AArch64 inline assembly which is already stable.

The following registers cannot be used in Arm64EC compared to AArch64:

- `x13`, `x14`, `x23`, `x24`, `x28` (register class: `reg`)
- `v[16-31]` (register class: `vreg`)
- `p[0-15]`, `ffr` (clobber-only register class `preg`)

These are disallowed by the ABI (see also [abi docs](https://learn.microsoft.com/en-us/cpp/build/arm64ec-windows-abi-conventions?view=msvc-170#register-mapping) for `reg`/`vreg` and rust-lang#131332 (comment) for `preg`).

Although not listed in the above requirements, preserves_flags is also implemented and the same as AArch64.

---

cc `@dpaoliello`

r? `@Amanieu`

`@rustbot` label O-windows O-AArch64 +A-inline-assembly +T-lang -T-compiler +needs-fcp

Rollup merge of rust-lang#131781 - taiki-e:arm64ec-stabilize-asm, r=Amanieu,traviscross

Stabilize Arm64EC inline assembly

This stabilizes inline assembly for Arm64EC ("Emulation Compatible").

Corresponding reference PR: rust-lang/reference#1653

---

From the requirements of stabilization mentioned in rust-lang#93335

> Each architecture needs to be reviewed before stabilization:

> - It must have clobber_abi.

Done in rust-lang#131332.

> - It must be possible to clobber every register that is normally clobbered by a function call.

This is possible from the time of the initial implementation.

> - Generally review that the exposed register classes make sense.

The registers available in this target are a subset of those available in the AArch64 inline assembly which is already stable.

The following registers cannot be used in Arm64EC compared to AArch64:

- `x13`, `x14`, `x23`, `x24`, `x28` (register class: `reg`)
- `v[16-31]` (register class: `vreg`)
- `p[0-15]`, `ffr` (clobber-only register class `preg`)

These are disallowed by the ABI (see also [abi docs](https://learn.microsoft.com/en-us/cpp/build/arm64ec-windows-abi-conventions?view=msvc-170#register-mapping) for `reg`/`vreg` and rust-lang#131332 (comment) for `preg`).

Although not listed in the above requirements, preserves_flags is also implemented and the same as AArch64.

---

cc `@dpaoliello`

r? `@Amanieu`

`@rustbot` label O-windows O-AArch64 +A-inline-assembly +T-lang -T-compiler +needs-fcp

…manieu,traviscross

Stabilize Arm64EC inline assembly

This stabilizes inline assembly for Arm64EC ("Emulation Compatible").

Corresponding reference PR: rust-lang/reference#1653

---

From the requirements of stabilization mentioned in rust-lang#93335

> Each architecture needs to be reviewed before stabilization:

> - It must have clobber_abi.

Done in rust-lang#131332.

> - It must be possible to clobber every register that is normally clobbered by a function call.

This is possible from the time of the initial implementation.

> - Generally review that the exposed register classes make sense.

The registers available in this target are a subset of those available in the AArch64 inline assembly which is already stable.

The following registers cannot be used in Arm64EC compared to AArch64:

- `x13`, `x14`, `x23`, `x24`, `x28` (register class: `reg`)
- `v[16-31]` (register class: `vreg`)
- `p[0-15]`, `ffr` (clobber-only register class `preg`)

These are disallowed by the ABI (see also [abi docs](https://learn.microsoft.com/en-us/cpp/build/arm64ec-windows-abi-conventions?view=msvc-170#register-mapping) for `reg`/`vreg` and rust-lang#131332 (comment) for `preg`).

Although not listed in the above requirements, preserves_flags is also implemented and the same as AArch64.

---

cc `@dpaoliello`

r? `@Amanieu`

`@rustbot` label O-windows O-AArch64 +A-inline-assembly +T-lang -T-compiler +needs-fcp