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

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Stabilize Arm64EC inline assembly

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

Corresponding reference PR: https://github.com/rust-lang/reference/pull/1653

---

From the requirements of stabilization mentioned in https://github.com/rust-lang/rust/issues/93335

> Each architecture needs to be reviewed before stabilization:

> - It must have clobber_abi.

Done in https://github.com/rust-lang/rust/pull/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 https://github.com/rust-lang/rust/pull/131332#issuecomment-2401189142 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
This commit is contained in:
Matthias Krüger 2024-11-10 22:20:34 +01:00 committed by GitHub
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5 changed files with 6 additions and 33 deletions
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1
compiler/rustc_ast_lowering/src/asm.rs
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@ -45,6 +45,7 @@ pub(crate) fn lower_inline_asm(
| asm::InlineAsmArch::X86_64
| asm::InlineAsmArch::Arm
| asm::InlineAsmArch::AArch64
| asm::InlineAsmArch::Arm64EC
| asm::InlineAsmArch::RiscV32
| asm::InlineAsmArch::RiscV64
| asm::InlineAsmArch::LoongArch64

32
src/doc/unstable-book/src/language-features/asm-experimental-arch.md
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@ -18,7 +18,6 @@ This feature tracks `asm!` and `global_asm!` support for the following architect
- MSP430
- M68k
- CSKY
- Arm64EC
- SPARC
## Register classes
@ -53,9 +52,6 @@ This feature tracks `asm!` and `global_asm!` support for the following architect
| CSKY | `freg` | `f[0-31]` | `f` |
| SPARC | `reg` | `r[2-29]` | `r` |
| SPARC | `yreg` | `y` | Only clobbers |
| Arm64EC | `reg` | `x[0-12]`, `x[15-22]`, `x[25-27]`, `x30` | `r` |
| Arm64EC | `vreg` | `v[0-15]` | `w` |
| Arm64EC | `vreg_low16` | `v[0-15]` | `x` |
> **Notes**:
> - NVPTX doesn't have a fixed register set, so named registers are not supported.
@ -92,8 +88,6 @@ This feature tracks `asm!` and `global_asm!` support for the following architect
| CSKY | `freg` | None | `f32`, |
| SPARC | `reg` | None | `i8`, `i16`, `i32`, `i64` (SPARC64 only) |
| SPARC | `yreg` | N/A | Only clobbers |
| Arm64EC | `reg` | None | `i8`, `i16`, `i32`, `f32`, `i64`, `f64` |
| Arm64EC | `vreg` | None | `i8`, `i16`, `i32`, `f32`, `i64`, `f64`, <br> `i8x8`, `i16x4`, `i32x2`, `i64x1`, `f32x2`, `f64x1`, <br> `i8x16`, `i16x8`, `i32x4`, `i64x2`, `f32x4`, `f64x2` |
## Register aliases
@ -134,12 +128,6 @@ This feature tracks `asm!` and `global_asm!` support for the following architect
| SPARC | `r[8-15]` | `o[0-7]` |
| SPARC | `r[16-23]` | `l[0-7]` |
| SPARC | `r[24-31]` | `i[0-7]` |
| Arm64EC | `x[0-30]` | `w[0-30]` |
| Arm64EC | `x29` | `fp` |
| Arm64EC | `x30` | `lr` |
| Arm64EC | `sp` | `wsp` |
| Arm64EC | `xzr` | `wzr` |
| Arm64EC | `v[0-15]` | `b[0-15]`, `h[0-15]`, `s[0-15]`, `d[0-15]`, `q[0-15]` |
> **Notes**:
> - TI does not mandate a frame pointer for MSP430, but toolchains are allowed
@ -150,8 +138,8 @@ This feature tracks `asm!` and `global_asm!` support for the following architect
| Architecture | Unsupported register | Reason |
| ------------ | --------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| All | `sp`, `r14`/`o6` (SPARC) | The stack pointer must be restored to its original value at the end of an asm code block. |
| All | `fr` (Hexagon), `fp` (PowerPC), `$fp` (MIPS), `Y` (AVR), `r4` (MSP430), `a6` (M68k), `r30`/`i6` (SPARC), `x29` (Arm64EC) | The frame pointer cannot be used as an input or output. |
| All | `r19` (Hexagon), `r29` (PowerPC), `r30` (PowerPC), `x19` (Arm64EC) | These are used internally by LLVM as "base pointer" for functions with complex stack frames. |
| All | `fr` (Hexagon), `fp` (PowerPC), `$fp` (MIPS), `Y` (AVR), `r4` (MSP430), `a6` (M68k), `r30`/`i6` (SPARC) | The frame pointer cannot be used as an input or output. |
| All | `r19` (Hexagon), `r29` (PowerPC), `r30` (PowerPC) | These are used internally by LLVM as "base pointer" for functions with complex stack frames. |
| MIPS | `$0` or `$zero` | This is a constant zero register which can't be modified. |
| MIPS | `$1` or `$at` | Reserved for assembler. |
| MIPS | `$26`/`$k0`, `$27`/`$k1` | OS-reserved registers. |
@ -176,9 +164,6 @@ This feature tracks `asm!` and `global_asm!` support for the following architect
| SPARC | `r5`/`g5` | Reserved for system. (SPARC32 only) |
| SPARC | `r6`/`g6`, `r7`/`g7` | Reserved for system. |
| SPARC | `r31`/`i7` | Return address cannot be used as inputs or outputs. |
| Arm64EC | `xzr` | This is a constant zero register which can't be modified. |
| Arm64EC | `x18` | This is an OS-reserved register. |
| Arm64EC | `x13`, `x14`, `x23`, `x24`, `x28`, `v[16-31]` | These are AArch64 registers that are not supported for Arm64EC. |
## Template modifiers
@ -197,16 +182,6 @@ This feature tracks `asm!` and `global_asm!` support for the following architect
| SPARC | `reg` | None | `%o0` | None |
| CSKY | `reg` | None | `r0` | None |
| CSKY | `freg` | None | `f0` | None |
| Arm64EC | `reg` | None | `x0` | `x` |
| Arm64EC | `reg` | `w` | `w0` | `w` |
| Arm64EC | `reg` | `x` | `x0` | `x` |
| Arm64EC | `vreg` | None | `v0` | None |
| Arm64EC | `vreg` | `v` | `v0` | None |
| Arm64EC | `vreg` | `b` | `b0` | `b` |
| Arm64EC | `vreg` | `h` | `h0` | `h` |
| Arm64EC | `vreg` | `s` | `s0` | `s` |
| Arm64EC | `vreg` | `d` | `d0` | `d` |
| Arm64EC | `vreg` | `q` | `q0` | `q` |
# Flags covered by `preserves_flags`
@ -220,6 +195,3 @@ These flags registers must be restored upon exiting the asm block if the `preser
- SPARC
- Integer condition codes (`icc` and `xcc`)
- Floating-point condition codes (`fcc[0-3]`)
- Arm64EC
- Condition flags (`NZCV` register).
- Floating-point status (`FPSR` register).

2
tests/assembly/asm/aarch64-types.rs
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@ -6,7 +6,7 @@
//@ [arm64ec] needs-llvm-components: aarch64
//@ compile-flags: -Zmerge-functions=disabled
#![feature(no_core, lang_items, rustc_attrs, repr_simd, asm_experimental_arch, f16, f128)]
#![feature(no_core, lang_items, rustc_attrs, repr_simd, f16, f128)]
#![crate_type = "rlib"]
#![no_core]
#![allow(asm_sub_register, non_camel_case_types)]

2
tests/codegen/asm/arm64ec-clobbers.rs
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@ -3,7 +3,7 @@
//@ needs-llvm-components: aarch64
#![crate_type = "rlib"]
#![feature(no_core, rustc_attrs, lang_items, asm_experimental_arch)]
#![feature(no_core, rustc_attrs, lang_items)]
#![no_core]
#[lang = "sized"]

2
tests/ui/asm/aarch64/arm64ec-sve.rs
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@ -3,7 +3,7 @@
//@ needs-llvm-components: aarch64
#![crate_type = "rlib"]
#![feature(no_core, rustc_attrs, lang_items, asm_experimental_arch)]
#![feature(no_core, rustc_attrs, lang_items)]
#![no_core]
// SVE cannot be used for Arm64EC