Add arm64ec-pc-windows-msvc target

Cargo.lock

@@ -469,9 +469,9 @@ version = "0.1.0"
 
 [[package]]
 name = "cc"
-version = "1.0.79"
+version = "1.0.90"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "50d30906286121d95be3d479533b458f87493b30a4b5f79a607db8f5d11aa91f"
+checksum = "8cd6604a82acf3039f1144f54b8eb34e91ffba622051189e71b781822d5ee1f5"
 
 [[package]]
 name = "cfg-if"

compiler/rustc_codegen_llvm/src/back/archive.rs

@@ -55,6 +55,7 @@ fn llvm_machine_type(cpu: &str) -> LLVMMachineType {
         "x86_64" => LLVMMachineType::AMD64,
         "x86" => LLVMMachineType::I386,
         "aarch64" => LLVMMachineType::ARM64,
+        "arm64ec" => LLVMMachineType::ARM64EC,
         "arm" => LLVMMachineType::ARM,
         _ => panic!("unsupported cpu type {cpu}"),
     }

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -56,6 +56,7 @@ pub enum LLVMMachineType {
     AMD64 = 0x8664,
     I386 = 0x14c,
     ARM64 = 0xaa64,
+    ARM64EC = 0xa641,
     ARM = 0x01c0,
 }
 

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -201,7 +201,13 @@ impl<'a> IntoIterator for LLVMFeature<'a> {
 // which might lead to failures if the oldest tested / supported LLVM version
 // doesn't yet support the relevant intrinsics
 pub fn to_llvm_features<'a>(sess: &Session, s: &'a str) -> LLVMFeature<'a> {
-    let arch = if sess.target.arch == "x86_64" { "x86" } else { &*sess.target.arch };
+    let arch = if sess.target.arch == "x86_64" {
+        "x86"
+    } else if sess.target.arch == "arm64ec" {
+        "aarch64"
+    } else {
+        &*sess.target.arch
+    };
     match (arch, s) {
         ("x86", "sse4.2") => {
             LLVMFeature::with_dependency("sse4.2", TargetFeatureFoldStrength::EnableOnly("crc32"))

compiler/rustc_codegen_llvm/src/va_arg.rs

@@ -288,7 +288,7 @@ pub(super) fn emit_va_arg<'ll, 'tcx>(
         // Generic x86
         "x86" => emit_ptr_va_arg(bx, addr, target_ty, false, Align::from_bytes(4).unwrap(), true),
         // Windows AArch64
-        "aarch64" if target.is_like_windows => {
+        "aarch64" | "arm64ec" if target.is_like_windows => {
             emit_ptr_va_arg(bx, addr, target_ty, false, Align::from_bytes(8).unwrap(), false)
         }
         // macOS / iOS AArch64

compiler/rustc_codegen_ssa/Cargo.toml

@@ -7,7 +7,7 @@ edition = "2021"
 # tidy-alphabetical-start
 ar_archive_writer = "0.1.5"
 bitflags = "2.4.1"
-cc = "1.0.69"
+cc = "1.0.90"
 itertools = "0.11"
 jobserver = "0.1.28"
 pathdiff = "0.2.0"

compiler/rustc_codegen_ssa/src/back/metadata.rs

@@ -8,7 +8,7 @@ use std::path::Path;
 use object::write::{self, StandardSegment, Symbol, SymbolSection};
 use object::{
     elf, pe, xcoff, Architecture, BinaryFormat, Endianness, FileFlags, Object, ObjectSection,
-    ObjectSymbol, SectionFlags, SectionKind, SymbolFlags, SymbolKind, SymbolScope,
+    ObjectSymbol, SectionFlags, SectionKind, SubArchitecture, SymbolFlags, SymbolKind, SymbolScope,
 };
 
 use rustc_data_structures::memmap::Mmap;
@@ -182,37 +182,40 @@ pub(crate) fn create_object_file(sess: &Session) -> Option<write::Object<'static
         Endian::Little => Endianness::Little,
         Endian::Big => Endianness::Big,
     };
-    let architecture = match &sess.target.arch[..] {
-        "arm" => Architecture::Arm,
-        "aarch64" => {
+    let (architecture, sub_architecture) = match &sess.target.arch[..] {
+        "arm" => (Architecture::Arm, None),
+        "aarch64" => (
             if sess.target.pointer_width == 32 {
                 Architecture::Aarch64_Ilp32
             } else {
                 Architecture::Aarch64
-            }
-        }
-        "x86" => Architecture::I386,
-        "s390x" => Architecture::S390x,
-        "mips" | "mips32r6" => Architecture::Mips,
-        "mips64" | "mips64r6" => Architecture::Mips64,
-        "x86_64" => {
+            },
+            None,
+        ),
+        "x86" => (Architecture::I386, None),
+        "s390x" => (Architecture::S390x, None),
+        "mips" | "mips32r6" => (Architecture::Mips, None),
+        "mips64" | "mips64r6" => (Architecture::Mips64, None),
+        "x86_64" => (
             if sess.target.pointer_width == 32 {
                 Architecture::X86_64_X32
             } else {
                 Architecture::X86_64
-            }
-        }
-        "powerpc" => Architecture::PowerPc,
-        "powerpc64" => Architecture::PowerPc64,
-        "riscv32" => Architecture::Riscv32,
-        "riscv64" => Architecture::Riscv64,
-        "sparc64" => Architecture::Sparc64,
-        "avr" => Architecture::Avr,
-        "msp430" => Architecture::Msp430,
-        "hexagon" => Architecture::Hexagon,
-        "bpf" => Architecture::Bpf,
-        "loongarch64" => Architecture::LoongArch64,
-        "csky" => Architecture::Csky,
+            },
+            None,
+        ),
+        "powerpc" => (Architecture::PowerPc, None),
+        "powerpc64" => (Architecture::PowerPc64, None),
+        "riscv32" => (Architecture::Riscv32, None),
+        "riscv64" => (Architecture::Riscv64, None),
+        "sparc64" => (Architecture::Sparc64, None),
+        "avr" => (Architecture::Avr, None),
+        "msp430" => (Architecture::Msp430, None),
+        "hexagon" => (Architecture::Hexagon, None),
+        "bpf" => (Architecture::Bpf, None),
+        "loongarch64" => (Architecture::LoongArch64, None),
+        "csky" => (Architecture::Csky, None),
+        "arm64ec" => (Architecture::Aarch64, Some(SubArchitecture::Arm64EC)),
         // Unsupported architecture.
         _ => return None,
     };
@@ -227,6 +230,7 @@ pub(crate) fn create_object_file(sess: &Session) -> Option<write::Object<'static
     };
 
     let mut file = write::Object::new(binary_format, architecture, endianness);
+    file.set_sub_architecture(sub_architecture);
     if sess.target.is_like_osx {
         if macho_is_arm64e(&sess.target) {
             file.set_macho_cpu_subtype(object::macho::CPU_SUBTYPE_ARM64E);

compiler/rustc_codegen_ssa/src/back/symbol_export.rs

@@ -567,9 +567,10 @@ pub fn linking_symbol_name_for_instance_in_crate<'tcx>(
         return undecorated;
     }
 
-    let x86 = match &target.arch[..] {
-        "x86" => true,
-        "x86_64" => false,
+    let prefix = match &target.arch[..] {
+        "x86" => Some('_'),
+        "x86_64" => None,
+        "arm64ec" => Some('#'),
         // Only x86/64 use symbol decorations.
         _ => return undecorated,
     };
@@ -606,8 +607,8 @@ pub fn linking_symbol_name_for_instance_in_crate<'tcx>(
         Conv::X86Stdcall => ("_", "@"),
         Conv::X86VectorCall => ("", "@@"),
         _ => {
-            if x86 {
-                undecorated.insert(0, '_');
+            if let Some(prefix) = prefix {
+                undecorated.insert(0, prefix);
             }
             return undecorated;
         }

compiler/rustc_codegen_ssa/src/base.rs

@@ -907,7 +907,11 @@ impl CrateInfo {
                     lang_items::required(tcx, l).then_some(name)
                 })
                 .collect();
-            let prefix = if target.is_like_windows && target.arch == "x86" { "_" } else { "" };
+            let prefix = match (target.is_like_windows, target.arch.as_ref()) {
+                (true, "x86") => "_",
+                (true, "arm64ec") => "#",
+                _ => "",
+            };
 
             // This loop only adds new items to values of the hash map, so the order in which we
             // iterate over the values is not important.

compiler/rustc_llvm/Cargo.toml

@@ -8,12 +8,7 @@ edition = "2021"
 libc = "0.2.73"
 # tidy-alphabetical-end
 
-# FIXME: updating cc past 1.0.79 breaks libstd bootstrapping, pin
-# to the last working version here so `cargo update` doesn't cause the
-# a higher version to be selected
-# https://github.com/rust-lang/cc-rs/issues/913
-# 1.0.{84, 85} fix this but have been yanked
 [build-dependencies]
 # tidy-alphabetical-start
-cc = "=1.0.79"
+cc = "1.0.90"
 # tidy-alphabetical-end

compiler/rustc_target/src/abi/call/mod.rs

@@ -814,7 +814,7 @@ impl<'a, Ty> FnAbi<'a, Ty> {
                     }
                 }
             },
-            "aarch64" => {
+            "aarch64" | "arm64ec" => {
                 let kind = if cx.target_spec().is_like_osx {
                     aarch64::AbiKind::DarwinPCS
                 } else if cx.target_spec().is_like_windows {

compiler/rustc_target/src/spec/mod.rs

@@ -1564,6 +1564,7 @@ supported_targets! {
 
     ("aarch64-pc-windows-msvc", aarch64_pc_windows_msvc),
     ("aarch64-uwp-windows-msvc", aarch64_uwp_windows_msvc),
+    ("arm64ec-pc-windows-msvc", arm64ec_pc_windows_msvc),
     ("x86_64-pc-windows-msvc", x86_64_pc_windows_msvc),
     ("x86_64-uwp-windows-msvc", x86_64_uwp_windows_msvc),
     ("x86_64-win7-windows-msvc", x86_64_win7_windows_msvc),

compiler/rustc_target/src/spec/targets/arm64ec_pc_windows_msvc.rs

@@ -0,0 +1,21 @@
+use crate::spec::{add_link_args, base, LinkerFlavor, Lld, Target};
+
+pub fn target() -> Target {
+    let mut base = base::windows_msvc::opts();
+    base.max_atomic_width = Some(128);
+    base.features = "+v8a,+neon,+fp-armv8".into();
+    add_link_args(
+        &mut base.late_link_args,
+        LinkerFlavor::Msvc(Lld::No),
+        &["/machine:arm64ec", "softintrin.lib"],
+    );
+
+    Target {
+        llvm_target: "arm64ec-pc-windows-msvc".into(),
+        description: None,
+        pointer_width: 64,
+        data_layout: "e-m:w-p:64:64-i32:32-i64:64-i128:128-n32:64-S128".into(),
+        arch: "arm64ec".into(),
+        options: base,
+    }
+}

compiler/rustc_target/src/target_features.rs

@@ -409,7 +409,7 @@ impl super::spec::Target {
     pub fn supported_target_features(&self) -> &'static [(&'static str, Stability)] {
         match &*self.arch {
             "arm" => ARM_ALLOWED_FEATURES,
-            "aarch64" => AARCH64_ALLOWED_FEATURES,
+            "aarch64" | "arm64ec" => AARCH64_ALLOWED_FEATURES,
             "x86" | "x86_64" => X86_ALLOWED_FEATURES,
             "hexagon" => HEXAGON_ALLOWED_FEATURES,
             "mips" | "mips32r6" | "mips64" | "mips64r6" => MIPS_ALLOWED_FEATURES,
@@ -425,7 +425,7 @@ impl super::spec::Target {
 
     pub fn tied_target_features(&self) -> &'static [&'static [&'static str]] {
         match &*self.arch {
-            "aarch64" => AARCH64_TIED_FEATURES,
+            "aarch64" | "arm64ec" => AARCH64_TIED_FEATURES,
             _ => &[],
         }
     }

src/bootstrap/src/lib.rs

@@ -91,7 +91,7 @@ const EXTRA_CHECK_CFGS: &[(Option<Mode>, &str, Option<&[&'static str]>)] = &[
     /* Extra values not defined in the built-in targets yet, but used in std */
     (Some(Mode::Std), "target_env", Some(&["libnx", "p2"])),
     // (Some(Mode::Std), "target_os", Some(&[])),
-    (Some(Mode::Std), "target_arch", Some(&["spirv", "nvptx", "xtensa"])),
+    (Some(Mode::Std), "target_arch", Some(&["arm64ec", "spirv", "nvptx", "xtensa"])),
     /* Extra names used by dependencies */
     // FIXME: Used by serde_json, but we should not be triggering on external dependencies.
     (Some(Mode::Rustc), "no_btreemap_remove_entry", None),

src/doc/rustc/src/SUMMARY.md

@@ -18,6 +18,7 @@
     - [arm64e-apple-ios.md](platform-support/arm64e-apple-ios.md)
     - [arm64e-apple-darwin.md](platform-support/arm64e-apple-darwin.md)
     - [aarch64-apple-ios-sim](platform-support/aarch64-apple-ios-sim.md)
+    - [arm64ec-pc-windows-msvc](platform-support/arm64ec-pc-windows-msvc.md)
     - [\*-apple-tvos](platform-support/apple-tvos.md)
     - [\*-apple-watchos\*](platform-support/apple-watchos.md)
     - [aarch64-nintendo-switch-freestanding](platform-support/aarch64-nintendo-switch-freestanding.md)

src/doc/rustc/src/platform-support.md

@@ -241,6 +241,7 @@ target | std | host | notes
 -------|:---:|:----:|-------
 [`arm64e-apple-ios`](platform-support/arm64e-apple-ios.md) | ✓ | | ARM64e Apple iOS
 [`arm64e-apple-darwin`](platform-support/arm64e-apple-darwin.md)  | ✓ | ✓ | ARM64e Apple Darwin
+[`arm64ec-pc-windows-msvc`](platform-support/arm64ec-pc-windows-msvc.md) | ? | | Arm64EC Windows MSVC
 `aarch64-apple-ios-macabi` | ? |  | Apple Catalyst on ARM64
 [`aarch64-apple-tvos`](platform-support/apple-tvos.md) | ? |  | ARM64 tvOS
 [`aarch64-apple-tvos-sim`](platform-support/apple-tvos.md) | ? |  | ARM64 tvOS Simulator

src/doc/rustc/src/platform-support/arm64ec-pc-windows-msvc.md

@@ -0,0 +1,69 @@
+# `arm64ec-pc-windows-msvc`
+
+**Tier: 3**
+
+Arm64EC ("Emulation Compatible") for mixed architecture (AArch64 and x86_64)
+applications on AArch64 Windows 11. See <https://learn.microsoft.com/en-us/windows/arm/arm64ec>.
+
+## Target maintainers
+
+- [@dpaoliello](https://github.com/dpaoliello)
+
+## Requirements
+
+Target only supports cross-compilation, `core` and `alloc` are supported but
+`std` is not.
+
+Builds Arm64EC static and dynamic libraries and executables which can be run on
+AArch64 Windows 11 devices. Arm64EC static libraries can also be linked into
+Arm64X dynamic libraries and executables.
+
+Uses `arm64ec` as its `target_arch` - code built for Arm64EC must be compatible
+with x86_64 code (e.g., same structure layouts, function signatures, etc.) but
+use AArch64 intrinsics.
+
+Only supported backend is LLVM 18 (or above).
+
+## Building the target
+
+You can build Rust with support for the targets by adding it to the `target`
+list in `config.toml` and disabling `std`:
+
+```toml
+[build]
+target = [ "arm64ec-pc-windows-msvc" ]
+
+[target.arm64ec-pc-windows-msvc]
+no-std = true
+```
+
+## Building Rust programs
+
+Rust does not yet ship pre-compiled artifacts for this target. To compile for
+this target, you will either need to build Rust with the target enabled (see
+"Building the target" above), or build your own copy of `core` by using
+`build-std` or similar.
+
+## Testing
+
+Tests can be run on AArch64 Windows 11 devices.
+
+Since this is a `no_std` target, the Rust test suite is not supported.
+
+## Cross-compilation toolchains and C code
+
+C code can be built using the Arm64-targetting MSVC toolchain.
+
+To compile:
+
+```bash
+cl /arm64EC /c ...
+```
+
+To link:
+
+```bash
+link /MACHINE:ARM64EC ...
+```
+
+Further reading: <https://learn.microsoft.com/en-us/windows/arm/arm64ec-build>

tests/assembly/targets/targets-pe.rs

@@ -12,6 +12,9 @@
 //@ revisions: aarch64_uwp_windows_msvc
 //@ [aarch64_uwp_windows_msvc] compile-flags: --target aarch64-uwp-windows-msvc
 //@ [aarch64_uwp_windows_msvc] needs-llvm-components: aarch64
+//@ revisions: arm64ec_pc_windows_msvc
+//@ [arm64ec_pc_windows_msvc] compile-flags: --target arm64ec-pc-windows-msvc
+//@ [arm64ec_pc_windows_msvc] needs-llvm-components: aarch64
 //@ revisions: avr_unknown_gnu_atmega328
 //@ [avr_unknown_gnu_atmega328] compile-flags: --target avr-unknown-gnu-atmega328
 //@ [avr_unknown_gnu_atmega328] needs-llvm-components: avr

tests/ui/check-cfg/well-known-values.stderr

@@ -118,7 +118,7 @@ warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
 LL |     target_arch = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: expected values for `target_arch` are: `aarch64`, `arm`, `avr`, `bpf`, `csky`, `hexagon`, `loongarch64`, `m68k`, `mips`, `mips32r6`, `mips64`, `mips64r6`, `msp430`, `nvptx64`, `powerpc`, `powerpc64`, `riscv32`, `riscv64`, `s390x`, `sparc`, `sparc64`, `wasm32`, `wasm64`, `x86`, `x86_64`
+   = note: expected values for `target_arch` are: `aarch64`, `arm`, `arm64ec`, `avr`, `bpf`, `csky`, `hexagon`, `loongarch64`, `m68k`, `mips`, `mips32r6`, `mips64`, `mips64r6`, `msp430`, `nvptx64`, `powerpc`, `powerpc64`, `riscv32`, `riscv64`, `s390x`, `sparc`, `sparc64`, `wasm32`, `wasm64`, `x86`, `x86_64`
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`