Add Vega OS target (Tier 3)

compiler/rustc_target/src/spec/mod.rs

@@ -1705,6 +1705,10 @@ supported_targets! {
     ("riscv64-oe-linux-gnu", riscv64_oe_linux_gnu),
     ("x86_64-oe-linux-gnu", x86_64_oe_linux_gnu),
 
+    ("aarch64-vega-linux-gnu", aarch64_vega_linux_gnu),
+    ("armv7-vega-linux-gnueabihf", armv7_vega_linux_gnueabihf),
+    ("x86_64-vega-linux-gnu", x86_64_vega_linux_gnu),
+
     ("aarch64-unknown-hyperlight", aarch64_unknown_hyperlight),
     ("x86_64-unknown-hyperlight", x86_64_unknown_hyperlight),
 }

compiler/rustc_target/src/spec/targets/aarch64_vega_linux_gnu.rs

@@ -0,0 +1,16 @@
+use crate::spec::{Target, TargetMetadata, TargetOptions};
+
+pub(crate) fn target() -> Target {
+    let mut base = super::aarch64_unknown_linux_gnu::target();
+
+    base.metadata = TargetMetadata {
+        description: Some("ARM64 Vega OS (glibc 2.35)".into()),
+        tier: Some(3),
+        host_tools: Some(false),
+        std: Some(true),
+    };
+
+    base.options = TargetOptions { vendor: "vega".into(), ..base.options };
+
+    base
+}

compiler/rustc_target/src/spec/targets/armv7_vega_linux_gnueabihf.rs

@@ -0,0 +1,25 @@
+use crate::spec::{Target, TargetMetadata, TargetOptions};
+
+// The Vega OS armv7 userspace, including the SDK sysroot, is built for Cortex-A7
+// with NEON and VFPv4, so unlike armv7-unknown-linux-gnueabihf this target
+// assumes both.
+
+pub(crate) fn target() -> Target {
+    let mut base = super::armv7_unknown_linux_gnueabihf::target();
+
+    base.metadata = TargetMetadata {
+        description: Some("Armv7-A Vega OS, hardfloat, Cortex-A7 with NEON (glibc 2.35)".into()),
+        tier: Some(3),
+        host_tools: Some(false),
+        std: Some(true),
+    };
+
+    base.options = TargetOptions {
+        vendor: "vega".into(),
+        cpu: "cortex-a7".into(),
+        features: "+v7,+db,+dsp,+aclass,+perfmon,+vfp4,+neon,+thumb2".into(),
+        ..base.options
+    };
+
+    base
+}

compiler/rustc_target/src/spec/targets/x86_64_vega_linux_gnu.rs

@@ -0,0 +1,16 @@
+use crate::spec::{Target, TargetMetadata, TargetOptions};
+
+pub(crate) fn target() -> Target {
+    let mut base = super::x86_64_unknown_linux_gnu::target();
+
+    base.metadata = TargetMetadata {
+        description: Some("64-bit Vega OS (glibc 2.35)".into()),
+        tier: Some(3),
+        host_tools: Some(false),
+        std: Some(true),
+    };
+
+    base.options = TargetOptions { vendor: "vega".into(), ..base.options };
+
+    base
+}

library/unwind/src/lib.rs

@@ -171,7 +171,8 @@ unsafe extern "C" {}
     target_os = "linux",
     any(target_env = "gnu", target_env = "uclibc"),
     not(feature = "llvm-libunwind"),
-    not(feature = "system-llvm-libunwind")
+    not(feature = "system-llvm-libunwind"),
+    not(target_vendor = "vega")
 ))]
 #[link(name = "gcc_s", cfg(not(target_feature = "crt-static")))]
 unsafe extern "C" {}
@@ -180,11 +181,19 @@ unsafe extern "C" {}
     target_os = "linux",
     any(target_env = "gnu", target_env = "uclibc"),
     not(feature = "llvm-libunwind"),
-    feature = "system-llvm-libunwind"
+    feature = "system-llvm-libunwind",
+    not(target_vendor = "vega")
 ))]
 #[link(name = "unwind", cfg(not(target_feature = "crt-static")))]
 unsafe extern "C" {}
 
+// Vega OS has no shared `libgcc_s` for apps, so it always links LLVM's libunwind
+// statically. With `llvm-libunwind`, that is the in-tree copy (see `libunwind.rs`).
+// Otherwise, such as with `-Zbuild-std`, it is the `libunwind.a` in the Vega sysroot.
+#[cfg(all(target_vendor = "vega", not(feature = "llvm-libunwind")))]
+#[link(name = "unwind", kind = "static", modifiers = "-bundle")]
+unsafe extern "C" {}
+
 #[cfg(target_os = "redox")]
 #[link(name = "gcc_eh", kind = "static", modifiers = "-bundle", cfg(target_feature = "crt-static"))]
 #[link(name = "gcc_s", cfg(not(target_feature = "crt-static")))]

src/bootstrap/src/core/config/config.rs

@@ -1963,9 +1963,11 @@ NOTE: Please add `--stage 2` to your command line, or if you're sure you want to
             .unwrap_or(
                 if target.contains("fuchsia")
                     || (target.contains("hexagon") && !target.contains("qurt"))
+                    || target.contains("vega")
                 {
-                    // Fuchsia and Hexagon Linux use in-tree llvm-libunwind.
+                    // Fuchsia, Hexagon Linux and Vega OS use in-tree llvm-libunwind.
                     // Hexagon QuRT uses libc_eh from the Hexagon SDK instead.
+                    // Vega OS has no shared libgcc_s for apps.
                     LlvmLibunwind::InTree
                 } else {
                     LlvmLibunwind::No

src/bootstrap/src/core/sanity.rs

@@ -37,6 +37,9 @@ pub struct Finder {
 const STAGE0_MISSING_TARGETS: &[&str] = &[
     // just a dummy comment so the list doesn't get onelined
     "aarch64-unknown-qtee",
+    "aarch64-vega-linux-gnu",
+    "armv7-vega-linux-gnueabihf",
+    "x86_64-vega-linux-gnu",
 ];
 
 /// Minimum version threshold for libstdc++ required when using prebuilt LLVM

src/doc/rustc/src/SUMMARY.md

@@ -142,6 +142,7 @@
     - [\*-unknown-openbsd](platform-support/openbsd.md)
     - [\*-unknown-redox](platform-support/redox.md)
     - [\*-unknown-uefi](platform-support/unknown-uefi.md)
+    - [\*-vega-linux-gnu\*](platform-support/vega-linux-gnu.md)
     - [\*-pc-windows-msvc](platform-support/windows-msvc.md)
     - [\*-uwp-windows-msvc](platform-support/uwp-windows-msvc.md)
     - [\*-wrs-vxworks](platform-support/vxworks.md)

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

@@ -291,6 +291,7 @@ target | std | host | notes
 [`aarch64-unknown-qtee`](platform-support/aarch64-unknown-qtee.md) | ? |  | ARM64 QTEE |
 [`aarch64-unknown-trusty`](platform-support/trusty.md) | ✓ |  |
 [`aarch64-uwp-windows-msvc`](platform-support/uwp-windows-msvc.md) | ✓ |  |
+[`aarch64-vega-linux-gnu`](platform-support/vega-linux-gnu.md) | ✓ |  | ARM64 Vega OS (glibc 2.35)
 [`aarch64-wrs-vxworks`](platform-support/vxworks.md) | ✓ |  | ARM64 VxWorks OS
 [`aarch64v8r-unknown-none`](platform-support/aarch64v8r-unknown-none.md) | * | | Bare Armv8-R in AArch64 mode, hardfloat
 [`aarch64v8r-unknown-none-softfloat`](platform-support/aarch64v8r-unknown-none.md) | * | | Bare Armv8-R in AArch64 mode, softfloat
@@ -325,6 +326,7 @@ target | std | host | notes
 [`armv7-unknown-linux-uclibceabihf`](platform-support/armv7-unknown-linux-uclibceabihf.md) | ✓ | ? | Armv7-A Linux with uClibc, hardfloat
 [`armv7-unknown-netbsd-eabihf`](platform-support/netbsd.md) | ✓ | ✓ | Armv7-A NetBSD w/hard-float
 [`armv7-unknown-trusty`](platform-support/trusty.md) | ✓ |  |
+[`armv7-vega-linux-gnueabihf`](platform-support/vega-linux-gnu.md) | ✓ |  | Armv7-A Vega OS, hardfloat, Cortex-A7 with NEON (glibc 2.35)
 [`armv7-wrs-vxworks-eabihf`](platform-support/vxworks.md) | ✓ |  | Armv7-A for VxWorks
 [`armv7a-kmc-solid_asp3-eabi`](platform-support/kmc-solid.md) | ✓ |  | ARM SOLID with TOPPERS/ASP3
 [`armv7a-kmc-solid_asp3-eabihf`](platform-support/kmc-solid.md) | ✓ |  | ARM SOLID with TOPPERS/ASP3, hardfloat
@@ -473,6 +475,7 @@ target | std | host | notes
 [`x86_64-unknown-trusty`](platform-support/trusty.md) | ✓ |  |
 `x86_64-uwp-windows-gnu` | ✓ |  |
 [`x86_64-uwp-windows-msvc`](platform-support/uwp-windows-msvc.md) | ✓ |  |
+[`x86_64-vega-linux-gnu`](platform-support/vega-linux-gnu.md) | ✓ |  | 64-bit Vega OS (glibc 2.35)
 [`x86_64-win7-windows-gnu`](platform-support/win7-windows-gnu.md) | ✓ |  | 64-bit Windows 7 support
 [`x86_64-win7-windows-msvc`](platform-support/win7-windows-msvc.md) | ✓ | ✓ | 64-bit Windows 7 support
 [`x86_64-wrs-vxworks`](platform-support/vxworks.md) | ✓ |  |

src/doc/rustc/src/platform-support/vega-linux-gnu.md

@@ -0,0 +1,105 @@
+# `*-vega-linux-gnu*`
+
+**Tier: 3**
+
+Targets for [Vega OS], Amazon's Linux-based OS for Fire TV and other devices.
+
+[Vega OS]: https://developer.amazon.com/docs/vega/vega
+
+Target triplets available:
+
+- `aarch64-vega-linux-gnu`
+- `armv7-vega-linux-gnueabihf`
+- `x86_64-vega-linux-gnu`
+
+## Target maintainers
+
+[@aliiupeng](https://github.com/aliiupeng)
+[@altrieu-amazon](https://github.com/altrieu-amazon)
+
+## Requirements
+
+These targets only support cross-compilation. They support `std`.
+
+Vega OS is glibc-based Linux. Binaries built for these targets use the same Linux kernel
+interface, glibc ABI, ELF format and `extern "C"` calling convention as the corresponding
+`*-unknown-linux-gnu*` targets.
+
+- glibc 2.35 or newer.
+- There is no shared `libgcc_s`, so `std` for these targets links LLVM `libunwind`
+  statically: the in-tree copy when built with bootstrap (the default), or the Vega
+  sysroot's `libunwind.a` with `build-std`.
+- Every Rust shared library (`cdylib` or `dylib`) and the executable get their own copy of
+  the unwinder, so unwinding across a `.so` boundary isn't supported.
+- `armv7-vega-linux-gnueabihf` targets Cortex-A7 with NEON and VFPv4, which is what the
+  Vega OS userspace itself is built for. `armv7-unknown-linux-gnueabihf` assumes neither.
+
+The `cfg` values are the same as for the corresponding `*-unknown-linux-gnu*` targets but
+with `target_vendor = "vega"`, so code written that only checks os("linux") and env
+("gnu") for glibc Linux works as before.
+
+## Building the targets
+
+Add the targets to the `target` list in `bootstrap.toml`. Point each target's C toolchain
+at a clang that targets the Vega sysroot, such as the one in the Vega SDK:
+
+```toml
+[build]
+target = ["aarch64-vega-linux-gnu", "armv7-vega-linux-gnueabihf", "x86_64-vega-linux-gnu"]
+
+[target.aarch64-vega-linux-gnu]
+cc = "/path/to/vega-clang-aarch64"
+cxx = "/path/to/vega-clang++-aarch64"
+ar = "/path/to/llvm-ar"
+linker = "/path/to/vega-clang-aarch64"
+```
+
+`llvm-libunwind` defaults to `"in-tree"` for these targets.
+
+## Building Rust programs
+
+Rust does not yet ship pre-compiled artifacts for these targets. To compile for these
+targets, you will either need to build Rust with the targets enabled (see "Building the
+targets" above), or build your own copy of `std` by using `build-std` or similar.
+
+The Vega SDK provides a clang toolchain and sysroot for each architecture, and a Cargo
+configuration that sets the linker and sysroot. See [Install the Vega SDK].
+
+[Install the Vega SDK]: https://developer.amazon.com/docs/vega/0.24/install-vega-sdk
+
+To link without the SDK's configuration, use clang with these flags: `--target=<llvm-triple>
+--sysroot=<sysroot> -fuse-ld=lld -rtlib=compiler-rt -B<gcc-dir> -L<gcc-dir>`
+
+`<llvm-triple>` is the matching upstream triple (`aarch64-unknown-linux-gnu`,
+`armv7-unknown-linux-gnueabihf` or `x86_64-unknown-linux-gnu`).
+`<gcc-dir>` is the sysroot directory that holds GCC's `crtbeginS.o` and `libgcc.a`, which
+the sysroot keeps in an OpenEmbedded-style path,
+`<sysroot>/usr/lib/<oe-triple>/<gcc-version>/`.
+
+## Testing
+
+`x86_64-vega-linux-gnu` binaries run on a Linux x86_64 host using the host's glibc.
+`aarch64-vega-linux-gnu` and `armv7-vega-linux-gnueabihf` binaries run under
+`qemu-aarch64` / `qemu-arm` user-mode emulation with `-L` pointing at a Vega sysroot.
+
+Binaries can also run on the Vega Virtual Device (in the Vega SDK) when the binary's
+architecture matches the host's, or on Fire TV devices running Vega OS.
+
+The Rust test suite has not been run against these targets.
+
+## Cross-compilation toolchains and C code
+
+The targets support C and C++ code. Compile it with clang using the same `--target` and
+`--sysroot` as above. C++ code uses the sysroot's `libc++`.
+When Cargo builds C code through the `cc` crate, set these for each target (below is
+an example for `aarch64-vega-linux-gnu`):
+
+```sh
+CC_aarch64_vega_linux_gnu=/path/to/clang
+AR_aarch64_vega_linux_gnu=/path/to/llvm-ar
+CFLAGS_aarch64_vega_linux_gnu="--sysroot=<vega-sysroot-aarch64>"
+```
+
+`cc` passes `--target=<Rust target name>` to clang, which accepts the `vega` vendor.
+For `armv7-vega-linux-gnueabihf`, also add `-mcpu=cortex-a7 -mfpu=neon-vfpv4` to
+`CFLAGS_armv7_vega_linux_gnueabihf`.

tests/assembly-llvm/targets/targets-elf.rs

@@ -79,6 +79,9 @@
 //@ revisions: aarch64_unknown_none_softfloat
 //@ [aarch64_unknown_none_softfloat] compile-flags: --target aarch64-unknown-none-softfloat
 //@ [aarch64_unknown_none_softfloat] needs-llvm-components: aarch64
+//@ revisions: aarch64_vega_linux_gnu
+//@ [aarch64_vega_linux_gnu] compile-flags: --target aarch64-vega-linux-gnu
+//@ [aarch64_vega_linux_gnu] needs-llvm-components: aarch64
 //@ revisions: aarch64v8r_unknown_none
 //@ [aarch64v8r_unknown_none] compile-flags: --target aarch64v8r-unknown-none
 //@ [aarch64v8r_unknown_none] needs-llvm-components: aarch64
@@ -217,6 +220,9 @@
 //@ revisions: armv7_unknown_trusty
 //@ [armv7_unknown_trusty] compile-flags: --target armv7-unknown-trusty
 //@ [armv7_unknown_trusty] needs-llvm-components: arm
+//@ revisions: armv7_vega_linux_gnueabihf
+//@ [armv7_vega_linux_gnueabihf] compile-flags: --target armv7-vega-linux-gnueabihf
+//@ [armv7_vega_linux_gnueabihf] needs-llvm-components: arm
 //@ revisions: armv7_wrs_vxworks_eabihf
 //@ [armv7_wrs_vxworks_eabihf] compile-flags: --target armv7-wrs-vxworks-eabihf
 //@ [armv7_wrs_vxworks_eabihf] needs-llvm-components: arm
@@ -784,6 +790,9 @@
 //@ revisions: x86_64_unknown_trusty
 //@ [x86_64_unknown_trusty] compile-flags: --target x86_64-unknown-trusty
 //@ [x86_64_unknown_trusty] needs-llvm-components: x86
+//@ revisions: x86_64_vega_linux_gnu
+//@ [x86_64_vega_linux_gnu] compile-flags: --target x86_64-vega-linux-gnu
+//@ [x86_64_vega_linux_gnu] needs-llvm-components: x86
 //@ revisions: x86_64_wrs_vxworks
 //@ [x86_64_wrs_vxworks] compile-flags: --target x86_64-wrs-vxworks
 //@ [x86_64_wrs_vxworks] needs-llvm-components: x86

tests/ui/check-cfg/exhaustive-names-values.empty_cfg.stderr

@@ -14,7 +14,7 @@ warning: unexpected `cfg` condition value: `value`
 LL | #[cfg(target_vendor = "value")]
    |       ^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: expected values for `target_vendor` are: `amd`, `apple`, `espressif`, `fortanix`, `ibm`, `kmc`, `mti`, `nintendo`, `nvidia`, `openwrt`, `pc`, `risc0`, `sony`, `sun`, `unikraft`, `unknown`, `uwp`, `vex`, `win7`, and `wrs`
+   = note: expected values for `target_vendor` are: `amd`, `apple`, `espressif`, `fortanix`, `ibm`, `kmc`, `mti`, `nintendo`, `nvidia`, `openwrt`, `pc`, `risc0`, `sony`, `sun`, `unikraft`, `unknown`, `uwp`, `vega`, `vex`, `win7`, and `wrs`
    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition name: `feature`

tests/ui/check-cfg/exhaustive-names-values.feature.stderr

@@ -15,7 +15,7 @@ warning: unexpected `cfg` condition value: `value`
 LL | #[cfg(target_vendor = "value")]
    |       ^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: expected values for `target_vendor` are: `amd`, `apple`, `espressif`, `fortanix`, `ibm`, `kmc`, `mti`, `nintendo`, `nvidia`, `openwrt`, `pc`, `risc0`, `sony`, `sun`, `unikraft`, `unknown`, `uwp`, `vex`, `win7`, and `wrs`
+   = note: expected values for `target_vendor` are: `amd`, `apple`, `espressif`, `fortanix`, `ibm`, `kmc`, `mti`, `nintendo`, `nvidia`, `openwrt`, `pc`, `risc0`, `sony`, `sun`, `unikraft`, `unknown`, `uwp`, `vega`, `vex`, `win7`, and `wrs`
    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `unk`

tests/ui/check-cfg/exhaustive-names-values.full.stderr

@@ -15,7 +15,7 @@ warning: unexpected `cfg` condition value: `value`
 LL | #[cfg(target_vendor = "value")]
    |       ^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: expected values for `target_vendor` are: `amd`, `apple`, `espressif`, `fortanix`, `ibm`, `kmc`, `mti`, `nintendo`, `nvidia`, `openwrt`, `pc`, `risc0`, `sony`, `sun`, `unikraft`, `unknown`, `uwp`, `vex`, `win7`, and `wrs`
+   = note: expected values for `target_vendor` are: `amd`, `apple`, `espressif`, `fortanix`, `ibm`, `kmc`, `mti`, `nintendo`, `nvidia`, `openwrt`, `pc`, `risc0`, `sony`, `sun`, `unikraft`, `unknown`, `uwp`, `vega`, `vex`, `win7`, and `wrs`
    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `unk`

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

@@ -261,7 +261,7 @@ warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
 LL |     target_vendor = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: expected values for `target_vendor` are: `amd`, `apple`, `espressif`, `fortanix`, `ibm`, `kmc`, `mti`, `nintendo`, `nvidia`, `openwrt`, `pc`, `risc0`, `sony`, `sun`, `unikraft`, `unknown`, `uwp`, `vex`, `win7`, and `wrs`
+   = note: expected values for `target_vendor` are: `amd`, `apple`, `espressif`, `fortanix`, `ibm`, `kmc`, `mti`, `nintendo`, `nvidia`, `openwrt`, `pc`, `risc0`, `sony`, `sun`, `unikraft`, `unknown`, `uwp`, `vega`, `vex`, `win7`, and `wrs`
    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`