ABI checks: add support for tier2 arches

See #131800 for the data collection behind this change.

Also adds a test that exercise the "empty list of features" path.

Author: veluca93

compiler/rustc_target/src/target_features.rs

@@ -582,6 +582,14 @@ pub fn all_rust_features() -> impl Iterator<Item = (&'static str, Stability)> {
 const X86_FEATURES_FOR_CORRECT_VECTOR_ABI: &'static [(u64, &'static str)] =
     &[(128, "sse"), (256, "avx"), (512, "avx512f")];
 const AARCH64_FEATURES_FOR_CORRECT_VECTOR_ABI: &'static [(u64, &'static str)] = &[(128, "neon")];
+const ARM_FEATURES_FOR_CORRECT_VECTOR_ABI: &'static [(u64, &'static str)] = &[(128, "neon")];
+const POWERPC_FEATURES_FOR_CORRECT_VECTOR_ABI: &'static [(u64, &'static str)] = &[(128, "altivec")];
+const WASM_FEATURES_FOR_CORRECT_VECTOR_ABI: &'static [(u64, &'static str)] = &[(128, "simd128")];
+const S390X_FEATURES_FOR_CORRECT_VECTOR_ABI: &'static [(u64, &'static str)] = &[(128, "vector")];
+// Always warn on RISCV and SPARC, as the necessary target features cannot be enabled in Rust at
+// the moment.
+const RISCV_FEATURES_FOR_CORRECT_VECTOR_ABI: &'static [(u64, &'static str)] = &[];
+const SPARC_FEATURES_FOR_CORRECT_VECTOR_ABI: &'static [(u64, &'static str)] = &[];
 
 impl super::spec::Target {
     pub fn rust_target_features(&self) -> &'static [(&'static str, Stability, ImpliedFeatures)] {
@@ -606,9 +614,19 @@ impl super::spec::Target {
     // Returns None if we do not support ABI checks on the given target yet.
     pub fn features_for_correct_vector_abi(&self) -> Option<&'static [(u64, &'static str)]> {
         match &*self.arch {
+            // Tier 1
             "x86" | "x86_64" => Some(X86_FEATURES_FOR_CORRECT_VECTOR_ABI),
             "aarch64" => Some(AARCH64_FEATURES_FOR_CORRECT_VECTOR_ABI),
-            // FIXME: add support for non-tier1 architectures
+            // Tier 2
+            "arm64ec" => Some(AARCH64_FEATURES_FOR_CORRECT_VECTOR_ABI),
+            "arm" => Some(ARM_FEATURES_FOR_CORRECT_VECTOR_ABI),
+            "powerpc" | "powerpc64" => Some(POWERPC_FEATURES_FOR_CORRECT_VECTOR_ABI),
+            "loongarch64" => Some(&[]), // on-stack ABI, so we complain about all by-val vectors
+            "riscv32" | "riscv64" => Some(RISCV_FEATURES_FOR_CORRECT_VECTOR_ABI),
+            "wasm32" | "wasm64" => Some(WASM_FEATURES_FOR_CORRECT_VECTOR_ABI),
+            "s390x" => Some(S390X_FEATURES_FOR_CORRECT_VECTOR_ABI),
+            "sparc" | "sparc64" => Some(SPARC_FEATURES_FOR_CORRECT_VECTOR_ABI),
+            // FIXME: add support for non-tier2 architectures
             _ => None,
         }
     }

tests/ui/simd-abi-checks-empty-list.rs

@@ -0,0 +1,19 @@
+//@ needs-llvm-components: sparc
+//@ compile-flags: --target=sparc-unknown-none-elf --crate-type=rlib
+//@ build-pass
+//@ ignore-pass (test emits codegen-time warnings)
+#![no_core]
+#![feature(no_core, lang_items, repr_simd)]
+#![allow(improper_ctypes_definitions)]
+#[lang = "sized"]
+trait Sized {}
+
+#[lang = "copy"]
+trait Copy {}
+
+#[repr(simd)]
+pub struct SimdVec([i32; 4]);
+
+pub extern "C" fn pass_by_vec(_: SimdVec) {}
+//~^ ABI error: this function definition uses a vector type that requires the `<no available feature for this size>` target feature, which is not enabled
+//~| WARNING this was previously accepted by the compiler

tests/ui/simd-abi-checks-empty-list.stderr

@@ -0,0 +1,13 @@
+warning: ABI error: this function definition uses a vector type that requires the `<no available feature for this size>` target feature, which is not enabled
+  --> $DIR/simd-abi-checks-empty-list.rs:17:1
+   |
+LL | pub extern "C" fn pass_by_vec(_: SimdVec) {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ function defined here
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #116558 <https://github.com/rust-lang/rust/issues/116558>
+   = help: consider enabling it globally (`-C target-feature=+<no available feature for this size>`) or locally (`#[target_feature(enable="<no available feature for this size>")]`)
+   = note: `#[warn(abi_unsupported_vector_types)]` on by default
+
+warning: 1 warning emitted
+