Check for asm support in UI tests that require it

Add `needs-asm-support` compiletest directive, and use it in asm tests
that require asm support without relying on any architecture specific
features.

src/tools/compiletest/src/header.rs

@@ -44,6 +44,7 @@ impl EarlyProps {
         let mut props = EarlyProps::default();
         let rustc_has_profiler_support = env::var_os("RUSTC_PROFILER_SUPPORT").is_some();
         let rustc_has_sanitizer_support = env::var_os("RUSTC_SANITIZER_SUPPORT").is_some();
+        let has_asm_support = util::has_asm_support(&config.target);
         let has_asan = util::ASAN_SUPPORTED_TARGETS.contains(&&*config.target);
         let has_lsan = util::LSAN_SUPPORTED_TARGETS.contains(&&*config.target);
         let has_msan = util::MSAN_SUPPORTED_TARGETS.contains(&&*config.target);
@@ -76,6 +77,10 @@ impl EarlyProps {
                     props.ignore = true;
                 }
 
+                if !has_asm_support && config.parse_name_directive(ln, "needs-asm-support") {
+                    props.ignore = true;
+                }
+
                 if !rustc_has_profiler_support && config.parse_needs_profiler_support(ln) {
                     props.ignore = true;
                 }

src/tools/compiletest/src/header/tests.rs

@@ -223,6 +223,17 @@ fn sanitizers() {
     assert!(parse_rs(&config, "// needs-sanitizer-thread").ignore);
 }
 
+#[test]
+fn asm_support() {
+    let mut config = config();
+
+    config.target = "avr-unknown-gnu-atmega328".to_owned();
+    assert!(parse_rs(&config, "// needs-asm-support").ignore);
+
+    config.target = "i686-unknown-netbsd".to_owned();
+    assert!(!parse_rs(&config, "// needs-asm-support").ignore);
+}
+
 #[test]
 fn test_extract_version_range() {
     use super::{extract_llvm_version, extract_version_range};

src/tools/compiletest/src/util.rs

@@ -128,6 +128,15 @@ const BIG_ENDIAN: &[&str] = &[
     "sparcv9",
 ];
 
+static ASM_SUPPORTED_ARCHS: &[&str] = &[
+    "x86", "x86_64", "arm", "aarch64", "riscv32", "riscv64", "nvptx64", "hexagon", "mips",
+    "mips64", "spirv", "wasm32",
+];
+
+pub fn has_asm_support(triple: &str) -> bool {
+    ASM_SUPPORTED_ARCHS.contains(&get_arch(triple))
+}
+
 pub fn matches_os(triple: &str, name: &str) -> bool {
     // For the wasm32 bare target we ignore anything also ignored on emscripten
     // and then we also recognize `wasm32-bare` as the os for the target