wasm: Make simd types passed via indirection again

compiler/rustc_target/src/spec/wasm_base.rs

@@ -103,12 +103,6 @@ pub fn options() -> TargetOptions {
         linker: Some("rust-lld".to_owned()),
         lld_flavor: LldFlavor::Wasm,
 
-        // No need for indirection here, simd types can always be passed by
-        // value as the whole module either has simd or not, which is different
-        // from x86 (for example) where programs can have functions that don't
-        // enable simd features.
-        simd_types_indirect: false,
-
         pre_link_args,
 
         crt_objects_fallback: Some(CrtObjectsFallback::Wasm),

src/test/ui/simd/wasm-simd-indirect.rs

@@ -0,0 +1,33 @@
+// build-pass
+
+#![cfg_attr(target_arch = "wasm32", feature(wasm_simd, wasm_target_feature))]
+
+#[cfg(target_arch = "wasm32")]
+fn main() {
+    unsafe {
+        a::api_with_simd_feature();
+    }
+}
+
+#[cfg(target_arch = "wasm32")]
+mod a {
+    use std::arch::wasm32::*;
+
+    #[target_feature(enable = "simd128")]
+    pub unsafe fn api_with_simd_feature() {
+        crate::b::api_takes_v128(u64x2(0, 1));
+    }
+}
+
+#[cfg(target_arch = "wasm32")]
+mod b {
+    use std::arch::wasm32::*;
+
+    #[inline(never)]
+    pub fn api_takes_v128(a: v128) -> v128 {
+        a
+    }
+}
+
+#[cfg(not(target_arch = "wasm32"))]
+fn main() {}