Auto merge of #135534 - folkertdev:fix-wasm-i128-f128, r=tgross35

use indirect return for `i128` and `f128` on wasm32

fixes #135532

Based on https://github.com/WebAssembly/tool-conventions/blob/main/BasicCABI.md we now use an indirect return for  `i128`, `u128` and `f128`. That is what LLVM ended up doing anyway.

r? `@bjorn3`

2 files changed, 98 insertions, 0 deletions

diff --git a/tests/codegen/f128-wasm32-callconv.rs b/tests/codegen/f128-wasm32-callconv.rs
new file mode 100644
index 00000000000..8b1b5e7fb01
--- /dev/null
+++ b/tests/codegen/f128-wasm32-callconv.rs
@@ -0,0 +1,49 @@
+//! Verify that Rust implements the expected calling convention for `f128`
+
+//@ add-core-stubs
+//@ compile-flags: -O --target wasm32-wasip1
+//@ needs-llvm-components: webassembly
+
+#![crate_type = "lib"]
+#![no_std]
+#![no_core]
+#![feature(no_core, lang_items, f128)]
+
+extern crate minicore;
+
+extern "C" {
+    fn extern_call(arg0: f128);
+    fn extern_ret() -> f128;
+}
+
+#[no_mangle]
+pub extern "C" fn pass(_arg0: u32, arg1: f128) {
+    // CHECK-LABEL: @pass(
+    // an f128 is passed via registers
+    // CHECK-SAME: fp128 noundef %arg1
+    // CHECK: call void @extern_call
+    unsafe { extern_call(arg1) };
+}
+
+// Check that we produce the correct return ABI
+#[no_mangle]
+pub extern "C" fn ret(_arg0: u32, arg1: f128) -> f128 {
+    // CHECK-LABEL: @ret(
+    // but an f128 is returned via the stack
+    // CHECK-SAME: sret
+    // CHECK: store fp128 %arg1
+    // CHECK-NEXT: ret void
+    arg1
+}
+
+// Check that we consume the correct return ABI
+#[no_mangle]
+pub extern "C" fn forward(dst: *mut f128) {
+    // CHECK-LABEL: @forward
+    // CHECK-SAME: ptr{{.*}} %dst)
+    // without optimizatons, an intermediate alloca is used
+    // CHECK: call void @extern_ret
+    // CHECK: store fp128
+    // CHECK: ret void
+    unsafe { *dst = extern_ret() };
+}
diff --git a/tests/codegen/i128-wasm32-callconv.rs b/tests/codegen/i128-wasm32-callconv.rs
new file mode 100644
index 00000000000..c6d25fbe8be
--- /dev/null
+++ b/tests/codegen/i128-wasm32-callconv.rs
@@ -0,0 +1,49 @@
+//! Verify that Rust implements the expected calling convention for `i128`/`u128`.
+
+//@ add-core-stubs
+//@ compile-flags: -O --target wasm32-wasip1
+//@ needs-llvm-components: webassembly
+
+#![crate_type = "lib"]
+#![no_std]
+#![no_core]
+#![feature(no_core, lang_items)]
+
+extern crate minicore;
+
+extern "C" {
+    fn extern_call(arg0: i128);
+    fn extern_ret() -> i128;
+}
+
+#[no_mangle]
+pub extern "C" fn pass(_arg0: u32, arg1: i128) {
+    // CHECK-LABEL: @pass(
+    // an i128 is passed via registers
+    // CHECK-SAME: i128 noundef %arg1
+    // CHECK: call void @extern_call
+    unsafe { extern_call(arg1) };
+}
+
+// Check that we produce the correct return ABI
+#[no_mangle]
+pub extern "C" fn ret(_arg0: u32, arg1: i128) -> i128 {
+    // CHECK-LABEL: @ret(
+    // but an i128 is returned via the stack
+    // CHECK-SAME: sret
+    // CHECK: store i128 %arg1
+    // CHECK-NEXT: ret void
+    arg1
+}
+
+// Check that we consume the correct return ABI
+#[no_mangle]
+pub extern "C" fn forward(dst: *mut i128) {
+    // CHECK-LABEL: @forward
+    // CHECK-SAME: ptr{{.*}} %dst)
+    // without optimizatons, an intermediate alloca is used
+    // CHECK: call void @extern_ret
+    // CHECK: store i128
+    // CHECK: ret void
+    unsafe { *dst = extern_ret() };
+}