diff --git a/compiler/rustc_codegen_cranelift/src/abi/mod.rs b/compiler/rustc_codegen_cranelift/src/abi/mod.rs
index 2466bfe60c7ab..983584f58aba3 100644
--- a/compiler/rustc_codegen_cranelift/src/abi/mod.rs
+++ b/compiler/rustc_codegen_cranelift/src/abi/mod.rs
@@ -122,7 +122,7 @@ impl<'tcx> FunctionCx<'_, '_, 'tcx> {
&mut self,
name: &str,
params: Vec<AbiParam>,
- returns: Vec<AbiParam>,
+ mut returns: Vec<AbiParam>,
args: &[Value],
) -> Cow<'_, [Value]> {
// Pass i128 arguments by-ref on Windows.
@@ -146,15 +146,19 @@ impl<'tcx> FunctionCx<'_, '_, 'tcx> {
(params, args.into())
};
- // Return i128 using a return area pointer on Windows and s390x.
- let adjust_ret_param =
- if self.tcx.sess.target.is_like_windows || self.tcx.sess.target.arch == "s390x" {
- returns.len() == 1 && returns[0].value_type == types::I128
- } else {
- false
- };
+ let ret_single_i128 = returns.len() == 1 && returns[0].value_type == types::I128;
+ if ret_single_i128 && self.tcx.sess.target.is_like_windows {
+ // Return i128 using the vector ABI on Windows
+ returns[0].value_type = types::I64X2;
+
+ let ret = self.lib_call_unadjusted(name, params, returns, &args)[0];
- if adjust_ret_param {
+ // FIXME(bytecodealliance/wasmtime#6104) use bitcast instead of store to get from i64x2 to i128
+ let ret_ptr = self.create_stack_slot(16, 16);
+ ret_ptr.store(self, ret, MemFlags::trusted());
+ Cow::Owned(vec![ret_ptr.load(self, types::I128, MemFlags::trusted())])
+ } else if ret_single_i128 && self.tcx.sess.target.arch == "s390x" {
+ // Return i128 using a return area pointer on s390x.
let mut params = params;
let mut args = args.to_vec();
diff --git a/compiler/rustc_codegen_cranelift/src/cast.rs b/compiler/rustc_codegen_cranelift/src/cast.rs
index 0b5cb1547fc69..4463631c524be 100644
--- a/compiler/rustc_codegen_cranelift/src/cast.rs
+++ b/compiler/rustc_codegen_cranelift/src/cast.rs
@@ -96,25 +96,9 @@ pub(crate) fn clif_int_or_float_cast(
},
);
- if fx.tcx.sess.target.is_like_windows {
- let ret = fx.lib_call(
- &name,
- vec![AbiParam::new(from_ty)],
- vec![AbiParam::new(types::I64X2)],
- &[from],
- )[0];
- // FIXME(bytecodealliance/wasmtime#6104) use bitcast instead of store to get from i64x2 to i128
- let ret_ptr = fx.create_stack_slot(16, 16);
- ret_ptr.store(fx, ret, MemFlags::trusted());
- ret_ptr.load(fx, types::I128, MemFlags::trusted())
- } else {
- fx.lib_call(
- &name,
- vec![AbiParam::new(from_ty)],
- vec![AbiParam::new(types::I128)],
- &[from],
- )[0]
- }
+ fx.lib_call(&name, vec![AbiParam::new(from_ty)], vec![AbiParam::new(types::I128)], &[
+ from,
+ ])[0]
} else if to_ty == types::I8 || to_ty == types::I16 {
// FIXME implement fcvt_to_*int_sat.i8/i16
let val = if to_signed {
diff --git a/compiler/rustc_codegen_cranelift/src/codegen_i128.rs b/compiler/rustc_codegen_cranelift/src/codegen_i128.rs
index dcfd7ddabbc42..df5a79086fa3e 100644
--- a/compiler/rustc_codegen_cranelift/src/codegen_i128.rs
+++ b/compiler/rustc_codegen_cranelift/src/codegen_i128.rs
@@ -33,28 +33,14 @@ pub(crate) fn maybe_codegen<'tcx>(
(BinOp::Rem, true) => "__modti3",
_ => unreachable!(),
};
- if fx.tcx.sess.target.is_like_windows {
- let args = [lhs.load_scalar(fx), rhs.load_scalar(fx)];
- let ret = fx.lib_call(
- name,
- vec![AbiParam::new(types::I128), AbiParam::new(types::I128)],
- vec![AbiParam::new(types::I64X2)],
- &args,
- )[0];
- // FIXME(bytecodealliance/wasmtime#6104) use bitcast instead of store to get from i64x2 to i128
- let ret_place = CPlace::new_stack_slot(fx, lhs.layout());
- ret_place.to_ptr().store(fx, ret, MemFlags::trusted());
- Some(ret_place.to_cvalue(fx))
- } else {
- let args = [lhs.load_scalar(fx), rhs.load_scalar(fx)];
- let ret_val = fx.lib_call(
- name,
- vec![AbiParam::new(types::I128), AbiParam::new(types::I128)],
- vec![AbiParam::new(types::I128)],
- &args,
- )[0];
- Some(CValue::by_val(ret_val, lhs.layout()))
- }
+ let args = [lhs.load_scalar(fx), rhs.load_scalar(fx)];
+ let ret_val = fx.lib_call(
+ name,
+ vec![AbiParam::new(types::I128), AbiParam::new(types::I128)],
+ vec![AbiParam::new(types::I128)],
+ &args,
+ )[0];
+ Some(CValue::by_val(ret_val, lhs.layout()))
}
BinOp::Lt | BinOp::Le | BinOp::Eq | BinOp::Ge | BinOp::Gt | BinOp::Ne | BinOp::Cmp => None,
BinOp::Shl | BinOp::ShlUnchecked | BinOp::Shr | BinOp::ShrUnchecked => None,
diff --git a/compiler/rustc_target/src/callconv/x86_win64.rs b/compiler/rustc_target/src/callconv/x86_win64.rs
index 0944bda26875d..816564d2fed8b 100644
--- a/compiler/rustc_target/src/callconv/x86_win64.rs
+++ b/compiler/rustc_target/src/callconv/x86_win64.rs
@@ -1,4 +1,4 @@
-use rustc_abi::{BackendRepr, Float, Primitive};
+use rustc_abi::{BackendRepr, Float, Integer, Primitive, RegKind, Size};
use crate::abi::call::{ArgAbi, FnAbi, Reg};
use crate::spec::HasTargetSpec;
@@ -6,7 +6,7 @@ use crate::spec::HasTargetSpec;
// Win64 ABI: https://docs.microsoft.com/en-us/cpp/build/parameter-passing
pub(crate) fn compute_abi_info<Ty>(_cx: &impl HasTargetSpec, fn_abi: &mut FnAbi<'_, Ty>) {
- let fixup = |a: &mut ArgAbi<'_, Ty>| {
+ let fixup = |a: &mut ArgAbi<'_, Ty>, is_ret: bool| {
match a.layout.backend_repr {
BackendRepr::Uninhabited | BackendRepr::Memory { sized: false } => {}
BackendRepr::ScalarPair(..) | BackendRepr::Memory { sized: true } => {
@@ -23,11 +23,16 @@ pub(crate) fn compute_abi_info<Ty>(_cx: &impl HasTargetSpec, fn_abi: &mut FnAbi<
// (probably what clang calls "illegal vectors").
}
BackendRepr::Scalar(scalar) => {
- // Match what LLVM does for `f128` so that `compiler-builtins` builtins match up
- // with what LLVM expects.
- if a.layout.size.bytes() > 8
+ if is_ret && matches!(scalar.primitive(), Primitive::Int(Integer::I128, _)) {
+ // `i128` is returned in xmm0 by Clang and GCC
+ // FIXME(#134288): This may change for the `-msvc` targets in the future.
+ let reg = Reg { kind: RegKind::Vector, size: Size::from_bits(128) };
+ a.cast_to(reg);
+ } else if a.layout.size.bytes() > 8
&& !matches!(scalar.primitive(), Primitive::Float(Float::F128))
{
+ // Match what LLVM does for `f128` so that `compiler-builtins` builtins match up
+ // with what LLVM expects.
a.make_indirect();
} else {
a.extend_integer_width_to(32);
@@ -37,8 +42,9 @@ pub(crate) fn compute_abi_info<Ty>(_cx: &impl HasTargetSpec, fn_abi: &mut FnAbi<
};
if !fn_abi.ret.is_ignore() {
- fixup(&mut fn_abi.ret);
+ fixup(&mut fn_abi.ret, true);
}
+
for arg in fn_abi.args.iter_mut() {
if arg.is_ignore() && arg.layout.is_zst() {
// Windows ABIs do not talk about ZST since such types do not exist in MSVC.
@@ -49,7 +55,7 @@ pub(crate) fn compute_abi_info<Ty>(_cx: &impl HasTargetSpec, fn_abi: &mut FnAbi<
arg.make_indirect_from_ignore();
continue;
}
- fixup(arg);
+ fixup(arg, false);
}
// FIXME: We should likely also do something about ZST return types, similar to above.
// However, that's non-trivial due to `()`.
diff --git a/tests/codegen/i128-x86-callconv.rs b/tests/codegen/i128-x86-callconv.rs
new file mode 100644
index 0000000000000..9a9c9002fc026
--- /dev/null
+++ b/tests/codegen/i128-x86-callconv.rs
@@ -0,0 +1,79 @@
+//! Verify that Rust implements the expected calling convention for `i128`/`u128`.
+
+// Eliminate intermediate instructions during `nop` tests
+//@ compile-flags: -Copt-level=1
+
+//@ add-core-stubs
+//@ revisions: MSVC MINGW
+//@ [MSVC] needs-llvm-components: x86
+//@ [MINGW] needs-llvm-components: x86
+//@ [MSVC] compile-flags: --target x86_64-pc-windows-msvc
+//@ [MINGW] compile-flags: --target x86_64-pc-windows-gnu
+//@ [MSVC] filecheck-flags: --check-prefix=WIN
+//@ [MINGW] filecheck-flags: --check-prefix=WIN
+
+#![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(
+ // i128 is passed indirectly on Windows. It should load the pointer to the stack and pass
+ // a pointer to that allocation.
+ // WIN-SAME: %_arg0, ptr{{.*}} %arg1)
+ // WIN: [[PASS:%[_0-9]+]] = alloca [16 x i8], align 16
+ // WIN: [[LOADED:%[_0-9]+]] = load i128, ptr %arg1
+ // WIN: store i128 [[LOADED]], ptr [[PASS]]
+ // WIN: 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(
+ // i128 is returned in xmm0 on Windows
+ // FIXME(#134288): This may change for the `-msvc` targets in the future.
+ // WIN-SAME: i32{{.*}} %_arg0, ptr{{.*}} %arg1)
+ // WIN: [[LOADED:%[_0-9]+]] = load <16 x i8>, ptr %arg1
+ // WIN-NEXT: ret <16 x i8> [[LOADED]]
+ arg1
+}
+
+// Check that we consume the correct return ABI
+#[no_mangle]
+pub extern "C" fn forward(dst: *mut i128) {
+ // CHECK-LABEL: @forward
+ // WIN-SAME: ptr{{.*}} %dst)
+ // WIN: [[RETURNED:%[_0-9]+]] = tail call <16 x i8> @extern_ret()
+ // WIN: store <16 x i8> [[RETURNED]], ptr %dst
+ // WIN: ret void
+ unsafe { *dst = extern_ret() };
+}
+
+#[repr(C)]
+struct RetAggregate {
+ a: i32,
+ b: i128,
+}
+
+#[no_mangle]
+pub extern "C" fn ret_aggregate(_arg0: u32, arg1: i128) -> RetAggregate {
+ // CHECK-LABEL: @ret_aggregate(
+ // Aggregates should also be returned indirectly
+ // WIN-SAME: ptr{{.*}}sret([32 x i8]){{.*}}[[RET:%[_0-9]+]], i32{{.*}}%_arg0, ptr{{.*}}%arg1)
+ // WIN: [[LOADED:%[_0-9]+]] = load i128, ptr %arg1
+ // WIN: [[GEP:%[_0-9]+]] = getelementptr{{.*}}, ptr [[RET]]
+ // WIN: store i128 [[LOADED]], ptr [[GEP]]
+ // WIN: ret void
+ RetAggregate { a: 1, b: arg1 }
+}