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Windows x86: Change i128 to return via the vector ABI

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Clang and GCC both return `i128` in xmm0 on windows-msvc and
windows-gnu. Currently, Rust returns the type on the stack. Add a
calling convention adjustment so we also return scalar `i128`s using the
vector ABI, which makes our `i128` compatible with C.

In the future, Clang may change to return `i128` on the stack for its
`-msvc` targets (more at [1]). If this happens, the change here will
need to be adjusted to only affect MinGW.

Link: https://github.com/rust-lang/rust/issues/134288
This commit is contained in:
Trevor Gross
2024-12-14 00:32:39 +00:00
parent 581e0ac90c
commit a44a20ee4a
5 changed files with 44 additions and 67 deletions
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30
compiler/rustc_codegen_cranelift/src/codegen_i128.rs
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@@ -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,