rust/tests/codegen/powerpc64le-struct-align-128.rs
Nikita Popov 009280c5e3 Fix argument ABI for overaligned structs on ppc64le
When passing a 16 (or higher) aligned struct by value on ppc64le,
it needs to be passed as an array of `i128` rather than an array
of `i64`. This will force the use of an even starting register.

For the case of a 16 byte struct with alignment 16 it is important
that `[1 x i128]` is used instead of `i128` -- apparently, the
latter will get treated similarly to `[2 x i64]`, not exhibiting
the correct ABI. Add a `force_array` flag to `Uniform` to support
this.

The relevant clang code can be found here:
fe2119a7b0/clang/lib/CodeGen/Targets/PPC.cpp (L878-L884)
fe2119a7b0/clang/lib/CodeGen/Targets/PPC.cpp (L780-L784)

I think the corresponding psABI wording is this:

> Fixed size aggregates and unions passed by value are mapped to as
> many doublewords of the parameter save area as the value uses in
> memory. Aggregrates and unions are aligned according to their
> alignment requirements. This may result in doublewords being
> skipped for alignment.

In particular the last sentence.

Fixes https://github.com/rust-lang/rust/issues/122767.
2024-04-08 11:15:36 +09:00

94 lines
1.7 KiB
Rust

// Test that structs aligned to 128 bits are passed with the correct ABI on powerpc64le.
// This is similar to aarch64-struct-align-128.rs, but for ppc.
//@ compile-flags: --target powerpc64le-unknown-linux-gnu
//@ needs-llvm-components: powerpc
#![feature(no_core, lang_items)]
#![crate_type = "lib"]
#![no_core]
#[lang="sized"]
trait Sized { }
#[lang="freeze"]
trait Freeze { }
#[lang="copy"]
trait Copy { }
#[repr(C)]
pub struct Align8 {
pub a: u64,
pub b: u64,
}
#[repr(transparent)]
pub struct Transparent8 {
a: Align8
}
#[repr(C)]
pub struct Wrapped8 {
a: Align8,
}
extern "C" {
// CHECK: declare void @test_8([2 x i64], [2 x i64], [2 x i64])
fn test_8(a: Align8, b: Transparent8, c: Wrapped8);
}
#[repr(C)]
#[repr(align(16))]
pub struct Align16 {
pub a: u64,
pub b: u64,
}
#[repr(transparent)]
pub struct Transparent16 {
a: Align16
}
#[repr(C)]
pub struct Wrapped16 {
pub a: Align16,
}
extern "C" {
// It's important that this produces [1 x i128] rather than just i128!
// CHECK: declare void @test_16([1 x i128], [1 x i128], [1 x i128])
fn test_16(a: Align16, b: Transparent16, c: Wrapped16);
}
#[repr(C)]
#[repr(align(32))]
pub struct Align32 {
pub a: u64,
pub b: u64,
pub c: u64,
}
#[repr(transparent)]
pub struct Transparent32 {
a: Align32
}
#[repr(C)]
pub struct Wrapped32 {
pub a: Align32,
}
extern "C" {
// CHECK: declare void @test_32([2 x i128], [2 x i128], [2 x i128])
fn test_32(a: Align32, b: Transparent32, c: Wrapped32);
}
pub unsafe fn main(
a1: Align8, a2: Transparent8, a3: Wrapped8,
b1: Align16, b2: Transparent16, b3: Wrapped16,
c1: Align32, c2: Transparent32, c3: Wrapped32,
) {
test_8(a1, a2, a3);
test_16(b1, b2, b3);
test_32(c1, c2, c3);
}