src/test/codegen/repr-transparent.rs

// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

// compile-flags: -C no-prepopulate-passes

#![crate_type="lib"]
#![feature(repr_transparent, repr_simd)]

use std::marker::PhantomData;

pub struct Zst1;
pub struct Zst2(());

#[repr(transparent)]
pub struct F32(f32);

// CHECK: define float @test_F32(float %arg0)
#[no_mangle]
pub extern fn test_F32(_: F32) -> F32 { loop {} }

#[repr(transparent)]
pub struct Ptr(*mut u8);

// CHECK: define i8* @test_Ptr(i8* %arg0)
#[no_mangle]
pub extern fn test_Ptr(_: Ptr) -> Ptr { loop {} }

#[repr(transparent)]
pub struct WithZst(u64, Zst1);

// CHECK: define i64 @test_WithZst(i64 %arg0)
#[no_mangle]
pub extern fn test_WithZst(_: WithZst) -> WithZst { loop {} }

#[repr(transparent)]
pub struct WithZeroSizedArray(*const f32, [i8; 0]);

// Apparently we use i32* when newtype-unwrapping f32 pointers. Whatever.
// CHECK: define i32* @test_WithZeroSizedArray(i32* %arg0)
#[no_mangle]
pub extern fn test_WithZeroSizedArray(_: WithZeroSizedArray) -> WithZeroSizedArray { loop {} }

#[repr(transparent)]
pub struct Generic<T>(T);

// CHECK: define double @test_Generic(double %arg0)
#[no_mangle]
pub extern fn test_Generic(_: Generic<f64>) -> Generic<f64> { loop {} }

#[repr(transparent)]
pub struct GenericPlusZst<T>(T, Zst2);

#[repr(u8)]
pub enum Bool { True, False, FileNotFound }

// CHECK: define{{( zeroext)?}} i8 @test_Gpz(i8{{( zeroext)?}} %arg0)
#[no_mangle]
pub extern fn test_Gpz(_: GenericPlusZst<Bool>) -> GenericPlusZst<Bool> { loop {} }

#[repr(transparent)]
pub struct LifetimePhantom<'a, T: 'a>(*const T, PhantomData<&'a T>);

// CHECK: define i16* @test_LifetimePhantom(i16* %arg0)
#[no_mangle]
pub extern fn test_LifetimePhantom(_: LifetimePhantom<i16>) -> LifetimePhantom<i16> { loop {} }

// This works despite current alignment resrictions because PhantomData is always align(1)
#[repr(transparent)]
pub struct UnitPhantom<T, U> { val: T, unit: PhantomData<U> }

pub struct Px;

// CHECK: define float @test_UnitPhantom(float %arg0)
#[no_mangle]
pub extern fn test_UnitPhantom(_: UnitPhantom<f32, Px>) -> UnitPhantom<f32, Px> { loop {} }

#[repr(transparent)]
pub struct TwoZsts(Zst1, i8, Zst2);

// CHECK: define{{( signext)?}} i8 @test_TwoZsts(i8{{( signext)?}} %arg0)
#[no_mangle]
pub extern fn test_TwoZsts(_: TwoZsts) -> TwoZsts { loop {} }

#[repr(transparent)]
pub struct Nested1(Zst2, Generic<f64>);

// CHECK: define double @test_Nested1(double %arg0)
#[no_mangle]
pub extern fn test_Nested1(_: Nested1) -> Nested1 { loop {} }

#[repr(transparent)]
pub struct Nested2(Nested1, Zst1);

// CHECK: define double @test_Nested2(double %arg0)
#[no_mangle]
pub extern fn test_Nested2(_: Nested2) -> Nested2 { loop {} }

#[repr(simd)]
struct f32x4(f32, f32, f32, f32);

#[repr(transparent)]
pub struct Vector(f32x4);

// CHECK: define <4 x float> @test_Vector(<4 x float> %arg0)
#[no_mangle]
pub extern fn test_Vector(_: Vector) -> Vector { loop {} }

trait Mirror { type It: ?Sized; }
impl<T: ?Sized> Mirror for T { type It = Self; }

#[repr(transparent)]
pub struct StructWithProjection(<f32 as Mirror>::It);

// CHECK: define float @test_Projection(float %arg0)
#[no_mangle]
pub extern fn test_Projection(_: StructWithProjection) -> StructWithProjection { loop {} }


// The rest of this file tests newtypes around small aggregates on an ABI where small aggregates are
// packed into one register. This is ABI-dependent, so instead we focus on one ABI and supply a
// dummy definition for other ABIs to keep FileCheck happy.
//
// Bigger aggregates are tested in separate files called repr-transparent-aggregate-*.rs because
// there, the expected LLVM IR function signatures vary so much that it's not reasonably possible to
// cover all of them with a single CHECK line. Instead we group ABIs by the general "shape" of the
// signature and have a separate test file for each bin.
//
// PS: You may be wondering why we don't just compare the return types and argument types for
// equality with FileCheck regex captures. Well, rustc doesn't perform newtype unwrapping on
// newtypes containing aggregates. This is OK on all ABIs we support, but because LLVM has not
// gotten rid of pointee types yet, the IR function signature will be syntactically different (%Foo*
// vs %FooWrapper*).

#[repr(C)]
pub struct Rgb8 { r: u8, g: u8, b: u8 }

#[repr(transparent)]
pub struct Rgb8Wrap(Rgb8);

// NB: closing parenthesis is missing because sometimes the argument has a name and sometimes not
// CHECK: define i32 @test_Rgb8Wrap(i32
#[no_mangle]
#[cfg(all(target_arch="x86_64", target_os="linux"))]
pub extern fn test_Rgb8Wrap(_: Rgb8Wrap) -> Rgb8Wrap { loop {} }

#[cfg(not(all(target_arch="x86_64", target_os="linux")))]
#[no_mangle]
pub extern fn test_Rgb8Wrap(_: u32) -> u32 { loop {} }

// Same as with the small struct above: ABI-dependent, we only test the interesting case
// (ABIs that pack the aggregate into a scalar) and stub it out on other ABIs

#[repr(C)]
pub union FloatBits {
    float: f32,
    bits: u32,
}

#[repr(transparent)]
pub struct SmallUnion(FloatBits);

// NB: closing parenthesis is missing because sometimes the argument has a name and sometimes not
// CHECK: define i32 @test_SmallUnion(i32
#[no_mangle]
#[cfg(all(target_arch="x86_64", target_os="linux"))]
pub extern fn test_SmallUnion(_: SmallUnion) -> SmallUnion { loop {} }

#[cfg(not(all(target_arch="x86_64", target_os="linux")))]
#[no_mangle]
pub extern fn test_SmallUnion(_: u32) -> u32 { loop {} }