Implement repr(transparent)

src/test/codegen/repr-transparent-aggregates-1.rs

@@ -0,0 +1,53 @@
+// 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
+
+// ignore-arm
+// ignore-mips
+// ignore-mips64
+// ignore-powerpc
+// ignore-powerpc64
+// See repr-transparent.rs
+
+#![crate_type="lib"]
+#![feature(repr_transparent)]
+
+
+#[repr(C)]
+pub struct Big([u32; 16]);
+
+#[repr(transparent)]
+pub struct BigW(Big);
+
+// CHECK: define void @test_Big(%Big* [[BIG_RET_ATTRS:.*]], %Big* [[BIG_ARG_ATTRS:.*]])
+#[no_mangle]
+pub extern fn test_Big(_: Big) -> Big { loop {} }
+
+// CHECK: define void @test_BigW(%BigW* [[BIG_RET_ATTRS]], %BigW* [[BIG_ARG_ATTRS]])
+#[no_mangle]
+pub extern fn test_BigW(_: BigW) -> BigW { loop {} }
+
+
+#[repr(C)]
+pub union BigU {
+    foo: [u32; 16],
+}
+
+#[repr(transparent)]
+pub struct BigUw(BigU);
+
+// CHECK: define void @test_BigU(%BigU* [[BIGU_RET_ATTRS:.*]], %BigU* [[BIGU_ARG_ATTRS:.*]])
+#[no_mangle]
+pub extern fn test_BigU(_: BigU) -> BigU { loop {} }
+
+// CHECK: define void @test_BigUw(%BigUw* [[BIGU_RET_ATTRS]], %BigUw* [[BIGU_ARG_ATTRS]])
+#[no_mangle]
+pub extern fn test_BigUw(_: BigUw) -> BigUw { loop {} }

src/test/codegen/repr-transparent-aggregates-2.rs

@@ -0,0 +1,54 @@
+// 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
+
+// ignore-aarch64
+// ignore-asmjs
+// ignore-s390x
+// ignore-wasm
+// ignore-x86
+// ignore-x86_64
+// See repr-transparent.rs
+
+#![crate_type="lib"]
+#![feature(repr_transparent)]
+
+
+#[repr(C)]
+pub struct Big([u32; 16]);
+
+#[repr(transparent)]
+pub struct BigW(Big);
+
+// CHECK: define void @test_Big(%Big* [[BIG_RET_ATTRS:.*]], [16 x i32]
+#[no_mangle]
+pub extern fn test_Big(_: Big) -> Big { loop {} }
+
+// CHECK: define void @test_BigW(%BigW* [[BIG_RET_ATTRS]], [16 x i32]
+#[no_mangle]
+pub extern fn test_BigW(_: BigW) -> BigW { loop {} }
+
+
+#[repr(C)]
+pub union BigU {
+    foo: [u32; 16],
+}
+
+#[repr(transparent)]
+pub struct BigUw(BigU);
+
+// CHECK: define void @test_BigU(%BigU* [[BIGU_RET_ATTRS:.*]], [16 x i32]
+#[no_mangle]
+pub extern fn test_BigU(_: BigU) -> BigU { loop {} }
+
+// CHECK: define void @test_BigUw(%BigUw* [[BIGU_RET_ATTRS]], [16 x i32]
+#[no_mangle]
+pub extern fn test_BigUw(_: BigUw) -> BigUw { loop {} }

src/test/codegen/repr-transparent.rs

@@ -0,0 +1,177 @@
+// 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 {} }

src/test/compile-fail/lint-ctypes.rs

@@ -9,10 +9,12 @@
 // except according to those terms.
 
 #![deny(improper_ctypes)]
-#![feature(libc, i128_type)]
+#![feature(libc, i128_type, repr_transparent)]
 
 extern crate libc;
 
+use std::marker::PhantomData;
+
 trait Mirror { type It: ?Sized; }
 impl<T: ?Sized> Mirror for T { type It = Self; }
 #[repr(C)]
@@ -28,6 +30,22 @@ pub type RustFn = fn();
 pub type RustBadRet = extern fn() -> Box<u32>;
 pub type CVoidRet = ();
 pub struct Foo;
+#[repr(transparent)]
+pub struct TransparentI128(i128);
+#[repr(transparent)]
+pub struct TransparentStr(&'static str);
+#[repr(transparent)]
+pub struct TransparentBadFn(RustBadRet);
+#[repr(transparent)]
+pub struct TransparentInt(u32);
+#[repr(transparent)]
+pub struct TransparentRef<'a>(&'a TransparentInt);
+#[repr(transparent)]
+pub struct TransparentLifetime<'a>(*const u8, PhantomData<&'a ()>);
+#[repr(transparent)]
+pub struct TransparentUnit<U>(f32, PhantomData<U>);
+#[repr(transparent)]
+pub struct TransparentCustomZst(i32, ZeroSize);
 
 #[repr(C)]
 pub struct ZeroSizeWithPhantomData(::std::marker::PhantomData<i32>);
@@ -51,6 +69,9 @@ extern {
     pub fn fn_type(p: RustFn); //~ ERROR found function pointer with Rust
     pub fn fn_type2(p: fn()); //~ ERROR found function pointer with Rust
     pub fn fn_contained(p: RustBadRet); //~ ERROR: found struct without
+    pub fn transparent_i128(p: TransparentI128); //~ ERROR: found Rust type `i128`
+    pub fn transparent_str(p: TransparentStr); //~ ERROR: found Rust type `str`
+    pub fn transparent_fn(p: TransparentBadFn); //~ ERROR: found struct without
 
     pub fn good3(fptr: Option<extern fn()>);
     pub fn good4(aptr: &[u8; 4 as usize]);
@@ -62,6 +83,11 @@ extern {
     pub fn good10() -> CVoidRet;
     pub fn good11(size: isize);
     pub fn good12(size: usize);
+    pub fn good13(n: TransparentInt);
+    pub fn good14(p: TransparentRef);
+    pub fn good15(p: TransparentLifetime);
+    pub fn good16(p: TransparentUnit<ZeroSize>);
+    pub fn good17(p: TransparentCustomZst);
 }
 
 #[cfg(not(target_arch = "wasm32"))]

src/test/compile-fail/repr-transparent-other-items.rs

@@ -0,0 +1,40 @@
+// 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.
+
+#![feature(repr_transparent)]
+
+// See also repr-transparent.rs
+
+#[repr(transparent)] //~ ERROR unsupported representation for zero-variant enum
+enum Void {}         //~| ERROR should be applied to struct
+
+#[repr(transparent)] //~ ERROR should be applied to struct
+enum FieldlessEnum {
+    Foo,
+    Bar,
+}
+
+#[repr(transparent)] //~ ERROR should be applied to struct
+enum Enum {
+    Foo(String),
+    Bar(u32),
+}
+
+#[repr(transparent)] //~ ERROR should be applied to struct
+union Foo {
+    u: u32,
+    s: i32
+}
+
+#[repr(transparent)] //~ ERROR should be applied to struct
+fn cant_repr_this() {}
+
+#[repr(transparent)] //~ ERROR should be applied to struct
+static CANT_REPR_THIS: u32 = 0;

src/test/compile-fail/repr-transparent-other-reprs.rs

@@ -0,0 +1,28 @@
+// 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.
+
+#![feature(repr_transparent, repr_align, attr_literals)]
+
+// See also repr-transparent.rs
+
+#[repr(transparent, C)] //~ ERROR cannot have other repr
+struct TransparentPlusC {
+    ptr: *const u8
+}
+
+#[repr(transparent, packed)] //~ ERROR cannot have other repr
+struct TransparentPlusPacked(*const u8);
+
+#[repr(transparent, align(2))] //~ ERROR cannot have other repr
+struct TransparentPlusAlign(u8);
+
+#[repr(transparent)] //~ ERROR cannot have other repr
+#[repr(C)]
+struct SeparateAttributes(*mut u8);

src/test/compile-fail/repr-transparent.rs

@@ -0,0 +1,51 @@
+// 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.
+
+// This file tests repr(transparent)-related errors reported during typeck. Other errors
+// that are reported earlier and therefore preempt these are tested in:
+// - repr-transparent-other-reprs.rs
+// - repr-transparent-other-items.rs
+
+#![feature(repr_align, attr_literals)]
+#![feature(repr_transparent)]
+
+use std::marker::PhantomData;
+
+#[repr(transparent)]
+struct NoFields; //~ ERROR needs exactly one non-zero-sized field
+
+#[repr(transparent)]
+struct ContainsOnlyZst(()); //~ ERROR needs exactly one non-zero-sized field
+
+#[repr(transparent)]
+struct ContainsOnlyZstArray([bool; 0]); //~ ERROR needs exactly one non-zero-sized field
+
+#[repr(transparent)]
+struct ContainsMultipleZst(PhantomData<*const i32>, NoFields);
+//~^ ERROR needs exactly one non-zero-sized field
+
+#[repr(transparent)]
+struct MultipleNonZst(u8, u8); //~ ERROR needs exactly one non-zero-sized field
+
+trait Mirror { type It: ?Sized; }
+impl<T: ?Sized> Mirror for T { type It = Self; }
+
+#[repr(transparent)]
+pub struct StructWithProjection(f32, <f32 as Mirror>::It);
+//~^ ERROR needs exactly one non-zero-sized field
+
+#[repr(transparent)]
+struct NontrivialAlignZst(u32, [u16; 0]); //~ ERROR alignment larger than 1
+
+#[repr(align(32))]
+struct ZstAlign32<T>(PhantomData<T>);
+
+#[repr(transparent)]
+struct GenericAlign<T>(ZstAlign32<T>, u32); //~ ERROR alignment larger than 1

src/test/ui/feature-gate-repr_transparent.rs

@@ -0,0 +1,14 @@
+// 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.
+
+#[repr(transparent)] //~ error: the `#[repr(transparent)]` attribute is experimental
+struct Foo(u64);
+
+fn main() {}

src/test/ui/feature-gate-repr_transparent.stderr

@@ -0,0 +1,10 @@
+error[E0658]: the `#[repr(transparent)]` attribute is experimental (see issue #43036)
+  --> $DIR/feature-gate-repr_transparent.rs:11:1
+   |
+11 | #[repr(transparent)] //~ error: the `#[repr(transparent)]` attribute is experimental
+   | ^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(repr_transparent)] to the crate attributes to enable
+
+error: aborting due to previous error
+