diff options
Diffstat (limited to 'src/test/ui/structs-enums/type-sizes.rs')
-rw-r--r-- | src/test/ui/structs-enums/type-sizes.rs | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/src/test/ui/structs-enums/type-sizes.rs b/src/test/ui/structs-enums/type-sizes.rs new file mode 100644 index 000000000..73a11a5e7 --- /dev/null +++ b/src/test/ui/structs-enums/type-sizes.rs @@ -0,0 +1,173 @@ +// run-pass + +#![allow(non_camel_case_types)] +#![allow(dead_code)] +#![feature(never_type)] + +use std::mem::size_of; +use std::num::NonZeroU8; + +struct t {a: u8, b: i8} +struct u {a: u8, b: i8, c: u8} +struct v {a: u8, b: i8, c: v2, d: u32} +struct v2 {u: char, v: u8} +struct w {a: isize, b: ()} +struct x {a: isize, b: (), c: ()} +struct y {x: isize} + +enum e1 { + a(u8, u32), b(u32), c +} +enum e2 { + a(u32), b +} + +#[repr(C, u8)] +enum e3 { + a([u16; 0], u8), b +} + +struct ReorderedStruct { + a: u8, + b: u16, + c: u8 +} + +enum ReorderedEnum { + A(u8, u16, u8), + B(u8, u16, u8), +} + +enum ReorderedEnum2 { + A(u8, u32, u8), + B(u16, u8, u16, u8), + + // 0x100 niche variants. + _00, _01, _02, _03, _04, _05, _06, _07, _08, _09, _0A, _0B, _0C, _0D, _0E, _0F, + _10, _11, _12, _13, _14, _15, _16, _17, _18, _19, _1A, _1B, _1C, _1D, _1E, _1F, + _20, _21, _22, _23, _24, _25, _26, _27, _28, _29, _2A, _2B, _2C, _2D, _2E, _2F, + _30, _31, _32, _33, _34, _35, _36, _37, _38, _39, _3A, _3B, _3C, _3D, _3E, _3F, + _40, _41, _42, _43, _44, _45, _46, _47, _48, _49, _4A, _4B, _4C, _4D, _4E, _4F, + _50, _51, _52, _53, _54, _55, _56, _57, _58, _59, _5A, _5B, _5C, _5D, _5E, _5F, + _60, _61, _62, _63, _64, _65, _66, _67, _68, _69, _6A, _6B, _6C, _6D, _6E, _6F, + _70, _71, _72, _73, _74, _75, _76, _77, _78, _79, _7A, _7B, _7C, _7D, _7E, _7F, + _80, _81, _82, _83, _84, _85, _86, _87, _88, _89, _8A, _8B, _8C, _8D, _8E, _8F, + _90, _91, _92, _93, _94, _95, _96, _97, _98, _99, _9A, _9B, _9C, _9D, _9E, _9F, + _A0, _A1, _A2, _A3, _A4, _A5, _A6, _A7, _A8, _A9, _AA, _AB, _AC, _AD, _AE, _AF, + _B0, _B1, _B2, _B3, _B4, _B5, _B6, _B7, _B8, _B9, _BA, _BB, _BC, _BD, _BE, _BF, + _C0, _C1, _C2, _C3, _C4, _C5, _C6, _C7, _C8, _C9, _CA, _CB, _CC, _CD, _CE, _CF, + _D0, _D1, _D2, _D3, _D4, _D5, _D6, _D7, _D8, _D9, _DA, _DB, _DC, _DD, _DE, _DF, + _E0, _E1, _E2, _E3, _E4, _E5, _E6, _E7, _E8, _E9, _EA, _EB, _EC, _ED, _EE, _EF, + _F0, _F1, _F2, _F3, _F4, _F5, _F6, _F7, _F8, _F9, _FA, _FB, _FC, _FD, _FE, _FF, +} + +enum EnumEmpty {} + +enum EnumSingle1 { + A, +} + +enum EnumSingle2 { + A = 42 as isize, +} + +enum EnumSingle3 { + A, + B(!), +} + +#[repr(u8)] +enum EnumSingle4 { + A, +} + +#[repr(u8)] +enum EnumSingle5 { + A = 42 as u8, +} + +enum EnumWithMaybeUninhabitedVariant<T> { + A(&'static ()), + B(&'static (), T), + C, +} + +enum NicheFilledEnumWithAbsentVariant { + A(&'static ()), + B((), !), + C, +} + +enum Option2<A, B> { + Some(A, B), + None +} + +// Two layouts are considered for `CanBeNicheFilledButShouldnt`: +// Niche-filling: +// { u32 (4 bytes), NonZeroU8 + tag in niche (1 byte), padding (3 bytes) } +// Tagged: +// { tag (1 byte), NonZeroU8 (1 byte), padding (2 bytes), u32 (4 bytes) } +// Both are the same size (due to padding), +// but the tagged layout is better as the tag creates a niche with 254 invalid values, +// allowing types like `Option<Option<CanBeNicheFilledButShouldnt>>` to fit into 8 bytes. +pub enum CanBeNicheFilledButShouldnt { + A(NonZeroU8, u32), + B +} +pub enum AlwaysTaggedBecauseItHasNoNiche { + A(u8, u32), + B +} + +pub fn main() { + assert_eq!(size_of::<u8>(), 1 as usize); + assert_eq!(size_of::<u32>(), 4 as usize); + assert_eq!(size_of::<char>(), 4 as usize); + assert_eq!(size_of::<i8>(), 1 as usize); + assert_eq!(size_of::<i32>(), 4 as usize); + assert_eq!(size_of::<t>(), 2 as usize); + assert_eq!(size_of::<u>(), 3 as usize); + // Alignment causes padding before the char and the u32. + + assert_eq!(size_of::<v>(), + 16 as usize); + assert_eq!(size_of::<isize>(), size_of::<usize>()); + assert_eq!(size_of::<w>(), size_of::<isize>()); + assert_eq!(size_of::<x>(), size_of::<isize>()); + assert_eq!(size_of::<isize>(), size_of::<y>()); + + // Make sure enum types are the appropriate size, mostly + // around ensuring alignment is handled properly + + assert_eq!(size_of::<e1>(), 8 as usize); + assert_eq!(size_of::<e2>(), 8 as usize); + assert_eq!(size_of::<e3>(), 4 as usize); + assert_eq!(size_of::<ReorderedStruct>(), 4); + assert_eq!(size_of::<ReorderedEnum>(), 6); + assert_eq!(size_of::<ReorderedEnum2>(), 8); + + + assert_eq!(size_of::<EnumEmpty>(), 0); + assert_eq!(size_of::<EnumSingle1>(), 0); + assert_eq!(size_of::<EnumSingle2>(), 0); + assert_eq!(size_of::<EnumSingle3>(), 0); + assert_eq!(size_of::<EnumSingle4>(), 1); + assert_eq!(size_of::<EnumSingle5>(), 1); + + assert_eq!(size_of::<EnumWithMaybeUninhabitedVariant<!>>(), + size_of::<EnumWithMaybeUninhabitedVariant<()>>()); + assert_eq!(size_of::<NicheFilledEnumWithAbsentVariant>(), size_of::<&'static ()>()); + + assert_eq!(size_of::<Option<Option<(bool, &())>>>(), size_of::<(bool, &())>()); + assert_eq!(size_of::<Option<Option<(&(), bool)>>>(), size_of::<(bool, &())>()); + assert_eq!(size_of::<Option<Option2<bool, &()>>>(), size_of::<(bool, &())>()); + assert_eq!(size_of::<Option<Option2<&(), bool>>>(), size_of::<(bool, &())>()); + + assert_eq!(size_of::<CanBeNicheFilledButShouldnt>(), 8); + assert_eq!(size_of::<Option<CanBeNicheFilledButShouldnt>>(), 8); + assert_eq!(size_of::<Option<Option<CanBeNicheFilledButShouldnt>>>(), 8); + assert_eq!(size_of::<AlwaysTaggedBecauseItHasNoNiche>(), 8); + assert_eq!(size_of::<Option<AlwaysTaggedBecauseItHasNoNiche>>(), 8); + assert_eq!(size_of::<Option<Option<AlwaysTaggedBecauseItHasNoNiche>>>(), 8); +} |