mirror of https://github.com/rust-lang/rust
60 lines
1.1 KiB
Rust
60 lines
1.1 KiB
Rust
//@ compile-flags: -Z print-type-sizes --crate-type=lib
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//@ build-pass
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//@ ignore-pass
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// ^-- needed because `--pass check` does not emit the output needed.
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// FIXME: consider using an attribute instead of side-effects.
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// This file illustrates how packing is handled; it should cause
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// the elimination of padding that would normally be introduced
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// to satisfy alignment desirata.
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//
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// It avoids using u64/i64 because on some targets that is only 4-byte
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// aligned (while on most it is 8-byte aligned) and so the resulting
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// padding and overall computed sizes can be quite different.
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#![allow(dead_code)]
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#[derive(Default)]
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#[repr(packed)]
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pub struct Packed1 {
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a: u8,
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b: u8,
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g: i32,
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c: u8,
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h: i16,
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d: u8,
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}
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#[derive(Default)]
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#[repr(packed(2))]
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pub struct Packed2 {
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a: u8,
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b: u8,
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g: i32,
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c: u8,
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h: i16,
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d: u8,
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}
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#[derive(Default)]
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#[repr(packed(2))]
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#[repr(C)]
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pub struct Packed2C {
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a: u8,
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b: u8,
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g: i32,
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c: u8,
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h: i16,
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d: u8,
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}
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#[derive(Default)]
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pub struct Padded {
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a: u8,
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b: u8,
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g: i32,
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c: u8,
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h: i16,
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d: u8,
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}
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