projects / rustc.git / blame
| Commit | Line | Data |
|---|---|---|
| ba9703b0 XL |
1 | //! Tests that generator discriminant sizes and ranges are chosen optimally and that they are |
| 2 | //! reflected in the output of `mem::discriminant`. | |
| 3 | ||
| 4 | // run-pass | |
| 5 | ||
| f9f354fc | 6 | #![feature(generators, generator_trait, core_intrinsics, discriminant_kind)] |
| ba9703b0 XL |
7 | |
| 8 | use std::intrinsics::discriminant_value; | |
| f9f354fc | 9 | use std::marker::{Unpin, DiscriminantKind}; |
| ba9703b0 XL |
10 | use std::mem::size_of_val; |
| 11 | use std::{cmp, ops::*}; | |
| 12 | ||
| 13 | macro_rules! yield25 { | |
| 14 | ($e:expr) => { | |
| 15 | yield $e; | |
| 16 | yield $e; | |
| 17 | yield $e; | |
| 18 | yield $e; | |
| 19 | yield $e; | |
| 20 | ||
| 21 | yield $e; | |
| 22 | yield $e; | |
| 23 | yield $e; | |
| 24 | yield $e; | |
| 25 | yield $e; | |
| 26 | ||
| 27 | yield $e; | |
| 28 | yield $e; | |
| 29 | yield $e; | |
| 30 | yield $e; | |
| 31 | yield $e; | |
| 32 | ||
| 33 | yield $e; | |
| 34 | yield $e; | |
| 35 | yield $e; | |
| 36 | yield $e; | |
| 37 | yield $e; | |
| 38 | ||
| 39 | yield $e; | |
| 40 | yield $e; | |
| 41 | yield $e; | |
| 42 | yield $e; | |
| 43 | yield $e; | |
| 44 | }; | |
| 45 | } | |
| 46 | ||
| 47 | /// Yields 250 times. | |
| 48 | macro_rules! yield250 { | |
| 49 | () => { | |
| 50 | yield250!(()) | |
| 51 | }; | |
| 52 | ||
| 53 | ($e:expr) => { | |
| 54 | yield25!($e); | |
| 55 | yield25!($e); | |
| 56 | yield25!($e); | |
| 57 | yield25!($e); | |
| 58 | yield25!($e); | |
| 59 | ||
| 60 | yield25!($e); | |
| 61 | yield25!($e); | |
| 62 | yield25!($e); | |
| 63 | yield25!($e); | |
| 64 | yield25!($e); | |
| 65 | }; | |
| 66 | } | |
| 67 | ||
| f9f354fc XL |
68 | fn cycle( |
| 69 | gen: impl Generator<()> + Unpin + DiscriminantKind<Discriminant = i32>, | |
| 70 | expected_max_discr: i32 | |
| 71 | ) { | |
| ba9703b0 XL |
72 | let mut gen = Box::pin(gen); |
| 73 | let mut max_discr = 0; | |
| 74 | loop { | |
| 75 | max_discr = cmp::max(max_discr, discriminant_value(gen.as_mut().get_mut())); | |
| 76 | match gen.as_mut().resume(()) { | |
| 77 | GeneratorState::Yielded(_) => {} | |
| 78 | GeneratorState::Complete(_) => { | |
| 79 | assert_eq!(max_discr, expected_max_discr); | |
| 80 | return; | |
| 81 | } | |
| 82 | } | |
| 83 | } | |
| 84 | } | |
| 85 | ||
| 86 | fn main() { | |
| 87 | // Has only one invalid discr. value. | |
| 88 | let gen_u8_tiny_niche = || { | |
| 89 | || { | |
| 90 | // 3 reserved variants | |
| 91 | ||
| 92 | yield250!(); // 253 variants | |
| 93 | ||
| 94 | yield; // 254 | |
| 95 | yield; // 255 | |
| 96 | } | |
| 97 | }; | |
| 98 | ||
| 99 | // Uses all values in the u8 discriminant. | |
| 100 | let gen_u8_full = || { | |
| 101 | || { | |
| 102 | // 3 reserved variants | |
| 103 | ||
| 104 | yield250!(); // 253 variants | |
| 105 | ||
| 106 | yield; // 254 | |
| 107 | yield; // 255 | |
| 108 | yield; // 256 | |
| 109 | } | |
| 110 | }; | |
| 111 | ||
| 112 | // Barely needs a u16 discriminant. | |
| 113 | let gen_u16 = || { | |
| 114 | || { | |
| 115 | // 3 reserved variants | |
| 116 | ||
| 117 | yield250!(); // 253 variants | |
| 118 | ||
| 119 | yield; // 254 | |
| 120 | yield; // 255 | |
| 121 | yield; // 256 | |
| 122 | yield; // 257 | |
| 123 | } | |
| 124 | }; | |
| 125 | ||
| 126 | assert_eq!(size_of_val(&gen_u8_tiny_niche()), 1); | |
| 127 | assert_eq!(size_of_val(&Some(gen_u8_tiny_niche())), 1); // uses niche | |
| 128 | assert_eq!(size_of_val(&Some(Some(gen_u8_tiny_niche()))), 2); // cannot use niche anymore | |
| 129 | assert_eq!(size_of_val(&gen_u8_full()), 1); | |
| 130 | assert_eq!(size_of_val(&Some(gen_u8_full())), 2); // cannot use niche | |
| 131 | assert_eq!(size_of_val(&gen_u16()), 2); | |
| 132 | assert_eq!(size_of_val(&Some(gen_u16())), 2); // uses niche | |
| 133 | ||
| 134 | cycle(gen_u8_tiny_niche(), 254); | |
| 135 | cycle(gen_u8_full(), 255); | |
| 136 | cycle(gen_u16(), 256); | |
| 137 | } |