compiler/rustc_codegen_gcc/example/mini_core_hello_world.rs

   1 // Adapted from https://github.com/sunfishcode/mir2cranelift/blob/master/rust-examples/nocore-hello-world.rs
   2
   3 #![feature(
   4     no_core, unboxed_closures, start, lang_items, box_syntax, never_type, linkage,
   5     extern_types, thread_local
   6 )]
   7 #![no_core]
   8 #![allow(dead_code, non_camel_case_types)]
   9
  10 extern crate mini_core;
  11
  12 use mini_core::*;
  13 use mini_core::libc::*;
  14
  15 unsafe extern "C" fn my_puts(s: *const u8) {
  16     puts(s);
  17 }
  18
  19 #[lang = "termination"]
  20 trait Termination {
  21     fn report(self) -> i32;
  22 }
  23
  24 impl Termination for () {
  25     fn report(self) -> i32 {
  26         unsafe {
  27             NUM = 6 * 7 + 1 + (1u8 == 1u8) as u8; // 44
  28             *NUM_REF as i32
  29         }
  30     }
  31 }
  32
  33 trait SomeTrait {
  34     fn object_safe(&self);
  35 }
  36
  37 impl SomeTrait for &'static str {
  38     fn object_safe(&self) {
  39         unsafe {
  40             puts(*self as *const str as *const u8);
  41         }
  42     }
  43 }
  44
  45 struct NoisyDrop {
  46     text: &'static str,
  47     inner: NoisyDropInner,
  48 }
  49
  50 struct NoisyDropUnsized {
  51     inner: NoisyDropInner,
  52     text: str,
  53 }
  54
  55 struct NoisyDropInner;
  56
  57 impl Drop for NoisyDrop {
  58     fn drop(&mut self) {
  59         unsafe {
  60             puts(self.text as *const str as *const u8);
  61         }
  62     }
  63 }
  64
  65 impl Drop for NoisyDropInner {
  66     fn drop(&mut self) {
  67         unsafe {
  68             puts("Inner got dropped!\0" as *const str as *const u8);
  69         }
  70     }
  71 }
  72
  73 impl SomeTrait for NoisyDrop {
  74     fn object_safe(&self) {}
  75 }
  76
  77 enum Ordering {
  78     Less = -1,
  79     Equal = 0,
  80     Greater = 1,
  81 }
  82
  83 #[lang = "start"]
  84 fn start<T: Termination + 'static>(
  85     main: fn() -> T,
  86     argc: isize,
  87     argv: *const *const u8,
  88 ) -> isize {
  89     if argc == 3 {
  90         unsafe { puts(*argv); }
  91         unsafe { puts(*((argv as usize + intrinsics::size_of::<*const u8>()) as *const *const u8)); }
  92         unsafe { puts(*((argv as usize + 2 * intrinsics::size_of::<*const u8>()) as *const *const u8)); }
  93     }
  94
  95     main().report();
  96     0
  97 }
  98
  99 static mut NUM: u8 = 6 * 7;
 100 static NUM_REF: &'static u8 = unsafe { &NUM };
 101
 102 macro_rules! assert {
 103     ($e:expr) => {
 104         if !$e {
 105             panic(stringify!(! $e));
 106         }
 107     };
 108 }
 109
 110 macro_rules! assert_eq {
 111     ($l:expr, $r: expr) => {
 112         if $l != $r {
 113             panic(stringify!($l != $r));
 114         }
 115     }
 116 }
 117
 118 struct Unique<T: ?Sized> {
 119     pointer: *const T,
 120     _marker: PhantomData<T>,
 121 }
 122
 123 impl<T: ?Sized, U: ?Sized> CoerceUnsized<Unique<U>> for Unique<T> where T: Unsize<U> {}
 124
 125 unsafe fn zeroed<T>() -> T {
 126     let mut uninit = MaybeUninit { uninit: () };
 127     intrinsics::write_bytes(&mut uninit.value.value as *mut T, 0, 1);
 128     uninit.value.value
 129 }
 130
 131 fn take_f32(_f: f32) {}
 132 fn take_unique(_u: Unique<()>) {}
 133
 134 fn return_u128_pair() -> (u128, u128) {
 135     (0, 0)
 136 }
 137
 138 fn call_return_u128_pair() {
 139     return_u128_pair();
 140 }
 141
 142 fn main() {
 143     take_unique(Unique {
 144         pointer: 0 as *const (),
 145         _marker: PhantomData,
 146     });
 147     take_f32(0.1);
 148
 149     //call_return_u128_pair();
 150
 151     let slice = &[0, 1] as &[i32];
 152     let slice_ptr = slice as *const [i32] as *const i32;
 153
 154     assert_eq!(slice_ptr as usize % 4, 0);
 155
 156     //return;
 157
 158     unsafe {
 159         printf("Hello %s\n\0" as *const str as *const i8, "printf\0" as *const str as *const i8);
 160
 161         let hello: &[u8] = b"Hello\0" as &[u8; 6];
 162         let ptr: *const u8 = hello as *const [u8] as *const u8;
 163         puts(ptr);
 164
 165         let world: Box<&str> = box "World!\0";
 166         puts(*world as *const str as *const u8);
 167         world as Box<dyn SomeTrait>;
 168
 169         assert_eq!(intrinsics::bitreverse(0b10101000u8), 0b00010101u8);
 170
 171         assert_eq!(intrinsics::bswap(0xabu8), 0xabu8);
 172         assert_eq!(intrinsics::bswap(0xddccu16), 0xccddu16);
 173         assert_eq!(intrinsics::bswap(0xffee_ddccu32), 0xccdd_eeffu32);
 174         assert_eq!(intrinsics::bswap(0x1234_5678_ffee_ddccu64), 0xccdd_eeff_7856_3412u64);
 175
 176         assert_eq!(intrinsics::size_of_val(hello) as u8, 6);
 177
 178         let chars = &['C', 'h', 'a', 'r', 's'];
 179         let chars = chars as &[char];
 180         assert_eq!(intrinsics::size_of_val(chars) as u8, 4 * 5);
 181
 182         let a: &dyn SomeTrait = &"abc\0";
 183         a.object_safe();
 184
 185         assert_eq!(intrinsics::size_of_val(a) as u8, 16);
 186         assert_eq!(intrinsics::size_of_val(&0u32) as u8, 4);
 187
 188         assert_eq!(intrinsics::min_align_of::<u16>() as u8, 2);
 189         assert_eq!(intrinsics::min_align_of_val(&a) as u8, intrinsics::min_align_of::<&str>() as u8);
 190
 191         assert!(!intrinsics::needs_drop::<u8>());
 192         assert!(!intrinsics::needs_drop::<[u8]>());
 193         assert!(intrinsics::needs_drop::<NoisyDrop>());
 194         assert!(intrinsics::needs_drop::<NoisyDropUnsized>());
 195
 196         Unique {
 197             pointer: 0 as *const &str,
 198             _marker: PhantomData,
 199         } as Unique<dyn SomeTrait>;
 200
 201         struct MyDst<T: ?Sized>(T);
 202
 203         intrinsics::size_of_val(&MyDst([0u8; 4]) as &MyDst<[u8]>);
 204
 205         struct Foo {
 206             x: u8,
 207             y: !,
 208         }
 209
 210         unsafe fn uninitialized<T>() -> T {
 211             MaybeUninit { uninit: () }.value.value
 212         }
 213
 214         zeroed::<(u8, u8)>();
 215         #[allow(unreachable_code)]
 216         {
 217             if false {
 218                 zeroed::<!>();
 219                 zeroed::<Foo>();
 220                 uninitialized::<Foo>();
 221             }
 222         }
 223     }
 224
 225     let _ = box NoisyDrop {
 226         text: "Boxed outer got dropped!\0",
 227         inner: NoisyDropInner,
 228     } as Box<dyn SomeTrait>;
 229
 230     const FUNC_REF: Option<fn()> = Some(main);
 231     match FUNC_REF {
 232         Some(_) => {},
 233         None => assert!(false),
 234     }
 235
 236     match Ordering::Less {
 237         Ordering::Less => {},
 238         _ => assert!(false),
 239     }
 240
 241     [NoisyDropInner, NoisyDropInner];
 242
 243     let x = &[0u32, 42u32] as &[u32];
 244     match x {
 245         [] => assert_eq!(0u32, 1),
 246         [_, ref y @ ..] => assert_eq!(&x[1] as *const u32 as usize, &y[0] as *const u32 as usize),
 247     }
 248
 249     assert_eq!(((|()| 42u8) as fn(()) -> u8)(()), 42);
 250
 251     extern {
 252         #[linkage = "weak"]
 253         static ABC: *const u8;
 254     }
 255
 256     {
 257         extern {
 258             #[linkage = "weak"]
 259             static ABC: *const u8;
 260         }
 261     }
 262
 263     // TODO(antoyo): to make this work, support weak linkage.
 264     //unsafe { assert_eq!(ABC as usize, 0); }
 265
 266     &mut (|| Some(0 as *const ())) as &mut dyn FnMut() -> Option<*const ()>;
 267
 268     let f = 1000.0;
 269     assert_eq!(f as u8, 255);
 270     let f2 = -1000.0;
 271     assert_eq!(f2 as i8, -128);
 272     assert_eq!(f2 as u8, 0);
 273
 274     static ANOTHER_STATIC: &u8 = &A_STATIC;
 275     assert_eq!(*ANOTHER_STATIC, 42);
 276
 277     check_niche_behavior();
 278
 279     extern "C" {
 280         type ExternType;
 281     }
 282
 283     struct ExternTypeWrapper {
 284         _a: ExternType,
 285     }
 286
 287     let nullptr = 0 as *const ();
 288     let extern_nullptr = nullptr as *const ExternTypeWrapper;
 289     extern_nullptr as *const ();
 290     let slice_ptr = &[] as *const [u8];
 291     slice_ptr as *const u8;
 292
 293     #[cfg(not(jit))]
 294     test_tls();
 295 }
 296
 297 #[repr(C)]
 298 enum c_void {
 299     _1,
 300     _2,
 301 }
 302
 303 type c_int = i32;
 304 type c_ulong = u64;
 305
 306 type pthread_t = c_ulong;
 307
 308 #[repr(C)]
 309 struct pthread_attr_t {
 310     __size: [u64; 7],
 311 }
 312
 313 #[link(name = "pthread")]
 314 extern "C" {
 315     fn pthread_attr_init(attr: *mut pthread_attr_t) -> c_int;
 316
 317     fn pthread_create(
 318         native: *mut pthread_t,
 319         attr: *const pthread_attr_t,
 320         f: extern "C" fn(_: *mut c_void) -> *mut c_void,
 321         value: *mut c_void
 322     ) -> c_int;
 323
 324     fn pthread_join(
 325         native: pthread_t,
 326         value: *mut *mut c_void
 327     ) -> c_int;
 328 }
 329
 330 #[thread_local]
 331 #[cfg(not(jit))]
 332 static mut TLS: u8 = 42;
 333
 334 #[cfg(not(jit))]
 335 extern "C" fn mutate_tls(_: *mut c_void) -> *mut c_void {
 336     unsafe { TLS = 0; }
 337     0 as *mut c_void
 338 }
 339
 340 #[cfg(not(jit))]
 341 fn test_tls() {
 342     unsafe {
 343         let mut attr: pthread_attr_t = zeroed();
 344         let mut thread: pthread_t = 0;
 345
 346         assert_eq!(TLS, 42);
 347
 348         if pthread_attr_init(&mut attr) != 0 {
 349             assert!(false);
 350         }
 351
 352         if pthread_create(&mut thread, &attr, mutate_tls, 0 as *mut c_void) != 0 {
 353             assert!(false);
 354         }
 355
 356         let mut res = 0 as *mut c_void;
 357         pthread_join(thread, &mut res);
 358
 359         // TLS of main thread must not have been changed by the other thread.
 360         assert_eq!(TLS, 42);
 361
 362         puts("TLS works!\n\0" as *const str as *const u8);
 363     }
 364 }
 365
 366 // Copied ui/issues/issue-61696.rs
 367
 368 pub enum Infallible {}
 369
 370 // The check that the `bool` field of `V1` is encoding a "niche variant"
 371 // (i.e. not `V1`, so `V3` or `V4`) used to be mathematically incorrect,
 372 // causing valid `V1` values to be interpreted as other variants.
 373 pub enum E1 {
 374     V1 { f: bool },
 375     V2 { f: Infallible },
 376     V3,
 377     V4,
 378 }
 379
 380 // Computing the discriminant used to be done using the niche type (here `u8`,
 381 // from the `bool` field of `V1`), overflowing for variants with large enough
 382 // indices (`V3` and `V4`), causing them to be interpreted as other variants.
 383 pub enum E2<X> {
 384     V1 { f: bool },
 385
 386     /*_00*/ _01(X), _02(X), _03(X), _04(X), _05(X), _06(X), _07(X),
 387     _08(X), _09(X), _0A(X), _0B(X), _0C(X), _0D(X), _0E(X), _0F(X),
 388     _10(X), _11(X), _12(X), _13(X), _14(X), _15(X), _16(X), _17(X),
 389     _18(X), _19(X), _1A(X), _1B(X), _1C(X), _1D(X), _1E(X), _1F(X),
 390     _20(X), _21(X), _22(X), _23(X), _24(X), _25(X), _26(X), _27(X),
 391     _28(X), _29(X), _2A(X), _2B(X), _2C(X), _2D(X), _2E(X), _2F(X),
 392     _30(X), _31(X), _32(X), _33(X), _34(X), _35(X), _36(X), _37(X),
 393     _38(X), _39(X), _3A(X), _3B(X), _3C(X), _3D(X), _3E(X), _3F(X),
 394     _40(X), _41(X), _42(X), _43(X), _44(X), _45(X), _46(X), _47(X),
 395     _48(X), _49(X), _4A(X), _4B(X), _4C(X), _4D(X), _4E(X), _4F(X),
 396     _50(X), _51(X), _52(X), _53(X), _54(X), _55(X), _56(X), _57(X),
 397     _58(X), _59(X), _5A(X), _5B(X), _5C(X), _5D(X), _5E(X), _5F(X),
 398     _60(X), _61(X), _62(X), _63(X), _64(X), _65(X), _66(X), _67(X),
 399     _68(X), _69(X), _6A(X), _6B(X), _6C(X), _6D(X), _6E(X), _6F(X),
 400     _70(X), _71(X), _72(X), _73(X), _74(X), _75(X), _76(X), _77(X),
 401     _78(X), _79(X), _7A(X), _7B(X), _7C(X), _7D(X), _7E(X), _7F(X),
 402     _80(X), _81(X), _82(X), _83(X), _84(X), _85(X), _86(X), _87(X),
 403     _88(X), _89(X), _8A(X), _8B(X), _8C(X), _8D(X), _8E(X), _8F(X),
 404     _90(X), _91(X), _92(X), _93(X), _94(X), _95(X), _96(X), _97(X),
 405     _98(X), _99(X), _9A(X), _9B(X), _9C(X), _9D(X), _9E(X), _9F(X),
 406     _A0(X), _A1(X), _A2(X), _A3(X), _A4(X), _A5(X), _A6(X), _A7(X),
 407     _A8(X), _A9(X), _AA(X), _AB(X), _AC(X), _AD(X), _AE(X), _AF(X),
 408     _B0(X), _B1(X), _B2(X), _B3(X), _B4(X), _B5(X), _B6(X), _B7(X),
 409     _B8(X), _B9(X), _BA(X), _BB(X), _BC(X), _BD(X), _BE(X), _BF(X),
 410     _C0(X), _C1(X), _C2(X), _C3(X), _C4(X), _C5(X), _C6(X), _C7(X),
 411     _C8(X), _C9(X), _CA(X), _CB(X), _CC(X), _CD(X), _CE(X), _CF(X),
 412     _D0(X), _D1(X), _D2(X), _D3(X), _D4(X), _D5(X), _D6(X), _D7(X),
 413     _D8(X), _D9(X), _DA(X), _DB(X), _DC(X), _DD(X), _DE(X), _DF(X),
 414     _E0(X), _E1(X), _E2(X), _E3(X), _E4(X), _E5(X), _E6(X), _E7(X),
 415     _E8(X), _E9(X), _EA(X), _EB(X), _EC(X), _ED(X), _EE(X), _EF(X),
 416     _F0(X), _F1(X), _F2(X), _F3(X), _F4(X), _F5(X), _F6(X), _F7(X),
 417     _F8(X), _F9(X), _FA(X), _FB(X), _FC(X), _FD(X), _FE(X), _FF(X),
 418
 419     V3,
 420     V4,
 421 }
 422
 423 fn check_niche_behavior () {
 424     if let E1::V2 { .. } = (E1::V1 { f: true }) {
 425         intrinsics::abort();
 426     }
 427
 428     if let E2::V1 { .. } = E2::V3::<Infallible> {
 429         intrinsics::abort();
 430     }
 431 }