src/librustc/macros.rs

   1 // ignore-tidy-linelength
   2
   3 macro_rules! enum_from_u32 {
   4     ($(#[$attr:meta])* pub enum $name:ident {
   5         $($variant:ident = $e:expr,)*
   6     }) => {
   7         $(#[$attr])*
   8         pub enum $name {
   9             $($variant = $e),*
  10         }
  11
  12         impl $name {
  13             pub fn from_u32(u: u32) -> Option<$name> {
  14                 $(if u == $name::$variant as u32 {
  15                     return Some($name::$variant)
  16                 })*
  17                 None
  18             }
  19         }
  20     };
  21     ($(#[$attr:meta])* pub enum $name:ident {
  22         $($variant:ident,)*
  23     }) => {
  24         $(#[$attr])*
  25         pub enum $name {
  26             $($variant,)*
  27         }
  28
  29         impl $name {
  30             pub fn from_u32(u: u32) -> Option<$name> {
  31                 $(if u == $name::$variant as u32 {
  32                     return Some($name::$variant)
  33                 })*
  34                 None
  35             }
  36         }
  37     }
  38 }
  39
  40 #[macro_export]
  41 macro_rules! bug {
  42     () => ( bug!("impossible case reached") );
  43     ($($message:tt)*) => ({
  44         $crate::util::bug::bug_fmt(file!(), line!(), format_args!($($message)*))
  45     })
  46 }
  47
  48 #[macro_export]
  49 macro_rules! span_bug {
  50     ($span:expr, $($message:tt)*) => ({
  51         $crate::util::bug::span_bug_fmt(file!(), line!(), $span, format_args!($($message)*))
  52     })
  53 }
  54
  55 #[macro_export]
  56 macro_rules! __impl_stable_hash_field {
  57     ($field:ident, $ctx:expr, $hasher:expr) => ($field.hash_stable($ctx, $hasher));
  58     ($field:ident, $ctx:expr, $hasher:expr, _) => ({ let _ = $field; });
  59     ($field:ident, $ctx:expr, $hasher:expr, $delegate:expr) => ($delegate.hash_stable($ctx, $hasher));
  60 }
  61
  62 #[macro_export]
  63 macro_rules! impl_stable_hash_for {
  64     // Enums
  65     (enum $enum_name:path {
  66         $( $variant:ident
  67            // this incorrectly allows specifying both tuple-like and struct-like fields, as in `Variant(a,b){c,d}`,
  68            // when it should be only one or the other
  69            $( ( $($field:ident $(-> $delegate:tt)?),* ) )?
  70            $( { $($named_field:ident $(-> $named_delegate:tt)?),* } )?
  71         ),* $(,)?
  72     }) => {
  73         impl_stable_hash_for!(
  74             impl<> for enum $enum_name [ $enum_name ] { $( $variant
  75                 $( ( $($field $(-> $delegate)?),* ) )?
  76                 $( { $($named_field $(-> $named_delegate)?),* } )?
  77             ),* }
  78         );
  79     };
  80     // We want to use the enum name both in the `impl ... for $enum_name` as well as for
  81     // importing all the variants. Unfortunately it seems we have to take the name
  82     // twice for this purpose
  83     (impl<$($T:ident),* $(,)?>
  84         for enum $enum_name:path
  85         [ $enum_path:path ]
  86     {
  87         $( $variant:ident
  88            // this incorrectly allows specifying both tuple-like and struct-like fields, as in `Variant(a,b){c,d}`,
  89            // when it should be only one or the other
  90            $( ( $($field:ident $(-> $delegate:tt)?),* ) )?
  91            $( { $($named_field:ident $(-> $named_delegate:tt)?),* } )?
  92         ),* $(,)?
  93     }) => {
  94         impl<$($T,)*>
  95             ::rustc_data_structures::stable_hasher::HashStable<$crate::ich::StableHashingContext<'a>>
  96             for $enum_name
  97             where $($T: ::rustc_data_structures::stable_hasher::HashStable<$crate::ich::StableHashingContext<'a>>),*
  98         {
  99             #[inline]
 100             fn hash_stable(&self,
 101                            __ctx: &mut $crate::ich::StableHashingContext<'a>,
 102                            __hasher: &mut ::rustc_data_structures::stable_hasher::StableHasher) {
 103                 use $enum_path::*;
 104                 ::std::mem::discriminant(self).hash_stable(__ctx, __hasher);
 105
 106                 match *self {
 107                     $(
 108                         $variant $( ( $(ref $field),* ) )? $( { $(ref $named_field),* } )? => {
 109                             $($( __impl_stable_hash_field!($field, __ctx, __hasher $(, $delegate)?) );*)?
 110                             $($( __impl_stable_hash_field!($named_field, __ctx, __hasher $(, $named_delegate)?) );*)?
 111                         }
 112                     )*
 113                 }
 114             }
 115         }
 116     };
 117     // Structs
 118     (struct $struct_name:path { $($field:ident $(-> $delegate:tt)?),* $(,)? }) => {
 119         impl_stable_hash_for!(
 120             impl<> for struct $struct_name { $($field $(-> $delegate)?),* }
 121         );
 122     };
 123     (impl<$($T:ident),* $(,)?> for struct $struct_name:path {
 124         $($field:ident $(-> $delegate:tt)?),* $(,)?
 125     }) => {
 126         impl<$($T,)*>
 127             ::rustc_data_structures::stable_hasher::HashStable<$crate::ich::StableHashingContext<'a>> for $struct_name
 128             where $($T: ::rustc_data_structures::stable_hasher::HashStable<$crate::ich::StableHashingContext<'a>>),*
 129         {
 130             #[inline]
 131             fn hash_stable(&self,
 132                            __ctx: &mut $crate::ich::StableHashingContext<'a>,
 133                            __hasher: &mut ::rustc_data_structures::stable_hasher::StableHasher) {
 134                 let $struct_name {
 135                     $(ref $field),*
 136                 } = *self;
 137
 138                 $( __impl_stable_hash_field!($field, __ctx, __hasher $(, $delegate)?) );*
 139             }
 140         }
 141     };
 142     // Tuple structs
 143     // We cannot use normal parentheses here, the parser won't allow it
 144     (tuple_struct $struct_name:path { $($field:ident $(-> $delegate:tt)?),*  $(,)? }) => {
 145         impl_stable_hash_for!(
 146             impl<> for tuple_struct $struct_name { $($field $(-> $delegate)?),* }
 147         );
 148     };
 149     (impl<$($T:ident),* $(,)?>
 150      for tuple_struct $struct_name:path { $($field:ident $(-> $delegate:tt)?),*  $(,)? }) => {
 151         impl<$($T,)*>
 152             ::rustc_data_structures::stable_hasher::HashStable<$crate::ich::StableHashingContext<'a>> for $struct_name
 153             where $($T: ::rustc_data_structures::stable_hasher::HashStable<$crate::ich::StableHashingContext<'a>>),*
 154         {
 155             #[inline]
 156             fn hash_stable(&self,
 157                            __ctx: &mut $crate::ich::StableHashingContext<'a>,
 158                            __hasher: &mut ::rustc_data_structures::stable_hasher::StableHasher) {
 159                 let $struct_name (
 160                     $(ref $field),*
 161                 ) = *self;
 162
 163                 $( __impl_stable_hash_field!($field, __ctx, __hasher $(, $delegate)?) );*
 164             }
 165         }
 166     };
 167 }
 168
 169 ///////////////////////////////////////////////////////////////////////////
 170 // Lift and TypeFoldable macros
 171 //
 172 // When possible, use one of these (relatively) convenient macros to write
 173 // the impls for you.
 174
 175 #[macro_export]
 176 macro_rules! CloneLiftImpls {
 177     (for <$tcx:lifetime> { $($ty:ty,)+ }) => {
 178         $(
 179             impl<$tcx> $crate::ty::Lift<$tcx> for $ty {
 180                 type Lifted = Self;
 181                 fn lift_to_tcx(&self, _: $crate::ty::TyCtxt<$tcx>) -> Option<Self> {
 182                     Some(Clone::clone(self))
 183                 }
 184             }
 185         )+
 186     };
 187
 188     ($($ty:ty,)+) => {
 189         CloneLiftImpls! {
 190             for <'tcx> {
 191                 $($ty,)+
 192             }
 193         }
 194     };
 195 }
 196
 197 /// Used for types that are `Copy` and which **do not care arena
 198 /// allocated data** (i.e., don't need to be folded).
 199 #[macro_export]
 200 macro_rules! CloneTypeFoldableImpls {
 201     (for <$tcx:lifetime> { $($ty:ty,)+ }) => {
 202         $(
 203             impl<$tcx> $crate::ty::fold::TypeFoldable<$tcx> for $ty {
 204                 fn super_fold_with<F: $crate::ty::fold::TypeFolder<$tcx>>(
 205                     &self,
 206                     _: &mut F
 207                 ) -> $ty {
 208                     Clone::clone(self)
 209                 }
 210
 211                 fn super_visit_with<F: $crate::ty::fold::TypeVisitor<$tcx>>(
 212                     &self,
 213                     _: &mut F)
 214                     -> bool
 215                 {
 216                     false
 217                 }
 218             }
 219         )+
 220     };
 221
 222     ($($ty:ty,)+) => {
 223         CloneTypeFoldableImpls! {
 224             for <'tcx> {
 225                 $($ty,)+
 226             }
 227         }
 228     };
 229 }
 230
 231 #[macro_export]
 232 macro_rules! CloneTypeFoldableAndLiftImpls {
 233     ($($t:tt)*) => {
 234         CloneTypeFoldableImpls! { $($t)* }
 235         CloneLiftImpls! { $($t)* }
 236     }
 237 }
 238
 239 #[macro_export]
 240 macro_rules! EnumTypeFoldableImpl {
 241     (impl<$($p:tt),*> TypeFoldable<$tcx:tt> for $s:path {
 242         $($variants:tt)*
 243     } $(where $($wc:tt)*)*) => {
 244         impl<$($p),*> $crate::ty::fold::TypeFoldable<$tcx> for $s
 245             $(where $($wc)*)*
 246         {
 247             fn super_fold_with<V: $crate::ty::fold::TypeFolder<$tcx>>(
 248                 &self,
 249                 folder: &mut V,
 250             ) -> Self {
 251                 EnumTypeFoldableImpl!(@FoldVariants(self, folder) input($($variants)*) output())
 252             }
 253
 254             fn super_visit_with<V: $crate::ty::fold::TypeVisitor<$tcx>>(
 255                 &self,
 256                 visitor: &mut V,
 257             ) -> bool {
 258                 EnumTypeFoldableImpl!(@VisitVariants(self, visitor) input($($variants)*) output())
 259             }
 260         }
 261     };
 262
 263     (@FoldVariants($this:expr, $folder:expr) input() output($($output:tt)*)) => {
 264         match $this {
 265             $($output)*
 266         }
 267     };
 268
 269     (@FoldVariants($this:expr, $folder:expr)
 270      input( ($variant:path) ( $($variant_arg:ident),* ) , $($input:tt)*)
 271      output( $($output:tt)*) ) => {
 272         EnumTypeFoldableImpl!(
 273             @FoldVariants($this, $folder)
 274                 input($($input)*)
 275                 output(
 276                     $variant ( $($variant_arg),* ) => {
 277                         $variant (
 278                             $($crate::ty::fold::TypeFoldable::fold_with($variant_arg, $folder)),*
 279                         )
 280                     }
 281                     $($output)*
 282                 )
 283         )
 284     };
 285
 286     (@FoldVariants($this:expr, $folder:expr)
 287      input( ($variant:path) { $($variant_arg:ident),* $(,)? } , $($input:tt)*)
 288      output( $($output:tt)*) ) => {
 289         EnumTypeFoldableImpl!(
 290             @FoldVariants($this, $folder)
 291                 input($($input)*)
 292                 output(
 293                     $variant { $($variant_arg),* } => {
 294                         $variant {
 295                             $($variant_arg: $crate::ty::fold::TypeFoldable::fold_with(
 296                                 $variant_arg, $folder
 297                             )),* }
 298                     }
 299                     $($output)*
 300                 )
 301         )
 302     };
 303
 304     (@FoldVariants($this:expr, $folder:expr)
 305      input( ($variant:path), $($input:tt)*)
 306      output( $($output:tt)*) ) => {
 307         EnumTypeFoldableImpl!(
 308             @FoldVariants($this, $folder)
 309                 input($($input)*)
 310                 output(
 311                     $variant => { $variant }
 312                     $($output)*
 313                 )
 314         )
 315     };
 316
 317     (@VisitVariants($this:expr, $visitor:expr) input() output($($output:tt)*)) => {
 318         match $this {
 319             $($output)*
 320         }
 321     };
 322
 323     (@VisitVariants($this:expr, $visitor:expr)
 324      input( ($variant:path) ( $($variant_arg:ident),* ) , $($input:tt)*)
 325      output( $($output:tt)*) ) => {
 326         EnumTypeFoldableImpl!(
 327             @VisitVariants($this, $visitor)
 328                 input($($input)*)
 329                 output(
 330                     $variant ( $($variant_arg),* ) => {
 331                         false $(|| $crate::ty::fold::TypeFoldable::visit_with(
 332                             $variant_arg, $visitor
 333                         ))*
 334                     }
 335                     $($output)*
 336                 )
 337         )
 338     };
 339
 340     (@VisitVariants($this:expr, $visitor:expr)
 341      input( ($variant:path) { $($variant_arg:ident),* $(,)? } , $($input:tt)*)
 342      output( $($output:tt)*) ) => {
 343         EnumTypeFoldableImpl!(
 344             @VisitVariants($this, $visitor)
 345                 input($($input)*)
 346                 output(
 347                     $variant { $($variant_arg),* } => {
 348                         false $(|| $crate::ty::fold::TypeFoldable::visit_with(
 349                             $variant_arg, $visitor
 350                         ))*
 351                     }
 352                     $($output)*
 353                 )
 354         )
 355     };
 356
 357     (@VisitVariants($this:expr, $visitor:expr)
 358      input( ($variant:path), $($input:tt)*)
 359      output( $($output:tt)*) ) => {
 360         EnumTypeFoldableImpl!(
 361             @VisitVariants($this, $visitor)
 362                 input($($input)*)
 363                 output(
 364                     $variant => { false }
 365                     $($output)*
 366                 )
 367         )
 368     };
 369 }