library/proc_macro/src/bridge/mod.rs

   1 //! Internal interface for communicating between a `proc_macro` client
   2 //! (a proc macro crate) and a `proc_macro` server (a compiler front-end).
   3 //!
   4 //! Serialization (with C ABI buffers) and unique integer handles are employed
   5 //! to allow safely interfacing between two copies of `proc_macro` built
   6 //! (from the same source) by different compilers with potentially mismatching
   7 //! Rust ABIs (e.g., stage0/bin/rustc vs stage1/bin/rustc during bootstrap).
   8
   9 #![deny(unsafe_code)]
  10
  11 use crate::{Delimiter, Level, LineColumn, Spacing};
  12 use std::fmt;
  13 use std::hash::Hash;
  14 use std::marker;
  15 use std::mem;
  16 use std::ops::Bound;
  17 use std::panic;
  18 use std::sync::atomic::AtomicUsize;
  19 use std::sync::Once;
  20 use std::thread;
  21
  22 /// Higher-order macro describing the server RPC API, allowing automatic
  23 /// generation of type-safe Rust APIs, both client-side and server-side.
  24 ///
  25 /// `with_api!(MySelf, my_self, my_macro)` expands to:
  26 /// ```rust,ignore (pseudo-code)
  27 /// my_macro! {
  28 ///     // ...
  29 ///     Literal {
  30 ///         // ...
  31 ///         fn character(ch: char) -> MySelf::Literal;
  32 ///         // ...
  33 ///         fn span(my_self: &MySelf::Literal) -> MySelf::Span;
  34 ///         fn set_span(my_self: &mut MySelf::Literal, span: MySelf::Span);
  35 ///     },
  36 ///     // ...
  37 /// }
  38 /// ```
  39 ///
  40 /// The first two arguments serve to customize the arguments names
  41 /// and argument/return types, to enable several different usecases:
  42 ///
  43 /// If `my_self` is just `self`, then each `fn` signature can be used
  44 /// as-is for a method. If it's anything else (`self_` in practice),
  45 /// then the signatures don't have a special `self` argument, and
  46 /// can, therefore, have a different one introduced.
  47 ///
  48 /// If `MySelf` is just `Self`, then the types are only valid inside
  49 /// a trait or a trait impl, where the trait has associated types
  50 /// for each of the API types. If non-associated types are desired,
  51 /// a module name (`self` in practice) can be used instead of `Self`.
  52 macro_rules! with_api {
  53     ($S:ident, $self:ident, $m:ident) => {
  54         $m! {
  55             FreeFunctions {
  56                 fn drop($self: $S::FreeFunctions);
  57                 fn track_env_var(var: &str, value: Option<&str>);
  58             },
  59             TokenStream {
  60                 fn drop($self: $S::TokenStream);
  61                 fn clone($self: &$S::TokenStream) -> $S::TokenStream;
  62                 fn new() -> $S::TokenStream;
  63                 fn is_empty($self: &$S::TokenStream) -> bool;
  64                 fn from_str(src: &str) -> $S::TokenStream;
  65                 fn to_string($self: &$S::TokenStream) -> String;
  66                 fn from_token_tree(
  67                     tree: TokenTree<$S::Group, $S::Punct, $S::Ident, $S::Literal>,
  68                 ) -> $S::TokenStream;
  69                 fn into_iter($self: $S::TokenStream) -> $S::TokenStreamIter;
  70             },
  71             TokenStreamBuilder {
  72                 fn drop($self: $S::TokenStreamBuilder);
  73                 fn new() -> $S::TokenStreamBuilder;
  74                 fn push($self: &mut $S::TokenStreamBuilder, stream: $S::TokenStream);
  75                 fn build($self: $S::TokenStreamBuilder) -> $S::TokenStream;
  76             },
  77             TokenStreamIter {
  78                 fn drop($self: $S::TokenStreamIter);
  79                 fn clone($self: &$S::TokenStreamIter) -> $S::TokenStreamIter;
  80                 fn next(
  81                     $self: &mut $S::TokenStreamIter,
  82                 ) -> Option<TokenTree<$S::Group, $S::Punct, $S::Ident, $S::Literal>>;
  83             },
  84             Group {
  85                 fn drop($self: $S::Group);
  86                 fn clone($self: &$S::Group) -> $S::Group;
  87                 fn new(delimiter: Delimiter, stream: $S::TokenStream) -> $S::Group;
  88                 fn delimiter($self: &$S::Group) -> Delimiter;
  89                 fn stream($self: &$S::Group) -> $S::TokenStream;
  90                 fn span($self: &$S::Group) -> $S::Span;
  91                 fn span_open($self: &$S::Group) -> $S::Span;
  92                 fn span_close($self: &$S::Group) -> $S::Span;
  93                 fn set_span($self: &mut $S::Group, span: $S::Span);
  94             },
  95             Punct {
  96                 fn new(ch: char, spacing: Spacing) -> $S::Punct;
  97                 fn as_char($self: $S::Punct) -> char;
  98                 fn spacing($self: $S::Punct) -> Spacing;
  99                 fn span($self: $S::Punct) -> $S::Span;
 100                 fn with_span($self: $S::Punct, span: $S::Span) -> $S::Punct;
 101             },
 102             Ident {
 103                 fn new(string: &str, span: $S::Span, is_raw: bool) -> $S::Ident;
 104                 fn span($self: $S::Ident) -> $S::Span;
 105                 fn with_span($self: $S::Ident, span: $S::Span) -> $S::Ident;
 106             },
 107             Literal {
 108                 fn drop($self: $S::Literal);
 109                 fn clone($self: &$S::Literal) -> $S::Literal;
 110                 fn debug_kind($self: &$S::Literal) -> String;
 111                 fn symbol($self: &$S::Literal) -> String;
 112                 fn suffix($self: &$S::Literal) -> Option<String>;
 113                 fn integer(n: &str) -> $S::Literal;
 114                 fn typed_integer(n: &str, kind: &str) -> $S::Literal;
 115                 fn float(n: &str) -> $S::Literal;
 116                 fn f32(n: &str) -> $S::Literal;
 117                 fn f64(n: &str) -> $S::Literal;
 118                 fn string(string: &str) -> $S::Literal;
 119                 fn character(ch: char) -> $S::Literal;
 120                 fn byte_string(bytes: &[u8]) -> $S::Literal;
 121                 fn span($self: &$S::Literal) -> $S::Span;
 122                 fn set_span($self: &mut $S::Literal, span: $S::Span);
 123                 fn subspan(
 124                     $self: &$S::Literal,
 125                     start: Bound<usize>,
 126                     end: Bound<usize>,
 127                 ) -> Option<$S::Span>;
 128             },
 129             SourceFile {
 130                 fn drop($self: $S::SourceFile);
 131                 fn clone($self: &$S::SourceFile) -> $S::SourceFile;
 132                 fn eq($self: &$S::SourceFile, other: &$S::SourceFile) -> bool;
 133                 fn path($self: &$S::SourceFile) -> String;
 134                 fn is_real($self: &$S::SourceFile) -> bool;
 135             },
 136             MultiSpan {
 137                 fn drop($self: $S::MultiSpan);
 138                 fn new() -> $S::MultiSpan;
 139                 fn push($self: &mut $S::MultiSpan, span: $S::Span);
 140             },
 141             Diagnostic {
 142                 fn drop($self: $S::Diagnostic);
 143                 fn new(level: Level, msg: &str, span: $S::MultiSpan) -> $S::Diagnostic;
 144                 fn sub(
 145                     $self: &mut $S::Diagnostic,
 146                     level: Level,
 147                     msg: &str,
 148                     span: $S::MultiSpan,
 149                 );
 150                 fn emit($self: $S::Diagnostic);
 151             },
 152             Span {
 153                 fn debug($self: $S::Span) -> String;
 154                 fn def_site() -> $S::Span;
 155                 fn call_site() -> $S::Span;
 156                 fn mixed_site() -> $S::Span;
 157                 fn source_file($self: $S::Span) -> $S::SourceFile;
 158                 fn parent($self: $S::Span) -> Option<$S::Span>;
 159                 fn source($self: $S::Span) -> $S::Span;
 160                 fn start($self: $S::Span) -> LineColumn;
 161                 fn end($self: $S::Span) -> LineColumn;
 162                 fn join($self: $S::Span, other: $S::Span) -> Option<$S::Span>;
 163                 fn resolved_at($self: $S::Span, at: $S::Span) -> $S::Span;
 164                 fn source_text($self: $S::Span) -> Option<String>;
 165             },
 166         }
 167     };
 168 }
 169
 170 // FIXME(eddyb) this calls `encode` for each argument, but in reverse,
 171 // to avoid borrow conflicts from borrows started by `&mut` arguments.
 172 macro_rules! reverse_encode {
 173     ($writer:ident;) => {};
 174     ($writer:ident; $first:ident $(, $rest:ident)*) => {
 175         reverse_encode!($writer; $($rest),*);
 176         $first.encode(&mut $writer, &mut ());
 177     }
 178 }
 179
 180 // FIXME(eddyb) this calls `decode` for each argument, but in reverse,
 181 // to avoid borrow conflicts from borrows started by `&mut` arguments.
 182 macro_rules! reverse_decode {
 183     ($reader:ident, $s:ident;) => {};
 184     ($reader:ident, $s:ident; $first:ident: $first_ty:ty $(, $rest:ident: $rest_ty:ty)*) => {
 185         reverse_decode!($reader, $s; $($rest: $rest_ty),*);
 186         let $first = <$first_ty>::decode(&mut $reader, $s);
 187     }
 188 }
 189
 190 #[allow(unsafe_code)]
 191 mod buffer;
 192 #[forbid(unsafe_code)]
 193 pub mod client;
 194 #[allow(unsafe_code)]
 195 mod closure;
 196 #[forbid(unsafe_code)]
 197 mod handle;
 198 #[macro_use]
 199 #[forbid(unsafe_code)]
 200 mod rpc;
 201 #[allow(unsafe_code)]
 202 mod scoped_cell;
 203 #[forbid(unsafe_code)]
 204 pub mod server;
 205
 206 use buffer::Buffer;
 207 pub use rpc::PanicMessage;
 208 use rpc::{Decode, DecodeMut, Encode, Reader, Writer};
 209
 210 /// An active connection between a server and a client.
 211 /// The server creates the bridge (`Bridge::run_server` in `server.rs`),
 212 /// then passes it to the client through the function pointer in the `run`
 213 /// field of `client::Client`. The client holds its copy of the `Bridge`
 214 /// in TLS during its execution (`Bridge::{enter, with}` in `client.rs`).
 215 #[repr(C)]
 216 pub struct Bridge<'a> {
 217     /// Reusable buffer (only `clear`-ed, never shrunk), primarily
 218     /// used for making requests, but also for passing input to client.
 219     cached_buffer: Buffer<u8>,
 220
 221     /// Server-side function that the client uses to make requests.
 222     dispatch: closure::Closure<'a, Buffer<u8>, Buffer<u8>>,
 223
 224     /// If 'true', always invoke the default panic hook
 225     force_show_panics: bool,
 226 }
 227
 228 impl<'a> !Sync for Bridge<'a> {}
 229 impl<'a> !Send for Bridge<'a> {}
 230
 231 #[forbid(unsafe_code)]
 232 #[allow(non_camel_case_types)]
 233 mod api_tags {
 234     use super::rpc::{DecodeMut, Encode, Reader, Writer};
 235
 236     macro_rules! declare_tags {
 237         ($($name:ident {
 238             $(fn $method:ident($($arg:ident: $arg_ty:ty),* $(,)?) $(-> $ret_ty:ty)*;)*
 239         }),* $(,)?) => {
 240             $(
 241                 pub(super) enum $name {
 242                     $($method),*
 243                 }
 244                 rpc_encode_decode!(enum $name { $($method),* });
 245             )*
 246
 247
 248             pub(super) enum Method {
 249                 $($name($name)),*
 250             }
 251             rpc_encode_decode!(enum Method { $($name(m)),* });
 252         }
 253     }
 254     with_api!(self, self, declare_tags);
 255 }
 256
 257 /// Helper to wrap associated types to allow trait impl dispatch.
 258 /// That is, normally a pair of impls for `T::Foo` and `T::Bar`
 259 /// can overlap, but if the impls are, instead, on types like
 260 /// `Marked<T::Foo, Foo>` and `Marked<T::Bar, Bar>`, they can't.
 261 trait Mark {
 262     type Unmarked;
 263     fn mark(unmarked: Self::Unmarked) -> Self;
 264 }
 265
 266 /// Unwrap types wrapped by `Mark::mark` (see `Mark` for details).
 267 trait Unmark {
 268     type Unmarked;
 269     fn unmark(self) -> Self::Unmarked;
 270 }
 271
 272 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
 273 struct Marked<T, M> {
 274     value: T,
 275     _marker: marker::PhantomData<M>,
 276 }
 277
 278 impl<T, M> Mark for Marked<T, M> {
 279     type Unmarked = T;
 280     fn mark(unmarked: Self::Unmarked) -> Self {
 281         Marked { value: unmarked, _marker: marker::PhantomData }
 282     }
 283 }
 284 impl<T, M> Unmark for Marked<T, M> {
 285     type Unmarked = T;
 286     fn unmark(self) -> Self::Unmarked {
 287         self.value
 288     }
 289 }
 290 impl<T, M> Unmark for &'a Marked<T, M> {
 291     type Unmarked = &'a T;
 292     fn unmark(self) -> Self::Unmarked {
 293         &self.value
 294     }
 295 }
 296 impl<T, M> Unmark for &'a mut Marked<T, M> {
 297     type Unmarked = &'a mut T;
 298     fn unmark(self) -> Self::Unmarked {
 299         &mut self.value
 300     }
 301 }
 302
 303 impl<T: Mark> Mark for Option<T> {
 304     type Unmarked = Option<T::Unmarked>;
 305     fn mark(unmarked: Self::Unmarked) -> Self {
 306         unmarked.map(T::mark)
 307     }
 308 }
 309 impl<T: Unmark> Unmark for Option<T> {
 310     type Unmarked = Option<T::Unmarked>;
 311     fn unmark(self) -> Self::Unmarked {
 312         self.map(T::unmark)
 313     }
 314 }
 315
 316 macro_rules! mark_noop {
 317     ($($ty:ty),* $(,)?) => {
 318         $(
 319             impl Mark for $ty {
 320                 type Unmarked = Self;
 321                 fn mark(unmarked: Self::Unmarked) -> Self {
 322                     unmarked
 323                 }
 324             }
 325             impl Unmark for $ty {
 326                 type Unmarked = Self;
 327                 fn unmark(self) -> Self::Unmarked {
 328                     self
 329                 }
 330             }
 331         )*
 332     }
 333 }
 334 mark_noop! {
 335     (),
 336     bool,
 337     char,
 338     &'a [u8],
 339     &'a str,
 340     String,
 341     Delimiter,
 342     Level,
 343     LineColumn,
 344     Spacing,
 345     Bound<usize>,
 346 }
 347
 348 rpc_encode_decode!(
 349     enum Delimiter {
 350         Parenthesis,
 351         Brace,
 352         Bracket,
 353         None,
 354     }
 355 );
 356 rpc_encode_decode!(
 357     enum Level {
 358         Error,
 359         Warning,
 360         Note,
 361         Help,
 362     }
 363 );
 364 rpc_encode_decode!(struct LineColumn { line, column });
 365 rpc_encode_decode!(
 366     enum Spacing {
 367         Alone,
 368         Joint,
 369     }
 370 );
 371
 372 #[derive(Clone)]
 373 pub enum TokenTree<G, P, I, L> {
 374     Group(G),
 375     Punct(P),
 376     Ident(I),
 377     Literal(L),
 378 }
 379
 380 impl<G: Mark, P: Mark, I: Mark, L: Mark> Mark for TokenTree<G, P, I, L> {
 381     type Unmarked = TokenTree<G::Unmarked, P::Unmarked, I::Unmarked, L::Unmarked>;
 382     fn mark(unmarked: Self::Unmarked) -> Self {
 383         match unmarked {
 384             TokenTree::Group(tt) => TokenTree::Group(G::mark(tt)),
 385             TokenTree::Punct(tt) => TokenTree::Punct(P::mark(tt)),
 386             TokenTree::Ident(tt) => TokenTree::Ident(I::mark(tt)),
 387             TokenTree::Literal(tt) => TokenTree::Literal(L::mark(tt)),
 388         }
 389     }
 390 }
 391 impl<G: Unmark, P: Unmark, I: Unmark, L: Unmark> Unmark for TokenTree<G, P, I, L> {
 392     type Unmarked = TokenTree<G::Unmarked, P::Unmarked, I::Unmarked, L::Unmarked>;
 393     fn unmark(self) -> Self::Unmarked {
 394         match self {
 395             TokenTree::Group(tt) => TokenTree::Group(tt.unmark()),
 396             TokenTree::Punct(tt) => TokenTree::Punct(tt.unmark()),
 397             TokenTree::Ident(tt) => TokenTree::Ident(tt.unmark()),
 398             TokenTree::Literal(tt) => TokenTree::Literal(tt.unmark()),
 399         }
 400     }
 401 }
 402
 403 rpc_encode_decode!(
 404     enum TokenTree<G, P, I, L> {
 405         Group(tt),
 406         Punct(tt),
 407         Ident(tt),
 408         Literal(tt),
 409     }
 410 );