Module `bridge`

Internal interface for communicating between a proc_macro client (a proc macro crate) and a proc_macro server (a compiler front-end).

Serialization (with C ABI buffers) and unique integer handles are employed to allow safely interfacing between two copies of proc_macro built (from the same source) by different compilers with potentially mismatching Rust ABIs (e.g., stage0/bin/rustc vs stage1/bin/rustc during bootstrap).

Modules

arena A minimal arena allocator inspired by rustc_arena::DroplessArena.
buffer Buffer management for same-process client<->server communication.
client Client-side types.
closure Closure type (equivalent to &mut dyn FnMut(Buffer) -> Buffer) that's repr(C).
fxhash This is a copy of the rustc_hash crate, adapted to work as a module.
handle Server-side handles and storage for per-handle data.
panic_message
rpc Serialization for client-server communication.
selfless_reify Abstraction for creating fn pointers from any callable that effectively has the equivalent of implementing Default, even if the compiler neither provides Default nor allows reifying closures (i.e. creating fn pointers) other than those with absolutely no captures.
server Server-side traits.
symbol Client-side interner used for symbols.

Structs

BridgeConfig Configuration for establishing an active connection between a server and a client. The server creates the bridge config (run_server in server.rs), then passes it to the client through the function pointer in the run field of client::Client. The client constructs a local Bridge from the config in TLS during its execution (Bridge::{enter, with} in client.rs).
DelimSpan
Diagnostic
ExpnGlobals Globals provided alongside the initial inputs for a macro expansion. Provides values such as spans which are used frequently to avoid RPC.
Group
Ident
Literal
Marked
Methods
Punct

Enums

ApiTags
LitKind
PanicMessage Simplified version of panic payloads, ignoring types other than &'static str and String.
TokenTree

Traits

Mark Helper to wrap associated types to allow trait impl dispatch. That is, normally a pair of impls for T::Foo and T::Bar can overlap, but if the impls are, instead, on types like Marked<T::Foo, Foo> and Marked<T::Bar, Bar>, they can't.

Macros

compound_traits
declare_tags
mark_compound
mark_noop
with_api Higher-order macro describing the server RPC API, allowing automatic generation of type-safe Rust APIs, both client-side and server-side.