Auto merge of #74862 - mark-i-m:mv-compiler, r=petrochenkov

Move almost all compiler crates to compiler/

This PR implements https://github.com/rust-lang/compiler-team/issues/336 and moves all `rustc_*` crates from `src` to the new `compiler` directory.

`librustc_foo` directories are renamed to `rustc_foo`.
`src` directories are introduced inside `rustc_*` directories to mirror the scheme already use for `library` crates.

1 files changed, 25 insertions, 0 deletions

diff --git a/compiler/rustc_plugin_impl/src/lib.rs b/compiler/rustc_plugin_impl/src/lib.rs
new file mode 100644
index 00000000000..1eb65dd96ba
--- /dev/null
+++ b/compiler/rustc_plugin_impl/src/lib.rs
@@ -0,0 +1,25 @@
+//! Infrastructure for compiler plugins.
+//!
+//! Plugins are a deprecated way to extend the behavior of `rustc` in various ways.
+//!
+//! See the [`plugin`
+//! feature](https://doc.rust-lang.org/nightly/unstable-book/language-features/plugin.html)
+//! of the Unstable Book for some examples.
+
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![feature(nll)]
+#![recursion_limit = "256"]
+
+use rustc_lint::LintStore;
+
+pub mod build;
+pub mod load;
+
+/// Structure used to register plugins.
+///
+/// A plugin registrar function takes an `&mut Registry` and should call
+/// methods to register its plugins.
+pub struct Registry<'a> {
+    /// The `LintStore` allows plugins to register new lints.
+    pub lint_store: &'a mut LintStore,
+}