feat: Support the 1.64 nightly proc macro ABI

crates/proc-macro-srv/src/abis/abi_1_64/mod.rs

@@ -0,0 +1,104 @@
+//! Macro ABI for version 1.63 of rustc
+
+#[allow(dead_code)]
+#[doc(hidden)]
+mod proc_macro;
+
+#[allow(dead_code)]
+#[doc(hidden)]
+mod rustc_server;
+
+use libloading::Library;
+use proc_macro_api::ProcMacroKind;
+
+use super::PanicMessage;
+
+pub(crate) struct Abi {
+    exported_macros: Vec<proc_macro::bridge::client::ProcMacro>,
+}
+
+impl From<proc_macro::bridge::PanicMessage> for PanicMessage {
+    fn from(p: proc_macro::bridge::PanicMessage) -> Self {
+        Self { message: p.as_str().map(|s| s.to_string()) }
+    }
+}
+
+impl Abi {
+    pub unsafe fn from_lib(lib: &Library, symbol_name: String) -> Result<Abi, libloading::Error> {
+        let macros: libloading::Symbol<&&[proc_macro::bridge::client::ProcMacro]> =
+            lib.get(symbol_name.as_bytes())?;
+        Ok(Self { exported_macros: macros.to_vec() })
+    }
+
+    pub fn expand(
+        &self,
+        macro_name: &str,
+        macro_body: &tt::Subtree,
+        attributes: Option<&tt::Subtree>,
+    ) -> Result<tt::Subtree, PanicMessage> {
+        let parsed_body = rustc_server::TokenStream::with_subtree(macro_body.clone());
+
+        let parsed_attributes = attributes.map_or(rustc_server::TokenStream::new(), |attr| {
+            rustc_server::TokenStream::with_subtree(attr.clone())
+        });
+
+        for proc_macro in &self.exported_macros {
+            match proc_macro {
+                proc_macro::bridge::client::ProcMacro::CustomDerive {
+                    trait_name, client, ..
+                } if *trait_name == macro_name => {
+                    let res = client.run(
+                        &proc_macro::bridge::server::SameThread,
+                        rustc_server::Rustc::default(),
+                        parsed_body,
+                        true,
+                    );
+                    return res.map(|it| it.into_subtree()).map_err(PanicMessage::from);
+                }
+                proc_macro::bridge::client::ProcMacro::Bang { name, client }
+                    if *name == macro_name =>
+                {
+                    let res = client.run(
+                        &proc_macro::bridge::server::SameThread,
+                        rustc_server::Rustc::default(),
+                        parsed_body,
+                        true,
+                    );
+                    return res.map(|it| it.into_subtree()).map_err(PanicMessage::from);
+                }
+                proc_macro::bridge::client::ProcMacro::Attr { name, client }
+                    if *name == macro_name =>
+                {
+                    let res = client.run(
+                        &proc_macro::bridge::server::SameThread,
+                        rustc_server::Rustc::default(),
+                        parsed_attributes,
+                        parsed_body,
+                        true,
+                    );
+                    return res.map(|it| it.into_subtree()).map_err(PanicMessage::from);
+                }
+                _ => continue,
+            }
+        }
+
+        Err(proc_macro::bridge::PanicMessage::String("Nothing to expand".to_string()).into())
+    }
+
+    pub fn list_macros(&self) -> Vec<(String, ProcMacroKind)> {
+        self.exported_macros
+            .iter()
+            .map(|proc_macro| match proc_macro {
+                proc_macro::bridge::client::ProcMacro::CustomDerive { trait_name, .. } => {
+                    (trait_name.to_string(), ProcMacroKind::CustomDerive)
+                }
+                proc_macro::bridge::client::ProcMacro::Bang { name, .. } => {
+                    (name.to_string(), ProcMacroKind::FuncLike)
+                }
+                proc_macro::bridge::client::ProcMacro::Attr { name, .. } => {
+                    (name.to_string(), ProcMacroKind::Attr)
+                }
+            })
+            .collect()
+    }
+}

crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/buffer.rs

@@ -0,0 +1,156 @@
+//! Buffer management for same-process client<->server communication.
+
+use std::io::{self, Write};
+use std::mem;
+use std::ops::{Deref, DerefMut};
+use std::slice;
+
+#[repr(C)]
+pub struct Buffer {
+    data: *mut u8,
+    len: usize,
+    capacity: usize,
+    reserve: extern "C" fn(Buffer, usize) -> Buffer,
+    drop: extern "C" fn(Buffer),
+}
+
+unsafe impl Sync for Buffer {}
+unsafe impl Send for Buffer {}
+
+impl Default for Buffer {
+    #[inline]
+    fn default() -> Self {
+        Self::from(vec![])
+    }
+}
+
+impl Deref for Buffer {
+    type Target = [u8];
+    #[inline]
+    fn deref(&self) -> &[u8] {
+        unsafe { slice::from_raw_parts(self.data as *const u8, self.len) }
+    }
+}
+
+impl DerefMut for Buffer {
+    #[inline]
+    fn deref_mut(&mut self) -> &mut [u8] {
+        unsafe { slice::from_raw_parts_mut(self.data, self.len) }
+    }
+}
+
+impl Buffer {
+    #[inline]
+    pub(super) fn new() -> Self {
+        Self::default()
+    }
+
+    #[inline]
+    pub(super) fn clear(&mut self) {
+        self.len = 0;
+    }
+
+    #[inline]
+    pub(super) fn take(&mut self) -> Self {
+        mem::take(self)
+    }
+
+    // We have the array method separate from extending from a slice. This is
+    // because in the case of small arrays, codegen can be more efficient
+    // (avoiding a memmove call). With extend_from_slice, LLVM at least
+    // currently is not able to make that optimization.
+    #[inline]
+    pub(super) fn extend_from_array<const N: usize>(&mut self, xs: &[u8; N]) {
+        if xs.len() > (self.capacity - self.len) {
+            let b = self.take();
+            *self = (b.reserve)(b, xs.len());
+        }
+        unsafe {
+            xs.as_ptr().copy_to_nonoverlapping(self.data.add(self.len), xs.len());
+            self.len += xs.len();
+        }
+    }
+
+    #[inline]
+    pub(super) fn extend_from_slice(&mut self, xs: &[u8]) {
+        if xs.len() > (self.capacity - self.len) {
+            let b = self.take();
+            *self = (b.reserve)(b, xs.len());
+        }
+        unsafe {
+            xs.as_ptr().copy_to_nonoverlapping(self.data.add(self.len), xs.len());
+            self.len += xs.len();
+        }
+    }
+
+    #[inline]
+    pub(super) fn push(&mut self, v: u8) {
+        // The code here is taken from Vec::push, and we know that reserve()
+        // will panic if we're exceeding isize::MAX bytes and so there's no need
+        // to check for overflow.
+        if self.len == self.capacity {
+            let b = self.take();
+            *self = (b.reserve)(b, 1);
+        }
+        unsafe {
+            *self.data.add(self.len) = v;
+            self.len += 1;
+        }
+    }
+}
+
+impl Write for Buffer {
+    #[inline]
+    fn write(&mut self, xs: &[u8]) -> io::Result<usize> {
+        self.extend_from_slice(xs);
+        Ok(xs.len())
+    }
+
+    #[inline]
+    fn write_all(&mut self, xs: &[u8]) -> io::Result<()> {
+        self.extend_from_slice(xs);
+        Ok(())
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> {
+        Ok(())
+    }
+}
+
+impl Drop for Buffer {
+    #[inline]
+    fn drop(&mut self) {
+        let b = self.take();
+        (b.drop)(b);
+    }
+}
+
+impl From<Vec<u8>> for Buffer {
+    fn from(mut v: Vec<u8>) -> Self {
+        let (data, len, capacity) = (v.as_mut_ptr(), v.len(), v.capacity());
+        mem::forget(v);
+
+        // This utility function is nested in here because it can *only*
+        // be safely called on `Buffer`s created by *this* `proc_macro`.
+        fn to_vec(b: Buffer) -> Vec<u8> {
+            unsafe {
+                let Buffer { data, len, capacity, .. } = b;
+                mem::forget(b);
+                Vec::from_raw_parts(data, len, capacity)
+            }
+        }
+
+        extern "C" fn reserve(b: Buffer, additional: usize) -> Buffer {
+            let mut v = to_vec(b);
+            v.reserve(additional);
+            Buffer::from(v)
+        }
+
+        extern "C" fn drop(b: Buffer) {
+            mem::drop(to_vec(b));
+        }
+
+        Buffer { data, len, capacity, reserve, drop }
+    }
+}