Merge #3920

3920: Implement expand_task and list_macros in proc_macro_srv r=matklad a=edwin0cheng

This PR finish up the remain `proc_macro_srv` implementation :

1. Added dylib loading code for proc-macro crate dylib. Note that we have to add some special flags for unix loading because of a bug in old version of glibc, see https://github.com/fedochet/rust-proc-macro-panic-inside-panic-expample/issues/1 and https://github.com/rust-lang/rust/issues/60593 for details.

2. Added tests for proc-macro expansion: We use a trick here by adding `serde_derive` to dev-dependencies and calling `cargo-metadata` for searching its dylib path, and expand it in our tests. 

[EDIT]
Note that this PR **DO NOT** implement the final glue code with rust-analzyer and proc-macro-srv yet.
 

Co-authored-by: Edwin Cheng <[email protected]>

1 files changed, 65 insertions, 0 deletions

diff --git a/crates/ra_proc_macro_srv/src/tests/utils.rs b/crates/ra_proc_macro_srv/src/tests/utils.rs
new file mode 100644
index 000000000..1ee409449
--- /dev/null
+++ b/crates/ra_proc_macro_srv/src/tests/utils.rs
@@ -0,0 +1,65 @@
+//! utils used in proc-macro tests
+
+use crate::dylib;
+use crate::list_macros;
+pub use difference::Changeset as __Changeset;
+use ra_proc_macro::ListMacrosTask;
+use std::str::FromStr;
+use test_utils::assert_eq_text;
+
+mod fixtures {
+    use cargo_metadata::{parse_messages, Message};
+    use std::process::Command;
+
+    // Use current project metadata to get the proc-macro dylib path
+    pub fn dylib_path(crate_name: &str, version: &str) -> std::path::PathBuf {
+        let command = Command::new("cargo")
+            .args(&["check", "--message-format", "json"])
+            .output()
+            .unwrap()
+            .stdout;
+
+        for message in parse_messages(command.as_slice()) {
+            match message.unwrap() {
+                Message::CompilerArtifact(artifact) => {
+                    if artifact.target.kind.contains(&"proc-macro".to_string()) {
+                        let repr = format!("{} {}", crate_name, version);
+                        if artifact.package_id.repr.starts_with(&repr) {
+                            return artifact.filenames[0].clone();
+                        }
+                    }
+                }
+                _ => (), // Unknown message
+            }
+        }
+
+        panic!("No proc-macro dylib for {} found!", crate_name);
+    }
+}
+
+fn parse_string(code: &str) -> Option<crate::rustc_server::TokenStream> {
+    Some(crate::rustc_server::TokenStream::from_str(code).unwrap())
+}
+
+pub fn assert_expand(
+    crate_name: &str,
+    macro_name: &str,
+    version: &str,
+    fixture: &str,
+    expect: &str,
+) {
+    let path = fixtures::dylib_path(crate_name, version);
+    let expander = dylib::Expander::new(&path).unwrap();
+    let fixture = parse_string(fixture).unwrap();
+
+    let res = expander.expand(macro_name, &fixture.subtree, None).unwrap();
+    assert_eq_text!(&format!("{:?}", res), &expect.trim());
+}
+
+pub fn list(crate_name: &str, version: &str) -> Vec<String> {
+    let path = fixtures::dylib_path(crate_name, version);
+    let task = ListMacrosTask { lib: path };
+
+    let res = list_macros(&task).unwrap();
+    res.macros.into_iter().map(|(name, kind)| format!("{} [{:?}]", name, kind)).collect()
+}