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]>

8 files changed, 600 insertions, 5 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 34c535162..975c1aef8 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -425,6 +425,17 @@ dependencies = [
 ]
 
 [[package]]
+name = "goblin"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ddd5e3132801a1ac34ac53b97acde50c4685414dd2f291b9ea52afa6f07468c8"
+dependencies = [
+ "log",
+ "plain",
+ "scroll",
+]
+
+[[package]]
 name = "heck"
 version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -587,6 +598,15 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dea0c0405123bba743ee3f91f49b1c7cfb684eef0da0a50110f758ccf24cdff0"
 
 [[package]]
+name = "libloading"
+version = "0.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2c979a19ffb457f0273965c333053f3d586bf759bf7b683fbebc37f9a9ebedc4"
+dependencies = [
+ "winapi 0.3.8",
+]
+
+[[package]]
 name = "linked-hash-map"
 version = "0.5.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -826,6 +846,12 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3ad1f1b834a05d42dae330066e9699a173b28185b3bdc3dbf14ca239585de8cc"
 
 [[package]]
+name = "plain"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b4596b6d070b27117e987119b4dac604f3c58cfb0b191112e24771b2faeac1a6"
+
+[[package]]
 name = "ppv-lite86"
 version = "0.2.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -1082,10 +1108,13 @@ version = "0.1.0"
 dependencies = [
  "cargo_metadata",
  "difference",
+ "goblin",
+ "libloading",
  "ra_mbe",
  "ra_proc_macro",
  "ra_tt",
  "serde_derive",
+ "test_utils",
 ]
 
 [[package]]
@@ -1404,6 +1433,26 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"
 
 [[package]]
+name = "scroll"
+version = "0.10.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "abb2332cb595d33f7edd5700f4cbf94892e680c7f0ae56adab58a35190b66cb1"
+dependencies = [
+ "scroll_derive",
+]
+
+[[package]]
+name = "scroll_derive"
+version = "0.10.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f8584eea9b9ff42825b46faf46a8c24d2cff13ec152fa2a50df788b87c07ee28"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
 name = "semver"
 version = "0.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
diff --git a/crates/ra_proc_macro_srv/Cargo.toml b/crates/ra_proc_macro_srv/Cargo.toml
index f08de5fc7..1e0f50339 100644
--- a/crates/ra_proc_macro_srv/Cargo.toml
+++ b/crates/ra_proc_macro_srv/Cargo.toml
@@ -12,9 +12,12 @@ doctest = false
 ra_tt = { path = "../ra_tt" }
 ra_mbe = { path = "../ra_mbe" }
 ra_proc_macro = { path = "../ra_proc_macro" }
+goblin = "0.2.1"
+libloading = "0.6.0"
+test_utils = { path = "../test_utils" }
 
 [dev-dependencies]
 cargo_metadata = "0.9.1"
 difference = "2.0.0"
 # used as proc macro test target
-serde_derive = "=1.0.104"
\ No newline at end of file
+serde_derive = "=1.0.104"
diff --git a/crates/ra_proc_macro_srv/src/dylib.rs b/crates/ra_proc_macro_srv/src/dylib.rs
new file mode 100644
index 000000000..ec63d587b
--- /dev/null
+++ b/crates/ra_proc_macro_srv/src/dylib.rs
@@ -0,0 +1,211 @@
+//! Handles dynamic library loading for proc macro
+
+use crate::{proc_macro::bridge, rustc_server::TokenStream};
+use std::path::Path;
+
+use goblin::{mach::Mach, Object};
+use libloading::Library;
+use ra_proc_macro::ProcMacroKind;
+
+use std::io::Error as IoError;
+use std::io::ErrorKind as IoErrorKind;
+
+const NEW_REGISTRAR_SYMBOL: &str = "_rustc_proc_macro_decls_";
+
+fn invalid_data_err(e: impl Into<Box<dyn std::error::Error + Send + Sync>>) -> IoError {
+    IoError::new(IoErrorKind::InvalidData, e)
+}
+
+fn get_symbols_from_lib(file: &Path) -> Result<Vec<String>, IoError> {
+    let buffer = std::fs::read(file)?;
+    let object = Object::parse(&buffer).map_err(invalid_data_err)?;
+
+    match object {
+        Object::Elf(elf) => {
+            let symbols = elf.dynstrtab.to_vec().map_err(invalid_data_err)?;
+            let names = symbols.iter().map(|s| s.to_string()).collect();
+            Ok(names)
+        }
+        Object::PE(pe) => {
+            let symbol_names =
+                pe.exports.iter().flat_map(|s| s.name).map(|n| n.to_string()).collect();
+            Ok(symbol_names)
+        }
+        Object::Mach(mach) => match mach {
+            Mach::Binary(binary) => {
+                let exports = binary.exports().map_err(invalid_data_err)?;
+                let names = exports
+                    .into_iter()
+                    .map(|s| {
+                        // In macos doc:
+                        // https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man3/dlsym.3.html
+                        // Unlike other dyld API's, the symbol name passed to dlsym() must NOT be
+                        // prepended with an underscore.
+                        if s.name.starts_with("_") {
+                            s.name[1..].to_string()
+                        } else {
+                            s.name
+                        }
+                    })
+                    .collect();
+                Ok(names)
+            }
+            Mach::Fat(_) => Ok(vec![]),
+        },
+        Object::Archive(_) | Object::Unknown(_) => Ok(vec![]),
+    }
+}
+
+fn is_derive_registrar_symbol(symbol: &str) -> bool {
+    symbol.contains(NEW_REGISTRAR_SYMBOL)
+}
+
+fn find_registrar_symbol(file: &Path) -> Result<Option<String>, IoError> {
+    let symbols = get_symbols_from_lib(file)?;
+    Ok(symbols.into_iter().find(|s| is_derive_registrar_symbol(s)))
+}
+
+/// Loads dynamic library in platform dependent manner.
+///
+/// For unix, you have to use RTLD_DEEPBIND flag to escape problems described
+/// [here](https://github.com/fedochet/rust-proc-macro-panic-inside-panic-expample)
+/// and [here](https://github.com/rust-lang/rust/issues/60593).
+///
+/// Usage of RTLD_DEEPBIND
+/// [here](https://github.com/fedochet/rust-proc-macro-panic-inside-panic-expample/issues/1)
+///
+/// It seems that on Windows that behaviour is default, so we do nothing in that case.
+#[cfg(windows)]
+fn load_library(file: &Path) -> Result<Library, libloading::Error> {
+    Library::new(file)
+}
+
+#[cfg(unix)]
+fn load_library(file: &Path) -> Result<Library, libloading::Error> {
+    use libloading::os::unix::Library as UnixLibrary;
+    use std::os::raw::c_int;
+
+    const RTLD_NOW: c_int = 0x00002;
+    const RTLD_DEEPBIND: c_int = 0x00008;
+
+    UnixLibrary::open(Some(file), RTLD_NOW | RTLD_DEEPBIND).map(|lib| lib.into())
+}
+
+struct ProcMacroLibraryLibloading {
+    // Hold the dylib to prevent it for unloadeding
+    _lib: Library,
+    exported_macros: Vec<bridge::client::ProcMacro>,
+}
+
+impl ProcMacroLibraryLibloading {
+    fn open(file: &Path) -> Result<Self, IoError> {
+        let symbol_name = find_registrar_symbol(file)?
+            .ok_or(invalid_data_err(format!("Cannot find registrar symbol in file {:?}", file)))?;
+
+        let lib = load_library(file).map_err(invalid_data_err)?;
+        let exported_macros = {
+            let macros: libloading::Symbol<&&[bridge::client::ProcMacro]> =
+                unsafe { lib.get(symbol_name.as_bytes()) }.map_err(invalid_data_err)?;
+            macros.to_vec()
+        };
+
+        Ok(ProcMacroLibraryLibloading { _lib: lib, exported_macros })
+    }
+}
+
+type ProcMacroLibraryImpl = ProcMacroLibraryLibloading;
+
+pub struct Expander {
+    libs: Vec<ProcMacroLibraryImpl>,
+}
+
+impl Expander {
+    pub fn new<P: AsRef<Path>>(lib: &P) -> Result<Expander, String> {
+        let mut libs = vec![];
+        /* Some libraries for dynamic loading require canonicalized path (even when it is
+        already absolute
+        */
+        let lib =
+            lib.as_ref().canonicalize().expect(&format!("Cannot canonicalize {:?}", lib.as_ref()));
+
+        let library = ProcMacroLibraryImpl::open(&lib).map_err(|e| e.to_string())?;
+        libs.push(library);
+
+        Ok(Expander { libs })
+    }
+
+    pub fn expand(
+        &self,
+        macro_name: &str,
+        macro_body: &ra_tt::Subtree,
+        attributes: Option<&ra_tt::Subtree>,
+    ) -> Result<ra_tt::Subtree, bridge::PanicMessage> {
+        let parsed_body = TokenStream::with_subtree(macro_body.clone());
+
+        let parsed_attributes = attributes
+            .map_or(crate::rustc_server::TokenStream::new(), |attr| {
+                TokenStream::with_subtree(attr.clone())
+            });
+
+        for lib in &self.libs {
+            for proc_macro in &lib.exported_macros {
+                match proc_macro {
+                    bridge::client::ProcMacro::CustomDerive { trait_name, client, .. }
+                        if *trait_name == macro_name =>
+                    {
+                        let res = client.run(
+                            &crate::proc_macro::bridge::server::SameThread,
+                            crate::rustc_server::Rustc::default(),
+                            parsed_body,
+                        );
+                        return res.map(|it| it.subtree);
+                    }
+                    bridge::client::ProcMacro::Bang { name, client } if *name == macro_name => {
+                        let res = client.run(
+                            &crate::proc_macro::bridge::server::SameThread,
+                            crate::rustc_server::Rustc::default(),
+                            parsed_body,
+                        );
+                        return res.map(|it| it.subtree);
+                    }
+                    bridge::client::ProcMacro::Attr { name, client } if *name == macro_name => {
+                        let res = client.run(
+                            &crate::proc_macro::bridge::server::SameThread,
+                            crate::rustc_server::Rustc::default(),
+                            parsed_attributes,
+                            parsed_body,
+                        );
+
+                        return res.map(|it| it.subtree);
+                    }
+                    _ => continue,
+                }
+            }
+        }
+
+        Err(bridge::PanicMessage::String("Nothing to expand".to_string()))
+    }
+
+    pub fn list_macros(&self) -> Result<Vec<(String, ProcMacroKind)>, bridge::PanicMessage> {
+        let mut result = vec![];
+
+        for lib in &self.libs {
+            for proc_macro in &lib.exported_macros {
+                let res = match proc_macro {
+                    bridge::client::ProcMacro::CustomDerive { trait_name, .. } => {
+                        (trait_name.to_string(), ProcMacroKind::CustomDerive)
+                    }
+                    bridge::client::ProcMacro::Bang { name, .. } => {
+                        (name.to_string(), ProcMacroKind::FuncLike)
+                    }
+                    bridge::client::ProcMacro::Attr { name, .. } => {
+                        (name.to_string(), ProcMacroKind::Attr)
+                    }
+                };
+                result.push(res);
+            }
+        }
+
+        Ok(result)
+    }
+}
diff --git a/crates/ra_proc_macro_srv/src/lib.rs b/crates/ra_proc_macro_srv/src/lib.rs
index f376df236..59716cbb3 100644
--- a/crates/ra_proc_macro_srv/src/lib.rs
+++ b/crates/ra_proc_macro_srv/src/lib.rs
@@ -17,13 +17,41 @@ mod proc_macro;
 #[doc(hidden)]
 mod rustc_server;
 
+mod dylib;
+
 use proc_macro::bridge::client::TokenStream;
 use ra_proc_macro::{ExpansionResult, ExpansionTask, ListMacrosResult, ListMacrosTask};
 
-pub fn expand_task(_task: &ExpansionTask) -> Result<ExpansionResult, String> {
-    unimplemented!()
+pub fn expand_task(task: &ExpansionTask) -> Result<ExpansionResult, String> {
+    let expander = dylib::Expander::new(&task.lib)
+        .expect(&format!("Cannot expand with provided libraries: ${:?}", &task.lib));
+
+    match expander.expand(&task.macro_name, &task.macro_body, task.attributes.as_ref()) {
+        Ok(expansion) => Ok(ExpansionResult { expansion }),
+        Err(msg) => {
+            let reason = format!(
+                "Cannot perform expansion for {}: error {:?}!",
+                &task.macro_name,
+                msg.as_str()
+            );
+            Err(reason)
+        }
+    }
 }
 
-pub fn list_macros(_task: &ListMacrosTask) -> Result<ListMacrosResult, String> {
-    unimplemented!()
+pub fn list_macros(task: &ListMacrosTask) -> Result<ListMacrosResult, String> {
+    let expander = dylib::Expander::new(&task.lib)
+        .expect(&format!("Cannot expand with provided libraries: ${:?}", &task.lib));
+
+    match expander.list_macros() {
+        Ok(macros) => Ok(ListMacrosResult { macros }),
+        Err(msg) => {
+            let reason =
+                format!("Cannot perform expansion for {:?}: error {:?}!", &task.lib, msg.as_str());
+            Err(reason)
+        }
+    }
 }
+
+#[cfg(test)]
+mod tests;
diff --git a/crates/ra_proc_macro_srv/src/rustc_server.rs b/crates/ra_proc_macro_srv/src/rustc_server.rs
index 92d1fd989..ec0d35692 100644
--- a/crates/ra_proc_macro_srv/src/rustc_server.rs
+++ b/crates/ra_proc_macro_srv/src/rustc_server.rs
@@ -34,6 +34,10 @@ impl TokenStream {
         TokenStream { subtree: Default::default() }
     }
 
+    pub fn with_subtree(subtree: tt::Subtree) -> Self {
+        TokenStream { subtree }
+    }
+
     pub fn is_empty(&self) -> bool {
         self.subtree.token_trees.is_empty()
     }
diff --git a/crates/ra_proc_macro_srv/src/tests/fixtures/test_serialize_proc_macro.txt b/crates/ra_proc_macro_srv/src/tests/fixtures/test_serialize_proc_macro.txt
new file mode 100644
index 000000000..24507d98d
--- /dev/null
+++ b/crates/ra_proc_macro_srv/src/tests/fixtures/test_serialize_proc_macro.txt
@@ -0,0 +1,188 @@
+SUBTREE $
+  PUNCH   # [alone] 4294967295
+  SUBTREE [] 4294967295
+    IDENT   allow 4294967295
+    SUBTREE () 4294967295
+      IDENT   non_upper_case_globals 4294967295
+      PUNCH   , [alone] 4294967295
+      IDENT   unused_attributes 4294967295
+      PUNCH   , [alone] 4294967295
+      IDENT   unused_qualifications 4294967295
+  IDENT   const 4294967295
+  IDENT   _IMPL_SERIALIZE_FOR_Foo 4294967295
+  PUNCH   : [alone] 4294967295
+  SUBTREE () 4294967295
+  PUNCH   = [alone] 4294967295
+  SUBTREE {} 4294967295
+    PUNCH   # [alone] 4294967295
+    SUBTREE [] 4294967295
+      IDENT   allow 4294967295
+      SUBTREE () 4294967295
+        IDENT   unknown_lints 4294967295
+    PUNCH   # [alone] 4294967295
+    SUBTREE [] 4294967295
+      IDENT   cfg_attr 4294967295
+      SUBTREE () 4294967295
+        IDENT   feature 4294967295
+        PUNCH   = [alone] 4294967295
+        SUBTREE $
+          LITERAL "cargo-clippy" 0
+        PUNCH   , [alone] 4294967295
+        IDENT   allow 4294967295
+        SUBTREE () 4294967295
+          IDENT   useless_attribute 4294967295
+    PUNCH   # [alone] 4294967295
+    SUBTREE [] 4294967295
+      IDENT   allow 4294967295
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+        IDENT   rust_2018_idioms 4294967295
+    IDENT   extern 4294967295
+    IDENT   crate 4294967295
+    IDENT   serde 4294967295
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+    PUNCH   ; [alone] 4294967295
+    PUNCH   # [alone] 4294967295
+    SUBTREE [] 4294967295
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+      SUBTREE () 4294967295
+        IDENT   unused_macros 4294967295
+    IDENT   macro_rules 4294967295
+    PUNCH   ! [alone] 4294967295
+    IDENT   try 4294967295
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+        PUNCH   $ [alone] 4294967295
+        IDENT   __expr 4294967295
+        PUNCH   : [alone] 4294967295
+        IDENT   expr 4294967295
+      PUNCH   = [joint] 4294967295
+      PUNCH   > [alone] 4294967295
+      SUBTREE {} 4294967295
+        IDENT   match 4294967295
+        PUNCH   $ [alone] 4294967295
+        IDENT   __expr 4294967295
+        SUBTREE {} 4294967295
+          IDENT   _serde 4294967295
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+          PUNCH   : [alone] 4294967295
+          IDENT   export 4294967295
+          PUNCH   : [joint] 4294967295
+          PUNCH   : [alone] 4294967295
+          IDENT   Ok 4294967295
+          SUBTREE () 4294967295
+            IDENT   __val 4294967295
+          PUNCH   = [joint] 4294967295
+          PUNCH   > [alone] 4294967295
+          IDENT   __val 4294967295
+          PUNCH   , [alone] 4294967295
+          IDENT   _serde 4294967295
+          PUNCH   : [joint] 4294967295
+          PUNCH   : [alone] 4294967295
+          IDENT   export 4294967295
+          PUNCH   : [joint] 4294967295
+          PUNCH   : [alone] 4294967295
+          IDENT   Err 4294967295
+          SUBTREE () 4294967295
+            IDENT   __err 4294967295
+          PUNCH   = [joint] 4294967295
+          PUNCH   > [alone] 4294967295
+          SUBTREE {} 4294967295
+            IDENT   return 4294967295
+            IDENT   _serde 4294967295
+            PUNCH   : [joint] 4294967295
+            PUNCH   : [alone] 4294967295
+            IDENT   export 4294967295
+            PUNCH   : [joint] 4294967295
+            PUNCH   : [alone] 4294967295
+            IDENT   Err 4294967295
+            SUBTREE () 4294967295
+              IDENT   __err 4294967295
+            PUNCH   ; [alone] 4294967295
+    PUNCH   # [alone] 4294967295
+    SUBTREE [] 4294967295
+      IDENT   automatically_derived 4294967295
+    IDENT   impl 4294967295
+    IDENT   _serde 4294967295
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+    PUNCH   : [alone] 4294967295
+    IDENT   Serialize 4294967295
+    IDENT   for 4294967295
+    IDENT   Foo 1
+    SUBTREE {} 4294967295
+      IDENT   fn 4294967295
+      IDENT   serialize 4294967295
+      PUNCH   < [alone] 4294967295
+      IDENT   __S 4294967295
+      PUNCH   > [alone] 4294967295
+      SUBTREE () 4294967295
+        PUNCH   & [alone] 4294967295
+        IDENT   self 4294967295
+        PUNCH   , [alone] 4294967295
+        IDENT   __serializer 4294967295
+        PUNCH   : [alone] 4294967295
+        IDENT   __S 4294967295
+      PUNCH   - [joint] 4294967295
+      PUNCH   > [alone] 4294967295
+      IDENT   _serde 4294967295
+      PUNCH   : [joint] 4294967295
+      PUNCH   : [alone] 4294967295
+      IDENT   export 4294967295
+      PUNCH   : [joint] 4294967295
+      PUNCH   : [alone] 4294967295
+      IDENT   Result 4294967295
+      PUNCH   < [alone] 4294967295
+      IDENT   __S 4294967295
+      PUNCH   : [joint] 4294967295
+      PUNCH   : [alone] 4294967295
+      IDENT   Ok 4294967295
+      PUNCH   , [alone] 4294967295
+      IDENT   __S 4294967295
+      PUNCH   : [joint] 4294967295
+      PUNCH   : [alone] 4294967295
+      IDENT   Error 4294967295
+      PUNCH   > [alone] 4294967295
+      IDENT   where 4294967295
+      IDENT   __S 4294967295
+      PUNCH   : [alone] 4294967295
+      IDENT   _serde 4294967295
+      PUNCH   : [joint] 4294967295
+      PUNCH   : [alone] 4294967295
+      IDENT   Serializer 4294967295
+      PUNCH   , [alone] 4294967295
+      SUBTREE {} 4294967295
+        IDENT   let 4294967295
+        IDENT   __serde_state 4294967295
+        PUNCH   = [alone] 4294967295
+        IDENT   try 4294967295
+        PUNCH   ! [alone] 4294967295
+        SUBTREE () 4294967295
+          IDENT   _serde 4294967295
+          PUNCH   : [joint] 4294967295
+          PUNCH   : [alone] 4294967295
+          IDENT   Serializer 4294967295
+          PUNCH   : [joint] 4294967295
+          PUNCH   : [alone] 4294967295
+          IDENT   serialize_struct 4294967295
+          SUBTREE () 4294967295
+            IDENT   __serializer 4294967295
+            PUNCH   , [alone] 4294967295
+            LITERAL "Foo" 4294967295
+            PUNCH   , [alone] 4294967295
+            IDENT   false 4294967295
+            IDENT   as 4294967295
+            IDENT   usize 4294967295
+        PUNCH   ; [alone] 4294967295
+        IDENT   _serde 4294967295
+        PUNCH   : [joint] 4294967295
+        PUNCH   : [alone] 4294967295
+        IDENT   ser 4294967295
+        PUNCH   : [joint] 4294967295
+        PUNCH   : [alone] 4294967295
+        IDENT   SerializeStruct 4294967295
+        PUNCH   : [joint] 4294967295
+        PUNCH   : [alone] 4294967295
+        IDENT   end 4294967295
+        SUBTREE () 4294967295
+          IDENT   __serde_state 4294967295
+  PUNCH   ; [alone] 4294967295
\ No newline at end of file
diff --git a/crates/ra_proc_macro_srv/src/tests/mod.rs b/crates/ra_proc_macro_srv/src/tests/mod.rs
new file mode 100644
index 000000000..03f79bc5d
--- /dev/null
+++ b/crates/ra_proc_macro_srv/src/tests/mod.rs
@@ -0,0 +1,47 @@
+//! proc-macro tests
+
+#[macro_use]
+mod utils;
+use test_utils::assert_eq_text;
+use utils::*;
+
+#[test]
+fn test_derive_serialize_proc_macro() {
+    assert_expand(
+        "serde_derive",
+        "Serialize",
+        "1.0.104",
+        r##"struct Foo {}"##,
+        include_str!("fixtures/test_serialize_proc_macro.txt"),
+    );
+}
+
+#[test]
+fn test_derive_serialize_proc_macro_failed() {
+    assert_expand(
+        "serde_derive",
+        "Serialize",
+        "1.0.104",
+        r##"
+    struct {}
+"##,
+        r##"
+SUBTREE $
+  IDENT   compile_error 4294967295
+  PUNCH   ! [alone] 4294967295
+  SUBTREE {} 4294967295
+    LITERAL "expected identifier" 4294967295
+"##,
+    );
+}
+
+#[test]
+fn test_derive_proc_macro_list() {
+    let res = list("serde_derive", "1.0.104").join("\n");
+
+    assert_eq_text!(
+        &res,
+        r#"Serialize [CustomDerive]
+Deserialize [CustomDerive]"#
+    );
+}
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()
+}