rustc_plugin: Remove support for plugin arguments

Author: petrochenkov

src/doc/unstable-book/src/language-features/plugin.md

@@ -21,10 +21,6 @@ the crate attribute `#![plugin(...)]`.  See the
 `rustc_driver::plugin` documentation for more about the
 mechanics of defining and loading a plugin.
 
-If present, arguments passed as `#![plugin(foo(... args ...))]` are not
-interpreted by rustc itself.  They are provided to the plugin through the
-`Registry`'s `args` method.
-
 In the vast majority of cases, a plugin should *only* be used through
 `#![plugin]` and not through an `extern crate` item.  Linking a plugin would
 pull in all of libsyntax and librustc as dependencies of your crate.  This is

src/librustc_feature/builtin_attrs.rs

@@ -283,7 +283,7 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
         )
     ),
     (
-        sym::plugin, CrateLevel, template!(List: "name|name(args)"),
+        sym::plugin, CrateLevel, template!(List: "name"),
         Gated(
             Stability::Deprecated(
                 "https://github.com/rust-lang/rust/pull/64675",

src/librustc_interface/passes.rs

@@ -229,8 +229,7 @@ pub fn register_plugins<'a>(
 
     time(sess, "plugin registration", || {
         for registrar in registrars {
-            registry.args_hidden = Some(registrar.args);
-            (registrar.fun)(&mut registry);
+            registrar(&mut registry);
         }
     });
 

src/librustc_plugin_impl/load.rs

@@ -9,27 +9,15 @@ use std::borrow::ToOwned;
 use std::env;
 use std::mem;
 use std::path::PathBuf;
-use syntax::ast;
+use syntax::ast::{Crate, Ident};
 use syntax::struct_span_err;
-use syntax::symbol::{Symbol, kw, sym};
-use syntax_pos::{Span, DUMMY_SP};
+use syntax::symbol::sym;
+use syntax_pos::Span;
 
 use rustc_error_codes::*;
 
 /// Pointer to a registrar function.
-pub type PluginRegistrarFun =
-    fn(&mut Registry<'_>);
-
-pub struct PluginRegistrar {
-    pub fun: PluginRegistrarFun,
-    pub args: Vec<ast::NestedMetaItem>,
-}
-
-struct PluginLoader<'a> {
-    sess: &'a Session,
-    metadata_loader: &'a dyn MetadataLoader,
-    plugins: Vec<PluginRegistrar>,
-}
+type PluginRegistrarFn = fn(&mut Registry<'_>);
 
 fn call_malformed_plugin_attribute(sess: &Session, span: Span) {
     struct_span_err!(sess, span, E0498, "malformed `plugin` attribute")
@@ -40,98 +28,81 @@ fn call_malformed_plugin_attribute(sess: &Session, span: Span) {
 /// Read plugin metadata and dynamically load registrar functions.
 pub fn load_plugins(sess: &Session,
                     metadata_loader: &dyn MetadataLoader,
-                    krate: &ast::Crate,
-                    addl_plugins: Option<Vec<String>>) -> Vec<PluginRegistrar> {
-    let mut loader = PluginLoader { sess, metadata_loader, plugins: Vec::new() };
-
-    // do not report any error now. since crate attributes are
-    // not touched by expansion, every use of plugin without
-    // the feature enabled will result in an error later...
-    if sess.features_untracked().plugin {
-        for attr in &krate.attrs {
-            if !attr.check_name(sym::plugin) {
-                continue;
-            }
-
-            let plugins = match attr.meta_item_list() {
-                Some(xs) => xs,
-                None => continue,
-            };
+                    krate: &Crate,
+                    addl_plugins: Option<Vec<String>>) -> Vec<PluginRegistrarFn> {
+    let mut plugins = Vec::new();
+    let mut load_plugin = |ident| load_plugin(&mut plugins, sess, metadata_loader, ident);
+
+    for attr in &krate.attrs {
+        if !attr.check_name(sym::plugin) {
+            continue;
+        }
 
-            for plugin in plugins {
-                // plugins must have a name and can't be key = value
-                let name = plugin.name_or_empty();
-                if name != kw::Invalid && !plugin.is_value_str() {
-                    let args = plugin.meta_item_list().map(ToOwned::to_owned);
-                    loader.load_plugin(plugin.span(), name, args.unwrap_or_default());
-                } else {
-                    call_malformed_plugin_attribute(sess, attr.span);
-                }
+        for plugin in attr.meta_item_list().unwrap_or_default() {
+            match plugin.ident() {
+                Some(ident) if plugin.is_word() => load_plugin(ident),
+                _ => call_malformed_plugin_attribute(sess, plugin.span()),
             }
         }
     }
 
-    if let Some(plugins) = addl_plugins {
-        for plugin in plugins {
-            loader.load_plugin(DUMMY_SP, Symbol::intern(&plugin), vec![]);
-        }
+    for plugin in addl_plugins.unwrap_or_default() {
+        load_plugin(Ident::from_str(&plugin));
     }
 
-    loader.plugins
+    plugins
 }
 
-impl<'a> PluginLoader<'a> {
-    fn load_plugin(&mut self, span: Span, name: Symbol, args: Vec<ast::NestedMetaItem>) {
-        let registrar = locator::find_plugin_registrar(self.sess, self.metadata_loader, span, name);
-
-        if let Some((lib, disambiguator)) = registrar {
-            let symbol = self.sess.generate_plugin_registrar_symbol(disambiguator);
-            let fun = self.dylink_registrar(span, lib, symbol);
-            self.plugins.push(PluginRegistrar {
-                fun,
-                args,
-            });
-        }
+fn load_plugin(plugins: &mut Vec<PluginRegistrarFn>,
+               sess: &Session,
+               metadata_loader: &dyn MetadataLoader,
+               ident: Ident) {
+    let registrar = locator::find_plugin_registrar(sess, metadata_loader, ident.span, ident.name);
+
+    if let Some((lib, disambiguator)) = registrar {
+        let symbol = sess.generate_plugin_registrar_symbol(disambiguator);
+        let fun = dylink_registrar(sess, ident.span, lib, symbol);
+        plugins.push(fun);
     }
+}
 
-    // Dynamically link a registrar function into the compiler process.
-    fn dylink_registrar(&mut self,
-                        span: Span,
-                        path: PathBuf,
-                        symbol: String) -> PluginRegistrarFun {
-        use rustc_metadata::dynamic_lib::DynamicLibrary;
-
-        // Make sure the path contains a / or the linker will search for it.
-        let path = env::current_dir().unwrap().join(&path);
-
-        let lib = match DynamicLibrary::open(Some(&path)) {
-            Ok(lib) => lib,
-            // this is fatal: there are almost certainly macros we need
-            // inside this crate, so continue would spew "macro undefined"
-            // errors
-            Err(err) => {
-                self.sess.span_fatal(span, &err)
-            }
-        };
-
-        unsafe {
-            let registrar =
-                match lib.symbol(&symbol) {
-                    Ok(registrar) => {
-                        mem::transmute::<*mut u8,PluginRegistrarFun>(registrar)
-                    }
-                    // again fatal if we can't register macros
-                    Err(err) => {
-                        self.sess.span_fatal(span, &err)
-                    }
-                };
-
-            // Intentionally leak the dynamic library. We can't ever unload it
-            // since the library can make things that will live arbitrarily long
-            // (e.g., an @-box cycle or a thread).
-            mem::forget(lib);
-
-            registrar
+// Dynamically link a registrar function into the compiler process.
+fn dylink_registrar(sess: &Session,
+                    span: Span,
+                    path: PathBuf,
+                    symbol: String) -> PluginRegistrarFn {
+    use rustc_metadata::dynamic_lib::DynamicLibrary;
+
+    // Make sure the path contains a / or the linker will search for it.
+    let path = env::current_dir().unwrap().join(&path);
+
+    let lib = match DynamicLibrary::open(Some(&path)) {
+        Ok(lib) => lib,
+        // this is fatal: there are almost certainly macros we need
+        // inside this crate, so continue would spew "macro undefined"
+        // errors
+        Err(err) => {
+            sess.span_fatal(span, &err)
         }
+    };
+
+    unsafe {
+        let registrar =
+            match lib.symbol(&symbol) {
+                Ok(registrar) => {
+                    mem::transmute::<*mut u8, PluginRegistrarFn>(registrar)
+                }
+                // again fatal if we can't register macros
+                Err(err) => {
+                    sess.span_fatal(span, &err)
+                }
+            };
+
+        // Intentionally leak the dynamic library. We can't ever unload it
+        // since the library can make things that will live arbitrarily long
+        // (e.g., an @-box cycle or a thread).
+        mem::forget(lib);
+
+        registrar
     }
 }

src/librustc_plugin_impl/registry.rs

@@ -2,7 +2,6 @@
 
 use rustc::lint::LintStore;
 use rustc::session::Session;
-use syntax::ast;
 use syntax_pos::Span;
 
 use std::borrow::ToOwned;
@@ -23,9 +22,6 @@ pub struct Registry<'a> {
     /// The `LintStore` allows plugins to register new lints.
     pub lint_store: &'a mut LintStore,
 
-    #[doc(hidden)]
-    pub args_hidden: Option<Vec<ast::NestedMetaItem>>,
-
     #[doc(hidden)]
     pub krate_span: Span,
 
@@ -39,26 +35,11 @@ impl<'a> Registry<'a> {
         Registry {
             sess,
             lint_store,
-            args_hidden: None,
             krate_span,
             llvm_passes: vec![],
         }
     }
 
-    /// Gets the plugin's arguments, if any.
-    ///
-    /// These are specified inside the `plugin` crate attribute as
-    ///
-    /// ```no_run
-    /// #![plugin(my_plugin_name(... args ...))]
-    /// ```
-    ///
-    /// Returns empty slice in case the plugin was loaded
-    /// with `--extra-plugins`
-    pub fn args(&self) -> &[ast::NestedMetaItem] {
-        self.args_hidden.as_ref().map(|v| &v[..]).unwrap_or(&[])
-    }
-
     /// Register an LLVM pass.
     ///
     /// Registration with LLVM itself is handled through static C++ objects with

src/test/ui/feature-gates/feature-gate-plugin.rs renamed to src/test/ui-fulldeps/feature-gate-plugin.rs

@@ -1,6 +1,7 @@
-// Test that `#![plugin(...)]` attribute is gated by `plugin` feature gate
+// aux-build:empty-plugin.rs
+// ignore-stage1
 
-#![plugin(foo)]
+#![plugin(empty_plugin)]
 //~^ ERROR compiler plugins are deprecated
 //~| WARN use of deprecated attribute `plugin`: compiler plugins are deprecated
 

src/test/ui/feature-gates/feature-gate-plugin.stderr renamed to src/test/ui-fulldeps/feature-gate-plugin.stderr

@@ -1,17 +1,17 @@
 error[E0658]: compiler plugins are deprecated
-  --> $DIR/feature-gate-plugin.rs:3:1
+  --> $DIR/feature-gate-plugin.rs:4:1
    |
-LL | #![plugin(foo)]
-   | ^^^^^^^^^^^^^^^
+LL | #![plugin(empty_plugin)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/29597
    = help: add `#![feature(plugin)]` to the crate attributes to enable
 
 warning: use of deprecated attribute `plugin`: compiler plugins are deprecated. See https://github.com/rust-lang/rust/pull/64675
-  --> $DIR/feature-gate-plugin.rs:3:1
+  --> $DIR/feature-gate-plugin.rs:4:1
    |
-LL | #![plugin(foo)]
-   | ^^^^^^^^^^^^^^^ help: may be removed in a future compiler version
+LL | #![plugin(empty_plugin)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^ help: may be removed in a future compiler version
    |
    = note: `#[warn(deprecated)]` on by default
 

src/test/ui-fulldeps/plugin-args-2.rs

@@ -1,8 +1,9 @@
-// check-pass
 // aux-build:empty-plugin.rs
 // ignore-stage1
 
 #![feature(plugin)]
-#![plugin(empty_plugin())] //~ WARNING compiler plugins are deprecated
+#![plugin(empty_plugin(args))]
+//~^ ERROR malformed `plugin` attribute
+//~| WARNING compiler plugins are deprecated
 
 fn main() {}

src/test/ui-fulldeps/plugin-args-2.stderr

@@ -1,8 +1,16 @@
+error[E0498]: malformed `plugin` attribute
+  --> $DIR/plugin-args-2.rs:5:11
+   |
+LL | #![plugin(empty_plugin(args))]
+   |           ^^^^^^^^^^^^^^^^^^ malformed attribute
+
 warning: use of deprecated attribute `plugin`: compiler plugins are deprecated. See https://github.com/rust-lang/rust/pull/64675
-  --> $DIR/plugin-args-2.rs:6:1
+  --> $DIR/plugin-args-2.rs:5:1
    |
-LL | #![plugin(empty_plugin())]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: may be removed in a future compiler version
+LL | #![plugin(empty_plugin(args))]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: may be removed in a future compiler version
    |
    = note: `#[warn(deprecated)]` on by default
 
+error: aborting due to previous error
+