unit-test symbol-names and item-paths

src/librustc_trans/trans/base.rs

@@ -85,6 +85,7 @@ use trans::machine::{llalign_of_min, llsize_of, llsize_of_real};
 use trans::meth;
 use trans::mir;
 use trans::monomorphize::{self, Instance};
+use trans::symbol_names_test;
 use trans::tvec;
 use trans::type_::Type;
 use trans::type_of;
@@ -2758,6 +2759,8 @@ pub fn trans_crate<'tcx>(tcx: &TyCtxt<'tcx>,
         }
 
         collector::print_collection_results(&ccx);
+
+        symbol_names_test::report_symbol_names(&ccx);
     }
 
     emit_link_guard_if_necessary(&shared_ccx);

src/librustc_trans/trans/mod.rs

@@ -60,6 +60,7 @@ mod meth;
 mod mir;
 mod monomorphize;
 mod collector;
+mod symbol_names_test;
 mod tvec;
 mod type_;
 mod type_of;

src/librustc_trans/trans/symbol_names_test.rs

@@ -0,0 +1,84 @@
+// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Walks the crate looking for items/impl-items/trait-items that have
+//! either a `rustc_symbol_name` or `rustc_item_path` attribute and
+//! generates an error giving, respectively, the symbol name or
+//! item-path. This is used for unit testing the code that generates
+//! paths etc in all kinds of annoying scenarios.
+
+use back::symbol_names;
+use rustc::middle::ty::TyCtxt;
+use rustc_front::hir;
+use rustc_front::intravisit::{self, Visitor};
+use syntax::ast;
+use syntax::attr::AttrMetaMethods;
+use trans::common::CrateContext;
+
+const SYMBOL_NAME: &'static str = "rustc_symbol_name";
+const ITEM_PATH: &'static str = "rustc_item_path";
+
+pub fn report_symbol_names(ccx: &CrateContext) {
+    // if the `rustc_attrs` feature is not enabled, then the
+    // attributes we are interested in cannot be present anyway, so
+    // skip the walk.
+    let tcx = ccx.tcx();
+    if !tcx.sess.features.borrow().rustc_attrs {
+        return;
+    }
+
+    let _ignore = tcx.dep_graph.in_ignore();
+    let mut visitor = SymbolNamesTest { ccx: ccx, tcx: tcx };
+    tcx.map.krate().visit_all_items(&mut visitor);
+}
+
+struct SymbolNamesTest<'a, 'tcx:'a> {
+    ccx: &'a CrateContext<'a, 'tcx>,
+    tcx: &'a TyCtxt<'tcx>,
+}
+
+impl<'a, 'tcx> SymbolNamesTest<'a, 'tcx> {
+    fn process_attrs(&mut self,
+                     node_id: ast::NodeId) {
+        let def_id = self.tcx.map.local_def_id(node_id);
+        for attr in self.tcx.get_attrs(def_id).iter() {
+            if attr.check_name(SYMBOL_NAME) {
+                // for now, just monomorphic names
+                let name = symbol_names::exported_name(self.ccx, def_id, &[]);
+                self.tcx.sess.span_err(attr.span, &format!("symbol-name({})", name));
+            } else if attr.check_name(ITEM_PATH) {
+                let path = self.tcx.item_path_str(def_id);
+                self.tcx.sess.span_err(attr.span, &format!("item-path({})", path));
+            }
+
+            // (*) The formatting of `tag({})` is chosen so that tests can elect
+            // to test the entirety of the string, if they choose, or else just
+            // some subset.
+        }
+    }
+}
+
+impl<'a, 'tcx> Visitor<'tcx> for SymbolNamesTest<'a, 'tcx> {
+    fn visit_item(&mut self, item: &'tcx hir::Item) {
+        self.process_attrs(item.id);
+        intravisit::walk_item(self, item);
+    }
+
+    fn visit_trait_item(&mut self, ti: &'tcx hir::TraitItem) {
+        self.process_attrs(ti.id);
+        intravisit::walk_trait_item(self, ti)
+    }
+
+    fn visit_impl_item(&mut self, ii: &'tcx hir::ImplItem) {
+        self.process_attrs(ii.id);
+        intravisit::walk_impl_item(self, ii)
+    }
+}
+

src/libsyntax/feature_gate.rs

@@ -349,6 +349,10 @@ pub const KNOWN_ATTRIBUTES: &'static [(&'static str, AttributeType, AttributeGat
                                        "the `#[rustc_if_this_changed]` attribute \
                                         is just used for rustc unit tests \
                                         and will never be stable")),
+    ("rustc_symbol_name", Whitelisted, Gated("rustc_attrs",
+                                       "internal rustc attributes will never be stable")),
+    ("rustc_item_path", Whitelisted, Gated("rustc_attrs",
+                                       "internal rustc attributes will never be stable")),
     ("rustc_move_fragments", Normal, Gated("rustc_attrs",
                                            "the `#[rustc_move_fragments]` attribute \
                                             is just used for rustc unit tests \
@@ -579,6 +583,7 @@ pub struct Features {
     pub const_indexing: bool,
     pub static_recursion: bool,
     pub default_type_parameter_fallback: bool,
+    pub rustc_attrs: bool,
     pub type_macros: bool,
     pub cfg_target_feature: bool,
     pub cfg_target_vendor: bool,
@@ -614,6 +619,7 @@ impl Features {
             const_indexing: false,
             static_recursion: false,
             default_type_parameter_fallback: false,
+            rustc_attrs: false,
             type_macros: false,
             cfg_target_feature: false,
             cfg_target_vendor: false,
@@ -1225,6 +1231,7 @@ fn check_crate_inner<F>(cm: &CodeMap, span_handler: &Handler,
         const_indexing: cx.has_feature("const_indexing"),
         static_recursion: cx.has_feature("static_recursion"),
         default_type_parameter_fallback: cx.has_feature("default_type_parameter_fallback"),
+        rustc_attrs: cx.has_feature("rustc_attrs"),
         type_macros: cx.has_feature("type_macros"),
         cfg_target_feature: cx.has_feature("cfg_target_feature"),
         cfg_target_vendor: cx.has_feature("cfg_target_vendor"),

src/test/compile-fail/symbol-names/basic.rs

@@ -0,0 +1,16 @@
+// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![feature(rustc_attrs)]
+
+#[rustc_symbol_name] //~ ERROR _ZN5basic4main
+#[rustc_item_path] //~ ERROR item-path(main)
+fn main() {
+}

src/test/compile-fail/symbol-names/impl1.rs

@@ -0,0 +1,35 @@
+// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![feature(rustc_attrs)]
+#![allow(dead_code)]
+
+mod foo {
+    pub struct Foo { x: u32 }
+
+    impl Foo {
+        #[rustc_symbol_name] //~ ERROR _ZN5impl13foo3Foo3bar
+        #[rustc_item_path] //~ ERROR item-path(foo::Foo::bar)
+        fn bar() { }
+    }
+}
+
+mod bar {
+    use foo::Foo;
+
+    impl Foo {
+        #[rustc_symbol_name] //~ ERROR _ZN5impl13bar26_$LT$impl$u20$foo..Foo$GT$3baz
+        #[rustc_item_path] //~ ERROR item-path(bar::<impl foo::Foo>::baz)
+        fn baz() { }
+    }
+}
+
+fn main() {
+}