syntax_ext: Turn `#[global_allocator]` into a regular attribute macro

2 files changed, 22 insertions, 1 deletions

diff --git a/src/libsyntax/ext/allocator.rs b/src/libsyntax/ext/allocator.rs
index f2c6bf27cee..99aeb5414c5 100644
--- a/src/libsyntax/ext/allocator.rs
+++ b/src/libsyntax/ext/allocator.rs
@@ -1,3 +1,7 @@
+use crate::{ast, attr, visit};
+use crate::symbol::{sym, Symbol};
+use syntax_pos::Span;
+
 #[derive(Clone, Copy)]
 pub enum AllocatorKind {
     Global,
@@ -51,3 +55,21 @@ pub static ALLOCATOR_METHODS: &[AllocatorMethod] = &[
         output: AllocatorTy::ResultPtr,
     },
 ];
+
+pub fn global_allocator_spans(krate: &ast::Crate) -> Vec<Span> {
+    struct Finder { name: Symbol, spans: Vec<Span> }
+    impl<'ast> visit::Visitor<'ast> for Finder {
+        fn visit_item(&mut self, item: &'ast ast::Item) {
+            if item.ident.name == self.name &&
+               attr::contains_name(&item.attrs, sym::rustc_std_internal_symbol) {
+                self.spans.push(item.span);
+            }
+            visit::walk_item(self, item)
+        }
+    }
+
+    let name = Symbol::intern(&AllocatorKind::Global.fn_name("alloc"));
+    let mut f = Finder { name, spans: Vec::new() };
+    visit::walk_crate(&mut f, krate);
+    f.spans
+}
diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs
index 43f0eaae7c9..214160f1079 100644
--- a/src/libsyntax/feature_gate.rs
+++ b/src/libsyntax/feature_gate.rs
@@ -1117,7 +1117,6 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
                                             "the `#[rustc_const_unstable]` attribute \
                                             is an internal feature",
                                             cfg_fn!(rustc_const_unstable))),
-    (sym::global_allocator, Normal, template!(Word), Ungated),
     (sym::default_lib_allocator, Whitelisted, template!(Word), Gated(Stability::Unstable,
                                             sym::allocator_internals,
                                             "the `#[default_lib_allocator]` \