6 files changed, 40 insertions, 0 deletions
diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index c6a3e8a2ded..131adfe47af 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -1585,6 +1585,15 @@ pub struct ForeignMod {
     pub items: Vec<ForeignItem>,
 }
 
+/// Global inline assembly
+///
+/// aka module-level assembly or file-scoped assembly
+#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
+pub struct GlobalAsm {
+    pub asm: Symbol,
+    pub ctxt: SyntaxContext,
+}
+
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 pub struct EnumDef {
     pub variants: Vec<Variant>,
@@ -1812,6 +1821,8 @@ pub enum ItemKind {
     ///
     /// E.g. `extern {}` or `extern "C" {}`
     ForeignMod(ForeignMod),
+    /// Module-level inline assembly (from `global_asm!()`)
+    GlobalAsm(P<GlobalAsm>),
     /// A type alias (`type` or `pub type`).
     ///
     /// E.g. `type Foo = Bar<u8>;`
@@ -1864,6 +1875,7 @@ impl ItemKind {
             ItemKind::Fn(..) => "function",
             ItemKind::Mod(..) => "module",
             ItemKind::ForeignMod(..) => "foreign module",
+            ItemKind::GlobalAsm(..) => "global asm",
             ItemKind::Ty(..) => "type alias",
             ItemKind::Enum(..) => "enum",
             ItemKind::Struct(..) => "struct",
diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index 1b3352f73ad..48bfc050223 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -1039,6 +1039,7 @@ impl<'feat> ExpansionConfig<'feat> {
     feature_tests! {
         fn enable_quotes = quote,
         fn enable_asm = asm,
+        fn enable_global_asm = global_asm,
         fn enable_log_syntax = log_syntax,
         fn enable_concat_idents = concat_idents,
         fn enable_trace_macros = trace_macros,
diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs
index 08762ccf04b..70e4f7a42b6 100644
--- a/src/libsyntax/feature_gate.rs
+++ b/src/libsyntax/feature_gate.rs
@@ -346,6 +346,9 @@ declare_features! (
 
     // Hack to document `-Z linker-flavor` in The Unstable Book
     (active, linker_flavor, "1.18.0", Some(41142)),
+
+    // Allows module-level inline assembly by way of global_asm!()
+    (active, global_asm, "1.18.0", Some(35119)),
 );
 
 declare_features! (
@@ -982,6 +985,9 @@ pub const EXPLAIN_STMT_ATTR_SYNTAX: &'static str =
 pub const EXPLAIN_ASM: &'static str =
     "inline assembly is not stable enough for use and is subject to change";
 
+pub const EXPLAIN_GLOBAL_ASM: &'static str =
+    "module-level inline assembly is experimental and subject to change";
+
 pub const EXPLAIN_LOG_SYNTAX: &'static str =
     "`log_syntax!` is not stable enough for use and is subject to change";
 
diff --git a/src/libsyntax/fold.rs b/src/libsyntax/fold.rs
index 92e25b00e0a..a6ab8e10d9f 100644
--- a/src/libsyntax/fold.rs
+++ b/src/libsyntax/fold.rs
@@ -140,6 +140,10 @@ pub trait Folder : Sized {
         noop_fold_foreign_mod(nm, self)
     }
 
+    fn fold_global_asm(&mut self, ga: P<GlobalAsm>) -> P<GlobalAsm> {
+        noop_fold_global_asm(ga, self)
+    }
+
     fn fold_variant(&mut self, v: Variant) -> Variant {
         noop_fold_variant(v, self)
     }
@@ -412,6 +416,11 @@ pub fn noop_fold_foreign_mod<T: Folder>(ForeignMod {abi, items}: ForeignMod,
     }
 }
 
+pub fn noop_fold_global_asm<T: Folder>(ga: P<GlobalAsm>,
+                                       _: &mut T) -> P<GlobalAsm> {
+    ga
+}
+
 pub fn noop_fold_variant<T: Folder>(v: Variant, fld: &mut T) -> Variant {
     Spanned {
         node: Variant_ {
@@ -867,6 +876,7 @@ pub fn noop_fold_item_kind<T: Folder>(i: ItemKind, folder: &mut T) -> ItemKind {
         }
         ItemKind::Mod(m) => ItemKind::Mod(folder.fold_mod(m)),
         ItemKind::ForeignMod(nm) => ItemKind::ForeignMod(folder.fold_foreign_mod(nm)),
+        ItemKind::GlobalAsm(ga) => ItemKind::GlobalAsm(folder.fold_global_asm(ga)),
         ItemKind::Ty(t, generics) => {
             ItemKind::Ty(folder.fold_ty(t), folder.fold_generics(generics))
         }
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index e7feff2b79f..433ba3d3693 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -1267,6 +1267,11 @@ impl<'a> State<'a> {
                 self.print_foreign_mod(nmod, &item.attrs)?;
                 self.bclose(item.span)?;
             }
+            ast::ItemKind::GlobalAsm(ref ga) => {
+                self.head(&visibility_qualified(&item.vis, "global_asm!"))?;
+                word(&mut self.s, &ga.asm.as_str())?;
+                self.end()?;
+            }
             ast::ItemKind::Ty(ref ty, ref params) => {
                 self.ibox(INDENT_UNIT)?;
                 self.ibox(0)?;
diff --git a/src/libsyntax/visit.rs b/src/libsyntax/visit.rs
index b5e9a1892ac..bae1c56db00 100644
--- a/src/libsyntax/visit.rs
+++ b/src/libsyntax/visit.rs
@@ -58,6 +58,7 @@ pub trait Visitor<'ast>: Sized {
     }
     fn visit_mod(&mut self, m: &'ast Mod, _s: Span, _n: NodeId) { walk_mod(self, m) }
     fn visit_foreign_item(&mut self, i: &'ast ForeignItem) { walk_foreign_item(self, i) }
+    fn visit_global_asm(&mut self, ga: &'ast GlobalAsm) { walk_global_asm(self, ga) }
     fn visit_item(&mut self, i: &'ast Item) { walk_item(self, i) }
     fn visit_local(&mut self, l: &'ast Local) { walk_local(self, l) }
     fn visit_block(&mut self, b: &'ast Block) { walk_block(self, b) }
@@ -253,6 +254,7 @@ pub fn walk_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a Item) {
         ItemKind::ForeignMod(ref foreign_module) => {
             walk_list!(visitor, visit_foreign_item, &foreign_module.items);
         }
+        ItemKind::GlobalAsm(ref ga) => visitor.visit_global_asm(ga),
         ItemKind::Ty(ref typ, ref type_parameters) => {
             visitor.visit_ty(typ);
             visitor.visit_generics(type_parameters)
@@ -464,6 +466,10 @@ pub fn walk_foreign_item<'a, V: Visitor<'a>>(visitor: &mut V, foreign_item: &'a
     walk_list!(visitor, visit_attribute, &foreign_item.attrs);
 }
 
+pub fn walk_global_asm<'a, V: Visitor<'a>>(_: &mut V, _: &'a GlobalAsm) {
+    // Empty!
+}
+
 pub fn walk_ty_param_bound<'a, V: Visitor<'a>>(visitor: &mut V, bound: &'a TyParamBound) {
     match *bound {
         TraitTyParamBound(ref typ, ref modifier) => {