4 files changed, 19 insertions, 5 deletions
diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 38d8136c1a1..43d6b9b9e90 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -983,7 +983,8 @@ pub struct InlineAsm {
     pub clobbers: InternedString,
     pub volatile: bool,
     pub alignstack: bool,
-    pub dialect: AsmDialect
+    pub dialect: AsmDialect,
+    pub expn_id: u32,
 }
 
 /// represents an argument in a function header
diff --git a/src/libsyntax/codemap.rs b/src/libsyntax/codemap.rs
index 9072889463c..d44de7862a3 100644
--- a/src/libsyntax/codemap.rs
+++ b/src/libsyntax/codemap.rs
@@ -224,7 +224,7 @@ pub struct ExpnInfo {
 }
 
 #[deriving(PartialEq, Eq, Clone, Show, Hash)]
-pub struct ExpnId(u32);
+pub struct ExpnId(pub u32);
 
 pub static NO_EXPANSION: ExpnId = ExpnId(-1);
 
diff --git a/src/libsyntax/ext/asm.rs b/src/libsyntax/ext/asm.rs
index 4b8c3376cad..f82fe4b13a2 100644
--- a/src/libsyntax/ext/asm.rs
+++ b/src/libsyntax/ext/asm.rs
@@ -13,6 +13,7 @@
  */
 
 use ast;
+use codemap;
 use codemap::Span;
 use ext::base;
 use ext::base::*;
@@ -198,6 +199,15 @@ pub fn expand_asm<'cx>(cx: &'cx mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
         }
     }
 
+    let codemap::ExpnId(expn_id) = cx.codemap().record_expansion(codemap::ExpnInfo {
+        call_site: sp,
+        callee: codemap::NameAndSpan {
+            name: "asm".to_string(),
+            format: codemap::MacroBang,
+            span: None,
+        },
+    });
+
     MacExpr::new(P(ast::Expr {
         id: ast::DUMMY_NODE_ID,
         node: ast::ExprInlineAsm(ast::InlineAsm {
@@ -208,7 +218,8 @@ pub fn expand_asm<'cx>(cx: &'cx mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
             clobbers: token::intern_and_get_ident(cons.as_slice()),
             volatile: volatile,
             alignstack: alignstack,
-            dialect: dialect
+            dialect: dialect,
+            expn_id: expn_id,
         }),
         span: sp
     }))
diff --git a/src/libsyntax/fold.rs b/src/libsyntax/fold.rs
index 91a339a73f7..53be7f2c20c 100644
--- a/src/libsyntax/fold.rs
+++ b/src/libsyntax/fold.rs
@@ -1279,7 +1279,8 @@ pub fn noop_fold_expr<T: Folder>(Expr {id, node, span}: Expr, folder: &mut T) ->
                 clobbers,
                 volatile,
                 alignstack,
-                dialect
+                dialect,
+                expn_id,
             }) => ExprInlineAsm(InlineAsm {
                 inputs: inputs.move_map(|(c, input)| {
                     (c, folder.fold_expr(input))
@@ -1292,7 +1293,8 @@ pub fn noop_fold_expr<T: Folder>(Expr {id, node, span}: Expr, folder: &mut T) ->
                 clobbers: clobbers,
                 volatile: volatile,
                 alignstack: alignstack,
-                dialect: dialect
+                dialect: dialect,
+                expn_id: expn_id,
             }),
             ExprMac(mac) => ExprMac(folder.fold_mac(mac)),
             ExprStruct(path, fields, maybe_expr) => {