Update generator upvar debug info

src/librustc_codegen_ssa/mir/mod.rs

@@ -586,10 +586,17 @@ fn arg_local_refs<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
                 return;
             }
 
+            let pin_did = tcx.lang_items().pin_type();
             // Or is it the closure environment?
             let (closure_layout, env_ref) = match arg.layout.ty.sty {
                 ty::RawPtr(ty::TypeAndMut { ty, .. }) |
                 ty::Ref(_, ty, _)  => (bx.layout_of(ty), true),
+                ty::Adt(def, substs) if Some(def.did) == pin_did => {
+                    match substs.type_at(0).sty {
+                        ty::Ref(_, ty, _)  => (bx.layout_of(ty), true),
+                        _ => (arg.layout, false),
+                    }
+                }
                 _ => (arg.layout, false)
             };
 

src/test/debuginfo/generators.rs

@@ -0,0 +1,36 @@
+// min-lldb-version: 310
+
+// compile-flags:-g
+
+// === GDB TESTS ===================================================================================
+
+// gdb-command:run
+// gdb-command:print a
+// gdb-check:$1 = 5
+
+// === LLDB TESTS ==================================================================================
+
+// lldb-command:run
+// lldb-command:print a
+// lldbg-check:(int) $0 = 5
+// lldbr-check:(int) a = 5
+
+#![feature(omit_gdb_pretty_printer_section, generators, generator_trait, pin)]
+#![omit_gdb_pretty_printer_section]
+
+use std::ops::Generator;
+use std::pin::Pin;
+
+fn main() {
+    let mut a = 5;
+    let mut b = || {
+        yield;
+        _zzz(); // #break
+        a = 6;
+    };
+    Pin::new(&mut b).resume();
+    Pin::new(&mut b).resume();
+    _zzz(); // #break
+}
+
+fn _zzz() {()}