diff --git a/src/rt/rust_builtin.cpp b/src/rt/rust_builtin.cpp
index 3a2a8e89415..ff4975fdcd8 100644
--- a/src/rt/rust_builtin.cpp
+++ b/src/rt/rust_builtin.cpp
@@ -99,53 +99,6 @@ rand_free(rust_rng *rng) {
     free(rng);
 }
 
-
-/* Debug helpers strictly to verify ABI conformance.
- *
- * FIXME (#2665): move these into a testcase when the testsuite
- * understands how to have explicit C files included.
- */
-
-struct quad {
-    uint64_t a;
-    uint64_t b;
-    uint64_t c;
-    uint64_t d;
-};
-
-struct floats {
-    double a;
-    uint8_t b;
-    double c;
-};
-
-extern "C" quad
-debug_abi_1(quad q) {
-    quad qq = { q.c + 1,
-                q.d - 1,
-                q.a + 1,
-                q.b - 1 };
-    return qq;
-}
-
-extern "C" floats
-debug_abi_2(floats f) {
-    floats ff = { f.c + 1.0,
-                  0xff,
-                  f.a - 1.0 };
-    return ff;
-}
-
-extern "C" int
-debug_static_mut;
-
-int debug_static_mut = 3;
-
-extern "C" void
-debug_static_mut_check_four() {
-    assert(debug_static_mut == 4);
-}
-
 extern "C" CDECL char*
 #if defined(__WIN32__)
 rust_list_dir_val(WIN32_FIND_DATA* entry_ptr) {
diff --git a/src/rt/rust_test_helpers.cpp b/src/rt/rust_test_helpers.cpp
index b9be4f1e251..33fea72cca7 100644
--- a/src/rt/rust_test_helpers.cpp
+++ b/src/rt/rust_test_helpers.cpp
@@ -178,3 +178,49 @@ extern "C" CDECL intptr_t
 rust_get_test_int() {
   return 1;
 }
+
+/* Debug helpers strictly to verify ABI conformance.
+ *
+ * FIXME (#2665): move these into a testcase when the testsuite
+ * understands how to have explicit C files included.
+ */
+
+struct quad {
+    uint64_t a;
+    uint64_t b;
+    uint64_t c;
+    uint64_t d;
+};
+
+struct floats {
+    double a;
+    uint8_t b;
+    double c;
+};
+
+extern "C" quad
+rust_dbg_abi_1(quad q) {
+    quad qq = { q.c + 1,
+                q.d - 1,
+                q.a + 1,
+                q.b - 1 };
+    return qq;
+}
+
+extern "C" floats
+rust_dbg_abi_2(floats f) {
+    floats ff = { f.c + 1.0,
+                  0xff,
+                  f.a - 1.0 };
+    return ff;
+}
+
+extern "C" int
+rust_dbg_static_mut;
+
+int rust_dbg_static_mut = 3;
+
+extern "C" void
+rust_dbg_static_mut_check_four() {
+    assert(rust_dbg_static_mut == 4);
+}
diff --git a/src/rt/rustrt.def.in b/src/rt/rustrt.def.in
index 54b6dc2c602..f6c15925598 100644
--- a/src/rt/rustrt.def.in
+++ b/src/rt/rustrt.def.in
@@ -1,7 +1,7 @@
-debug_abi_1
-debug_abi_2
-debug_static_mut
-debug_static_mut_check_four
+rust_dbg_abi_1
+rust_dbg_abi_2
+rust_dbg_static_mut
+rust_dbg_static_mut_check_four
 get_time
 rust_tzset
 rust_gmtime
diff --git a/src/test/compile-fail/attrs-after-extern-mod.rs b/src/test/compile-fail/attrs-after-extern-mod.rs
index 1903786eef8..3102fb2664f 100644
--- a/src/test/compile-fail/attrs-after-extern-mod.rs
+++ b/src/test/compile-fail/attrs-after-extern-mod.rs
@@ -16,8 +16,8 @@ use std::libc;
 
 #[nolink]
 extern {
-    static mut debug_static_mut: libc::c_int;
-    pub fn debug_static_mut_check_four();
+    static mut rust_dbg_static_mut: libc::c_int;
+    pub fn rust_dbg_static_mut_check_four();
     #[cfg(stage37)] //~ ERROR expected item after attributes
 }
 
diff --git a/src/test/run-pass/static-mut-foreign.rs b/src/test/run-pass/static-mut-foreign.rs
index 429b49375e0..0d042d002a1 100644
--- a/src/test/run-pass/static-mut-foreign.rs
+++ b/src/test/run-pass/static-mut-foreign.rs
@@ -16,8 +16,8 @@ use std::libc;
 
 #[nolink]
 extern {
-    static mut debug_static_mut: libc::c_int;
-    pub fn debug_static_mut_check_four();
+    static mut rust_dbg_static_mut: libc::c_int;
+    pub fn rust_dbg_static_mut_check_four();
 }
 
 unsafe fn static_bound(_: &'static libc::c_int) {}
@@ -28,18 +28,18 @@ fn static_bound_set(a: &'static mut libc::c_int) {
 
 #[fixed_stack_segment] #[inline(never)]
 unsafe fn run() {
-    assert!(debug_static_mut == 3);
-    debug_static_mut = 4;
-    assert!(debug_static_mut == 4);
-    debug_static_mut_check_four();
-    debug_static_mut += 1;
-    assert!(debug_static_mut == 5);
-    debug_static_mut *= 3;
-    assert!(debug_static_mut == 15);
-    debug_static_mut = -3;
-    assert!(debug_static_mut == -3);
-    static_bound(&debug_static_mut);
-    static_bound_set(&mut debug_static_mut);
+    assert!(rust_dbg_static_mut == 3);
+    rust_dbg_static_mut = 4;
+    assert!(rust_dbg_static_mut == 4);
+    rust_dbg_static_mut_check_four();
+    rust_dbg_static_mut += 1;
+    assert!(rust_dbg_static_mut == 5);
+    rust_dbg_static_mut *= 3;
+    assert!(rust_dbg_static_mut == 15);
+    rust_dbg_static_mut = -3;
+    assert!(rust_dbg_static_mut == -3);
+    static_bound(&rust_dbg_static_mut);
+    static_bound_set(&mut rust_dbg_static_mut);
 }
 
 pub fn main() {
diff --git a/src/test/run-pass/struct-return.rs b/src/test/run-pass/struct-return.rs
index 1c39504ba71..3f63902eb31 100644
--- a/src/test/run-pass/struct-return.rs
+++ b/src/test/run-pass/struct-return.rs
@@ -16,8 +16,8 @@ mod rustrt {
 
     #[nolink]
     extern {
-        pub fn debug_abi_1(q: Quad) -> Quad;
-        pub fn debug_abi_2(f: Floats) -> Floats;
+        pub fn rust_dbg_abi_1(q: Quad) -> Quad;
+        pub fn rust_dbg_abi_2(f: Floats) -> Floats;
     }
 }
 
@@ -28,7 +28,7 @@ fn test1() {
                  b: 0xbbbb_bbbb_bbbb_bbbb_u64,
                  c: 0xcccc_cccc_cccc_cccc_u64,
                  d: 0xdddd_dddd_dddd_dddd_u64 };
-        let qq = rustrt::debug_abi_1(q);
+        let qq = rustrt::rust_dbg_abi_1(q);
         error!("a: %x", qq.a as uint);
         error!("b: %x", qq.b as uint);
         error!("c: %x", qq.c as uint);
@@ -48,7 +48,7 @@ fn test2() {
         let f = Floats { a: 1.234567890e-15_f64,
                  b: 0b_1010_1010_u8,
                  c: 1.0987654321e-15_f64 };
-        let ff = rustrt::debug_abi_2(f);
+        let ff = rustrt::rust_dbg_abi_2(f);
         error!("a: %f", ff.a as float);
         error!("b: %u", ff.b as uint);
         error!("c: %f", ff.c as float);