diff --git a/Lib/go/goruntime.swg b/Lib/go/goruntime.swg
index 667cc35ca..c3401b1a8 100644
--- a/Lib/go/goruntime.swg
+++ b/Lib/go/goruntime.swg
@@ -88,52 +88,7 @@ typedef struct { void* array; intgo len; intgo cap; } _goslice_;
 
 %}
 
-#ifndef SWIGGO_GCCGO
-/* Boilerplate for C/C++ code when using 6g/8g.  This code is compiled
-   with gcc.  */
-%insert(runtime) %{
-
-#define swiggo_size_assert_eq(x, y, name) typedef char name[(x-y)*(x-y)*-2+1];
-#define swiggo_size_assert(t, n) swiggo_size_assert_eq(sizeof(t), n, swiggo_sizeof_##t##_is_not_##n)
-
-swiggo_size_assert(char, 1)
-swiggo_size_assert(short, 2)
-swiggo_size_assert(int, 4)
-typedef long long swiggo_long_long;
-swiggo_size_assert(swiggo_long_long, 8)
-swiggo_size_assert(float, 4)
-swiggo_size_assert(double, 8)
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-extern void crosscall2(void (*fn)(void *, int), void *, int);
-extern char* _cgo_topofstack(void) __attribute__ ((weak));
-extern void _cgo_allocate(void *, int);
-extern void _cgo_panic(void *, int);
-#ifdef __cplusplus
-}
-#endif
-
-static char *_swig_topofstack() {
-  if (_cgo_topofstack) {
-    return _cgo_topofstack();
-  } else {
-    return 0;
-  }
-}
-
-static void _swig_gopanic(const char *p) {
-  struct {
-    const char *p;
-  } SWIGSTRUCTPACKED a;
-  a.p = p;
-  crosscall2(_cgo_panic, &a, (int) sizeof a);
-}
-
-%}
-
-#else
+#ifdef SWIGGO_GCCGO
 
 /* Boilerplate for C/C++ code when using gccgo.  */
 %insert(runtime) %{
@@ -154,12 +109,6 @@ extern void _cgo_panic(const char *);
 
 #endif
 
-%insert(runtime) %{
-
-#define SWIG_contract_assert(expr, msg) \
-  if (!(expr)) { _swig_gopanic(msg); } else
-%}
-
 #ifndef SWIGGO_GCCGO
 
 %go_import("unsafe", _ "runtime/cgo")
diff --git a/Source/Modules/go.cxx b/Source/Modules/go.cxx
index 2b5261f14..7c6c7d3ff 100644
--- a/Source/Modules/go.cxx
+++ b/Source/Modules/go.cxx
@@ -637,6 +637,37 @@ private:
     Printv(f_cgo_comment, "import \"C\"\n", NULL);
     Printv(f_cgo_comment, "\n", NULL);
 
+    bool need_panic = false;
+    if (Strstr(f_c_runtime, "SWIG_contract_assert(") != 0 || Strstr(f_c_wrappers, "SWIG_contract_assert(") != 0) {
+      Printv(f_c_begin, "\n#define SWIG_contract_assert(expr, msg) if (!(expr)) { _swig_gopanic(msg); } else\n\n", NULL);
+      need_panic = true;
+    }
+
+    if (!gccgo_flag && (need_panic || Strstr(f_c_runtime, "_swig_gopanic") != 0 || Strstr(f_c_wrappers, "_swig_gopanic") != 0)) {
+      Printv(f_go_header, "//export cgo_panic_", unique_id, "\n", NULL);
+      Printv(f_go_header, "func cgo_panic_", unique_id, "(p *byte) {\n", NULL);
+      Printv(f_go_header, "\ts := (*[1024]byte)(unsafe.Pointer(p))[:]\n", NULL);
+      Printv(f_go_header, "\tvar i int\n", NULL);
+      Printv(f_go_header, "\tvar b byte\n", NULL);
+      Printv(f_go_header, "\tfor i, b = range s {\n", NULL);
+      Printv(f_go_header, "\t\tif b == 0 {\n", NULL);
+      Printv(f_go_header, "\t\t\ti--\n", NULL);
+      Printv(f_go_header, "\t\t\tbreak\n", NULL);
+      Printv(f_go_header, "\t\t}\n", NULL);
+      Printv(f_go_header, "\t}\n", NULL);
+      Printv(f_go_header, "\tpanic(string(s[:i+1]))\n", NULL);
+      Printv(f_go_header, "}\n\n", NULL);
+
+      Printv(f_c_begin, "\nextern\n", NULL);
+      Printv(f_c_begin, "#ifdef __cplusplus\n", NULL);
+      Printv(f_c_begin, "  \"C\"\n", NULL);
+      Printv(f_c_begin, "#endif\n", NULL);
+      Printv(f_c_begin, "  void cgo_panic_", unique_id, "(const char*);\n", NULL);
+      Printv(f_c_begin, "static void _swig_gopanic(const char *p) {\n", NULL);
+      Printv(f_c_begin, "  cgo_panic_", unique_id, "(p);\n", NULL);
+      Printv(f_c_begin, "}\n\n", NULL);
+    }
+
     Dump(f_c_runtime, f_c_begin);
     Dump(f_c_wrappers, f_c_begin);
     Dump(f_c_init, f_c_begin);