diff --git a/src/dump.c b/src/dump.c
index 9c3b19b5f1a8d..55bb6915fee07 100644
--- a/src/dump.c
+++ b/src/dump.c
@@ -1830,7 +1830,7 @@ static void jl_insert_methods(jl_array_t *list)
     }
 }
 
-extern int jl_debug_method_invalidation;
+extern jl_array_t *_jl_debug_method_invalidation JL_GLOBALLY_ROOTED;
 
 // verify that these edges intersect with the same methods as before
 static void jl_verify_edges(jl_array_t *targets, jl_array_t **pvalids)
@@ -1884,7 +1884,8 @@ static void jl_insert_backedges(jl_array_t *list, jl_array_t *targets)
     // map(enable, ((list[i] => targets[list[i + 1] .* 2]) for i in 1:2:length(list) if all(valids[list[i + 1]])))
     size_t i, l = jl_array_len(list);
     jl_array_t *valids = NULL;
-    JL_GC_PUSH1(&valids);
+    jl_value_t *loctag = NULL;
+    JL_GC_PUSH2(&valids, &loctag);
     jl_verify_edges(targets, &valids);
     for (i = 0; i < l; i += 2) {
         jl_method_instance_t *caller = (jl_method_instance_t*)jl_array_ptr_ref(list, i);
@@ -1922,9 +1923,11 @@ static void jl_insert_backedges(jl_array_t *list, jl_array_t *targets)
             }
         }
         else {
-            if (jl_debug_method_invalidation) {
-                jl_static_show(JL_STDOUT, (jl_value_t*)caller);
-                jl_uv_puts(JL_STDOUT, "<<<\n", 4);
+            if (_jl_debug_method_invalidation) {
+                jl_array_ptr_1d_push(_jl_debug_method_invalidation, (jl_value_t*)caller);
+                loctag = jl_cstr_to_string("insert_backedges");
+                jl_gc_wb(_jl_debug_method_invalidation, loctag);
+                jl_array_ptr_1d_push(_jl_debug_method_invalidation, loctag);
             }
         }
     }
diff --git a/src/gf.c b/src/gf.c
index ef4694de438b2..51fa2f00ba454 100644
--- a/src/gf.c
+++ b/src/gf.c
@@ -1485,17 +1485,33 @@ static void update_max_args(jl_methtable_t *mt, jl_value_t *type)
         mt->max_args = na;
 }
 
-JL_DLLEXPORT int jl_debug_method_invalidation = 0;
+jl_array_t *_jl_debug_method_invalidation JL_GLOBALLY_ROOTED = NULL;
+JL_DLLEXPORT jl_value_t *jl_debug_method_invalidation(int state)
+{
+    /* After calling with `state = 1`, caller is responsible for
+       holding a reference to the returned array until this is called
+       again with `state = 0`. */
+    if (state) {
+        if (_jl_debug_method_invalidation)
+            return (jl_value_t*) _jl_debug_method_invalidation;
+        _jl_debug_method_invalidation = jl_alloc_array_1d(jl_array_any_type, 0);
+        return (jl_value_t*) _jl_debug_method_invalidation;
+    }
+    _jl_debug_method_invalidation = NULL;
+    return jl_nothing;
+}
 
 // recursively invalidate cached methods that had an edge to a replaced method
 static void invalidate_method_instance(jl_method_instance_t *replaced, size_t max_world, int depth)
 {
-    if (jl_debug_method_invalidation) {
-        int d0 = depth;
-        while (d0-- > 0)
-            jl_uv_puts(JL_STDOUT, " ", 1);
-        jl_static_show(JL_STDOUT, (jl_value_t*)replaced);
-        jl_uv_puts(JL_STDOUT, "\n", 1);
+    if (_jl_debug_method_invalidation) {
+        jl_value_t *boxeddepth = NULL;
+        JL_GC_PUSH1(&boxeddepth);
+        jl_array_ptr_1d_push(_jl_debug_method_invalidation, (jl_value_t*)replaced);
+        boxeddepth = jl_box_int32(depth);
+        jl_array_ptr_1d_push(_jl_debug_method_invalidation, boxeddepth);
+        jl_gc_wb(_jl_debug_method_invalidation, boxeddepth);
+        JL_GC_POP();
     }
     if (!jl_is_method(replaced->def.method))
         return; // shouldn't happen, but better to be safe
@@ -1622,10 +1638,14 @@ static int invalidate_mt_cache(jl_typemap_entry_t *oldentry, void *closure0)
             }
         }
         if (intersects) {
-            if (jl_debug_method_invalidation) {
-                jl_uv_puts(JL_STDOUT, "-- ", 3);
-                jl_static_show(JL_STDOUT, (jl_value_t*)mi);
-                jl_uv_puts(JL_STDOUT, "\n", 1);
+            if (_jl_debug_method_invalidation) {
+                jl_value_t *loctag = NULL;
+                JL_GC_PUSH1(&loctag);
+                jl_array_ptr_1d_push(_jl_debug_method_invalidation, (jl_value_t*)mi);
+                loctag = jl_cstr_to_string("invalidate_mt_cache");
+                jl_gc_wb(_jl_debug_method_invalidation, loctag);
+                jl_array_ptr_1d_push(_jl_debug_method_invalidation, loctag);
+                JL_GC_POP();
             }
             oldentry->max_world = env->max_world;
         }
@@ -1673,12 +1693,33 @@ JL_DLLEXPORT void jl_method_table_disable(jl_methtable_t *mt, jl_method_t *metho
     jl_typemap_visitor(mt->cache, invalidate_mt_cache, (void*)&mt_cache_env);
     // Invalidate the backedges
     jl_svec_t *specializations = methodentry->func.method->specializations;
+    int invalidated = 0;
+    jl_value_t *loctag = NULL;
+    JL_GC_PUSH1(&loctag);
     size_t i, l = jl_svec_len(specializations);
     for (i = 0; i < l; i++) {
         jl_method_instance_t *mi = (jl_method_instance_t*)jl_svecref(specializations, i);
-        if (mi)
-            invalidate_backedges(mi, methodentry->max_world);
+        if (mi) {
+            invalidated = 1;
+            if (invalidate_backedges(mi, methodentry->max_world))
+                if (_jl_debug_method_invalidation) {
+                    if (!loctag) {
+                        loctag = jl_cstr_to_string("jl_method_table_disable");
+                        jl_gc_wb(_jl_debug_method_invalidation, loctag);
+                    }
+                    jl_array_ptr_1d_push(_jl_debug_method_invalidation, loctag);
+                }
+        }
+    }
+    if (invalidated && _jl_debug_method_invalidation) {
+        jl_array_ptr_1d_push(_jl_debug_method_invalidation, (jl_value_t*)method);
+        if (!loctag) {
+            loctag = jl_cstr_to_string("jl_method_table_disable");
+            jl_gc_wb(_jl_debug_method_invalidation, loctag);
+        }
+        jl_array_ptr_1d_push(_jl_debug_method_invalidation, loctag);
     }
+    JL_GC_POP();
     JL_UNLOCK(&mt->writelock);
 }
 
@@ -1693,7 +1734,8 @@ JL_DLLEXPORT void jl_method_table_insert(jl_methtable_t *mt, jl_method_t *method
         method->primary_world = ++jl_world_counter;
     size_t max_world = method->primary_world - 1;
     int invalidated = 0;
-    JL_GC_PUSH1(&oldvalue);
+    jl_value_t *loctag = NULL;  // debug info for invalidation
+    JL_GC_PUSH2(&oldvalue, &loctag);
     JL_LOCK(&mt->writelock);
     // first delete the existing entry (we'll disable it later)
     struct jl_typemap_assoc search = {(jl_value_t*)type, method->primary_world, NULL, 0, ~(size_t)0};
@@ -1722,6 +1764,8 @@ JL_DLLEXPORT void jl_method_table_insert(jl_methtable_t *mt, jl_method_t *method
                     jl_method_instance_t *backedge = (jl_method_instance_t*)backedges[i];
                     invalidate_method_instance(backedge, max_world, 0);
                     invalidated = 1;
+                    if (_jl_debug_method_invalidation)
+                        jl_array_ptr_1d_push(_jl_debug_method_invalidation, (jl_value_t*)backedgetyp);
                 }
                 else {
                     backedges[ins++] = backedges[i - 1];
@@ -1767,17 +1811,27 @@ JL_DLLEXPORT void jl_method_table_insert(jl_methtable_t *mt, jl_method_t *method
             for (i = 0; i < l; i++) {
                 jl_method_instance_t *mi = (jl_method_instance_t*)jl_svecref(specializations, i);
                 if (mi != NULL && !jl_has_empty_intersection(type, (jl_value_t*)mi->specTypes))
-                    if (invalidate_backedges(mi, max_world))
+                    if (invalidate_backedges(mi, max_world)) {
                         invalidated = 1;
+                        if (_jl_debug_method_invalidation) {
+                            jl_array_ptr_1d_push(_jl_debug_method_invalidation, (jl_value_t*)mi);
+                            if (!loctag) {
+                                loctag = jl_cstr_to_string("jl_method_table_insert");
+                                jl_gc_wb(_jl_debug_method_invalidation, loctag);
+                            }
+                            jl_array_ptr_1d_push(_jl_debug_method_invalidation, loctag);
+                        }
+                    }
             }
         }
     }
-    if (invalidated && jl_debug_method_invalidation) {
-        jl_uv_puts(JL_STDOUT, ">> ", 3);
-        jl_static_show(JL_STDOUT, (jl_value_t*)method);
-        jl_uv_puts(JL_STDOUT, " ", 1);
-        jl_static_show(JL_STDOUT, (jl_value_t*)type);
-        jl_uv_puts(JL_STDOUT, "\n", 1);
+    if (invalidated && _jl_debug_method_invalidation) {
+        jl_array_ptr_1d_push(_jl_debug_method_invalidation, (jl_value_t*)method);
+        if (!loctag) {
+            loctag = jl_cstr_to_string("jl_method_table_insert");
+            jl_gc_wb(_jl_debug_method_invalidation, loctag);
+        }
+        jl_array_ptr_1d_push(_jl_debug_method_invalidation, loctag);
     }
     update_max_args(mt, type);
     JL_UNLOCK(&mt->writelock);