staticdata: Memoize type_in_worklist query (#57917)

When pre-compiling `stdlib/` this cache has a 91% hit rate, so this
seems fairly profitable. It also dramatically improves some pathological
cases, a few of which have been hit in the wild (arguably due to
inference bugs)

Without this PR, this package takes exponentially long to pre-compile:
```julia
function BigType(N)
    (N == 0) && return Nothing
    T = BigType(N-1)
    return Pair{T,T}
end
foo(::Type{T}) where T = T
precompile(foo, (Type{BigType(40)},))
```

For an in-the-wild test case hit by a customer, this reduces
pre-compilation time from over an hour to just ~two and a half minutes.

Resolves #53331.

Author: topolarity

src/staticdata.c

@@ -90,6 +90,22 @@ External links:
 
 static const size_t WORLD_AGE_REVALIDATION_SENTINEL = 0x1;
 
+// This structure is used to store hash tables for the memoization
+// of queries in staticdata.c (currently only `type_in_worklist`).
+typedef struct {
+    htable_t type_in_worklist;
+} jl_query_cache;
+
+static void init_query_cache(jl_query_cache *cache)
+{
+    htable_new(&cache->type_in_worklist, 0);
+}
+
+static void destroy_query_cache(jl_query_cache *cache)
+{
+    htable_free(&cache->type_in_worklist);
+}
+
 #include "staticdata_utils.c"
 #include "precompile_utils.c"
 
@@ -512,6 +528,7 @@ typedef struct {
     jl_array_t *link_ids_gctags;
     jl_array_t *link_ids_gvars;
     jl_array_t *link_ids_external_fnvars;
+    jl_query_cache *query_cache;
     jl_ptls_t ptls;
     // Set (implemented has a hasmap of MethodInstances to themselves) of which MethodInstances have (forward) edges
     // to other MethodInstances.
@@ -658,38 +675,37 @@ static int jl_needs_serialization(jl_serializer_state *s, jl_value_t *v) JL_NOTS
     return 1;
 }
 
-
-static int caching_tag(jl_value_t *v) JL_NOTSAFEPOINT
+static int caching_tag(jl_value_t *v, jl_query_cache *query_cache) JL_NOTSAFEPOINT
 {
     if (jl_is_method_instance(v)) {
         jl_method_instance_t *mi = (jl_method_instance_t*)v;
         jl_value_t *m = mi->def.value;
         if (jl_is_method(m) && jl_object_in_image(m))
-            return 1 + type_in_worklist(mi->specTypes);
+            return 1 + type_in_worklist(mi->specTypes, query_cache);
     }
     if (jl_is_datatype(v)) {
         jl_datatype_t *dt = (jl_datatype_t*)v;
         if (jl_is_tuple_type(dt) ? !dt->isconcretetype : dt->hasfreetypevars)
             return 0; // aka !is_cacheable from jltypes.c
         if (jl_object_in_image((jl_value_t*)dt->name))
-            return 1 + type_in_worklist(v);
+            return 1 + type_in_worklist(v, query_cache);
     }
     jl_value_t *dtv = jl_typeof(v);
     if (jl_is_datatype_singleton((jl_datatype_t*)dtv)) {
-        return 1 - type_in_worklist(dtv); // these are already recached in the datatype in the image
+        return 1 - type_in_worklist(dtv, query_cache); // these are already recached in the datatype in the image
     }
     return 0;
 }
 
-static int needs_recaching(jl_value_t *v) JL_NOTSAFEPOINT
+static int needs_recaching(jl_value_t *v, jl_query_cache *query_cache) JL_NOTSAFEPOINT
 {
-    return caching_tag(v) == 2;
+    return caching_tag(v, query_cache) == 2;
 }
 
-static int needs_uniquing(jl_value_t *v) JL_NOTSAFEPOINT
+static int needs_uniquing(jl_value_t *v, jl_query_cache *query_cache) JL_NOTSAFEPOINT
 {
     assert(!jl_object_in_image(v));
-    return caching_tag(v) == 1;
+    return caching_tag(v, query_cache) == 1;
 }
 
 static void record_field_change(jl_value_t **addr, jl_value_t *newval) JL_NOTSAFEPOINT
@@ -774,7 +790,7 @@ static void jl_insert_into_serialization_queue(jl_serializer_state *s, jl_value_
         jl_datatype_t *dt = (jl_datatype_t*)v;
         // ensure all type parameters are recached
         jl_queue_for_serialization_(s, (jl_value_t*)dt->parameters, 1, 1);
-        if (jl_is_datatype_singleton(dt) && needs_uniquing(dt->instance)) {
+        if (jl_is_datatype_singleton(dt) && needs_uniquing(dt->instance, s->query_cache)) {
             assert(jl_needs_serialization(s, dt->instance)); // should be true, since we visited dt
             // do not visit dt->instance for our template object as it leads to unwanted cycles here
             // (it may get serialized from elsewhere though)
@@ -785,7 +801,7 @@ static void jl_insert_into_serialization_queue(jl_serializer_state *s, jl_value_
     if (s->incremental && jl_is_method_instance(v)) {
         jl_method_instance_t *mi = (jl_method_instance_t*)v;
         jl_value_t *def = mi->def.value;
-        if (needs_uniquing(v)) {
+        if (needs_uniquing(v, s->query_cache)) {
             // we only need 3 specific fields of this (the rest are not used)
             jl_queue_for_serialization(s, mi->def.value);
             jl_queue_for_serialization(s, mi->specTypes);
@@ -801,7 +817,7 @@ static void jl_insert_into_serialization_queue(jl_serializer_state *s, jl_value_
             record_field_change((jl_value_t**)&mi->cache, NULL);
         }
         else {
-            assert(!needs_recaching(v));
+            assert(!needs_recaching(v, s->query_cache));
         }
         // n.b. opaque closures cannot be inspected and relied upon like a
         // normal method since they can get improperly introduced by generated
@@ -947,9 +963,9 @@ static void jl_queue_for_serialization_(jl_serializer_state *s, jl_value_t *v, i
     // Items that require postorder traversal must visit their children prior to insertion into
     // the worklist/serialization_order (and also before their first use)
     if (s->incremental && !immediate) {
-        if (jl_is_datatype(t) && needs_uniquing(v))
+        if (jl_is_datatype(t) && needs_uniquing(v, s->query_cache))
             immediate = 1;
-        if (jl_is_datatype_singleton((jl_datatype_t*)t) && needs_uniquing(v))
+        if (jl_is_datatype_singleton((jl_datatype_t*)t) && needs_uniquing(v, s->query_cache))
             immediate = 1;
     }
 
@@ -1113,7 +1129,7 @@ static uintptr_t _backref_id(jl_serializer_state *s, jl_value_t *v, jl_array_t *
 
 static void record_uniquing(jl_serializer_state *s, jl_value_t *fld, uintptr_t offset) JL_NOTSAFEPOINT
 {
-    if (s->incremental && jl_needs_serialization(s, fld) && needs_uniquing(fld)) {
+    if (s->incremental && jl_needs_serialization(s, fld) && needs_uniquing(fld, s->query_cache)) {
         if (jl_is_datatype(fld) || jl_is_datatype_singleton((jl_datatype_t*)jl_typeof(fld)))
             arraylist_push(&s->uniquing_types, (void*)(uintptr_t)offset);
         else if (jl_is_method_instance(fld))
@@ -1297,7 +1313,7 @@ static void jl_write_values(jl_serializer_state *s) JL_GC_DISABLED
         // write header
         if (object_id_expected)
             write_uint(f, jl_object_id(v));
-        if (s->incremental && jl_needs_serialization(s, (jl_value_t*)t) && needs_uniquing((jl_value_t*)t))
+        if (s->incremental && jl_needs_serialization(s, (jl_value_t*)t) && needs_uniquing((jl_value_t*)t, s->query_cache))
             arraylist_push(&s->uniquing_types, (void*)(uintptr_t)(ios_pos(f)|1));
         if (f == s->const_data)
             write_uint(s->const_data, ((uintptr_t)t->smalltag << 4) | GC_OLD_MARKED | GC_IN_IMAGE);
@@ -1308,7 +1324,7 @@ static void jl_write_values(jl_serializer_state *s) JL_GC_DISABLED
         layout_table.items[item] = (void*)(reloc_offset | (f == s->const_data)); // store the inverse mapping of `serialization_order` (`id` => object-as-streampos)
 
         if (s->incremental) {
-            if (needs_uniquing(v)) {
+            if (needs_uniquing(v, s->query_cache)) {
                 if (jl_is_method_instance(v)) {
                     assert(f == s->s);
                     jl_method_instance_t *mi = (jl_method_instance_t*)v;
@@ -1329,7 +1345,7 @@ static void jl_write_values(jl_serializer_state *s) JL_GC_DISABLED
                     assert(jl_is_datatype_singleton(t) && "unreachable");
                 }
             }
-            else if (needs_recaching(v)) {
+            else if (needs_recaching(v, s->query_cache)) {
                 arraylist_push(jl_is_datatype(v) ? &s->fixup_types : &s->fixup_objs, (void*)reloc_offset);
             }
             else if (jl_typetagis(v, jl_binding_type)) {
@@ -1731,7 +1747,7 @@ static void jl_write_values(jl_serializer_state *s) JL_GC_DISABLED
                     }
                 }
                 void *superidx = ptrhash_get(&serialization_order, dt->super);
-                if (s->incremental && superidx != HT_NOTFOUND && (char*)superidx - 1 - (char*)HT_NOTFOUND > item && needs_uniquing((jl_value_t*)dt->super))
+                if (s->incremental && superidx != HT_NOTFOUND && (char*)superidx - 1 - (char*)HT_NOTFOUND > item && needs_uniquing((jl_value_t*)dt->super, s->query_cache))
                     arraylist_push(&s->uniquing_super, dt->super);
             }
             else if (jl_is_typename(v)) {
@@ -2540,7 +2556,8 @@ JL_DLLEXPORT jl_value_t *jl_as_global_root(jl_value_t *val, int insert)
 
 static void jl_prepare_serialization_data(jl_array_t *mod_array, jl_array_t *newly_inferred, uint64_t worklist_key,
                            /* outputs */  jl_array_t **extext_methods, jl_array_t **new_ext_cis,
-                                          jl_array_t **method_roots_list, jl_array_t **ext_targets, jl_array_t **edges)
+                                          jl_array_t **method_roots_list, jl_array_t **ext_targets, jl_array_t **edges,
+                                          jl_query_cache *query_cache)
 {
     // extext_methods: [method1, ...], worklist-owned "extending external" methods added to functions owned by modules outside the worklist
     // ext_targets: [invokesig1, callee1, matches1, ...] non-worklist callees of worklist-owned methods
@@ -2551,7 +2568,7 @@ static void jl_prepare_serialization_data(jl_array_t *mod_array, jl_array_t *new
     assert(edges_map == NULL);
 
     // Save the inferred code from newly inferred, external methods
-    *new_ext_cis = queue_external_cis(newly_inferred);
+    *new_ext_cis = queue_external_cis(newly_inferred, query_cache);
 
     // Collect method extensions and edges data
     JL_GC_PUSH1(&edges_map);
@@ -2590,7 +2607,8 @@ static void jl_prepare_serialization_data(jl_array_t *mod_array, jl_array_t *new
 static void jl_save_system_image_to_stream(ios_t *f, jl_array_t *mod_array,
                                            jl_array_t *worklist, jl_array_t *extext_methods,
                                            jl_array_t *new_ext_cis, jl_array_t *method_roots_list,
-                                           jl_array_t *ext_targets, jl_array_t *edges) JL_GC_DISABLED
+                                           jl_array_t *ext_targets, jl_array_t *edges,
+                                           jl_query_cache *query_cache) JL_GC_DISABLED
 {
     htable_new(&field_replace, 0);
     // strip metadata and IR when requested
@@ -2617,6 +2635,7 @@ static void jl_save_system_image_to_stream(ios_t *f, jl_array_t *mod_array,
     ios_mem(&gvar_record, 0);
     ios_mem(&fptr_record, 0);
     jl_serializer_state s = {0};
+    s.query_cache = query_cache;
     s.incremental = !(worklist == NULL);
     s.s = &sysimg;
     s.const_data = &const_data;
@@ -2947,12 +2966,15 @@ JL_DLLEXPORT void jl_create_system_image(void **_native_data, jl_array_t *workli
     int64_t datastartpos = 0;
     JL_GC_PUSH6(&mod_array, &extext_methods, &new_ext_cis, &method_roots_list, &ext_targets, &edges);
 
+    jl_query_cache query_cache;
+    init_query_cache(&query_cache);
+
     if (worklist) {
         mod_array = jl_get_loaded_modules();  // __toplevel__ modules loaded in this session (from Base.loaded_modules_array)
         // Generate _native_data`
         if (_native_data != NULL) {
             jl_prepare_serialization_data(mod_array, newly_inferred, jl_worklist_key(worklist),
-                                          &extext_methods, &new_ext_cis, NULL, NULL, NULL);
+                                          &extext_methods, &new_ext_cis, NULL, NULL, NULL, &query_cache);
             jl_precompile_toplevel_module = (jl_module_t*)jl_array_ptr_ref(worklist, jl_array_len(worklist)-1);
             *_native_data = jl_precompile_worklist(worklist, extext_methods, new_ext_cis);
             jl_precompile_toplevel_module = NULL;
@@ -2981,7 +3003,7 @@ JL_DLLEXPORT void jl_create_system_image(void **_native_data, jl_array_t *workli
     if (worklist) {
         htable_new(&relocatable_ext_cis, 0);
         jl_prepare_serialization_data(mod_array, newly_inferred, jl_worklist_key(worklist),
-                                      &extext_methods, &new_ext_cis, &method_roots_list, &ext_targets, &edges);
+                                      &extext_methods, &new_ext_cis, &method_roots_list, &ext_targets, &edges, &query_cache);
         if (!emit_split) {
             write_int32(f, 0); // No clone_targets
             write_padding(f, LLT_ALIGN(ios_pos(f), JL_CACHE_BYTE_ALIGNMENT) - ios_pos(f));
@@ -2993,7 +3015,7 @@ JL_DLLEXPORT void jl_create_system_image(void **_native_data, jl_array_t *workli
     }
     if (_native_data != NULL)
         native_functions = *_native_data;
-    jl_save_system_image_to_stream(ff, mod_array, worklist, extext_methods, new_ext_cis, method_roots_list, ext_targets, edges);
+    jl_save_system_image_to_stream(ff, mod_array, worklist, extext_methods, new_ext_cis, method_roots_list, ext_targets, edges, &query_cache);
     if (_native_data != NULL)
         native_functions = NULL;
     if (worklist)
@@ -3024,6 +3046,8 @@ JL_DLLEXPORT void jl_create_system_image(void **_native_data, jl_array_t *workli
         }
     }
 
+    destroy_query_cache(&query_cache);
+
     JL_GC_POP();
     *s = f;
     if (emit_split)

src/staticdata_utils.c

@@ -104,62 +104,80 @@ JL_DLLEXPORT void jl_push_newly_inferred(jl_value_t* ci)
     JL_UNLOCK(&newly_inferred_mutex);
 }
 
-
 // compute whether a type references something internal to worklist
 // and thus could not have existed before deserialize
 // and thus does not need delayed unique-ing
-static int type_in_worklist(jl_value_t *v) JL_NOTSAFEPOINT
+static int type_in_worklist(jl_value_t *v, jl_query_cache *cache) JL_NOTSAFEPOINT
 {
     if (jl_object_in_image(v))
         return 0; // fast-path for rejection
+
+    void *cached = HT_NOTFOUND;
+    if (cache != NULL)
+        cached = ptrhash_get(&cache->type_in_worklist, v);
+
+    // fast-path for memoized results
+    if (cached != HT_NOTFOUND)
+        return cached == v;
+
+    int result = 0;
     if (jl_is_uniontype(v)) {
         jl_uniontype_t *u = (jl_uniontype_t*)v;
-        return type_in_worklist(u->a) ||
-               type_in_worklist(u->b);
+        result = type_in_worklist(u->a, cache) ||
+                 type_in_worklist(u->b, cache);
     }
     else if (jl_is_unionall(v)) {
         jl_unionall_t *ua = (jl_unionall_t*)v;
-        return type_in_worklist((jl_value_t*)ua->var) ||
-               type_in_worklist(ua->body);
+        result = type_in_worklist((jl_value_t*)ua->var, cache) ||
+                 type_in_worklist(ua->body, cache);
     }
     else if (jl_is_typevar(v)) {
         jl_tvar_t *tv = (jl_tvar_t*)v;
-        return type_in_worklist(tv->lb) ||
-               type_in_worklist(tv->ub);
+        result = type_in_worklist(tv->lb, cache) ||
+                 type_in_worklist(tv->ub, cache);
     }
     else if (jl_is_vararg(v)) {
         jl_vararg_t *tv = (jl_vararg_t*)v;
-        if (tv->T && type_in_worklist(tv->T))
-            return 1;
-        if (tv->N && type_in_worklist(tv->N))
-            return 1;
+        result = ((tv->T && type_in_worklist(tv->T, cache)) ||
+                  (tv->N && type_in_worklist(tv->N, cache)));
     }
     else if (jl_is_datatype(v)) {
         jl_datatype_t *dt = (jl_datatype_t*)v;
-        if (!jl_object_in_image((jl_value_t*)dt->name))
-            return 1;
-        jl_svec_t *tt = dt->parameters;
-        size_t i, l = jl_svec_len(tt);
-        for (i = 0; i < l; i++)
-            if (type_in_worklist(jl_tparam(dt, i)))
-                return 1;
+        if (!jl_object_in_image((jl_value_t*)dt->name)) {
+            result = 1;
+        }
+        else {
+            jl_svec_t *tt = dt->parameters;
+            size_t i, l = jl_svec_len(tt);
+            for (i = 0; i < l; i++) {
+                if (type_in_worklist(jl_tparam(dt, i), cache)) {
+                    result = 1;
+                    break;
+                }
+            }
+        }
     }
     else {
-        return type_in_worklist(jl_typeof(v));
+        return type_in_worklist(jl_typeof(v), cache);
     }
-    return 0;
+
+    // Memoize result
+    if (cache != NULL)
+        ptrhash_put(&cache->type_in_worklist, (void*)v, result ? (void*)v : NULL);
+
+    return result;
 }
 
 // When we infer external method instances, ensure they link back to the
 // package. Otherwise they might be, e.g., for external macros.
 // Implements Tarjan's SCC (strongly connected components) algorithm, simplified to remove the count variable
-static int has_backedge_to_worklist(jl_method_instance_t *mi, htable_t *visited, arraylist_t *stack)
+static int has_backedge_to_worklist(jl_method_instance_t *mi, htable_t *visited, arraylist_t *stack, jl_query_cache *query_cache)
 {
     jl_module_t *mod = mi->def.module;
     if (jl_is_method(mod))
         mod = ((jl_method_t*)mod)->module;
     assert(jl_is_module(mod));
-    if (jl_atomic_load_relaxed(&mi->precompiled) || !jl_object_in_image((jl_value_t*)mod) || type_in_worklist(mi->specTypes)) {
+    if (jl_atomic_load_relaxed(&mi->precompiled) || !jl_object_in_image((jl_value_t*)mod) || type_in_worklist(mi->specTypes, query_cache)) {
         return 1;
     }
     if (!mi->backedges) {
@@ -182,7 +200,7 @@ static int has_backedge_to_worklist(jl_method_instance_t *mi, htable_t *visited,
     while (i < n) {
         jl_method_instance_t *be;
         i = get_next_edge(mi->backedges, i, NULL, &be);
-        int child_found = has_backedge_to_worklist(be, visited, stack);
+        int child_found = has_backedge_to_worklist(be, visited, stack, query_cache);
         if (child_found == 1 || child_found == 2) {
             // found what we were looking for, so terminate early
             found = 1;
@@ -225,7 +243,7 @@ static int is_relocatable_ci(htable_t *relocatable_ext_cis, jl_code_instance_t *
 // from the worklist or explicitly added by a `precompile` statement, and
 // (4) are the most recently computed result for that method.
 // These will be preserved in the image.
-static jl_array_t *queue_external_cis(jl_array_t *list)
+static jl_array_t *queue_external_cis(jl_array_t *list, jl_query_cache *query_cache)
 {
     if (list == NULL)
         return NULL;
@@ -246,7 +264,7 @@ static jl_array_t *queue_external_cis(jl_array_t *list)
         jl_method_instance_t *mi = ci->def;
         jl_method_t *m = mi->def.method;
         if (jl_atomic_load_relaxed(&ci->inferred) && jl_is_method(m) && jl_object_in_image((jl_value_t*)m->module)) {
-            int found = has_backedge_to_worklist(mi, &visited, &stack);
+            int found = has_backedge_to_worklist(mi, &visited, &stack, query_cache);
             assert(found == 0 || found == 1 || found == 2);
             assert(stack.len == 0);
             if (found == 1 && jl_atomic_load_relaxed(&ci->max_world) == ~(size_t)0) {