remove precompile mutation step from staticdata (#48309)

Make sure things are properly ordered here, so that when serializing,
nothing is mutating the system at the same time.

Fix #48047

Author: vtjnash

src/gf.c

@@ -281,11 +281,9 @@ jl_code_info_t *jl_type_infer(jl_method_instance_t *mi, size_t world, int force)
         return NULL;
     jl_task_t *ct = jl_current_task;
     if (ct->reentrant_inference == (uint16_t)-1) {
-        // TODO: We should avoid attempting to re-inter inference here at all
-        // and turn on this warning, but that requires further refactoring
-        // of the precompile code, so for now just catch that case here.
-        //jl_printf(JL_STDERR, "ERROR: Attempted to enter inference while writing out image.");
-        return NULL;
+        // We must avoid attempting to re-enter inference here
+        assert(0 && "attempted to enter inference while writing out image");
+        abort();
     }
     if (ct->reentrant_inference > 2)
         return NULL;
@@ -487,6 +485,7 @@ int foreach_mtable_in_module(
                         // this is the original/primary binding for the type (name/wrapper)
                         jl_methtable_t *mt = tn->mt;
                         if (mt != NULL && (jl_value_t*)mt != jl_nothing && mt != jl_type_type_mt && mt != jl_nonfunction_mt) {
+                            assert(mt->module == m);
                             if (!visit(mt, env))
                                 return 0;
                         }
@@ -500,6 +499,15 @@ int foreach_mtable_in_module(
                             return 0;
                     }
                 }
+                else if (jl_is_mtable(v)) {
+                    jl_methtable_t *mt = (jl_methtable_t*)v;
+                    if (mt->module == m && mt->name == name) {
+                        // this is probably an external method table here, so let's
+                        // assume so as there is no way to precisely distinguish them
+                        if (!visit(mt, env))
+                            return 0;
+                    }
+                }
             }
         }
         table = jl_atomic_load_relaxed(&m->bindings);

src/precompile_utils.c

@@ -132,6 +132,8 @@ static int compile_all_collect__(jl_typemap_entry_t *ml, void *env)
 {
     jl_array_t *allmeths = (jl_array_t*)env;
     jl_method_t *m = ml->func.method;
+    if (m->external_mt)
+        return 1;
     if (m->source) {
         // method has a non-generated definition; can be compiled generically
         jl_array_ptr_1d_push(allmeths, (jl_value_t*)m);
@@ -204,6 +206,8 @@ static int precompile_enq_specialization_(jl_method_instance_t *mi, void *closur
 static int precompile_enq_all_specializations__(jl_typemap_entry_t *def, void *closure)
 {
     jl_method_t *m = def->func.method;
+    if (m->external_mt)
+        return 1;
     if ((m->name == jl_symbol("__init__") || m->ccallable) && jl_is_dispatch_tupletype(m->sig)) {
         // ensure `__init__()` and @ccallables get strongly-hinted, specialized, and compiled
         jl_method_instance_t *mi = jl_specializations_get_linfo(m, m->sig, jl_emptysvec);

src/staticdata.c

@@ -2170,50 +2170,52 @@ JL_DLLEXPORT jl_value_t *jl_as_global_root(jl_value_t *val JL_MAYBE_UNROOTED)
 }
 
 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_specializations, jl_array_t **method_roots_list,
-                                          jl_array_t **ext_targets, jl_array_t **edges)
+                           /* outputs */  jl_array_t **extext_methods, jl_array_t **new_specializations,
+                                          jl_array_t **method_roots_list, jl_array_t **ext_targets, jl_array_t **edges)
 {
     // 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
     //              ordinary dispatch: invokesig=NULL, callee is MethodInstance
     //              `invoke` dispatch: invokesig is signature, callee is MethodInstance
     //              abstract call: callee is signature
     // edges: [caller1, ext_targets_indexes1, ...] for worklist-owned methods calling external methods
-
     assert(edges_map == NULL);
-    JL_GC_PUSH1(&edges_map);
 
-    // Save the inferred code from newly inferred, external methods
     htable_new(&external_mis, 0);  // we need external_mis until after `jl_collect_edges` finishes
+    // Save the inferred code from newly inferred, external methods
     *new_specializations = queue_external_cis(newly_inferred);
-    // Collect the new method roots
-    htable_t methods_with_newspecs;
-    htable_new(&methods_with_newspecs, 0);
-    jl_collect_methods(&methods_with_newspecs, *new_specializations);
-    *method_roots_list = jl_alloc_vec_any(0);
-    jl_collect_new_roots(*method_roots_list, &methods_with_newspecs, worklist_key);
-    htable_free(&methods_with_newspecs);
 
     // Collect method extensions and edges data
-    edges_map = jl_alloc_vec_any(0);
+    JL_GC_PUSH1(&edges_map);
+    if (edges)
+        edges_map = jl_alloc_vec_any(0);
     *extext_methods = jl_alloc_vec_any(0);
+    jl_collect_methtable_from_mod(jl_type_type_mt, *extext_methods);
+    jl_collect_methtable_from_mod(jl_nonfunction_mt, *extext_methods);
     size_t i, len = jl_array_len(mod_array);
     for (i = 0; i < len; i++) {
         jl_module_t *m = (jl_module_t*)jl_array_ptr_ref(mod_array, i);
         assert(jl_is_module(m));
         if (m->parent == m) // some toplevel modules (really just Base) aren't actually
             jl_collect_extext_methods_from_mod(*extext_methods, m);
     }
-    jl_collect_methtable_from_mod(*extext_methods, jl_type_type_mt);
-    jl_collect_missing_backedges(jl_type_type_mt);
-    jl_collect_methtable_from_mod(*extext_methods, jl_nonfunction_mt);
-    jl_collect_missing_backedges(jl_nonfunction_mt);
-    // jl_collect_extext_methods_from_mod and jl_collect_missing_backedges also accumulate data in callers_with_edges.
-    // Process this to extract `edges` and `ext_targets`.
-    *ext_targets = jl_alloc_vec_any(0);
-    *edges = jl_alloc_vec_any(0);
-    jl_collect_edges(*edges, *ext_targets);
+
+    if (edges) {
+        jl_collect_missing_backedges(jl_type_type_mt);
+        jl_collect_missing_backedges(jl_nonfunction_mt);
+        // jl_collect_extext_methods_from_mod and jl_collect_missing_backedges also accumulate data in callers_with_edges.
+        // Process this to extract `edges` and `ext_targets`.
+        *ext_targets = jl_alloc_vec_any(0);
+        *edges = jl_alloc_vec_any(0);
+        *method_roots_list = jl_alloc_vec_any(0);
+        // Collect the new method roots
+        htable_t methods_with_newspecs;
+        htable_new(&methods_with_newspecs, 0);
+        jl_collect_methods(&methods_with_newspecs, *new_specializations);
+        jl_collect_new_roots(*method_roots_list, &methods_with_newspecs, worklist_key);
+        htable_free(&methods_with_newspecs);
+        jl_collect_edges(*edges, *ext_targets);
+    }
     htable_free(&external_mis);
     assert(edges_map == NULL); // jl_collect_edges clears this when done
 
@@ -2501,9 +2503,8 @@ static void jl_save_system_image_to_stream(ios_t *f,
     jl_gc_enable(en);
 }
 
-static void jl_write_header_for_incremental(ios_t *f, jl_array_t *worklist, jl_array_t **mod_array, jl_array_t **udeps, int64_t *srctextpos, int64_t *checksumpos)
+static void jl_write_header_for_incremental(ios_t *f, jl_array_t *worklist, jl_array_t *mod_array, jl_array_t **udeps, int64_t *srctextpos, int64_t *checksumpos)
 {
-    *mod_array = jl_get_loaded_modules();  // __toplevel__ modules loaded in this session (from Base.loaded_modules_array)
     assert(jl_precompile_toplevel_module == NULL);
     jl_precompile_toplevel_module = (jl_module_t*)jl_array_ptr_ref(worklist, jl_array_len(worklist)-1);
 
@@ -2519,7 +2520,7 @@ static void jl_write_header_for_incremental(ios_t *f, jl_array_t *worklist, jl_a
     // write description of requirements for loading (modules that must be pre-loaded if initialization is to succeed)
     // this can return errors during deserialize,
     // best to keep it early (before any actual initialization)
-    write_mod_list(f, *mod_array);
+    write_mod_list(f, mod_array);
 }
 
 JL_DLLEXPORT void jl_create_system_image(void **_native_data, jl_array_t *worklist, bool_t emit_split,
@@ -2550,49 +2551,58 @@ JL_DLLEXPORT void jl_create_system_image(void **_native_data, jl_array_t *workli
     int64_t checksumpos_ff = 0;
     int64_t datastartpos = 0;
     JL_GC_PUSH6(&mod_array, &extext_methods, &new_specializations, &method_roots_list, &ext_targets, &edges);
-    if (worklist) {
-        jl_write_header_for_incremental(f, worklist, &mod_array, udeps, srctextpos, &checksumpos);
-        if (emit_split) {
-            checksumpos_ff = write_header(ff, 1);
-            write_uint8(ff, jl_cache_flags());
-            write_mod_list(ff, mod_array);
-        } else {
-            checksumpos_ff = checksumpos;
-        }
-        {
-            // make sure we don't run any Julia code concurrently after this point
-            jl_gc_enable_finalizers(ct, 0);
-            assert(ct->reentrant_inference == 0);
-            ct->reentrant_inference = (uint16_t)-1;
-        }
-        jl_prepare_serialization_data(mod_array, newly_inferred, jl_worklist_key(worklist), &extext_methods, &new_specializations, &method_roots_list, &ext_targets, &edges);
 
+    if (worklist) {
+        mod_array = jl_get_loaded_modules();  // __toplevel__ modules loaded in this session (from Base.loaded_modules_array)
         // Generate _native_data`
         if (jl_options.outputo || jl_options.outputbc || jl_options.outputunoptbc || jl_options.outputasm) {
+            jl_prepare_serialization_data(mod_array, newly_inferred, jl_worklist_key(worklist),
+                                          &extext_methods, &new_specializations, NULL, NULL, NULL);
             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_specializations);
             jl_precompile_toplevel_module = NULL;
+            extext_methods = NULL;
+            new_specializations = NULL;
         }
+        jl_write_header_for_incremental(f, worklist, mod_array, udeps, srctextpos, &checksumpos);
+        if (emit_split) {
+            checksumpos_ff = write_header(ff, 1);
+            write_uint8(ff, jl_cache_flags());
+            write_mod_list(ff, mod_array);
+        }
+        else {
+            checksumpos_ff = checksumpos;
+        }
+    }
+    else {
+        *_native_data = jl_precompile(jl_options.compile_enabled == JL_OPTIONS_COMPILE_ALL);
+    }
 
+    // Make sure we don't run any Julia code concurrently after this point
+    // since it will invalidate our serialization preparations
+    jl_gc_enable_finalizers(ct, 0);
+    assert(ct->reentrant_inference == 0);
+    ct->reentrant_inference = (uint16_t)-1;
+    if (worklist) {
+        jl_prepare_serialization_data(mod_array, newly_inferred, jl_worklist_key(worklist),
+                                      &extext_methods, &new_specializations, &method_roots_list, &ext_targets, &edges);
         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));
-        } else {
+        }
+        else {
             write_padding(ff, LLT_ALIGN(ios_pos(ff), JL_CACHE_BYTE_ALIGNMENT) - ios_pos(ff));
         }
         datastartpos = ios_pos(ff);
-    } else {
-        *_native_data = jl_precompile(jl_options.compile_enabled == JL_OPTIONS_COMPILE_ALL);
     }
     native_functions = *_native_data;
     jl_save_system_image_to_stream(ff, worklist, extext_methods, new_specializations, method_roots_list, ext_targets, edges);
     native_functions = NULL;
-    if (worklist) {
-        // Re-enable running julia code for postoutput hooks, atexit, etc.
-        jl_gc_enable_finalizers(ct, 1);
-        ct->reentrant_inference = 0;
-        jl_precompile_toplevel_module = NULL;
-    }
+    // make sure we don't run any Julia code concurrently before this point
+    // Re-enable running julia code for postoutput hooks, atexit, etc.
+    jl_gc_enable_finalizers(ct, 1);
+    ct->reentrant_inference = 0;
+    jl_precompile_toplevel_module = NULL;
 
     if (worklist) {
         // Go back and update the checksum in the header

src/staticdata_utils.c

@@ -273,12 +273,12 @@ static void jl_collect_methods(htable_t *mset, jl_array_t *new_specializations)
     }
 }
 
-static void jl_collect_new_roots(jl_array_t *roots, htable_t *mset, uint64_t key)
+static void jl_collect_new_roots(jl_array_t *roots, const htable_t *mset, uint64_t key)
 {
     size_t i, sz = mset->size;
     int nwithkey;
     jl_method_t *m;
-    void **table = mset->table;
+    void *const *table = mset->table;
     jl_array_t *newroots = NULL;
     JL_GC_PUSH1(&newroots);
     for (i = 0; i < sz; i += 2) {
@@ -369,6 +369,8 @@ static int jl_collect_methcache_from_mod(jl_typemap_entry_t *ml, void *closure)
     if (s && !jl_object_in_image((jl_value_t*)m->module)) {
         jl_array_ptr_1d_push(s, (jl_value_t*)m);
     }
+    if (edges_map == NULL)
+        return 1;
     jl_svec_t *specializations = m->specializations;
     size_t i, l = jl_svec_len(specializations);
     for (i = 0; i < l; i++) {
@@ -379,60 +381,22 @@ static int jl_collect_methcache_from_mod(jl_typemap_entry_t *ml, void *closure)
     return 1;
 }
 
-static void jl_collect_methtable_from_mod(jl_array_t *s, jl_methtable_t *mt)
+static int jl_collect_methtable_from_mod(jl_methtable_t *mt, void *env)
 {
-    jl_typemap_visitor(mt->defs, jl_collect_methcache_from_mod, (void*)s);
+    if (!jl_object_in_image((jl_value_t*)mt))
+        env = NULL; // do not collect any methods from here
+    jl_typemap_visitor(jl_atomic_load_relaxed(&mt->defs), jl_collect_methcache_from_mod, env);
+    if (env && edges_map)
+        jl_collect_missing_backedges(mt);
+    return 1;
 }
 
 // Collect methods of external functions defined by modules in the worklist
 // "extext" = "extending external"
 // Also collect relevant backedges
 static void jl_collect_extext_methods_from_mod(jl_array_t *s, jl_module_t *m)
 {
-    if (s && !jl_object_in_image((jl_value_t*)m))
-        s = NULL; // do not collect any methods
-    jl_svec_t *table = jl_atomic_load_relaxed(&m->bindings);
-    for (size_t i = 0; i < jl_svec_len(table); i++) {
-        jl_binding_t *b = (jl_binding_t*)jl_svec_ref(table, i);
-        if ((void*)b == jl_nothing)
-            break;
-        jl_sym_t *name = b->globalref->name;
-        if (b->owner == b && b->value && b->constp) {
-            jl_value_t *bv = jl_unwrap_unionall(b->value);
-            if (jl_is_datatype(bv)) {
-                jl_typename_t *tn = ((jl_datatype_t*)bv)->name;
-                if (tn->module == m && tn->name == name && tn->wrapper == b->value) {
-                    jl_methtable_t *mt = tn->mt;
-                    if (mt != NULL &&
-                            (jl_value_t*)mt != jl_nothing &&
-                            (mt != jl_type_type_mt && mt != jl_nonfunction_mt)) {
-                        assert(mt->module == tn->module);
-                        jl_collect_methtable_from_mod(s, mt);
-                        if (s)
-                            jl_collect_missing_backedges(mt);
-                    }
-                }
-            }
-            else if (jl_is_module(b->value)) {
-                jl_module_t *child = (jl_module_t*)b->value;
-                if (child != m && child->parent == m && child->name == name) {
-                    // this is the original/primary binding for the submodule
-                    jl_collect_extext_methods_from_mod(s, (jl_module_t*)b->value);
-                }
-            }
-            else if (jl_is_mtable(b->value)) {
-                jl_methtable_t *mt = (jl_methtable_t*)b->value;
-                if (mt->module == m && mt->name == name) {
-                    // this is probably an external method table, so let's assume so
-                    // as there is no way to precisely distinguish them,
-                    // and the rest of this serializer does not bother
-                    // to handle any method tables specially
-                    jl_collect_methtable_from_mod(s, (jl_methtable_t*)bv);
-                }
-            }
-        }
-        table = jl_atomic_load_relaxed(&m->bindings);
-    }
+    foreach_mtable_in_module(m, jl_collect_methtable_from_mod, s);
 }
 
 static void jl_record_edges(jl_method_instance_t *caller, arraylist_t *wq, jl_array_t *edges)