add trimming of new usings_backedges and scanned_methods fields (#57879)

(cherry picked from commit 8fd3fb1)

Author: JeffBezanson

src/staticdata.c

@@ -851,8 +851,14 @@ static void jl_queue_module_for_serialization(jl_serializer_state *s, jl_module_
         jl_queue_for_serialization(s, module_usings_getmod(m, i));
     }
 
-    jl_queue_for_serialization(s, m->usings_backedges);
-    jl_queue_for_serialization(s, m->scanned_methods);
+    if (jl_options.trim || jl_options.strip_ir) {
+        record_field_change((jl_value_t**)&m->usings_backedges, jl_nothing);
+        record_field_change((jl_value_t**)&m->scanned_methods, jl_nothing);
+    }
+    else {
+        jl_queue_for_serialization(s, m->usings_backedges);
+        jl_queue_for_serialization(s, m->scanned_methods);
+    }
 }
 
 // Anything that requires uniquing or fixing during deserialization needs to be "toplevel"
@@ -1367,10 +1373,10 @@ static void jl_write_module(jl_serializer_state *s, uintptr_t item, jl_module_t
         newm->line = 0;
     newm->usings_backedges = NULL;
     arraylist_push(&s->relocs_list, (void*)(reloc_offset + offsetof(jl_module_t, usings_backedges)));
-    arraylist_push(&s->relocs_list, (void*)backref_id(s, m->usings_backedges, s->link_ids_relocs));
+    arraylist_push(&s->relocs_list, (void*)backref_id(s, get_replaceable_field(&m->usings_backedges, 1), s->link_ids_relocs));
     newm->scanned_methods = NULL;
     arraylist_push(&s->relocs_list, (void*)(reloc_offset + offsetof(jl_module_t, scanned_methods)));
-    arraylist_push(&s->relocs_list, (void*)backref_id(s, m->scanned_methods, s->link_ids_relocs));
+    arraylist_push(&s->relocs_list, (void*)backref_id(s, get_replaceable_field(&m->scanned_methods, 1), s->link_ids_relocs));
 
     // After reload, everything that has happened in this process happened semantically at
     // (for .incremental) or before jl_require_world, so reset this flag.
@@ -3635,7 +3641,7 @@ static int jl_validate_binding_partition(jl_binding_t *b, jl_binding_partition_t
         jl_sym_t *name = b->globalref->name;
         JL_LOCK(&mod->lock);
         jl_atomic_store_release(&mod->export_set_changed_since_require_world, 1);
-        if (mod->usings_backedges) {
+        if (mod->usings_backedges != jl_nothing) {
             for (size_t i = 0; i < jl_array_len(mod->usings_backedges); i++) {
                 jl_module_t *edge = (jl_module_t*)jl_array_ptr_ref(mod->usings_backedges, i);
                 jl_binding_t *importee = jl_get_module_binding(edge, name, 0);

test/trimming/trimming.jl

@@ -4,7 +4,7 @@ let exe_suffix = splitext(Base.julia_exename())[2]
 
     hello_exe = joinpath(@__DIR__, "hello" * exe_suffix)
     @test readchomp(`$hello_exe`) == "Hello, world!"
-    @test filesize(hello_exe) < 20_000_000
+    @test filesize(hello_exe) < 2000000
 
     basic_jll_exe = joinpath(@__DIR__, "basic_jll" * exe_suffix)
     lines = split(readchomp(`$basic_jll_exe`), "\n")