Extend backdating checks to imports and globals

Compiler/src/Compiler.jl

@@ -44,7 +44,7 @@ using Core: ABIOverride, Builtin, CodeInstance, IntrinsicFunction, MethodInstanc
     typename, unsafe_write, write, stdout, stderr
 
 using Base: @_foldable_meta, @_gc_preserve_begin, @_gc_preserve_end, @nospecializeinfer,
-    PARTITION_KIND_GLOBAL, PARTITION_KIND_UNDEF_CONST, PARTITION_KIND_BACKDATED_CONST, PARTITION_KIND_DECLARED,
+    PARTITION_KIND_GLOBAL, PARTITION_KIND_UNDEF_CONST, PARTITION_KIND_BACKDATED_CONST, PARTITION_KIND_BACKDATED_IMPORT, PARTITION_KIND_BACKDATED_GLOBAL, PARTITION_KIND_DECLARED,
     PARTITION_FLAG_DEPWARN,
     Base, BitVector, Bottom, Callable, DataTypeFieldDesc,
     EffectsOverride, Filter, Generator, NUM_EFFECTS_OVERRIDES,
@@ -55,7 +55,7 @@ using Base: @_foldable_meta, @_gc_preserve_begin, @_gc_preserve_end, @nospeciali
     datatype_pointerfree, decode_effects_override, diff_names, fieldindex, visit,
     generating_output, get_nospecializeinfer_sig, get_world_counter, has_free_typevars,
     hasgenerator, hasintersect, indexed_iterate, isType, is_file_tracked, is_function_def,
-    is_meta_expr, is_meta_expr_head, is_nospecialized, is_nospecializeinfer, is_defined_const_binding,
+    is_meta_expr, is_meta_expr_head, is_nospecialized, is_nospecializeinfer, is_backdated, is_defined_const_binding,
     is_some_const_binding, is_some_guard, is_some_imported, is_some_explicit_imported, is_some_binding_imported, is_valid_intrinsic_elptr,
     isbitsunion, isconcretedispatch, isdispatchelem, isexpr, isfieldatomic, isidentityfree,
     iskindtype, ismutabletypename, ismutationfree, issingletontype, isvarargtype, isvatuple,

Compiler/src/abstractinterpretation.jl

@@ -3650,12 +3650,13 @@ function abstract_eval_partition_load(interp::Union{AbstractInterpreter,Nothing}
         end
     end
 
+    if is_backdated(kind)
+        # Infer this as guard. We do not want a later definition to retroactively improve
+        # inference results in an earlier world.
+        return RTEffects(Any, UndefVarError, local_getglobal_effects)
+    end
+
     if is_defined_const_binding(kind)
-        if kind == PARTITION_KIND_BACKDATED_CONST
-            # Infer this as guard. We do not want a later const definition to retroactively improve
-            # inference results in an earlier world.
-            return RTEffects(Any, UndefVarError, local_getglobal_effects)
-        end
         rt = Const(partition_restriction(partition))
         return RTEffects(rt, Union{}, Effects(EFFECTS_TOTAL,
             inaccessiblememonly=is_mutation_free_argtype(rt) ? ALWAYS_TRUE : ALWAYS_FALSE,

base/runtime_internals.jl

@@ -246,6 +246,8 @@ const PARTITION_KIND_DECLARED           = 0x8
 const PARTITION_KIND_GUARD              = 0x9
 const PARTITION_KIND_UNDEF_CONST        = 0xa
 const PARTITION_KIND_BACKDATED_CONST    = 0xb
+const PARTITION_KIND_BACKDATED_IMPORT   = 0xc
+const PARTITION_KIND_BACKDATED_GLOBAL   = 0xd
 
 const PARTITION_FLAG_EXPORTED     = 0x10
 const PARTITION_FLAG_DEPRECATED   = 0x20
@@ -256,11 +258,12 @@ const PARTITION_MASK_FLAG         = 0xf0
 
 const BINDING_FLAG_ANY_IMPLICIT_EDGES = 0x8
 
+is_backdated(kind::UInt8) = (kind == PARTITION_KIND_BACKDATED_CONST || kind == PARTITION_KIND_BACKDATED_IMPORT || kind == PARTITION_KIND_BACKDATED_GLOBAL)
 is_defined_const_binding(kind::UInt8) = (kind == PARTITION_KIND_CONST || kind == PARTITION_KIND_CONST_IMPORT || kind == PARTITION_KIND_IMPLICIT_CONST || kind == PARTITION_KIND_BACKDATED_CONST)
 is_some_const_binding(kind::UInt8) = (is_defined_const_binding(kind) || kind == PARTITION_KIND_UNDEF_CONST)
-is_some_imported(kind::UInt8) = (kind == PARTITION_KIND_IMPLICIT_GLOBAL || kind == PARTITION_KIND_IMPLICIT_CONST || kind == PARTITION_KIND_EXPLICIT || kind == PARTITION_KIND_IMPORTED)
+is_some_imported(kind::UInt8) = (kind == PARTITION_KIND_IMPLICIT_GLOBAL || kind == PARTITION_KIND_IMPLICIT_CONST || kind == PARTITION_KIND_EXPLICIT || kind == PARTITION_KIND_IMPORTED || kind == PARTITION_KIND_BACKDATED_IMPORT)
 is_some_implicit(kind::UInt8) = (kind == PARTITION_KIND_IMPLICIT_GLOBAL || kind == PARTITION_KIND_IMPLICIT_CONST || kind == PARTITION_KIND_GUARD || kind == PARTITION_KIND_FAILED)
-is_some_explicit_imported(kind::UInt8) = (kind == PARTITION_KIND_EXPLICIT || kind == PARTITION_KIND_IMPORTED)
+is_some_explicit_imported(kind::UInt8) = (kind == PARTITION_KIND_EXPLICIT || kind == PARTITION_KIND_IMPORTED || kind == PARTITION_KIND_BACKDATED_IMPORT)
 is_some_binding_imported(kind::UInt8) = is_some_explicit_imported(kind) || kind == PARTITION_KIND_IMPLICIT_GLOBAL
 is_some_guard(kind::UInt8) = (kind == PARTITION_KIND_GUARD || kind == PARTITION_KIND_FAILED || kind == PARTITION_KIND_UNDEF_CONST)
 

base/show.jl

@@ -3309,6 +3309,12 @@ function print_partition(io::IO, partition::Core.BindingPartition)
     if kind == PARTITION_KIND_BACKDATED_CONST
         print(io, "backdated constant binding to ")
         print(io, partition_restriction(partition))
+    elseif kind == PARTITION_KIND_BACKDATED_IMPORT
+        print(io, "backdated explicit `import` from ")
+        print(io, partition_restriction(partition).globalref)
+    elseif kind == PARTITION_KIND_BACKDATED_GLOBAL
+        print(io, "backdated global variable with type ")
+        print(io, partition_restriction(partition))
     elseif kind == PARTITION_KIND_CONST
         print(io, "constant binding to ")
         print(io, partition_restriction(partition))

src/ast.c

@@ -1224,9 +1224,10 @@ JL_DLLEXPORT jl_value_t *jl_fl_lower(jl_value_t *expr, jl_module_t *inmodule,
 JL_DLLEXPORT jl_value_t *jl_lower(jl_value_t *expr, jl_module_t *inmodule,
                                   const char *filename, int line, size_t world, bool_t warn)
 {
-    jl_value_t *core_lower = NULL;
-    if (jl_core_module)
-        core_lower = jl_get_global_value(jl_core_module, jl_symbol("_lower"), jl_current_task->world_age);
+    if (!jl_core_module || !jl_boundp(jl_core_module, jl_symbol("_lower"), jl_current_task->world_age)) {
+        return jl_fl_lower(expr, inmodule, filename, line, world, warn);
+    }
+    jl_value_t *core_lower = jl_get_global_value(jl_core_module, jl_symbol("_lower"), jl_current_task->world_age);
     if (!core_lower || core_lower == jl_nothing) {
         return jl_fl_lower(expr, inmodule, filename, line, world, warn);
     }

src/julia.h

@@ -694,11 +694,11 @@ typedef struct _jl_weakref_t {
 //
 // We may make this list more permissive in the future.
 //
-// Finally, PARTITION_KIND_BACKDATED_CONST is a special case, and the only case where we may replace an
-// existing partition by a different partition kind in the same world age. As such, it needs special
-// support in inference. Any partition kind that may be replaced by a PARTITION_KIND_BACKDATED_CONST
-// must be inferred accordingly. PARTITION_KIND_BACKDATED_CONST is intended as a temporary compatibility
-// measure. The following kinds may be replaced by PARTITION_KIND_BACKDATED_CONST:
+// Finally, PARTITION_KIND_BACKDATED_* are special cases, and the only cases where we may replace an
+// existing partition by a different partition kind in the same world age. As such, they need special
+// support in inference. Any partition kind that may be replaced by a PARTITION_KIND_BACKDATED_*
+// must be inferred accordingly. PARTITION_KIND_BACKDATED_* are intended as a temporary compatibility
+// measure. The following kinds may be replaced by any backdated partition kind:
 //  - PARTITION_KIND_GUARD
 //  - PARTITION_KIND_FAILED
 //  - PARTITION_KIND_DECLARED
@@ -743,11 +743,17 @@ enum jl_partition_kind {
     // Backated constant. A constant that was backdated for compatibility. In all other
     // ways equivalent to PARTITION_KIND_CONST, but prints a warning on access
     PARTITION_KIND_BACKDATED_CONST = 0xb,
+    // Backdated import. An explicit import that was backdated for compatibility. In all other
+    // ways equivalent to PARTITION_KIND_IMPORTED, but prints a warning on access
+    PARTITION_KIND_BACKDATED_IMPORT = 0xc,
+    // Backdated global. A global that was backdated for compatibility. In all other
+    // ways equivalent to PARTITION_KIND_GLOBAL, but prints a warning on access
+    PARTITION_KIND_BACKDATED_GLOBAL = 0xd,
 
     // This is not a real binding kind, but can be used to ask for a re-resolution
     // of the implicit binding kind
-    PARTITION_FAKE_KIND_IMPLICIT_RECOMPUTE = 0xc,
-    PARTITION_FAKE_KIND_CYCLE = 0xd
+    PARTITION_FAKE_KIND_IMPLICIT_RECOMPUTE = 0xe,
+    PARTITION_FAKE_KIND_CYCLE = 0xf
 };
 
 static const uint8_t PARTITION_MASK_KIND = 0x0f;

src/julia_internal.h

@@ -979,6 +979,9 @@ JL_DLLEXPORT jl_binding_partition_t *jl_replace_binding_locked(jl_binding_t *b J
     jl_binding_partition_t *old_bpart, jl_value_t *restriction_val, enum jl_partition_kind kind, size_t new_world) JL_GLOBALLY_ROOTED;
 JL_DLLEXPORT jl_binding_partition_t *jl_replace_binding_locked2(jl_binding_t *b JL_PROPAGATES_ROOT,
     jl_binding_partition_t *old_bpart, jl_value_t *restriction_val, size_t kind, size_t new_world) JL_GLOBALLY_ROOTED;
+jl_binding_partition_t *jl_backdate_binding_partition(jl_binding_t *b JL_PROPAGATES_ROOT,
+    jl_binding_partition_t *bpart, jl_binding_partition_t *new_bpart,
+    jl_value_t *restriction, enum jl_partition_kind backdated_kind, size_t new_world) JL_GLOBALLY_ROOTED;
 JL_DLLEXPORT void jl_update_loaded_bpart(jl_binding_t *b, jl_binding_partition_t *bpart);
 extern jl_array_t *jl_module_init_order JL_GLOBALLY_ROOTED;
 extern htable_t jl_current_modules JL_GLOBALLY_ROOTED;
@@ -998,11 +1001,11 @@ jl_method_t *jl_make_opaque_closure_method(jl_module_t *module, jl_value_t *name
 JL_DLLEXPORT int jl_is_valid_oc_argtype(jl_tupletype_t *argt, jl_method_t *source);
 
 STATIC_INLINE int jl_bkind_is_some_import(enum jl_partition_kind kind) JL_NOTSAFEPOINT {
-    return kind == PARTITION_KIND_IMPLICIT_CONST || kind == PARTITION_KIND_IMPLICIT_GLOBAL || kind == PARTITION_KIND_EXPLICIT || kind == PARTITION_KIND_IMPORTED;
+    return kind == PARTITION_KIND_IMPLICIT_CONST || kind == PARTITION_KIND_IMPLICIT_GLOBAL || kind == PARTITION_KIND_EXPLICIT || kind == PARTITION_KIND_IMPORTED || kind == PARTITION_KIND_BACKDATED_IMPORT;
 }
 
 STATIC_INLINE int jl_bkind_is_some_explicit_import(enum jl_partition_kind kind) JL_NOTSAFEPOINT {
-    return kind == PARTITION_KIND_EXPLICIT || kind == PARTITION_KIND_IMPORTED;
+    return kind == PARTITION_KIND_EXPLICIT || kind == PARTITION_KIND_IMPORTED || kind == PARTITION_KIND_BACKDATED_IMPORT;
 }
 
 STATIC_INLINE int jl_bkind_is_some_guard(enum jl_partition_kind kind) JL_NOTSAFEPOINT {
@@ -1025,6 +1028,10 @@ STATIC_INLINE int jl_bkind_is_real_constant(enum jl_partition_kind kind) JL_NOTS
     return kind == PARTITION_KIND_IMPLICIT_CONST || kind == PARTITION_KIND_CONST || kind == PARTITION_KIND_CONST_IMPORT;
 }
 
+STATIC_INLINE int jl_bkind_is_backdated(enum jl_partition_kind kind) JL_NOTSAFEPOINT {
+    return kind == PARTITION_KIND_BACKDATED_CONST || kind == PARTITION_KIND_BACKDATED_IMPORT || kind == PARTITION_KIND_BACKDATED_GLOBAL;
+}
+
 JL_DLLEXPORT jl_binding_partition_t *jl_get_binding_partition(jl_binding_t *b JL_PROPAGATES_ROOT, size_t world) JL_GLOBALLY_ROOTED;
 JL_DLLEXPORT jl_binding_partition_t *jl_get_binding_partition_with_hint(jl_binding_t *b JL_PROPAGATES_ROOT, jl_binding_partition_t *previous_part, size_t world) JL_GLOBALLY_ROOTED;
 JL_DLLEXPORT jl_binding_partition_t *jl_get_binding_partition_all(jl_binding_t *b JL_PROPAGATES_ROOT, size_t min_world, size_t max_world) JL_GLOBALLY_ROOTED;
@@ -1059,6 +1066,21 @@ STATIC_INLINE void jl_walk_binding_inplace(jl_binding_t **bnd, jl_binding_partit
     }
 }
 
+extern void check_backdated_binding(jl_binding_t *b, enum jl_partition_kind kind) JL_NOTSAFEPOINT;
+
+STATIC_INLINE void jl_walk_binding_inplace_stop_at_backdated(jl_binding_t **bnd, jl_binding_partition_t **bpart, size_t world, int stop_at_backdated) JL_NOTSAFEPOINT
+{
+    while (1) {
+        enum jl_partition_kind kind = jl_binding_kind(*bpart);
+        if (stop_at_backdated && jl_bkind_is_backdated(kind))
+            return;
+        if (!jl_bkind_is_some_explicit_import(kind) && kind != PARTITION_KIND_IMPLICIT_GLOBAL)
+            return;
+        *bnd = (jl_binding_t*)(*bpart)->restriction;
+        *bpart = jl_get_binding_partition(*bnd, world);
+    }
+}
+
 STATIC_INLINE void jl_walk_binding_inplace_depwarn(jl_binding_t **bnd, jl_binding_partition_t **bpart, size_t world, int *depwarn) JL_NOTSAFEPOINT
 {
     int passed_explicit = 0;