Emit latestworld world age increments

For method defs, `latestworld` is produced in desugaring rather than closure
conversion for now (our closure conversion doesn't seem to cover the same
cases as lisp lowering yet).

Covers JuliaLang/julia#56523, JuliaLang/julia#56509, JuliaLang/julia#57299.

Also includes changes from JuliaLang/julia#57102 (bpart: Start enforcing minimum
world age for const bparts) and JuliaLang/julia#57150 (bpart: Start enforcing
min_world for global variable definitions) since the lowering changes from those
appear to be amendments to the changes above (missing world age increments).

Co-authored-by: Claire Foster <[email protected]>

Author: mlechu

src/closure_conversion.jl

@@ -355,7 +355,6 @@ function _convert_closures(ctx::ClosureConversionCtx, ex)
                 K"globaldecl"
                 ex[1]
                 _convert_closures(ctx, ex[2])
-                # TODO (null)?
             ]
         else
             makeleaf(ctx, ex, K"TOMBSTONE")
@@ -389,6 +388,7 @@ function _convert_closures(ctx::ClosureConversionCtx, ex)
                     type_for_closure(ctx, ex, name_str, field_syms, field_is_box)
                 if !ctx.is_toplevel_seq_point
                     push!(ctx.toplevel_stmts, closure_type_def)
+                    push!(ctx.toplevel_stmts, @ast ctx ex [K"latestworld_if_toplevel"])
                     closure_type_def = nothing
                 end
                 closure_info = ClosureInfo(closure_type_, field_syms, field_inds)
@@ -413,6 +413,7 @@ function _convert_closures(ctx::ClosureConversionCtx, ex)
                 end
                 @ast ctx ex [K"block"
                     closure_type_def
+                    [K"latestworld_if_toplevel"]
                     closure_type := if isempty(type_params)
                         closure_type_
                     else

src/desugaring.jl

@@ -1177,6 +1177,7 @@ function expand_unionall_def(ctx, srcref, lhs, rhs, is_const=true)
             K"block"
             [K"=" rr [K"where" rhs lhs[2:end]...]]
             [is_const ? K"constdecl" : K"assign_const_if_global" name rr]
+            [K"latestworld_if_toplevel"]
             rr
         ]
     )
@@ -1233,6 +1234,7 @@ function expand_assignment(ctx, ex, is_const=false)
                 K"block"
                 sink_assignment(ctx, ex, rr, expand_forms_2(ctx, rhs))
                 [K"constdecl" lhs rr]
+                [K"latestworld"]
                 [K"removable" rr]
             ]
         else
@@ -1849,6 +1851,17 @@ function expand_call(ctx, ex)
             expand_forms_2(ctx, farg)
             expand_forms_2(ctx, _wrap_unsplatted_args(ctx, ex, args))...
         ]
+    elseif kind(farg) == K"Identifier" && farg.name_val == "include"
+        # world age special case
+        r = ssavar(ctx, ex)
+        @ast ctx ex [K"block"
+            [K"=" r [K"call"
+                expand_forms_2(ctx, farg)
+                expand_forms_2(ctx, args)...
+            ]]
+            [K"latestworld_if_toplevel"]
+            r
+        ]
     else
         @ast ctx ex [K"call"
             expand_forms_2(ctx, farg)
@@ -2321,6 +2334,7 @@ function method_def_expr(ctx, srcref, callex_srcref, method_table,
                 ret_var  # might be `nothing` and hence removed
             ]
         ]
+        [K"latestworld"]
         [K"removable" method_metadata]
     ]
 end
@@ -2449,10 +2463,12 @@ function expand_function_generator(ctx, srcref, callex_srcref, func_name, func_n
     # Code generator definition
     gen_func_method_defs = @ast ctx srcref [K"block"
         [K"function_decl" gen_name]
+        [K"latestworld_if_toplevel"]
         [K"scope_block"(scope_type=:hard)
             [K"method_defs"
                 gen_name
                 [K"block"
+                    [K"latestworld_if_toplevel"]
                     method_def_expr(ctx, srcref, callex_srcref, nothing, SyntaxList(ctx),
                                     gen_arg_names, gen_arg_types, gen_body, nothing)
                 ]
@@ -2786,6 +2802,7 @@ function keyword_function_defs(ctx, srcref, callex_srcref, name_str, typevar_nam
 
     kw_func_method_defs = @ast ctx srcref [K"block"
         [K"function_decl" body_func_name]
+        [K"latestworld"]
         [K"scope_block"(scope_type=:hard)
             [K"method_defs"
                 body_func_name
@@ -2855,6 +2872,7 @@ function expand_function_def(ctx, ex, docs, rewrite_call=identity, rewrite_body=
         end
         return @ast ctx ex [K"block"
             [K"function_decl" name]
+            [K"latestworld"]
             name
         ]
     end
@@ -3091,6 +3109,7 @@ function expand_function_def(ctx, ex, docs, rewrite_call=identity, rewrite_body=
         end
         gen_func_method_defs
         kw_func_method_defs
+        [K"latestworld_if_toplevel"]
         [K"scope_block"(scope_type=:hard)
             [K"method_defs"
                 isnothing(bare_func_name) ? "nothing"::K"core" : bare_func_name
@@ -3408,6 +3427,7 @@ function expand_abstract_or_primitive_type(ctx, ex)
             nothing_(ctx, ex)
             [K"constdecl" name newtype_var]
         ]
+        [K"latestworld"]
         nothing_(ctx, ex)
     ]
 end
@@ -3981,6 +4001,7 @@ function expand_struct_def(ctx, ex, docs)
                     global_struct_name
                     newtype_var
                  ]
+                [K"latestworld"]
                 # Default constructors
                 if isempty(inner_defs)
                     default_inner_constructors(ctx, ex, global_struct_name,

src/eval.jl

@@ -313,6 +313,7 @@ function to_lowered_expr(mod, ex, ssa_offset=0)
                k == K"constdecl" ? :const      :
                k == K"leave"     ? :leave      :
                k == K"isdefined" ? :isdefined  :
+               k == K"latestworld"       ? :latestworld       :
                k == K"globaldecl"        ? :globaldecl        :
                k == K"pop_exception"     ? :pop_exception     :
                k == K"captured_local"    ? :captured_local    :

src/kinds.jl

@@ -111,6 +111,8 @@ function _register_kinds()
             # A local variable captured into a global method. Contains the
             # `index` of the associated `Box` in the rewrite list.
             "captured_local"
+            # Causes the linearization pass to conditionally emit a world age increment
+            "latestworld_if_toplevel"
         "END_LOWERING_KINDS"
 
         # The following kinds are emitted by lowering and used in Julia's untyped IR
@@ -147,6 +149,8 @@ function _register_kinds()
             "new_opaque_closure"
             # Wrapper for the lambda of around opaque closure methods
             "opaque_closure_method"
+            # World age increment
+            "latestworld"
         "END_IR_KINDS"
     ])
 end

src/linear_ir.jl

@@ -819,12 +819,19 @@ function compile(ctx::LinearIRContext, ex, needs_value, in_tail_pos)
         end
     elseif k == K"gc_preserve_begin"
         makenode(ctx, ex, k, compile_args(ctx, children(ex)))
-    elseif k == K"gc_preserve_end" || k == K"global"
+    elseif k == K"gc_preserve_end"
         if needs_value
             throw(LoweringError(ex, "misplaced kind $k in value position"))
         end
         emit(ctx, ex)
         nothing
+    elseif  k == K"global"
+        if needs_value
+            throw(LoweringError(ex, "misplaced kind $k in value position"))
+        end
+        emit(ctx, ex)
+        ctx.is_toplevel_thunk && emit(ctx, makenode(ctx, ex, K"latestworld"))
+        nothing
     elseif k == K"meta"
         emit(ctx, ex)
         if needs_value
@@ -881,6 +888,11 @@ function compile(ctx::LinearIRContext, ex, needs_value, in_tail_pos)
             emit(ctx, @ast ctx ex [K"=" rr ex[2]])
             emit(ctx, @ast ctx ex [K"globaldecl" ex[1] rr])
         end
+        ctx.is_toplevel_thunk && emit(ctx, makenode(ctx, ex, K"latestworld"))
+    elseif k == K"latestworld"
+        emit(ctx, ex)
+    elseif k == K"latestworld_if_toplevel"
+        ctx.is_toplevel_thunk && emit(ctx, makeleaf(ctx, ex, K"latestworld"))
     else
         throw(LoweringError(ex, "Invalid syntax; $(repr(k))"))
     end

src/syntax_graph.jl

@@ -431,6 +431,7 @@ function _value_string(ex)
           k == K"Symbol"      ? ":$(ex.name_val)" :
           k == K"globalref"   ? "$(ex.mod).$(ex.name_val)" :
           k == K"slot"        ? "slot" :
+          k == K"latestworld" ? "(latestworld)" :
           k == K"static_parameter" ? "static_parameter" :
           k == K"symbolic_label" ? "label:$(ex.name_val)" :
           k == K"symbolic_goto" ? "goto:$(ex.name_val)" :