From 227fa7b5e6f4b46bfb73b1f2861084a3e15422b2 Mon Sep 17 00:00:00 2001
From: Cody Tapscott <84105208+topolarity@users.noreply.github.com>
Date: Wed, 24 Apr 2024 16:18:22 -0400
Subject: [PATCH] effects: annotate `nameof(::Module)` +
 `parentmodule(::Module)` for constant folding (#54223)

These effects can be important for us to statically resolve
Module-handling logic that, e.g., inspects a loaded list of modules
looking for a particular name.

Co-authored-by: @gbaraldi

Co-authored-by: gbaraldi <baraldigabriel@gmail.com>
Co-authored-by: Cody Tapscott <topolarity@users.noreply.github.com>
---
 base/essentials.jl | 28 +++++++++++++++-------------
 base/reflection.jl |  4 +++-
 2 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/base/essentials.jl b/base/essentials.jl
index fdc66e94d1a00..4e8a22fd229a9 100644
--- a/base/essentials.jl
+++ b/base/essentials.jl
@@ -180,22 +180,11 @@ macro isdefined(s::Symbol)
     return Expr(:escape, Expr(:isdefined, s))
 end
 
-"""
-    nameof(m::Module) -> Symbol
-
-Get the name of a `Module` as a [`Symbol`](@ref).
-
-# Examples
-```jldoctest
-julia> nameof(Base.Broadcast)
-:Broadcast
-```
-"""
-nameof(m::Module) = ccall(:jl_module_name, Ref{Symbol}, (Any,), m)
+_nameof(m::Module) = ccall(:jl_module_name, Ref{Symbol}, (Any,), m)
 
 function _is_internal(__module__)
     if ccall(:jl_base_relative_to, Any, (Any,), __module__)::Module === Core.Compiler ||
-       nameof(__module__) === :Base
+       _nameof(__module__) === :Base
         return true
     end
     return false
@@ -375,6 +364,19 @@ getindex(A::GenericMemory, i::Int) = (@_noub_if_noinbounds_meta;
     memoryrefget(memoryref(memoryref(A), i, @_boundscheck), default_access_order(A), false))
 getindex(A::GenericMemoryRef) = memoryrefget(A, default_access_order(A), @_boundscheck)
 
+"""
+    nameof(m::Module) -> Symbol
+
+Get the name of a `Module` as a [`Symbol`](@ref).
+
+# Examples
+```jldoctest
+julia> nameof(Base.Broadcast)
+:Broadcast
+```
+"""
+nameof(m::Module) = (@_total_meta; ccall(:jl_module_name, Ref{Symbol}, (Any,), m))
+
 function iterate end
 
 """
diff --git a/base/reflection.jl b/base/reflection.jl
index 2df713a531fae..f27da6d4df32e 100644
--- a/base/reflection.jl
+++ b/base/reflection.jl
@@ -18,7 +18,7 @@ julia> parentmodule(Base.Broadcast)
 Base
 ```
 """
-parentmodule(m::Module) = ccall(:jl_module_parent, Ref{Module}, (Any,), m)
+parentmodule(m::Module) = (@_total_meta; ccall(:jl_module_parent, Ref{Module}, (Any,), m))
 
 is_root_module(m::Module) = parentmodule(m) === m || (isdefined(Main, :Base) && m === Main.Base)
 
@@ -30,6 +30,7 @@ parent modules of `m` which is either a registered root module or which is its
 own parent module.
 """
 function moduleroot(m::Module)
+    @_total_meta
     while true
         is_root_module(m) && return m
         p = parentmodule(m)
@@ -63,6 +64,7 @@ julia> fullname(Main)
 ```
 """
 function fullname(m::Module)
+    @_total_meta
     mn = nameof(m)
     if m === Main || m === Base || m === Core
         return (mn,)