Mark jl_world_counter as an inactive integral global (#3208)

Julia's world age counter is an external `i64` global with no
initializer, so Enzyme could neither deduce its inner type nor
create a shadow for it, erroring with

  cannot compute with global variable that doesn't have marked
  shadow global
  @jl_world_counter = external local_unnamed_addr global i64

Seed its type as a pointer to integer data in type analysis, and
list it (along with the `ijl_` variant) among the known inactive
globals in activity analysis.


Claude-Session: https://claude.ai/code/session_01JS9YgwAvq8YuPtRgkauuMu

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

enzyme/Enzyme/ActivityAnalysis.cpp

diff --git a/enzyme/Enzyme/ActivityAnalysis.cpp b/enzyme/Enzyme/ActivityAnalysis.cpp
index 0075d27..8299fd6 100644
--- a/enzyme/Enzyme/ActivityAnalysis.cpp
+++ b/enzyme/Enzyme/ActivityAnalysis.cpp
@@ -117,6 +117,8 @@
 static const StringSet<> InactiveGlobals = {
     "small_typeof",
     "jl_small_typeof",
+    "jl_world_counter",
+    "ijl_world_counter",
     "ompi_request_null",
     "ompi_mpi_double",
     "ompi_mpi_comm_world",

enzyme/Enzyme/TypeAnalysis/TypeAnalysis.cpp

diff --git a/enzyme/Enzyme/TypeAnalysis/TypeAnalysis.cpp b/enzyme/Enzyme/TypeAnalysis/TypeAnalysis.cpp
index d9f02f0..c9dee61 100644
--- a/enzyme/Enzyme/TypeAnalysis/TypeAnalysis.cpp
+++ b/enzyme/Enzyme/TypeAnalysis/TypeAnalysis.cpp
@@ -886,6 +886,16 @@
       return;
     }
 
+    // from julia code, the world age counter is an integer
+    if (GV->getName() == "jl_world_counter" ||
+        GV->getName() == "ijl_world_counter") {
+      TypeTree T;
+      T.insert({-1}, BaseType::Pointer);
+      T.insert({-1, -1}, BaseType::Integer);
+      analysis[Val] = T;
+      return;
+    }
+
     if (startsWith(GV->getName(), getInstrProfCountersVarPrefix())) {
       TypeTree T;
       T.insert({-1}, BaseType::Pointer);