From 00bbb8e08194015e41422ddbcd1b84b046908551 Mon Sep 17 00:00:00 2001
From: Axel Naumann <Axel.Naumann@cern.ch>
Date: Mon, 9 Aug 2021 17:13:55 +0200
Subject: [PATCH] Windows: always emit definitions of JITed "weak" variables

Fixes test failures (crashes) in
    projectroot.test.test_stressiterators_interpreted
    projectroot.roottest.cling.dict.roottest_cling_dict_assertTmpltDefArgCtor
    projectroot.test.test_stresshistogram_interpreted
    projectroot.roottest.root.meta.roottest_root_meta_runnamespace_auto
---
 lib/Interpreter/BackendPasses.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/lib/Interpreter/BackendPasses.cpp b/lib/Interpreter/BackendPasses.cpp
index f2eba89e..2c3cdd9a 100644
--- a/lib/Interpreter/BackendPasses.cpp
+++ b/lib/Interpreter/BackendPasses.cpp
@@ -140,9 +140,14 @@ namespace {
 
       // Find the symbol in JIT or shared libraries.
       if (m_JIT.getSymbolAddress(GV.getName(), /*AlsoInProcess*/ true)) {
+#if !defined(_WIN32)
+        // Heuristically, Windows cannot handle cross-library variables; they
+        // must be library-local.
         if (auto *Var = dyn_cast<GlobalVariable>(&GV)) {
           Var->setInitializer(nullptr); // make this a declaration
-        } else if (auto *Func = dyn_cast<Function>(&GV)) {
+        } else
+#endif
+        if (auto *Func = dyn_cast<Function>(&GV)) {
           Func->deleteBody(); // make this a declaration
         } else {
           llvm_unreachable("What is this?");