From 2b402022a110613003dda6ebb3067a84db5f1cbb Mon Sep 17 00:00:00 2001
From: Ben Hekster <dev@hekster.org>
Date: Sat, 16 Jul 2022 00:14:06 -0700
Subject: [PATCH] Explicitly mark global variable definition as having
 'undefined' value

---
 Chapter07/tinylang/lib/CodeGen/CGModule.cpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/Chapter07/tinylang/lib/CodeGen/CGModule.cpp b/Chapter07/tinylang/lib/CodeGen/CGModule.cpp
index 9963d2c..04f7c99 100644
--- a/Chapter07/tinylang/lib/CodeGen/CGModule.cpp
+++ b/Chapter07/tinylang/lib/CodeGen/CGModule.cpp
@@ -97,10 +97,12 @@ void CGModule::run(ModuleDeclaration *Mod) {
     if (auto *Var =
             llvm::dyn_cast<VariableDeclaration>(Decl)) {
       // Create global variables
+      llvm::Type *T = convertType(Var->getType());
       llvm::GlobalVariable *V = new llvm::GlobalVariable(
-          *M, convertType(Var->getType()),
+          *M, T,
           /*isConstant=*/false,
-          llvm::GlobalValue::PrivateLinkage, nullptr,
+          llvm::GlobalValue::PrivateLinkage,
+          llvm::UndefValue::get(T),
           mangleName(Var));
       Globals[Var] = V;
       if (CGDebugInfo *Dbg = getDbgInfo())