diff --git a/Formula/llvm/libc++abi.rb b/Formula/llvm/libc++abi.rb
index 347532bd..1ad94dbe 100644
--- a/Formula/llvm/libc++abi.rb
+++ b/Formula/llvm/libc++abi.rb
@@ -1,8 +1,8 @@
 class Libcxxabi < Formula
   desc "C++ Standard Library Support"
   homepage "https://libcxxabi.llvm.org/"
-  url "https://github.com/llvm/llvm-project/releases/download/llvmorg-17.0.2/llvm-project-17.0.2.src.tar.xz"
-  sha256 "351562b14d42fcefcbf00cc1f327680a1062bbbf67a1e1ca6acb64c473b06394"
+  url "https://github.com/llvm/llvm-project/releases/download/llvmorg-18.1.2/llvm-project-18.1.2.src.tar.xz"
+  sha256 "51073febd91d1f2c3b411d022695744bda322647e76e0b4eb1918229210c48d5"
   license "Apache-2.0" => { with: "LLVM-exception" }
 
   bottle do
@@ -12,9 +12,11 @@ class Libcxxabi < Formula
 
   depends_on "cmake" => :build
 
+  depends_on "paperchalice/private/libunwind"
+
   def install
     cmake_args = std_cmake_args+ %w[
-      -D LLVM_ENABLE_RUNTIMES=libcxx;libcxxabi
+      -D LLVM_ENABLE_RUNTIMES=libcxx;libcxxabi;libunwind
 
       -S runtimes
       -B build