diff --git a/utils/build-presets.ini b/utils/build-presets.ini
index 7260a7d4c8eb6..2dfbd71ad780a 100644
--- a/utils/build-presets.ini
+++ b/utils/build-presets.ini
@@ -1374,6 +1374,9 @@ xctest
 swift-install-components=autolink-driver;compiler;clang-resource-dir-symlink;libexec;stdlib;swift-remote-mirror;sdk-overlay;static-mirror-lib;toolchain-tools;license;sourcekit-inproc
 llvm-install-components=llvm-ar;llvm-ranlib;llvm-cov;llvm-profdata;llvm-objdump;llvm-objcopy;llvm-symbolizer;IndexStore;clang;clang-resource-headers;builtins;runtimes;clangd;libclang;lld;LTO;clang-features-file
 
+extra-llvm-cmake-options=
+  -DLLVM_ENABLE_LIBXML2=OFF
+
 install-foundation
 install-libdispatch
 install-llbuild
diff --git a/utils/build-script-impl b/utils/build-script-impl
index 3ebf7b45a4541..9f3c444de9dc4 100755
--- a/utils/build-script-impl
+++ b/utils/build-script-impl
@@ -2126,6 +2126,33 @@ for host in "${ALL_HOSTS[@]}"; do
                     DOTEST_EXTRA="${DOTEST_EXTRA} -Xlinker -rpath -Xlinker ${FOUNDATION_BUILD_DIR}/lib"
                 fi
 
+                if [[ ! "${SKIP_BUILD_LIBXML2}" ]]; then
+                  # Note: This is wrong when cross-compiling. LLDB is part of
+                  # the toolchain while the built libxml2 is built for the
+                  # runtime environment for use in FoundationXML.
+                  # Build-Script does not separate the toolchain and runtime
+                  # build, so this is already broken.
+                  BASE_INSTALL_DIR="$(get_host_install_destdir ${host})"
+                  LIBXML2_HEADERS="${BASE_INSTALL_DIR}/usr/include/libxml2"
+                  LIBXML2_LIBRARY="${BASE_INSTALL_DIR}/usr/lib/libxml2.a"
+
+                  if [[ -z "${DRY_RUN}" && ! -d "${LIBXML2_HEADERS}" ]]; then
+                      echo "Error: '${LIBXML2_HEADERS}' does not exist" 1>&2
+                      exit 1
+                  fi
+
+                  if [[ -z "${DRY_RUN}" && ! -e "${LIBXML2_LIBRARY}" ]]; then
+                      echo "Error: '${LIBXML2_LIBRARY}' does not exist" 1>&2
+                      exit 1
+                  fi
+
+                  cmake_options+=(
+                    -DLIBXML2_INCLUDE_DIR:PATH="${LIBXML2_HEADERS}"
+                    -DLIBXML2_LIBRARY:PATH="${LIBXML2_LIBRARY}"
+                    -DLIBXML2_DEFINITIONS="-DLIBXML_STATIC"
+                  )
+                fi
+
                 # Watchpoint testing is currently disabled: see rdar://38566150.
                 LLDB_TEST_CATEGORIES="--skip-category=watchpoint"