From 02c258079e6dafb0e279a4fc75297c37bb778df9 Mon Sep 17 00:00:00 2001
From: Roman Lebedev <lebedev.ri@gmail.com>
Date: Wed, 12 Mar 2025 16:14:43 +0300
Subject: [PATCH] CI: only clone/fetch the parts of LLVM monorepo that we need

This ends up being *much* faster, noticeably speeding up these jobs.
---
 .github/libcxx-setup.sh | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/.github/libcxx-setup.sh b/.github/libcxx-setup.sh
index 1bd972fb..d00e495e 100755
--- a/.github/libcxx-setup.sh
+++ b/.github/libcxx-setup.sh
@@ -3,7 +3,12 @@
 set -e
 
 # Checkout LLVM sources
-git clone --depth=1 --branch llvmorg-19.1.6 https://github.com/llvm/llvm-project.git llvm-project
+git clone --filter=blob:none --depth=1 --branch llvmorg-19.1.6 --no-checkout https://github.com/llvm/llvm-project.git llvm-project
+cd llvm-project
+git sparse-checkout set --cone
+git checkout llvmorg-19.1.6
+git sparse-checkout set cmake llvm/cmake runtimes libcxx libcxxabi
+cd ..
 
 ## Setup libc++ options
 if [ -z "$BUILD_32_BITS" ]; then
@@ -20,6 +25,9 @@ cmake -DCMAKE_C_COMPILER=${CC}                  \
       -DLLVM_USE_SANITIZER=${LIBCXX_SANITIZER}  \
       -DLLVM_BUILD_32_BITS=${BUILD_32_BITS}     \
       -DLIBCXXABI_USE_LLVM_UNWINDER=OFF         \
+      -DLLVM_INCLUDE_TESTS=OFF                  \
+      -DLIBCXX_INCLUDE_TESTS=OFF                \
+      -DLIBCXX_INCLUDE_BENCHMARKS=OFF           \
       -DLLVM_ENABLE_RUNTIMES='libcxx;libcxxabi' \
       -G "Unix Makefiles" \
       ../llvm-project/runtimes/