Allow cloning llvm and rust separately

Author: topjohnwu

common.sh

@@ -49,7 +49,7 @@ git_clone_sha() {
   local dir=${1##*/}
   mkdir "$dir"
   cd "$dir"
-  git init
+  git init -q
   git remote add origin $1
   git fetch --depth 1 origin $2
   git reset --hard FETCH_HEAD
@@ -60,17 +60,13 @@ git_clone_branch() {
   git clone --single-branch --depth 1 --branch $2 $1
 }
 
-clone() {
-  git_clone_branch https://github.com/rust-lang/rust $RUST_VERSION
-  cd rust
-  for p in ../patches/*.patch; do
-    patch -p1 < $p
-  done
-  # Skip rust llvm
-  sed 's:\[submodule "src/llvm-project"\]:&\n\tupdate = none:' .gitmodules > .gitmodules.p
+skip_submodule() {
+  sed "s:.*submodule.*$1.*:&\n\tupdate = none:" .gitmodules > .gitmodules.p
   mv .gitmodules.p .gitmodules
-  git submodule update --init --depth=1
-  cd ../
+}
+
+clone_llvm() {
+  rm -rf llvm-project llvm_android toolchain-utils
 
   git_clone_sha https://android.googlesource.com/toolchain/llvm-project $LLVM_VERSION
   git_clone_sha https://android.googlesource.com/toolchain/llvm_android $LLVM_ANDROID_VERSION
@@ -81,10 +77,33 @@ clone() {
     --svn_version $LLVM_SVN \
     --patch_metadata_file llvm_android/patches/PATCHES.json \
     --src_path llvm-project
+}
 
-  # Move the NDK LLVM into Rust's source
-  rm -rf rust/src/llvm-project
-  mv llvm-project rust/src/llvm-project
+clone_rust() {
+  rm -rf rust
+
+  git_clone_branch https://github.com/rust-lang/rust $RUST_VERSION
+  cd rust
+
+  # Skip unused submodules
+  skip_submodule llvm-project
+  skip_submodule enzyme
+  skip_submodule gcc
+  skip_submodule doc
+
+  # Clone submodules
+  git submodule update --init --depth=1
+
+  # Apply patches
+  for p in ../patches/*.patch; do
+    patch -p1 < $p
+  done
+
+  # Link NDK LLVM into Rust's source
+  rm -rf src/llvm-project
+  ln -s ../../llvm-project src/llvm-project
+
+  cd ../
 }
 
 update_dir() {
@@ -129,8 +148,14 @@ dist() {
 run_cmd() {
   case $1 in
     clone)
-      rm -rf rust llvm-project llvm_android toolchain-utils
-      clone
+      clone_llvm
+      clone_rust
+      ;;
+    clone-llvm)
+      clone_llvm
+      ;;
+    clone-rust)
+      clone_rust
       ;;
     build)
       rm -rf rust-out