Update formatting script.

Since we're based on llvm/main now, our previous formatting script won't
work anymore. Let's try formatting any changes since ykjit/main instead.

Author: ptersilie

.buildbot.sh

@@ -2,11 +2,6 @@
 
 set -e
 
-# Buildbot will have done a shallow clone, but the formatting step requires
-# both full git history, and a complete set of upstream llvm release tags.
-git fetch --unshallow
-git fetch --tags https://github.com/llvm/llvm-project
-
 INST_DIR=`pwd`/inst
 
 mkdir -p build
@@ -22,6 +17,7 @@ make -j `nproc` install
 # clang-format any new files that we've introduced ourselves.
 cd ..
 PATH=${INST_DIR}/bin:${PATH}
+git fetch origin main:refs/remotes/origin/main
 sh yk_format_new_files.sh
 git diff --exit-code
 

yk_format_new_files.sh

@@ -4,8 +4,4 @@
 
 set -e
 
-# The LLVM version tag we are forked from.
-FORKED_LLVM_VERSION=`git describe --abbrev=0 --match 'llvmorg-*'`
-
-git diff --name-only --diff-filter=A ${FORKED_LLVM_VERSION} \
-    `git branch --show-current` | egrep '\.(cpp|h)$' | xargs clang-format -i
+clang/tools/clang-format/git-clang-format origin/main