[CIR][Github][CI] Add clangir upstream rebase workflow

Author: xlauko

.github/workflows/clang-cir-rebase.yml

@@ -0,0 +1,49 @@
+name: Clang CIR Rebase
+
+on: workflow_dispatch
+
+permissions:
+  contents: write
+
+env:
+  UPSTREAM_REPO: https://github.com/llvm/llvm-project.git
+  TARGET_BRANCH: rebased-${{ github.head_ref || github.ref_name }}
+
+jobs:
+  rebase:
+    name: Rebase Clang CIR onto LLVM upstream
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          token: ${{ secrets.WORKFLOW_TOKEN }}
+
+      - name: Set up Git user
+        run: |
+          git config --global user.name "github-actions[bot]"
+          git config --global user.email "github-actions[bot]@users.noreply.github.com"
+
+      - name: Add upstream remote
+        run: |
+          git remote add upstream $UPSTREAM_REPO
+          git fetch upstream main
+
+      - name: Rebase CIR branch onto LLVM upstream
+        run: |
+          sh ./.github/workflows/rebase-clangir-onto-llvm-upstream.sh $TARGET_BRANCH
+
+      - name: Push rebase branch ${{ github.env.TARGET_BRANCH }}
+        run: |
+          git push --set-upstream origin ${{ github.env.TARGET_BRANCH }}
+
+  test-clang-cir:
+    name: Test Clang CIR
+    needs: rebase
+    uses: ./.github/workflows/llvm-project-tests.yml
+    with:
+      build_target: check-clang-cir
+      projects: clang;mlir
+      extra_cmake_args: -DCLANG_ENABLE_CIR=ON
+      repo_ref: ${{ github.env.TARGET_BRANCH }}

.github/workflows/llvm-project-tests.yml

@@ -51,6 +51,12 @@ on:
         type: string
         default: '3.11'
 
+      # Optional reference to the branch being checked out.
+      # Uses the current branch if not specified.
+      repo_ref:
+        required: false
+        type: string
+
 concurrency:
   # Skip intermediate builds: always.
   # Cancel intermediate builds: only if it is a pull request build.
@@ -93,6 +99,7 @@ jobs:
       # clean: false.
       - uses: actions/checkout@v4
         with:
+          ref: ${{ inputs.repo_ref || github.ref }}
           fetch-depth: 250
       - name: Setup ccache
         uses: hendrikmuhs/ccache-action@v1

.github/workflows/rebase-clangir-onto-llvm-upstream.sh

@@ -0,0 +1,98 @@
+#!/bin/bash
+
+set -e
+
+GREEN='\033[0;32m'
+RED='\033[0;31m'
+YELLOW='\033[1;33m'
+NC='\033[0m'
+
+REBASE_BRANCH=rebased-clangir-onto-llvm-upstream
+TARGET_BRANCH=$1
+
+log() { printf "%b[%s]%b %s\n" "$1" "$2" "$NC" "$3"; }
+log_info() { log "$GREEN" "INFO" "$1"; }
+log_warn() { log "$YELLOW" "WARN" "$1"; }
+log_error() { log "$RED" "ERROR" "$1" >&2; }
+
+error_exit() {
+    log_error "$1"
+    exit 1
+}
+
+is_rebasing() {
+    git rev-parse --git-path rebase-merge >/dev/null 2>&1 ||
+        git rev-parse --git-path rebase-apply >/dev/null 2>&1
+}
+
+git rev-parse --is-inside-work-tree >/dev/null 2>&1 ||
+    error_exit "Not in a Git repository."
+
+git remote get-url upstream >/dev/null 2>&1 ||
+    error_exit "Upstream remote not found."
+
+log_info "Fetching latest changes from upstream..."
+
+git fetch upstream main ||
+    error_exit "Failed to fetch from upstream."
+
+REBASING_CIR_BRANCH=$(git branch --show-current)
+
+if [ -z "$COMMON_ANCESTOR" ]; then
+    COMMON_ANCESTOR=$(git merge-base upstream/main "$REBASING_CIR_BRANCH") ||
+        error_exit "Could not find common ancestor."
+    log_info "Common ancestor commit: $COMMON_ANCESTOR"
+fi
+
+if [ "$REBASING_CIR_BRANCH" != "$REBASE_BRANCH" ]; then
+    if git rev-parse --verify "$REBASE_BRANCH" >/dev/null 2>&1; then
+        git branch -D "$REBASE_BRANCH" >/dev/null 2>&1 ||
+            log_warn "Failed to delete existing branch $REBASE_BRANCH."
+    fi
+
+    git switch -c "$REBASE_BRANCH" "$COMMON_ANCESTOR" ||
+        error_exit "Failed to create branch $REBASE_BRANCH."
+fi
+
+#
+# Rebase upstream changes
+#
+log_info "Processing upstream commits..."
+git rebase upstream/main ||
+    error_exit "Failed to rebase."
+
+#
+# Reverse upstream CIR commits
+#
+log_info "Reverting upstream CIR commits..."
+git log --grep="\[CIR\]" --format="%H %s" "$COMMON_ANCESTOR..upstream/main" | while read -r HASH MESSAGE; do
+    log_info "Reverting: $MESSAGE"
+
+    if ! git revert --no-edit "$HASH"; then
+        error_exit "Failed to revert commit $HASH"
+    fi
+done
+
+#
+# Rebase CIR commits
+#
+log_info "Rebasing CIR incubator commits..."
+
+if [ -z "$TARGET_BRANCH" ]; then
+    log_error "Target branch not specified."
+    exit 1
+fi
+
+if git rev-parse --verify "$TARGET_BRANCH" >/dev/null 2>&1; then
+    git branch -D "$TARGET_BRANCH" >/dev/null 2>&1 ||
+        error_exit "Failed to delete existing branch $TARGET_BRANCH."
+fi
+
+git switch "$REBASING_CIR_BRANCH" ||
+    error_exit "Failed to switch to $REBASING_CIR_BRANCH."
+git checkout -b "$TARGET_BRANCH" ||
+    error_exit "Failed to checkout $TARGET_BRANCH."
+git rebase "$REBASE_BRANCH" "$TARGET_BRANCH" ||
+    error_exit "Failed to rebase."
+
+log_info "Rebase completed successfully!"