Clang-Tidy Cache

Use ccache in the clang-tidy CI. This allows us to skip clang-tidy checks on
files that are not changed as reported by ccache.

.github/workflows/clang_tidy.yml

@@ -16,28 +16,26 @@ jobs:
     - name: install dependencies
       run: |
         .github/workflows/dependencies/clang14.sh
-    - name: build WarpX using clang-tidy
+    - name: set up cache
+      uses: actions/cache@v3
+      with:
+        path: ~/.cache/ccache
+        key: ccache-clang-tidy-${{ github.job }}-git-${{ github.sha }}
+        restore-keys: |
+             ccache-clang-tidy-${{ github.job }}-git-
+    - name: build WarpX & run clang-tidy
       run: |
-
+        export CCACHE_COMPRESS=1
+        export CCACHE_COMPRESSLEVEL=10
+        export CCACHE_MAXSIZE=300M
+        export CCACHE_EXTRAFILES=${{ github.workspace }}/.clang-tidy
+        export CCACHE_LOGFILE=${{ github.workspace }}/ccache.log.txt
+        ccache -z
 
         export CXX=$(which clang++)
         export CC=$(which clang)
 
-        # The following wrapper ensures that only source files
-        # in WarpX/Source/* are actually processed by clang-tidy
-        #_______________________________
-        cat > clang_tidy_wrapper << EOF
-        #!/bin/bash
-        REGEX="[a-z_A-Z0-9\/]*WarpX\/Source[a-z_A-Z0-9\/]+.cpp"
-        if [[ \$4 =~ \$REGEX ]];then
-          clang-tidy \$@
-        fi
-        EOF
-        chmod +x clang_tidy_wrapper
-        #_____________________________________
-
         cmake -S . -B build_clang_tidy \
-          -DCMAKE_CXX_CLANG_TIDY="$PWD/clang_tidy_wrapper;--system-headers=0;--config-file=$PWD/.clang-tidy" \
           -DCMAKE_VERBOSE_MAKEFILE=ON  \
           -DWarpX_DIMS="1;2;3;RZ"      \
           -DWarpX_MPI=ON               \
@@ -46,9 +44,15 @@ jobs:
           -DWarpX_QED=ON               \
           -DWarpX_QED_TABLE_GEN=ON     \
           -DWarpX_OPENPMD=ON           \
-          -DWarpX_PRECISION=SINGLE
+          -DWarpX_PRECISION=SINGLE     \
+          -DCMAKE_CXX_COMPILER_LAUNCHER=ccache
+
+        cmake --build build_clang_tidy -j 2
 
-        cmake --build build_clang_tidy -j 2 2> build_clang_tidy/clang-tidy.log
+        ${{github.workspace}}/.github/workflows/source/makeMakefileForClangTidy.py --input ${{github.workspace}}/ccache.log.txt
+        make -j2 -f clang-tidy-ccache-misses.mak \
+            CLANG_TIDY=clang-tidy \
+            CLANG_TIDY_ARGS="--config-file=${{github.workspace}}/.clang-tidy --warnings-as-errors=*"
 
-        cat build_clang_tidy/clang-tidy.log
-        if [[ $(wc -m <build_clang_tidy/clang-tidy.log) -gt 1 ]]; then exit 1; fi
+        ccache -s
+        du -hs ~/.cache/ccache

.github/workflows/source/makeMakefileForClangTidy.py

@@ -0,0 +1,61 @@
+#!/usr/bin/env python3
+
+"""
+A script processing ccache log file to make Make file for Clang-Tidy
+
+This generates a makefile for clang-tidying ccache-cache-missing files. This
+could be used to speed up clang-tidy in CIs.
+"""
+
+import argparse, re, sys
+
+def makeMakefileForClangTidy(argv):
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--input",
+                        help="Ccache log file",
+                        default="ccache.log.txt")
+    parser.add_argument("--identifier",
+                        help="Unique identifier for finding compilation line in the log file",
+                        default="WarpX/Source")
+    # We assume Src/Base can be used as an identifier to distinguish amrex code
+    # from cmake's temporary files like build/CMakeFiles/CMakeScratch/TryCompile-hw3x4m/test_mpi.cpp
+    parser.add_argument("--output",
+                        help="Make file for clang-tidy",
+                        default="clang-tidy-ccache-misses.mak")
+    args = parser.parse_args()
+
+    fin = open(args.input, "r")
+    fout = open(args.output, "w")
+
+    fout.write("CLANG_TIDY ?= clang-tidy\n")
+    fout.write("override CLANG_TIDY_ARGS += --extra-arg=-Wno-unknown-warning-option --extra-arg-before=--driver-mode=g++\n")
+    fout.write("\n")
+
+    fout.write(".SECONDEXPANSION:\n")
+    fout.write("clang-tidy: $$(all_targets)\n")
+    fout.write("\t@echo SUCCESS\n\n")
+
+    exe_re = re.compile(r" Executing .*? (-.*{}.*) -c .* -o .* (\S*)".format(args.identifier))
+
+    count = 0
+    for line in fin.readlines():
+        ret_exe_re = exe_re.search(line)
+        if (ret_exe_re):
+            fout.write("target_{}: {}\n".format(count, ret_exe_re.group(2)))
+            fout.write("\t$(CLANG_TIDY) $(CLANG_TIDY_ARGS) $< -- {}\n".format
+                       (ret_exe_re.group(1)))
+            fout.write("\ttouch target_{}\n\n".format(count))
+            count = count + 1
+
+    fout.write("all_targets =")
+    for i in range(count):
+        fout.write(" target_{}".format(i))
+    fout.write("\n\n")
+
+    fout.write("clean:\n\t$(RM) $(all_targets)\n\n")
+
+    fout.close()
+    fin.close()
+
+if __name__ == "__main__":
+    makeMakefileForClangTidy(sys.argv)