xen/misra: xen-analysis.py: fix parallel analysis Cppcheck errors

Currently Cppcheck has a limitation that prevents to use make with
parallel build and have a parallel Cppcheck invocation on each
translation unit (the .c files), because of spurious internal errors.

The issue comes from the fact that when using the build directory,
Cppcheck saves temporary files as <filename>.c.<many-extensions>, but
this doesn't work well when files with the same name are being
analysed at the same time, leading to race conditions.

Fix the issue creating, under the build directory, the same directory
structure of the file being analysed to avoid any clash.

Fixes: 02b26c02c7 ("xen/scripts: add cppcheck tool to the xen-analysis.py script")
Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

xen/scripts/xen_analysis/cppcheck_analysis.py

@@ -139,7 +139,6 @@ def generate_cppcheck_deps():
     # Compiler defines are in compiler-def.h which is included in config.h
     #
     cppcheck_flags="""
---cppcheck-build-dir={}/{}
  --max-ctu-depth=10
  --enable=style,information,missingInclude
  --template=\'{{file}}({{line}},{{column}}):{{id}}:{{severity}}:{{message}}\'
@@ -150,8 +149,7 @@ def generate_cppcheck_deps():
  --suppress='unusedStructMember:*'
  --include={}/include/xen/config.h
  -DCPPCHECK
-""".format(settings.outdir, CPPCHECK_BUILD_DIR, settings.xen_dir,
-           settings.outdir, settings.xen_dir)
+""".format(settings.xen_dir, settings.outdir, settings.xen_dir)
 
     invoke_cppcheck = utils.invoke_command(
             "{} --version".format(settings.cppcheck_binpath),
@@ -204,9 +202,9 @@ def generate_cppcheck_deps():
 
     cppcheck_cc_flags = """--compiler={} --cppcheck-cmd={} {}
  --cppcheck-plat={}/cppcheck-plat --ignore-path=tools/
- --ignore-path=arch/x86/efi/check.c
+ --ignore-path=arch/x86/efi/check.c --build-dir={}/{}
 """.format(xen_cc, settings.cppcheck_binpath, cppcheck_flags,
-           settings.tools_dir)
+           settings.tools_dir, settings.outdir, CPPCHECK_BUILD_DIR)
 
     if settings.cppcheck_html:
         cppcheck_cc_flags = cppcheck_cc_flags + " --cppcheck-html"

xen/tools/cppcheck-cc.sh

@@ -24,6 +24,7 @@ Options:
 EOF
 }
 
+BUILD_DIR=""
 CC_FILE=""
 COMPILER=""
 CPPCHECK_HTML="n"
@@ -66,6 +67,10 @@ do
             help
             exit 0
             ;;
+        --build-dir=*)
+            BUILD_DIR="${OPTION#*=}"
+            sm_tool_args="n"
+            ;;
         --compiler=*)
             COMPILER="${OPTION#*=}"
             sm_tool_args="n"
@@ -107,6 +112,12 @@ then
     exit 1
 fi
 
+if [ "${BUILD_DIR}" = "" ]
+then
+    echo "--build-dir arg is mandatory."
+    exit 1
+fi
+
 function create_jcd() {
     local line="${1}"
     local arg_num=0
@@ -199,13 +210,18 @@ then
             exit 1
         fi
 
+        # Generate build directory for the analysed file
+        cppcheck_build_dir="${BUILD_DIR}/${OBJTREE_PATH}"
+        mkdir -p "${cppcheck_build_dir}"
+
         # Shellcheck complains about missing quotes on CPPCHECK_TOOL_ARGS, but
         # they can't be used here
         # shellcheck disable=SC2086
         ${CPPCHECK_TOOL} ${CPPCHECK_TOOL_ARGS} \
             --project="${JDB_FILE}" \
             --output-file="${out_file}" \
-            --platform="${platform}"
+            --platform="${platform}" \
+            --cppcheck-build-dir=${cppcheck_build_dir}
 
         if [ "${CPPCHECK_HTML}" = "y" ]
         then
@@ -216,6 +232,7 @@ then
                 --project="${JDB_FILE}" \
                 --output-file="${out_file%.txt}.xml" \
                 --platform="${platform}" \
+                --cppcheck-build-dir=${cppcheck_build_dir} \
                 -q \
                 --xml
         fi