Kernel UT: Enable preprocessor when running cflow in callgraph.py (#530)

* Add INCLUDE_DIR to the commandline call to cflow in callgraph.py

This removes dependent functions from the list when they are disabled in the FreeRTOS config.

* Add argparse to callgraph.py so that no output file is created on failure.

FreeRTOS/Test/CMock/testdir.mk

@@ -120,7 +120,7 @@ $(MOCK_HDR_LIST) $(MOCK_SRC_LIST) : $(PROJECT_DIR)/$(PROJECT).yml $(MOCK_FILES_F
 # Generate callgraph for coverage filtering
 $(PROJ_DIR)/callgraph.json : $(PROJ_SRC_LIST)
     mkdir -p $(PROJ_DIR)
-    python3 $(UT_ROOT_DIR)/tools/callgraph.py $^ > $@
+    python3 $(UT_ROOT_DIR)/tools/callgraph.py --out $@ $^
 
 # preprocess proj files to expand macros for coverage
 $(PROJ_DIR)/%.i : $(KERNEL_DIR)/%.c

FreeRTOS/Test/CMock/tools/callgraph.py

@@ -24,6 +24,7 @@
 # https://www.FreeRTOS.org
 # https://github.com/FreeRTOS
 ###############################################################################
+import argparse
 import json
 import os
 import re
@@ -31,12 +32,36 @@ import subprocess
 import sys
 from typing import Dict, List, Set
 
-target_files = sys.argv[1:]
+arg_parser = argparse.ArgumentParser(
+    description="Parse each input .c file and generate a callgraph.json containing"
+    " a map from each function name to a list of the other functions which the first"
+    " function calls."
+)
+
+arg_parser.add_argument(
+    "-o", "--out", required=True, help="Output callgraph.json file path."
+)
+
+arg_parser.add_argument("in_files", nargs="+", help="Input .c files to be parsed.")
+args = arg_parser.parse_args()
+
+if vars(args)["out"] and not os.path.isdir(os.path.dirname(vars(args)["out"])):
+    print("The output directory does not exist.", file=sys.stderr)
+    sys.exit(1)
+
+target_files = args.in_files
 
 for f in target_files:
     if not os.path.isfile(f):
         print("ERROR: Input file {} does not exist.".format(f))
-        exit(1)
+        sys.exit(1)
+
+includes = ""
+# Get INCLUDE_DIR from envrionment
+if "INCLUDE_DIR" in os.environ:
+    includes = os.environ["INCLUDE_DIR"]
+else:
+    print("WARNING: INCLUDE_DIR variable was not found in the envrionment.")
 
 ret = subprocess.run(
     [
@@ -46,6 +71,7 @@ ret = subprocess.run(
         "--omit-arguments",
         "--omit-symbol-names",
         "--all",
+        includes,
     ]
     + target_files,
     capture_output=True,
@@ -103,4 +129,5 @@ for key in callmap:
     temp_list = list(callmap[key])
     callmap_list[key] = temp_list
 
-print(json.dumps(callmap_list))
+with open(args.out, "w") as outfile:
+    json.dump(callmap_list, outfile)