Added cppcheck static analysis tool

Fixed potential bugs in
1. STM32L475xx_main.c
- scanf overflow
- printf format
2. syssbrk.c
- pointer conversions when comparing address

NOTE: We must add cppcheck cmake variable before the cmake add_executable is defined

Author: coder137

Template/Minimal_Tools/CMakeLists.txt

@@ -64,6 +64,8 @@ else()
 
   message("Configuring ARM Project")
 
+  include(cmake/tool/cppcheck.cmake)
+
   # Cross Compiled project
   set(USER_PROJECT_TARGET "${PROJECT_NAME}.elf")
   add_executable(${USER_PROJECT_TARGET}

Template/Minimal_Tools/cmake/tool/cppcheck.cmake

@@ -0,0 +1,35 @@
+set(CPPCHECK_ENABLE "--enable=all" "--force")
+set(CPPCHECK_STD "--std=c11")
+
+# unmatchedSuppression: When an error doesn't occur we get an error called unmatchedSuppression
+# unusedFunction: functions that are not used. Throws false positives when interrupt functions are defined
+# missingIncludeSystem: We do not require the system includes to be passed into cppcheck
+set(CPPCHECK_SUPPRESS 
+    "--suppress=unmatchedSuppression"
+    "--suppress=unusedFunction"
+    "--suppress=missingIncludeSystem"
+
+    # Third party library suppressions
+    "--suppress=*:*l0_lowlevel/arm/cmsis/core/*"
+    "--suppress=*:*l1_third_party/FreeRTOS/*"
+)
+
+set(CPPCHECK_ADDITIONAL_OPTIONS 
+    "--error-exitcode=1"
+    "-q"
+)
+
+# Cppcheck directory for intermediate files
+file(MAKE_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/cppcheck_build")
+set(CPPCHECK_BUILDDIR "--cppcheck-build-dir=${CMAKE_CURRENT_BINARY_DIR}/cppcheck_build")
+
+# CMake generates compile_commands.json which can be used by cppcheck
+set(CPPCHECK_PROJECT "--project=${CMAKE_CURRENT_BINARY_DIR}/compile_commands.json")
+
+# Final command
+set(CMAKE_C_CPPCHECK "cppcheck"
+    ${CPPCHECK_BUILDDIR}
+    ${CPPCHECK_ENABLE}
+    ${CPPCHECK_SUPPRESS}
+    ${CPPCHECK_ADDITIONAL_OPTIONS}
+)

Template/Minimal_Tools/l0_lowlevel/newlib/syssbrk.c

@@ -28,8 +28,10 @@ caddr_t _sbrk(int increment) {
 
   char *heap_limit = (char *)&__HeapLimit;
   char *prev_heap_end = heap_end;
-  if ((heap_end + increment) > (char *)heap_limit) {
-    return ((void *)-1); // error - no more memory
+
+  // We are comparing addresses here
+  if ((size_t)(heap_end + increment) > (size_t)heap_limit) {
+    return NULL; // error - no more memory
   }
 
   heap_end += increment;

Template/Minimal_Tools/l5_application/STM32L475xx_main.c

@@ -39,7 +39,7 @@ static void blink_task(void *arg) {
 static void uart_write_task(void *arg) {
   uint32_t counter = 0;
   while (1) {
-    printf("Hello World: %ld\r\n", counter);
+    printf("Hello World: %u\r\n", counter);
     counter++;
     vTaskDelay(1000);
   }
@@ -49,8 +49,8 @@ static void uart_read_task(void *arg) {
   char buf[20] = {0};
   uint32_t counter = 0;
   while (1) {
-    scanf("%s", buf);
-    printf("Recv %ld: %s\r\n", counter, buf);
+    scanf("%19s", buf);
+    printf("Recv %u: %s\r\n", counter, buf);
     counter++;
   }
 }
@@ -66,6 +66,15 @@ static void gpio_input_task(void *arg) {
   }
 }
 
+// * Uncomment the function below to see how cppcheck works
+// int foo(int x) {
+//   int buf[10] = {0};
+//   if (x == 1000) {
+//     buf[x] = x; // <- ERROR
+//   }
+//   return buf[x];
+// }
+
 int main(void) {
   printf("Main\r\n");
 // Port specific code