add cmake config option to enable clang-tidy with preferred options

cmake/CMakeLists.txt

@@ -104,6 +104,12 @@ endif()
 option(BUILD_TOOLS "Build and install LAMMPS tools (msi2lmp, binary2txt, chain)" OFF)
 option(BUILD_LAMMPS_SHELL "Build and install the LAMMPS shell" OFF)
 
+# allow enabling clang-tidy for C++ files
+set(ENABLE_CLANG_TIDY OFF CACHE BOOL "Include clang-tidy processing when compiling")
+if(ENABLE_CLANG_TIDY)
+  set(CMAKE_CXX_CLANG_TIDY "clang-tidy;-checks=*-header-filter=.*" CACHE LIST "")
+endif()
+
 include(GNUInstallDirs)
 file(GLOB ALL_SOURCES ${LAMMPS_SOURCE_DIR}/[^.]*.cpp)
 file(GLOB MAIN_SOURCES ${LAMMPS_SOURCE_DIR}/main.cpp)

doc/src/Build_development.rst

@@ -28,6 +28,28 @@ variable VERBOSE set to 1:
 
 ----------
 
+.. _clang-tidy
+
+Enable static code analysis with clang-tidy
+-------------------------------------------
+
+The `clang-tidy tool <https://clang.llvm.org/extra/clang-tidy/>`_ is a
+static code analysis tool to diagnose (and potentially fix) typical
+programming errors or coding style violations.  It has a modular framework
+of tests that can be adjusted to help identifying problems before they
+become bugs and also assist in modernizing large code bases (like LAMMPS).
+It can be enabled for all C++ code with the following CMake flag
+
+.. code-block:: bash
+
+   -D ENABLE_CLANG_TIDY=value    # value = no (default) or yes
+
+With this flag enabled all source files will be processed twice, first to
+be compiled and then to be analyzed. Please note that the analysis can be
+significantly more time consuming than the compilation itself.
+
+----------
+
 .. _iwyu_processing:
 
 Report missing and unneeded '#include' statements

src/arg_info.cpp

@@ -1,4 +1,3 @@
-// clang-format off
 /* ----------------------------------------------------------------------
    LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
    https://lammps.sandia.gov/, Sandia National Laboratories
@@ -14,8 +13,8 @@
 
 #include "arg_info.h"
 
-#include <stdexcept>
 #include <cstring>
+#include <stdexcept>
 
 using namespace LAMMPS_NS;
 
@@ -29,46 +28,51 @@ using namespace LAMMPS_NS;
  * \param arg      string with possible reference
  * \param allowed  integer with bitmap of allowed types of references */
 
-ArgInfo::ArgInfo(const std::string &arg, int allowed)
-  : type(NONE), dim(0), index1(-1), index2(-1)
+ArgInfo::ArgInfo(const std::string &arg, int allowed) : type(NONE), dim(0), index1(-1), index2(-1)
 {
   if ((arg.size() > 2) && (arg[1] == '_')) {
-    if ((arg[0] == 'c') && (allowed & COMPUTE))  type = COMPUTE;
-    else if ((arg[0] == 'f') && (allowed & FIX)) type = FIX;
-    else if ((arg[0] == 'v') && (allowed & VARIABLE)) type = VARIABLE;
-    else if ((arg[0] == 'd') && (allowed & DNAME)) type = DNAME;
-    else if ((arg[0] == 'i') && (allowed & INAME)) type = INAME;
+    if ((arg[0] == 'c') && (allowed & COMPUTE))
+      type = COMPUTE;
+    else if ((arg[0] == 'f') && (allowed & FIX))
+      type = FIX;
+    else if ((arg[0] == 'v') && (allowed & VARIABLE))
+      type = VARIABLE;
+    else if ((arg[0] == 'd') && (allowed & DNAME))
+      type = DNAME;
+    else if ((arg[0] == 'i') && (allowed & INAME))
+      type = INAME;
     else {
       index1 = 0;
       name = arg;
       return;
     }
 
-    std::size_t has_idx1 = arg.find('[',2);
+    std::size_t has_idx1 = arg.find('[', 2);
     if (has_idx1 != std::string::npos) {
-      name = arg.substr(2,has_idx1-2);
+      name = arg.substr(2, has_idx1 - 2);
       dim = 1;
 
-      std::size_t has_idx2 = arg.find('[',has_idx1+1);
+      std::size_t has_idx2 = arg.find('[', has_idx1 + 1);
       if (has_idx2 != std::string::npos) {
         dim = 2;
 
-        if (arg[arg.size()-1] != ']') {
+        if (arg[arg.size() - 1] != ']') {
           type = UNKNOWN;
         } else {
           try {
-            index2 = std::stoi(arg.substr(has_idx2+1,arg.size()-(has_idx2+2)));
+            index2 = std::stoi(arg.substr(has_idx2 + 1, arg.size() - (has_idx2 + 2)));
           } catch (std::invalid_argument &) {
             type = UNKNOWN;
           }
         }
-      } else has_idx2 = arg.size();
+      } else
+        has_idx2 = arg.size();
 
-      if (arg[has_idx2-1] != ']') {
+      if (arg[has_idx2 - 1] != ']') {
         type = UNKNOWN;
       } else {
         try {
-          index1 = std::stoi(arg.substr(has_idx1+1,arg.size()-(has_idx2+2)));
+          index1 = std::stoi(arg.substr(has_idx1 + 1, arg.size() - (has_idx2 + 2)));
         } catch (std::invalid_argument &) {
           type = UNKNOWN;
         }
@@ -97,8 +101,7 @@ ArgInfo::ArgInfo(const std::string &arg, int allowed)
 
 char *ArgInfo::copy_name()
 {
-  char *dest = new char[name.size()+1];
-  strcpy(dest,name.c_str());
+  char *dest = new char[name.size() + 1];
+  strcpy(dest, name.c_str());    // NOLINT
   return dest;
 }
-

src/utils.cpp

@@ -638,7 +638,7 @@ int utils::expand_args(const char *file, int line, int narg, char **arg, int mod
 char *utils::strdup(const std::string &text)
 {
   char *tmp = new char[text.size() + 1];
-  strcpy(tmp, text.c_str());
+  strcpy(tmp, text.c_str());    // NOLINT
   return tmp;
 }