Visitors now takes C++ references of ast nodes in parameter, not poin…

…ters (#297)

* Visitors now takes C++ references of ast nodes in parameter, not pointers
* Add instructions to run Python tests

CONTRIBUTING.md

@@ -126,10 +126,21 @@ do not comply with coding conventions of this project. These 2 CMake variables r
 * [pre-commit](https://pre-commit.com/)
 
 clang-format can be installed on Linux thanks
-to [LLVM apt page](http://apt.llvm.org/). On MacOS, there is a
-[brew recipe](https://gist.github.com/ffeu/0460bb1349fa7e4ab4c459a6192cbb25)
-to install clang-format 7. _cmake-format_ and _pre-commit_ utilities can be installed with *pip*.
+to [LLVM apt page](http://apt.llvm.org/). On MacOS, you can simply install llvm with brew:
+`brew install llvm`.
+_cmake-format_ and _pre-commit_ utilities can be installed with *pip*.
 
+### Validate the Python package
+
+You may run the Python test-suites if your contribution has an impact
+on the Python API:
+
+1. setup a sandbox environment with either _virtualenv_,
+  _pyenv_, or _pipenv_. For instance with _virtualenv_:
+  `python -m venv .venv && source .venv/bin/activate`
+1. build the Python package with the command: `python setup.py build`
+1. install _pytest_ Python package: `pip install pytest`
+1. execute the unit-tests: `pytest`
 
 ### Memory Leaks and clang-tidy
 

src/codegen/codegen_acc_visitor.cpp

@@ -66,12 +66,12 @@ void CodegenAccVisitor::print_backend_includes() {
 }
 
 
-std::string CodegenAccVisitor::backend_name() {
+std::string CodegenAccVisitor::backend_name() const {
     return "C-OpenAcc (api-compatibility)";
 }
 
 
-void CodegenAccVisitor::print_memory_allocation_routine() {
+void CodegenAccVisitor::print_memory_allocation_routine() const {
     printer->add_newline(2);
     auto args = "size_t num, size_t size, size_t alignment = 16";
     printer->add_line("static inline void* mem_alloc({}) {}"_format(args, "{"));
@@ -174,7 +174,8 @@ void CodegenAccVisitor::print_global_variable_device_update_annotation() {
     }
 }
 
-std::string CodegenAccVisitor::get_variable_device_pointer(std::string variable, std::string type) {
+std::string CodegenAccVisitor::get_variable_device_pointer(const std::string& variable,
+                                                           const std::string& type) const {
     if (info.artificial_cell) {
         return variable;
     }

src/codegen/codegen_acc_visitor.hpp

@@ -30,7 +30,7 @@ namespace codegen {
 class CodegenAccVisitor: public CodegenCVisitor {
   protected:
     /// name of the code generation backend
-    std::string backend_name() override;
+    std::string backend_name() const override;
 
 
     /// common includes : standard c/c++, coreneuron and backend specific
@@ -46,7 +46,7 @@ class CodegenAccVisitor: public CodegenCVisitor {
 
 
     /// memory allocation routine
-    void print_memory_allocation_routine() override;
+    void print_memory_allocation_routine() const override;
 
 
     /// annotations like "acc enter data present(...)" for main kernel
@@ -81,20 +81,21 @@ class CodegenAccVisitor: public CodegenCVisitor {
     /// update global variable from host to the device
     void print_global_variable_device_update_annotation() override;
 
-    std::string get_variable_device_pointer(std::string variable, std::string type) override;
+    std::string get_variable_device_pointer(const std::string& variable,
+                                            const std::string& type) const override;
 
 
   public:
-    CodegenAccVisitor(std::string mod_file,
-                      std::string output_dir,
+    CodegenAccVisitor(const std::string& mod_file,
+                      const std::string& output_dir,
                       LayoutType layout,
-                      std::string float_type)
+                      const std::string& float_type)
         : CodegenCVisitor(mod_file, output_dir, layout, float_type) {}
 
-    CodegenAccVisitor(std::string mod_file,
-                      std::stringstream& stream,
+    CodegenAccVisitor(const std::string& mod_file,
+                      std::ostream& stream,
                       LayoutType layout,
-                      std::string float_type)
+                      const std::string& float_type)
         : CodegenCVisitor(mod_file, stream, layout, float_type) {}
 };