Improve documentation in CMakeLists.txt

Signed-off-by: David Shah <davey1576@gmail.com>

1 files changed, 12 insertions, 3 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 494353fd..a2857d71 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,11 +1,12 @@
 # TODO: sensible minimum CMake version
 cmake_minimum_required(VERSION 3.3)
 project(nextpnr)
-
+# List of families to build
 set(FAMILIES dummy ice40)
 set(CMAKE_CXX_STANDARD 11)
 # set(CMAKE_CXX_FLAGS "-Wall -pedantic -Wextra -Werror")
 set(CMAKE_DEFIN)
+# List of Boost libraries to include
 set(boost_libs filesystem thread)
 # TODO: sensible minimum Python version
 find_package(PythonInterp 3.5 REQUIRED)
@@ -14,7 +15,9 @@ find_package(PythonLibs 3.5 REQUIRED)
 find_package(Boost REQUIRED COMPONENTS ${boost_libs})
 
 # Find Boost::Python of a suitable version in a cross-platform way
-
+# Some distributions (Arch) call it libboost_python3, others such as Ubuntu
+# call it libboost_python35. In the latter case we must consider all minor versions
+# Original source: https://github.com/BVLC/caffe/blob/master/cmake/Dependencies.cmake#L148
 set(version ${PYTHONLIBS_VERSION_STRING})
 
 STRING(REGEX REPLACE "[^0-9]" "" boost_py_version ${version})
@@ -46,12 +49,18 @@ aux_source_directory(common/ COMMON_FILES)
 foreach (family ${FAMILIES})
     string(TOUPPER ${family} ufamily)
     aux_source_directory(${family}/ ${ufamily}_FILES)
+    # Add the CLI binary target
     add_executable(nextpnr-${family} ${COMMON_FILES} ${${ufamily}_FILES})
-    # TODO: also build an importable Python module
+    # Add the importable Python module target
     PYTHON_ADD_MODULE(nextpnrpy_${family} ${COMMON_FILES} ${${ufamily}_FILES})
+    # Add any new per-architecture targets here
+
+    # Set ${family_targets} to the list of targets being build for this family
     set(family_targets nextpnr-${family} nextpnrpy_${family})
+    # Include the family-specific CMakeFile
     include(${family}/family.cmake)
     foreach (target ${family_targets})
+        # Include family-specific source files to all family targets and set defines appropriately
         target_include_directories(${target} PRIVATE ${family}/)
         target_compile_definitions(${target} PRIVATE ARCH_${ufamily} ARCHNAME=${family})
         target_link_libraries(${target} LINK_PUBLIC ${Boost_LIBRARIES} ${PYTHON_LIBRARIES})