[cmake] Use source-groups in Polly

[ctetreau]

Summary

• Configure CMake to setup source-groups for Polly. Source groups

describe how source files should be organized in IDEs. By default, all
headers are dumped into one folder under PollyCore and all source files
into another. On disk, these files are organized into folders, but this
isn't reflected in the IDE. This change uses CMake source groups to have
the IDE reflect the on disk layout. This will make it easier to visualize
the project structure for users of Visual Studio and XCode

Change-Id: Ifc8f0cc79850df3d88b7ed165a8554715a3a2753

[grosser]

This looks reasonable from my side.

[Meinersbur]

polly/cmake/polly_macros.cmake

102

Why not using GLOB_RECURSE such that setup_polly_source_groups_helper does not need to call itself?

[ctetreau]

polly/cmake/polly_macros.cmake

102

Suppose we have this directory structure:

root
|-------outer
|       |-------inner
|-a.cpp |-c.cpp |-e.cpp
|-b.cpp |-d.cpp |-f.cpp

file with GLOB_RECURSE would return a list similar to this:

[ root\outer\inner\e.cpp, root\outer\inner\f.cpp, root\outer\c.cpp, root\outer\d.cpp, root\a.cpp, root\b.cpp ]

However, if we were to pass this list to source_group, we'd be in the same situation that we started in. What we need to do is to have three lists:

[ root\outer\inner\e.cpp, root\outer\inner\f.cpp ]
[ root\outer\c.cpp, root\outer\d.cpp ]
[ root\a.cpp, root\b.cpp ]

We also need three calls to source_group. If ${prefix} = "src", we need:

source_group("src\\outer\\inner" FILES root\outer\inner\e.cpp, root\outer\inner\f.cpp)
source_group("src\\outer" FIELS root\outer\c.cpp, root\outer\d.cpp)
source_group("src" FILES root\a.cpp, root\b.cpp)

Splitting the lists and computing the first argument to source group are the complicating factors. We could derive this information from the result of the recursive glob, that wouldn't be any simpler than just recursing and doing the non-recursive glob.

[Meinersbur]

Please add another comment for if you need someone else to do the commit.

polly/cmake/polly_macros.cmake

102

Thank you for the detailed explanation.

[ctetreau]

Thank you for doing code review. I do not have commit access, can somebody please merge this commit for me?

Thanks!

[Meinersbur]

Thank you for the patch!

polly/cmake/polly_macros.cmake

elseif(CMAKE_COMPILER_IS_GNUCC)
     foreach(_file IN LISTS _sources)
       get_source_file_property(_lang "${_file}" LANGUAGE)
       if(_lang STREQUAL "C")
         set_source_files_properties(${_file} COMPILE_FLAGS "-std=gnu99")
       endif()
     endforeach()
   endif()
 endfunction()
+
+# Recursive helper for setup_source_group. Traverse the file system and add
+# source files matching the glob_expr to the prefix, recursing into
+# subdirectories as they are encountered
+function(setup_polly_source_groups_helper pwd prefix glob_expr)
+  file(GLOB children RELATIVE ${pwd} ${pwd}/*)
+  foreach(child ${children})
+    if (IS_DIRECTORY ${pwd}/${child})
+      setup_polly_source_groups_helper(${pwd}/${child}
+        "${prefix}\\${child}" ${glob_expr})
+    endif()
+  endforeach()
+
+  file(GLOB to_add ${pwd}/${glob_expr})
+  source_group(${prefix} FILES ${to_add})
+endfunction(setup_polly_source_groups_helper)
+
+# Set up source groups in order to nicely organize source files in IDEs
+macro(setup_polly_source_groups src_root hdr_root)
+  # FIXME: The helper can be eliminated if the CMake version is increased
+  # to 3.8 or higher. If this is done, the TREE version of source_group can
+  # be used
+  setup_polly_source_groups_helper(${src_root} "Source Files" "*.cpp")
+  setup_polly_source_groups_helper(${hdr_root} "Header Files" "*.h")
+endmacro(setup_polly_source_groups)

polly/lib/CMakeLists.txt

add_llvm_pass_plugin(Polly
   Transform/MaximalStaticExpansion.cpp
   Transform/RewriteByReferenceParameters.cpp
   Transform/ScopInliner.cpp
   ${POLLY_HEADER_FILES}
   )
 set_target_properties(obj.Polly PROPERTIES FOLDER "Polly")
 set_target_properties(Polly PROPERTIES FOLDER "Polly")
 
+if (MSVC_IDE OR XCODE)
+  # Configure source groups for Polly source files. By default, in the IDE there
+  # will be a source and include folder. In the source folder will be all the
+  # source files in a flat list, and in the include folder will be all the
+  # headers in a flat list. Sets the CMake source_group for each folder such
+  # the organization of the sources and headers in the IDE matches how it is
+  # laid out on disk
+  setup_polly_source_groups(${CMAKE_CURRENT_LIST_DIR}
+    ${CMAKE_CURRENT_LIST_DIR}/../include/polly)
+endif()
+
 # Create the library that can be linked into LLVM's tools and Polly's unittests.
 # It depends on all library it needs, such that with
 # LLVM_POLLY_LINK_INTO_TOOLS=ON, its dependencies like PollyISL are linked as
 # well.
 target_link_libraries(Polly PUBLIC
   ${ISL_TARGET}
 )