Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

[CMake] Add support for using Eigen alignment with AppleClang #1219

Merged
merged 1 commit into from
Sep 16, 2022
Merged

[CMake] Add support for using Eigen alignment with AppleClang #1219

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 2 additions & 0 deletions CMakeLists.txt
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -241,6 +241,8 @@ if(AV_EIGEN_MEMORY_ALIGNMENT)
set(EIGEN_CMAKE_ALIGNMENT_FLAGS "-DCMAKE_CXX_FLAGS:STRING=-faligned-new")
elseif(CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 6.0)
set(EIGEN_CMAKE_ALIGNMENT_FLAGS "-DCMAKE_CXX_FLAGS:STRING=-faligned-new")
elseif(CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang" AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 10.0)
set(EIGEN_CMAKE_ALIGNMENT_FLAGS "-DCMAKE_CXX_FLAGS:STRING=-faligned-new")
elseif(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC" AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 19.12)
set(EIGEN_CMAKE_ALIGNMENT_FLAGS "-DCMAKE_CXX_FLAGS:STRING=/Zc:alignedNew")
else()
Expand Down
2 changes: 2 additions & 0 deletions src/CMakeLists.txt
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -211,6 +211,8 @@ if(AV_EIGEN_MEMORY_ALIGNMENT)
AddCompilerFlag("-faligned-new")
elseif(CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 6.0)
AddCompilerFlag("-faligned-new")
elseif(CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang" AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 10.0)
AddCompilerFlag("-faligned-new")
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I'm wondering if these flags for eigen memory alignment shouldn't be a property of each target instead rather than added like this.
I'm not sure that if the library is then used as a 3rd party the flag added with AddCompilerFlag will be propagated.
Usually, if we add a flag this way (take -Wall as an example) it only applies for the current build, but if the library, once built, is used to link with another project the flag is not added automatically. It's up to the host project. In the case of warning is not an issue, but for flags that change the behavior of the code, it could.

And sadly we have a lot of template code in AV which could be compiled again by the other project. So potentially the other project is compiling this code with a different set of flags and at the same time using also compiled code of the library with another set of flags. That could turn ugly.
Any thoughts?

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I agree in principle, but I think in this particular case the work needed would outweigh the benefit due to the following reasons:

  • this flag is enabled by the user of aliceVision via AV_EIGEN_MEMORY_ALIGNMENT. Presumably the user knows what it does and will adjust their own project flags accordingly.
  • this flag is only a temporary solution until we can default to C++17.

elseif(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC" AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 19.12)
AddCompilerFlag("/Zc:alignedNew")
else()
Expand Down