OpenMP in LLVM Multi-company Telecom Meeting Minutes April 22nd

Next Meeting : May 20th


  • -fopenmp-version=45. Should we make 50 the default.
  • Greg doesn’t mind switching to 50 if we have reasonable implementation of 5.0 and want it to be the default for LLVM 11.
  • Johannes said to be able to make it to for LLVM 11 release we need to make it default soon so it can be tested.
  • Informal poll by Grep indicated no one was against it. Greg will be making the change in LLVM
  • Just before release we can revisit if any issues or objection of reverting to 45.- Johannes has started a Command Center for OpenMP optimizations. Requested everybody to look at it and provide feedback

Support fat static library

  • George uploaded a patch which uses partial linking. This does not support device only static library.
  • To also support device only libraries need to extract all the device code from the library and pass it to device compilation.
  • There are 2 schemes : passing the extracted object as individual objs to device compilation (Intel implementation)

or creating a device only archive and using it in device compilation (AMD implementation)

  • The advantage with archives is that they are linked is only when needed instead of object file which are all linked in.
  • The kernel entry points are referenced from host code and the entire archive has to be linked in on the device

or have some smartness of using the host target table to bring in only the kernels that are needed.

  • AMD likes using the existing bundler tools to implement the functionality.
  • There was concern if the object file were nonstandard then archiver tool cannot be used.

Hal suggested that if we have a linker plugin then the plugin can be designed to handle any format

  • Currently the extraction tool does not create a host only archive.
  • Compiler may not use all the search path a linker uses.

Hal : Is there a way to extract that code from linker and share that code with compiler and linker.

We will continue this discussion via email and also next meeting.

Roll Call :