[Openmp-commits] [PATCH] D111987: [libomptarget][nfc]Generalise DeviceRTL cmake to allow building for amdgpu

[Jon Chesterfield via Phabricator via Openmp-commits]

JonChesterfield added inline comments.


================
Comment at: openmp/libomptarget/DeviceRTL/CMakeLists.txt:145
 
-# Generate a Bitcode library for all the compute capabilities the user requested
-foreach(sm ${nvptx_sm_list})
-  # TODO: replace this with declare variant and isa selector.
-  set(cuda_flags -Xclang -target-cpu -Xclang sm_${sm} "-D__CUDA_ARCH__=${sm}0")
+macro(instantiate_DeviceRTL)
+  # parameters target_cpu, target_name, target_bc_flags
----------------
Meinersbur wrote:
> Consider
> ```
> function(instantiate_DeviceRTL target_cpu target_name)
>   set(target_bc_flags ${ARGN})
> ```
> or maybe even `cmake_parse_arguments` of more options might be added in the future.
I spent quite a while permuting function and macro trying to get names on parameters and none of it ran correctly, ending up with parameter names in a comment. 

Perhaps cmake thinks a function takes a list and peels off the named arguments, implicit &rest style?

How would one call such a function? 


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Comment at: openmp/libomptarget/DeviceRTL/CMakeLists.txt:217
   # Copy library to destination.
+  # Note: This is acting on the llvm-link'ed library, not the opt'ed one
   add_custom_command(TARGET ${bclib_target_name} POST_BUILD
----------------
Meinersbur wrote:
> [not related to this patch] There seems to be a serious mistake:
> ```
>   add_custom_command(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/${bclib_name}_opt
>       COMMAND ${OPT_TOOL} ${link_opt_flags} ${CMAKE_CURRENT_BINARY_DIR}/${bclib_name}
>                       -o ${CMAKE_CURRENT_BINARY_DIR}/${bclib_name}
> ```
> Says it would generate the `${bclib_name}_opt` file, but the `-o` parameter points to `${bclib_name}`, overwriting the input file.
Maybe? Install copies bclib_name, which was overwritten in place, so perhaps the OUTPUT statement doesn't need to match the file created.

It would certainly be clearer if we created ${bclib_name}_link.bc or similar as an intermediate file and fed that to opt to get ${bc_lib} which was then installed.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D111987/new/

https://reviews.llvm.org/D111987