[mlir] Fix cross compiling MLIR

[isuruf]

Summary

Setting MLIR_TABLEGEN_EXE would prevent building the native tool which is used in cross-compiling

[mehdi_amini]

Thanks!

[jpienaar]

Interesting, I had not tried cross compiling it, thanks for finding/fixing!

[isuruf]

Hi, I don't have commit access. Can someone commit this?

[mehdi_amini]

I can do it: I need some info for the commit author attribution though.
(or if you rebase and use arc for your patch I should get this automatically

[isuruf]

I'm not sure what info you need. Name and email address?

Isuru Fernando <[e-mail]>

I haven't used arc, but I'll have a look to see how to use it.

mlir/CMakeLists.txt

 # MLIR project.
 set(MLIR_MAIN_SRC_DIR ${CMAKE_CURRENT_SOURCE_DIR}/include ) # --src-root
 set(MLIR_INCLUDE_DIR ${CMAKE_CURRENT_BINARY_DIR}/include ) # --includedir
-set(MLIR_TABLEGEN_EXE mlir-tblgen)
 
 set(MLIR_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
 set(MLIR_BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR})
 
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules")
 
 include(AddMLIR)
 

 add_definitions(-DMLIR_CUDA_CONVERSIONS_ENABLED=${MLIR_CUDA_CONVERSIONS_ENABLED})
 
 set(MLIR_CUDA_RUNNER_ENABLED 0 CACHE BOOL "Enable building the mlir CUDA runner")
 set(MLIR_VULKAN_RUNNER_ENABLED 0 CACHE BOOL "Enable building the mlir Vulkan runner")
 
 include_directories( "include")
 include_directories( ${MLIR_INCLUDE_DIR})
 
+# Adding tools/mlir-tblgen here as calling add_tablegen sets some variables like
+# MLIR_TABLEGEN_EXE in PARENT_SCOPE which gets lost if that folder is included
+# from another directory like tools
+add_subdirectory(tools/mlir-tblgen)
+
 add_subdirectory(include/mlir)
 add_subdirectory(lib)
 add_subdirectory(unittests)
 add_subdirectory(test)
 # Tools needs to come late to ensure that MLIR_ALL_LIBS is populated.
 # Generally things after this point may depend on MLIR_ALL_LIBS or libMLIR.so.
 add_subdirectory(tools)
 

mlir/tools/CMakeLists.txt

 add_subdirectory(mlir-cuda-runner)
 add_subdirectory(mlir-cpu-runner)
 add_subdirectory(mlir-opt)
-add_subdirectory(mlir-tblgen)
 add_subdirectory(mlir-translate)
 add_subdirectory(mlir-vulkan-runner)
 add_subdirectory(mlir-shlib)