[MLIR] Fix Standalone dialect test to work in out-of-tree builds

[krzysz00]

Summary

When LLVM and MLIR are built as subprojects (via add_subdirectory),
the CMake configuration that indicates where the MLIR libraries are is
not necessarily in the same cmake/ directory as LLVM's configuration.
This patch removes that assumption about where MLIRConfig.cmake is
located.

(As an additional none, the %llvm_lib_dir substitution was never
defined, and so find_package(MLIR) in the build was succeeding for
other reasons.)

[krzysz00]

Not sure if this is the right way to request a review, but there's no indication of a specific person to request from in CODE_OWNERS.txt, so this is it

[stephenneuendorffer]

Thanks for looking at this!

mlir/test/CMakeLists.txt

22

Maybe this should be called MLIR_CMAKE_DIR, which is the same variable that is exported by MLIRConfig.cmake? the "CONFIG" in MLIR_CONFIG_CMAKE_DIR I think is intended to imply that it is being implicitly passed to config_file, but that's not happening in this case.

[krzysz00]

Rename variables per review comments.

[krzysz00]

Can someone land this? I don't have write access.

mlir/test/CMakeLists.txt

llvm_canonicalize_cmake_booleans(
   MLIR_ENABLE_CUDA_CONVERSIONS
   MLIR_ENABLE_CUDA_RUNNER
   MLIR_ENABLE_ROCM_CONVERSIONS
   MLIR_ENABLE_ROCM_RUNNER
   MLIR_ENABLE_SPIRV_CPU_RUNNER
   MLIR_ENABLE_VULKAN_RUNNER
   )
 
+# Passed to lit.site.cfg.py.so that the out of tree Standalone dialect test
+# can find MLIR's CMake configuration
+set(MLIR_CMAKE_DIR
+  "${CMAKE_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX}/cmake/mlir")
+
 # Passed to lit.site.cfg.py.in to set up the path where to find the libraries
 # for linalg integration tests.
 set(MLIR_DIALECT_LINALG_INTEGRATION_TEST_LIB_DIR ${CMAKE_LIBRARY_OUTPUT_DIRECTORY})
 set(MLIR_RUNNER_UTILS_DIR ${CMAKE_LIBRARY_OUTPUT_DIRECTORY})
 
 # Passed to lit.site.cfg.py.in to set up the path where to find the libraries
 # for the mlir spirv / vulkan runner tests.
 set(MLIR_SPIRV_WRAPPER_LIBRARY_DIR ${CMAKE_LIBRARY_OUTPUT_DIRECTORY})

mlir/test/Examples/standalone/lit.local.cfg

 config.substitutions.append(("%cmake", config.host_cmake))
 config.substitutions.append(("%host_cxx", config.host_cxx))
 config.substitutions.append(("%host_cc", config.host_cc))
 config.substitutions.append(("%enable_libcxx", config.enable_libcxx))
+config.substitutions.append(
+    ("%mlir_cmake_dir", config.mlir_cmake_dir))

mlir/test/Examples/standalone/test.toy

-# RUN: %cmake %mlir_src_root/examples/standalone -DCMAKE_CXX_COMPILER=%host_cxx -DCMAKE_C_COMPILER=%host_cc -DLLVM_ENABLE_LIBCXX=%enable_libcxx -DMLIR_DIR=%llvm_lib_dir/cmake/mlir ; %cmake --build . --target check-standalone | tee %t | FileCheck %s
+# RUN: %cmake %mlir_src_root/examples/standalone -DCMAKE_CXX_COMPILER=%host_cxx -DCMAKE_C_COMPILER=%host_cc -DLLVM_ENABLE_LIBCXX=%enable_libcxx -DMLIR_DIR=%mlir_cmake_dir ; %cmake --build . --target check-standalone | tee %t | FileCheck %s
 
 # CHECK: Passed: 3
 # UNSUPPORTED: windows, android

mlir/test/lit.site.cfg.py.in

 config.host_ldflags = '@HOST_LDFLAGS@'
 config.llvm_use_sanitizer = "@LLVM_USE_SANITIZER@"
 config.llvm_host_triple = '@LLVM_HOST_TRIPLE@'
 config.host_arch = "@HOST_ARCH@"
 config.mlir_src_root = "@MLIR_SOURCE_DIR@"
 config.mlir_obj_root = "@MLIR_BINARY_DIR@"
 config.mlir_runner_utils_dir = "@MLIR_RUNNER_UTILS_DIR@"
 config.mlir_tools_dir = "@MLIR_TOOLS_DIR@"
+config.mlir_cmake_dir = "@MLIR_CMAKE_DIR@"
 config.linalg_test_lib_dir = "@MLIR_DIALECT_LINALG_INTEGRATION_TEST_LIB_DIR@"
 config.build_examples = @LLVM_BUILD_EXAMPLES@
 config.run_cuda_tests = @MLIR_ENABLE_CUDA_CONVERSIONS@
 config.enable_cuda_runner = @MLIR_ENABLE_CUDA_RUNNER@
 config.run_rocm_tests = @MLIR_ENABLE_ROCM_CONVERSIONS@
 config.enable_rocm_runner = @MLIR_ENABLE_ROCM_RUNNER@
 config.spirv_wrapper_library_dir = "@MLIR_SPIRV_WRAPPER_LIBRARY_DIR@"
 config.enable_spirv_cpu_runner = @MLIR_ENABLE_SPIRV_CPU_RUNNER@