Fix multiple MKL targets

Author: huydhn

CMakeLists.txt

@@ -614,6 +614,8 @@ if(BUILD_EXECUTORCH_PORTABLE_OPS)
 endif()
 
 if(EXECUTORCH_BUILD_KERNELS_OPTIMIZED)
+  # find pytorch lib here to make it available to all sub-directories
+  find_package_torch_headers()
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/kernels/optimized)
 endif()
 
@@ -750,7 +752,9 @@ if(EXECUTORCH_BUILD_PYBIND)
   endif()
 
   # find pytorch lib, to allow pybind to take at::Tensor as input/output
-  find_package(Torch CONFIG REQUIRED)
+  if(NOT TARGET torch)
+    find_package(Torch CONFIG REQUIRED)
+  endif()
   find_library(
     TORCH_PYTHON_LIBRARY torch_python PATHS "${TORCH_INSTALL_PREFIX}/lib"
   )

build/Codegen.cmake

@@ -146,7 +146,9 @@ function(gen_custom_ops_aot_lib)
     ${_out_dir}/CustomOpsNativeFunctions.h "${GEN_KERNEL_SOURCES}"
   )
   # Find `Torch`.
-  find_package(Torch REQUIRED)
+  if(NOT TARGET torch)
+    find_package(Torch REQUIRED)
+  endif()
   # This lib uses ATen lib, so we explicitly enable rtti and exceptions.
   target_compile_options(${GEN_LIB_NAME} PRIVATE -frtti -fexceptions)
   target_compile_definitions(${GEN_LIB_NAME} PRIVATE USE_ATEN_LIB=1)

build/Utils.cmake

@@ -336,7 +336,9 @@ macro(find_package_torch_headers)
     set(OLD_CMAKE_FIND_ROOT_PATH_MODE_${mode_kind} ${CMAKE_FIND_ROOT_PATH_MODE_${mode_kind}})
     set(CMAKE_FIND_ROOT_PATH_MODE_${mode_kind} BOTH)
   endforeach()
-  find_package(Torch CONFIG REQUIRED)
+  if(NOT TARGET torch)
+    find_package(Torch CONFIG REQUIRED)
+  endif()
   foreach(mode_kind IN ITEMS PACKAGE LIBRARY INCLUDE)
     set(CMAKE_FIND_ROOT_PATH_MODE_${mode_kind} ${OLD_CMAKE_FIND_ROOT_PATH_MODE_${mode_kind}})
   endforeach()

extension/llm/custom_ops/CMakeLists.txt

@@ -69,7 +69,9 @@ install(TARGETS custom_ops DESTINATION lib)
 
 if(EXECUTORCH_BUILD_KERNELS_CUSTOM_AOT)
   # Add a AOT library
-  find_package(Torch CONFIG REQUIRED)
+  if(NOT TARGET torch)
+    find_package(Torch CONFIG REQUIRED)
+  endif()
   add_library(
     custom_ops_aot_lib SHARED
     ${_custom_ops__srcs}

kernels/optimized/CMakeLists.txt

@@ -61,7 +61,6 @@ message("Generated files ${gen_command_sources}")
 
 list(TRANSFORM _optimized_kernels__srcs PREPEND "${EXECUTORCH_ROOT}/")
 add_library(optimized_kernels ${_optimized_kernels__srcs})
-find_package_torch_headers()
 target_include_directories(optimized_kernels PRIVATE ${TORCH_INCLUDE_DIRS} "${EXECUTORCH_ROOT}/third-party/pocketfft")
 target_link_libraries(
   optimized_kernels PRIVATE executorch_core cpublas extension_threadpool