2 files changed, 42 insertions, 5 deletions
diff --git a/CMakeLists.txt b/CMakeLists.txt
index f634503b45..ac7da6554d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -114,12 +114,13 @@ set(LLVM_COMMON_DEPENDS ${LLVM_COMMON_DEPENDS} ${LLVM_LIBS} )
 set(LLVM_TABLEGEN "tblgen" CACHE
   STRING "Native TableGen executable.")
 
+add_subdirectory(utils/TableGen)
+
 if( CMAKE_CROSSCOMPILING )
+  # This adds a dependency on target `tblgen', so must go after utils/TableGen
   include( CrossCompileLLVM )
 endif( CMAKE_CROSSCOMPILING )
 
-add_subdirectory(utils/TableGen)
-
 add_custom_command(OUTPUT ${llvm_builded_incs_dir}/Intrinsics.gen
   COMMAND ${LLVM_TABLEGEN} -gen-intrinsic -I ${LLVM_MAIN_INCLUDE_DIR} ${LLVM_MAIN_INCLUDE_DIR}/llvm/Intrinsics.td -o ${llvm_builded_incs_dir}/Intrinsics.gen
   DEPENDS tblgen
diff --git a/cmake/modules/CrossCompileLLVM.cmake b/cmake/modules/CrossCompileLLVM.cmake
index 0377c05614..36ae306d01 100644
--- a/cmake/modules/CrossCompileLLVM.cmake
+++ b/cmake/modules/CrossCompileLLVM.cmake
@@ -1,6 +1,42 @@
-# TODO: Build a native tblgen when cross-compiling, if the user
-# didn't set LLVM_TABLEGEN. Then, remove this check:
-if( CMAKE_CROSSCOMPILING AND ${LLVM_TABLEGEN} STREQUAL "tblgen" )
+
+if( ${LLVM_TABLEGEN} STREQUAL "tblgen" )
+  # TODO: remove this when autobuilding the native tblgen works.
   message(FATAL_ERROR
     "Set LLVM_TABLEGEN to the full route to a native tblgen executable")
+
+  message(STATUS "Configuring native TableGen...")
+  set(CX_NATIVE_TG_DIR "${CMAKE_BINARY_DIR}/native")
+
+  execute_process(COMMAND ${CMAKE_COMMAND} -E make_directory ${CX_NATIVE_TG_DIR}
+    RESULT_VARIABLE CX_NATIVE_TG_RV)
+  if( NOT CX_NATIVE_TG_RV EQUAL 0 )
+    message(FATAL_ERROR "Failed to create directory ${CX_NATIVE_TG_DIR}")
+  endif()
+
+  execute_process(
+    COMMAND ${CMAKE_COMMAND} -UMAKE_TOOLCHAIN_FILE -DCMAKE_BUILD_TYPE=Release ${CMAKE_SOURCE_DIR}
+    WORKING_DIRECTORY ${CX_NATIVE_TG_DIR}
+    RESULT_VARIABLE CX_NATIVE_TG_RV
+    ERROR_VARIABLE CX_NATIVE_TG_ERROR)
+  if( NOT CX_NATIVE_TG_RV EQUAL 0 )
+    message(FATAL_ERROR
+      "Error while configuring native TableGen:\n${CX_NATIVE_TG_ERROR}")
+  endif()
+
+  message(STATUS "Native TableGen configured.")
+
+  set(LLVM_TABLEGEN "${CX_NATIVE_TG_DIR}/bin/tblgen")
+
+  add_custom_command(OUTPUT ${LLVM_TABLEGEN}
+    COMMAND ${CMAKE_BUILD_TOOL} -C ${CX_NATIVE_TG_DIR}/utils/TableGen
+    COMMENT "Building native TableGen...")
+  add_custom_target(NativeTableGen DEPENDS ${LLVM_TABLEGEN})
+  add_dependencies(tblgen NativeTableGen)
+
+  # TODO: We should clean the native build when the `clean target
+  # is invoked. This doesn't work.
+#   add_custom_command(TARGET clean
+#     COMMAND ${CMAKE_BUILD_TOOL} -C ${CX_NATIVE_TG_DIR}/utils/TableGen clean
+#     POST_BUILD
+#     COMMENT "Cleaning native TableGen...")
 endif()