Fix exported MLIR_TABLEGEN_EXE

LLVM_OPTIMIZED_TABLEGEN results in MLIR_TABLEGEN_EXE pointing to
an absolute path in the build directory.  This doesn't work
when exporting to an install directory.  This patch fixes the exported
information for an install directory to refer to the installed
mlir-tblgen.  (Note that this is probably a debug version if
LLVM_OPTIMIZED_TABLEGEN is set)

Author: stephenneuendorffer

mlir/cmake/modules/CMakeLists.txt

@@ -27,6 +27,9 @@ set(MLIR_CONFIG_INCLUDE_DIRS
   "${MLIR_SOURCE_DIR}/include"
   "${MLIR_BINARY_DIR}/include"
   )
+# Refer to the best host mlir-tbgen, which might be a host-optimized version
+set(MLIR_CONFIG_TABLEGEN_EXE "${MLIR_TABLEGEN_EXE}")
+
 configure_file(
   ${CMAKE_CURRENT_SOURCE_DIR}/MLIRConfig.cmake.in
   ${mlir_cmake_builddir}/MLIRConfig.cmake
@@ -52,6 +55,10 @@ get_config_exports_includes(MLIR MLIR_CONFIG_INCLUDE_EXPORTS)
 set(MLIR_CONFIG_INCLUDE_DIRS
   "\${MLIR_INSTALL_PREFIX}/include"
   )
+# Ensure that we are using the installed mlir-tblgen. This might not be MLIR_TABLEGEN_EXE
+# if we're building with a host-optimized mlir-tblgen (with LLVM_OPTIMIZED_TABLEGEN).
+set(MLIR_CONFIG_TABLEGEN_EXE mlir-tblgen)
+
 configure_file(
   ${CMAKE_CURRENT_SOURCE_DIR}/MLIRConfig.cmake.in
   ${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/MLIRConfig.cmake

mlir/cmake/modules/MLIRConfig.cmake.in

@@ -8,7 +8,7 @@ find_package(LLVM REQUIRED CONFIG
 set(MLIR_EXPORTED_TARGETS "@MLIR_EXPORTS@")
 set(MLIR_CMAKE_DIR "@MLIR_CONFIG_CMAKE_DIR@")
 set(MLIR_INCLUDE_DIRS "@MLIR_CONFIG_INCLUDE_DIRS@")
-set(MLIR_TABLEGEN_EXE "@MLIR_TABLEGEN_EXE@")
+set(MLIR_TABLEGEN_EXE "@MLIR_CONFIG_TABLEGEN_EXE@")
 set(MLIR_INSTALL_AGGREGATE_OBJECTS "@MLIR_INSTALL_AGGREGATE_OBJECTS@")
 set(MLIR_ENABLE_BINDINGS_PYTHON "@MLIR_ENABLE_BINDINGS_PYTHON@")