[Mlir-commits] [mlir] [mlir][Python] create MLIRPythonSupport (PR #171775)

[Maksim Levental]

================
@@ -297,6 +302,51 @@ function(_mlir_python_install_sources name source_root_dir destination)
   )
 endfunction()
 
+function(build_nanobind_lib)
+  cmake_parse_arguments(ARG
+    ""
+    "INSTALL_COMPONENT;INSTALL_DESTINATION;OUTPUT_DIRECTORY"
+    ""
+    ${ARGN})
+
+  if (NB_ABI MATCHES "[0-9]t")
+    set(_ft "-ft")
+  endif()
+  # nanobind does a string match on the suffix to figure out whether to build
+  # the lib with free threading...
+  set(NB_LIBRARY_TARGET_NAME "nanobind${_ft}-${MLIR_BINDINGS_PYTHON_NB_DOMAIN}")
+  set(NB_LIBRARY_TARGET_NAME "${NB_LIBRARY_TARGET_NAME}" PARENT_SCOPE)
+  nanobind_build_library(${NB_LIBRARY_TARGET_NAME} AS_SYSINCLUDE)
+  target_compile_definitions(${NB_LIBRARY_TARGET_NAME}
+    PRIVATE
+    NB_DOMAIN=${MLIR_BINDINGS_PYTHON_NB_DOMAIN}
+  )
+  # nanobind configures with LTO for shared build which doesn't work everywhere
+  # (see https://github.com/llvm/llvm-project/issues/139602).
+  if(NOT LLVM_ENABLE_LTO)
+    set_target_properties(${NB_LIBRARY_TARGET_NAME} PROPERTIES
+      INTERPROCEDURAL_OPTIMIZATION_RELEASE OFF
+      INTERPROCEDURAL_OPTIMIZATION_MINSIZEREL OFF
+    )
+  endif()
+  if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
+    target_link_options(${NB_LIBRARY_TARGET_NAME} PRIVATE "-Wl,-z,undefs")
+  endif()
----------------
makslevental wrote:

for Darwin/Apple/MacOS nanobind already does the right thing https://github.com/wjakob/nanobind/blob/4ba51fcf795971c5d603d875ae4184bc0c9bd8e6/cmake/nanobind-config.cmake#L204 by explicitly `-U` all the necessary symbols (i.e., same reason the `undefs` is only necessary for Linux below). added a comment here.

https://github.com/llvm/llvm-project/pull/171775