[Flang] add some cmake code to allow for out-of-tree building of MLIR and LLVM

[schweitz]

Summary

The flang(f18) developers desire a way to build llvm and mlir separately for installation and then build the flang front-end out of tree. This patch adds some cmake infrastructure to allow that development environment to behave correctly.

[jpienaar]

Nice, seems to match what clang does here too so that's good to keep it in sync

mlir/CMakeLists.txt

8–9

Cant this be removed now?

39–40

Can this be removed now?

mlir/cmake/modules/CMakeLists.txt

2–4

I was going to comment "What does clang do?" and then I saw they have this exact same comment ;-)

29–30

Nit: could you indent these to show the nesting?

36

Same re indent

44–47

Leftover from testing?

52

Could you add a comment for this section?

[schweitz]

mlir/CMakeLists.txt

8–9

Possibly. We can give it a try.

mlir/cmake/modules/CMakeLists.txt

29–30

Sure. :)

44–47

This was leftover from cobbling things together from other LLVM projects. Other projects seem to setup this XXXConfig.cmake file, but I found it wasn't needed here.

We can remove these commented out lines, if you prefer. I left them with the chance someone who knew CMake better had good reasons to build out an MLIRConfig.cmake rule.

52

I can give it a shot.

[jpienaar]

I think you may have forgotten to upload the changed diff :) In general I think this looks good, I'd like to remove the duplicate functions but beyond that this should be good.

mlir/cmake/modules/CMakeLists.txt

44–47

Lets remove them, instead thanks.

[schweitz]

mlir/cmake/modules/CMakeLists.txt

29–30

Actually, this looks like it is in column-0 because it is quoted. I'm going to leave it.

[jpienaar]

Looks good thanks

[mehdi_amini]

Do you need someone to land this or do you have commit access now @schweitz ?

[schweitz]

In D72418#1828296, @mehdi_amini wrote:

Do you need someone to land this or do you have commit access now @schweitz ?

I will need someone to land it. I don't have commit access. Thanks in advance.

[mehdi_amini]

Can you rebase the patch? It does not apply right now

[mehdi_amini]

Do you have the ability to use arc by the way? It enables the CI testing to build/test revision here

[awson]

This patch breaks Windows MSVC build, former correct ${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/lib/${LIB}.lib now suddenly becomes wrong ${LIB}.

[jpienaar]

In D72418#1835438, @awson wrote:

This patch breaks Windows MSVC build, former correct ${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/lib/${LIB}.lib now suddenly becomes wrong ${LIB}.

I'll revert this part to what it was given https://bugs.llvm.org/show_bug.cgi?id=44660

mlir/CMakeLists.txt

 # MLIR project.
 set(MLIR_MAIN_SRC_DIR ${CMAKE_CURRENT_SOURCE_DIR}/include ) # --src-root
 set(MLIR_INCLUDE_DIR ${CMAKE_CURRENT_BINARY_DIR}/include ) # --includedir
 set(MLIR_TABLEGEN_EXE mlir-tblgen)
 
 set(MLIR_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
 set(MLIR_BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR})
 
-function(mlir_tablegen ofn)
-  tablegen(MLIR ${ARGV} "-I${MLIR_MAIN_SRC_DIR}" "-I${MLIR_INCLUDE_DIR}")
-  set(TABLEGEN_OUTPUT ${TABLEGEN_OUTPUT} ${CMAKE_CURRENT_BINARY_DIR}/${ofn}
-      PARENT_SCOPE)
-endfunction()
+list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules")
 
 function(add_mlir_dialect dialect dialect_doc_filename)
   set(LLVM_TARGET_DEFINITIONS ${dialect}.td)
   mlir_tablegen(${dialect}.h.inc -gen-op-decls)
   mlir_tablegen(${dialect}.cpp.inc -gen-op-defs)
   add_public_tablegen_target(MLIR${dialect}IncGen)
   add_dependencies(mlir-headers MLIR${dialect}IncGen)
 
   # Generate Dialect Documentation
   set(LLVM_TARGET_DEFINITIONS ${dialect_doc_filename}.td)
   tablegen(MLIR ${dialect_doc_filename}.md -gen-op-doc "-I${MLIR_MAIN_SRC_DIR}" "-I${MLIR_INCLUDE_DIR}")
   set(GEN_DOC_FILE ${MLIR_BINARY_DIR}/docs/Dialects/${dialect_doc_filename}.md)
   add_custom_command(
           OUTPUT ${GEN_DOC_FILE}
           COMMAND ${CMAKE_COMMAND} -E copy
                   ${CMAKE_CURRENT_BINARY_DIR}/${dialect_doc_filename}.md
                   ${GEN_DOC_FILE}
           DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/${dialect_doc_filename}.md)
   add_custom_target(${dialect_doc_filename}DocGen DEPENDS ${GEN_DOC_FILE})
   add_dependencies(mlir-doc ${dialect_doc_filename}DocGen)
 endfunction()
 
+include(AddMLIR)
+
 # Installing the headers and docs needs to depend on generating any public
 # tablegen'd targets.
 add_custom_target(mlir-headers)
 set_target_properties(mlir-headers PROPERTIES FOLDER "Misc")
 add_custom_target(mlir-doc)
 
-# TODO: This is to handle the current static registration, but should be
-# factored out a bit.
-function(whole_archive_link target)
-  if("${CMAKE_SYSTEM_NAME}" STREQUAL "Darwin")
-    set(link_flags "-L${CMAKE_BINARY_DIR}/lib ")
-    FOREACH(LIB ${ARGN})
-      string(CONCAT link_flags ${link_flags} "-Wl,-force_load ${CMAKE_BINARY_DIR}/lib/lib${LIB}.a ")
-    ENDFOREACH(LIB)
-  elseif(MSVC)
-    FOREACH(LIB ${ARGN})
-      string(CONCAT link_flags ${link_flags} "/WHOLEARCHIVE:${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/lib/${LIB}.lib ")
-    ENDFOREACH(LIB)
-  else()
-    set(link_flags "-L${CMAKE_BINARY_DIR}/lib -Wl,--whole-archive,")
-    FOREACH(LIB ${ARGN})
-      string(CONCAT link_flags ${link_flags} "-l${LIB},")
-    ENDFOREACH(LIB)
-    string(CONCAT link_flags ${link_flags} "--no-whole-archive")
-  endif()
-  set_target_properties(${target} PROPERTIES LINK_FLAGS ${link_flags})
-endfunction(whole_archive_link)
-
 # Build the CUDA conversions and run according tests if the NVPTX backend
 # is available
 if ("NVPTX" IN_LIST LLVM_TARGETS_TO_BUILD)
   set(MLIR_CUDA_CONVERSIONS_ENABLED 1)
 else()
   set(MLIR_CUDA_CONVERSIONS_ENABLED 0)
 endif()
 
 set(MLIR_CUDA_RUNNER_ENABLED 0 CACHE BOOL "Enable building the mlir CUDA runner")
install(DIRECTORY include/mlir include/mlir-c
     PATTERN "*.td"
     PATTERN "LICENSE.TXT"
     )
 
   install(DIRECTORY ${MLIR_INCLUDE_DIR}/mlir ${MLIR_INCLUDE_DIR}/mlir-c
     DESTINATION include
     COMPONENT mlir-headers
     FILES_MATCHING
+    PATTERN "*.def"
     PATTERN "*.h"
     PATTERN "*.gen"
     PATTERN "*.inc"
+    PATTERN "*.td"
     PATTERN "CMakeFiles" EXCLUDE
     PATTERN "config.h" EXCLUDE
     )
 
   if (NOT LLVM_ENABLE_IDE)
     add_llvm_install_targets(install-mlir-headers
                              DEPENDS mlir-headers
                              COMPONENT mlir-headers)
   endif()
 endif()
+
+add_subdirectory(cmake/modules)

mlir/cmake/modules/AddMLIR.cmake

+function(mlir_tablegen ofn)
+  tablegen(MLIR ${ARGV} "-I${MLIR_MAIN_SRC_DIR}" "-I${MLIR_INCLUDE_DIR}")
+  set(TABLEGEN_OUTPUT ${TABLEGEN_OUTPUT} ${CMAKE_CURRENT_BINARY_DIR}/${ofn}
+      PARENT_SCOPE)
+endfunction()
+
+# TODO: This is to handle the current static registration, but should be
+# factored out a bit.
+function(whole_archive_link target)
+  if("${CMAKE_SYSTEM_NAME}" STREQUAL "Darwin")
+    set(link_flags "-L${CMAKE_BINARY_DIR}/lib ")
+    FOREACH(LIB ${ARGN})
+      string(CONCAT link_flags ${link_flags} "-Wl,-force_load ${CMAKE_BINARY_DIR}/lib/lib${LIB}.a ")
+    ENDFOREACH(LIB)
+  elseif(MSVC)
+    FOREACH(LIB ${ARGN})
+      string(CONCAT link_flags ${link_flags} "/WHOLEARCHIVE:${LIB} ")
+    ENDFOREACH(LIB)
+  else()
+    set(link_flags "-L${CMAKE_BINARY_DIR}/lib -Wl,--whole-archive,")
+    FOREACH(LIB ${ARGN})
+      string(CONCAT link_flags ${link_flags} "-l${LIB},")
+    ENDFOREACH(LIB)
+    string(CONCAT link_flags ${link_flags} "--no-whole-archive")
+  endif()
+  set_target_properties(${target} PROPERTIES LINK_FLAGS ${link_flags})
+endfunction(whole_archive_link)

mlir/cmake/modules/CMakeLists.txt

+# Generate a list of CMake library targets so that other CMake projects can
+# link against them. LLVM calls its version of this file LLVMExports.cmake, but
+# the usual CMake convention seems to be ${Project}Targets.cmake.
+set(MLIR_INSTALL_PACKAGE_DIR lib${LLVM_LIBDIR_SUFFIX}/cmake/llvm)
+set(mlir_cmake_builddir "${CMAKE_BINARY_DIR}/${MLIR_INSTALL_PACKAGE_DIR}")
+
+# Keep this in sync with llvm/cmake/CMakeLists.txt!
+set(LLVM_INSTALL_PACKAGE_DIR lib${LLVM_LIBDIR_SUFFIX}/cmake/llvm)
+set(llvm_cmake_builddir "${LLVM_BINARY_DIR}/${LLVM_INSTALL_PACKAGE_DIR}")
+
+get_property(MLIR_EXPORTS GLOBAL PROPERTY MLIR_EXPORTS)
+export(TARGETS ${MLIR_EXPORTS} FILE ${mlir_cmake_builddir}/MlirTargets.cmake)
+
+# Generate MlirConfig.cmake for the build tree.
+set(MLIR_CONFIG_CMAKE_DIR "${mlir_cmake_builddir}")
+set(MLIR_CONFIG_LLVM_CMAKE_DIR "${llvm_cmake_builddir}")
+set(MLIR_CONFIG_EXPORTS_FILE "${mlir_cmake_builddir}/MlirTargets.cmake")
+set(MLIR_CONFIG_INCLUDE_DIRS
+  "${MLIR_SOURCE_DIR}/include"
+  "${MLIR_BINARY_DIR}/include"
+  )
+set(MLIR_CONFIG_CMAKE_DIR)
+set(MLIR_CONFIG_LLVM_CMAKE_DIR)
+set(MLIR_CONFIG_EXPORTS_FILE)
+
+# Generate MlirConfig.cmake for the install tree.
+set(MLIR_CONFIG_CODE "
+# Compute the installation prefix from this LLVMConfig.cmake file location.
+get_filename_component(MLIR_INSTALL_PREFIX \"\${CMAKE_CURRENT_LIST_FILE}\" PATH)")
+# Construct the proper number of get_filename_component(... PATH)
+# calls to compute the installation prefix.
+string(REGEX REPLACE "/" ";" _count "${MLIR_INSTALL_PACKAGE_DIR}")
+foreach(p ${_count})
+  set(MLIR_CONFIG_CODE "${MLIR_CONFIG_CODE}
+get_filename_component(MLIR_INSTALL_PREFIX \"\${MLIR_INSTALL_PREFIX}\" PATH)")
+endforeach(p)
+set(MLIR_CONFIG_CMAKE_DIR "\${MLIR_INSTALL_PREFIX}/${MLIR_INSTALL_PACKAGE_DIR}")
+set(MLIR_CONFIG_LLVM_CMAKE_DIR "\${MLIR_INSTALL_PREFIX}/${LLVM_INSTALL_PACKAGE_DIR}")
+set(MLIR_CONFIG_EXPORTS_FILE "\${MLIR_CMAKE_DIR}/MlirTargets.cmake")
+set(MLIR_CONFIG_INCLUDE_DIRS
+  "\${MLIR_INSTALL_PREFIX}/include"
+  )
+set(MLIR_CONFIG_CODE)
+set(MLIR_CONFIG_CMAKE_DIR)
+set(MLIR_CONFIG_EXPORTS_FILE)
+
+if (NOT LLVM_INSTALL_TOOLCHAIN_ONLY)
+  # Not TOOLCHAIN ONLY, so install the MLIR parts as well
+  # Include the cmake files so other tools can use mlir-tblgen, etc.
+  get_property(mlir_has_exports GLOBAL PROPERTY MLIR_HAS_EXPORTS)
+  if(mlir_has_exports)
+    install(EXPORT MlirTargets DESTINATION ${MLIR_INSTALL_PACKAGE_DIR}
+            COMPONENT mlir-cmake-exports)
+  endif()
+
+  install(FILES #${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/MlirConfig.cmake
+    ${CMAKE_CURRENT_SOURCE_DIR}/AddMLIR.cmake
+    DESTINATION ${MLIR_INSTALL_PACKAGE_DIR}
+    COMPONENT mlir-cmake-exports)
+
+  if(NOT LLVM_ENABLE_IDE)
+    # Add a dummy target so this can be used with LLVM_DISTRIBUTION_COMPONENTS
+    add_custom_target(mlir-cmake-exports)
+    add_llvm_install_targets(install-mlir-cmake-exports
+                             COMPONENT mlir-cmake-exports)
+  endif()
+endif()