Optionally fetch gflags for BUCK

Author: larryliu0820

.ci/scripts/unittest-linux.sh

@@ -30,6 +30,7 @@ elif [[ "$BUILD_TOOL" == "buck2" ]]; then
     # Removing this breaks sccache in the Buck build, apparently
     # because TMPDIR gets messed up? Please feel free to fix this and
     # speed up this CI job!
+    CMAKE_ARGS="-DEXECUTORCH_FETCH_GFLAGS_FOR_BUCK=ON" \
     PYTHON_EXECUTABLE=python \
     .ci/scripts/setup-linux.sh "$@"
 

CMakeLists.txt

@@ -697,6 +697,7 @@ endif()
 
 if(EXECUTORCH_BUILD_EXECUTOR_RUNNER)
   # Baseline libraries that executor_runner will link against.
+  FetchContent_gflags()
   set(_executor_runner_libs executorch gflags)
 
   if(EXECUTORCH_BUILD_KERNELS_OPTIMIZED)

third-party/CMakeLists.txt

@@ -14,12 +14,14 @@ if(BUILD_TESTING)
   add_subdirectory(googletest)
 endif()
 
-FetchContent_gflags()
-# Create a symlink from the gflags source directory to third-party/gflags
-message(STATUS "Creating a symlink from ${gflags_SOURCE_DIR} to third-party/gflags")
-execute_process(
-  COMMAND ${CMAKE_COMMAND} -E create_symlink "${gflags_SOURCE_DIR}" "${CMAKE_CURRENT_SOURCE_DIR}/gflags"
-)
+if(EXECUTORCH_FETCH_GFLAGS_FOR_BUCK)
+  FetchContent_gflags()
+  # Create a symlink from the gflags source directory to third-party/gflags
+  message(STATUS "Creating a symlink from ${gflags_SOURCE_DIR} to third-party/gflags")
+  execute_process(
+    COMMAND ${CMAKE_COMMAND} -E create_symlink "${gflags_SOURCE_DIR}" "${CMAKE_CURRENT_SOURCE_DIR}/gflags"
+  )
+endif()
 
 # MARK: - flatbuffers
 

third-party/gflags.bzl

@@ -2,10 +2,13 @@
 load(":gflags_defs.bzl", "gflags_library", "gflags_sources")
 
 def define_gflags():
-    (exported_headers, headers, srcs) = gflags_sources(namespace = [
-        "gflags",
-        "google",
-    ])
+    if native.read_config("et_oss", "enable_gflags", "true") == "true":
+        (exported_headers, headers, srcs) = gflags_sources(namespace = [
+            "gflags",
+            "google",
+        ])
+    else:
+        (exported_headers, headers, srcs) = ([], [], [])
 
     gflags_library(
         name = "gflags",

tools/cmake/FetchContent.cmake

@@ -12,7 +12,7 @@ include(FetchContent)
 # buck. Unfortunately, FetchContent bakes in generator information in the
 # fetched content. Thus, if the generator is changed, it causes build failures.
 # So, if the generator has changed, then nuke the content.
-function(_refresh_cache_if_necessary DIR)
+function(_invalidate_cache_if_generator_mismatch DIR)
   set(_generator_stamp_file "${DIR}/.executorch_cmake_generator_stamp")
   set(_current_generator "${CMAKE_GENERATOR}")
 
@@ -24,13 +24,17 @@ function(_refresh_cache_if_necessary DIR)
     endif()
   endif()
 
-  file(WRITE "${_generator_stamp_file}" "${_current_generator}")
 endfunction()
 
+# Fetch gflags, and make a symlink to third-party/gflags in the source tree.
+# Doing this to satisfy BUCK query for gflags. Also try to invalidate the cmake
+# cache if the generator has changed. Notice that symlink won't be created again
+# if it's already there.
 function(FetchContent_gflags)
-  if(NOT ${gflags_SOURCE_DIR} STREQUAL "")
-    _refresh_cache_if_necessary(${gflags_SOURCE_DIR})
-  endif()
+  # set(_symlink_target ${CMAKE_CURRENT_LIST_DIR}/../../third-party/gflags)
+  # if(IS_DIRECTORY ${_symlink_target})
+  #   _invalidate_cache_if_generator_mismatch(${_symlink_target})
+  # endif()
 
   FetchContent_Declare(
     gflags
@@ -39,4 +43,12 @@ function(FetchContent_gflags)
   )
   set(GFLAGS_INTTYPES_FORMAT C99)
   FetchContent_MakeAvailable(gflags)
+
+  # if(NOT IS_DIRECTORY ${_symlink_target})
+  #   message(STATUS "Creating a symlink from ${gflags_SOURCE_DIR} to third-party/gflags")
+  #   execute_process(
+  #     COMMAND ${CMAKE_COMMAND} -E create_symlink "${gflags_SOURCE_DIR}" "${_symlink_target}"
+  #   )
+  #   file(WRITE "${_symlink_target}/.executorch_cmake_generator_stamp" "${CMAKE_GENERATOR}")
+  # endif()
 endfunction()

tools/cmake/extract_sources.py

@@ -129,7 +129,7 @@ def get_sources(
         # If we hit here, setup.py:check_submodule() should have already run
         # but it could be that the submodules are not synced or there's local changes.
         try:
-            sources: set[str] = set(runner.run(["cquery", query] + buck_args))
+            sources: set[str] = set(runner.run(["cquery", "--config", "et_oss.enable_gflags=false", query] + buck_args))
         except RuntimeError as e:
             logger.error(
                 f"\033[31;1mFailed to query buck for sources. Failed command:\n\n"

tools/cmake/preset/default.cmake

@@ -209,6 +209,11 @@ define_overridable_option(
   "Build the Cortex-M backend"
   BOOL OFF
 )
+define_overridable_option(
+  EXECUTORCH_FETCH_GFLAGS_FOR_BUCK
+  "Fetch gflags for BUCK build/test"
+  BOOL OFF
+)
 define_overridable_option(
   EXECUTORCH_COREML_BUILD_EXECUTOR_RUNNER
   "Build CoreML executor runner."

tools/cmake/preset/llm.cmake

@@ -16,6 +16,7 @@ set_overridable_option(EXECUTORCH_BUILD_KERNELS_CUSTOM ON)
 set_overridable_option(EXECUTORCH_BUILD_KERNELS_OPTIMIZED ON)
 set_overridable_option(EXECUTORCH_BUILD_KERNELS_QUANTIZED ON)
 set_overridable_option(EXECUTORCH_BUILD_XNNPACK ON)
+set_overridable_option(EXECUTORCH_FETCH_GFLAGS_FOR_BUCK ON)
 
 if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
   set_overridable_option(EXECUTORCH_BUILD_COREML ON)