[CMakeLists] Factored out cmake function that does single gyb processing

So that we can generate arbitrary output file.

Author: rintaro

cmake/modules/SwiftHandleGybSources.cmake

@@ -1,6 +1,74 @@
 include(SwiftAddCustomCommandTarget)
 include(SwiftSetIfArchBitness)
 
+# Create a target to process single gyb source with the 'gyb' tool.
+#
+# handle_gyb_source_single(
+#     dependency_out_var_name
+#     SOURCE src_gyb
+#     OUTPUT output
+#     [FLAGS [flags ...]])
+#     [DEPENDS [depends ...]]
+#     [COMMENT comment])
+#
+# dependency_out_var_name
+#   The name of a variable, to be set in the parent scope to be the target
+#   target that invoke gyb.
+#
+# src_gyb
+#   .gyb suffixed source file
+#
+# output
+#   Output filename to be generated
+#
+# flags ...
+#    gyb flags in addition to ${SWIFT_GYB_FLAGS}.
+#
+# depends ...
+#    gyb flags in addition to 'src_gyb' and sources of gyb itself.
+#
+# comment
+#    Additional comment.
+function(handle_gyb_source_single dependency_out_var_name)
+  set(options)
+  set(single_value_args SOURCE OUTPUT COMMENT)
+  set(multi_value_args FLAGS DEPENDS)
+  cmake_parse_arguments(
+      GYB_SINGLE # prefix
+      "${options}" "${single_value_args}" "${multi_value_args}" ${ARGN})
+
+  set(gyb_flags
+      "--test" # Run gyb's self-tests whenever we use it.  They're cheap
+               # enough and it keeps us honest.
+      ${SWIFT_GYB_FLAGS}
+      ${GYB_SINGLE_FLAGS})
+
+  set(gyb_tool "${SWIFT_SOURCE_DIR}/utils/gyb")
+  set(gyb_tool_source "${gyb_tool}" "${gyb_tool}.py")
+
+  get_filename_component(dir "${GYB_SINGLE_OUTPUT}" DIRECTORY)
+  get_filename_component(basename "${GYB_SINGLE_OUTPUT}" NAME)
+  add_custom_command_target(
+      dependency_target
+      COMMAND
+          "${CMAKE_COMMAND}" -E make_directory "${dir}"
+      COMMAND
+          "${gyb_tool}" "${gyb_flags}"
+          -o "${GYB_SINGLE_OUTPUT}.tmp" "${GYB_SINGLE_SOURCE}"
+      COMMAND
+          "${CMAKE_COMMAND}" -E copy_if_different
+          "${GYB_SINGLE_OUTPUT}.tmp" "${GYB_SINGLE_OUTPUT}"
+      COMMAND
+          "${CMAKE_COMMAND}" -E remove "${GYB_SINGLE_OUTPUT}.tmp"
+      OUTPUT "${GYB_SINGLE_OUTPUT}"
+      DEPENDS "${gyb_tool_source}" "${GYB_SINGLE_DEPENDS}" "${GYB_SINGLE_SOURCE}"
+      COMMENT "Generating ${basename} from ${GYB_SINGLE_SOURCE} ${GYB_SINGLE_COMMENT}"
+      WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"
+      SOURCES "${GYB_SINGLE_SOURCE}"
+      IDEMPOTENT)
+  set("${dependency_out_var_name}" "${dependency_target}" PARENT_SCOPE)
+endfunction()
+
 # Create a target to process .gyb files with the 'gyb' tool.
 #
 # handle_gyb_sources(
@@ -32,16 +100,8 @@ function(handle_gyb_sources dependency_out_var_name sources_var_name arch)
     set(extra_gyb_flags "-DCMAKE_SIZEOF_VOID_P=${ptr_size}")
   endif()
 
-  set(gyb_flags
-      "--test" # Run gyb's self-tests whenever we use it.  They're cheap
-               # enough and it keeps us honest.
-      ${SWIFT_GYB_FLAGS}
-      ${extra_gyb_flags})
-
   set(dependency_targets)
   set(de_gybbed_sources)
-  set(gyb_tool "${SWIFT_SOURCE_DIR}/utils/gyb")
-  set(gyb_tool_source "${gyb_tool}" "${gyb_tool}.py")
   set(gyb_extra_sources
       "${SWIFT_SOURCE_DIR}/utils/GYBUnicodeDataUtils.py"
       "${SWIFT_SOURCE_DIR}/utils/SwiftIntTypes.py"
@@ -59,27 +119,15 @@ function(handle_gyb_sources dependency_out_var_name sources_var_name arch)
       endif()
       set(output_file_name "${dir}/${src_sans_gyb}")
       list(APPEND de_gybbed_sources "${output_file_name}")
-      string(MD5 output_file_name_hash "${output_file_name}")
-      add_custom_command_target(
-          dependency_target
-          COMMAND
-            "${CMAKE_COMMAND}" -E make_directory "${dir}"
-          COMMAND
-            "${gyb_tool}" "${gyb_flags}" -o "${output_file_name}.tmp" "${src}"
-          COMMAND
-            "${CMAKE_COMMAND}" -E copy_if_different "${output_file_name}.tmp" "${output_file_name}"
-          COMMAND
-            "${CMAKE_COMMAND}" -E remove "${output_file_name}.tmp"
+      handle_gyb_source_single(dependency_target
+          SOURCE "${src}"
           OUTPUT "${output_file_name}"
-          DEPENDS "${gyb_tool_source}" "${src}" "${gyb_extra_sources}"
-          COMMENT "Generating ${src_sans_gyb} from ${src} with ptr size = ${ptr_size}"
-          WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"
-          SOURCES "${src}"
-          IDEMPOTENT)
+          FLAGS ${extra_gyb_flags}
+          DEPENDS "${gyb_extra_sources}"
+          COMMENT "with ptr size = ${ptr_size}")
       list(APPEND dependency_targets "${dependency_target}")
     endif()
   endforeach()
   set("${dependency_out_var_name}" "${dependency_targets}" PARENT_SCOPE)
   set("${sources_var_name}" "${de_gybbed_sources}" PARENT_SCOPE)
 endfunction()
-