r259862 - [CMake] Improve the clang order-file generation workflow

[Chris Bieneman via cfe-commits]

Author: cbieneman
Date: Thu Feb  4 19:22:03 2016
New Revision: 259862

URL: http://llvm.org/viewvc/llvm-project?rev=259862&view=rev
Log:
[CMake] Improve the clang order-file generation workflow

Summary:
With this change generating clang order files using dtrace uses the following workflow:

cmake <whatever options you want>

ninja generate-order-file

ninja clang

This patch works by setting a default path to the order file (which can be overridden by the user). If the order file doesn't exist during configuration CMake will create an empty one.

CMake then ties up the dependencies between the clang link job and the order file, and generate-order-file overwrites CLANG_ORDER_FILE with the new order file.

Reviewers: bogner

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D16896

Modified:
    cfe/trunk/CMakeLists.txt
    cfe/trunk/tools/driver/CMakeLists.txt
    cfe/trunk/utils/perf-training/CMakeLists.txt

Modified: cfe/trunk/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/CMakeLists.txt?rev=259862&r1=259861&r2=259862&view=diff
==============================================================================
--- cfe/trunk/CMakeLists.txt (original)
+++ cfe/trunk/CMakeLists.txt Thu Feb  4 19:22:03 2016
@@ -586,9 +586,19 @@ if( CLANG_INCLUDE_DOCS )
   add_subdirectory(docs)
 endif()
 
-set(CLANG_ORDER_FILE "" CACHE FILEPATH
+# this line is needed as a cleanup to ensure that any CMakeCaches with the old
+# default value get updated to the new default.
+if(CLANG_ORDER_FILE STREQUAL "")
+  unset(CLANG_ORDER_FILE CACHE)
+endif()
+
+set(CLANG_ORDER_FILE ${CMAKE_CURRENT_BINARY_DIR}/clang.order CACHE FILEPATH
   "Order file to use when compiling clang in order to improve startup time.")
 
+if(NOT EXISTS ${CLANG_ORDER_FILE})
+  execute_process(COMMAND ${CMAKE_COMMAND} -E touch ${CLANG_ORDER_FILE})
+endif()
+
 if (CLANG_BUILT_STANDALONE OR CMAKE_VERSION VERSION_EQUAL 3 OR
     CMAKE_VERSION VERSION_GREATER 3)
   # Generate a list of CMake library targets so that other CMake projects can

Modified: cfe/trunk/tools/driver/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/tools/driver/CMakeLists.txt?rev=259862&r1=259861&r2=259862&view=diff
==============================================================================
--- cfe/trunk/tools/driver/CMakeLists.txt (original)
+++ cfe/trunk/tools/driver/CMakeLists.txt Thu Feb  4 19:22:03 2016
@@ -87,8 +87,12 @@ if (APPLE)
   set(TOOL_INFO_BUILD_VERSION)
 endif()
 
-if(CLANG_ORDER_FILE)
+check_cxx_compiler_flag("-Wl,-order_file,${CLANG_ORDER_FILE}"
+  LINKER_HAS_ORDER_FILE_FLAG)
+
+if(LINKER_HAS_ORDER_FILE_FLAG)
   target_link_libraries(clang "-Wl,-order_file,${CLANG_ORDER_FILE}")
+  set_target_properties(clang PROPERTIES LINK_DEPENDS ${CLANG_ORDER_FILE})
 endif()
 
 if(WITH_POLLY AND LINK_POLLY_INTO_TOOLS)

Modified: cfe/trunk/utils/perf-training/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/utils/perf-training/CMakeLists.txt?rev=259862&r1=259861&r2=259862&view=diff
==============================================================================
--- cfe/trunk/utils/perf-training/CMakeLists.txt (original)
+++ cfe/trunk/utils/perf-training/CMakeLists.txt Thu Feb  4 19:22:03 2016
@@ -55,9 +55,8 @@ if(DTRACE)
     COMMAND ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/perf-helper.py clean ${CMAKE_CURRENT_BINARY_DIR} dtrace
     COMMENT "Clearing old dtrace data")
 
-
   add_custom_target(generate-order-file
-    COMMAND ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/perf-helper.py gen-order-file --binary $<TARGET_FILE:clang> --output ${CMAKE_CURRENT_BINARY_DIR}/clang.order ${CMAKE_CURRENT_BINARY_DIR}
+    COMMAND ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/perf-helper.py gen-order-file --binary $<TARGET_FILE:clang> --output ${CLANG_ORDER_FILE} ${CMAKE_CURRENT_BINARY_DIR}
     COMMENT "Generating order file"
     DEPENDS generate-dtrace-logs)
 endif()