[llvm] r234159 - Don't use -ffunction-sections -fdata-sections on debug builds.

[Rafael Espindola]

Author: rafael
Date: Mon Apr  6 09:34:43 2015
New Revision: 234159

URL: http://llvm.org/viewvc/llvm-project?rev=234159&view=rev
Log:
Don't use -ffunction-sections -fdata-sections on debug builds.

Unfortunately, on ELF there is not used attribute on the .o files,
so there is no easy way to keep the dump function alive.

If we are not gcing, we may as well produce non gcable files and
avoid the cost.

Linking a debug clang now takes 18.856225992 seconds, before it
took 21.206897447.

I will try avoiding --gc-sections -O3 on a followup patch.

Modified:
    llvm/trunk/cmake/modules/HandleLLVMOptions.cmake

Modified: llvm/trunk/cmake/modules/HandleLLVMOptions.cmake
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/cmake/modules/HandleLLVMOptions.cmake?rev=234159&r1=234158&r2=234159&view=diff
==============================================================================
--- llvm/trunk/cmake/modules/HandleLLVMOptions.cmake (original)
+++ llvm/trunk/cmake/modules/HandleLLVMOptions.cmake Mon Apr  6 09:34:43 2015
@@ -486,7 +486,8 @@ endif()
 # But MinSizeRel seems to add that automatically, so maybe disable these
 # flags instead if LLVM_NO_DEAD_STRIP is set.
 if(NOT CYGWIN AND NOT WIN32)
-  if(NOT ${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
+  if(NOT ${CMAKE_SYSTEM_NAME} MATCHES "Darwin" AND
+     NOT uppercase_CMAKE_BUILD_TYPE STREQUAL "DEBUG")
     check_c_compiler_flag("-Werror -fno-function-sections" C_SUPPORTS_FNO_FUNCTION_SECTIONS)
     if (C_SUPPORTS_FNO_FUNCTION_SECTIONS)
       # Don't add -ffunction-section if it can be disabled with -fno-function-sections.