# Copyright (c) 2010, 2014, Oracle and/or its affiliates. All rights reserved.
# 
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA 

# This file includes Linux specific options and quirks, related to system checks

INCLUDE(CheckSymbolExists)
INCLUDE(CheckCSourceRuns)

# We require at least GCC 4.4 or Clang 3.3.
IF(NOT FORCE_UNSUPPORTED_COMPILER)
  IF(CMAKE_COMPILER_IS_GNUCC)
    EXECUTE_PROCESS(COMMAND ${CMAKE_C_COMPILER} -dumpversion
                    OUTPUT_VARIABLE GCC_VERSION)
    IF(GCC_VERSION VERSION_LESS 4.4)
      MESSAGE(FATAL_ERROR "GCC 4.4 or newer is required!")
    ENDIF()
  ELSEIF(CMAKE_C_COMPILER_ID MATCHES "Clang")
    CHECK_C_SOURCE_RUNS("
      int main()
      {
        return (__clang_major__ < 3) ||
               (__clang_major__ == 3 && __clang_minor__ < 3);
      }" HAVE_SUPPORTED_CLANG_VERSION)
    IF(NOT HAVE_SUPPORTED_CLANG_VERSION)
      MESSAGE(FATAL_ERROR "Clang 3.3 or newer is required!")
    ENDIF()
  ELSE()
    MESSAGE(FATAL_ERROR "Unsupported compiler!")
  ENDIF()
ENDIF()

# ISO C89, ISO C99, POSIX.1, POSIX.2, BSD, SVID, X/Open, LFS, and GNU extensions.
ADD_DEFINITIONS(-D_GNU_SOURCE)

# 64 bit file offset support flag
ADD_DEFINITIONS(-D_FILE_OFFSET_BITS=64)

# Fix CMake (< 2.8) flags. -rdynamic exports too many symbols.
FOREACH(LANG C CXX)
  STRING(REPLACE "-rdynamic" "" 
  CMAKE_SHARED_LIBRARY_LINK_${LANG}_FLAGS
  ${CMAKE_SHARED_LIBRARY_LINK_${LANG}_FLAGS}  
  )
ENDFOREACH()

# Ensure we have clean build for shared libraries
# without unresolved symbols
# Not supported with Sanitizers
IF(NOT WITH_ASAN AND NOT WITH_MSAN AND NOT WITH_UBSAN)
  SET(LINK_FLAG_NO_UNDEFINED "-Wl,--no-undefined")
ENDIF()

# Linux specific HUGETLB /large page support
CHECK_SYMBOL_EXISTS(SHM_HUGETLB sys/shm.h HAVE_LINUX_LARGE_PAGES)