# gcc configuration options config CC_PKGVERSION string prompt "gcc ID string" depends on CC_GCC_4_3_or_later default "crosstool-NG-${CT_VERSION}" help Specify a string that identifies your package. You may wish to include a build number or build date. This version string will be included in the output of gcc --version. This is passed to the configure flag --with-pkgversion. config CC_BUGURL string prompt "gcc bug URL" depends on CC_GCC_4_3_or_later default "" help Specify the URL that users should visit if they wish to report a bug. config CC_ENABLE_CXX_FLAGS string prompt "Flags to pass to --enable-cxx-flags" default "" help Enter here the value of the gcc's ./configure option --enable-cxx-flags. Leave empty if you don't know better. Note: just pass in the option _value_, that is only the part that goes after the '=' sign. config CC_CORE_EXTRA_CONFIG string prompt "Core gcc extra config" default "" help Extra flags to pass onto ./configure when configuring the core gcc. The core gcc is a stripped down, C-only compiler needed to build the C library. Kinda bootstrap gcc, if you wish. config CC_EXTRA_CONFIG string prompt "gcc extra config" default "" depends on ! BARE_METAL help Extra flags to pass onto ./configure when configuring gcc. config STATIC_TOOLCHAIN select CC_STATIC_LIBSTDCXX if CC_GCC_4_4_or_later config CC_STATIC_LIBSTDCXX bool prompt "Link libstdc++ statically into the gcc binary" default y depends on CC_GCC_4_4_or_later help Newer gcc versions use the PPL library which is C++ code. Statically linking libstdc++ increases the likeliness that the gcc binary will run on machines other than the one which it was built on, without having to worry about distributing the matching version of libstdc++ along with it. #----------------------------------------------------------------------------- # Optimisation features comment "Optimisation features" config CC_GCC_USE_GRAPHITE bool prompt "Enable GRAPHITE loop optimisations" default y depends on CC_GCC_HAS_GRAPHITE select CC_GCC_USE_PPL_CLOOG help Enable the GRAPHITE loop optimsations. This requires the PPL and CLooG companion libraries, and those will be automatically build for you. On some systems (eg. Cygwin), PPL and/or CLooG may not build properly (yet), so you'll have to say 'N' here. # The way LTO works is a bit twisted. # See: http://gcc.gnu.org/wiki/LinkTimeOptimization#Requirements # Basically: # - if binutils has plugins: LTO is handled by ld/gold by loading # the plugin when linking # - if binutils does not have plugins: LTO is handled by collect2 # In any case, LTO support does not depend on plugins, but takes # advantage of it # Also, only the 4.5 series needs libelf for LTO; 4.6 has dropped # the dependency. config CC_GCC_USE_LTO bool prompt "Enable LTO" default y depends on CC_GCC_HAS_LTO select CC_GCC_USE_LIBELF if CC_GCC_4_5 help Enable the Link Time Optimisations. This will require the libelf companion library, and it wil be build automatically for you. #----------------------------------------------------------------------------- comment "Settings for libraries running on target" config CC_GCC_ENABLE_TARGET_OPTSPACE bool prompt "Optimize gcc libs for size" default y help Pass --enable-target-optspace to crossgcc's configure. This will compile crossgcc's libs with -Os. config CC_GCC_LIBMUDFLAP bool prompt "Compile libmudflap" default n help libmudflap is a pointer-use checking tool, which can detect various mis-usages of pointers in C and (to some extents) C++. You should say 'N' here, as libmduflap generates instrumented code (thus it is a bit bigger and a bit slower) and requires re-compilation and re-link, while it exists better run-time alternatives (eg. DUMA, dmalloc...) that need neither re- compilation nor re-link. config CC_GCC_LIBGOMP bool prompt "Compile libgomp" default n help libgomp is "the GNU implementation of the OpenMP Application Programming Interface (API) for multi-platform shared-memory parallel programming in C/C++ and Fortran". See: http://gcc.gnu.org/onlinedocs/libgomp/ The default is 'N'. Say 'Y' if you need it, and report success/failure. config CC_GCC_LIBSSP bool prompt "Compile libssp" default n help libssp is the run-time Stack-Smashing Protection library. The default is 'N'. Say 'Y' if you need it, and report success/failure. #----------------------------------------------------------------------------- comment "Misc. obscure options." config CC_CXA_ATEXIT bool prompt "Use __cxa_atexit" default y depends on ! BARE_METAL help If you get the missing symbol "__cxa_atexit" when building C++ programs, you might want to try disabling this option. config CC_GCC_DISABLE_PCH bool prompt "Do not build PCH" default n help Say 'y' here to not use Pre-Compiled Headers in the resulting toolchain. at the expense of speed when compiling C++ code. For some configurations (most notably canadian?), PCH are broken, and need to be disabled. Please see: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40974 config CC_GCC_SJLJ_EXCEPTIONS tristate prompt "Use sjlj for exceptions" depends on ! BARE_METAL default m help 'sjlj' is short for setjmp/longjmp. On some architectures, stack unwinding during exception handling works perfectly well without using sjlj, while on some others, use of sjlj is required for proper stack unwinding. Option | sjlj use | Associated ./configure switch ---------+--------------------+-------------------------------- Y | forcibly used | --enable-sjlj-exceptions M | auto | (none, ./configure decides) N | forcibly not used | --disable-sjlj-exceptions It should be safe to say 'M' or 'N'. It can happen that ./configure is wrong in some cases. Known case is for ARM big endian, where you should say 'N'. config CC_GCC_LDBL_128 tristate prompt "Enable 128-bit long doubles" default m depends on CC_GCC_4_2_or_later help Saying 'Y' will force gcc to use 128-bit wide long doubles Saying 'N' will force gcc to use 64-bit wide long doubles Saying 'M' will let gcc choose (default is 128-bit for glibc >= 2.4, 64-bit otherwise) If in doubt, keep the default, ie. 'M'.