config/cc/gcc.in.2
author "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
Fri Oct 08 23:53:41 2010 +0200 (2010-10-08)
changeset 2144 80f088eb0608
parent 2143 c7126e94e286
child 2145 efea409ff8be
permissions -rw-r--r--
cc/gcc: shuffle config knobs

It makes sense to have all library-related config knobs in
the same place; and it makes sense to have all other misc
config knobs in the same other place.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
     1 # Misc library-related options
     2 
     3 config CC_GCC_ENABLE_TARGET_OPTSPACE
     4     bool
     5     prompt "Optimize gcc libs for size"
     6     default y
     7     help
     8       Pass --enable-target-optspace to crossgcc's configure.
     9       
    10       This will compile crossgcc's libs with -Os.
    11 
    12 config CC_GCC_USE_GRAPHITE
    13     bool
    14     prompt "Enable GRAPHITE loop optimisations"
    15     default y
    16     depends on CC_GCC_HAS_GRAPHITE
    17     select CC_GCC_USE_PPL_CLOOG
    18     help
    19       Enable the GRAPHITE loop optimsations.
    20       
    21       This requires the PPL and CLooG companion libraries, and
    22       those will be automatically build for you.
    23       
    24       On some systems (eg. Cygwin), PPL and/or CLooG may not
    25       build properly (yet), so you'll have to say 'N' here.
    26 
    27 config CC_GCC_USE_LTO
    28     bool
    29     prompt "Enable LTO"
    30     default y
    31     depends on CC_GCC_HAS_LTO
    32     select CC_GCC_USE_LIBELF
    33     help
    34       Enable the Link Time Optimisations.
    35       
    36       This will require the libelf companion library, and it
    37       wil be build automatically for you.
    38 
    39 config CC_STATIC_LIBSTDCXX
    40     bool
    41     prompt "Link libstdc++ statically into the gcc binary"
    42     default y
    43     depends on CC_GCC_4_4_or_later
    44     help
    45       Newer gcc versions use the PPL library which is C++ code.  Statically
    46       linking libstdc++ increases the likeliness that the gcc binary will
    47       run on machines other than the one which it was built on, without
    48       having to worry about distributing the matching version of libstdc++
    49       along with it.
    50 
    51 config CC_GCC_LIBMUDFLAP
    52     bool
    53     prompt "Compile libmudflap"
    54     default n
    55     help
    56       libmudflap is a pointer-use checking tool, which can detect
    57       various mis-usages of pointers in C and (to some extents) C++.
    58       
    59       You should say 'N' here, as libmduflap generates instrumented
    60       code (thus it is a bit bigger and a bit slower) and requires
    61       re-compilation and re-link, while it exists better run-time
    62       alternatives (eg. DUMA, dmalloc...) that need neither re-
    63       compilation nor re-link.
    64 
    65 #-----------------------------------------------------------------------------
    66 
    67 comment "Misc. obscure options."
    68 
    69 config CC_CXA_ATEXIT
    70     bool
    71     prompt "Use __cxa_atexit"
    72     default y
    73     depends on ! BARE_METAL
    74     help
    75       If you get the missing symbol "__cxa_atexit" when building C++ programs,
    76       you might want to try disabling this option.
    77 
    78 config CC_GCC_DISABLE_PCH
    79     bool
    80     prompt "Do not build PCH"
    81     default n
    82     help
    83       Say 'y' here to not use Pre-Compiled Headers in the resulting toolchain.
    84       at the expense of speed when compiling C++ code.
    85       
    86       For some configurations (most notably canadian?), PCH are broken, and
    87       need to be disabled. Please see:
    88         http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40974
    89 
    90 config CC_GCC_SJLJ_EXCEPTIONS
    91     tristate
    92     prompt "Use sjlj for exceptions"
    93     depends on ! BARE_METAL
    94     default m
    95     help
    96       'sjlj' is short for setjmp/longjmp.
    97       
    98       On some architectures, stack unwinding during exception handling
    99       works perfectly well without using sjlj, while on some others,
   100       use of sjlj is required for proper stack unwinding.
   101       
   102        Option  | sjlj use           | Associated ./configure switch
   103       ---------+--------------------+--------------------------------
   104          Y     | forcibly used      | --enable-sjlj-exceptions
   105          M     | auto               | (none, ./configure decides)
   106          N     | forcibly not used  | --disable-sjlj-exceptions
   107       
   108       It should be safe to say 'M' or 'N'.
   109       
   110       It can happen that ./configure is wrong in some cases. Known
   111       case is for ARM big endian, where you should say 'N'.
   112 
   113 config CC_GCC_LDBL_128
   114     tristate
   115     prompt "Enable 128-bit long doubles"
   116     default m
   117     depends on CC_GCC_4_2_or_later
   118     help
   119       Saying 'Y' will force gcc to use 128-bit wide long doubles
   120       Saying 'N' will force gcc to use 64-bit wide long doubles
   121       Saying 'M' will let gcc choose (default is 128-bit for
   122                  glibc >= 2.4, 64-bit otherwise)
   123       
   124       If in doubt, keep the default, ie. 'M'.