gecko-dev/build/autoconf/compiler-opts.m4

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dnl This Source Code Form is subject to the terms of the Mozilla Public
dnl License, v. 2.0. If a copy of the MPL was not distributed with this
dnl file, You can obtain one at http://mozilla.org/MPL/2.0/.
dnl Add compiler specific options
AC_DEFUN([MOZ_DEFAULT_COMPILER],
[
dnl Default to MSVC for win32 and gcc-4.2 for darwin
dnl ==============================================================
if test -z "$CROSS_COMPILE"; then
case "$target" in
*-mingw*)
if test -z "$CC"; then CC=cl; fi
if test -z "$CXX"; then CXX=cl; fi
if test -z "$CPP"; then CPP="cl -E -nologo"; fi
if test -z "$CXXCPP"; then CXXCPP="cl -TP -E -nologo"; ac_cv_prog_CXXCPP="$CXXCPP"; fi
if test -z "$LD"; then LD=link; fi
if test -z "$AS"; then
case "${target_cpu}" in
i*86)
AS=ml;
;;
x86_64)
AS=ml64;
;;
esac
fi
if test -z "$MIDL"; then MIDL=midl; fi
# need override this flag since we don't use $(LDFLAGS) for this.
if test -z "$HOST_LDFLAGS" ; then
HOST_LDFLAGS=" "
fi
;;
*-darwin*)
# GCC on darwin is based on gcc 4.2 and we don't support it anymore.
if test -z "$CC"; then
MOZ_PATH_PROGS(CC, clang)
fi
if test -z "$CXX"; then
MOZ_PATH_PROGS(CXX, clang++)
fi
IS_GCC=$($CC -v 2>&1 | grep gcc)
if test -n "$IS_GCC"
then
echo gcc is known to be broken on OS X, please use clang.
echo see http://developer.mozilla.org/en-US/docs/Developer_Guide/Build_Instructions/Mac_OS_X_Prerequisites
echo for more information.
exit 1
fi
;;
esac
fi
])
dnl ============================================================================
dnl C++ rtti
dnl We don't use it in the code, but it can be usefull for debugging, so give
dnl the user the option of enabling it.
dnl ============================================================================
AC_DEFUN([MOZ_RTTI],
[
MOZ_ARG_ENABLE_BOOL(cpp-rtti,
[ --enable-cpp-rtti Enable C++ RTTI ],
[ _MOZ_USE_RTTI=1 ],
[ _MOZ_USE_RTTI= ])
if test -z "$_MOZ_USE_RTTI"; then
if test "$GNU_CC"; then
CXXFLAGS="$CXXFLAGS -fno-rtti"
else
case "$target" in
*-mingw*)
CXXFLAGS="$CXXFLAGS -GR-"
esac
fi
fi
])
dnl A high level macro for selecting compiler options.
AC_DEFUN([MOZ_COMPILER_OPTS],
[
MOZ_RTTI
if test "$CLANG_CXX"; then
## We disable return-type-c-linkage because jsval is defined as a C++ type but is
## returned by C functions. This is possible because we use knowledge about the ABI
## to typedef it to a C type with the same layout when the headers are included
## from C.
##
## mismatched-tags is disabled (bug 780474) mostly because it's useless.
## Worse, it's not supported by gcc, so it will cause tryserver bustage
## without any easy way for non-Clang users to check for it.
_WARNINGS_CXXFLAGS="${_WARNINGS_CXXFLAGS} -Wno-unknown-warning-option -Wno-return-type-c-linkage -Wno-mismatched-tags"
fi
if test "$GNU_CC"; then
CFLAGS="$CFLAGS -ffunction-sections -fdata-sections"
CXXFLAGS="$CXXFLAGS -ffunction-sections -fdata-sections -fno-exceptions"
fi
dnl ========================================================
dnl = Identical Code Folding
dnl ========================================================
MOZ_ARG_DISABLE_BOOL(icf,
[ --disable-icf Disable Identical Code Folding],
MOZ_DISABLE_ICF=1,
MOZ_DISABLE_ICF= )
if test "$GNU_CC" -a "$GCC_USE_GNU_LD" -a -z "$MOZ_DISABLE_ICF"; then
AC_CACHE_CHECK([whether the linker supports Identical Code Folding],
LD_SUPPORTS_ICF,
[echo 'int foo() {return 42;}' \
'int bar() {return 42;}' \
'int main() {return foo() - bar();}' > conftest.${ac_ext}
# If the linker supports ICF, foo and bar symbols will have
# the same address
if AC_TRY_COMMAND([${CC-cc} -o conftest${ac_exeext} $LDFLAGS -Wl,--icf=safe -ffunction-sections conftest.${ac_ext} $LIBS 1>&2]) &&
test -s conftest${ac_exeext} &&
objdump -t conftest${ac_exeext} | awk changequote(<<, >>)'{a[<<$>>6] = <<$>>1} END {if (a["foo"] && (a["foo"] != a["bar"])) { exit 1 }}'changequote([, ]); then
LD_SUPPORTS_ICF=yes
else
LD_SUPPORTS_ICF=no
fi
rm -rf conftest*])
if test "$LD_SUPPORTS_ICF" = yes; then
_SAVE_LDFLAGS="$LDFLAGS -Wl,--icf=safe"
LDFLAGS="$LDFLAGS -Wl,--icf=safe -Wl,--print-icf-sections"
AC_TRY_LINK([], [],
[LD_PRINT_ICF_SECTIONS=-Wl,--print-icf-sections],
[LD_PRINT_ICF_SECTIONS=])
AC_SUBST([LD_PRINT_ICF_SECTIONS])
LDFLAGS="$_SAVE_LDFLAGS"
fi
fi
dnl ========================================================
dnl = Automatically remove dead symbols
dnl ========================================================
if test "$GNU_CC" -a "$GCC_USE_GNU_LD" -a -n "$MOZ_DEBUG_FLAGS"; then
dnl See bug 670659
AC_CACHE_CHECK([whether removing dead symbols breaks debugging],
GC_SECTIONS_BREAKS_DEBUG_RANGES,
[echo 'int foo() {return 42;}' \
'int bar() {return 1;}' \
'int main() {return foo();}' > conftest.${ac_ext}
if AC_TRY_COMMAND([${CC-cc} -o conftest.${ac_objext} $CFLAGS $MOZ_DEBUG_FLAGS -c conftest.${ac_ext} 1>&2]) &&
AC_TRY_COMMAND([${CC-cc} -o conftest${ac_exeext} $LDFLAGS $MOZ_DEBUG_FLAGS -Wl,--gc-sections conftest.${ac_objext} $LIBS 1>&2]) &&
test -s conftest${ac_exeext} -a -s conftest.${ac_objext}; then
if test "`$PYTHON "$_topsrcdir"/build/autoconf/check_debug_ranges.py conftest.${ac_objext} conftest.${ac_ext}`" = \
"`$PYTHON "$_topsrcdir"/build/autoconf/check_debug_ranges.py conftest${ac_exeext} conftest.${ac_ext}`"; then
GC_SECTIONS_BREAKS_DEBUG_RANGES=no
else
GC_SECTIONS_BREAKS_DEBUG_RANGES=yes
fi
else
dnl We really don't expect to get here, but just in case
GC_SECTIONS_BREAKS_DEBUG_RANGES="no, but it's broken in some other way"
fi
rm -rf conftest*])
if test "$GC_SECTIONS_BREAKS_DEBUG_RANGES" = no; then
DSO_LDOPTS="$DSO_LDOPTS -Wl,--gc-sections"
fi
fi
])
dnl GCC and clang will fail if given an unknown warning option like -Wfoobar.
dnl But later versions won't fail if given an unknown negated warning option
dnl like -Wno-foobar. So when we are check for support of negated warning
dnl options, we actually test the positive form, but add the negated form to
dnl the flags variable.
AC_DEFUN([MOZ_C_SUPPORTS_WARNING],
[
AC_CACHE_CHECK(whether the C compiler supports $1$2, $3,
[
AC_LANG_SAVE
AC_LANG_C
_SAVE_CFLAGS="$CFLAGS"
CFLAGS="$CFLAGS -Werror -W$2"
AC_TRY_COMPILE([],
[return(0);],
$3="yes",
$3="no")
CFLAGS="$_SAVE_CFLAGS"
AC_LANG_RESTORE
])
if test "${$3}" = "yes"; then
_WARNINGS_CFLAGS="${_WARNINGS_CFLAGS} $1$2"
fi
])
AC_DEFUN([MOZ_CXX_SUPPORTS_WARNING],
[
AC_CACHE_CHECK(whether the C++ compiler supports $1$2, $3,
[
AC_LANG_SAVE
AC_LANG_CPLUSPLUS
_SAVE_CXXFLAGS="$CXXFLAGS"
CXXFLAGS="$CXXFLAGS -Werror -W$2"
AC_TRY_COMPILE([],
[return(0);],
$3="yes",
$3="no")
CXXFLAGS="$_SAVE_CXXFLAGS"
AC_LANG_RESTORE
])
if test "${$3}" = "yes"; then
_WARNINGS_CXXFLAGS="${_WARNINGS_CXXFLAGS} $1$2"
fi
])