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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
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],
[
if test -z "$_MOZ_USE_RTTI"; then
if test "$GNU_CC"; then
CXXFLAGS="$CXXFLAGS -fno-rtti"
else
case "$target" in
*-mingw*)
CXXFLAGS="$CXXFLAGS -GR-"
esac
fi
fi
])
dnl ========================================================
dnl =
dnl = Debugging Options
dnl =
dnl ========================================================
AC_DEFUN([MOZ_DEBUGGING_OPTS],
[
if test -z "$MOZ_DEBUG" -o -n "$MOZ_ASAN"; then
MOZ_NO_DEBUG_RTL=1
fi
AC_SUBST(MOZ_NO_DEBUG_RTL)
if test -n "$MOZ_DEBUG"; then
if test -n "$COMPILE_ENVIRONMENT"; then
AC_MSG_CHECKING([for valid debug flags])
_SAVE_CFLAGS=$CFLAGS
CFLAGS="$CFLAGS $MOZ_DEBUG_FLAGS"
AC_TRY_COMPILE([#include <stdio.h>],
[printf("Hello World\n");],
_results=yes,
_results=no)
AC_MSG_RESULT([$_results])
if test "$_results" = "no"; then
AC_MSG_ERROR([These compiler flags are invalid: $MOZ_DEBUG_FLAGS])
fi
CFLAGS=$_SAVE_CFLAGS
fi
fi
])
dnl A high level macro for selecting compiler options.
AC_DEFUN([MOZ_COMPILER_OPTS],
[
MOZ_DEBUGGING_OPTS
MOZ_RTTI
if test "$GNU_CC"; then
if test -z "$DEVELOPER_OPTIONS"; then
CFLAGS="$CFLAGS -ffunction-sections -fdata-sections"
CXXFLAGS="$CXXFLAGS -ffunction-sections -fdata-sections"
fi
CFLAGS="$CFLAGS -fno-math-errno"
CXXFLAGS="$CXXFLAGS -fno-exceptions -fno-math-errno"
fi
dnl ========================================================
dnl = Identical Code Folding
dnl ========================================================
if test "$GNU_CC" -a "$GCC_USE_GNU_LD" -a -z "$MOZ_DISABLE_ICF" -a -z "$DEVELOPER_OPTIONS"; 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} &&
$LLVM_OBJDUMP -t conftest${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 ========================================================
SANCOV=
if test -n "$LIBFUZZER"; then
case "$LIBFUZZER_FLAGS" in
*-fsanitize-coverage*|*-fsanitize=fuzzer*)
SANCOV=1
;;
esac
fi
if test "$GNU_CC" -a "$GCC_USE_GNU_LD" -a -z "$DEVELOPER_OPTIONS" -a -z "$MOZ_PROFILE_GENERATE" -a -z "$SANCOV"; then
if test -n "$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.${ac_objext}; then
if test "`$PYTHON3 -m mozbuild.configure.check_debug_ranges conftest.${ac_objext} conftest.${ac_ext}`" = \
"`$PYTHON3 -m mozbuild.configure.check_debug_ranges conftest${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="$DSO_LDOPTS -Wl,--gc-sections"
fi
else
DSO_LDOPTS="$DSO_LDOPTS -Wl,--gc-sections"
fi
fi
if test "$GNU_CC$CLANG_CC"; then
MOZ_PROGRAM_LDFLAGS="$MOZ_PROGRAM_LDFLAGS -pie"
fi
AC_SUBST(MOZ_PROGRAM_LDFLAGS)
dnl ASan assumes no symbols are being interposed, and when that happens,
dnl it's not happy with it. Unconveniently, since Firefox is exporting
dnl libffi symbols and Gtk+3 pulls system libffi via libwayland-client,
dnl system libffi interposes libffi symbols that ASan assumes are in
dnl libxul, so it barfs about buffer overflows.
dnl Using -Wl,-Bsymbolic ensures no exported symbol can be interposed.
if test -n "$GCC_USE_GNU_LD"; then
case "$LDFLAGS" in
*-fsanitize=address*)
LDFLAGS="$LDFLAGS -Wl,-Bsymbolic"
;;
esac
fi
])
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