diff options
| -rw-r--r-- | gcc/ChangeLog | 8 | ||||
| -rw-r--r-- | gcc/Makefile.in | 5 | ||||
| -rwxr-xr-x | gcc/configure | 41 | ||||
| -rw-r--r-- | gcc/configure.ac | 26 |
4 files changed, 77 insertions, 3 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index abf05a6..42b03ce 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,11 @@ +2015-08-03 Ulrich Weigand <Ulrich.Weigand@de.ibm.com> + + * configure.ac: Set aliasing_flags to -fno-strict-aliasing if + the host compiler is affected by placement new aliasing bug. + * configure: Regenerate. + * Makefile.in (ALIASING_FLAGS): New variable. + (ALL_CXXFLAGS): Add $(ALIASING_FLAGS). + 2015-08-03 Szabolcs Nagy <szabolcs.nagy@arm.com> PR target/66731 diff --git a/gcc/Makefile.in b/gcc/Makefile.in index be259e8..36168af 100644 --- a/gcc/Makefile.in +++ b/gcc/Makefile.in @@ -180,6 +180,8 @@ NOCOMMON_FLAG = @nocommon_flag@ NOEXCEPTION_FLAGS = @noexception_flags@ +ALIASING_FLAGS = @aliasing_flags@ + # This is set by --disable-maintainer-mode (default) to "#" # FIXME: 'MAINT' will always be set to an empty string, no matter if # --disable-maintainer-mode is used or not. This is because the @@ -986,7 +988,8 @@ ALL_CFLAGS = $(T_CFLAGS) $(CFLAGS-$@) \ # The C++ version. ALL_CXXFLAGS = $(T_CFLAGS) $(CFLAGS-$@) $(CXXFLAGS) $(INTERNAL_CFLAGS) \ - $(COVERAGE_FLAGS) $(NOEXCEPTION_FLAGS) $(WARN_CXXFLAGS) @DEFS@ + $(COVERAGE_FLAGS) $(ALIASING_FLAGS) $(NOEXCEPTION_FLAGS) \ + $(WARN_CXXFLAGS) @DEFS@ # Likewise. Put INCLUDES at the beginning: this way, if some autoconf macro # puts -I options in CPPFLAGS, our include files in the srcdir will always diff --git a/gcc/configure b/gcc/configure index c8928d8..271316a 100755 --- a/gcc/configure +++ b/gcc/configure @@ -789,6 +789,7 @@ c_strict_warn strict_warn c_loose_warn loose_warn +aliasing_flags CPP EGREP GREP @@ -6526,6 +6527,42 @@ fi rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext fi +# Check whether compiler is affected by placement new aliasing bug (PR 29286). +# If the host compiler is affected by the bug, and we build with optimization +# enabled (which happens e.g. when cross-compiling), the pool allocator may +# get miscompiled. Use -fno-strict-aliasing to work around this problem. +# Since there is no reliable feature check for the presence of this bug, +# we simply use a GCC version number check. (This should never trigger for +# stages 2 or 3 of a native bootstrap.) +aliasing_flags= +if test "$GCC" = yes; then + saved_CXXFLAGS="$CXXFLAGS" + + # The following test compilation will succeed if and only if $CXX accepts + # -fno-strict-aliasing *and* is older than GCC 4.3. + CXXFLAGS="$CXXFLAGS -fno-strict-aliasing" + { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CXX is affected by placement new aliasing bug" >&5 +$as_echo_n "checking whether $CXX is affected by placement new aliasing bug... " >&6; } + cat confdefs.h - <<_ACEOF >conftest.$ac_ext +/* end confdefs.h. */ + +#if (__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3) +#error compiler not affected by placement new aliasing bug +#endif + +_ACEOF +if ac_fn_cxx_try_compile "$LINENO"; then : + { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5 +$as_echo "yes" >&6; }; aliasing_flags='-fno-strict-aliasing' +else + { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5 +$as_echo "no" >&6; } +fi +rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext + + CXXFLAGS="$saved_CXXFLAGS" +fi + @@ -18301,7 +18338,7 @@ else lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2 lt_status=$lt_dlunknown cat > conftest.$ac_ext <<_LT_EOF -#line 18304 "configure" +#line 18341 "configure" #include "confdefs.h" #if HAVE_DLFCN_H @@ -18407,7 +18444,7 @@ else lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2 lt_status=$lt_dlunknown cat > conftest.$ac_ext <<_LT_EOF -#line 18410 "configure" +#line 18447 "configure" #include "confdefs.h" #if HAVE_DLFCN_H diff --git a/gcc/configure.ac b/gcc/configure.ac index a192ad9..767e288 100644 --- a/gcc/configure.ac +++ b/gcc/configure.ac @@ -416,6 +416,32 @@ struct X<long long> { typedef long long t; }; ]], [[X<int64_t>::t x;]])],[],[AC_MSG_ERROR([error verifying int64_t uses long long])]) fi +# Check whether compiler is affected by placement new aliasing bug (PR 29286). +# If the host compiler is affected by the bug, and we build with optimization +# enabled (which happens e.g. when cross-compiling), the pool allocator may +# get miscompiled. Use -fno-strict-aliasing to work around this problem. +# Since there is no reliable feature check for the presence of this bug, +# we simply use a GCC version number check. (This should never trigger for +# stages 2 or 3 of a native bootstrap.) +aliasing_flags= +if test "$GCC" = yes; then + saved_CXXFLAGS="$CXXFLAGS" + + # The following test compilation will succeed if and only if $CXX accepts + # -fno-strict-aliasing *and* is older than GCC 4.3. + CXXFLAGS="$CXXFLAGS -fno-strict-aliasing" + AC_MSG_CHECKING([whether $CXX is affected by placement new aliasing bug]) + AC_COMPILE_IFELSE([ +#if (__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3) +#error compiler not affected by placement new aliasing bug +#endif +], + [AC_MSG_RESULT([yes]); aliasing_flags='-fno-strict-aliasing'], + [AC_MSG_RESULT([no])]) + + CXXFLAGS="$saved_CXXFLAGS" +fi +AC_SUBST(aliasing_flags) |