ENDBR32 and RDSSPD are multi-byte NOPs on x86-64 processors and
newer x86 processors, starting Pentium Pro. They are UD on older
32-bit processors. Detect this at configure time and adjust the
default value for enable_cet. GCC will enable CET in 32-bit run-time
libraries in any case if --enable-cet is used to configure GCC.
PR target/84148
* config/cet.m4: Check if target support multi-byte NOPS (SSE).
* libatomic/configure: Regenerate.
* libbacktrace/configure: Likewise.
* libgcc/configure: Likewise.
* libgfortran/configure: Likewise.
* libgomp/configure: Likewise.
* libitm/configure: Likewise.
* libmpx/configure: Likewise.
* libobjc/configure: Likewise.
* libquadmath/configure: Likewise.
* libsanitizer/configure: Likewise.
* libssp/configure: Likewise.
* libstdc++-v3/configure: Likewise.
* libvtv/configure: Likewise.
From-SVN: r257809
Enable building libgcc with CET options by default on Linux/x86 if
binutils supports CET v2.0. It can be disabled with --disable-cet.
It is an error to configure GCC with --enable-cet if bintuiils
doesn't support CET v2.0.
ENDBR instruction is added to __morestack_large_model since it is
called indirectly.
2017-11-17 Igor Tsimbalist <igor.v.tsimbalist@intel.com>
config/
* cet.m4: New file.
gcc/
* config.gcc (extra_headers): Add cet.h for x86 targets.
* config/i386/cet.h: New file.
* doc/install.texi: Add --enable-cet/--disable-cet.
libgcc/
* Makefile.in (configure_deps): Add $(srcdir)/../config/cet.m4.
(CET_FLAGS): New.
* config/i386/morestack.S: Include <cet.h>.
(__morestack_large_model): Add _CET_ENDBR at function entrance.
* config/i386/resms64.h: Include <cet.h>.
* config/i386/resms64f.h: Likewise.
* config/i386/resms64fx.h: Likewise.
* config/i386/resms64x.h: Likewise.
* config/i386/savms64.h: Likewise.
* config/i386/savms64f.h: Likewise.
* config/i386/t-linux (HOST_LIBGCC2_CFLAGS): Add $(CET_FLAGS).
(CRTSTUFF_T_CFLAGS): Likewise.
* configure.ac: Include ../config/cet.m4.
Set and substitute CET_FLAGS.
* configure: Regenerated.
From-SVN: r254868
Igor Tsimbalist