https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85417
--- Comment #6 from hjl at gcc dot gnu.org <hjl at gcc dot gnu.org> --- Author: hjl Date: Thu Apr 19 15:15:04 2018 New Revision: 259496 URL: https://gcc.gnu.org/viewcvs?rev=259496&root=gcc&view=rev Log: x86: Enable -fcf-protection with multi-byte NOPs -fcf-protection -mcet can't be used with IFUNC features, like symbol multiversioning or target clone, since IBT/SHSTK are applied to the whole program and they may be disabled in some functions. But -fcf-protection is implemented with multi-byte NOPs on all 64-bit processors as well as 32-bit processors starting with Pentium Pro. If -fcf-protection requires -mcet, IFUNC features can't be used on Linux when -fcf-protection is enabled by default. This patch changes -fcf-protection to implement indirect branch and return address tracking with multi-byte NOPs. -mibt and -mshstk are changed to only enable CET built-in functions. CET tests are updated to allow -fcf-protection without -mibt, -mshstk and -mcet on x86. -fcf-protection=none are also added to tests which fail with -fcf-protection so that -fcf-protection can be added to RUNTESTFLAGS to verify -fcf-protection implementation. gcc/ PR target/85417 * config/i386/cet.c (file_end_indicate_exec_stack_and_cet): Check flag_cf_protection instead of TARGET_IBT and TARGET_SHSTK. * config/i386/i386-c.c (ix86_target_macros_internal): Also define __IBT__ and __SHSTK__ for -fcf-protection. * config/i386/i386.c (pass_insert_endbranch::gate): Don't check TARGET_IBT. (ix86_trampoline_init): Likewise. (x86_output_mi_thunk): Likewise. (ix86_notrack_prefixed_insn_p): Likewise. (ix86_option_override_internal): Don't disallow -fcf-protection. * config/i386/i386.md (rdssp<mode>): Also enable for -fcf-protection. (incssp<mode>): Likewise. (nop_endbr): Likewise. * config/i386/i386.opt (mcet): Change help message to built-in functions only. (mibt): Likewise. (mshstk): Likewise. * doc/invoke.texi: Remove -mcet, -mibt and -mshstk condition on -fcf-protection. Change -mcet, -mibt and -mshstk to only enable CET built-in functions. gcc/testsuite/ PR target/85417 * c-c++-common/attr-nocf-check-1.c: Compile with -fcf-protection=none. * c-c++-common/attr-nocf-check-3.c: Likewise. * gcc.dg/march-generic.c: Likewise. * gcc.target/i386/align-limit.c: Likewise. * gcc.target/i386/cet-notrack-icf-1.c: Likewise. * gcc.target/i386/cet-notrack-icf-3.c: Likewise. * gcc.target/i386/cet-property-2.c: Likewise. * gcc.target/i386/ret-thunk-26.c: Likewise. * c-c++-common/fcf-protection-1.c: Remove dg-error for x86 targets. * c-c++-common/fcf-protection-2.c: Likewise. * c-c++-common/fcf-protection-3.c: Likewise. * c-c++-common/fcf-protection-5.c: Likewise. * c-c++-common/fcf-protection-6.c: Likewise. * c-c++-common/fcf-protection-7.c: Likewise. * gcc.target/i386/cet-label-3.c: New test. * gcc.target/i386/cet-property-3.c: Likewise. * gcc.target/i386/cet-sjlj-7.c: Likewise. * gcc.target/i386/pr85417-1.c: Likewise. * gcc.target/i386/indirect-thunk-attr-7.c: Also expect __x86_indirect_thunk_nt_(r|e)ax * gcc.target/i386/indirect-thunk-extern-7.c: Likewise. * gcc.target/i386/pr85403.c: Remove dg-error, Added: trunk/gcc/testsuite/gcc.target/i386/cet-label-3.c trunk/gcc/testsuite/gcc.target/i386/cet-property-3.c trunk/gcc/testsuite/gcc.target/i386/cet-sjlj-7.c trunk/gcc/testsuite/gcc.target/i386/pr85417-1.c Modified: trunk/gcc/ChangeLog trunk/gcc/config/i386/cet.c trunk/gcc/config/i386/i386-c.c trunk/gcc/config/i386/i386.c trunk/gcc/config/i386/i386.md trunk/gcc/config/i386/i386.opt trunk/gcc/doc/invoke.texi trunk/gcc/testsuite/ChangeLog trunk/gcc/testsuite/c-c++-common/attr-nocf-check-1.c trunk/gcc/testsuite/c-c++-common/attr-nocf-check-3.c trunk/gcc/testsuite/c-c++-common/fcf-protection-1.c trunk/gcc/testsuite/c-c++-common/fcf-protection-2.c trunk/gcc/testsuite/c-c++-common/fcf-protection-3.c trunk/gcc/testsuite/c-c++-common/fcf-protection-5.c trunk/gcc/testsuite/c-c++-common/fcf-protection-6.c trunk/gcc/testsuite/c-c++-common/fcf-protection-7.c trunk/gcc/testsuite/gcc.dg/march-generic.c trunk/gcc/testsuite/gcc.target/i386/align-limit.c trunk/gcc/testsuite/gcc.target/i386/cet-notrack-icf-1.c trunk/gcc/testsuite/gcc.target/i386/cet-notrack-icf-3.c trunk/gcc/testsuite/gcc.target/i386/cet-property-2.c trunk/gcc/testsuite/gcc.target/i386/indirect-thunk-attr-7.c trunk/gcc/testsuite/gcc.target/i386/indirect-thunk-extern-7.c trunk/gcc/testsuite/gcc.target/i386/pr85403.c trunk/gcc/testsuite/gcc.target/i386/ret-thunk-26.c
