Define __CET__ for -fcf-protection and remove -mibt

With revision 259496:

commit b1384095a7c1d06a44b70853372ebe037b2f7867
Author: hjl <hjl@138bc75d-0d04-0410-961f-82ee72b054a4>
Date:   Thu Apr 19 15:15:04 2018 +0000

    x86: Enable -fcf-protection with multi-byte NOPs

-mibt does nothing and can be removed.  Define __CET__ to indicate level
protection with -fcf-protection:

(__CET__ & 1) != 0: -fcf-protection=branch or -fcf-protection=full
(__CET__ & 2) != 0: -fcf-protection=return or -fcf-protection=full

gcc/

	PR target/85469
	* common/config/i386/i386-common.c (OPTION_MASK_ISA_IBT_SET):
	Removed.
	(OPTION_MASK_ISA_IBT_UNSET): Likewise.
	(ix86_handle_option): Don't handle OPT_mibt.
	* config/i386/cet.h: Check __CET__ instead of __IBT__ and
	__SHSTK__.
	* config/i386/driver-i386.c (host_detect_local_cpu): Remove
	has_ibt and ibt.
	* config/i386/i386-c.c (ix86_target_macros_internal): Don't
	check OPTION_MASK_ISA_IBT nor flag_cf_protection.
	(ix86_target_macros): Define __CET__ with flag_cf_protection
	for -fcf-protection.
	* config/i386/i386.c (isa2_opts): Remove -mibt.
	* config/i386/i386.h (TARGET_IBT): Removed.
	(TARGET_IBT_P): Likewise.
	(ix86_valid_target_attribute_inner_p): Don't check OPT_mibt.
	* config/i386/i386.md (nop_endbr): Don't check TARGET_IBT.
	* config/i386/i386.opt (mcet): Update help message.
	(mshstk): Likewise.
	(mibt): Removed.
	* doc/invoke.texi: Remove -mibt.  Document __CET__.  Document
	-mcet as an alias for -mshstk.

gcc/testsuite/

	PR target/85469
	* gcc.target/i386/pr85044.c (dg-options): Remove -mibt.
	* gcc.target/i386/sse-26.c (dg-options): Remove -mno-ibt.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@259522 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 11 insertions, 17 deletions

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 0f2c83964f49..b6784b75fa22 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -1261,7 +1261,7 @@ See RS/6000 and PowerPC Options.
 -msse4a  -m3dnow  -m3dnowa  -mpopcnt  -mabm  -mbmi  -mtbm  -mfma4  -mxop @gol
 -mlzcnt  -mbmi2  -mfxsr  -mxsave  -mxsaveopt  -mrtm  -mlwp  -mmpx  @gol
 -mmwaitx  -mclzero  -mpku  -mthreads -mgfni  -mvaes  @gol
--mcet -mibt -mshstk -mforce-indirect-call -mavx512vbmi2 @gol
+-mcet -mshstk -mforce-indirect-call -mavx512vbmi2 @gol
 -mvpclmulqdq -mavx512bitalg -mmovdiri -mmovdir64b -mavx512vpopcntdq @gol
 -mms-bitfields  -mno-align-stringops  -minline-all-stringops @gol
 -minline-stringops-dynamically  -mstringop-strategy=@var{alg} @gol
@@ -11829,6 +11829,11 @@ function.  The value @code{full} is an alias for specifying both
 @code{branch} and @code{return}. The value @code{none} turns off
 instrumentation.
 
+The macro @code{__CET__} is defined when @option{-fcf-protection} is
+used.  The first bit of @code{__CET__} is set to 1 for the value
+@code{branch} and the second bit of @code{__CET__} is set to 1 for
+the @code{return}.
+
 You can also use the @code{nocf_check} attribute to identify
 which functions and calls should be skipped from instrumentation
 (@pxref{Function Attributes}).
@@ -27349,11 +27354,6 @@ supported architecture, using the appropriate flags.  In particular,
 the file containing the CPU detection code should be compiled without
 these options.
 
-The @option{-mcet} option turns on the @option{-mibt} and @option{-mshstk}
-options.  The compiler provides a number of built-in functions for
-fine-grained control in a CET-based application.  See
-@xref{x86 Built-in Functions}, for more information.
-
 @item -mdump-tune-features
 @opindex mdump-tune-features
 This option instructs GCC to dump the names of the x86 performance 
@@ -27446,19 +27446,13 @@ see @ref{Other Builtins} for details.
 This option enables use of the @code{movbe} instruction to implement
 @code{__builtin_bswap32} and @code{__builtin_bswap64}.
 
-@item -mibt
-@opindex mibt
-This option enables indirect branch tracking built-in functions from
-x86 Control-flow Enforcement Technology (CET).  The option
-@option{-mibt} is on by default when the @code{-mcet} option is
-specified.
-
 @item -mshstk
+@itemx -mcet
 @opindex mshstk
-This option enables shadow stack built-in functions from x86
-Control-flow Enforcement Technology (CET).  The option
-@option{-mshstk} is on by default when the @option{-mcet} option is
-specified.
+@opindex mcet
+The @option{-mshstk} option enables shadow stack built-in functions
+from x86 Control-flow Enforcement Technology (CET).  The @option{-mcet}
+option is an alias for the @option{-mshstk} option.
 
 @item -mcrc32
 @opindex mcrc32