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| author | H.J. Lu <hongjiu.lu@intel.com> | 2018-12-14 21:35:36 +0000 |
|---|---|---|
| committer | H.J. Lu <hjl@gcc.gnu.org> | 2018-12-14 13:35:36 -0800 |
| commit | 06553c89f521477d6c3ec4023d5162f90c57111d (patch) | |
| tree | c6d500a4d04a1fcee026fc1b5125e4a7a2b05a31 /gcc/doc | |
| parent | c759830b29fff2288bc0cebfb4b2c479f0b5b30e (diff) | |
| download | gcc-06553c89f521477d6c3ec4023d5162f90c57111d.zip gcc-06553c89f521477d6c3ec4023d5162f90c57111d.tar.gz gcc-06553c89f521477d6c3ec4023d5162f90c57111d.tar.bz2 | |
x86; Add -mmanual-endbr and cf_check function attribute
Currently GCC inserts ENDBR instruction at entries of all non-static
functions, unless LTO compilation is used. Marking all functions,
which are not called indirectly with nocf_check attribute, is not
ideal since 99% of functions in a program may be of this kind.
This patch adds -mmanual-endbr and cf_check function attribute. They
can be used together with -fcf-protection such that ENDBR instruction
is inserted only at entries of functions with cf_check attribute. It
can limit number of ENDBR instructions to reduce program size.
gcc/
* config/i386/i386.c (rest_of_insert_endbranch): Insert ENDBR
at the function entry only when -mmanual-endbr isn't used or
there is cf_check function attribute.
(ix86_attribute_table): Add cf_check.
* config/i386/i386.opt: Add -mmanual-endbr.
* doc/extend.texi: Document cf_check attribute.
* doc/invoke.texi: Document -mmanual-endbr.
gcc/testsuite/
* gcc.target/i386/cf_check-1.c: New test.
* gcc.target/i386/cf_check-2.c: Likewise.
* gcc.target/i386/cf_check-3.c: Likewise.
* gcc.target/i386/cf_check-4.c: Likewise.
* gcc.target/i386/cf_check-5.c: Likewise.
From-SVN: r267154
Diffstat (limited to 'gcc/doc')
| -rw-r--r-- | gcc/doc/extend.texi | 7 | ||||
| -rw-r--r-- | gcc/doc/invoke.texi | 9 |
2 files changed, 15 insertions, 1 deletions
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index 3889ecb..8f3a21c 100644 --- a/gcc/doc/extend.texi +++ b/gcc/doc/extend.texi @@ -6095,6 +6095,13 @@ foo (void) @} @end smallexample +@item cf_check +@cindex @code{cf_check} function attribute, x86 + +The @code{cf_check} attribute on a function is used to inform the +compiler that ENDBR instruction should be placed at the function +entry when @option{-fcf-protection=branch} is enabled. + @item indirect_return @cindex @code{indirect_return} function attribute, x86 diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 44e1069..9a14170 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -1263,7 +1263,7 @@ See RS/6000 and PowerPC Options. -msse4a -m3dnow -m3dnowa -mpopcnt -mabm -mbmi -mtbm -mfma4 -mxop @gol -mlzcnt -mbmi2 -mfxsr -mxsave -mxsaveopt -mrtm -mlwp @gol -mmwaitx -mclzero -mpku -mthreads -mgfni -mvaes -mwaitpkg @gol --mshstk -mforce-indirect-call -mavx512vbmi2 @gol +-mshstk -mmanual-endbr -mforce-indirect-call -mavx512vbmi2 @gol -mvpclmulqdq -mavx512bitalg -mmovdiri -mmovdir64b -mavx512vpopcntdq @gol -mcldemote -mms-bitfields -mno-align-stringops -minline-all-stringops @gol -minline-stringops-dynamically -mstringop-strategy=@var{alg} @gol @@ -27968,6 +27968,13 @@ Force all calls to functions to be indirect. This is useful when using Intel Processor Trace where it generates more precise timing information for function calls. +@item -mmanual-endbr +@opindex mmanual-endbr +Insert ENDBR instruction at function entry only via the @code{cf_check} +function attribute. This is useful when used with the option +@option{-fcf-protection=branch} to control ENDBR insertion at the +function entry. + @item -mcall-ms2sysv-xlogues @opindex mcall-ms2sysv-xlogues @opindex mno-call-ms2sysv-xlogues |