From: H.J. Lu Date: Fri, 14 Dec 2018 21:35:36 +0000 (+0000) Subject: x86; Add -mmanual-endbr and cf_check function attribute X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=06553c89f521477d6c3ec4023d5162f90c57111d;p=gcc.git 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 --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 7fb4958da48..a612dad682f 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,13 @@ +2018-12-14 H.J. Lu + + * 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. + 2018-12-14 Thomas Schwinge Cesar Philippidis diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c index edc8f4f092e..4599ca2a7d5 100644 --- a/gcc/config/i386/i386.c +++ b/gcc/config/i386/i386.c @@ -2640,6 +2640,9 @@ rest_of_insert_endbranch (void) if (!lookup_attribute ("nocf_check", TYPE_ATTRIBUTES (TREE_TYPE (cfun->decl))) + && (!flag_manual_endbr + || lookup_attribute ("cf_check", + DECL_ATTRIBUTES (cfun->decl))) && !cgraph_node::get (cfun->decl)->only_called_directly_p ()) { /* Queue ENDBR insertion to x86_function_profiler. */ @@ -45260,6 +45263,9 @@ static const struct attribute_spec ix86_attribute_table[] = ix86_handle_fentry_name, NULL }, { "fentry_section", 1, 1, true, false, false, false, ix86_handle_fentry_name, NULL }, + { "cf_check", 0, 0, true, false, false, false, + ix86_handle_fndecl_attribute, NULL }, + /* End element. */ { NULL, 0, 0, false, false, false, false, NULL, NULL } }; diff --git a/gcc/config/i386/i386.opt b/gcc/config/i386/i386.opt index b30b55b7826..007e88b57f9 100644 --- a/gcc/config/i386/i386.opt +++ b/gcc/config/i386/i386.opt @@ -1028,6 +1028,11 @@ Target Report Undocumented Var(flag_cet_switch) Init(0) Turn on CET instrumentation for switch statements that use a jump table and an indirect jump. +mmanual-endbr +Target Report Var(flag_manual_endbr) Init(0) +Insert ENDBR instruction at function entry only via cf_check attribute +for CET instrumentation. + mforce-indirect-call Target Report Var(flag_force_indirect_call) Init(0) Make all function calls indirect. diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index 3889ecb5431..8f3a21cfb27 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 44e1069de3b..9a14170d084 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 diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 6b035b34ecf..a0879161104 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,11 @@ +2018-12-14 H.J. Lu + + * 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. + 2018-12-14 Thomas Schwinge Cesar Philippidis diff --git a/gcc/testsuite/gcc.target/i386/cf_check-1.c b/gcc/testsuite/gcc.target/i386/cf_check-1.c new file mode 100644 index 00000000000..c433eab854a --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/cf_check-1.c @@ -0,0 +1,11 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fcf-protection -mmanual-endbr" } */ +/* { dg-final { scan-assembler-not {\mendbr} } } */ + +extern void bar (void) __attribute__((__cf_check__)); + +void +foo (void) +{ + bar (); +} diff --git a/gcc/testsuite/gcc.target/i386/cf_check-2.c b/gcc/testsuite/gcc.target/i386/cf_check-2.c new file mode 100644 index 00000000000..e2b9c4dbcb2 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/cf_check-2.c @@ -0,0 +1,11 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fcf-protection -mno-manual-endbr" } */ +/* { dg-final { scan-assembler-times {\mendbr} 1 } } */ + +extern void bar (void) __attribute__((__cf_check__)); + +void +foo (void) +{ + bar (); +} diff --git a/gcc/testsuite/gcc.target/i386/cf_check-3.c b/gcc/testsuite/gcc.target/i386/cf_check-3.c new file mode 100644 index 00000000000..d835cc3a21b --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/cf_check-3.c @@ -0,0 +1,11 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fcf-protection=none" } */ +/* { dg-final { scan-assembler-not {\mendbr} } } */ + +extern void bar (void) __attribute__((__cf_check__)); + +void +foo (void) +{ + bar (); +} diff --git a/gcc/testsuite/gcc.target/i386/cf_check-4.c b/gcc/testsuite/gcc.target/i386/cf_check-4.c new file mode 100644 index 00000000000..d6cb27cf20b --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/cf_check-4.c @@ -0,0 +1,10 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fcf-protection -mmanual-endbr" } */ +/* { dg-final { scan-assembler-times {\mendbr} 1 } } */ + +extern void foo (void) __attribute__((__cf_check__)); + +void +foo (void) +{ +} diff --git a/gcc/testsuite/gcc.target/i386/cf_check-5.c b/gcc/testsuite/gcc.target/i386/cf_check-5.c new file mode 100644 index 00000000000..f2c0c5c2c09 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/cf_check-5.c @@ -0,0 +1,9 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fcf-protection -mmanual-endbr" } */ +/* { dg-final { scan-assembler-times {\mendbr} 1 } } */ + +__attribute__((__cf_check__)) +void +foo (void) +{ +}