From 9be3bb2c0a258fd6a7d3d05d232a21930c757d3c Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Wed, 29 Apr 2020 04:52:46 -0700 Subject: [PATCH] x86: Allow -fcf-protection with external thunk Allow -fcf-protection with external thunk since the external thunk can be made compatible with -fcf-protection. gcc/ PR target/93654 * config/i386/i386-options.c (ix86_set_indirect_branch_type): Allow -fcf-protection with -mindirect-branch=thunk-extern and -mfunction-return=thunk-extern. * doc/invoke.texi: Update notes for -fcf-protection=branch with -mindirect-branch=thunk-extern and -mindirect-return=thunk-extern. gcc/testsuite/ PR target/93654 * gcc.target/i386/pr93654.c: New test. --- gcc/ChangeLog | 9 +++++++++ gcc/config/i386/i386-options.c | 4 ++++ gcc/doc/invoke.texi | 10 +++++++--- gcc/testsuite/ChangeLog | 5 +++++ gcc/testsuite/gcc.target/i386/pr93654.c | 9 +++++++++ 5 files changed, 34 insertions(+), 3 deletions(-) create mode 100644 gcc/testsuite/gcc.target/i386/pr93654.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 2287ff9..6741793 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,12 @@ +2020-04-29 H.J. Lu + + PR target/93654 + * config/i386/i386-options.c (ix86_set_indirect_branch_type): + Allow -fcf-protection with -mindirect-branch=thunk-extern and + -mfunction-return=thunk-extern. + * doc/invoke.texi: Update notes for -fcf-protection=branch with + -mindirect-branch=thunk-extern and -mindirect-return=thunk-extern. + 2020-04-29 Richard Sandiford * doc/sourcebuild.texi: Add missing arm_arch_v8a_hard_ok anchor. diff --git a/gcc/config/i386/i386-options.c b/gcc/config/i386/i386-options.c index e0be493..5c21fce 100644 --- a/gcc/config/i386/i386-options.c +++ b/gcc/config/i386/i386-options.c @@ -3083,6 +3083,8 @@ ix86_set_indirect_branch_type (tree fndecl) ? "thunk-extern" : "thunk")); if (cfun->machine->indirect_branch_type != indirect_branch_keep + && (cfun->machine->indirect_branch_type + != indirect_branch_thunk_extern) && (flag_cf_protection & CF_RETURN)) error ("%<-mindirect-branch%> and %<-fcf-protection%> are not " "compatible"); @@ -3126,6 +3128,8 @@ ix86_set_indirect_branch_type (tree fndecl) ? "thunk-extern" : "thunk")); if (cfun->machine->function_return_type != indirect_branch_keep + && (cfun->machine->function_return_type + != indirect_branch_thunk_extern) && (flag_cf_protection & CF_RETURN)) error ("%<-mfunction-return%> and %<-fcf-protection%> are not " "compatible"); diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index fed38e8..5bb7d94 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -30097,9 +30097,9 @@ Note that @option{-mcmodel=large} is incompatible with @option{-mindirect-branch=thunk-extern} since the thunk function may not be reachable in the large code model. -Note that @option{-mindirect-branch=thunk-extern} is incompatible with -@option{-fcf-protection=branch} since the external thunk cannot be modified -to disable control-flow check. +Note that @option{-mindirect-branch=thunk-extern} is compatible with +@option{-fcf-protection=branch} since the external thunk can be made +to enable control-flow check. @item -mfunction-return=@var{choice} @opindex mfunction-return @@ -30112,6 +30112,10 @@ object file. You can control this behavior for a specific function by using the function attribute @code{function_return}. @xref{Function Attributes}. +Note that @option{-mindirect-return=thunk-extern} is compatible with +@option{-fcf-protection=branch} since the external thunk can be made +to enable control-flow check. + Note that @option{-mcmodel=large} is incompatible with @option{-mfunction-return=thunk} and @option{-mfunction-return=thunk-extern} since the thunk function may diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index b4d1ee2..b635ce1 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2020-04-29 H.J. Lu + + PR target/93654 + * gcc.target/i386/pr93654.c: New test. + 2020-04-29 Richard Sandiford * lib/target-supports.exp: Add v8a_hard to the list of arm_arch_* diff --git a/gcc/testsuite/gcc.target/i386/pr93654.c b/gcc/testsuite/gcc.target/i386/pr93654.c new file mode 100644 index 0000000..ec5bdce --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr93654.c @@ -0,0 +1,9 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fcf-protection -mfunction-return=thunk-extern -mindirect-branch=thunk-extern" } */ + +int +bar (void (*foo) (void)) +{ + foo (); + return 0; +} -- 2.7.4