From c4c22e830251e1961c6ebec78d28d039eb2e6017 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Thu, 16 Jul 2020 07:03:27 -0700 Subject: [PATCH] LTO: Add -fcf-protection=check Mixing -fcf-protection and -fcf-protection=none objects are allowed. Linker just merges -fcf-protection values from all input objects. Add -fcf-protection=check for the final link with LTO. An error is issued if LTO object files are compiled with different -fcf-protection values. Otherwise, -fcf-protection=check is ignored at the compile time. Without explicit -fcf-protection at link time, -fcf-protection values from LTO object files are merged at the final link. gcc/ PR bootstrap/96203 * common.opt: Add -fcf-protection=check. * flag-types.h (cf_protection_level): Add CF_CHECK. * lto-wrapper.c (merge_and_complain): Issue an error for mismatching -fcf-protection values with -fcf-protection=check. Otherwise, merge -fcf-protection values. * doc/invoke.texi: Document -fcf-protection=check. gcc/testsuite/ PR bootstrap/96203 * gcc.target/i386/pr96203-1.c: New test. * gcc.target/i386/pr96203-2.c: Likewise. --- gcc/common.opt | 5 +++- gcc/doc/invoke.texi | 9 +++++-- gcc/flag-types.h | 3 ++- gcc/lto-wrapper.c | 39 +++++++++++++++++++++++++------ gcc/testsuite/gcc.target/i386/pr96203-1.c | 18 ++++++++++++++ gcc/testsuite/gcc.target/i386/pr96203-2.c | 11 +++++++++ 6 files changed, 74 insertions(+), 11 deletions(-) create mode 100644 gcc/testsuite/gcc.target/i386/pr96203-1.c create mode 100644 gcc/testsuite/gcc.target/i386/pr96203-2.c diff --git a/gcc/common.opt b/gcc/common.opt index a3893a4..47f4261 100644 --- a/gcc/common.opt +++ b/gcc/common.opt @@ -1776,7 +1776,7 @@ Common RejectNegative Alias(fcf-protection=,full) fcf-protection= Common Report Joined RejectNegative Enum(cf_protection_level) Var(flag_cf_protection) Init(CF_NONE) --fcf-protection=[full|branch|return|none] Instrument functions with checks to verify jump/call/return control-flow transfer +-fcf-protection=[full|branch|return|none|check] Instrument functions with checks to verify jump/call/return control-flow transfer instructions have valid targets. Enum @@ -1792,6 +1792,9 @@ EnumValue Enum(cf_protection_level) String(return) Value(CF_RETURN) EnumValue +Enum(cf_protection_level) String(check) Value(CF_CHECK) + +EnumValue Enum(cf_protection_level) String(none) Value(CF_NONE) finstrument-functions diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 5449c33..7c3cc14 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -559,7 +559,7 @@ Objective-C and Objective-C++ Dialects}. -fsanitize=@var{style} -fsanitize-recover -fsanitize-recover=@var{style} @gol -fasan-shadow-offset=@var{number} -fsanitize-sections=@var{s1},@var{s2},... @gol -fsanitize-undefined-trap-on-error -fbounds-check @gol --fcf-protection=@r{[}full@r{|}branch@r{|}return@r{|}none@r{]} @gol +-fcf-protection=@r{[}full@r{|}branch@r{|}return@r{|}none@r{|}check@r{]} @gol -fstack-protector -fstack-protector-all -fstack-protector-strong @gol -fstack-protector-explicit -fstack-check @gol -fstack-limit-register=@var{reg} -fstack-limit-symbol=@var{sym} @gol @@ -14211,7 +14211,7 @@ operand constant, @code{__sanitizer_cov_trace_cmpf} or @code{__sanitizer_cov_trace_cmpd} for float or double comparisons and @code{__sanitizer_cov_trace_switch} for switch statements. -@item -fcf-protection=@r{[}full@r{|}branch@r{|}return@r{|}none@r{]} +@item -fcf-protection=@r{[}full@r{|}branch@r{|}return@r{|}none@r{|}check@r{]} @opindex fcf-protection Enable code instrumentation of control-flow transfers to increase program security by checking that target addresses of control-flow @@ -14229,6 +14229,11 @@ function. The value @code{full} is an alias for specifying both @code{branch} and @code{return}. The value @code{none} turns off instrumentation. +The value @code{check} is used for the final link with link-time +optimization (LTO). An error is issued if LTO object files are +compiled with different @option{-fcf-protection} values. The +value @code{check} is ignored at the compile time. + 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 diff --git a/gcc/flag-types.h b/gcc/flag-types.h index b092c56..852ea76 100644 --- a/gcc/flag-types.h +++ b/gcc/flag-types.h @@ -368,7 +368,8 @@ enum cf_protection_level CF_BRANCH = 1 << 0, CF_RETURN = 1 << 1, CF_FULL = CF_BRANCH | CF_RETURN, - CF_SET = 1 << 2 + CF_SET = 1 << 2, + CF_CHECK = 1 << 3 }; /* Parloops schedule type. */ diff --git a/gcc/lto-wrapper.c b/gcc/lto-wrapper.c index 5578b6d..e3b5cb2 100644 --- a/gcc/lto-wrapper.c +++ b/gcc/lto-wrapper.c @@ -310,20 +310,45 @@ merge_and_complain (struct cl_decoded_option **decoded_options, case OPT_fcf_protection_: /* Default to link-time option, else append or check identical. */ - if (!cf_protection_option) + if (!cf_protection_option + || cf_protection_option->value == CF_CHECK) { for (j = 0; j < *decoded_options_count; ++j) if ((*decoded_options)[j].opt_index == foption->opt_index) break; if (j == *decoded_options_count) append_option (decoded_options, decoded_options_count, foption); - else if (strcmp ((*decoded_options)[j].arg, foption->arg)) - fatal_error (input_location, - "option -fcf-protection with mismatching values" - " (%s, %s)", - (*decoded_options)[j].arg, foption->arg); + else if ((*decoded_options)[j].value != foption->value) + { + if (cf_protection_option + && cf_protection_option->value == CF_CHECK) + fatal_error (input_location, + "option -fcf-protection with mismatching values" + " (%s, %s)", + (*decoded_options)[j].arg, foption->arg); + else + { + /* Merge and update the -fcf-protection option. */ + (*decoded_options)[j].value &= (foption->value + & CF_FULL); + switch ((*decoded_options)[j].value) + { + case CF_NONE: + (*decoded_options)[j].arg = "none"; + break; + case CF_BRANCH: + (*decoded_options)[j].arg = "branch"; + break; + case CF_RETURN: + (*decoded_options)[j].arg = "return"; + break; + default: + gcc_unreachable (); + } + } + } } - break; + break; case OPT_O: case OPT_Ofast: diff --git a/gcc/testsuite/gcc.target/i386/pr96203-1.c b/gcc/testsuite/gcc.target/i386/pr96203-1.c new file mode 100644 index 0000000..332911f --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr96203-1.c @@ -0,0 +1,18 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fcf-protection=check" } */ +/* { dg-final { scan-assembler-not "endbr" } } */ + +extern int x; + +static void +__attribute__ ((noinline, noclone)) +test (int i) +{ + x = i; +} + +void +bar (int i) +{ + test (i); +} diff --git a/gcc/testsuite/gcc.target/i386/pr96203-2.c b/gcc/testsuite/gcc.target/i386/pr96203-2.c new file mode 100644 index 0000000..1141cf2 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr96203-2.c @@ -0,0 +1,11 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fcf-protection=check -mmanual-endbr" } */ +/* { dg-final { scan-assembler-not "endbr" } } */ + +extern void bar (void) __attribute__((__cf_check__)); + +void +foo (void) +{ + bar (); +} -- 2.7.4