gdb/testsuite/gdb.arch/i386-prologue-skip-cf-protection.exp

# Copyright 2020-2025 Free Software Foundation, Inc.

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# Test skipping a prologue that was generated with gcc's -fcf-protection=full
# (control flow protection) option.
#
# This option places an `endbr32`/`endbr64` instruction at the start of
# all functions, which can interfere with prologue analysis.

standard_testfile .c -stackalign.c

require {is_any_target x86_64-*-* i?86-*-*}
require supports_fcf_protection

# Tests if breakpoint set on main is placed past main's entry.
proc test_run {} {
    # Get start address of function main.
    set main_addr [get_integer_valueof &main -1]
    gdb_assert {$main_addr != -1}

    set bp_addr -1

    # Put breakpoint on main, get the address where the breakpoint was installed.
    gdb_test_multiple "break -q main" "break on main, get address" {
	-re -wrap "Breakpoint $::decimal at ($::hex).*" {
	    set bp_addr $expect_out(1,string)

	    # Convert to decimal.
	    set bp_addr [expr $bp_addr]

	    pass $gdb_test_name
	}
    }

    # Make sure some prologue was skipped.
    gdb_assert {$bp_addr != -1 && $bp_addr > $main_addr} \
	"breakpoint placed past main's entry"
}

with_test_prefix "skip-cf-protection" {
    set opts {debug additional_flags=-fcf-protection=full}

    if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable \
	$opts] != "" } {
	untested "failed to compile"
	return
    }

    clean_restart ${::testfile}

    test_run
}

# Now, make sure that the prologue analysis does not end up at function's entry
# when stack alignment sequence is generated right after 'endbr64'/'endbr32'.
# That could happen if GDB handled those incorrectly - there was a bug that
# checked for those two in incorrect order, which caused such issue.
with_test_prefix "skip-cf-protection-stackalign" {
    # gcc is easier to make it produce the sequence of interest.
    if { ![is_c_compiler_gcc] } {
	unsupported "stackalign test part requires gcc compiler"
	return
    }

    if { [prepare_for_testing "failed to prepare" "${testfile}-stackalign" \
	$srcfile2 [list optimize=-O0 additional_flags=-fcf-protection=full]] } {
	return
    }

    test_run
}