gdb/testsuite/gdb.base/range-stepping.exp

# Copyright 2013-2020 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/>.

load_lib "range-stepping-support.exp"

standard_testfile
set executable $testfile

if { [prepare_for_testing "failed to prepare" $testfile $srcfile {debug}] } {
    return -1
}

if ![runto_main] {
    fail "can't run to main"
    return -1
}

if ![gdb_range_stepping_enabled] {
    unsupported "range stepping not supported by the target"
    return -1
}

# Check that range stepping can step a range of multiple instructions.

with_test_prefix "multi insns" {

    gdb_breakpoint [gdb_get_line_number "location 1"]
    gdb_continue_to_breakpoint "location 1"

    set pc_before_stepping ""
    set test "pc before stepping"
    gdb_test_multiple "print/x \$pc" $test {
	-re "\\\$$decimal = (\[^\r\n\]*)\r\n$gdb_prompt $" {
	    set pc_before_stepping $expect_out(1,string)
	    pass $test
	}
    }

    # When "next" is executed, GDB should send one vCont;s and vCont;r
    # and receive two stop replies:
    #
    # --> vCont;s  (step over breakpoint)
    # <-- T05
    # --> vCont;rSTART,END  (range step)
    # <-- T05
    set result [exec_cmd_expect_vCont_count "next" 1]
    if { $result } {
	# This is the first range-stepping test, and the simplest
	# one.  If it fails, probably the rest of the tests would
	# fail too, and the huge number of rsp packets in the test
	# with the time-consuming loop would blow up the gdb.log file.
	# Skip the rest of the tests.
	return
    }

    set pc_after_stepping ""
    set msg "pc after stepping"
    gdb_test_multiple "print/x \$pc" $msg {
	-re "\\\$$decimal = (\[^\r\n\]*)\r\n$gdb_prompt $" {
	    set pc_after_stepping $expect_out(1,string)
	    pass $msg
	}
    }

    # There should be at least two instructions between
    # PC_BEFORE_STEPPING and PC_AFTER_STEPPING.
    gdb_test "disassemble ${pc_before_stepping},${pc_after_stepping}" \
	"${hex} <main\\+${decimal}>:.*${hex} <main\\+${decimal}>:.*" \
	"stepped multiple insns"
}

# Check that range stepping can step over a function.

with_test_prefix "step over func" {

    set line_num [gdb_get_line_number "location 2"]
    gdb_test "where" "main \\(\\) at .*${srcfile}:${line_num}.*"

    # It's expected to get three stops and two 'vCont;r's.  In the C
    # code, the line of C source produces roughly the following
    # instructions:
    #
    # addr1:
    #  insn1
    #  insn2
    #  ...
    #  call func1
    # addr2:
    #  ...
    #  insn3
    # addr3:
    #  insn4
    #
    # Something like this will happen:
    # --> vCont;rADDR1,ADDR3  (range step from ADDR1 to ADDR3)
    # <-- T05  (target single-stepped to func, which is out of the step range)
    # --> $Z0,ADDR2  (place step-resume breakpoint at ADDR2)
    # --> vCont;c  (resume)
    # <-- T05  (target stops at ADDR2)
    # --> vCont;rADDR1,ADDR3  (continues range stepping)
    # <-- T05
    exec_cmd_expect_vCont_count "next" 2
}

# Check that breakpoints interrupt range stepping correctly.

with_test_prefix "breakpoint" {
    gdb_breakpoint "func1"
    # Something like this will happen:
    # --> vCont;rADDR1,ADDR3
    # <-- T05  (target single-steps to func1, which is out of the step range)
    # --> $Z0,ADDR2  (step-resume breakpoint at ADDR2)
    # --> vCont;c  (resume)
    # <-- T05  (target hits the breakpoint at func1)
    exec_cmd_expect_vCont_count "next" 1

    gdb_test "backtrace" "#0 .* func1 .*#1 .* main .*" \
	"backtrace from func1"

    # A cancelled range step should not confuse the following
    # execution commands.
    exec_cmd_expect_vCont_count "stepi" 0
    gdb_test "finish" ".*"
    gdb_test "next" ".*"
    delete_breakpoints
}

# Check that range stepping works well even when there's a loop in the
# step range.

with_test_prefix "loop" {

    # GDB should send one vCont;r and receive one stop reply:
    # --> vCont;rSTART,END  (range step)
    # <-- T05
    exec_cmd_expect_vCont_count "next" 1

    # Confirm the loop completed.
    gdb_test "print a" " = 15"
    gdb_test "print e" " = 105"
}

# Check that range stepping works well even when the target's PC was
# already within the loop's body.

with_test_prefix "loop 2" {
    # Stepi into the loop body.  15 should be large enough to make
    # sure the program stops within the loop's body.
    gdb_test "stepi 15" ".*"
    # GDB should send one vCont;r and receive one stop reply:
    # --> vCont;rSTART,END  (range step)
    # <-- T05
    exec_cmd_expect_vCont_count "next" 1

    # Confirm the loop completed.
    gdb_test "print a" " = 15"
    gdb_test "print e" " = 105"
}

# Check that range stepping works well even when it is interrupted by
# ctrl-c.

if ![target_info exists gdb,nointerrupts] {
    with_test_prefix "interrupt" {
	gdb_test_no_output "set debug remote 1"

	send_gdb "next\n"
	sleep 1
	send_gdb "\003"

	# GDB should send one vCont;r and receive one stop reply for
	# SIGINT:
	# --> vCont;rSTART,END  (range step)
	# <-- T02  (SIGINT)

	set vcont_r_counter 0

	set test "send ctrl-c to GDB"
	gdb_test_multiple "" $test {
	    -re "vCont;r\[^\r\n\]*\.\.\." {
		incr vcont_r_counter
		exp_continue
	    }
	    -re "Program received signal SIGINT.*$gdb_prompt $" {
		pass $test
	    }
	}
	gdb_test_no_output "set debug remote 0"

	# Check the number of 'vCont;r' packets.
	if { $vcont_r_counter == 1 } {
	    pass "${test}: 1 vCont;r"
	} else {
	    fail "${test}: 1 vCont;r"
	}

	# Break the loop earlier and continue range stepping.
	gdb_test "set variable c = 0"
	exec_cmd_expect_vCont_count "next" 1
    }
}

# Check that range stepping doesn't break software watchpoints.  With
# those, GDB needs to be notified of all single-steps, to evaluate
# whether the watched value changes at each step.
with_test_prefix "software watchpoint" {
    gdb_test "step" "soft-watch.*" "step into multiple instruction line"
    # A software watchpoint at PC makes the thread stop before the
    # whole line range is over (after one single-step, actually).
    gdb_test "watch \$pc" ".*" "set watchpoint"
    gdb_test "step" "soft-watch.*" "step still in same line"
}

return 0