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# This testcase is part of GDB, the GNU debugger.

# Copyright 2004, 2005, 2007, 2008, 2009, 2010 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 .

# Check that GDB can and only executes single instructions when

# stepping through a sequence of breakpoints interleaved by a signal

# handler.

# This test is known to tickle the following problems: kernel letting

# the inferior execute both the system call, and the instruction

# following, when single-stepping a system call; kernel failing to

# propogate the single-step state when single-stepping the sigreturn

# system call, instead resuming the inferior at full speed; GDB

# doesn't know how to software single-step across a sigreturn

# instruction.  Since the kernel problems can be "fixed" using

# software single-step this is KFAILed rather than XFAILed.

if [target_info exists gdb,nosignals] {

    verbose "Skipping sigbpt.exp because of nosignals."

    continue

}

if $tracelevel {

    strace $tracelevel

}

set prms_id 0

set bug_id 0

set testfile "sigbpt"

set srcfile ${testfile}.c

set binfile ${objdir}/${subdir}/${testfile}

if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {

    untested sigbpt.exp

    return -1

}

gdb_exit

gdb_start

gdb_reinitialize_dir $srcdir/$subdir

gdb_load ${binfile}

#

# Run to `main' where we begin our tests.

#

if ![runto_main] then {

    gdb_suppress_tests

}

# If we can examine what's at memory address 0, it is possible that we

# could also execute it.  This could probably make us run away,

# executing random code, which could have all sorts of ill effects,

# especially on targets without an MMU.  Don't run the tests in that

# case.

send_gdb "x 0\n"

gdb_expect {

    -re "0x0:.*Cannot access memory at address 0x0.*$gdb_prompt $" { }

    -re "0x0:.*Error accessing memory address 0x0.*$gdb_prompt $" { }

    -re ".*$gdb_prompt $" {

        untested "Memory at address 0 is possibly executable"

        return

    }

}

gdb_test "break keeper"

# Run to bowler, and then single step until there's a SIGSEGV.  Record

# the address of each single-step instruction (up to and including the

# instruction that causes the SIGSEGV) in bowler_addrs, and the address

# of the actual SIGSEGV in segv_addr.

# Note: this test detects which signal is received.  Usually it is SIGSEGV

# (and we use SIGSEGV in comments) but on Darwin it is SIGBUS.

set bowler_addrs bowler

set segv_addr none

gdb_test {display/i $pc}

gdb_test "advance *bowler" "bowler.*" "advance to the bowler"

set test "stepping to fault"

set signame "SIGSEGV"

gdb_test_multiple "stepi" "$test" {

    -re "Program received signal (SIGBUS|SIGSEGV).*pc(\r\n| *) *=> (0x\[0-9a-f\]*).*$gdb_prompt $" {

        set signame $expect_out(1,string)

        set segv_addr $expect_out(3,string)

        pass "$test"

    }

    -re " .*pc(\r\n| *)=> (0x\[0-9a-f\]*).*bowler.*$gdb_prompt $" {

        set bowler_addrs [concat $expect_out(2,string) $bowler_addrs]

        send_gdb "stepi\n"

        exp_continue

    }

}

# Now record the address of the instruction following the faulting

# instruction in bowler_addrs.

set test "get insn after fault"

gdb_test_multiple {x/2i $pc} "$test" {

    -re "=> (0x\[0-9a-f\]*).*bowler.*(0x\[0-9a-f\]*).*bowler.*$gdb_prompt $" {

        set bowler_addrs [concat $expect_out(2,string) $bowler_addrs]

        pass "$test"

    }

}

# Procedures for returning the address of the instruction before, at

# and after, the faulting instruction.

proc before_segv { } {

    global bowler_addrs

    return [lindex $bowler_addrs 2]

}

proc at_segv { } {

    global bowler_addrs

    return [lindex $bowler_addrs 1]

}

proc after_segv { } {

    global bowler_addrs

    return [lindex $bowler_addrs 0]

}

# Check that the address table and SIGSEGV correspond.

set test "Verify that ${signame} occurs at the last STEPI insn"

if {[string compare $segv_addr [at_segv]] == 0} {

    pass "$test"

} else {

    fail "$test ($segv_addr [at_segv])"

}

# Check that the inferior is correctly single stepped all the way back

# to a faulting instruction.

proc stepi_out { name args } {

    global gdb_prompt

    global signame

    # Set SIGSEGV to pass+nostop and then run the inferior all the way

    # through to the signal handler.  With the handler is reached,

    # disable SIGSEGV, ensuring that further signals stop the

    # inferior.  Stops a SIGSEGV infinite loop when a broke system

    # keeps re-executing the faulting instruction.

    rerun_to_main

    gdb_test "handle ${signame} nostop print pass" "" "${name}; pass ${signame}"

    gdb_test "continue" "keeper.*" "${name}; continue to keeper"

    gdb_test "handle ${signame} stop print nopass" "" "${name}; nopass ${signame}"

    # Insert all the breakpoints.  To avoid the need to step over

    # these instructions, this is delayed until after the keeper has

    # been reached.

    for {set i 0} {$i < [llength $args]} {incr i} {

        gdb_test "break [lindex $args $i]" "Breakpoint.*" \

            "${name}; set breakpoint $i of [llength $args]"

    }

    # Single step our way out of the keeper, through the signal

    # trampoline, and back to the instruction that faulted.

    set test "${name}; stepi out of handler"

    gdb_test_multiple "stepi" "$test" {

        -re "Could not insert single-step breakpoint.*$gdb_prompt $" {

            setup_kfail "sparc*-*-openbsd*" gdb/1736

            fail "$test (could not insert single-step breakpoint)"

        }

        -re "keeper.*$gdb_prompt $" {

            send_gdb "stepi\n"

            exp_continue

        }

        -re "signal handler.*$gdb_prompt $" {

            send_gdb "stepi\n"

            exp_continue

        }

        -re "Program received signal SIGSEGV.*$gdb_prompt $" {

            kfail gdb/1702 "$test (executed fault insn)"

        }

        -re "Breakpoint.*pc(\r\n| *)[at_segv] .*bowler.*$gdb_prompt $" {

            pass "$test (at breakpoint)"

        }

        -re "Breakpoint.*pc(\r\n| *)[after_segv] .*bowler.*$gdb_prompt $" {

            kfail gdb/1702 "$test (executed breakpoint)"

        }

        -re "pc(\r\n| *)[at_segv] .*bowler.*$gdb_prompt $" {

            pass "$test"

        }

        -re "pc(\r\n| *)[after_segv] .*bowler.*$gdb_prompt $" {

            kfail gdb/1702 "$test (skipped fault insn)"

        }

        -re "pc(\r\n| *)=> 0x\[a-z0-9\]* .*bowler.*$gdb_prompt $" {

            kfail gdb/1702 "$test (corrupt pc)"

        }

    }

    # Clear any breakpoints

    for {set i 0} {$i < [llength $args]} {incr i} {

        gdb_test "clear [lindex $args $i]" "Deleted .*" \

            "${name}; clear breakpoint $i of [llength $args]"

    }

}

# Let a signal handler exit, returning to a breakpoint instruction

# inserted at the original fault instruction.  Check that the

# breakpoint is hit, and that single stepping off that breakpoint

# executes the underlying fault instruction causing a SIGSEGV.

proc cont_out { name args } {

    global gdb_prompt

    global signame

    # Set SIGSEGV to pass+nostop and then run the inferior all the way

    # through to the signal handler.  With the handler is reached,

    # disable SIGSEGV, ensuring that further signals stop the

    # inferior.  Stops a SIGSEGV infinite loop when a broke system

    # keeps re-executing the faulting instruction.

    rerun_to_main

    gdb_test "handle ${signame} nostop print pass" "" "${name}; pass ${signame}"

    gdb_test "continue" "keeper.*" "${name}; continue to keeper"

    gdb_test "handle ${signame} stop print nopass" "" "${name}; nopass ${signame}"

    # Insert all the breakpoints.  To avoid the need to step over

    # these instructions, this is delayed until after the keeper has

    # been reached.  Always set a breakpoint at the signal trampoline

    # instruction.

    set args [concat $args "*[at_segv]"]

    for {set i 0} {$i < [llength $args]} {incr i} {

        gdb_test "break [lindex $args $i]" "Breakpoint.*" \

            "${name}; set breakpoint $i  of [llength $args]"

    }

    # Let the handler return, it should "appear to hit" the breakpoint

    # inserted at the faulting instruction.  Note that the breakpoint

    # instruction wasn't executed, rather the inferior was SIGTRAPed

    # with the PC at the breakpoint.

    gdb_test "continue" "Breakpoint.*pc(\r\n| *)=> [at_segv] .*" \

        "${name}; continue to breakpoint at fault"

    # Now single step the faulted instrction at that breakpoint.

    gdb_test "stepi" \

        "Program received signal ${signame}.*pc(\r\n| *)=> [at_segv] .*" \

        "${name}; stepi fault"

    # Clear any breakpoints

    for {set i 0} {$i < [llength $args]} {incr i} {

        gdb_test "clear [lindex $args $i]" "Deleted .*" \

            "${name}; clear breakpoint $i of [llength $args]"

    }

}

# Try to confuse DECR_PC_AFTER_BREAK architectures by scattering

# breakpoints around the faulting address.  In all cases the inferior

# should single-step out of the signal trampoline halting (but not

# executing) the fault instruction.

stepi_out "stepi"

stepi_out "stepi bp before segv" "*[before_segv]"

stepi_out "stepi bp at segv" "*[at_segv]"

stepi_out "stepi bp before and at segv" "*[at_segv]" "*[before_segv]"

# Try to confuse DECR_PC_AFTER_BREAK architectures by scattering

# breakpoints around the faulting address.  In all cases the inferior

# should exit the signal trampoline halting at the breakpoint that

# replaced the fault instruction.

cont_out "cont"

cont_out "cont bp after segv" "*[before_segv]"

cont_out "cont bp before and after segv" "*[before_segv]" "*[after_segv]"