# Copyright 2018-2021 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 essential Machine interface (MI) operations
#
# Verify that -var-update will provide the correct values for floating
# and fixed varobjs that represent the pc register.
#

load_lib mi-support.exp
set MIFLAGS "-i=mi"

standard_testfile basics.c

if {[gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" \
		 executable {debug}] != "" } then {
     untested "failed to compile"
     return -1
}

# Return the address of the specified breakpoint.

proc breakpoint_address {bpnum} {
    global hex
    global expect_out
    global mi_gdb_prompt

    send_gdb "info breakpoint $bpnum\n"
    gdb_expect {
	-re ".*($hex).*$mi_gdb_prompt$" {
	    return $expect_out(1,string)
	}
	-re ".*$mi_gdb_prompt$" {
	    unresolved "get address of breakpoint $bpnum"
	    return ""
	}
	timeout {
	    unresolved "get address of breakpoint $bpnum (timeout)"
	    return ""
	}
    }
}

# Test that a floating varobj representing $pc will provide the
# correct value via -var-update as the program stops at
# breakpoints in different functions.

proc_with_prefix do_floating_varobj_test {} {
    global srcfile binfile
    global hex
    global expect_out

    if {[mi_clean_restart $binfile]} {
	fail "couldn't start gdb"
	return
    }

    mi_runto_main

    # Create a floating varobj for $pc.
    mi_gdb_test "-var-create --thread 1 --frame 0 - @ \$pc" \
	"\\^done,.*value=\"$hex.*" \
	"create varobj for pc in frame 0"

    set nframes 4
    for {set i 1} {$i < $nframes} {incr i} {

	# Run to a breakpoint in each callee function in succession.
	# Note that we can't use mi_runto because we need the
	# breakpoint to be persistent, so we can use its address.
	set bpnum [expr $i + 1]
	mi_create_breakpoint \
	    "basics.c:callee$i" \
	    "insert breakpoint at basics.c:callee$i" \
	    -number $bpnum -func callee$i -file ".*basics.c"

	mi_execute_to "exec-continue" "breakpoint-hit" \
	    "callee$i" ".*" ".*${srcfile}" ".*" \
	    { "" "disp=\"keep\"" } "breakpoint hit in callee$i"

	# Get the value of $pc from the floating varobj.
	mi_gdb_test "-var-update 1 var1" \
	    "\\^done,.*value=\"($hex) .*" \
	    "-var-update for frame $i"
	set pcval $expect_out(3,string)

	# Get the address of the current breakpoint.
	set bpaddr [breakpoint_address $bpnum]
	if {$bpaddr == ""} then { return }

	# Check that the addresses are the same.
	gdb_assert [expr $bpaddr == $pcval] "\$pc equals address of breakpoint in callee$i"
    }
}

# Test that fixed varobjs representing $pc in different stack frames
# will provide the correct value via -var-update after the program
# counter changes (without substantially changing the stack).

proc_with_prefix do_fixed_varobj_test {} {
    global srcfile binfile
    global hex

    if {[mi_clean_restart $binfile] != 0} {
	fail "couldn't start gdb"
	return
    }

    mi_runto_main

    # Run to the function 'callee3' so we have several frames.
    mi_create_breakpoint "basics.c:callee3" \
	"insert breakpoint at basics.c:callee3" \
	-number 2 -func callee3 -file ".*basics.c"

    mi_execute_to "exec-continue" "breakpoint-hit" \
	"callee3" ".*" ".*${srcfile}" ".*" \
	{ "" "disp=\"keep\"" } "breakpoint hit in callee3"

    # At the breakpoint in callee3 there are 4 frames.
    #
    # Create some varobj based on $pc in all frames.  When we single
    # step we expect the varobj for frame 0 to change, while the
    # varobj for all other frames should be unchanged.
    #
    # Track in FIRST_UNCHANGING_VARNUM the number of the first varobj
    # that is not in frame 0, varobj with a lower number we expect to
    # change, while this and later varobj should not change.
    #
    # Track the number of the next varobj to be created in VARNUM.
    set first_unchanging_varnum 0
    set varnum 1

    for {set i 0} {$i < 4} {incr i} {

	if { $i == 1 } then { set first_unchanging_varnum $varnum }

	mi_gdb_test "-var-create --thread 1 --frame $i - \* \$pc" \
	    "\\^done,.*value=\"$hex.*" \
	    "create varobj for \$pc in frame $i"
	incr varnum

	mi_gdb_test "-var-create --thread 1 --frame $i - \* \"global_zero + \$pc\"" \
	    "\\^done,.*value=\"$hex.*" \
	    "create varobj for 'global_zero + \$pc' in frame $i"
	incr varnum
    }

    # Step one instruction to change the program counter.
    mi_execute_to "exec-next-instruction" "end-stepping-range" \
	"callee3" ".*" ".*${srcfile}" ".*" "" \
	"next instruction in callee3"

    # Check that -var-update reports that the values are changed for
    # varobj in frame 0.
    for {set i 1} {$i < $first_unchanging_varnum} {incr i} {
	mi_gdb_test "-var-update 1 var$i" \
	    "\\^done,(changelist=\\\[\{name=\"var$i\"\[^\\\]\]+\\\])" \
	    "varobj var$i has changed"
    }

    # Check that -var-update reports that the values are unchanged for
    # varobj in frames other than 0.
    for {set i $first_unchanging_varnum} {$i < $varnum} {incr i} {
	mi_gdb_test "-var-update 1 var$i" \
	    "\\^done,(changelist=\\\[\\\])" \
	    "varobj var$i has not changed"
    }
}

do_fixed_varobj_test
do_floating_varobj_test