# Copyright 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/>.

# Check that the unwinder produces consistent frame info, by making
# sure that "info frame" shows the same result when stopped at a
# function (level == 0), compared to when we find the same frame in
# the stack at a level > 0.  Tests both the DWARF stack unwinder, and
# the fallback heuristic unwinder.

standard_testfile backtrace.c

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

# Unwind to each function in FRAMES, and compare "info frame" output
# to what was saved in the 'info_frame_before' array.
proc compare_frames {frames} {
    foreach_with_prefix compare_frame $frames {
	if {[gdb_test \
		 "frame function $compare_frame" \
		 " $compare_frame .*"] != 0} {
	    continue
	}
	set info_frame_after ""
	gdb_test_multiple "info frame" "" {
	    -re "(.*\r\n$::gdb_prompt $)" {
		set info_frame_after $expect_out(1,string)
		pass $gdb_test_name
	    }
	}

	# Nuke the PC address, since it'll be different.  The
	# first time it's the actual PC before the call, the
	# second time it's the resume address after the call
	# returns.
	# E.g., on x86-64:
	#   rip = 0x555555555168 in main (gdb.base/backtrace.c:41); saved rip = 0x7ffff7dd90b3
	# vs
	#   rip = 0x555555555172 in main (gdb.base/backtrace.c:41); saved rip = 0x7ffff7dd90b3
	#
	set from \
	    "= $::hex in $compare_frame "
	set to \
	    "= \$hex in $compare_frame "
	regsub $from $::info_frame_before($compare_frame) $to \
	    ::info_frame_before($compare_frame)
	regsub $from $info_frame_after $to \
	    info_frame_after

	# Remove the "caller of frame at" line, which didn't
	# appear the first time, since the frame hadn't called any
	# other function yet then.
	regsub "\r\n caller of frame at $::hex\r\n" \
	    $info_frame_after "\r\n" \
	    info_frame_after
	regsub ", caller of frame at $::hex" \
	    $info_frame_after "" \
	    info_frame_after

	# "Stack level 0/1/2/3" -> "Stack level N"
	set from \
	    "Stack level $::decimal"
	set to \
	    "Stack level N"
	regsub $from $::info_frame_before($compare_frame) $to \
	    ::info_frame_before($compare_frame)
	regsub $from $info_frame_after $to \
	    info_frame_after

	# For debugging.
	verbose -log "BEFORE:\n$::info_frame_before($compare_frame)"
	verbose -log "AFTER:\n$info_frame_after"

	gdb_assert {[string match \
			 $::info_frame_before($compare_frame)\
			 $info_frame_after]} \
	    "info frame before/after match"
    }
}

proc test {dwarf_unwinder} {

    clean_restart $::binfile

    gdb_test_no_output "maint set dwarf unwinder $dwarf_unwinder"

    if ![runto_main] then {
	fail "can't run to main"
	return 0
    }

    array unset ::info_frame_before

    # Run to each function, and record "info frame" output in the
    # 'info_frame_before' array.  At each stop, unwind to each
    # already-recorded function, and compare "info frame" output to
    # what was saved in the 'info_frame_before' array.
    set funcs {"main" "foo" "bar" "baz"}
    set idx_funcs 0
    foreach_with_prefix stop_func $funcs {
	if {$idx_funcs != 0} {
	    gdb_breakpoint $stop_func
	    gdb_continue_to_breakpoint ".*$stop_func \(\).*"
	}

	set ::info_frame_before($stop_func) ""
	gdb_test_multiple "info frame" "" {
	    -re "(.*\r\n$::gdb_prompt $)" {
		set ::info_frame_before($stop_func) $expect_out(1,string)
		pass $gdb_test_name
	    }
	}

	if {$idx_funcs != 0} {
	    compare_frames [lreverse [lrange $funcs 0 $idx_funcs-1]]
	}
	incr idx_funcs
    }
}

foreach_with_prefix dwarf {"off" "on"} {
    test $dwarf
}