gdb/testsuite/gdb.reverse/map-to-same-line.exp

# Copyright 2023-2025 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/>.

# When stepping (forwards or backwards), GDB should step over the entire line
# and not just a particular entry in the line table. This test was added to
# verify the find_line_range_start function properly sets the step range for a
# line that consists of multiple statements, i.e. multiple entries in the line
# table.  This test creates a DWARF line table that contains two entries for
# the same line to do the needed testing.

# This test can only be run on targets which support DWARF-2 and use gas.
load_lib dwarf.exp
require dwarf2_support

# The DWARF assembler requires the gcc compiler.
require is_c_compiler_gcc

# This test suitable only for process that can do reverse execution
require supports_reverse

standard_testfile .c .S

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

set asm_file [standard_output_file $srcfile2]
Dwarf::assemble $asm_file {
    global srcdir subdir srcfile
    declare_labels integer_label L

    # Find start address and length of program
    lassign [function_range main [list ${srcdir}/${subdir}/$srcfile]] \
	main_start main_len
    set main_end "$main_start + $main_len"

    cu {} {
	compile_unit {
	    {language @DW_LANG_C}
	    {name map-to-same-line.c}
	    {stmt_list $L DW_FORM_sec_offset}
	    {low_pc 0 addr}
	} {
	    subprogram {
		{external 1 flag}
		{name main}
		{low_pc $main_start addr}
		{high_pc $main_len DW_FORM_data4}
	    }
	}
    }

    lines {version 2 default_is_stmt 1} L {
	include_dir "${srcdir}/${subdir}"
	file_name "$srcfile" 1

	# Generate the line table program with distinct source lines being
	# mapped to the same line entry. Line 1, 5 and 8 contain 1 statement
	# each.  Line 2 contains 2 statements.  Line 3 contains 3 statements.
	program {
	    DW_LNE_set_address $main_start
	    line [gdb_get_line_number "TAG: main prologue"]
	    DW_LNS_copy
	    DW_LNE_set_address line1
	    line [gdb_get_line_number "TAG: line 1" ]
	    DW_LNS_copy
	    DW_LNE_set_address line2
	    line [gdb_get_line_number "TAG: line 2" ]
	    DW_LNS_copy
	    DW_LNE_set_address line3
	    line [gdb_get_line_number "TAG: line 2" ]
	    DW_LNS_copy
	    DW_LNE_set_address line4
	    line [gdb_get_line_number "TAG: line 3" ]
	    DW_LNS_copy
	    DW_LNE_set_address line5
	    line [gdb_get_line_number "TAG: line 3" ]
	    DW_LNS_copy
	    DW_LNE_set_address line6
	    line [gdb_get_line_number "TAG: line 3" ]
	    DW_LNS_copy
	    DW_LNE_set_address line7
	    line [gdb_get_line_number "TAG: line 5" ]
	    DW_LNS_copy
	    DW_LNE_set_address line8
	    line [gdb_get_line_number "TAG: line 8" ]
	    DW_LNS_copy
	    DW_LNE_set_address main_return
	    line [gdb_get_line_number "TAG: main return"]
	    DW_LNS_copy

	    DW_LNE_set_address $main_end
	    DW_LNE_end_sequence
	}
    }
}

if { [prepare_for_testing "failed to prepare" ${testfile} \
	[list $srcfile $asm_file] {nodebug} ] } {
    return -1
}

if { ![runto_main] } {
    return
}

# Print the line table
gdb_test_multiple "maint info line-table ${testfile}" "" {
    -re "\r\n$decimal\[ \t\]+$decimal\[ \t\]+($hex)\[ \t\]+Y\[^\r\n\]*" {
	lappend is_stmt $expect_out(1,string)
	exp_continue
    }
    -re -wrap "" {
    }
}

# Do the reverse-step and reverse-next tests
foreach_with_prefix cmd {step next} {
    gdb_test_no_output "record" "turn on process record, test $cmd"

    set bp_main_return [gdb_get_line_number "TAG: main return" $srcfile]
    gdb_breakpoint $srcfile:$bp_main_return
    gdb_continue_to_breakpoint  "run to end of main, reverse-$cmd test" ".*$srcfile:$bp_main_return.*"
    gdb_test "display \$pc" ".*pc =.*" "display pc, reverse-$cmd test"

    # At this point, GDB has already recorded the execution up until the return
    # statement.  Reverse and test if GDB transitions between lines in the
    # expected order.  It should reverse-step or reverse-next across lines 8,
    # 5, 3, 2 and 1.
    foreach line {8 5 3 2 1} {
	gdb_test "reverse-$cmd" ".*TAG: line $line.*" "reverse $cmd to line $line"
    }

    if {$cmd =="step"} {
	## Clean restart, test reverse-next command
	clean_restart ${testfile}

	if { ![runto_main] } {
	    return
	}
    }
}