testsuite/gdb.dwarf2/dw2-is-stmt.exp

# Copyright 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/>.

# This test shows the importance of not corrupting the order of line
# table information.  When multiple lines are given for the same
# address the compiler usually lists these in the order in which we
# would expect to encounter them.  When stepping through nested inline
# frames the last line given for an address is assumed by GDB to be
# the most inner frame, and this is what GDB displays.
#
# If we corrupt the order of the line table entries then GDB will
# display the wrong line as being the inner most frame.

load_lib dwarf.exp

# This test can only be run on targets which support DWARF-2 and use gas.
if {![dwarf2_support]} {
    return 0
}

# The .c files use __attribute__.
if [get_compiler_info] {
    return -1
}
if !$gcc_compiled {
    return 0
}

standard_testfile dw2-is-stmt.c dw2-is-stmt.S

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

    get_func_info main

    cu {} {
	compile_unit {
	    {language @DW_LANG_C}
	    {name dw2-is-stmt.c}
	    {low_pc 0 addr}
	    {stmt_list ${lines_label} DW_FORM_sec_offset}
	} {
	    subprogram {
		{external 1 flag}
		{name main}
		{low_pc $main_start addr}
		{high_pc "$main_start + $main_len" addr}
	    } {}
	}
    }

    lines {version 2 default_is_stmt 0} lines_label {
	include_dir "${srcdir}/${subdir}"
	file_name "$srcfile" 1

	program {
	    {DW_LNE_set_address main}
	    {line [gdb_get_line_number "main prologue"]}
	    {DW_LNS_negate_stmt}
	    {DW_LNS_copy}

	    {DW_LNE_set_address line_label_1}
	    {line [gdb_get_line_number "main, set var to 99"]}
	    {DW_LNS_copy}

	    {DW_LNE_set_address line_label_2}
	    {line [gdb_get_line_number "main, set var to 0"]}
	    {DW_LNS_negate_stmt}
	    {DW_LNS_copy}

	    {DW_LNE_set_address line_label_3}
	    {DW_LNS_negate_stmt}
	    {DW_LNS_copy}

	    {DW_LNE_set_address line_label_4}
	    {DW_LNS_negate_stmt}
	    {DW_LNS_copy}

	    {DW_LNE_set_address line_label_5}
	    {line [gdb_get_line_number "main end"]}
	    {DW_LNS_negate_stmt}
	    {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 -1
}

# First, break by address at a location we know is marked as not a
# statement.  GDB should still correctly report the file and line
# number.
gdb_breakpoint "*line_label_2"
gdb_continue_to_breakpoint "*line_label_2"

# Now step by instruction.  We should skip over the is-stmt location
# for this line, and land on the next source line.
gdb_test "step" "/\\* main end \\*/" \
    "step to end from line_label_2"

# Restart the test.  This time, stop at a location we know is marked
# as a statement.
clean_restart ${binfile}
runto_main

gdb_breakpoint "*line_label_3"
gdb_continue_to_breakpoint "*line_label_3"

# Now step by instruction.  As you would expect we should leave this
# line and stop at the next source line.
gdb_test "step" "/\\* main end \\*/" \
    "step to end from line_label_3"

# Restart the test, this time, step through line by line, ensure we
# only stop at the places where is-stmt is true.
clean_restart ${binfile}
runto_main

# Get the values of the labels where we expect to stop.
set ll1 [get_hexadecimal_valueof "&line_label_1" "INVALID"]
set ll2 [get_hexadecimal_valueof "&line_label_2" "INVALID"]
set ll3 [get_hexadecimal_valueof "&line_label_3" "INVALID"]
set ll5 [get_hexadecimal_valueof "&line_label_5" "INVALID"]

# The first stop should be at line_label_1
with_test_prefix "check we're at line_label_1" {
    set pc [get_hexadecimal_valueof "\$pc" "NO-PC"]
    gdb_assert { $ll1 == $pc } "check initial \$pc is line_label_1"
}

# Now step, this should take us to line_label_3 which is the next
# location marked as is-stmt.
with_test_prefix "step to line_label_3" {
    gdb_test "step" "/\\* main, set var to 0 \\*/"
    set pc [get_hexadecimal_valueof "\$pc" "NO-PC"]
    gdb_assert { $ll3 == $pc } "check initial \$pc is line_label_3"
}

# A final step should take us to line_label_5.
with_test_prefix "step to line_label_5" {
    gdb_test "step" "/\\* main end \\*/"
    set pc [get_hexadecimal_valueof "\$pc" "NO-PC"]
    gdb_assert { $ll5 == $pc } "check initial \$pc"
}

# Now restart the test, and place a breakpoint by line number.  GDB
# should select the location that is marked as is-stmt.
clean_restart ${binfile}
runto_main
set linum [gdb_get_line_number "main, set var to 0"]
gdb_breakpoint "$srcfile:$linum"
gdb_continue_to_breakpoint "Breakpoint on line, set var to 0"
set pc [get_hexadecimal_valueof "\$pc" "NO-PC"]
gdb_assert { $ll3 == $pc } "check initial \$pc"

# Restart the test again, this time we will test stepping by
# instruction.
clean_restart ${binfile}
runto_main

# We will be at line_label_1 at this point - we already tested this
# above.  Now single instruction step forward until we get to
# line_label_2.  Every instruction before line_label_2 should be
# attributed to the 'var = 99' line.  For most targets there will only
# be a single instruction between line_label_1 and line_label_2, but
# we allow for up to 25 (just a random number).

set $i 0
set pc [get_hexadecimal_valueof "\$pc" "NO-PC" \
	   "get pc before stepi loop at line_label_1"]
while { $pc < $ll2 } {
    incr i
    set line_changed -1
    gdb_test_multiple "stepi" "stepi until line_label_2, $i" {
	-re "main, set var to 99.*$gdb_prompt" {
	    set line_changed 0
	}
	-re "main, set var to 0.*$gdb_prompt " {
	    set line_changed 1
	}
    }
    gdb_assert { $line_changed != -1 } \
	"ensure we saw a valid line pattern, $i"
    set pc [get_hexadecimal_valueof "\$pc" "NO-PC" \
		"get pc inside stepi loop from line_label_1, $i"]
    if { $ll2 == $pc } {
	gdb_assert { $line_changed } \
	    "line must change at line_label_2"
    } else {
	gdb_assert { !$line_changed } \
	    "line should not change until line_label_2, $i"
    }
}

# Now single instruction step forward until GDB reports a new source
# line, at which point we should be at line_label_5.

set $i 0
set pc [get_hexadecimal_valueof "\$pc" "NO-PC" \
	   "get pc before stepi loop at line_label_2"]
while { $pc < $ll5 } {
    incr i
    set line_changed -1
    gdb_test_multiple "stepi" "stepi until line_label_5, $i" {
	-re "main, set var to 0.*$gdb_prompt" {
	    set line_changed 0
	}
	-re "main end.*$gdb_prompt " {
	    set line_changed 1
	}
    }
    gdb_assert { $line_changed != -1 } \
	"ensure we saw a valid line pattern, $i"
    set pc [get_hexadecimal_valueof "\$pc" "NO-PC" \
		"get pc inside stepi loop from line_label_2, $i"]
    if { $ll5 == $pc } {
	gdb_assert { $line_changed } \
	    "line must change at line_label_5"
    } else {
	gdb_assert { !$line_changed } \
	    "line should not change until line_label_5, $i"
    }
}