gdb/testsuite/gdb.dwarf2/dw2-ranges-func.exp

# 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/>.
load_lib dwarf.exp

# Test DW_AT_ranges in the context of a subprogram scope.

# This test can only be run on targets which support DWARF-2 and use gas.
if {![dwarf2_support]} {
    unsupported "dwarf2 support required for this test"
    return 0
}

if [get_compiler_info] {
    return -1
}
if !$gcc_compiled {
    unsupported "gcc required for this test"
    return 0
}

proc do_test {suffix} {
    global gdb_test_file_name
    global testfile binfile srcfile srcfile2 gdb_prompt hex

    # Don't use standard_testfile; we want different binaries for
    # each suffix.
    set testfile $gdb_test_file_name-$suffix
    set binfile [standard_output_file ${testfile}]
    set srcfile $testfile.c
    set srcfile2 $testfile-dw2.S

    # We need to know the size of integer and address types in order to
    # write some of the debugging info we'd like to generate.
    #
    # For that, we ask GDB by debugging our test program.  Any program
    # would do, but since we already have it specifically for this
    # testcase, might as well use that.

    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 srcfile2
	declare_labels integer_label volatile_label func_ranges_label cu_ranges_label L
	set int_size [get_sizeof "int" 4]

	# Find start address and length for our functions.
	lassign [function_range main [list ${srcdir}/${subdir}/$srcfile]] \
	    main_start main_len
	set main_end "$main_start + $main_len"
	lassign [function_range foo [list ${srcdir}/${subdir}/$srcfile]] \
	    foo_start foo_len
	set foo_end "$foo_start + $foo_len"
	lassign [function_range foo_cold [list ${srcdir}/${subdir}/$srcfile]] \
	    foo_cold_start foo_cold_len
	set foo_cold_end "$foo_cold_start + $foo_cold_len"
	lassign [function_range bar [list ${srcdir}/${subdir}/$srcfile]] \
	    bar_start bar_len
	set bar_end "$bar_start + $bar_len"
	lassign [function_range baz [list ${srcdir}/${subdir}/$srcfile]] \
	    baz_start baz_len
	set baz_end "$baz_start + $baz_len"

	set e_var [gdb_target_symbol e]

	cu {} {
	    compile_unit {
		{language @DW_LANG_C}
		{name dw-ranges-func2.c}
		{stmt_list $L DW_FORM_sec_offset}
		{low_pc 0 addr}
		{ranges ${cu_ranges_label} DW_FORM_sec_offset}
	    } {
		integer_label: DW_TAG_base_type {
		    {DW_AT_byte_size $int_size DW_FORM_sdata}
		    {DW_AT_encoding  @DW_ATE_signed}
		    {DW_AT_name      integer}
		}
		volatile_label: DW_TAG_volatile_type {
		    {type :$integer_label}
		}
		DW_TAG_variable {
		    {name e}
		    {external 1 flag}
		    {type :$volatile_label}
		    {location {addr $e_var} SPECIAL_expr}
		}
		subprogram {
		    {external 1 flag}
		    {name main}
		    {DW_AT_type :$integer_label}
		    {low_pc $main_start addr}
		    {high_pc $main_len DW_FORM_data4}
		}
		subprogram {
		    {external 1 flag}
		    {name foo}
		    {ranges ${func_ranges_label} DW_FORM_sec_offset}
		}
		subprogram {
		    {external 1 flag}
		    {name bar}
		    {low_pc $bar_start addr}
		    {high_pc $bar_len DW_FORM_data4}
		}
		subprogram {
		    {external 1 flag}
		    {name baz}
		    {low_pc $baz_start addr}
		    {high_pc $baz_len DW_FORM_data4}
		}
	    }
	}

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

	    # Generate a line table program.  An attempt was made to make it
	    # reasonably accurate as it made debugging the test case easier.
	    program {
		{DW_LNE_set_address $main_start}
		{line [gdb_get_line_number "main prologue"]}
		{DW_LNS_copy}
		{DW_LNE_set_address main_label}
		{line [gdb_get_line_number "main foo call"]}
		{DW_LNS_copy}
		{DW_LNE_set_address main_label2}
		{line [gdb_get_line_number "main return"]}
		{DW_LNS_copy}
		{DW_LNE_set_address $main_end}
		{line [expr [gdb_get_line_number "main end"] + 1]}
		{DW_LNS_copy}
		{DW_LNE_end_sequence}

		{DW_LNE_set_address $foo_start}
		{line [gdb_get_line_number "foo prologue"]}
		{DW_LNS_copy}
		{DW_LNE_set_address foo_label}
		{line [gdb_get_line_number "foo bar call"]}
		{DW_LNS_copy}
		{DW_LNE_set_address foo_label2}
		{line [gdb_get_line_number "foo foo_cold call"]}
		{DW_LNS_copy}
		{DW_LNE_set_address foo_label3}
		{line [gdb_get_line_number "foo end"]}
		{DW_LNS_copy}
		{DW_LNE_set_address $foo_end}
		{DW_LNS_advance_line 1}
		{DW_LNS_copy}
		{DW_LNE_end_sequence}

		{DW_LNE_set_address $bar_start}
		{line [gdb_get_line_number "bar end"]}
		{DW_LNS_copy}
		{DW_LNS_advance_pc $bar_len}
		{DW_LNS_advance_line 1}
		{DW_LNS_copy}
		{DW_LNE_end_sequence}

		{DW_LNE_set_address $baz_start}
		{line [gdb_get_line_number "baz end"]}
		{DW_LNS_copy}
		{DW_LNS_advance_pc $baz_len}
		{DW_LNS_advance_line 1}
		{DW_LNS_copy}
		{DW_LNE_end_sequence}

		{DW_LNE_set_address $foo_cold_start}
	        {line [gdb_get_line_number "foo_cold prologue"]}
		{DW_LNS_copy}
		{DW_LNE_set_address foo_cold_label}
		{line [gdb_get_line_number "foo_cold baz call"]}
		{DW_LNS_copy}
		{DW_LNE_set_address foo_cold_label2}
		{line [gdb_get_line_number "foo_cold end"]}
		{DW_LNS_copy}
		{DW_LNE_set_address $foo_cold_end}
		{DW_LNS_advance_line 1}
		{DW_LNS_copy}
		{DW_LNE_end_sequence}
	    }
	}

	# Generate ranges data.
	ranges {is_64 [is_64_target]} {
	    func_ranges_label: sequence {
		range $foo_start $foo_end
		range $foo_cold_start $foo_cold_end
	    }
	    cu_ranges_label: sequence {
		range $foo_start $foo_end
		range $foo_cold_start $foo_cold_end
		range $main_start $main_end
		range $bar_start $bar_end
		range $baz_start $baz_end
	    }
	}
    }

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

    if ![runto_main] {
	return -1
    }

    set main_prologue_line_num [gdb_get_line_number "main prologue"]
    # Do a sanity check to make sure that line number info is available.
    gdb_test "info line main" \
	"Line ${main_prologue_line_num} of .* starts at address .* and ends at .*"

    with_test_prefix "step-test-1" {
	set bp_foo_bar [gdb_get_line_number "foo bar call"]

	gdb_test "break $bp_foo_bar" \
	    "Breakpoint.*at.* file .*$srcfile, line $bp_foo_bar\\." \
	    "break at call to bar"

	gdb_test "continue" \
	    "Continuing\\..*Breakpoint \[0-9\]+, foo \\(\\).*$bp_foo_bar\\s+bar\\s\\(\\);.*foo bar call.*" \
	    "continue to call of bar"

	gdb_test "step" \
	    "bar \\(\\).*bar end.*" \
	    "step into bar"

	gdb_test "step" \
	    "foo \\(\\).*foo foo_cold call.*" \
	    "step out of bar, back into foo"
    }

    with_test_prefix "step-test-2" {
	clean_restart ${testfile}
	if ![runto_main] {
	    return -1
	}

	# Note that the RE used for the following test will fail when the
	# breakpoint has been set on multiple locations. E.g. "(2 locations)". 
	# This is intentional since that behavior is one of the bugs that
	# this test case tests for.
	gdb_test "break foo" \
	    "Breakpoint.*at.* file .*$srcfile, line \\d+\\."

	# Continue to foo.  Allow execution to stop either on the prologue
	# or on the call to bar since either behavior is acceptable though
	# the latter is preferred.
	set test "continue to foo"
	gdb_test_multiple "continue" $test {
	    -re "Breakpoint \\d+, foo \\(\\).*foo prologue.*${gdb_prompt}" {
		pass $test
		gdb_test "step" \
			 "foo bar call .*" \
			 "step to call of bar after landing on prologue"
	    }
	    -re "Breakpoint \\d+, foo \\(\\).*foo bar call.*${gdb_prompt}" {
		pass $test
	    }
	}

	gdb_test "step" \
	    "bar \\(\\).*bar end.*" \
	    "step into bar"

	gdb_test "step" \
	    "foo \\(\\).*foo foo_cold call.*" \
	    "step out of bar, back into foo"
    }

    clean_restart ${testfile}
    if ![runto_main] {
	return -1
    }

    # Disassembly of foo should have multiple address ranges.
    gdb_test_sequence "disassemble foo" "" [list \
	"Dump of assembler code for function foo:" \
	"Address range $hex to $hex:" \
	"   $hex <\\+0>:" \
	"Address range $hex to $hex:" \
	"   $hex <(.+?)>:" \
	"End of assembler dump\\." \
    ]

    set foo_cold_addr -1
    set test "x/i foo_cold"
    gdb_test_multiple $test $test {
	-re "   ($hex) <foo.*?>.*${gdb_prompt}" {
	    set foo_cold_addr $expect_out(1,string)
	    pass $test
	}
    }

    set foo_addr -1
    set test "x/i foo"
    gdb_test_multiple $test $test {
	-re "   ($hex) <foo.*?>.*${gdb_prompt}" {
	    set foo_addr $expect_out(1,string)
	    pass $test
	}
    }

    gdb_assert {$foo_cold_addr != $foo_addr} "foo and foo_cold are at different addresses"

    # This more permissive RE for "break foo" will allow a breakpoint on
    # multiple locations to PASS.  */
    gdb_test "break foo" \
	"Breakpoint.*at.*"

    gdb_test "break baz" \
	"Breakpoint.*at.* file .*$srcfile, line \\d+\\."

    gdb_test "continue" \
	"Breakpoint \\d+, foo \\(\\).*" \
	"continue to foo"

    gdb_test_no_output "set variable e=1"

    # If GDB incorrectly places the foo breakpoint on multiple locations,
    # then GDB will (incorrectly) stop in foo_cold instead of in baz.
    gdb_test "continue" \
	"Breakpoint \\d+, (?:$hex in )?baz \\(\\).*" \
	"continue to baz"

    with_test_prefix "no-cold-names" {

	# Due to the calling sequence, this backtrace would normally
	# show function foo_cold for frame #1.  However, we don't want
	# this to be the case due to placing it in the same block
	# (albeit at a different range) as foo.  Thus it is correct to
	# see foo for frames #1 and #2.  It is incorrect to see
	# foo_cold at frame #1.
	gdb_test_sequence "bt" "backtrace from baz" {
	    "\[\r\n\]#0 .*? baz \\(\\) "
	    "\[\r\n\]#1 .*? foo \\(\\) "
	    "\[\r\n\]#2 .*? foo \\(\\) "
	    "\[\r\n\]#3 .*? main \\(\\) "
	}

	# Doing x/2i foo_cold should show foo_cold as the first symbolic
	# address and an offset from foo for the second.  We also check to
	# make sure that the offset is not too large - we don't GDB to
	# display really large offsets that would (try to) wrap around the
	# address space.
	set foo_cold_offset 0
	set test "x/2i foo_cold"
	gdb_test_multiple $test $test {
	    -re "   (?:$hex) <foo_cold>.*?\n   (?:$hex) <foo\[+-\](\[0-9\]+)>.*${gdb_prompt}" {
	        set foo_cold_offset $expect_out(1,string)
		pass $test
	    }
	}
	gdb_assert {$foo_cold_offset <= 10000} "offset to foo_cold is not too large"

	# Likewise, verify that second address shown by "info line" is at
	# and offset from foo instead of foo_cold.
	gdb_test "info line *foo_cold" "starts at address $hex <foo_cold> and ends at $hex <foo\[+-\].*?>.*"

    }

    with_test_prefix "step-test-3" {
	clean_restart ${testfile}
	if ![runto_main] {
	    return -1
	}

	gdb_test "step" \
		 "foo \\(\\).*bar \\(\\);.*foo bar call.*" \
		 "step into foo from main"

	gdb_test "step" \
		 "bar \\(\\).*\}.* bar end.*" \
		 "step into bar from foo"

	gdb_test "step" \
		 "foo(_label2)? \\(\\).*foo_cold \\(\\);.*foo foo_cold call.*" \
		 "step out of bar to foo"

	# Tests in the "enable_foo_cold_stepping" section, below, did
	# not work prior to July, 2019.  They had been disabled via
	# use of the "enable_foo_cold_stepping" flag.
	# 
	# As noted elsewhere, this test case causes foo_cold,
	# originally a separate function invoked via a subroutine
	# call, to be considered as part of foo via use of
	# DW_AT_ranges.  Real code that I've looked at uses a branch
	# instruction to cause code in the "cold" range to be
	# executed.  These tests used to fail which is why they were
	# disabled.
	#
	# After adding a "hi" cold test, I found that we were able to
	# step into foo_cold from foo for the "hi" version, but for
	# the "lo" version, GDB would run to either the next
	# breakpoint or until the inferior exited when there were no
	# breakpoints.  Not being able to step is definitely a bug
	# even if it's unlikely that this problem would ever be hit in
	# a real program.  Therefore, the bug was fixed in GDB and
	# these tests are now enabled.
	#
	# I've left in place the flag (and test) which may be used to
	# disable these tests.

	set enable_foo_cold_stepping true

	if { $enable_foo_cold_stepping } {
	    gdb_test_no_output "set variable e=1"

	    set test "step into foo_cold from foo"
	    gdb_test_multiple "step" $test {
		-re "foo(_low)? \\(\\).*\{.*foo_cold prologue.*${gdb_prompt}" {
		    pass $test
		    gdb_test "step" \
			     "foo \\(\\).*baz \\(\\);.*foo_cold baz call.*" \
			     "step to baz call in foo_cold"

		}
		-re "foo(_cold)? \\(\\).*baz \\(\\);.*foo_cold baz call.*${gdb_prompt}" {
		    pass $test
		}
	    }

	    gdb_test "step" \
		     "baz \\(\\).*\}.*baz end.*" \
		     "step into baz from foo_cold"

	    gdb_test "step" \
		     "foo(?:_low(?:_label2)?)? \\(\\).*\}.*foo_cold end.*" \
		     "step out of baz to foo_cold"

	    gdb_test "step" \
		     "foo(?:_label3)? \\(\\).*\}.*foo end.*" \
		     "step out of foo_cold to foo"
	} else {
	    gdb_test "next" \
		     ".*foo end.*" \
		     "next over foo_cold call"
	}

	gdb_test "step" \
		 "main(?:_label2)? \\(\\).*" \
		 "step out of foo to main"
    }
}

# foreach_with_prefix could be used here, but the log file output is somewhat
# less verbose when using an explicit "with_test_prefix".

foreach test_suffix { "lo-cold" "hi-cold" } {
    with_test_prefix $test_suffix {
	do_test $test_suffix
    }
}