gdb/testsuite/gdb.base/cached-source-file.exp

# Copyright (C) 2020-2024 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 for PR tui/25126.
#
# The bug is about a regression that makes GDB not reload its source
# code cache when the inferior's symbols are reloaded, which leads to
# wrong backtraces/listings.
#
# This bug is reproducible even without using the TUI.

standard_testfile

# Only run on native boards.
require !use_gdb_stub
if { [target_info gdb_protocol] == "extended-remote" } {
    return -1
}

# Because we need to modify the source file later, it's better if we
# just copy it to our output directory (instead of messing with the
# user's source directory).
set newsrc [standard_output_file $testfile].c
file copy -force -- $srcdir/$subdir/$srcfile $newsrc
set srcfile $newsrc

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

# Get the line number for the line with the "break-here" marker.
set bp_line [gdb_get_line_number "break-here" $srcfile]

gdb_assert { [runto "$srcfile:$bp_line"] } \
    "run to break-here marker"

# Do a "list" and check that the printed line matches the line of the
# original source file.
gdb_test_no_output "set listsize 1"
gdb_test "list" "$bp_line\[ \t\]+printf \\(\"hello\\\\n\"\\); /\\* break-here \\*/" \
    "check the first version of the source file"

# Modify the original source file, and add an extra line into it.
# This only works locally because of the TCL commands.
set bkpsrc [standard_output_file $testfile].c.bkp
set bkpsrcfd [open $bkpsrc w]
set srcfd [open $srcfile r]

while { [gets $srcfd line] != -1 } {
    if { [string first "break-here" $line] != -1 } {
	# Put a "printf" line before the "break-here" line.
	puts $bkpsrcfd "  printf (\"foo\\n\"); /* new-marker */"
    }
    puts $bkpsrcfd $line
}

close $bkpsrcfd
close $srcfd
file rename -force -- $bkpsrc $srcfile
# We have to wait 1 second because of the way GDB checks whether the
# binary has changed or not.  GDB uses stat(2) and currently checks
# 'st_mtime', whose precision is measured in seconds.  Since the copy,
# rename, and rebuild can take less than 1 second, GDB might mistakenly
# assume that the binary is unchanged.
sleep 1

# Recompile the modified source.  We use "gdb_compile" here instead of
# "prepare_for_testing" because we don't want to call "clean_restart".
if { [gdb_compile "${srcfile}" "${binfile}" executable {debug}] != "" } {
    return -1
}

# Rerun the program.  This should not only force GDB to reload the
# source cache, but also to break at BP_LINE again, which now has
# different contents.
set q \
    [multi_line \
	 "The program being debugged has been started already\\." \
	 "Start it from the beginning\\? \\(y or n\\) "]
set binregex [string_to_regexp $binfile]
set re \
    [multi_line \
	 "\\`$binregex\\' has changed; re-reading symbols\\.(" \
	 "Expanding full symbols from $binfile\\.\\.\\.)?" \
	 "Starting program: ${binregex}.*"]
gdb_test "run" $re "rerun program" $q y

# Again, perform the listing and check that the line indeed has
# changed for GDB.
gdb_test "list" "${bp_line}\[ \t\]+printf \\(\"foo\\\\n\"\\); /\\\* new-marker \\\*/.*" \
    "verify that the source code is properly reloaded"

# Modify the source file again.  As before, this only works locally
# because of the TCL commands.
set bkpsrc [standard_output_file $testfile].c.bkp
set bkpsrcfd [open $bkpsrc w]
set srcfd [open $srcfile r]

while { [gets $srcfd line] != -1 } {
    if { [string first "new-marker" $line] != -1 } {
	# Modify the printf line that we added previously.
	puts $bkpsrcfd "  printf (\"foo\\n\"); /* new-marker updated */"
    } else {
	puts $bkpsrcfd $line
    }
}

close $bkpsrcfd
close $srcfd
file rename -force -- $bkpsrc $srcfile

# As before, delay so that at least one second has passed.  GDB still
# will not spot that the source file has changed, as GDB doesn't do a
# time check unless the binary has also changed, this delay just
# allows us to confirm this behaviour.
sleep 1

# List the printf line again, we should not see the file changes yet
# as the binary is unchanged, so the cached contents will still be
# used.
gdb_test "list ${bp_line}" "${bp_line}\[ \t\]+printf \\(\"foo\\\\n\"\\); /\\\* new-marker \\\*/.*" \
    "verify that the source code change is not seen yet"

gdb_test "maint flush source-cache" "Source cache flushed\\."

# List the printf line again.  After the cache flush GDB will re-read
# the source file and we should now see the changes.
gdb_test "list ${bp_line}" "${bp_line}\[ \t\]+printf \\(\"foo\\\\n\"\\); /\\\* new-marker updated \\\*/.*" \
    "verify that the updated source code change is not seen"