binutils-gdb/gdb/contrib/cc-with-tweaks.sh
Simon Marchi a9eac7f9b4 cc-with-tweaks: show dwz stderr and verify result
When running the gdb.base/index-cache.exp test case with the
cc-with-dwz-m board, I noticed that the final executable didn't actually
contain a .gnu_debugaltlink section with the name of the external dwz
file:

    $ readelf --debug-dump=links testsuite/outputs/gdb.base/index-cache/index-cache
    * empty *

Running dwz by hand, I realized it's because dwz complains that the
output .debug_info section is empty and fails:

    $ gcc ~/src/binutils-gdb/gdb/testsuite/gdb.base/index-cache.c -g3 -O0 -o a && cp a b
    $ dwz -m foo a b
    dwz: foo: .debug_info section not present
    $ echo $?
    1

This is because index-cache.c is trivial (just an empty main) and dwz
doesn't find anything to factor out to the dwz file. [1]

I think that cc-with-tweaks should fail in this scenario: if the user
asks for an external dwz file to be generated (the -m flag), then it
should be an error if cc-with-tweaks doesn't manage to produce an
executable with the proper link to this external dwz file.  Otherwise,
the test runs with a regular non-dwzified executable, which gives a
false sense of security about whether the feature under test works with
dwzified executables.

So this patch adds checks for that after invoking dwz.  It also removes
the 2>&1 to allow the error message to be printed like so:

    Running /home/smarchi/src/binutils-gdb/gdb/testsuite/gdb.base/index-cache.exp ...
    gdb compile failed, dwz: /home/smarchi/build/binutils-gdb/gdb/testsuite/outputs/gdb.base/index-cache/index-cache.dwz: .debug_info section not present

- In the -m case (multi-file compression), we check if the expected output file
  exists.
- In the -z case (single-file compression), we check if the file
  contents has changed.  This should catch cases where dwz doesn't modify the
  file because it's not worth it.

It was chosen not to check for dwz's exit code, as it is not very
reliable up to dwz 0.12.

With this patch, fewer tests will pass than before with the
cc-with-dwz and cc-with-dwz-m boards, but those were false positives
anyway, as the test ran with regular executables.

[1] Note that dwz has been patched by Tom de Vries to work correctly in
this case, so we can use dwz master to run the test:

https://sourceware.org/git/?p=dwz.git;a=commit;h=08becc8b33453b6d013a65e7eeae57fc1881e801

gdb/ChangeLog:

	* contrib/cc-with-tweaks.sh: Validate dwz's work.
2019-05-10 16:29:40 -04:00

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#!/usr/bin/env bash
# Wrapper around gcc to tweak the output in various ways when running
# the testsuite.
# Copyright (C) 2010-2019 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 program requires gdb and objcopy in addition to gcc.
# The default values are gdb from the build tree and objcopy from $PATH.
# They may be overridden by setting environment variables GDB and OBJCOPY
# respectively. Note that GDB should contain the gdb binary as well as the
# -data-directory flag, e.g., "foo/gdb -data-directory foo/data-directory".
# We assume the current directory is either $obj/gdb or $obj/gdb/testsuite.
#
# Example usage:
#
# bash$ cd $objdir/gdb/testsuite
# bash$ runtest \
# CC_FOR_TARGET="/bin/bash $srcdir/gdb/contrib/cc-with-tweaks.sh ARGS gcc" \
# CXX_FOR_TARGET="/bin/bash $srcdir/gdb/contrib/cc-with-tweaks.sh ARGS g++"
#
# For documentation on Fission and dwp files:
# http://gcc.gnu.org/wiki/DebugFission
# http://gcc.gnu.org/wiki/DebugFissionDWP
# For documentation on index files: info -f gdb.info -n "Index Files"
# For information about 'dwz', see the announcement:
# http://gcc.gnu.org/ml/gcc/2012-04/msg00686.html
# (More documentation is to come.)
# ARGS determine what is done. They can be:
# -Z invoke objcopy --compress-debug-sections
# -z compress using dwz
# -m compress using dwz -m
# -i make an index (.gdb_index)
# -n make a dwarf5 index (.debug_names)
# -p create .dwp files (Fission), you need to also use gcc option -gsplit-dwarf
# If nothing is given, no changes are made
myname=cc-with-tweaks.sh
mydir=`dirname "$0"`
if [ -z "$GDB" ]
then
if [ -f ./gdb ]
then
GDB="./gdb -data-directory data-directory"
elif [ -f ../gdb ]
then
GDB="../gdb -data-directory ../data-directory"
elif [ -f ../../gdb ]
then
GDB="../../gdb -data-directory ../../data-directory"
else
echo "$myname: unable to find usable gdb" >&2
exit 1
fi
fi
OBJCOPY=${OBJCOPY:-objcopy}
READELF=${READELF:-readelf}
DWZ=${DWZ:-dwz}
DWP=${DWP:-dwp}
have_link=unknown
next_is_output_file=no
output_file=a.out
want_index=false
index_options=""
want_dwz=false
want_multi=false
want_dwp=false
want_objcopy_compress=false
while [ $# -gt 0 ]; do
case "$1" in
-Z) want_objcopy_compress=true ;;
-z) want_dwz=true ;;
-i) want_index=true ;;
-n) want_index=true; index_options=-dwarf-5;;
-m) want_multi=true ;;
-p) want_dwp=true ;;
*) break ;;
esac
shift
done
if [ "$want_index" = true ]
then
if [ -z "$GDB_ADD_INDEX" ]
then
if [ -f $mydir/gdb-add-index.sh ]
then
GDB_ADD_INDEX="$mydir/gdb-add-index.sh"
else
echo "$myname: unable to find usable contrib/gdb-add-index.sh" >&2
exit 1
fi
fi
fi
for arg in "$@"
do
if [ "$next_is_output_file" = "yes" ]
then
output_file="$arg"
next_is_output_file=no
continue
fi
# Poor man's gcc argument parser.
# We don't need to handle all arguments, we just need to know if we're
# doing a link and what the output file is.
# It's not perfect, but it seems to work well enough for the task at hand.
case "$arg" in
"-c") have_link=no ;;
"-E") have_link=no ;;
"-S") have_link=no ;;
"-o") next_is_output_file=yes ;;
esac
done
if [ "$next_is_output_file" = "yes" ]
then
echo "$myname: Unable to find output file" >&2
exit 1
fi
if [ "$have_link" = "no" ]
then
"$@"
exit $?
fi
index_file="${output_file}.gdb-index"
if [ "$want_index" = true ] && [ -f "$index_file" ]
then
echo "$myname: Index file $index_file exists, won't clobber." >&2
exit 1
fi
output_dir="${output_file%/*}"
[ "$output_dir" = "$output_file" ] && output_dir="."
"$@"
rc=$?
[ $rc != 0 ] && exit $rc
if [ ! -f "$output_file" ]
then
echo "$myname: Internal error: $output_file missing." >&2
exit 1
fi
if [ "$want_objcopy_compress" = true ]; then
$OBJCOPY --compress-debug-sections "$output_file"
rc=$?
[ $rc != 0 ] && exit $rc
fi
if [ "$want_index" = true ]; then
# Filter out these messages which would stop dejagnu testcase run:
# echo "$myname: No index was created for $file" 1>&2
# echo "$myname: [Was there no debuginfo? Was there already an index?]" 1>&2
GDB=$GDB $GDB_ADD_INDEX $index_options "$output_file" 2>&1 \
| grep -v "^${GDB_ADD_INDEX##*/}: " >&2
rc=${PIPESTATUS[0]}
[ $rc != 0 ] && exit $rc
fi
if [ "$want_dwz" = true ]; then
# Validate dwz's result by checking if the executable was modified.
cp "$output_file" "${output_file}.copy"
$DWZ "$output_file" > /dev/null
cmp "$output_file" "$output_file.copy" > /dev/null
cmp_rc=$?
rm -f "${output_file}.copy"
case $cmp_rc in
0)
echo "$myname: dwz did not modify ${output_file}."
exit 1
;;
1)
# File was modified, great.
;;
*)
# Other cmp error, it presumably has already printed something on
# stderr.
exit 1
;;
esac
elif [ "$want_multi" = true ]; then
# Remove the dwz output file if it exists, so we don't mistake it for a
# new file in case dwz fails.
rm -f "${output_file}.dwz"
cp $output_file ${output_file}.alt
$DWZ -m ${output_file}.dwz "$output_file" ${output_file}.alt > /dev/null
rm -f ${output_file}.alt
# Validate dwz's work by checking if the expected output file exists.
if [ ! -f "${output_file}.dwz" ]; then
echo "$myname: dwz file ${output_file}.dwz missing."
exit 1
fi
fi
if [ "$want_dwp" = true ]; then
dwo_files=$($READELF -wi "${output_file}" | grep _dwo_name | \
sed -e 's/^.*: //' | sort | uniq)
rc=0
if [ -n "$dwo_files" ]; then
$DWP -o "${output_file}.dwp" ${dwo_files} > /dev/null
rc=$?
[ $rc != 0 ] && exit $rc
rm -f ${dwo_files}
fi
fi
rm -f "$index_file"
exit $rc