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Re: [PATCH] Make ftrace tests work with remote targets
- From: Simon Marchi <simon dot marchi at ericsson dot com>
- To: gdb-patches <gdb-patches at sourceware dot org>
- Date: Fri, 11 Mar 2016 12:30:48 -0500
- Subject: Re: [PATCH] Make ftrace tests work with remote targets
- Authentication-results: sourceware.org; auth=none
- References: <1457040175-24438-1-git-send-email-simon dot marchi at ericsson dot com>
On 16-03-03 04:22 PM, Simon Marchi wrote:
> When we build a shared library for testing, it is built differently
> whether it is meant for the local system or a remote one. When it is
> for the local system, the library is built with no SONAME. So when the
> executable is built, roughly in this way:
>
> $ gcc testfile.c /path/to/library.so
>
> the executable will contain an absolute reference to the library. For
> example:
>
> $ readelf -a testsuite/gdb.python/py-shared | grep NEEDED
> 0x0000000000000001 (NEEDED) Shared library: [/home/emaisin/build/binutils-gdb/gdb/testsuite/gdb.python/py-shared-sl.sl]
>
> When testing is done remotely, the absolute path obviously doesn't work.
> Therefore, we build the library with an SONAME:
>
> $ readelf -a testsuite/gdb.python/py-shared-sl.sl | grep SONAME
> 0x000000000000000e (SONAME) Library soname: [py-shared-sl.sl]
>
> which ends up in the executable's NEEDED field:
>
> $ readelf -a testsuite/gdb.python/py-shared | grep NEEDED
> 0x0000000000000001 (NEEDED) Shared library: [py-shared-sl.sl]
>
> The executable and the library are then uploaded side-by-side on the
> remote system. To allow the dynamic linker to find the shared library,
> we have to add the special RPATH value $ORIGIN, which tells it to search
> in the executable's directory:
>
> $ readelf -a testsuite/gdb.python/py-shared | grep ORIGIN
> 0x000000000000000f (RPATH) Library rpath: [$ORIGIN]
>
> The problem with the IPA library is that it doesn't have an SONAME,
> making it very difficult to do testing on a remote board. When a
> test executable is linked with it, it contains an absolute reference to
> the library path. Therefore, unless the paths on the target are the
> same as on the build system, it won't work.
>
> To make it possible for tests using the IPA library to run test on
> remote boards, I suggest adding dding an SONAME to libinproctrace.so. I
> don't think it should be a big problem for users. All the libraries
> installed on my system have an SONAME, so it should be fine if
> libinproctrace.so does too.
>
> As a consequence, native testing does not work anymore, since
> executables do not contain the absolute path to the library anymore. To
> keep them working, we can have gdb_load_shlibs copy the library to the
> test directory when testing natively. That's done by modifying
> gdb_load_shlibs. We also have to add RPATH=$ORIGIN to executables, even
> when testing natively.
>
> I think it's a good change in general, as it reduces the differences
> between testing a native and a remote target. To further reduce those
> differences, we can also always build test shared libraries with an
> SONAME.
>
> ftrace.exp and ftrace-lock.exp need to be modified slightly. The code
> checks that the IPA library is loaded using the absolute path on the
> build machine. That obviously doesn't work if the test is done
> remotely, as the path will be different. I changed the tests to only
> search for the library basename (e.g. libinproctrace.so).
>
> gdb/gdbserver/ChangeLog:
>
> * Makefile.in ($(IPA_LIB)): Set SONAME of the IPA lib.
>
> gdb/testsuite/ChangeLog:
>
> * gdb.trace/ftrace-lock.exp: Check for IPA basename instead of
> absolute.
> * gdb.trace/ftrace.exp: Likewise.
> * lib/gdb.exp (gdb_compile): Set rpath $ORIGIN for non-remote
> targets as well.
> (gdb_compile_shlib): Set SONAME for non-remote targets as well.
> (gdb_load_shlibs): Copy libraries to test directory when testing
> natively.
> ---
> gdb/gdbserver/Makefile.in | 2 +-
> gdb/testsuite/gdb.trace/ftrace-lock.exp | 2 +-
> gdb/testsuite/gdb.trace/ftrace.exp | 2 +-
> gdb/testsuite/lib/gdb.exp | 27 ++++++++++++++++++++-------
> 4 files changed, 23 insertions(+), 10 deletions(-)
>
> diff --git a/gdb/gdbserver/Makefile.in b/gdb/gdbserver/Makefile.in
> index 1e874e3..c4324e3 100644
> --- a/gdb/gdbserver/Makefile.in
> +++ b/gdb/gdbserver/Makefile.in
> @@ -327,7 +327,7 @@ IPA_LIB=libinproctrace.so
>
> $(IPA_LIB): $(IPA_OBJS) ${ADD_DEPS} ${CDEPS}
> rm -f $(IPA_LIB)
> - $(CC_LD) -shared -fPIC -Wl,--no-undefined $(INTERNAL_CFLAGS) \
> + $(CC_LD) -shared -fPIC -Wl,--soname=$(IPA_LIB) -Wl,--no-undefined $(INTERNAL_CFLAGS) \
> $(INTERNAL_LDFLAGS) -o $(IPA_LIB) ${IPA_OBJS} -ldl -pthread
>
> # Put the proper machine-specific files first, so M-. on a machine
> diff --git a/gdb/testsuite/gdb.trace/ftrace-lock.exp b/gdb/testsuite/gdb.trace/ftrace-lock.exp
> index 0b73086..077a261 100644
> --- a/gdb/testsuite/gdb.trace/ftrace-lock.exp
> +++ b/gdb/testsuite/gdb.trace/ftrace-lock.exp
> @@ -64,7 +64,7 @@ if ![runto_main] {
> return -1
> }
>
> -if { [gdb_test "info sharedlibrary" ".*${libipa}.*" "IPA loaded"] != 0 } {
> +if { [gdb_test "info sharedlibrary" ".*[file tail ${libipa}].*" "IPA loaded"] != 0 } {
> untested "Could not find IPA lib loaded"
> return 1
> }
> diff --git a/gdb/testsuite/gdb.trace/ftrace.exp b/gdb/testsuite/gdb.trace/ftrace.exp
> index 15ad7e7..ce6ac27 100644
> --- a/gdb/testsuite/gdb.trace/ftrace.exp
> +++ b/gdb/testsuite/gdb.trace/ftrace.exp
> @@ -217,7 +217,7 @@ proc test_ftrace_condition { condexp var list } \
>
> gdb_reinitialize_dir $srcdir/$subdir
>
> -if { [gdb_test "info sharedlibrary" ".*${libipa}.*" "IPA loaded"] != 0 } {
> +if { [gdb_test "info sharedlibrary" ".*[file tail ${libipa}].*" "IPA loaded"] != 0 } {
> untested "Could not find IPA lib loaded"
> return 1
> }
> diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
> index 1fb05c4..d6a9ead 100644
> --- a/gdb/testsuite/lib/gdb.exp
> +++ b/gdb/testsuite/lib/gdb.exp
> @@ -3374,7 +3374,7 @@ proc gdb_compile {source dest type options} {
> # dynamically load one by basename, we must specify rpath. If we
> # are using a remote host, DejaGNU will link to the shared library
> # using a relative path, so again we must specify an rpath.
> - if { $shlib_load || ($shlib_found && [is_remote target]) } {
> + if { $shlib_load || $shlib_found } {
> if { ([istarget "*-*-mingw*"]
> || [istarget *-*-cygwin*]
> || [istarget *-*-pe*]) } {
> @@ -3585,7 +3585,7 @@ proc gdb_compile_shlib {sources dest options} {
> set name ${dest}
> }
> lappend link_options "additional_flags=-Wl,--out-implib,${name}.a"
> - } elseif [is_remote target] {
> + } else {
> # By default, we do not set the soname. This causes the linker
> # on ELF systems to create a DT_NEEDED entry in the executable
> # refering to the full path name of the library. This is a
> @@ -4218,14 +4218,27 @@ proc gdb_download { filename } {
> # Copy the listed libraries to the target.
>
> proc gdb_load_shlibs { args } {
> - if {![is_remote target]} {
> - return
> - }
> + if {[is_remote target]} {
> + foreach file $args {
> + # When the target is remote, we simply send the file to the target.
> + gdb_download [shlib_target_file $file]
> + }
> + } else {
> + foreach from $args {
> + # When the target is native, we copy the files to the test directory
> + # (next to the executable), except if that's already where it is.
> + set to [standard_output_file [file tail $from]]
>
> - foreach file $args {
> - gdb_download [shlib_target_file $file]
> + set from [file normalize $from]
> + set to [file normalize $to]
> +
> + if {"$from" != "$to"} {
> + file copy -force $from $to
> + }
> + }
> }
>
> +
> # Even if the target supplies full paths for shared libraries,
> # they may not be paths for this system.
> gdb_test "set solib-search-path [file dirname [lindex $args 0]]" "" ""
>
Ping.