Re: [PATCH] Make ftrace tests work with remote targets

[Simon Marchi <simon dot marchi at ericsson dot com>]

On 16-03-31 07:18 PM, Pedro Alves wrote:
> On 03/31/2016 09:24 PM, Simon Marchi wrote:
>> On 16-03-29 06:46 PM, Pedro Alves wrote:
>>> On 03/03/2016 09:22 PM, Simon Marchi wrote:
>>>> --- 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 || $shlib_found } {
>>>
>>> I think the comment above needs updating.
>>
>> What about:
>>
>>      # Because we link with libraries using their basename, we may need
>>      # (depending on the platform) to set a special rpath value, to allow
>>      # the executable to find the libraries it depends on.
> 
> That's great.
> 
>>
>>>>  	    lappend link_options "additional_flags=-Wl,--out-implib,${name}.a"
>>>> -	} elseif [is_remote target] {
>>>> +	} else {
>>>>  	    # By default, we do not set the soname.  This causes the linker
>>>
>>> Likewise.
>>
>> What about:
>>
>>              # Set the soname of the library.  This causes the linker on ELF
>>              # systems to create the DT_NEEDED entry in the executable referring
>>              # to the soname of the library, and not its absolute path.  This
>>              # (using the absolute path) would be problem when testing on a
>>              # remote target.
>>              #
>>              # In conjunction with setting the soname, we add the special
>>              # rpath=$ORIGIN value when building the executable, so that it's
>>              # able to find the library in its own directory.
> 
> Perfect.
> 
>>
>>
>>>>  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]]
>>>
>>> I'd think it better to make the gdb_download path work for native
>>> testing as well.  WDYT?  E.g., make shlib_target_file default to
>>> return the test directory path?
>>
>> If I understand correctly, gdb_download would take a local file path and take
>> care of transferring that file to the "runtime test directory", whether it's
>> local or remote.
> 
> Right.  I'm not sure whether it's the right level or not.
> 
>   If the target is local, it checks whether $src == $dest, and
>> copies the file if not.  Basically, the same as my implementation of
>> gdb_load_shlibs, just not limited to shlibs.
> 
> *nod*
> 
> Now that I grep for gdb_download, sounds like we'll need to
> change mi_load_shlibs similarly.  Not sure offhand why the jit*.so
> hits don't use gdb_load_shlibs instead or gdb_download 
> 
>>
>> I am not sure if "make shlib_target_file default to return the test directory path?"
>> would be ok.  I think it's meant to return the local file path to download to the
>> target.
> 
> You're right.  I added those for SymbianOS years ago, since that target 
> had a post link step to convert elf to pe/dll, and it'd be the latter that'd
> be copied to the target.  IIRC.
> 
> 
>>  So gdb_load_shlibs would then become:
>>
>> proc gdb_load_shlibs { args } {
>>     foreach file $args {
>>         gdb_download [shlib_target_file $file]
>>     }
>> }
>>
>> I just tested it quickly and it seems to work fine.  But I also noticed that there
>> might be some overlap in feature between gdb_download and gdb_remote_download, so
>> perhaps I can try to merge them, WDYT?
>>
> 
> Indeed.
> 
>>>> # 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]]" "" ""
>>>
>>> Can we skip this command on native testing?
>>>
>>> I'm worried that that command might paper over, or cause, issues with
>>> sysroot / dso path lookup.  Normal native debugging usage will not specify
>>> that command, so if we could avoid it, I'd prefer it, on grounds of
>>> testing what users normally use.  
>>
>> Makes sense.  I'll add that, with a comment explaining why.
>>
>> Thanks!
>>
> 
> Thank you!
> 

V2 posted here: https://sourceware.org/ml/gdb-patches/2016-04/msg00047.html