labath added a comment.
The snippets you showed are pretty-much expected behavior. The backtrace that
gets printed as a part of the log messages is coming from the backtrace(3)
library, which has pretty limited backtracing capabilities -- it only looks at
the symbols in the `.dynsym` section (because that's the only thing that is
loaded into memory). I am pretty sure you would have problems backtracing if
you compiled with -fomit-frame-pointer as well.
I think you fix of just making sure that all symbols show up in the .dynsym
section would be fine, were it not for that fact that we have an inconsistent
linking policy, which means you get wildly different links depending on whether
you export something or not. If we get that straight that this would just be a
size optimization (that was the reason we introduced it), with no impact on the
behavior, that we could even consider turning off by default (I personally have
never used the -S option of logging, but I can see how it could be useful in
some workflows). I'll get back to the link policy in a separate email.
That said, you mentioned you also had some problems with setting breakpoints
and stuff. Now, if this was true, that would be extremely worrying, but am not
able to reproduce that on my side -- breakpoints everything else works fine.
The reason for that is that lldb reads the .symtab section (if it is present,
which it will be unless you strip the executable), and these linker options do
not affect that section. If that is not the case, then we definitely need to
figure that out (I suggest stepping through ObjectFileELF::GetSymtab() to get
an initial idea of what is going on).
FWIW, this is how a debug session looks like for me. The backtrace() output has
addresses only, but lldb is able to symbolicate it with no problem:
$ bin/lldb -- bin/lldb /bin/ls
(lldb) target create "bin/lldb"
Current executable set to 'bin/lldb' (x86_64).
(lldb) settings set -- target.run-args "/bin/ls"
(lldb) br set -n Log::VAPrintf
Breakpoint 1: no locations (pending).
WARNING: Unable to resolve breakpoint to any actual locations.
(lldb) pr la
Process 87438 launched: '/usr/local/google/home/labath/ll/build/dbg/bin/lldb'
(x86_64)
1 location added to breakpoint 1
Process 87438 stopped and restarted: thread 1 received signal: SIGCHLD
(lldb) target create "/bin/ls"
Current executable set to '/bin/ls' (x86_64).
(lldb) log enable -S lldb process
(lldb) pr la
Process 87438 stopped
* thread #1: tid = 87438, 0x00007ffff0d1cfeb
liblldb.so.40`lldb_private::Log::VAPrintf(this=0x000000000059a560,
format="ProcessLaunchInfo::%s at least one of stdin/stdout/stderr was not set,
evaluating default handling", args=0x00007fffffffc1a0) + 27 at Log.cpp:73, name
= 'lldb', stop reason = breakpoint 1.1
frame #0: 0x00007ffff0d1cfeb
liblldb.so.40`lldb_private::Log::VAPrintf(this=0x000000000059a560,
format="ProcessLaunchInfo::%s at least one of stdin/stdout/stderr was not set,
evaluating default handling", args=0x00007fffffffc1a0) + 27 at Log.cpp:73
70 void Log::VAPrintf(const char *format, va_list args) {
71 // Make a copy of our stream shared pointer in case someone
disables our
72 // log while we are logging and releases the stream
-> 73 StreamSP stream_sp(m_stream_sp);
74 if (stream_sp) {
75 static uint32_t g_sequence_id = 0;
76 StreamString header;
(lldb) c
Process 87438 resuming
ProcessLaunchInfo::FinalizeFileActions at least one of stdin/stdout/stderr
was not set, evaluating default handling
0 liblldb.so.40 0x00007ffff4d5a36f
1 liblldb.so.40 0x00007ffff0d1d49f
2 liblldb.so.40 0x00007ffff0d1cfbb
3 liblldb.so.40 0x00007ffff0fff4c4
4 liblldb.so.40 0x00007ffff103ad63
5 liblldb.so.40 0x00007ffff15c4f9f
6 liblldb.so.40 0x00007ffff0e33fe0
7 liblldb.so.40 0x00007ffff0e20317
8 liblldb.so.40 0x00007ffff0e25c0d
9 liblldb.so.40 0x00007ffff0e265a7
10 liblldb.so.40 0x00007ffff0cf5a60
11 liblldb.so.40 0x00007ffff0cb5c3c
12 liblldb.so.40 0x00007ffff0e26fdf
13 liblldb.so.40 0x00007ffff09d8d21
lldb::SBDebugger::RunCommandInterpreter(bool, bool) + 129
14 lldb 0x0000000000407c15
15 lldb 0x0000000000408257
16 libc.so.6 0x00007fffeeeb8f45 __libc_start_main + 245
17 lldb 0x00000000004038d9
Process 87438 stopped
* thread #1: tid = 87438, 0x00007ffff0d1cfeb
liblldb.so.40`lldb_private::Log::VAPrintf(this=0x000000000059a560,
format="ProcessLaunchInfo::%s target stdin='%s', target stdout='%s',
stderr='%s'", args=0x00007fffffffc1a0) + 27 at Log.cpp:73, name = 'lldb', stop
reason = breakpoint 1.1
frame #0: 0x00007ffff0d1cfeb
liblldb.so.40`lldb_private::Log::VAPrintf(this=0x000000000059a560,
format="ProcessLaunchInfo::%s target stdin='%s', target stdout='%s',
stderr='%s'", args=0x00007fffffffc1a0) + 27 at Log.cpp:73
70 void Log::VAPrintf(const char *format, va_list args) {
71 // Make a copy of our stream shared pointer in case someone
disables our
72 // log while we are logging and releases the stream
-> 73 StreamSP stream_sp(m_stream_sp);
74 if (stream_sp) {
75 static uint32_t g_sequence_id = 0;
76 StreamString header;
(lldb) bt
* thread #1: tid = 87438, 0x00007ffff0d1cfeb
liblldb.so.40`lldb_private::Log::VAPrintf(this=0x000000000059a560,
format="ProcessLaunchInfo::%s target stdin='%s', target stdout='%s',
stderr='%s'", args=0x00007fffffffc1a0) + 27 at Log.cpp:73, name = 'lldb', stop
reason = breakpoint 1.1
* frame #0: 0x00007ffff0d1cfeb
liblldb.so.40`lldb_private::Log::VAPrintf(this=0x000000000059a560,
format="ProcessLaunchInfo::%s target stdin='%s', target stdout='%s',
stderr='%s'", args=0x00007fffffffc1a0) + 27 at Log.cpp:73
frame #1: 0x00007ffff0d1cfbb
liblldb.so.40`lldb_private::Log::Printf(this=0x000000000059a560,
format="ProcessLaunchInfo::%s target stdin='%s', target stdout='%s',
stderr='%s'") + 347 at Log.cpp:61
frame #2: 0x00007ffff0fff970
liblldb.so.40`lldb_private::ProcessLaunchInfo::FinalizeFileActions(this=0x00000000004a0170,
target=0x000000000058bea0, default_to_use_pty=true) + 1376 at
ProcessLaunchInfo.cpp:260
frame #3: 0x00007ffff103ad63
liblldb.so.40`lldb_private::Target::Launch(this=0x000000000058bea0,
launch_info=0x00000000004a0170, stream=0x00007fffffffcaa8) + 1315 at
Target.cpp:2835
frame #4: 0x00007ffff15c4f9f
liblldb.so.40`CommandObjectProcessLaunch::DoExecute(this=0x00000000004a0030,
launch_args=0x00007fffffffcd68, result=0x00007fffffffd4d8) + 1647 at
CommandObjectProcess.cpp:233
frame #5: 0x00007ffff0e33fe0
liblldb.so.40`lldb_private::CommandObjectParsed::Execute(this=0x00000000004a0030,
args_string="", result=0x00007fffffffd4d8) + 1344 at CommandObject.cpp:1008
frame #6: 0x00007ffff0e20317
liblldb.so.40`lldb_private::CommandInterpreter::HandleCommand(this=0x0000000000482750,
command_line="pr la", lazy_add_to_history=eLazyBoolCalculate,
result=0x00007fffffffd4d8, override_context=0x0000000000000000,
repeat_on_empty_command=true, no_context_switching=false) + 3527 at
CommandInterpreter.cpp:1679
frame #7: 0x00007ffff0e25c0d
liblldb.so.40`lldb_private::CommandInterpreter::IOHandlerInputComplete(this=0x0000000000482750,
io_handler=0x0000000000583190, line="pr la") + 301 at
CommandInterpreter.cpp:2713
frame #8: 0x00007ffff0e265a7 liblldb.so.40`non-virtual thunk to
lldb_private::CommandInterpreter::IOHandlerInputComplete(this=0x0000000000482750,
io_handler=0x0000000000583190, line="pr la") + 55 at
CommandInterpreter.cpp:2689
frame #9: 0x00007ffff0cf5a60
liblldb.so.40`lldb_private::IOHandlerEditline::Run(this=0x0000000000583190) +
608 at IOHandler.cpp:552
frame #10: 0x00007ffff0cb5c3c
liblldb.so.40`lldb_private::Debugger::ExecuteIOHandlers(this=0x0000000000480e90)
+ 140 at Debugger.cpp:899
frame #11: 0x00007ffff0e26fdf
liblldb.so.40`lldb_private::CommandInterpreter::RunCommandInterpreter(this=0x0000000000482750,
auto_handle_events=true, spawn_thread=false, options=0x00007fffffffd7d8) + 223
at CommandInterpreter.cpp:2910
frame #12: 0x00007ffff09d8d21
liblldb.so.40`lldb::SBDebugger::RunCommandInterpreter(this=0x00007fffffffdb48,
auto_handle_events=true, spawn_thread=false) + 129 at SBDebugger.cpp:814
frame #13: 0x0000000000407c15
lldb`Driver::MainLoop(this=0x00007fffffffdb28) + 4341 at Driver.cpp:1156
frame #14: 0x0000000000408257 lldb`main(argc=2, argv=0x00007fffffffdd28)
+ 471 at Driver.cpp:1254
frame #15: 0x00007fffeeeb8f45 libc.so.6`__libc_start_main(main=(lldb`main
at Driver.cpp:1218), argc=2, argv=0x00007fffffffdd28, init=<unavailable>,
fini=<unavailable>, rtld_fini=<unavailable>, stack_end=0x00007fffffffdd18) +
245 at libc-start.c:287
frame #16: 0x00000000004038d9 lldb`_start + 41
Repository:
rL LLVM
https://reviews.llvm.org/D26093
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