Check in the native lldb unwinder.

Not yet enabled as the default unwinder but there are no known
backtrace problems with the code at this point.

Added 'log enable lldb unwind' to help diagnose backtrace problems;
this output needs a little refining but it's a good first step.

eh_frame information is currently read unconditionally - the code
is structured to allow this to be delayed until it's actually needed.
There is a performance hit when you have to parse the eh_frame
information for any largeish executable/library so it's necessary
to avoid if possible.

It's confusing having both the UnwindPlan::RegisterLocation struct
and the RegisterConextLLDB::RegisterLocation struct, I need to rename
one of them.

The writing of registers isn't done in the RegisterConextLLDB subclass
yet; neither is the running of complex DWARF expressions from eh_frame
(e.g. used for _sigtramp on Mac OS X).

llvm-svn: 117256

1 files changed, 2 insertions, 0 deletions

diff --git a/lldb/source/lldb-log.cpp b/lldb/source/lldb-log.cpp
index 4e291fab4ab..ce8d2132c8b 100644
--- a/lldb/source/lldb-log.cpp
+++ b/lldb/source/lldb-log.cpp
@@ -152,6 +152,7 @@ lldb_private::EnableLog (StreamSP &log_stream_sp, uint32_t log_options, Args &ar
             else if (strcasestr(arg, "comm")   == arg)  flag_bits |= LIBLLDB_LOG_COMMUNICATION;
             else if (strcasestr(arg, "conn")   == arg)  flag_bits |= LIBLLDB_LOG_CONNECTION;
             else if (strcasestr(arg, "host")   == arg)  flag_bits |= LIBLLDB_LOG_HOST;
+            else if (strcasestr(arg, "unwind") == arg)  flag_bits |= LIBLLDB_LOG_UNWIND;
             else
             {
                 feedback_strm->Printf("error: unrecognized log category '%s'\n", arg);
@@ -186,6 +187,7 @@ lldb_private::ListLogCategories (Stream *strm)
         "\tshlib - log shared library related activities\n"
         "\tstate - log private and public process state changes\n"
         "\tstep - log step related activities\n"
+        "\tunwind - log stack unwind activities\n"
         "\tverbose - enable verbose loggging\n"
         "\twatch - log watchpoint related activities\n");
 }