[lldb] Don't swallow crashlog exceptions

[JDevlieghere]

Summary

crashlog.py catches every exception in order to format them. This results in both the exception name as well as the backtrace getting swallowed.

Here's an example of the current output:

error: python exception: in method 'SBTarget_ResolveLoadAddress', argument 2 of type 'lldb::addr_t'

Compare this to the output without the custom exception handling:

Traceback (most recent call last):
  File "/Users/jonas/llvm/build-ra/lib/python3.9/site-packages/lldb/macosx/crashlog.py", line 929, in __call__
    SymbolicateCrashLogs(debugger, shlex.split(command))
  File "/Users/jonas/llvm/build-ra/lib/python3.9/site-packages/lldb/macosx/crashlog.py", line 1239, in SymbolicateCrashLogs
    SymbolicateCrashLog(crash_log, options)
  File "/Users/jonas/llvm/build-ra/lib/python3.9/site-packages/lldb/macosx/crashlog.py", line 1006, in SymbolicateCrashLog
    thread.dump_symbolicated(crash_log, options)
  File "/Users/jonas/llvm/build-ra/lib/python3.9/site-packages/lldb/macosx/crashlog.py", line 124, in dump_symbolicated
    symbolicated_frame_addresses = crash_log.symbolicate(
  File "/Users/jonas/llvm/build-ra/lib/python3.9/site-packages/lldb/utils/symbolication.py", line 540, in symbolicate
    if symbolicated_address.symbolicate(verbose):
  File "/Users/jonas/llvm/build-ra/lib/python3.9/site-packages/lldb/utils/symbolication.py", line 98, in symbolicate
    sym_ctx = self.get_symbol_context()
  File "/Users/jonas/llvm/build-ra/lib/python3.9/site-packages/lldb/utils/symbolication.py", line 77, in get_symbol_context
    sb_addr = self.resolve_addr()
  File "/Users/jonas/llvm/build-ra/lib/python3.9/site-packages/lldb/utils/symbolication.py", line 69, in resolve_addr
    self.so_addr = self.target.ResolveLoadAddress(self.load_addr)
  File "/Users/jonas/llvm/build-ra/lib/python3.9/site-packages/lldb/__init__.py", line 10675, in ResolveLoadAddress
    return _lldb.SBTarget_ResolveLoadAddress(self, vm_addr)
OverflowError: in method 'SBTarget_ResolveLoadAddress', argument 2 of type 'lldb::addr_t'

This patch removes the custom exception handling and lets LLDB deal with it instead.

[mib]

lldb/examples/python/crashlog.py

1025–1027

What about printing the exception backtrace and exiting cleaning instead of crashing ?

[JDevlieghere]

lldb/examples/python/crashlog.py

1025–1027

What's the advantage?

• LLBB's embedded python interpreter is going to catch the exception and put the crash info in the command result object.
• When running directly under Python, the default exception handler is going to print the backtrace as well.

[mib]

lldb/examples/python/crashlog.py

1025–1027

Alright, LGTM then

lldb/examples/python/crashlog.py

else:
         result.PutCString("error: invalid target")
 
 
 class Symbolicate:
     def __init__(self, debugger, internal_dict):
         pass
 
     def __call__(self, debugger, command, exe_ctx, result):
-        try:
-            SymbolicateCrashLogs(debugger, shlex.split(command))
-        except Exception as e:
-            result.PutCString("error: python exception: %s" % e)
 
     def get_short_help(self):
         return "Symbolicate one or more darwin crash log files."
 
     def get_long_help(self):
         option_parser = CrashLogOptionParser()
         return option_parser.format_help()
 

 
 def load_crashlog_in_scripted_process(debugger, crash_log_file, options):
     result = lldb.SBCommandReturnObject()
 
     crashlog_path = os.path.expanduser(crash_log_file)
     if not os.path.exists(crashlog_path):
         result.PutCString("error: crashlog file %s does not exist" % crashlog_path)
 
-    try:
-        crashlog = CrashLogParser().parse(debugger, crashlog_path, False)
-    except Exception as e:
-        result.PutCString("error: python exception: %s" % e)
-        return
 
     if debugger.GetNumTargets() > 0:
         target = debugger.GetTargetAtIndex(0)
     else:
         target = crashlog.create_target()
     if not target:
         result.PutCString("error: couldn't create target")
         return