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August 18, 2018 01:35
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This lldb script lets you selectively ignore Obj-C exceptions. See http://chen.do/blog/2013/09/30/selectively-ignoring-objective-c-exceptions-in-xcode/
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import lldb | |
import re | |
import shlex | |
# This script allows Xcode to selectively ignore Obj-C exceptions | |
# based on any selector on the NSException instance | |
def getRegister(target): | |
if target.triple.startswith('x86_64'): | |
return "rdi" | |
elif target.triple.startswith('i386'): | |
return "eax" | |
elif target.triple.startswith('arm64'): | |
return "x0" | |
else: | |
return "r0" | |
def callMethodOnException(frame, register, method): | |
return frame.EvaluateExpression("(NSString *)[(NSException *)${0} {1}]".format(register, method)).GetObjectDescription() | |
def filterException(debugger, user_input, result, unused): | |
target = debugger.GetSelectedTarget() | |
frame = target.GetProcess().GetSelectedThread().GetFrameAtIndex(0) | |
if frame.symbol.name != 'objc_exception_throw': | |
# We can't handle anything except objc_exception_throw | |
return None | |
filters = shlex.split(user_input) | |
register = getRegister(target) | |
for filter in filters: | |
method, regexp_str = filter.split(":", 1) | |
value = callMethodOnException(frame, register, method) | |
if value is None: | |
output = "Unable to grab exception from register {0} with method {1}; skipping...".format(register, method) | |
result.PutCString(output) | |
result.flush() | |
continue | |
regexp = re.compile(regexp_str) | |
if regexp.match(value): | |
output = "Skipping exception because exception's {0} ({1}) matches {2}".format(method, value, regexp_str) | |
result.PutCString(output) | |
result.flush() | |
# If we tell the debugger to continue before this script finishes, | |
# Xcode gets into a weird state where it won't refuse to quit LLDB, | |
# so we set async so the script terminates and hands control back to Xcode | |
debugger.SetAsync(True) | |
debugger.HandleCommand("continue") | |
return None | |
return None | |
def __lldb_init_module(debugger, unused): | |
debugger.HandleCommand('command script add --function ignore_specified_objc_exceptions.filterException ignore_specified_objc_exceptions') |
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