This document provides an overview of LLDB, an open-source debugger developed by Apple. It discusses LLDB's architecture, how it uses Clang and is scriptable/pluggable. It also summarizes how LLDB sets breakpoints, evaluates expressions by running on the target process, and prints structured variables using Clang type representations. Testing for LLDB consists of around 20 test cases written in Python. There is opportunity for external contributors to help with areas like testing and improving the CLI.

1. Life of breakpoint or an introduction to LLDB internal 2010/07/25 MORITA Hajime

11. Architecture

16. LLDB representation of breakpoints

21. Evaluating expression: 2 Paths "void ___clang_expr(void *___clang_arg) {" + text + "}" @target @host

29. class TestClassTypes( lldbtest.TestBase ): ... def test_function_types(self): """Test 'callback' has function ptr type, then ...""" res = self.res exe = os.path.join(os.getcwd(), "a.out") self. ci.HandleCommand ( "file " + exe , res) self.assertTrue( res.Succeeded() ) # Break inside the main. self. ci.HandleCommand ( "breakpoint set -f main.c -l 21" , res) self.assertTrue( res.Succeeded() ) self.assertTrue( res.GetOutput() .startswith( "Breakpoint created: 1: file ='main.c', line = 21, ..." )) self. ci.HandleCommand ( "run" , res) time.sleep(0.1) self.assertTrue( res.Succeeded() ) ... # The stop reason of the thread should be breakpoint. self. ci.HandleCommand ( "thread list" , res) print "thread list ->", res.GetOutput() self.assertTrue(res. Succeeded() ) self.assertTrue(res. GetOutput() .find( 'state is Stopped' ) > 0 and ...) ...

31. Questions?