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I am trying to debug a library whose source I don't have, so I'm using LLDB disassembly a lot. I was wondering if there was a way to automatically run disassemble after every call to 'thread step-in.' Currently, when I do 'thread step-in,' LLDB executes the instruction, and then returns with a blank prompt. To see, where the EIP moved to, I need to type disassemble after every thread step-in, which is extremely distracting and annoying (also, LLDB doesn't seem to end expressions with ';' so putting multiple commands on one line doesn't work.)
More generally, I was wondering if there is a way to create an alias for multiple LLDB commands in succession: For example a single alias that could print the contents of %rdi, then disassemble 10 lines around EIP. (Yes, I could write python script for it, but I don't have that much time on my hand :-(
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In lldb you can set breakpoints by typing either break or b followed by information on where you want the program to pause. After the b command, you can put either: a function name (e.g., b my_subroutine ) a line number (e.g., b 12 )
You can also expand the regsiters by register class: I'd like to know how to resize the various windows. If you resize the terminal, the size of the stack view pane seems to remain fixed, so the symbol names always end up truncated.
The standard LLDB installation provides you with an extensive set of commands designed to be compatible with familiar GDB commands. In addition to using the standard configuration, you can easily customize LLDB to suit your needs. Both GDB and LLDB are of course excellent debuggers without doubt.
Yes, the correct way to do this is via the Python scripting interface. There was a deliberate decision to avoid gdb's approach of cramming enough flow-control and execution logic in the debugger's command language to make this possible (or rather -- to make it possible... poorly). Instead of that approach, there is a low barrier where you need to use Python to accomplish a task -- but the full power of the debugger is available through some pretty easy-to-use interfaces in Python. lldb leaves the scripting language to Python and concentrates on providing a clean and powerful API that is easy to use from Python.
But to address your goal here, why won't the stop-disassembly-count setting do what you need? In fact, it should already be doing what you want unless you've disabled disassembly display in your ~/.lldbinit file by changing the default setting of stop-disassembly-display.
(lldb) settings show stop-disassembly-count
stop-disassembly-count (int) = 4
(lldb) settings show stop-disassembly-display
stop-disassembly-display (enum) = no-source
(lldb)
lldb's default behavior is to show some kind of context when you are stepping through a program. If source code is available, it will show the source you're stepping through. If no source, it will show the assembly instructions that are about to be executed. There is a little bug when you have debug information (so the debugger knows file and line numbers) but the source code is unavailable (or at a different path) -- right now lldb will show you disassembly but that is not the correct behavior for this case. Users are still operating at a source level (using s and n to step, instead of si and ni for instruction-level stepping) and lldb should show no context in this instance, just displaying the source file name and line number.
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