lldb.md

lldb

This likely covers all my questions

Example run

Launch lldb from shell, important note of the -- before argument list.

lldb /Users/eric.seals/dev/work/build/bin/ixguard_SWIFT510 -- -config auto-ixguard.yml -o ./output/KotlinMultiPlatform_obfuscated.ipa KotlinMultiPlatform.ipa -d ./output

Since in this example I knew IXGuard would crash, I could just r to get to the crash. Once there, up and down to explore the stack frames. bt for full backtrace. f to print frame.

Printing variable

Printed out a frame:

(lldb) f
frame #1: 0x000000010197f9e0 ixguard_SWIFT510`ixguard::transforms::extra::(anonymous namespace)::GetCheckFunctionArgs(functionToInstrument=0x000060000a654008, checkFnType=0x00000001249222e0, builder=0x000000016fdf76d0) at AutoConfInstrumentation.cpp:66:39
   63     // If the function returns a struct, the first argument is a pointer where the
   64     // returned value goes
   65     const auto startIdx =
-> 66       functionToInstrument.arg_begin()->hasStructRetAttr() ? 1 : 0;
   67
   68     assert(functionToInstrument.arg_size() >= startIdx + 2U &&
   69            "ObjC methods should have at least 2 arguments: self and selector");

We can examine the contents of startIdx with p

(lldb) p startIdx
(const int) 0

VSCode LLDB

It's easier to just debug in visual studio code since it's "v i s u a l". Need to install the the CodeLLDB extension. Here's an example for the above example run:

{
  "configurations":
  [
    {
      "name": "Debug IXGuard",
      "type": "lldb",
      "request": "launch",
      "program": "/Users/eric.seals/dev/work/build/bin/ixguard_SWIFT510",
      "args":
      [
        "-config",
        "/Users/eric.seals/dev/work/ios-ipa/KotlinMultiPlatform/auto-ixguard.yml",
        "-o",
        "/Users/eric.seals/dev/work/ios-ipa/KotlinMultiPlatform/output/KotlinMultiPlatform_obfuscated.ipa",
        "/Users/eric.seals/dev/work/ios-ipa/KotlinMultiPlatform/KotlinMultiPlatform.ipa",
        "-d",
        "/Users/eric.seals/dev/work/ios-ipa/KotlinMultiPlatform/output",
      ],
    }
  ]
}