Demos

A series of demos when learning and working with LLDB.

For the demos which includes a python script to print debug info requets from LLDB, type the following commands to set up the script.

defaults delete com.apple.DebugSymbols
defaults write com.apple.DebugSymbols DBGShellCommands <full-path-to-script.py>

simple

A simple example of how to compile a hello world program and how to use LLDB to debug it.

class

Set breakpoints by class and method names.

dylib

LLDB request dsyms for dylibs at target creation time.

pull_dsym

A shell script can be used to resolve UUIDs into dsym files when LLDB requests such dsym files.

Ref: https://lldb.llvm.org/use/symbols.html

load_at_breakpoint

LLDB does NOT request dsyms when a breakpoint is set, nor when a breakpoint is triggered.

inline_functions

• Inline functions are compiled into each binary's .debug_lines table.
• settings set target.inline-breakpoint-strategy <always|headers|never> to control whether or not to resolve inline functions for source and header files.

breakpoint_resolution_file_line

Logic to resolve file/line breakpoints:

• Iterate through all CU
  • Find matching CUs by looking at both:
    • The settings target.inline-breakpoint-strategy
    • The file list in the line table prologue
  • If a CU matches, load/look at its line table content to find the address
  • Load/look at its symbol table to find the function that contains the address

settings__preload_symbols

When the setting is off:

+--------+-----------------+--------------------+
| Module | Add Symbol File | Parse Symbol Table |
+--------+-----------------+--------------------+
| user   | at attach       | at br set          |
+--------+-----------------+--------------------+
| shared | at attach       | at attach          |
+--------+-----------------+--------------------+

Common Setup

Command line aliases

cccc='xcrun clang++ -g -O0 -std=gnu++11 -stdlib=libc++'
dddd=dwarfdump
ddddan='dwarfdump --apple-names'
dddddl='dwarfdump --debug-line'
hhhh='objdump --section-headers'
oooo='otool -lv'
ssss='dsymutil -s'