Add a Debugging tutorial

docs/README.md

@@ -32,6 +32,7 @@ Install Crystal and get it running.
 Introductory courses for beginners and advanced learners.
 
 * [Basics](tutorials/basics/README.md)
+* [Debugging](tutorials/debugging/README.md)
 
   </div>
   <div class="card" markdown="1">

docs/SUMMARY.md

@@ -143,3 +143,6 @@
         * [Strings](tutorials/basics/40_strings.md)
         * [Control Flow](tutorials/basics/50_control_flow.md)
         * [Methods](tutorials/basics/60_methods.md)
+    * [Debugging](tutorials/debugging/README.md)
+        * [Debuggers](tutorials/debugging/10_debuggers.md)
+        * [Caveats](tutorials/debugging/20_caveats.md)

docs/tutorials/debugging/10_debuggers.md

@@ -0,0 +1,6 @@
+# Debuggers
+
+## Tools
+
+* [GDB](https://www.sourceware.org/gdb/)
+* [LLDB](https://lldb.llvm.org/)

docs/tutorials/debugging/20_caveats.md

@@ -0,0 +1,19 @@
+# Caveats
+
+## Segmentation Fault During GC Initialization
+
+It is generally safe to ignore `SIGSEGV` during startup of a Crystal program. This is intended behavior; see the [Debugging](https://hboehm.info/gc/debugging.html) documentation of Crystal's [GC library](https://hboehm.info/gc/).
+
+### Mitigation
+
+Automatically ignore this segmentation fault with breakpoints:
+
+<!-- TODO: GDB mitigation instructions -->
+
+#### LLDB
+
+
+```
+breakpoint set -n main -G true -o true -C 'process handle -s false -n false SIGSEGV SIGBUS'
+breakpoint set -n __crystal_main -G true -o true -C 'process handle -s true -n true SIGSEGV SIGBUS'
+```

docs/tutorials/debugging/README.md

@@ -0,0 +1,8 @@
+# Debugging
+
+This course targets experienced Crystal programmers and discusses common tools and methods to debug your Crystal code.
+
+Contents:
+
+* [Debuggers](10_debuggers.md) – Introduction to common debugging tools compatible with Crystal
+* [Caveats](20_caveats.md) – Gotchas and limitations when debugging Crystal code