[llvm] [GitHub] Add Copilot review instructions for LLDB (PR #165783)

[Kristof Beyls via llvm-commits]

================
@@ -0,0 +1,76 @@
+---
+applyTo: lldb/**/*
+---
+
+When reviewing code, focus on:
+
+## Language, Libraries & Standards
+
+- Target C++17 and avoid vendor-specific extensions.
+- For Python scripts, follow PEP 8.
+- Prefer standard library or LLVM support libraries instead of reinventing data structures.
+
+## Comments & Documentation
+
+- Each source file should include the standard LLVM file header.
+- Header files must have proper header guards.
+- Non-trivial classes and public methods should have Doxygen documentation.
+- Use `//` or `///` comments normally; avoid block comments unless necessary.
+
+## Language & Compiler Issues
+
+- Write portable code; wrap non-portable code in interfaces.
+- Do not use RTTI or exceptions.
+- Prefer C++-style casts over C-style casts.
+- Avoid static constructors or global objects with heavy initialization.
+- Use `class` or `struct` consistently; `struct` only for all-public data.
+
+## Headers & Library Layering
+
+- Include order: module header → local/private headers → project headers → system headers.
+- Headers must compile standalone (include all dependencies).
+- Maintain proper library layering; avoid circular dependencies.
+- Include minimally; use forward declarations where possible.
+- Keep internal headers private to modules.
+- Use full namespace qualifiers for out-of-line definitions.
+
+## Control Flow & Structure
+
+- Prefer early exits over deep nesting.
+- Avoid `else` after `return`, `continue`, `break`, or `goto`.
+- Encapsulate loops that compute predicates into helper functions.
+
+## Naming
+
+- LLDB's code style differs from LLVM's coding style.
+- Variables are `snake_case`.
+- Functions and methods are `UpperCamelCase`.
+- Static, global and member variables have `s_`, `g_` and `m_` prefixes respectively.
+
+## General Guidelines
+
+- Use `assert` liberally; prefer `llvm_unreachable` for unreachable states.
+- Avoid `using namespace std;` in headers.
+- Ensure at least one out-of-line virtual method per class with virtuals.
----------------
kbeyls wrote:

s/virtuals./virtual methods./
(Not sure if that would be better. As a human, that reads better, but maybe the shorter form is better for copilot?)

https://github.com/llvm/llvm-project/pull/165783