[lldb] [llvm] Stateful variable-location annotations in Disassembler::PrintInstructions() (follow-up to #147460) (PR #152887)

[Abdullah Mohammad Amin via llvm-commits]

================
@@ -376,6 +380,143 @@ void Disassembler::PrintInstructions(Debugger &debugger, const ArchSpec &arch,
     }
   }
 
+  // Add rich variable location annotations to the disassembly output.
+  //
+  // For each instruction, this block attempts to resolve in-scope variables
+  // and determine if the current PC falls within their
+  // DWARF location entry. If so, it prints a simplified annotation using the
+  // variable name and its resolved location (e.g., "var = reg; " ).
+  //
+  // Annotations are only included if the variable has a valid DWARF location
+  // entry, and the location string is non-empty after filtering. Decoding
+  // errors and DWARF opcodes are intentionally omitted to keep the output
+  // concise and user-friendly.
+  //
+  // The goal is to give users helpful live variable hints alongside the
+  // disassembled instruction stream, similar to how debug information
+  // enhances source-level debugging.
+
+  struct VarState {
+    std::string name;     // display name
+    std::string last_loc; // last printed location (empty means <undef>)
+    bool seen_this_inst = false;
+  };
+
+  // Track live variables across instructions (keyed by stable LLDB user_id_t)
+  std::unordered_map<lldb::user_id_t, VarState> live_vars;
----------------
UltimateForce21 wrote:

Thanks for the pointer, I was able to switch to using `llvm::SmallDenseMap<>` now.

https://github.com/llvm/llvm-project/pull/152887