Debugger

vm/types.v

@@ -34,6 +34,30 @@ struct Handler {
 	sp int // stack pointer right after the handler record
 }
 
+// DbgMode says what the debugger should do after an interactive session ends.
+enum DbgMode {
+	run // keep going until the next breakpoint (or the end)
+	step // stop at the very next instruction
+	next // stop after the current line returns to this frame level
+	finish // stop when the current function returns
+}
+
+// DbgState is the interactive debugger's runtime state, checked once per
+// instruction while enabled.
+struct DbgState {
+mut:
+	enabled     bool
+	breakpoints []int // source lines to stop at (first instruction of the line)
+	mode        DbgMode
+	start_bp    int // frame base captured when next/finish began
+	last_line   int // line at the moment the session stopped
+}
+
+struct FnEntry {
+	idx   int
+	entry int
+}
+
 struct Vm {
 mut:
 	code       []u8
@@ -57,6 +81,14 @@ mut:
 	const_strs int            // strings[0..const_strs] are bytecode constants, never collected
 	last_heap  int            // heap size at the last GC check (allocation trigger)
 	build_root string         // directory of the .vrmm build module (build_root() builtin)
+	dbg        DbgState       // interactive debugger state (vr debug)
+	dbg_locals []obj.DbgLocal // local name -> slot per function (debugger)
+	profiling  bool           // instruction/call counting (vr run --profile)
+	prof_instr []u64          // instructions executed per function index
+	prof_calls []u64          // calls made per function index
+	fn_of_ip   []int          // code offset -> function index (for profiling)
+	max_ops    i64            // instruction budget; 0 = unlimited (fuzzing safety)
+	ops        i64            // instructions executed so far
 }
 
 fn bool_i64(b bool) i64 {