[maglev] Add NodeBase::Print() for GDB

.. where we sometimes want to inspect Node contents. With this CL, for
a human-readable print in gdb:

 print node->Print()

Note: Since we use an adhoc-created graph labeller, the output can't
properly identify input nodes and instead prints them as 'unregistered
node'.

Bug: v8:7700
Change-Id: Icba458ac1a5c43a09b815e12582443aca4e19380
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3890914
Auto-Submit: Jakob Linke <jgruber@chromium.org>
Commit-Queue: Jakob Linke <jgruber@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#83151}

src/maglev/maglev-graph-labeller.h

@@ -37,7 +37,7 @@ class MaglevGraphLabeller {
     auto node_id_it = node_ids_.find(node);
 
     if (node_id_it == node_ids_.end()) {
-      os << "<invalid node " << node << ">";
+      os << "<unregistered node " << node << ">";
       return;
     }
 

src/maglev/maglev-ir.cc

@@ -345,6 +345,12 @@ void NodeBase::Print(std::ostream& os, MaglevGraphLabeller* graph_labeller,
   UNREACHABLE();
 }
 
+void NodeBase::Print() const {
+  MaglevGraphLabeller labeller;
+  Print(std::cout, &labeller);
+  std::cout << std::endl;
+}
+
 namespace {
 size_t GetInputLocationsArraySize(const MaglevCompilationUnit& compilation_unit,
                                   const CheckpointedInterpreterState& state) {

src/maglev/maglev-ir.h

@@ -871,6 +871,9 @@ class NodeBase : public ZoneObject {
   void Print(std::ostream& os, MaglevGraphLabeller*,
              bool skip_targets = false) const;
 
+  // For GDB: Print any Node with `print node->Print()`.
+  void Print() const;
+
   EagerDeoptInfo* eager_deopt_info() {
     DCHECK(properties().can_eager_deopt());
     DCHECK(!properties().can_lazy_deopt());