Add GDB support for ref wrapper

Author: Walnut356

src/etc/gdb_load_rust_pretty_printers.py

@@ -14,3 +14,8 @@
     gdb_lookup.register_printers(gdb.current_objfile())
 except Exception:
     gdb_lookup.register_printers(gdb.selected_inferior().progspace)
+
+try:
+    gdb_lookup.register_type_printers(gdb.current_objfile())
+except Exception:
+    gdb_lookup.register_type_printers(gdb.selected_inferior().progspace)

src/etc/gdb_lookup.py

@@ -16,6 +16,10 @@ def register_printers(objfile):
     objfile.pretty_printers.append(printer)
 
 
+def register_type_printers(objfile):
+    gdb.types.register_type_printer(objfile, PtrTypePrinter("PtrOrRef"))
+
+
 # BACKCOMPAT: rust 1.35
 def is_hashbrown_hashmap(hash_map):
     return len(hash_map.type.fields()) == 1

src/etc/gdb_providers.py

@@ -480,3 +480,68 @@ def children(self):
 
     def display_hint(self):
         return "map" if self._show_values else "array"
+
+
+class NestedRefProvider(printer_base):
+    def __init__(self, valobj):
+        self._valobj = valobj
+        self._ptr = self._valobj["ptr"]
+
+    def to_string(self):
+        return str(self._valobj.cast(self._ptr.type))
+
+    def children(self):
+        yield ("*ptr", self._ptr.referenced_value())
+
+    def num_children(self):
+        return 1
+
+    def display_hint(self):
+        return "array"
+
+
+PTR_CODES = (
+    gdb.TYPE_CODE_PTR,
+    gdb.TYPE_CODE_REF,
+    gdb.TYPE_CODE_RVALUE_REF,
+    gdb.TYPE_CODE_MEMBERPTR,
+)
+
+
+class PtrTypeRecognizer:
+    def recognize(self, type: gdb.Type) -> str:
+        if type.code not in PTR_CODES:
+            return None
+
+        name_parts = []
+
+        ptr_type: gdb.Type = type
+        ptee_type: gdb.Type = type.target()
+
+        while ptr_type.code in PTR_CODES:
+            is_ref: bool = ptr_type.code == gdb.TYPE_CODE_REF
+
+            if ptee_type.const() == ptee_type:
+                if is_ref:
+                    name_parts.append("&")
+                else:
+                    name_parts.append("*const ")
+            else:
+                if is_ref:
+                    name_parts.append("&mut ")
+                else:
+                    name_parts.append("*mut ")
+
+            ptr_type = ptee_type
+            try:
+                ptee_type = ptee_type.target()
+            except RuntimeError:
+                break
+
+        name_parts.append(ptr_type.unqualified().name)
+        return "".join(name_parts)
+
+
+class PtrTypePrinter(gdb.types.TypePrinter):
+    def instantiate(self):
+        return PtrTypeRecognizer()