BTreeMap: fix gdb introspection of BTreeMap with ZST keys or values

src/etc/gdb_providers.py

@@ -207,30 +207,46 @@ def children(self):
  yield "borrow", self.borrow
 
 
-# Yield each key (and optionally value) from a BoxedNode.
-def children_of_node(boxed_node, height, want_values):
+# Yields children (in a provider's sense of the word) for a tree headed by a BoxedNode.
+# In particular, yields each key/value pair in the node and in any child nodes.
+def children_of_node(boxed_node, height):
  def cast_to_internal(node):
- internal_type_name = str(node.type.target()).replace("LeafNode", "InternalNode", 1)
+ internal_type_name = node.type.target().name.replace("LeafNode", "InternalNode", 1)
  internal_type = lookup_type(internal_type_name)
  return node.cast(internal_type.pointer())
 
  node_ptr = unwrap_unique_or_non_null(boxed_node["ptr"])
- node_ptr = cast_to_internal(node_ptr) if height > 0 else node_ptr
- leaf = node_ptr["data"] if height > 0 else node_ptr.dereference()
+ leaf = node_ptr.dereference()
  keys = leaf["keys"]
- values = leaf["vals"]
+ vals = leaf["vals"]
+ edges = cast_to_internal(node_ptr)["edges"] if height > 0 else None
  length = int(leaf["len"])
 
  for i in xrange(0, length + 1):
  if height > 0:
- child_ptr = node_ptr["edges"][i]["value"]["value"]
- for child in children_of_node(child_ptr, height - 1, want_values):
+ boxed_child_node = edges[i]["value"]["value"]
+ for child in children_of_node(boxed_child_node, height - 1):
  yield child
  if i < length:
- if want_values:
- yield keys[i]["value"]["value"], values[i]["value"]["value"]
- else:
- yield keys[i]["value"]["value"]
+ # Avoid "Cannot perform pointer math on incomplete type" on zero-sized arrays.
+ key = keys[i]["value"]["value"] if keys.type.sizeof > 0 else None
+ val = vals[i]["value"]["value"] if vals.type.sizeof > 0 else None
+ yield key, val
+
+
+# Yields children for a BTreeMap.
+def children_of_map(map):
+ if map["length"] > 0:
+ root = map["root"]
+ if root.type.name.startswith("core::option::Option<"):
+ root = root.cast(gdb.lookup_type(root.type.name[21:-1]))
+ boxed_root_node = root["node"]
+ height = root["height"]
+ for i, (key, val) in enumerate(children_of_node(boxed_root_node, height)):
+ if key is not None:
+ yield "key{}".format(i), key
+ if val is not None:
+ yield "val{}".format(i), val
 
 
 class StdBTreeSetProvider:
@@ -242,15 +258,8 @@ def to_string(self):
 
  def children(self):
  inner_map = self.valobj["map"]
- if inner_map["length"] > 0:
- root = inner_map["root"]
- if "core::option::Option<" in root.type.name:
- type_name = str(root.type.name).replace("core::option::Option<", "", 1)[:-1]
- root = root.cast(gdb.lookup_type(type_name))
-
- node_ptr = root["node"]
- for i, child in enumerate(children_of_node(node_ptr, root["height"], False)):
- yield "[{}]".format(i), child
+ for child in children_of_map(inner_map):
+ yield child
 
  @staticmethod
  def display_hint():
@@ -265,16 +274,8 @@ def to_string(self):
  return "BTreeMap(size={})".format(self.valobj["length"])
 
  def children(self):
- if self.valobj["length"] > 0:
- root = self.valobj["root"]
- if "core::option::Option<" in root.type.name:
- type_name = str(root.type.name).replace("core::option::Option<", "", 1)[:-1]
- root = root.cast(gdb.lookup_type(type_name))
-
- node_ptr = root["node"]
- for i, child in enumerate(children_of_node(node_ptr, root["height"], True)):
- yield "key{}".format(i), child[0]
- yield "val{}".format(i), child[1]
+ for child in children_of_map(self.valobj):
+ yield child
 
  @staticmethod
  def display_hint():

src/test/debuginfo/pretty-std-collections.rs

@@ -34,17 +34,20 @@
 // gdb-check:$6 = BTreeMap(size=15) = {[0] = pretty_std_collections::MyLeafNode (0), [...]}
 // (abbreviated because it's boring but we need enough elements to include internal nodes)
 
+// gdb-command: print zst_btree_map
+// gdb-check:$7 = BTreeMap(size=1)
+
 // gdb-command: print vec_deque
-// gdb-check:$7 = VecDeque(size=3) = {5, 3, 7}
+// gdb-check:$8 = VecDeque(size=3) = {5, 3, 7}
 
 // gdb-command: print vec_deque2
-// gdb-check:$8 = VecDeque(size=7) = {2, 3, 4, 5, 6, 7, 8}
+// gdb-check:$9 = VecDeque(size=7) = {2, 3, 4, 5, 6, 7, 8}
 
 // gdb-command: print hash_map
-// gdb-check:$9 = HashMap(size=4) = {[1] = 10, [2] = 20, [3] = 30, [4] = 40}
+// gdb-check:$10 = HashMap(size=4) = {[1] = 10, [2] = 20, [3] = 30, [4] = 40}
 
 // gdb-command: print hash_set
-// gdb-check:$10 = HashSet(size=4) = {1, 2, 3, 4}
+// gdb-check:$11 = HashSet(size=4) = {1, 2, 3, 4}
 
 // === LLDB TESTS ==================================================================================
 
@@ -69,9 +72,9 @@
 #![allow(unused_variables)]
 use std::collections::BTreeMap;
 use std::collections::BTreeSet;
-use std::collections::VecDeque;
 use std::collections::HashMap;
 use std::collections::HashSet;
+use std::collections::VecDeque;
 use std::hash::{BuildHasherDefault, Hasher};
 
 struct MyLeafNode(i32); // helps to ensure we don't blindly replace substring "LeafNode"
@@ -111,6 +114,9 @@ fn main() {
  nasty_btree_map.insert(i, MyLeafNode(i));
  }
 
+ let mut zst_btree_map: BTreeMap<(), ()> = BTreeMap::new();
+ zst_btree_map.insert((), ());
+
  // VecDeque
  let mut vec_deque = VecDeque::new();
  vec_deque.push_back(5);