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Auto merge of rust-lang#68098 - ssomers:btreemap_gdb_pretty_print, r=…
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…Mark-Simulacrum

Test gdb pretty printing more and fix overzealous type substitution

Adresses a problem concerning printing BTreeMap / BTreeSet data in gdb: when the key or value type name contains substring "LeafNode", and the map has multiple nodes (e.g. more than 11 elements), printing causes an exception. E.g.

```
rustc -g - <<EOF
    use std::collections::BTreeMap;

    struct MyLeafNode(i8);

    fn main() {
        let m: BTreeMap<i8, MyLeafNode> = (0..12).map(|i| (i, MyLeafNode(i))).collect();
        assert!(!m.is_empty());
    }
EOF
```

```
$ rust-gdb rust_out
(gdb) b 7
(gdb) r
(gdb) p m
$1 = BTreeMap<i8, rust_out::MyLeafNode>(len: 12)Python Exception <class 'gdb.error'> No type named alloc::collections::btree::node::InternalNode<i8, rust_out::MyInternalNode>.:
use std::collections::BTreeMap;
```

The code was written in rust-lang#56144 by @tromey (and later touched upon by @RalfJung in rust-lang#57045, but I think that had nothing to do with the issues in this PR).
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bors committed Mar 22, 2020
2 parents 5574b1d + d8a136f commit 94d43d6
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Showing 2 changed files with 11 additions and 3 deletions.
2 changes: 1 addition & 1 deletion src/etc/gdb_rust_pretty_printing.py
Original file line number Diff line number Diff line change
Expand Up @@ -335,7 +335,7 @@ def children(self):
def children_of_node(boxed_node, height, want_values):
node_ptr = boxed_node['ptr']['pointer']
if height > 0:
type_name = str(node_ptr.type.target()).replace('LeafNode', 'InternalNode')
type_name = str(node_ptr.type.target()).replace('LeafNode', 'InternalNode', 1)
node_type = gdb.lookup_type(type_name)
node_ptr = node_ptr.cast(node_type.pointer())
leaf = node_ptr['data']
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12 changes: 10 additions & 2 deletions src/test/debuginfo/pretty-std-collections.rs
Original file line number Diff line number Diff line change
Expand Up @@ -26,17 +26,22 @@
// gdb-command: print empty_btree_map
// gdb-check:$4 = BTreeMap<i32, u32>(len: 0)

// gdb-command: print nasty_btree_map
// gdb-check:$5 = BTreeMap<i32, pretty_std_collections::MyLeafNode>(len: 1) = {[1] = pretty_std_collections::MyLeafNode (11)}

// gdb-command: print vec_deque
// gdb-check:$5 = VecDeque<i32>(len: 3, cap: 8) = {5, 3, 7}
// gdb-check:$6 = VecDeque<i32>(len: 3, cap: 8) = {5, 3, 7}

// gdb-command: print vec_deque2
// gdb-check:$6 = VecDeque<i32>(len: 7, cap: 8) = {2, 3, 4, 5, 6, 7, 8}
// gdb-check:$7 = VecDeque<i32>(len: 7, cap: 8) = {2, 3, 4, 5, 6, 7, 8}

#![allow(unused_variables)]
use std::collections::BTreeMap;
use std::collections::BTreeSet;
use std::collections::VecDeque;

struct MyLeafNode(i32); // helps to ensure we don't blindly replace substring "LeafNode"

fn main() {
// BTreeSet
let mut btree_set = BTreeSet::new();
Expand All @@ -54,6 +59,9 @@ fn main() {

let mut empty_btree_map: BTreeMap<i32, u32> = BTreeMap::new();

let mut nasty_btree_map: BTreeMap<i32, MyLeafNode> = BTreeMap::new();
nasty_btree_map.insert(1, MyLeafNode(11));

// VecDeque
let mut vec_deque = VecDeque::new();
vec_deque.push_back(5);
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