Question

这是一个简单的Rust示例，其中包含我在GDB中运行的Vec和HashMap：

use std::collections::HashMap;

fn main() {
    let v = vec!["Mon", "Tue", "Wed"];
    println!("{:?}", v);

    let mut h = HashMap::new();
    h.insert(1,"Jan");
    h.insert(2,"Feb");
    h.insert(3,"Mar");
    h.insert(4,"Apr");
    println!("{:?}", h);
}

当我查看Vec它是漂亮的，而HashMap则不是：

bash$ rust-gdb target/debug/test_hashmap
GNU gdb (GDB) 8.1
Copyright (C) 2018 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-pc-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from target/debug/test_hashmap...done.
(gdb) b 12
Breakpoint 1 at 0xa056: file src/main.rs, line 12.
(gdb) r
Starting program: /home/john/proj/test_hashmap/target/debug/test_hashmap 
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/usr/lib/libthread_db.so.1".
["Mon", "Tue", "Wed"]

Breakpoint 1, test_hashmap::main () at src/main.rs:12
12          println!("{:?}", h);
(gdb) p v
$1 = Vec<&str>(len: 3, cap: 3) = {"Mon", "Tue", "Wed"}
(gdb) p h
$2 = HashMap<i32, &str, std::collections::hash::map::RandomState> = {hash_builder = RandomState = {k0 = 12919411587537124140, 
    k1 = 836420561220520453}, table = RawTable<i32, &str> = {capacity_mask = 31, size = 4, hashes = TaggedHashUintPtr = {
      Unique<usize> = {pointer = NonZero<*const usize> = {0x7ffff6c1c400}, _marker = PhantomData<usize>}}, 
    marker = PhantomData<(i32, &str)>}, resize_policy = DefaultResizePolicy}
(gdb) info pretty-printer
global pretty-printers:
  builtin
    mpx_bound128
  objfile /home/john/proj/test_hashmap/target/debug/test_hashmap pretty-printers:
  rust_pretty_printer_lookup_function
(gdb) n
{1: "Jan", 4: "Apr", 3: "Mar", 2: "Feb"}
13      }
(gdb)

程序看到HashMap（并打印其值正常），但我无法在GDB中看到它们。似乎启用了Rust pretty打印机，因为打印出Vec就好了。

如何在常规GDB中获取HashMap键和值？

Answer 1

目前无法为HashMap打印漂亮的键值项目。

有an open issue requesting this feature。

Answer 2

如果this PR is merged，将启用BTreeMap的漂亮打印。

BTreeMap和HashMap API相似。因此，您可以替换HashMap和BTreeMap进行调试。

Answer 3

您可以使用 rust-gdb/rust-lldb，它可以漂亮地打印 HashMap 的键值项。

如何在GDB中打印Rust HashMap？

3 个答案: