在调试用GDB编译Rust 1.10的程序时，无法在main上设置断点 [英] Unable to set a breakpoint on main while debugging a program compiled with Rust 1.10 with GDB

问题描述

  fn main（）{
 println！（Hello {}，0）; 
} 
  

我已经试过用两种方式编译： cargo build 和 rustc -g -L src / main.rs

然后运行 gdb target / debug / rust-gdb-test （或 gdb main ），并尝试在 main 与 break main 。

（ break :: rust-gdb-test :: main 返回函数： ：
$ b

断开后（断点1，0x0000555555559610在main（） ））如果我尝试运行 list ，我会得到：



  1 dl-debug.c：没有这样的文件或目录。 
  

我运行Rust 1.10.0 （cfcb716cf 2016-07-03） 和GDB 7.7.1 （Debian 7.7.1 + dfsg-5）。

两年前提出了一个类似的问题，但我无法在那里提出解决方案注意：我似乎没有安装GDB，只有LLDB，但对于这个问题，答案是同样的。

在Rust中看到的 main 不是一样的 main code>存在于编译后的二进制文件中。具体来说，两者之间有许多垫片方法。 Rust main 实际上包括箱子名称（在我的例子中是 buggin ）和一个散列（在我的例子中是<$ c
$ b

* frame＃0：0x000000010000126d $ c $ h code $ c> buggin`buggin :: main :: hfe08615ed561bb88 + 29 at main.rs:2
frame＃1：0x000000010000810e buggin`std :: panicking :: try :: call :: hbbf4746cba890ca7 + 30
frame＃2 ：0x000000010000aadc buggin`__rust_try + 12 $ b $ frame＃3：0x000000010000aa76 buggin`__rust_maybe_catch_panic + 38
frame＃4：0x0000000100007f32 buggin`std :: rt :: lang_start :: hbcefdc316c2fbd45 + 562
frame＃ 5：0x00000001000013aa buggin`main + 42
frame＃6：0x00007fff910435ad libdyld.dylib`start + 1 $ b $ frame＃7：0x00007fff910435ad libdyld.dylib`start + 1


在这里，您可以看到 main 在堆栈中几帧之外。

我倾向于使用通配符断点来处理散列：

 （lldb）br set -r'buggin :: main。*'
断点5： where = buggin`buggin :: main :: hfe08615ed561bb88 + 29，address = 0x000000010000126d 
  

rbreak 应该是GDB中的等价物。

程序停止后，您应该能够看到源代码。您也可能对Rust附带的 rust-lldb 和 rust-gdb 包装器感兴趣，并改善体验位。

这与这个答案基本相同，但是提到了散列。

既不是（gdb）rbreak'rust-gdb-test :: main。*' 也不是（lldb）br set -r'rust-gdb-test :: main。*'为我设置任何断点。

连字符（ - ）不是有效的符号字符。编译后，它被转换为下划线。

我原来的方法实际上是这样的：

 （lldb）br set -r'。* main。*'
断点2：67个位置。 
  

然后，您可以运行该程序并继续几次，直到找到正确的位置。不要害怕进入并探索一下;它只是一个调试器！

您可以尝试各种版本的正则表达式，以查看是否有任何有趣的匹配：

 （lldb）br set -r'。* main ::。*'
断点3：where = rust -gdb-test`rust_gdb_test： ：main :: h97d2ac6fea75a245 + 29，
（lldb）br set -r'。* :: main。*'
断点4：where = rust-gdb-test`rust_gdb_test :: main :: h97d2ac6fea75a245 + 29，
  

您也可以用一个非常独特的名称 main 并设置一个断点：

 （lldb）br set -r'。* a_really_unique_name。*'
  

I'm trying to step through this:

fn main() {
    println!("Hello {}", 0);
}

I've tried compiling with both: cargo build and rustc -g -L src/main.rs

I then run gdb target/debug/rust-gdb-test (or gdb main), and try to set a breakpoint on main with break main.

(break ::rust-gdb-test::main returns Function "::rust-gdb-test" not defined.).

After breaking (Breakpoint 1, 0x0000555555559610 in main ()) if I try to run list, I get:

1   dl-debug.c: No such file or directory.

I am running Rust 1.10.0 (cfcb716cf 2016-07-03) and GDB 7.7.1 (Debian 7.7.1+dfsg-5).

A similar question was asked 2 years ago, but I couldn't make the solutions presented there to work.

解决方案

Note: I seem to not have GDB installed anymore, only LLDB, but for this question the answer is the same.

The main that you see in Rust is not the same main that exists in the compiled binary. Specifically, there are a number of shim methods between the two. The Rust main actually includes the crate name (in my example buggin) and a hash (in my case hfe08615ed561bb88):

  * frame #0: 0x000000010000126d buggin`buggin::main::hfe08615ed561bb88 + 29 at main.rs:2
    frame #1: 0x000000010000810e buggin`std::panicking::try::call::hbbf4746cba890ca7 + 30
    frame #2: 0x000000010000aadc buggin`__rust_try + 12
    frame #3: 0x000000010000aa76 buggin`__rust_maybe_catch_panic + 38
    frame #4: 0x0000000100007f32 buggin`std::rt::lang_start::hbcefdc316c2fbd45 + 562
    frame #5: 0x00000001000013aa buggin`main + 42
    frame #6: 0x00007fff910435ad libdyld.dylib`start + 1
    frame #7: 0x00007fff910435ad libdyld.dylib`start + 1

Here, you can see that main is a few frames away in the stack.

I tend to use a wildcard breakpoint to not deal with the hash:

(lldb) br set -r 'buggin::main.*'
Breakpoint 5: where = buggin`buggin::main::hfe08615ed561bb88 + 29, address = 0x000000010000126d

rbreak should be an equivalent in GDB.

Once the program is stopped, you should be able to see the source. You may also be interested in the rust-lldb and rust-gdb wrappers that ship with Rust and improve the experience a bit.

This is basically the same as this answer, but mentions the hash.

Neither (gdb) rbreak 'rust-gdb-test::main.*' nor (lldb) br set -r 'rust-gdb-test::main.*' set any breakpoints for me.

The hyphen (-) is not a valid symbol character. When compiled, it is converted to an underscore.

My original methodology was actually this:

(lldb) br set -r '.*main.*'
Breakpoint 2: 67 locations.

You can then run the program and continue a few times until you find the right place. Don't be afraid to get in there and explore a bit; it's just a debugger!

You could try various versions of the regex to see if anything interesting might match:

(lldb) br set -r '.*main::.*'
Breakpoint 3: where = rust-gdb-test`rust_gdb_test::main::h97d2ac6fea75a245 + 29,
(lldb) br set -r '.*::main.*'
Breakpoint 4: where = rust-gdb-test`rust_gdb_test::main::h97d2ac6fea75a245 + 29,

You could also call a function with a very unique name from main and set a breakpoint on that:

(lldb) br set -r '.*a_really_unique_name.*'

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