rust-lldb encounters an error displaying local variables

[zmitchell]

I've loaded a (test) binary into rust-lldb via:

$ rust-lldb target/debug/deps/<mylib>-<hash>

then I stepped through a few lines of code and tried to list the local variables in the current stack frame:

(lldb) fr v

and encountered this error:

Traceback (most recent call last):
  File "/nix/store/r7hh9v94avlha6yrgv5a1dfwgfvkcyhl-rustc-1.70.0/lib/rustlib/etc/lldb_providers.py", line 516, in get_child_at_index
    idx = self.valid_indices[index]
IndexError: list index out of range
Traceback (most recent call last):
  File "/nix/store/r7hh9v94avlha6yrgv5a1dfwgfvkcyhl-rustc-1.70.0/lib/rustlib/etc/lldb_providers.py", line 516, in get_child_at_index
    idx = self.valid_indices[index]
IndexError: list index out of range
Traceback (most recent call last):
  File "/nix/store/r7hh9v94avlha6yrgv5a1dfwgfvkcyhl-rustc-1.70.0/lib/rustlib/etc/lldb_providers.py", line 516, in get_child_at_index
    idx = self.valid_indices[index]
IndexError: list index out of range
Traceback (most recent call last):
  File "/nix/store/r7hh9v94avlha6yrgv5a1dfwgfvkcyhl-rustc-1.70.0/lib/rustlib/etc/lldb_providers.py", line 516, in get_child_at_index
    idx = self.valid_indices[index]
IndexError: list index out of range

it did display all of the local variables though.

I expect the debugger to show all of the local variables without encountering an error.

Meta

rustc --version --verbose:

rustc 1.70.0 (90c541806 2023-05-31) (built from a source tarball)
binary: rustc
commit-hash: 90c541806f23a127002de5b4038be731ba1458ca
commit-date: 2023-05-31
host: aarch64-apple-darwin
release: 1.70.0
LLVM version: 16.0.1

[saethlin]

Do you have a reproducer for this problem you can share?

[zmitchell]

I don’t, the code I was working on is proprietary unfortunately

[Nicceboy]

I have also an issue on displaying local variables on aarch64-apple, but I am not sure whether it is related to this or how I could extract more information . Maybe I should open separate issue?

Sometimes the following happens

• A specific breakpoint causes some previous breakpoints to be skipped.
• As a result, the memory is messed up. Displaying content of the some variables is not possible, and some variables shows invalid content.

[saethlin]

Unless you are also seeing the Python exceptions above, definitely open a new issue.

[kpreid]

Relabeling issues which don't have a runnable reproduction (as opposed to not having a minimized one) to the new label S-needs-repro.
@rustbot label +S-needs-repro -E-needs-mcve

[Enselic]

Triage: Without a way to reproduce, not much can be done. Feel free to reopen or file a new issue when there is a way for others to reproduce. Thanks!