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https://github.com/kwhrtsk/rust-lldb-workaround
rust-lldb on macOS, breakpoints does not work with tests in a lib target. This project shows workaround for the problem.
https://github.com/kwhrtsk/rust-lldb-workaround
Last synced: 3 months ago
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rust-lldb on macOS, breakpoints does not work with tests in a lib target. This project shows workaround for the problem.
- Host: GitHub
- URL: https://github.com/kwhrtsk/rust-lldb-workaround
- Owner: kwhrtsk
- Created: 2020-03-03T04:59:43.000Z (almost 5 years ago)
- Default Branch: master
- Last Pushed: 2020-03-06T12:15:18.000Z (almost 5 years ago)
- Last Synced: 2024-08-03T01:39:22.757Z (6 months ago)
- Language: Shell
- Homepage:
- Size: 9.77 KB
- Stars: 2
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
rust-lldb problem with unit tests in a lib target.
==================================================
**[UPDATE]**
This problem has already been fixed on master([rust-lang/cargo#7965][3]),
and will be released as [Cargo 1.43][4] at 2020-04-03.
## Problem description
On macOS, when I build tests in a lib target (with cargo test --lib --no-run),
and run LLDB on the test binary, breakpoints does not work.
This problem occurs with both `rust-lldb` and VSCode with [CodeLLDB][1].
## Environment
* **Operating system:** macOS Catalina 10.15.3
* **Rust toolchain:** stable-x86_64-apple-darwin
* **Rustc version:** 1.41.1 (f3e1a954d 2020-02-24)
* **lldb:** 9.0.1
* **VSCode:** 1.42.1
* **CodeLLDB:** 1.5.0
## Steps to reproduce
* `Cargo.toml`
```toml
[package]
name = "rust-lldb-workaround"
version = "0.1.0"
edition = "2018"
```
* `src/lib.rs`
```rust
#[cfg(test)]
mod tests {
#[test]
fn it_works() {
assert_eq!(2 + 2, 4);
}
}
```
* `test.sh` (script to reproduce)
```
#!/bin/bash
rm -rf target
bin=$(cargo test --lib --no-run --message-format=json | jq -r '.executable')
rust-lldb $bin <<- EOF
breakpoint set --name tests::it_works
EOF
```
```
Compiling rust-lldb-workaround v0.1.0 (/Users/kawahara_taisuke/.ghq/github.com/kwhrtsk/rust-lldb-workaround)
Finished test [unoptimized + debuginfo] target(s) in 0.51s
(lldb) command script import "/Users/kawahara_taisuke/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/etc/lldb_rust_formatters.py"
(lldb) type summary add --no-value --python-function lldb_rust_formatters.print_val -x ".*" --category Rust
(lldb) type category enable Rust
(lldb) target create "/Users/kawahara_taisuke/.ghq/github.com/kwhrtsk/rust-lldb-workaround/target/debug/rust_lldb_workaround-6e0ca18365abb7b9"
Current executable set to '/Users/kawahara_taisuke/.ghq/github.com/kwhrtsk/rust-lldb-workaround/target/debug/rust_lldb_workaround-6e0ca18365abb7b9' (x86_64).
(lldb) breakpoint set --name tests::it_works
Breakpoint 1: no locations (pending).
WARNING: Unable to resolve breakpoint to any actual locations.
```
## Why breakpoint does not work?
When build tests in a bin target, `cargo test` will create `.dSYM` in `target/debug/` directory.
```
% cargo test --bins --no-run --message-format=json 2> /dev/null | jq 'select(.target.kind | contains(["bin"])) | .filenames'
[
"/Users/kawahara_taisuke/.ghq/github.com/kwhrtsk/rust-lldb-workaround/target/debug/rust_lldb_workaround-4aae58342b9c3866",
"/Users/kawahara_taisuke/.ghq/github.com/kwhrtsk/rust-lldb-workaround/target/debug/rust_lldb_workaround-4aae58342b9c3866.dSYM"
]
% ls -l target/debug
total 1720
drwxr-xr-x 2 kawahara_taisuke staff 64 3 3 13:47 build
drwxr-xr-x 8 kawahara_taisuke staff 256 3 3 13:47 deps
drwxr-xr-x 2 kawahara_taisuke staff 64 3 3 13:47 examples
drwxr-xr-x 4 kawahara_taisuke staff 128 3 3 13:47 incremental
-rwxr-xr-x 2 kawahara_taisuke staff 874952 3 3 13:47 rust_lldb_workaround-4aae58342b9c3866
-rw-r--r-- 1 kawahara_taisuke staff 282 3 3 13:47 rust_lldb_workaround-4aae58342b9c3866.d
lrwxr-xr-x 1 kawahara_taisuke staff 47 3 3 13:47 rust_lldb_workaround-4aae58342b9c3866.dSYM -> deps/rust_lldb_workaround-4aae58342b9c3866.dSYM
```
But not when build tests in a lib target.
```
% cargo test --lib --no-run --message-format=json 2> /dev/null | jq 'select(.target.kind | contains(["lib"])) | .filenames'
[
"/Users/kawahara_taisuke/.ghq/github.com/kwhrtsk/rust-lldb-workaround/target/debug/rust_lldb_workaround-6e0ca18365abb7b9"
]
% ls -l target/debug
total 1720
drwxr-xr-x 2 kawahara_taisuke staff 64 3 3 13:49 build
drwxr-xr-x 5 kawahara_taisuke staff 160 3 3 13:49 deps
drwxr-xr-x 2 kawahara_taisuke staff 64 3 3 13:49 examples
drwxr-xr-x 3 kawahara_taisuke staff 96 3 3 13:49 incremental
-rwxr-xr-x 2 kawahara_taisuke staff 874968 3 3 13:49 rust_lldb_workaround-6e0ca18365abb7b9
-rw-r--r-- 1 kawahara_taisuke staff 201 3 3 13:49 rust_lldb_workaround-6e0ca18365abb7b9.d
% ls -l target/debug/deps
total 1720
-rwxr-xr-x 2 kawahara_taisuke staff 874968 3 3 13:49 rust_lldb_workaround-6e0ca18365abb7b9
-rw-r--r-- 1 kawahara_taisuke staff 290 3 3 13:49 rust_lldb_workaround-6e0ca18365abb7b9.d
drwxr-xr-x 3 kawahara_taisuke staff 96 3 3 13:49 rust_lldb_workaround-6e0ca18365abb7b9.dSYM
```
It seems to be intentional at the moment, and the binaries under `deps` directories are expected to run.
https://github.com/rust-lang/cargo/blob/e618d47a1765ca18d1601d4cf891a55a34d23aed/src/cargo/core/compiler/build_context/target_info.rs#L260-L269
But for tools like [CodeLLDB][1], it is desirable to create a `.dSYM` in `target/debug/` (at least at the moment).
In this document shows a simple workaround that just create `.dSYM` symlink in `target/debug/`.
Please let me know if you have any unexpected side effects.
## Workaround
Manually create a symlink to `.dSYM` between `cargo test` and `llvm`.
* test-workaround.sh
```
#!/bin/bash
rm -rf target
bin=$(cargo test --lib --no-run --message-format=json | jq -r '.executable')
# create symlink of .dSYM directory
(cd target/debug && for d in deps/*.dSYM; do ln -sf $d ./; done)
rust-lldb $bin <<- EOF
breakpoint set --name tests::it_works
EOF
```
```
Compiling rust-lldb-workaround v0.1.0 (/Users/kawahara_taisuke/.ghq/github.com/kwhrtsk/rust-lldb-workaround)
Finished test [unoptimized + debuginfo] target(s) in 0.53s
(lldb) command script import "/Users/kawahara_taisuke/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/etc/lldb_rust_formatters.py"
(lldb) type summary add --no-value --python-function lldb_rust_formatters.print_val -x ".*" --category Rust
(lldb) type category enable Rust
(lldb) target create "/Users/kawahara_taisuke/.ghq/github.com/kwhrtsk/rust-lldb-workaround/target/debug/rust_lldb_workaround-6e0ca18365abb7b9"
Current executable set to '/Users/kawahara_taisuke/.ghq/github.com/kwhrtsk/rust-lldb-workaround/target/debug/rust_lldb_workaround-6e0ca18365abb7b9' (x86_64).
(lldb) breakpoint set --name tests::it_works
Breakpoint 1: where = rust_lldb_workaround-6e0ca18365abb7b9`rust_lldb_workaround::tests::it_works::h666f078a6b384dfd + 18 at lib.rs:7:8, address = 0x0000000100000cd2
```
### VSCode
If you try to do the same with VSCode (and CodeLLDB), you get:
* `.vscode/launch.json`
```json
{
"version": "0.2.0",
"configurations": [
{
"type": "lldb",
"request": "launch",
"name": "Debug unit tests in library 'rust-lldb-workaround'",
"cargo": {
"args": [
"test",
"--no-run",
"--lib",
"--package=rust-lldb-workaround"
],
"filter": {
"name": "rust-lldb-workaround",
"kind": "lib"
}
},
"args": [],
"cwd": "${workspaceFolder}",
// Add this line.
"preLaunchTask": "symlink dSYM"
}
]
}
```
* `.vscode/tasks.json`
```json
{
"version": "2.0.0",
"tasks": [
{
"label": "symlink dSYM",
"type": "shell",
"command": "sh",
"args": [
"-c",
"cd ${workspaceFolder}/target/debug; for d in deps/*.dSYM; do ln -fs $d ./; done"
]
}
]
}
```
## References
* [rust-lang/rust#59907](https://github.com/rust-lang/rust/issues/59907)
* [rust-lang/cargo#7960](https://github.com/rust-lang/cargo/issues/7960)
If you are looking for Japanese translation, please see [this blog post][2].
[1]: https://github.com/vadimcn/vscode-lldb
[2]: https://chopschips.net/blog/2020/03/03/rust-lldb-workaround/
[3]: https://github.com/rust-lang/cargo/pull/7965
[4]: https://github.com/rust-lang/cargo/blob/master/CHANGELOG.md#cargo-143-2020-04-23