| Summary: | Pretty-printing support for Rust generators | ||
|---|---|---|---|
| Product: | gdb | Reporter: | Tyler Mandry <tmandry> |
| Component: | rust | Assignee: | Not yet assigned to anyone <unassigned> |
| Status: | UNCONFIRMED --- | ||
| Severity: | normal | CC: | tromey |
| Priority: | P2 | ||
| Version: | unknown | ||
| Target Milestone: | --- | ||
| Host: | Target: | ||
| Build: | Last reconfirmed: | ||
Opened as https://github.com/rust-lang/rust/issues/62572 on the Rust project; if you feel it's more appropriate to track there then feel free to close this issue. It would be helpful to have a small Rust test program using generators. |
Support printing Rust generators in a way that looks more like enums. Generators are represented in Rust as variant layouts with some extra fields on the outer layout. These extra fields (which are upvars, captured from the environment of the generator closure) seem to cause printing to become less pretty. Today printing a Rust generator looks like this: $2 = generator_objects::main::generator {__0: 0x7fffffffd204, <<variant>>: {__state: 3, 0: generator_objects::main::generator::Unresumed, 1: generator_objects::main::generator::Returned, 2: generator_objects::main::generator::Panicked, 3: generator_objects::main::generator::Suspend0 {c: 6, d: 7}, 4: generator_objects::main::generator::Suspend1 {c: 6, d: 7}}} Note that we print the fields of every single variant, even though the discriminant is marked in DWARF. Here's the source code: https://github.com/rust-lang/rust/blob/c6a9e766f90a5271c2356fbc7941e38559200ab5/src/test/debuginfo/generator-objects.rs. The above excerpt is from the second print in the test. __0 in the output is the upvar for `a` from the environment (it should be called `a` instead of `__0`, but this is a problem in the Rust compiler). The corresponding DWARF: https://gist.github.com/tmandry/92e1368b51bea06d11da1e45218813db