Hi Kyle, Apologies for the delay, this fell off my radar! The reality is a bit more complicated to what was described in a previous email in this thread.
> When stepping from point 1 to point 2, the breakpoint on the post-await > funclet at point 2 has to be conditional on being on the async_context being > the same async_context the debugger was using at point 1, right? And then you > have to be able to determine what the "same async_context" is. There are two things to keep in mind here: A) When performing some kind of stepping operation, LLDB uses the notion of ThreadPlans to guide the stepping procedure. Each thread has a ThreadPlanStack, containing all the plans to guide the debugger on when to stop a thread. As the name implies, the ThreadPlanStack is a property of each Thread. B) In Swift, each await operation may cause the currently executing Task to suspend and yield the Thread to a different Task. The previous Task may later be resumed on a different Thread entirely. Taking these two together, LLDB has to move ThreadPlanStacks from one Thread to another in sync to how a Task is moved from one Thread to another. You can find the mechanics of this by looking for `Process::FindDetachedPlanExplainingStop`: https://github.com/swiftlang/llvm-project/blob/stable/20240723/lldb/source/Target/Process.cpp#L1380 > On Oct 9, 2024, at 07:40, Kyle Huey via Dwarf-discuss > <dwarf-discuss@lists.dwarfstd.org> wrote: > > Hi Felipe, > > Any chance you could point me in the right direction? > > - Kyle > > On Tue, Oct 1, 2024 at 9:41 AM Adrian Prantl <apra...@apple.com> wrote: >> >> CC'ing Felipe, who is currently reworking a lot of this code and is much >> deeper in the subject matter than me. >> >> -- adrian >> >>> On Oct 1, 2024, at 8:42 AM, Kyle Huey <kh...@pernos.co> wrote: >>> >>> On Wed, Feb 28, 2024 at 10:02 AM Adrian Prantl <apra...@apple.com> wrote: >>>> LLDB implements this in a custom stepping plan that creates a conditional >>>> breakpoint where two async contexts are compared: First, there's the >>>> active async context at the time of the step. Next, the active async >>>> context at the time the breakpoint is hit. If the two async contexts are >>>> equal, then the breakpoint is discarded and the step has completed. >>> >>> Out of curiosity where does this code actually live? >>> >>> - Kyle >> > -- > Dwarf-discuss mailing list > Dwarf-discuss@lists.dwarfstd.org > https://lists.dwarfstd.org/mailman/listinfo/dwarf-discuss
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