Flush pending diagnostics on crash. #4337
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| PrettyStackTraceFunction flush_on_crash([&](llvm::raw_ostream& out) { | ||
| // When crashing, print pending diagnostics to the crash stream. | ||
| // TODO: Eventually we'll want to limit the count. | ||
| out << "Pending diagnostics\n"; |
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Should we skip printing this if diagnostic streaming is enabled? (And maybe if there are no diagnostics?)
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PrettyStackTrace requires a stack allocation. A unique_ptr sort of works, but only if you immediately allocate it (or never allocate it) so that [construction and] destruction order is still stack-like. I believe it's infeasible to skip printing here (without removing the PrettyStackTraceFunction altogether): you end up with a number and malformatted stack trace output. We can print something different, but we cannot choose to skip printing based on later state.
I've added a slightly different label if streaming is enabled. We could skip both printing and flushing for streamed errors (i.e., just don't allocate a PrettyStackTraceFunction in this case), but my leaning would be that it's potentially helpful and more consistent to flush in both modes.
This risks diagnsotic formatting crashing, but I think we more frequently see cases where it'd be interesting to know what diagnostics were being delayed as part of the default sorting.