[PATCH] D59811: [clangd] Add fallback mode for code completion when compile command or preamble is not ready.

Wed Apr 3 07:42:58 PDT 2019

sammccall added a comment.

Got here trying to understand how D60126 <https://reviews.llvm.org/D60126> works.

It seems there's two fairly independent changes here:

- the one described, allow actions to run without a preamble
- defer the blocking getCompileCommand() call until we're building the preamble

Certainly they interact to make zero-latency code completion work, but is it possible to pull the latter out of this patch?
There are other approaches to the second part (e.g. giving TUScheduler a reference to the global CDB) that might be cleaner. I don't think it needs to block D60126 <https://reviews.llvm.org/D60126>.

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Comment at: clangd/TUScheduler.h:204
+                       Callback<InputsAndPreamble> Action,
+                       bool AllowFallback = false);

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I think this isn't orthogonal to `PreambleConsistency`.
When would we use AllowFallback = true but PreambleConsistency = Consistent?

Two possible options:
 - adding a new `StaleOrAbsent` option to PreambleConsistency
 - changing `Stale` to these new semantics, as codeComplete is the only caller
The problem with the latter is we can't put it behind a flag.

Repository:
  rCTE Clang Tools Extra

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D59811/new/

https://reviews.llvm.org/D59811