[PATCH] D51608: [modules] when deserializing method, ensure it has correct exception spec

[Steve O'Brien via Phabricator via cfe-commits]

elsteveogrande created this revision.
elsteveogrande added reviewers: rsmith, dblaikie.
Herald added a subscriber: cfe-commits.

(PR38627)

After deserializing, the `PendingExceptionSpecUpdates` table is iterated over to apply exception specs to functions.  There may be `EST_None`-type in this table.  However if there is a method in the redecl chain already having some other non-`EST_None` type, this should not be clobbered with none.

If we see `EST_None` avoid setting the exception spec.  (This is the default anyway, so it's safe to skip in the legit case.)

There may be *better* ways to actually fix this, rather than a simple 1-line defensive check like I did here.  It would be more complicated and quite outside my area of experience though.

Test Plan: Passes `ninja check-clang`, including a new test case.

Andrew Gallagher provided the test case (distilling it from a much more complex instance in our code base).


Repository:
  rC Clang

https://reviews.llvm.org/D51608

Files:
  lib/Serialization/ASTReader.cpp
  test/Modules/Inputs/PR38627/a.h
  test/Modules/Inputs/PR38627/module.modulemap
  test/Modules/pr38627.cpp

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