tree 6c2cb81cd157d520aa1bfea53b01acde6e3a634b
parent fc4eb86019022d6517fe131477ffe0b5917a6d8c
author Daniel Dunbar <daniel_dunbar@apple.com> 1494533171 -0700
committer Daniel Dunbar <daniel_dunbar@apple.com> 1494539254 -0700

Change DB API to find constant key IDs.

 - This changes the BuildEngine <-> DB interaction to rely on first getting a
   unique (interned, effectively) ID for all keys.

 - That change allows us to then change the BuildEngine-level result to store
   dependencies in terms of key IDs, instead of expanded rules. This results in
   dramatically reduced memory usage, but also since this matches the underlying
   database schema it allows for much more efficient loading of the result
   dependencies.

 - In particular, this eliminates several joins from the database
   implementation.

 - There is potentially more we could do here to eliminate the ancillary key
   table entirely and simply make the results themselves serve as the canonical
   identifier for a rule, but that requires a little more work.

 - This is good for a 35% speedup on null builds of large build graphs.

 - <rdar://problem/32139612> Change RuleResult to store key IDs