incr.comp.: Enable query result caching for many more queries

[michaelwoerister]

Newly cached queries are:

• const_is_rvalue_promotable_to_static
• trans_fulfill_obligation
• optimized_mir
• unsafety_check_result
• borrowck
• mir_borrowck
• mir_const_qualif
• contains_extern_indicator
• def_symbol_name
• symbol_name

This also includes the stricter Span hashing first mentioned in #46490, which will lead to more false positives in release builds but overall is more correct -- and necessary for caching MIR. Hopefully we will soon be able to reduce the rate of false positives again by factoring Span out of MIR.

r? @nikomatsakis

[nikomatsakis]

@bors r+

[bors]

📌 Commit a16f296 has been approved by nikomatsakis

[nikomatsakis]

@bors p=1 -- incremental is high priority

[bors]

⌛ Testing commit a16f296a55d0af8a5a1f12b097ff8623d7a9f186 with merge 24ee46af90b6e79c43b7c3c9aa4ecfc1f01e025b...

[bors]

💔 Test failed - status-travis

[kennytm]

Legit.

[00:07:50] error[E0277]: the trait bound `core::option::Option<mir::ClosureRegionRequirements>: serialize::Decodable` is not satisfied
[00:07:50]    --> /checkout/src/librustc/ty/maps/config.rs:634:48
[00:07:50]     |
[00:07:50] 634 |                 tcx.on_disk_query_result_cache.try_load_query_result(tcx, id)
[00:07:50]     |                                                ^^^^^^^^^^^^^^^^^^^^^ the trait `serialize::Decodable` is not implemented for `core::option::Option<mir::ClosureRegionRequirements>`
[00:07:50] ...
[00:07:50] 642 | impl_disk_cacheable_query!(mir_borrowck, |def_id| def_id.is_local());
[00:07:50]     | --------------------------------------------------------------------- in this macro invocation
[00:07:50]     |
[00:07:50]     = help: the following implementations were found:
[00:07:50]               <core::option::Option<T> as serialize::Decodable>
[00:07:50] 
[00:07:50] error[E0277]: the trait bound `core::option::Option<mir::ClosureRegionRequirements>: serialize::Encodable` is not satisfied
[00:07:50]    --> /checkout/src/librustc/ty/maps/on_disk_cache.rs:213:13
[00:07:50]     |
[00:07:50] 213 |             encode_query_results::<mir_borrowck, _>(tcx, enc, qri)?;
[00:07:50]     |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `serialize::Encodable` is not implemented for `core::option::Option<mir::ClosureRegionRequirements>`
[00:07:50]     |
[00:07:50]     = help: the following implementations were found:
[00:07:50]               <core::option::Option<T> as serialize::Encodable>
[00:07:50]     = note: required by `ty::maps::on_disk_cache::encode_query_results`
[00:07:50] 
[00:07:52] error: aborting due to 2 previous errors
[00:07:52] 
[00:07:52] error: Could not compile `rustc`.
[00:07:52] 

[michaelwoerister]

Rebased.

@bors r=nmatsakis

[bors]

📌 Commit 539e171 has been approved by nmatsakis

[bors]

⌛ Testing commit 539e171 with merge 88fc3bc...

[bors]

☀️ Test successful - status-appveyor, status-travis
Approved by: nmatsakis
Pushing 88fc3bc to master...