Merge query cache and query state

[zetanumbers]

So basically we have query cache and query state separate "hash" tables. Cache tracks completed queries while state tracks unfinished queries. Thus we are required to a double check lookup while updating one of them like in try_execute_query and we do multiple hash table lookups while executing a query since cache/state entry might have moved due to rehashing. This PR merges query cache with query state and stores query cache entries in an arena for its stable memory location.

However my manually written slop code currently breaks query cycle detection, but I know how to fix it.

More details in #t-compiler/query-system > Merging query cache and query state

[zetanumbers]

And there're the benchmark results for 4 threads on my MacBook Pro M1 Pro:

Benchmark	Before	After
	Time	Time	%
🟣 regex:check	0.2070s	0.2031s	💚 -1.90%
🟣 regex:check:initial	0.2437s	0.2430s	-0.28%
🟣 regex:check:unchanged	0.1195s	0.1192s	-0.25%
🟣 syn:check	0.3599s	0.3546s	💚 -1.48%
🟣 syn:check:initial	0.4273s	0.4204s	💚 -1.63%
🟣 syn:check:unchanged	0.2503s	0.2473s	💚 -1.21%
🟣 clap:check	0.3343s	0.3274s	💚 -2.07%
🟣 clap:check:initial	0.3885s	0.3804s	💚 -2.10%
🟣 clap:check:unchanged	0.1589s	0.1582s	-0.46%
🟣 hyper:check	0.0757s	0.0731s	💚 -3.42%
🟣 hyper:check:initial	0.0913s	0.0882s	💚 -3.44%
🟣 hyper:check:unchanged	0.0545s	0.0548s	0.53%
Total	2.7109s	2.6694s	💚 -1.53%
Summary	1.0000s	0.9852s	💚 -1.48%

[zetanumbers]

Can't get the parallel frontend cycle errors quite right as cycle breaking code cannot find any. This seems to only happen on a second break_query_cycle call tho. So I think maybe I didn't account for that somehow when thinking about order of operations or smth.

[zetanumbers]

Ah, and single-threaded cycle recovery haven't yet been put back too.

[petrochenkov]

@bors try @rust-timer queue

[rust-bors]

☀️ Try build successful (CI)
Build commit: 0ac810c (0ac810c5d67b1974c32e84e3ae9a74710b55ad5c, parent: 3bf5c6d99bc8a0c0d5b2f69826ed4f6d256a0a21)

[rust-timer]

Finished benchmarking commit (0ac810c): comparison URL.

Overall result: ❌✅ regressions and improvements - please read:

Benchmarking means the PR may be perf-sensitive. It's automatically marked not fit for rolling up. Overriding is possible but disadvised: it risks changing compiler perf.

Next, please: If you can, justify the regressions found in this try perf run in writing along with @rustbot label: +perf-regression-triaged. If not, fix the regressions and do another perf run. Neutral or positive results will clear the label automatically.

@bors rollup=never
@rustbot label: -S-waiting-on-perf +perf-regression

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	2.1%	[0.2%, 21.6%]	237
Regressions ❌ (secondary)	3.9%	[0.2%, 23.4%]	280
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.6%	[-1.0%, -0.2%]	13
All ❌✅ (primary)	2.1%	[0.2%, 21.6%]	237

Max RSS (memory usage)

Results (primary 0.8%, secondary 2.5%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	3.0%	[1.0%, 6.2%]	9
Regressions ❌ (secondary)	4.1%	[0.8%, 10.0%]	33
Improvements ✅ (primary)	-1.8%	[-3.1%, -0.9%]	8
Improvements ✅ (secondary)	-5.0%	[-10.2%, -0.8%]	7
All ❌✅ (primary)	0.8%	[-3.1%, 6.2%]	17

Cycles

Results (primary 5.6%, secondary 5.9%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	5.6%	[2.0%, 32.1%]	123
Regressions ❌ (secondary)	5.9%	[1.8%, 23.9%]	179
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	5.6%	[2.0%, 32.1%]	123

Binary size

Results (primary 0.1%, secondary 0.1%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	0.1%	[0.0%, 0.1%]	74
Regressions ❌ (secondary)	0.1%	[0.0%, 0.1%]	25
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.1%	[0.0%, 0.1%]	74

Bootstrap: 513.065s -> 530.367s (3.37%)
Artifact size: 400.58 MiB -> 404.66 MiB (1.02%)

[rust-log-analyzer]

The job aarch64-gnu-llvm-21-2 failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

   Compiling rustc_data_structures v0.0.0 (/checkout/compiler/rustc_data_structures)
error[E0308]: mismatched types
   --> compiler/rustc_data_structures/src/vec_cache/tests.rs:44:30
    |
 44 |         assert!(cache.lookup(&key).is_none());
    |                       ------ ^^^^ expected `u32`, found `&u32`
    |                       |
    |                       arguments to this method are incorrect
    |
note: method defined here
   --> compiler/rustc_data_structures/src/vec_cache.rs:191:12
    |
191 |     pub fn lookup(&self, key: K) -> &CacheEntry<V> {
    |            ^^^^^^        ------
help: consider removing the borrow
    |
 44 -         assert!(cache.lookup(&key).is_none());
 44 +         assert!(cache.lookup(key).is_none());
    |

error[E0599]: no method named `is_none` found for reference `&CacheEntry<u32>` in the current scope
  --> compiler/rustc_data_structures/src/vec_cache/tests.rs:44:36
   |
44 |         assert!(cache.lookup(&key).is_none());
   |                                    ^^^^^^^ method not found in `&CacheEntry<u32>`

error[E0599]: no method named `complete` found for struct `vec_cache::VecCache<K, V, I>` in the current scope
   --> compiler/rustc_data_structures/src/vec_cache/tests.rs:51:11
    |
 51 |     cache.complete(0, 1, 2);
    |           ^^^^^^^^ method not found in `vec_cache::VecCache<u32, u32, u32>`
    |
   ::: compiler/rustc_data_structures/src/vec_cache.rs:138:1
    |
138 | pub struct VecCache<K: Idx, V, I> {
    | --------------------------------- method `complete` not found for this struct

error[E0308]: mismatched types
   --> compiler/rustc_data_structures/src/vec_cache/tests.rs:52:29
    |
 52 |     assert_eq!(cache.lookup(&0), Some((1, 2)));
    |                      ------ ^^ expected `u32`, found `&{integer}`
    |                      |
    |                      arguments to this method are incorrect
    |
note: method defined here
   --> compiler/rustc_data_structures/src/vec_cache.rs:191:12
    |
191 |     pub fn lookup(&self, key: K) -> &CacheEntry<V> {
    |            ^^^^^^        ------
help: consider removing the borrow
    |
 52 -     assert_eq!(cache.lookup(&0), Some((1, 2)));
 52 +     assert_eq!(cache.lookup(0), Some((1, 2)));
    |

error[E0369]: binary operation `==` cannot be applied to type `&CacheEntry<u32>`
  --> library/core/src/macros/mod.rs:46:32
   |
42 | macro_rules! assert_eq {
   | ---------------------- in this expansion of `assert_eq!`
...
46 |                 if !(*left_val == *right_val) {
   |                      --------- ^^ ---------- Option<({integer}, {integer})>
   |                      |
   |                      &CacheEntry<u32>
   |
  ::: compiler/rustc_data_structures/src/vec_cache/tests.rs:52:5
   |
52 |     assert_eq!(cache.lookup(&0), Some((1, 2)));
   |     ------------------------------------------ in this macro invocation

error[E0277]: `CacheEntry<u32>` doesn't implement `std::fmt::Debug`
  --> library/core/src/macros/mod.rs:51:61
   |
42 | macro_rules! assert_eq {
   | ---------------------- in this expansion of `assert_eq!`
...
51 |                     $crate::panicking::assert_failed(kind, &*left_val, &*right_val, $crate::option::Option::None);
   |                                                             ^^^^^^^^^ unsatisfied trait bound
   |
  ::: compiler/rustc_data_structures/src/vec_cache/tests.rs:52:5
   |
52 |     assert_eq!(cache.lookup(&0), Some((1, 2)));
   |     ------------------------------------------ in this macro invocation
   |
help: the trait `std::fmt::Debug` is not implemented for `CacheEntry<u32>`
  --> compiler/rustc_data_structures/src/cache_entry.rs:82:1
   |
82 | pub struct CacheEntry<V> {
   | ^^^^^^^^^^^^^^^^^^^^^^^^
   = note: add `#[derive(Debug)]` to `CacheEntry<u32>` or manually `impl std::fmt::Debug for CacheEntry<u32>`

error[E0599]: no method named `complete` found for struct `vec_cache::VecCache<K, V, I>` in the current scope
   --> compiler/rustc_data_structures/src/vec_cache/tests.rs:73:15
    |
 73 |         cache.complete(key, shift, key);
    |               ^^^^^^^^ method not found in `vec_cache::VecCache<u32, u8, u32>`
    |
   ::: compiler/rustc_data_structures/src/vec_cache.rs:138:1
    |
138 | pub struct VecCache<K: Idx, V, I> {
    | --------------------------------- method `complete` not found for this struct

error[E0308]: mismatched types
   --> compiler/rustc_data_structures/src/vec_cache/tests.rs:74:33
    |
 74 |         assert_eq!(cache.lookup(&key), Some((shift, key)));
    |                          ------ ^^^^ expected `u32`, found `&u32`
    |                          |
    |                          arguments to this method are incorrect
    |
note: method defined here
   --> compiler/rustc_data_structures/src/vec_cache.rs:191:12
    |
191 |     pub fn lookup(&self, key: K) -> &CacheEntry<V> {
    |            ^^^^^^        ------
help: consider removing the borrow
    |
 74 -         assert_eq!(cache.lookup(&key), Some((shift, key)));
 74 +         assert_eq!(cache.lookup(key), Some((shift, key)));
    |

error[E0369]: binary operation `==` cannot be applied to type `&CacheEntry<u8>`
  --> library/core/src/macros/mod.rs:46:32
   |
42 | macro_rules! assert_eq {
   | ---------------------- in this expansion of `assert_eq!`
...
46 |                 if !(*left_val == *right_val) {
   |                      --------- ^^ ---------- Option<({integer}, u32)>
   |                      |
   |                      &CacheEntry<u8>
   |
  ::: compiler/rustc_data_structures/src/vec_cache/tests.rs:74:9
   |
74 |         assert_eq!(cache.lookup(&key), Some((shift, key)));
   |         -------------------------------------------------- in this macro invocation

error[E0277]: `CacheEntry<u8>` doesn't implement `std::fmt::Debug`
  --> library/core/src/macros/mod.rs:51:61
   |
42 | macro_rules! assert_eq {
   | ---------------------- in this expansion of `assert_eq!`
...
51 |                     $crate::panicking::assert_failed(kind, &*left_val, &*right_val, $crate::option::Option::None);
   |                                                             ^^^^^^^^^ unsatisfied trait bound
   |
  ::: compiler/rustc_data_structures/src/vec_cache/tests.rs:74:9
   |
74 |         assert_eq!(cache.lookup(&key), Some((shift, key)));
   |         -------------------------------------------------- in this macro invocation
   |
help: the trait `std::fmt::Debug` is not implemented for `CacheEntry<u8>`
  --> compiler/rustc_data_structures/src/cache_entry.rs:82:1
   |
82 | pub struct CacheEntry<V> {
   | ^^^^^^^^^^^^^^^^^^^^^^^^
   = note: add `#[derive(Debug)]` to `CacheEntry<u8>` or manually `impl std::fmt::Debug for CacheEntry<u8>`

error[E0599]: no method named `complete` found for reference `&vec_cache::VecCache<u32, u32, u32>` in the current scope
  --> compiler/rustc_data_structures/src/vec_cache/tests.rs:85:23
   |
85 |                 cache.complete(idx, idx, idx);
   |                       ^^^^^^^^ method not found in `&vec_cache::VecCache<u32, u32, u32>`

error[E0308]: mismatched types
   --> compiler/rustc_data_structures/src/vec_cache/tests.rs:91:33
    |
 91 |         assert_eq!(cache.lookup(&idx), Some((idx, idx)));
    |                          ------ ^^^^ expected `u32`, found `&{integer}`
    |                          |
    |                          arguments to this method are incorrect
    |
note: method defined here
   --> compiler/rustc_data_structures/src/vec_cache.rs:191:12
    |
191 |     pub fn lookup(&self, key: K) -> &CacheEntry<V> {
    |            ^^^^^^        ------
help: consider removing the borrow
    |
 91 -         assert_eq!(cache.lookup(&idx), Some((idx, idx)));
 91 +         assert_eq!(cache.lookup(idx), Some((idx, idx)));
    |

error[E0369]: binary operation `==` cannot be applied to type `&CacheEntry<u32>`
  --> library/core/src/macros/mod.rs:46:32
   |
42 | macro_rules! assert_eq {
   | ---------------------- in this expansion of `assert_eq!`
...
46 |                 if !(*left_val == *right_val) {
   |                      --------- ^^ ---------- Option<({integer}, {integer})>
   |                      |
   |                      &CacheEntry<u32>
   |
  ::: compiler/rustc_data_structures/src/vec_cache/tests.rs:91:9
   |
91 |         assert_eq!(cache.lookup(&idx), Some((idx, idx)));
   |         ------------------------------------------------ in this macro invocation

error[E0277]: `CacheEntry<u32>` doesn't implement `std::fmt::Debug`
  --> library/core/src/macros/mod.rs:51:61
   |
42 | macro_rules! assert_eq {
   | ---------------------- in this expansion of `assert_eq!`
...
51 |                     $crate::panicking::assert_failed(kind, &*left_val, &*right_val, $crate::option::Option::None);
   |                                                             ^^^^^^^^^ unsatisfied trait bound
   |
  ::: compiler/rustc_data_structures/src/vec_cache/tests.rs:91:9
   |
91 |         assert_eq!(cache.lookup(&idx), Some((idx, idx)));
   |         ------------------------------------------------ in this macro invocation
   |
help: the trait `std::fmt::Debug` is not implemented for `CacheEntry<u32>`
  --> compiler/rustc_data_structures/src/cache_entry.rs:82:1
   |
82 | pub struct CacheEntry<V> {
   | ^^^^^^^^^^^^^^^^^^^^^^^^
   = note: add `#[derive(Debug)]` to `CacheEntry<u32>` or manually `impl std::fmt::Debug for CacheEntry<u32>`

Some errors have detailed explanations: E0277, E0308, E0369, E0599.
For more information about an error, try `rustc --explain E0277`.
[RUSTC-TIMING] rustc_data_structures test:true 3.621
error: could not compile `rustc_data_structures` (lib test) due to 14 previous errors

[rust-bors]

☔ The latest upstream changes (presumably #157149) made this pull request unmergeable. Please resolve the merge conflicts.