Cache results of isGenericObjectType and isGenericIndexType

[ahejlsberg]

With this PR we cache the results of isGenericObjectType and isGenericIndexType for unions and intersections. This improves total compile time of the repro in #36564 by about 6.5%.

[ahejlsberg]

@typescript-bot perf test this

[typescript-bot]

Heya @ahejlsberg, I've started to run the perf test suite on this PR at a0546fc. You can monitor the build here. It should now contribute to this PR's status checks.

Update: The results are in!

[typescript-bot]

@ahejlsberg
The results of the perf run you requested are in!

Here they are:

Comparison Report - master..36622

Metric	master	36622	Delta	Best	Worst
Angular - node (v10.16.3, x64)
Memory used	356,893k (± 0.02%)	358,562k (± 0.02%)	+1,669k (+ 0.47%)	358,382k	358,699k
Parse Time	1.61s (± 0.52%)	1.62s (± 0.63%)	+0.01s (+ 0.50%)	1.60s	1.65s
Bind Time	0.89s (± 1.06%)	0.88s (± 0.92%)	-0.01s (- 0.79%)	0.86s	0.90s
Check Time	4.67s (± 0.67%)	4.65s (± 0.60%)	-0.02s (- 0.43%)	4.60s	4.72s
Emit Time	5.21s (± 0.63%)	5.20s (± 0.75%)	-0.01s (- 0.23%)	5.12s	5.30s
Total Time	12.38s (± 0.49%)	12.35s (± 0.48%)	-0.03s (- 0.22%)	12.23s	12.50s
Monaco - node (v10.16.3, x64)
Memory used	364,574k (± 0.02%)	364,633k (± 0.01%)	+60k (+ 0.02%)	364,537k	364,767k
Parse Time	1.24s (± 0.81%)	1.25s (± 0.52%)	+0.00s (+ 0.32%)	1.24s	1.27s
Bind Time	0.77s (± 0.29%)	0.77s (± 0.44%)	+0.00s (+ 0.26%)	0.77s	0.78s
Check Time	4.69s (± 0.62%)	4.68s (± 0.38%)	-0.00s (- 0.04%)	4.66s	4.74s
Emit Time	2.90s (± 0.98%)	2.89s (± 0.52%)	-0.01s (- 0.45%)	2.85s	2.92s
Total Time	9.61s (± 0.53%)	9.60s (± 0.32%)	-0.01s (- 0.09%)	9.55s	9.68s
TFS - node (v10.16.3, x64)
Memory used	324,176k (± 0.02%)	324,221k (± 0.08%)	+45k (+ 0.01%)	323,972k	325,262k
Parse Time	0.94s (± 0.59%)	0.94s (± 0.53%)	+0.00s (+ 0.32%)	0.94s	0.96s
Bind Time	0.75s (± 0.80%)	0.74s (± 1.38%)	-0.01s (- 0.67%)	0.71s	0.75s
Check Time	4.21s (± 0.48%)	4.22s (± 0.48%)	+0.01s (+ 0.21%)	4.18s	4.27s
Emit Time	3.01s (± 0.87%)	3.01s (± 1.26%)	+0.00s (+ 0.03%)	2.92s	3.08s
Total Time	8.90s (± 0.41%)	8.91s (± 0.39%)	+0.01s (+ 0.10%)	8.81s	8.98s
Angular - node (v12.1.0, x64)
Memory used	332,682k (± 0.02%)	334,173k (± 0.08%)	+1,491k (+ 0.45%)	333,192k	334,390k
Parse Time	1.55s (± 0.44%)	1.57s (± 0.82%)	+0.01s (+ 0.84%)	1.55s	1.60s
Bind Time	0.87s (± 1.07%)	0.87s (± 0.42%)	+0.01s (+ 0.69%)	0.87s	0.88s
Check Time	4.59s (± 0.49%)	4.59s (± 0.68%)	-0.00s (- 0.04%)	4.52s	4.68s
Emit Time	5.40s (± 0.79%)	5.43s (± 1.24%)	+0.03s (+ 0.57%)	5.29s	5.62s
Total Time	12.41s (± 0.51%)	12.45s (± 0.77%)	+0.05s (+ 0.37%)	12.26s	12.76s
Monaco - node (v12.1.0, x64)
Memory used	344,511k (± 0.01%)	344,539k (± 0.02%)	+28k (+ 0.01%)	344,408k	344,696k
Parse Time	1.21s (± 0.73%)	1.21s (± 0.70%)	-0.00s (- 0.25%)	1.19s	1.23s
Bind Time	0.75s (± 0.86%)	0.75s (± 0.87%)	-0.00s (- 0.53%)	0.74s	0.76s
Check Time	4.56s (± 0.61%)	4.53s (± 0.30%)	-0.03s (- 0.64%)	4.50s	4.56s
Emit Time	2.97s (± 0.65%)	2.96s (± 0.87%)	-0.01s (- 0.27%)	2.90s	3.03s
Total Time	9.49s (± 0.46%)	9.45s (± 0.23%)	-0.05s (- 0.48%)	9.40s	9.49s
TFS - node (v12.1.0, x64)
Memory used	306,390k (± 0.03%)	306,393k (± 0.01%)	+3k (+ 0.00%)	306,322k	306,490k
Parse Time	0.94s (± 0.71%)	0.93s (± 0.43%)	-0.01s (- 0.64%)	0.92s	0.94s
Bind Time	0.71s (± 0.71%)	0.70s (± 0.68%)	-0.00s (- 0.28%)	0.69s	0.71s
Check Time	4.18s (± 0.37%)	4.17s (± 0.49%)	-0.01s (- 0.22%)	4.13s	4.22s
Emit Time	3.07s (± 0.75%)	3.09s (± 0.87%)	+0.02s (+ 0.78%)	3.04s	3.17s
Total Time	8.88s (± 0.41%)	8.90s (± 0.39%)	+0.01s (+ 0.12%)	8.81s	8.97s
Angular - node (v8.9.0, x64)
Memory used	351,846k (± 0.01%)	353,479k (± 0.02%)	+1,633k (+ 0.46%)	353,290k	353,547k
Parse Time	2.10s (± 0.28%)	2.12s (± 0.39%)	+0.02s (+ 0.91%)	2.09s	2.13s
Bind Time	0.93s (± 1.10%)	0.94s (± 0.71%)	+0.01s (+ 0.64%)	0.92s	0.95s
Check Time	5.45s (± 0.65%)	5.45s (± 0.77%)	+0.00s (+ 0.07%)	5.36s	5.55s
Emit Time	6.24s (± 0.96%)	6.25s (± 1.30%)	+0.01s (+ 0.13%)	6.16s	6.48s
Total Time	14.71s (± 0.56%)	14.75s (± 0.64%)	+0.04s (+ 0.24%)	14.60s	15.05s
Monaco - node (v8.9.0, x64)
Memory used	362,868k (± 0.01%)	362,834k (± 0.01%)	-34k (- 0.01%)	362,783k	362,893k
Parse Time	1.56s (± 0.36%)	1.56s (± 0.49%)	-0.00s (- 0.19%)	1.54s	1.57s
Bind Time	0.95s (± 0.74%)	0.95s (± 0.52%)	-0.00s (- 0.32%)	0.94s	0.96s
Check Time	5.40s (± 1.36%)	5.40s (± 1.86%)	+0.01s (+ 0.13%)	5.25s	5.62s
Emit Time	3.32s (± 3.05%)	3.27s (± 4.67%)	-0.05s (- 1.54%)	2.96s	3.46s
Total Time	11.22s (± 0.41%)	11.18s (± 0.57%)	-0.05s (- 0.41%)	11.04s	11.32s
TFS - node (v8.9.0, x64)
Memory used	323,413k (± 0.01%)	323,432k (± 0.01%)	+20k (+ 0.01%)	323,353k	323,543k
Parse Time	1.26s (± 0.46%)	1.27s (± 0.61%)	+0.01s (+ 0.48%)	1.26s	1.29s
Bind Time	0.76s (± 0.45%)	0.76s (± 0.59%)	+0.00s (+ 0.13%)	0.75s	0.77s
Check Time	4.82s (± 0.66%)	4.82s (± 0.47%)	+0.00s (+ 0.00%)	4.77s	4.86s
Emit Time	3.19s (± 0.64%)	3.19s (± 0.94%)	+0.00s (+ 0.00%)	3.11s	3.27s
Total Time	10.04s (± 0.46%)	10.04s (± 0.36%)	+0.01s (+ 0.07%)	9.97s	10.14s
Angular - node (v8.9.0, x86)
Memory used	200,041k (± 0.03%)	200,900k (± 0.02%)	+859k (+ 0.43%)	200,804k	200,997k
Parse Time	2.02s (± 0.47%)	2.04s (± 0.41%)	+0.02s (+ 0.84%)	2.03s	2.07s
Bind Time	1.04s (± 0.77%)	1.05s (± 0.67%)	+0.01s (+ 0.86%)	1.03s	1.06s
Check Time	4.96s (± 0.85%)	4.92s (± 0.47%)	-0.03s (- 0.67%)	4.88s	4.97s
Emit Time	6.08s (± 1.90%)	6.07s (± 1.74%)	-0.01s (- 0.15%)	5.93s	6.32s
Total Time	14.11s (± 0.85%)	14.09s (± 0.69%)	-0.02s (- 0.14%)	13.95s	14.30s
Monaco - node (v8.9.0, x86)
Memory used	203,707k (± 0.02%)	203,727k (± 0.03%)	+20k (+ 0.01%)	203,627k	203,836k
Parse Time	1.60s (± 0.53%)	1.60s (± 0.56%)	-0.00s (- 0.25%)	1.58s	1.62s
Bind Time	0.77s (± 0.86%)	0.77s (± 0.64%)	-0.00s (- 0.52%)	0.76s	0.78s
Check Time	5.20s (± 1.80%)	5.10s (± 0.76%)	-0.10s (- 1.87%)	5.05s	5.23s
Emit Time	3.13s (± 2.71%)	3.20s (± 0.59%)	+0.07s (+ 2.20%)	3.17s	3.27s
Total Time	10.70s (± 0.50%)	10.66s (± 0.43%)	-0.03s (- 0.30%)	10.58s	10.80s
TFS - node (v8.9.0, x86)
Memory used	182,586k (± 0.01%)	182,558k (± 0.02%)	-28k (- 0.02%)	182,467k	182,655k
Parse Time	1.30s (± 0.76%)	1.30s (± 0.82%)	-0.01s (- 0.54%)	1.27s	1.33s
Bind Time	0.71s (± 1.19%)	0.71s (± 0.94%)	+0.00s (+ 0.14%)	0.70s	0.73s
Check Time	4.58s (± 1.09%)	4.57s (± 0.48%)	-0.01s (- 0.33%)	4.52s	4.62s
Emit Time	2.95s (± 0.74%)	2.96s (± 0.77%)	+0.01s (+ 0.20%)	2.92s	3.02s
Total Time	9.55s (± 0.72%)	9.53s (± 0.34%)	-0.02s (- 0.18%)	9.45s	9.59s

System

Machine Name	ts-ci-ubuntu
Platform	linux 4.4.0-166-generic
Architecture	x64
Available Memory	16 GB
Available Memory	4 GB
CPUs	4 × Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz

Hosts

• node (v10.16.3, x64)
• node (v12.1.0, x64)
• node (v8.9.0, x64)
• node (v8.9.0, x86)

Scenarios

• Angular - node (v10.16.3, x64)
• Angular - node (v12.1.0, x64)
• Angular - node (v8.9.0, x64)
• Angular - node (v8.9.0, x86)
• Monaco - node (v10.16.3, x64)
• Monaco - node (v12.1.0, x64)
• Monaco - node (v8.9.0, x64)
• Monaco - node (v8.9.0, x86)
• TFS - node (v10.16.3, x64)
• TFS - node (v12.1.0, x64)
• TFS - node (v8.9.0, x64)
• TFS - node (v8.9.0, x86)

Benchmark	Name	Iterations
Current	36622	10
Baseline	master	10

[amcasey]

@ahejlsberg How do these predicates relate to couldContainTypeVariables? Is there a reason these are ObjectFlags and that uses a property?

Context: instantiateType is frequently called on types that can't be instantiated and it seems like we could save some time (~2% on the material-ui benchmark above, in my naive implementation) by checking one or more of these cached values.

[ahejlsberg]

How do these predicates relate to couldContainTypeVariables? Is there a reason these are ObjectFlags and that uses a property?

The isGenericObjectType and isGenericIndexType functions are used to determine whether conditional types, indexed access types, and index types should be resolved, or whether resolution should be deferred in a higher-order type of the particular kind. It is possible for these functions to return false even if the given type references type variables, e.g. for the type { foo: T } where T is a type variable.

The couldContainTypeVariables function computes whether a type possibly contains type variables, i.e. whether it possibly could be affected by instantiation. This function may return true even when the type references no type variables because it isn't possible to explore all types fully in depth. There's no good reason for this function to use a dedicated property. An ObjectFlags flag would be better.

In scenarios that are heavy on union and intersection type instantiation, it might make sense to first call couldContainTypeVariables since the cached result would allow us to bail out quicker.

[amcasey]

Follow-up questions:

1. Why do we only set those flags on union and intersection types? It looks like we might do non-trivial work for other types?
2. Do we need both sets of flags? I would guess that only one of the two makes sense for any given type or that, if both make sense, only the || of the values matters.

Edit - offline responses:

1. Claim is that it's only expensive for union and intersection types.
2. Yes, the difference matters.