[Serialization] Do less work checking if a value can be deserialized. #9666
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DougGregor
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May 16, 2017
| nameAndDependencyIDs.slice(numNameComponentsBiased); | ||
| } else { | ||
| name = baseName; | ||
| nameAndDependencyIDs = nameAndDependencyIDs.drop_front(); |
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The change of meaning of nameAndDependencyIDs here really threw me. The code is correct, but kinda hard to read. What about just defining
auto dependencyIDs = nameAndDependencyIDs.slice(numNameComponentsBiased);
?
lib/Serialization/Serialization.cpp
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| SmallVector<Type, 2> result; | ||
| ty.visit([&](CanType next) { | ||
| if (auto *nominal = next->getAnyNominal()) | ||
| result.push_back(nominal->getDeclaredType()); |
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How about getDeclaredInterfaceType here, so we don't have any archetypes in there that would force deserialization of a generic environment?
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getDeclaredType should already be using UnboundGenericType, no? I wanted the absolute smallest type.
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…but that probably doesn't make sense for nested types. Okay, getDeclaredInterfaceType it is.
lib/Serialization/Serialization.cpp
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| if (auto *nominal = next->getAnyNominal()) | ||
| result.push_back(nominal->getDeclaredType()); | ||
| }); | ||
| return result; |
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Should you unique the types in result?
Previously we recorded the canonical type of the declaration and made sure we could deserialize that, but that's a lot of extra work building up intermediate types that we mostly don't need. Instead, record smaller types that represent the possible points of failure--- right now, just the nominal types that are referenced by the value (function, variable/constant, subscript, or initializer). I chose to use types instead of declarations here because types can potentially encode more complicated constraints later (such as generic types checking that their arguments still conform). This gains us back 20% of type-checking time on a compile-time microbenchmark: `let _ = [1, 2]`. I expect the effect is less dramatic the more expressions you have, since we only need to deserialize things once.
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macOS full test on prior version (passed!) @swift-ci Please smoke test |
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https://ci.swift.org/job/swift-PR-osx-smoke-test/8231/ |
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@jrose-apple Strange... I'll disable the test. |
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@jrose-apple Should be clear now. |
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@swift-ci Please smoke test macOS |
jrose-apple
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May 17, 2017
…swiftlang#9666) Previously we recorded the canonical type of the declaration and made sure we could deserialize that, but that's a lot of extra work building up intermediate types that we mostly don't need. Instead, record smaller types that represent the possible points of failure--- right now, just the nominal types that are referenced by the value (function, variable/constant, subscript, or initializer). I chose to use types instead of declarations here because types can potentially encode more complicated constraints later (such as generic types checking that their arguments still conform). This gains us back 20% of type-checking time on a compile-time microbenchmark: `let _ = [1, 2]`. I expect the effect is less dramatic the more expressions you have, since we only need to deserialize things once.
This was referenced May 17, 2017
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Previously we recorded the canonical type of the declaration and made sure we could deserialize that, but that's a lot of extra work building up intermediate types that we mostly don't need. Instead, record smaller types that represent the possible points of failure—right now, just the nominal types that are referenced by the value (function, variable/constant, subscript, or initializer). I chose to use types instead of declarations here because types can potentially encode more complicated constraints later (such as generic types checking that their arguments still conform).
This gains us back 20% of type-checking time on a compile-time microbenchmark:
let _ = [1, 2]. I expect the effect is less dramatic the more expressions you have, since we only need to deserialize things once.