Reduce allocations from creating MissingTokenWithTrivia objects #75404
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This method accounts for 0.7% of allocations in the roslyn csharp editing speedometer test profile I'm looking at. In addition to caching tokens < LastTokenWithWellKnownText similar to what is already done, the SyntaxKind.IdentifierToken case is handled as it's very commonly hit too. Local testing of opening LanguageParser and typing in a new method reduced the number of MissingTokenWithTrivia from over 1 million to zero.
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Oct 8, 2024
| @@ -118,6 +118,20 @@ internal static SyntaxToken Create(SyntaxKind kind, GreenNode leading, GreenNode | |||
| return new SyntaxTokenWithTrivia(kind, leading, trailing); | |||
| } | |||
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| internal static SyntaxToken CreateMissing(SyntaxKind kind) | |||
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Would it be better to instead have just one CreateMissing(SyntaxKind kind, GreenNode leading, GreenNode trailing) and do the optimization if leading is null && trailing is null?
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I'm flexible to whatever you folks want, but that's the way I started and I switched to this because:
- Two less null checks in the 99% case that I see called
- This mimics what the two Create methods do right above it by having one that handles leading/trailing and one that doesn't take them in.
This was referenced Oct 22, 2024
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This method accounts for 0.7% of allocations in the roslyn csharp editing speedometer test profile I'm looking at. In addition to caching tokens < LastTokenWithWellKnownText similar to what is already done, the SyntaxKind.IdentifierToken case is handled as it's very commonly hit too. Local testing of opening LanguageParser and typing in a new method reduced the number of MissingTokenWithTrivia from over 1 million to zero.
*** allocations in speedometer profile ***
