Remove unused scope from Walker
#1341
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The `scope` info here is entirely unused in the Glimmer codebase. It may be used in some AST transforms, but this is fairly unlikely, since it has only been available since Ember 3.16. Profiling template compilation highlighted the recursive walking of the whole tree for locals in scope during syntax parsing as a major cost in CPU usage, so the hope is that removing this will help.
This was referenced Oct 1, 2021
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The
scopeinfo here is entirely unused in the Glimmer codebase. It may be used in some AST transforms, but this is fairly unlikely, since it has only been available since Ember 3.16. Profiling template compilation highlighted the recursive walking of the whole tree for locals in scope during syntax parsing as a major cost in CPU usage, so the hope is that removing this will help.I also confirmed that this passes all of Ember's tests when integrating into Ember 3.28! 🎉
Here's the output of two runs (A and B) using the latest version of this branch on our repro repo. To summarize: this gets us back another ~8s closer to the baseline throughput.
ember-source@3.24.5ember-source@3.25.4ember-source@3.28.1@glimmer/compiler@0.65.3@glimmer/compiler@0.80.0@glimmer/compiler@master@glimmer/compiler@experiment(this PR)Note: There is something slightly odd happening – I suspect a quirk of the benchmark or of my machine setup, but haven't found what's causing it yet – where the 3.28 version will occasionally get "stuck" and have these blowup times. You can see that run A it showed up with a ~48s time on the
@glimmer/compiler@0.80.0variant, and on run B it showed up on theember-source@3.28.1variant.