mirror of
https://github.com/LadybirdBrowser/ladybird
synced 2026-04-26 01:35:08 +02:00
51758f3022
Generator::allocate_register used to scan the free pool to find the lowest-numbered register and then Vec::remove it, making every allocation O(n) in the size of the pool. When loading https://x.com/ on my Linux machine, we spent ~800ms in this function alone! This logic only existed to match the C++ register allocation ordering while transitioning from C++ to Rust in the LibJS compiler, so now we can simply get rid of it and make it instant. :^) So drop the "always hand out the lowest-numbered free register" policy and use the pool as a plain LIFO stack. Pushing and popping the back of the Vec are both O(1), and peak register usage is unchanged since the policy only affects which specific register gets reused, not how aggressively.
87 lines
2.4 KiB
Plaintext
87 lines
2.4 KiB
Plaintext
$fc23251f switch-scoping.js:15:1
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Registers: 11
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Blocks: 1
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Constants:
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[0] = Undefined
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[1] = Int32(1)
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[2] = Int32(2)
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block0:
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[ 0] GetGlobal dst:reg6, `console`
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[ 18] GetById dst:reg7, base:reg6, `log` (console.log)
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[ 38] GetGlobal dst:reg9, `switchWithBlockDecl`
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[ 50] Call dst:reg8, callee:reg9, this_value:Undefined, switchWithBlockDecl, arguments:[Int32(1)]
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[ 78] Call dst:reg5, callee:reg7, this_value:reg6, console.log, arguments:[reg8]
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[ a0] GetGlobal dst:reg6, `console`
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[ b8] GetById dst:reg8, base:reg6, `log` (console.log)
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[ d8] GetGlobal dst:reg10, `switchWithBlockDecl`
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[ f0] Call dst:reg9, callee:reg10, this_value:Undefined, switchWithBlockDecl, arguments:[Int32(2)]
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[ 118] Call dst:reg7, callee:reg8, this_value:reg6, console.log, arguments:[reg9]
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[ 140] End value:reg7
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switchWithBlockDecl$2b5ecfcd switch-scoping.js:2:5
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Registers: 7
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Blocks: 7
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Locals: result~0
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Constants:
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[0] = Undefined
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[1] = Int32(1)
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[2] = Int32(2)
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[3] = String("one")
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[4] = String("two")
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block0:
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[ 0] GetLexicalEnvironment dst:reg4
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[ 8] Mov dst:result~0, src:Undefined
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[ 18] CreateLexicalEnvironment dst:reg5, parent:reg4, capacity:0
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[ 28] CreateMutableBinding environment:reg5, `a`, can_be_deleted:false
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[ 38] CreateMutableBinding environment:reg5, `b`, can_be_deleted:false
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block1:
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[ 48] JumpStrictlyEquals lhs:Int32(1), rhs:arg0, true_target:block4, false_target:block2
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block2:
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[ 60] JumpStrictlyEquals lhs:Int32(2), rhs:arg0, true_target:block5, false_target:block3
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block3:
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[ 78] Jump target:block6
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block4:
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[ 80] InitializeLexicalBinding `a`, src:String("one")
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[ 98] NewFunction dst:reg6, shared_function_data_index:0 (result)
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[ b0] Mov dst:result~0, src:reg6
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[ c0] Jump target:block6
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block5:
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[ c8] InitializeLexicalBinding `b`, src:String("two")
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[ e0] NewFunction dst:reg6, shared_function_data_index:1 (result)
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[ f8] Mov dst:result~0, src:reg6
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block6:
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[ 108] SetLexicalEnvironment environment:reg4
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[ 110] Call dst:reg5, callee:result~0, this_value:Undefined, result
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[ 130] Return value:reg5
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result$9ed940b6 switch-scoping.js:6:22
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Registers: 6
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Blocks: 1
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block0:
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[ 0] GetBinding dst:reg5, `a`
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[ 18] Return value:reg5
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result$78d6c64d switch-scoping.js:10:22
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Registers: 6
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Blocks: 1
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block0:
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[ 0] GetBinding dst:reg5, `b`
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[ 18] Return value:reg5
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"one"
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"two"
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