mirror of
https://github.com/LadybirdBrowser/ladybird
synced 2026-04-27 10:07:15 +02:00
54a1a66112
Instead of storing a u32 index into a cache vector and looking up the cache at runtime through a chain of dependent loads (load Executable*, load vector data pointer, multiply index, add), store the actual cache pointer as a u64 directly in the instruction stream. A fixup pass (Executable::fixup_cache_pointers()) runs after Executable construction in both the Rust and C++ pipelines, walking the bytecode and replacing each index with the corresponding pointer. The cache pointer type is encoded in Bytecode.def (e.g. PropertyLookupCache*, GlobalVariableCache*) so the fixup switch is auto-generated by the Python Op code generator, making it impossible to forget updating the fixup when adding new cached instructions. This eliminates 3-4 dependent loads on every inline cache access in both the C++ interpreter and the assembly interpreter.
29 lines
1.4 KiB
Plaintext
29 lines
1.4 KiB
Plaintext
JS bytecode executable ""
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[ 0] 0: GetLexicalEnvironment dst:reg4
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[ 8] GetGlobal dst:reg6, identifier:f
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[ 20] Call dst:reg5, callee:reg6, this_value:Undefined, f, arguments:[Int32(1), Int32(2), Int32(3)]
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[ 50] End value:reg5
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JS bytecode executable "f"
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[ 0] 0: GetLexicalEnvironment dst:reg4
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[ 8] CreateVariable identifier:a, is_immutable:false, is_global:false, is_strict:false
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[ 18] CreateVariable identifier:b, is_immutable:false, is_global:false, is_strict:false
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[ 28] CreateVariable identifier:c, is_immutable:false, is_global:false, is_strict:false
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[ 38] InitializeLexicalBinding identifier:a, src:arg0
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[ 50] InitializeLexicalBinding identifier:b, src:arg1
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[ 68] InitializeLexicalBinding identifier:c, src:arg2
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[ 80] Mov dst:inner~0, src:Undefined
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[ 90] NewFunction dst:reg5, shared_function_data_index:0, lhs_name:inner
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[ a8] Mov dst:inner~0, src:reg5
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[ b8] Mov dst:reg6, src:inner~0
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[ c8] Call dst:reg5, callee:reg6, this_value:Undefined, inner
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[ e8] Return value:reg5
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JS bytecode executable "inner"
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[ 0] 0: GetLexicalEnvironment dst:reg4
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[ 8] GetBinding dst:reg5, identifier:a
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[ 20] GetBinding dst:reg6, identifier:b
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[ 38] Add dst:reg7, lhs:reg5, rhs:reg6
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[ 48] GetBinding dst:reg5, identifier:c
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[ 60] Add dst:reg6, lhs:reg7, rhs:reg5
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[ 70] Return value:reg6 |