mirror of
https://github.com/LadybirdBrowser/ladybird
synced 2026-04-30 11:37:16 +02:00
18c40a1328
Fix two bugs in the Rust bytecode codegen:
1. has_parameter_expressions incorrectly treated any destructuring
parameter as a "parameter expression", when it should only do so
for patterns that contain expressions (defaults or computed keys).
This caused an unnecessary CreateLexicalEnvironment for simple
destructuring like `function f({a, b}) {}`. The same bug existed
in both codegen.rs and lib.rs (SFD metadata computation).
2. emit_set_variable used is_local_lexically_declared(index) for
argument locals, but that function indexes into the local_variables
array using the argument's index, checking the wrong variable.
This caused spurious ThrowIfTDZ instructions when assigning to
function arguments that happened to share an index with an
uninitialized let/const variable.
21 lines
1.0 KiB
Plaintext
21 lines
1.0 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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[ 18] NewObject dst:reg7
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[ 28] InitObjectLiteralProperty object:reg7, property:captured, src:Int32(1), shape_cache_index:0, property_slot:0
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[ 40] InitObjectLiteralProperty object:reg7, property:local, src:Int32(2), shape_cache_index:0, property_slot:1
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[ 58] CacheObjectShape object:reg7
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[ 68] Call dst:reg5, callee:reg6, this_value:Undefined, f, arguments:[reg7]
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[ 90] 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:captured, is_immutable:false, is_global:false, is_strict:false
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[ 18] ThrowIfNullish src:arg0
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[ 20] GetById dst:reg5, base:arg0, property:captured
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[ 38] InitializeLexicalBinding identifier:captured, src:reg5
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[ 50] GetById dst:reg5, base:arg0, property:local
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[ 68] Mov dst:local~0, src:reg5
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[ 78] NewFunction dst:reg5, shared_function_data_index:0
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[ 90] Return value:reg5
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