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LibJS: Mark locals as outside TDZ immediately after initializing

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This avoids emitting TDZ checks for multiple bindings declared and
referenced within one variable declaration, i.e:

    var foo = 0, bar = foo;

In the above case, we'd emit an unnecessary TDZ check for the second
reference to `foo`.
This commit is contained in:
Andreas Kling 2025-03-20 17:19:50 -05:00 committed by Alexander Kalenik
parent 01031bcccb
commit b971e1ece0
1 changed files with 0 additions and 2 deletions
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2
Libraries/LibJS/Bytecode/ASTCodegen.cpp
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@ -1616,9 +1616,7 @@ Bytecode::CodeGenerationErrorOr<Optional<ScopedOperand>> VariableDeclaration::ge
} else if (m_declaration_kind != DeclarationKind::Var) { } else if (m_declaration_kind != DeclarationKind::Var) {
(void)TRY(assign_value_to_variable_declarator(generator, declarator, *this, generator.add_constant(js_undefined()))); (void)TRY(assign_value_to_variable_declarator(generator, declarator, *this, generator.add_constant(js_undefined())));
} }
}
for (auto& declarator : m_declarations) {
if (auto const* identifier = declarator->target().get_pointer<NonnullRefPtr<Identifier const>>()) { if (auto const* identifier = declarator->target().get_pointer<NonnullRefPtr<Identifier const>>()) {
if ((*identifier)->is_local()) { if ((*identifier)->is_local()) {
generator.set_local_initialized((*identifier)->local_variable_index()); generator.set_local_initialized((*identifier)->local_variable_index());