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LibJS: Support array rest elements in the bytecode interpreter

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This commit is contained in:
Matthew Olsson 2021-06-13 14:06:26 -07:00 • committed by Andreas Kling
parent 7983324639
commit 57b9a228ab
4 changed files with 172 additions and 77 deletions
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69
Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp
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@ -729,11 +729,61 @@ static void generate_array_binding_pattern_bytecode(Bytecode::Generator& generat
auto temp_iterator_result_reg = generator.allocate_register();
auto assign_accumulator_to_alias = [&](auto& alias) {
alias.visit(
[&](Empty) {
// This element is an elision
},
[&](NonnullRefPtr<Identifier> const& identifier) {
auto interned_index = generator.intern_string(identifier->string());
generator.emit<Bytecode::Op::SetVariable>(interned_index);
},
[&](NonnullRefPtr<BindingPattern> const& pattern) {
// Store the accumulator value in a permanent register
auto target_reg = generator.allocate_register();
generator.emit<Bytecode::Op::Store>(target_reg);
generate_binding_pattern_bytecode(generator, pattern, target_reg);
});
};
for (auto& [name, alias, initializer, is_rest] : pattern.entries) {
VERIFY(name.has<Empty>());
if (is_rest)
TODO();
if (is_rest) {
if (first) {
// The iterator has not been called, and is thus known to be not exhausted
generator.emit<Bytecode::Op::Load>(iterator_reg);
generator.emit<Bytecode::Op::IteratorToArray>();
} else {
auto& if_exhausted_block = generator.make_block();
auto& if_not_exhausted_block = generator.make_block();
auto& continuation_block = generator.make_block();
generator.emit<Bytecode::Op::Load>(is_iterator_exhausted_register);
generator.emit<Bytecode::Op::JumpConditional>().set_targets(
Bytecode::Label { if_exhausted_block },
Bytecode::Label { if_not_exhausted_block });
generator.switch_to_basic_block(if_exhausted_block);
generator.emit<Bytecode::Op::NewArray>();
generator.emit<Bytecode::Op::Jump>().set_targets(
Bytecode::Label { continuation_block },
{});
generator.switch_to_basic_block(if_not_exhausted_block);
generator.emit<Bytecode::Op::Load>(iterator_reg);
generator.emit<Bytecode::Op::IteratorToArray>();
generator.emit<Bytecode::Op::Jump>().set_targets(
Bytecode::Label { continuation_block },
{});
generator.switch_to_basic_block(continuation_block);
}
assign_accumulator_to_alias(alias);
return;
}
// In the first iteration of the loop, a few things are true which can save
// us some bytecode:
@ -790,20 +840,7 @@ static void generate_array_binding_pattern_bytecode(Bytecode::Generator& generat
// pattern if necessary.
generator.switch_to_basic_block(create_binding_block);
alias.visit(
[&](Empty) {
// This element is an elision
},
[&](NonnullRefPtr<Identifier> const& identifier) {
auto interned_index = generator.intern_string(identifier->string());
generator.emit<Bytecode::Op::SetVariable>(interned_index);
},
[&](NonnullRefPtr<BindingPattern> const& pattern) {
// Store the accumulator value in a permanent register
auto target_reg = generator.allocate_register();
generator.emit<Bytecode::Op::Store>(target_reg);
generate_binding_pattern_bytecode(generator, pattern, target_reg);
});
assign_accumulator_to_alias(alias);
first = false;
}