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LibJS: Make sure that if expressions yield the correct value

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When evaluated as an expression "if (true) { 3 } else { 5 }"
should yield 3. This updates the bytecode interpreter to make
it so.
This commit is contained in:
Gunnar Beutner 2021-06-07 22:05:09 +02:00 • committed by Andreas Kling
parent 2c10bd72f2
commit 93eae063a1
4 changed files with 34 additions and 5 deletions
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11
Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp
View file

@ -344,24 +344,25 @@ Optional<Bytecode::Register> ReturnStatement::generate_bytecode(Bytecode::Genera
Optional<Bytecode::Register> IfStatement::generate_bytecode(Bytecode::Generator& generator) const
{
auto result_reg = generator.allocate_register();
auto predicate_reg = m_predicate->generate_bytecode(generator);
auto& if_jump = generator.emit<Bytecode::Op::JumpIfTrue>(*predicate_reg);
auto& else_jump = generator.emit<Bytecode::Op::JumpIfFalse>(*predicate_reg);
if_jump.set_target(generator.make_label());
(void)m_consequent->generate_bytecode(generator);
auto consequent_reg = m_consequent->generate_bytecode(generator);
generator.emit<Bytecode::Op::LoadRegister>(result_reg, *consequent_reg);
auto& end_jump = generator.emit<Bytecode::Op::Jump>();
else_jump.set_target(generator.make_label());
if (m_alternate) {
(void)m_alternate->generate_bytecode(generator);
auto alternative_reg = m_alternate->generate_bytecode(generator);
generator.emit<Bytecode::Op::LoadRegister>(result_reg, *alternative_reg);
}
end_jump.set_target(generator.make_label());
// FIXME: Do we need IfStatement to return the consequent/alternate result value?
// (That's what the AST interpreter currently does)
return {};
return result_reg;
}
Optional<Bytecode::Register> ContinueStatement::generate_bytecode(Bytecode::Generator& generator) const