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Code Issues Projects Releases Packages Wiki Activity Actions 10

LibJS/Bytecode: Store unwind contexts inside RegisterWindow

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Unwind contexts need to be preserved as we exit and re-enter a
generator.

For example, this would previously crash when returning from the try
statement after yielding as we lost the unwind context when yielding,
but still have a LeaveUnwindContext instruction from running
`perform_needed_unwinds` when generating the return statement.
```js
function* a() {
    try {
        return (yield 1);
    } catch {}
}

iter = a();
iter.next();
iter.next();
```
This commit is contained in:
Luke Wilde 2022-11-25 23:15:44 +00:00 • committed by Andreas Kling
parent b914680f0c
commit 277132f70d
Notes: sideshowbarker 2024-07-17 04:01:41 +09:00
2 changed files with 9 additions and 8 deletions
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14
Userland/Libraries/LibJS/Bytecode/Interpreter.cpp
View file

@ -65,7 +65,7 @@ Interpreter::ValueAndFrame Interpreter::run_and_return_frame(Executable const& e
if (in_frame)
m_register_windows.append(in_frame);
else
m_register_windows.append(make<RegisterWindow>(MarkedVector<Value>(vm().heap()), MarkedVector<Environment*>(vm().heap()), MarkedVector<Environment*>(vm().heap())));
m_register_windows.append(make<RegisterWindow>(MarkedVector<Value>(vm().heap()), MarkedVector<Environment*>(vm().heap()), MarkedVector<Environment*>(vm().heap()), Vector<UnwindInfo> {}));
registers().resize(executable.number_of_registers);
@ -81,9 +81,9 @@ Interpreter::ValueAndFrame Interpreter::run_and_return_frame(Executable const& e
if (ran_or_error.is_error()) {
auto exception_value = *ran_or_error.throw_completion().value();
m_saved_exception = make_handle(exception_value);
if (m_unwind_contexts.is_empty())
if (unwind_contexts().is_empty())
break;
auto& unwind_context = m_unwind_contexts.last();
auto& unwind_context = unwind_contexts().last();
if (unwind_context.executable != m_current_executable)
break;
if (unwind_context.handler) {
@ -92,7 +92,7 @@ Interpreter::ValueAndFrame Interpreter::run_and_return_frame(Executable const& e
// If there's no finalizer, there's nowhere for the handler block to unwind to, so the unwind context is no longer needed.
if (!unwind_context.finalizer)
m_unwind_contexts.take_last();
unwind_contexts().take_last();
accumulator() = exception_value;
m_saved_exception = {};
@ -101,7 +101,7 @@ Interpreter::ValueAndFrame Interpreter::run_and_return_frame(Executable const& e
}
if (unwind_context.finalizer) {
m_current_block = unwind_context.finalizer;
m_unwind_contexts.take_last();
unwind_contexts().take_last();
will_jump = true;
break;
}
@ -179,12 +179,12 @@ Interpreter::ValueAndFrame Interpreter::run_and_return_frame(Executable const& e
void Interpreter::enter_unwind_context(Optional<Label> handler_target, Optional<Label> finalizer_target)
{
m_unwind_contexts.empend(m_current_executable, handler_target.has_value() ? &handler_target->block() : nullptr, finalizer_target.has_value() ? &finalizer_target->block() : nullptr);
unwind_contexts().empend(m_current_executable, handler_target.has_value() ? &handler_target->block() : nullptr, finalizer_target.has_value() ? &finalizer_target->block() : nullptr);
}
void Interpreter::leave_unwind_context()
{
m_unwind_contexts.take_last();
unwind_contexts().take_last();
}
ThrowCompletionOr<void> Interpreter::continue_pending_unwind(Label const& resume_label)

3
Userland/Libraries/LibJS/Bytecode/Interpreter.h
View file

@ -22,6 +22,7 @@ struct RegisterWindow {
MarkedVector<Value> registers;
MarkedVector<Environment*> saved_lexical_environments;
MarkedVector<Environment*> saved_variable_environments;
Vector<UnwindInfo> unwind_contexts;
};
class Interpreter {
@ -52,6 +53,7 @@ public:
auto& saved_lexical_environment_stack() { return window().saved_lexical_environments; }
auto& saved_variable_environment_stack() { return window().saved_variable_environments; }
auto& unwind_contexts() { return window().unwind_contexts; }
void jump(Label const& label)
{
@ -98,7 +100,6 @@ private:
Optional<BasicBlock const*> m_pending_jump;
Value m_return_value;
Executable const* m_current_executable { nullptr };
Vector<UnwindInfo> m_unwind_contexts;
Handle<Value> m_saved_exception;
OwnPtr<JS::Interpreter> m_ast_interpreter;
BasicBlock const* m_current_block { nullptr };