LibJS: Convert Instruction::execute in bytecode to ThrowCompletionOr

This allows us to use TRY in these functions :^).

1 files changed, 25 insertions, 19 deletions

diff --git a/Userland/Libraries/LibJS/Bytecode/Interpreter.cpp b/Userland/Libraries/LibJS/Bytecode/Interpreter.cpp
index 3dfb8c509c..5387b05f7f 100644
--- a/Userland/Libraries/LibJS/Bytecode/Interpreter.cpp
+++ b/Userland/Libraries/LibJS/Bytecode/Interpreter.cpp
@@ -44,6 +44,7 @@ Interpreter::ValueAndFrame Interpreter::run_and_return_frame(Executable const& e
     dbgln_if(JS_BYTECODE_DEBUG, "Bytecode::Interpreter will run unit {:p}", &executable);
 
     TemporaryChange restore_executable { m_current_executable, &executable };
+    VERIFY(m_saved_exception.is_null());
 
     ExecutionContext execution_context(vm().heap());
     if (vm().execution_context_stack().is_empty() || !vm().running_execution_context().lexical_environment) {
@@ -76,9 +77,17 @@ Interpreter::ValueAndFrame Interpreter::run_and_return_frame(Executable const& e
         bool will_return = false;
         while (!pc.at_end()) {
             auto& instruction = *pc;
-            instruction.execute(*this);
+            auto ran_or_error = instruction.execute(*this);
             if (vm().exception()) {
-                m_saved_exception = {};
+                if (!ran_or_error.is_error()) {
+                    // FIXME: Until exception is removed use this to make sure we always get the error if there is one.
+                    ran_or_error = throw_completion(vm().exception()->value());
+                }
+                vm().clear_exception();
+            }
+            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())
                     break;
                 auto& unwind_context = m_unwind_contexts.last();
@@ -87,8 +96,8 @@ Interpreter::ValueAndFrame Interpreter::run_and_return_frame(Executable const& e
                 if (unwind_context.handler) {
                     block = unwind_context.handler;
                     unwind_context.handler = nullptr;
-                    accumulator() = vm().exception()->value();
-                    vm().clear_exception();
+                    accumulator() = exception_value;
+                    m_saved_exception = {};
                     will_jump = true;
                     break;
                 }
@@ -96,8 +105,6 @@ Interpreter::ValueAndFrame Interpreter::run_and_return_frame(Executable const& e
                     block = unwind_context.finalizer;
                     m_unwind_contexts.take_last();
                     will_jump = true;
-                    m_saved_exception = Handle<Exception>::create(vm().exception());
-                    vm().clear_exception();
                     break;
                 }
             }
@@ -119,7 +126,7 @@ Interpreter::ValueAndFrame Interpreter::run_and_return_frame(Executable const& e
         if (pc.at_end() && !will_jump)
             break;
 
-        if (vm().exception())
+        if (!m_saved_exception.is_null())
             break;
     }
 
@@ -142,12 +149,6 @@ Interpreter::ValueAndFrame Interpreter::run_and_return_frame(Executable const& e
         m_manually_entered_frames.take_last();
     }
 
-    Value exception_value;
-    if (vm().exception()) {
-        exception_value = vm().exception()->value();
-        vm().clear_exception();
-    }
-
     auto return_value = m_return_value.value_or(js_undefined());
     m_return_value = {};
 
@@ -164,8 +165,11 @@ Interpreter::ValueAndFrame Interpreter::run_and_return_frame(Executable const& e
 
     vm().finish_execution_generation();
 
-    if (!exception_value.is_empty())
-        return { throw_completion(exception_value), move(frame) };
+    if (!m_saved_exception.is_null()) {
+        Value thrown_value = m_saved_exception.value();
+        m_saved_exception = {};
+        return { throw_completion(thrown_value), move(frame) };
+    }
 
     return { return_value, move(frame) };
 }
@@ -180,14 +184,16 @@ void Interpreter::leave_unwind_context()
     m_unwind_contexts.take_last();
 }
 
-void Interpreter::continue_pending_unwind(Label const& resume_label)
+ThrowCompletionOr<void> Interpreter::continue_pending_unwind(Label const& resume_label)
 {
     if (!m_saved_exception.is_null()) {
-        vm().set_exception(*m_saved_exception.cell());
+        auto result = throw_completion(m_saved_exception.value());
         m_saved_exception = {};
-    } else {
-        jump(resume_label);
+        return result;
     }
+
+    jump(resume_label);
+    return {};
 }
 
 AK::Array<OwnPtr<PassManager>, static_cast<UnderlyingType<Interpreter::OptimizationLevel>>(Interpreter::OptimizationLevel::__Count)> Interpreter::s_optimization_pipelines {};