LibJS: Make ExecutionContext::function_name a GCPtr<PrimitiveString>

This required setting things up so that all function objects can plop
a PrimitiveString there instead of an AK string.

This is a step towards making ExecutionContext easier to allocate.

Userland/Libraries/LibJS/Console.cpp

@@ -142,9 +142,9 @@ ThrowCompletionOr<Value> Console::trace()
     // NOTE: -2 to skip the console.trace() execution context
     for (ssize_t i = execution_context_stack.size() - 2; i >= 0; --i) {
         auto const& function_name = execution_context_stack[i]->function_name;
-        trace.stack.append(function_name.is_empty()
+        trace.stack.append((!function_name || function_name->is_empty())
                 ? "<anonymous>"_string
-                : TRY_OR_THROW_OOM(vm, String::from_deprecated_string(function_name)));
+                : function_name->utf8_string());
     }
 
     // 2. Optionally, let formattedData be the result of Formatter(data), and incorporate formattedData as a label for trace.

Userland/Libraries/LibJS/Runtime/ECMAScriptFunctionObject.cpp

@@ -333,8 +333,10 @@ void ECMAScriptFunctionObject::initialize(Realm& realm)
     //       which must give the properties in chronological order which in this case is the order they
     //       are defined in the spec.
 
+    m_name_string = PrimitiveString::create(vm, m_name);
+
     MUST(define_property_or_throw(vm.names.length, { .value = Value(m_function_length), .writable = false, .enumerable = false, .configurable = true }));
-    MUST(define_property_or_throw(vm.names.name, { .value = PrimitiveString::create(vm, m_name.is_null() ? "" : m_name), .writable = false, .enumerable = false, .configurable = true }));
+    MUST(define_property_or_throw(vm.names.name, { .value = m_name_string, .writable = false, .enumerable = false, .configurable = true }));
 
     if (!m_is_arrow_function) {
         Object* prototype = nullptr;
@@ -936,7 +938,7 @@ ThrowCompletionOr<void> ECMAScriptFunctionObject::prepare_for_ordinary_call(Exec
 
     // 3. Set the Function of calleeContext to F.
     callee_context.function = this;
-    callee_context.function_name = m_name;
+    callee_context.function_name = m_name_string;
 
     // 4. Let calleeRealm be F.[[Realm]].
     auto callee_realm = m_realm;
@@ -1243,6 +1245,7 @@ void ECMAScriptFunctionObject::set_name(DeprecatedFlyString const& name)
     VERIFY(!name.is_null());
     auto& vm = this->vm();
     m_name = name;
-    MUST(define_property_or_throw(vm.names.name, { .value = PrimitiveString::create(vm, m_name), .writable = false, .enumerable = false, .configurable = true }));
+    m_name_string = PrimitiveString::create(vm, m_name);
+    MUST(define_property_or_throw(vm.names.name, { .value = m_name_string, .writable = false, .enumerable = false, .configurable = true }));
 }
 }

Userland/Libraries/LibJS/Runtime/ECMAScriptFunctionObject.h

@@ -112,6 +112,8 @@ private:
     ThrowCompletionOr<void> function_declaration_instantiation();
 
     DeprecatedFlyString m_name;
+    GCPtr<PrimitiveString> m_name_string;
+
     GCPtr<Bytecode::Executable> m_bytecode_executable;
     Vector<NonnullGCPtr<Bytecode::Executable>> m_default_parameter_bytecode_executables;
     i32 m_function_length { 0 };

Userland/Libraries/LibJS/Runtime/Error.cpp

@@ -85,7 +85,7 @@ void Error::populate_stack()
         if (element.source_range.has_value())
             range = element.source_range.value();
         TracebackFrame frame {
-            .function_name = context->function_name,
+            .function_name = context->function_name ? context->function_name->deprecated_string() : "",
             .source_range_storage = range,
         };
 

Userland/Libraries/LibJS/Runtime/ExecutionContext.cpp

@@ -53,6 +53,7 @@ void ExecutionContext::visit_edges(Cell::Visitor& visitor)
     visitor.visit(this_value);
     if (instruction_stream_iterator.has_value())
         visitor.visit(const_cast<Bytecode::Executable*>(instruction_stream_iterator.value().executable()));
+    visitor.visit(function_name);
     script_or_module.visit(
         [](Empty) {},
         [&](auto& script_or_module) {

Userland/Libraries/LibJS/Runtime/ExecutionContext.h

@@ -49,7 +49,7 @@ public:
     GCPtr<Cell> context_owner;
 
     Optional<Bytecode::InstructionStreamIterator> instruction_stream_iterator;
-    DeprecatedFlyString function_name;
+    GCPtr<PrimitiveString> function_name;
     Value this_value;
     MarkedVector<Value> arguments;
     MarkedVector<Value> local_variables;

Userland/Libraries/LibJS/Runtime/NativeFunction.cpp

@@ -17,6 +17,20 @@ namespace JS {
 
 JS_DEFINE_ALLOCATOR(NativeFunction);
 
+void NativeFunction::initialize(Realm& realm)
+{
+    Base::initialize(realm);
+    m_name_string = PrimitiveString::create(vm(), m_name);
+}
+
+void NativeFunction::visit_edges(Cell::Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    visitor.visit(m_native_function);
+    visitor.visit(m_realm);
+    visitor.visit(m_name_string);
+}
+
 // 10.3.3 CreateBuiltinFunction ( behaviour, length, name, additionalInternalSlotsList [ , realm [ , prototype [ , prefix ] ] ] ), https://tc39.es/ecma262/#sec-createbuiltinfunction
 // NOTE: This doesn't consider additionalInternalSlotsList, which is rarely used, and can either be implemented using only the `function` lambda, or needs a NativeFunction subclass.
 NonnullGCPtr<NativeFunction> NativeFunction::create(Realm& allocating_realm, Function<ThrowCompletionOr<Value>(VM&)> behaviour, i32 length, PropertyKey const& name, Optional<Realm*> realm, Optional<Object*> prototype, Optional<StringView> const& prefix)
@@ -111,7 +125,7 @@ ThrowCompletionOr<Value> NativeFunction::internal_call(Value this_argument, Read
 
     // 4. Set the Function of calleeContext to F.
     callee_context.function = this;
-    callee_context.function_name = m_name;
+    callee_context.function_name = m_name_string;
 
     // 5. Let calleeRealm be F.[[Realm]].
     auto callee_realm = m_realm;
@@ -175,7 +189,7 @@ ThrowCompletionOr<NonnullGCPtr<Object>> NativeFunction::internal_construct(Reado
 
     // 4. Set the Function of calleeContext to F.
     callee_context.function = this;
-    callee_context.function_name = m_name;
+    callee_context.function_name = m_name_string;
 
     // 5. Let calleeRealm be F.[[Realm]].
     auto callee_realm = m_realm;

Userland/Libraries/LibJS/Runtime/NativeFunction.h

@@ -48,16 +48,14 @@ protected:
     NativeFunction(DeprecatedFlyString name, JS::GCPtr<JS::HeapFunction<ThrowCompletionOr<Value>(VM&)>>, Object& prototype);
     explicit NativeFunction(Object& prototype);
 
-    virtual void visit_edges(Cell::Visitor& visitor) override
-    {
-        Base::visit_edges(visitor);
-        visitor.visit(m_native_function);
-    }
+    virtual void initialize(Realm&) override;
+    virtual void visit_edges(Cell::Visitor& visitor) override;
 
 private:
     virtual bool is_native_function() const final { return true; }
 
     DeprecatedFlyString m_name;
+    GCPtr<PrimitiveString> m_name_string;
     Optional<DeprecatedFlyString> m_initial_name; // [[InitialName]]
     JS::GCPtr<JS::HeapFunction<ThrowCompletionOr<Value>(VM&)>> m_native_function;
     GCPtr<Realm> m_realm;

Userland/Libraries/LibJS/Runtime/VM.cpp

@@ -749,9 +749,9 @@ void VM::dump_backtrace() const
         auto& frame = m_execution_context_stack[i];
         if (frame->instruction_stream_iterator.has_value() && frame->instruction_stream_iterator->source_code()) {
             auto source_range = frame->instruction_stream_iterator->source_range().realize();
-            dbgln("-> {} @ {}:{},{}", frame->function_name, source_range.filename(), source_range.start.line, source_range.start.column);
+            dbgln("-> {} @ {}:{},{}", frame->function_name ? frame->function_name->utf8_string() : ""_string, source_range.filename(), source_range.start.line, source_range.start.column);
         } else {
-            dbgln("-> {}", frame->function_name);
+            dbgln("-> {}", frame->function_name ? frame->function_name->utf8_string() : ""_string);
         }
     }
 }