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LibJS: Move prepare_for_ordinary_call() to ECMAScriptFunctionObject

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Now that it only needs to deal with ECMAScriptFunctionObject via
internal_call() / internal_construct(), we can:

- Remove the generic FunctionObject parameter
- Move it from the VM to ECMAScriptFunctionObject
- Make it private
This commit is contained in:
Linus Groh 2021-10-08 21:14:22 +01:00
parent cf168fac50
commit 25bcd36116
4 changed files with 62 additions and 60 deletions
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62
Userland/Libraries/LibJS/Runtime/ECMAScriptFunctionObject.cpp
View file

@ -113,7 +113,7 @@ ThrowCompletionOr<Value> ECMAScriptFunctionObject::internal_call(Value this_argu
callee_context.current_node = interpreter->current_node();
// 2. Let calleeContext be PrepareForOrdinaryCall(F, undefined).
vm.prepare_for_ordinary_call(*this, callee_context, nullptr);
prepare_for_ordinary_call(callee_context, nullptr);
// NOTE: We throw if the end of the native stack is reached, so unlike in the spec this _does_ need an exception check.
if (auto* exception = vm.exception())
@ -188,7 +188,7 @@ ThrowCompletionOr<Object*> ECMAScriptFunctionObject::internal_construct(MarkedVa
callee_context.current_node = interpreter->current_node();
// 4. Let calleeContext be PrepareForOrdinaryCall(F, newTarget).
vm.prepare_for_ordinary_call(*this, callee_context, &new_target);
prepare_for_ordinary_call(callee_context, &new_target);
// NOTE: We throw if the end of the native stack is reached, so unlike in the spec this _does_ need an exception check.
if (auto* exception = vm.exception())
@ -557,6 +557,64 @@ ThrowCompletionOr<void> ECMAScriptFunctionObject::function_declaration_instantia
return {};
}
// 10.2.1.1 PrepareForOrdinaryCall ( F, newTarget ), https://tc39.es/ecma262/#sec-prepareforordinarycall
void ECMAScriptFunctionObject::prepare_for_ordinary_call(ExecutionContext& callee_context, Object* new_target)
{
auto& vm = this->vm();
// Non-standard
callee_context.is_strict_mode = m_strict;
// 1. Let callerContext be the running execution context.
// 2. Let calleeContext be a new ECMAScript code execution context.
// NOTE: In the specification, PrepareForOrdinaryCall "returns" a new callee execution context.
// To avoid heap allocations, we put our ExecutionContext objects on the C++ stack instead.
// Whoever calls us should put an ExecutionContext on their stack and pass that as the `callee_context`.
// 3. Set the Function of calleeContext to F.
callee_context.function = this;
callee_context.function_name = m_name;
// 4. Let calleeRealm be F.[[Realm]].
auto* callee_realm = m_realm;
// NOTE: This non-standard fallback is needed until we can guarantee that literally
// every function has a realm - especially in LibWeb that's sometimes not the case
// when a function is created while no JS is running, as we currently need to rely on
// that (:acid2:, I know - see set_event_handler_attribute() for an example).
// If there's no 'current realm' either, we can't continue and crash.
if (!callee_realm)
callee_realm = vm.current_realm();
VERIFY(callee_realm);
// 5. Set the Realm of calleeContext to calleeRealm.
callee_context.realm = callee_realm;
// 6. Set the ScriptOrModule of calleeContext to F.[[ScriptOrModule]].
// FIXME: Our execution context struct currently does not track this item.
// 7. Let localEnv be NewFunctionEnvironment(F, newTarget).
auto* local_environment = new_function_environment(new_target);
// 8. Set the LexicalEnvironment of calleeContext to localEnv.
callee_context.lexical_environment = local_environment;
// 9. Set the VariableEnvironment of calleeContext to localEnv.
callee_context.variable_environment = local_environment;
// 10. Set the PrivateEnvironment of calleeContext to F.[[PrivateEnvironment]].
// FIXME: We currently don't support private environments.
// 11. If callerContext is not already suspended, suspend callerContext.
// FIXME: We don't have this concept yet.
// 12. Push calleeContext onto the execution context stack; calleeContext is now the running execution context.
vm.push_execution_context(callee_context, global_object());
// 13. NOTE: Any exception objects produced after this point are associated with calleeRealm.
// 14. Return calleeContext. (See NOTE above about how contexts are allocated on the C++ stack.)
}
// 10.2.1.4 OrdinaryCallEvaluateBody ( F, argumentsList ), https://tc39.es/ecma262/#sec-ordinarycallevaluatebody
Completion ECMAScriptFunctionObject::ordinary_call_evaluate_body()
{

3
Userland/Libraries/LibJS/Runtime/ECMAScriptFunctionObject.h
View file

@ -82,8 +82,9 @@ private:
virtual FunctionEnvironment* new_function_environment(Object* new_target) override;
virtual void visit_edges(Visitor&) override;
ThrowCompletionOr<void> function_declaration_instantiation(Interpreter*);
void prepare_for_ordinary_call(ExecutionContext& callee_context, Object* new_target);
Completion ordinary_call_evaluate_body();
ThrowCompletionOr<void> function_declaration_instantiation(Interpreter*);
// Internal Slots of ECMAScript Function Objects, https://tc39.es/ecma262/#table-internal-slots-of-ecmascript-function-objects
Environment* m_environment { nullptr }; // [[Environment]]

56
Userland/Libraries/LibJS/Runtime/VM.cpp
View file

@ -525,62 +525,6 @@ Value VM::get_new_target()
return verify_cast<FunctionEnvironment>(env).new_target();
}
// 10.2.1.1 PrepareForOrdinaryCall ( F, newTarget ), https://tc39.es/ecma262/#sec-prepareforordinarycall
void VM::prepare_for_ordinary_call(FunctionObject& function, ExecutionContext& callee_context, Object* new_target)
{
// Non-standard
callee_context.is_strict_mode = function.is_strict_mode();
// 1. Let callerContext be the running execution context.
// 2. Let calleeContext be a new ECMAScript code execution context.
// NOTE: In the specification, PrepareForOrdinaryCall "returns" a new callee execution context.
// To avoid heap allocations, we put our ExecutionContext objects on the C++ stack instead.
// Whoever calls us should put an ExecutionContext on their stack and pass that as the `callee_context`.
// 3. Set the Function of calleeContext to F.
callee_context.function = &function;
callee_context.function_name = function.name();
// 4. Let calleeRealm be F.[[Realm]].
auto* callee_realm = function.realm();
// NOTE: This non-standard fallback is needed until we can guarantee that literally
// every function has a realm - especially in LibWeb that's sometimes not the case
// when a function is created while no JS is running, as we currently need to rely on
// that (:acid2:, I know - see set_event_handler_attribute() for an example).
// If there's no 'current realm' either, we can't continue and crash.
if (!callee_realm)
callee_realm = vm.current_realm();
VERIFY(callee_realm);
// 5. Set the Realm of calleeContext to calleeRealm.
callee_context.realm = callee_realm;
// 6. Set the ScriptOrModule of calleeContext to F.[[ScriptOrModule]].
// FIXME: Our execution context struct currently does not track this item.
// 7. Let localEnv be NewFunctionEnvironment(F, newTarget).
auto* local_environment = function.new_function_environment(new_target);
// 8. Set the LexicalEnvironment of calleeContext to localEnv.
callee_context.lexical_environment = local_environment;
// 9. Set the VariableEnvironment of calleeContext to localEnv.
callee_context.variable_environment = local_environment;
// 10. Set the PrivateEnvironment of calleeContext to F.[[PrivateEnvironment]].
// FIXME: We currently don't support private environments.
// 11. If callerContext is not already suspended, suspend callerContext.
// FIXME: We don't have this concept yet.
// 12. Push calleeContext onto the execution context stack; calleeContext is now the running execution context.
push_execution_context(callee_context, function.global_object());
// 13. NOTE: Any exception objects produced after this point are associated with calleeRealm.
// 14. Return calleeContext. (See NOTE above about how contexts are allocated on the C++ stack.)
}
// 10.2.1.2 OrdinaryCallBindThis ( F, calleeContext, thisArgument ), https://tc39.es/ecma262/#sec-ordinarycallbindthis
void VM::ordinary_call_bind_this(FunctionObject& function, ExecutionContext& callee_context, Value this_argument)
{

1
Userland/Libraries/LibJS/Runtime/VM.h
View file

@ -275,7 +275,6 @@ public:
void restore_execution_context_stack();
// TODO: Move these elsewhere once only used for ECMAScriptFunctionObject.
void prepare_for_ordinary_call(FunctionObject&, ExecutionContext& callee_context, Object* new_target);
void ordinary_call_bind_this(FunctionObject&, ExecutionContext&, Value this_argument);
private: