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ladybird/Userland/Libraries/LibJS/Interpreter.cpp

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LibJS: Start building a JavaScript engine for SerenityOS :^) I always tell people to start building things by working on the thing that seems the most interesting right now. The most interesting thing here was an AST + simple interpreter, so that's where we start! There is no lexer or parser yet, we build an AST directly and then execute it in the interpreter, producing a return value. This seems like the start of something interesting. :^)
2020-03-07 19:42:11 +01:00
/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
LibJS: Ensure function declarations don't leak outside function scopes When using VM::set_variable() to put the created ScriptFunction onto a ScopeObject, we would previously unexpectedly reach the global object as set_variable() checks each traversed scope for an existing Variable with the given name - which would cause a leak of the inner function past the outer function (we even had a test expecting that behaviour!). Now we first declare functions (as DeclarationKind::Var) before setting them. This will need some more work to make hoisting across non-lexical scopes work, but it fixes this specific issue for now. Fixes #6766.
2021-05-13 23:58:45 +01:00
* Copyright (c) 2020-2021, Linus Groh <linusg@serenityos.org>
LibJS: Refactor interpreter to use Script and Source Text Modules This also refactors interpreter creation to follow InitializeHostDefinedRealm, but I couldn't fit it in the title :^) This allows us to follow the spec much more closely rather than being completely ad-hoc with just the parse node instead of having all the surrounding data such as the realm of the parse node. The interpreter creation refactor creates the global execution context once and doesn't take it off the stack. This allows LibWeb to take the global execution context and manually handle it, following the HTML spec. The HTML spec calls this the "realm execution context" of the environment settings object. It also allows us to specify the globalThis type, as it can be different from the global object type. For example, on the web, Window global objects use a WindowProxy global this value to enforce the same origin policy on operations like [[GetOwnProperty]]. Finally, it allows us to directly call Program::execute in perform_eval and perform_shadow_realm_eval as this moves global_declaration_instantiation into Interpreter::run (ScriptEvaluation) as per the spec. Note that this doesn't evalulate Source Text Modules yet or refactor the bytecode interpreter, that's work for future us :^) This patch was originally build by Luke for the environment settings object change but was also needed for modules. So I (davidot) have modified it with the new completion changes and setup for that. Co-authored-by: davidot <davidot@serenityos.org>
2022-01-16 13:16:04 +01:00
* Copyright (c) 2022, Luke Wilde <lukew@serenityos.org>
LibJS: Start building a JavaScript engine for SerenityOS :^) I always tell people to start building things by working on the thing that seems the most interesting right now. The most interesting thing here was an AST + simple interpreter, so that's where we start! There is no lexer or parser yet, we build an AST directly and then execute it in the interpreter, producing a return value. This seems like the start of something interesting. :^)
2020-03-07 19:42:11 +01:00
*
Everything: Move to SPDX license identifiers in all files. SPDX License Identifiers are a more compact / standardized way of representing file license information. See: https://spdx.dev/resources/use/#identifiers This was done with the `ambr` search and replace tool. ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
2021-04-22 01:24:48 -07:00
* SPDX-License-Identifier: BSD-2-Clause
LibJS: Start building a JavaScript engine for SerenityOS :^) I always tell people to start building things by working on the thing that seems the most interesting right now. The most interesting thing here was an AST + simple interpreter, so that's where we start! There is no lexer or parser yet, we build an AST directly and then execute it in the interpreter, producing a return value. This seems like the start of something interesting. :^)
2020-03-07 19:42:11 +01:00
*/
LibJS: Ensure function declarations don't leak outside function scopes When using VM::set_variable() to put the created ScriptFunction onto a ScopeObject, we would previously unexpectedly reach the global object as set_variable() checks each traversed scope for an existing Variable with the given name - which would cause a leak of the inner function past the outer function (we even had a test expecting that behaviour!). Now we first declare functions (as DeclarationKind::Var) before setting them. This will need some more work to make hoisting across non-lexical scopes work, but it fixes this specific issue for now. Fixes #6766.
2021-05-13 23:58:45 +01:00
#include <AK/ScopeGuard.h>
LibJS: Start building a JavaScript engine for SerenityOS :^) I always tell people to start building things by working on the thing that seems the most interesting right now. The most interesting thing here was an AST + simple interpreter, so that's where we start! There is no lexer or parser yet, we build an AST directly and then execute it in the interpreter, producing a return value. This seems like the start of something interesting. :^)
2020-03-07 19:42:11 +01:00
#include <LibJS/AST.h>
#include <LibJS/Interpreter.h>
LibJS: Make scoping follow the spec Before this we used an ad-hoc combination of references and 'variables' stored in a hashmap. This worked in most cases but is not spec like. Additionally hoisting, dynamically naming functions and scope analysis was not done properly. This patch fixes all of that by: - Implement BindingInitialization for destructuring assignment. - Implementing a new ScopePusher which tracks the lexical and var scoped declarations. This hoists functions to the top level if no lexical declaration name overlaps. Furthermore we do checking of redeclarations in the ScopePusher now requiring less checks all over the place. - Add methods for parsing the directives and statement lists instead of having that code duplicated in multiple places. This allows declarations to pushed to the appropriate scope more easily. - Remove the non spec way of storing 'variables' in DeclarativeEnvironment and make Reference follow the spec instead of checking both the bindings and 'variables'. - Remove all scoping related things from the Interpreter. And instead use environments as specified by the spec. This also includes fixing that NativeFunctions did not produce a valid FunctionEnvironment which could cause issues with callbacks and eval. All FunctionObjects now have a valid NewFunctionEnvironment implementation. - Remove execute_statements from Interpreter and instead use ASTNode::execute everywhere this simplifies AST.cpp as you no longer need to worry about which method to call. - Make ScopeNodes setup their own environment. This uses four different methods specified by the spec {Block, Function, Eval, Global}DeclarationInstantiation with the annexB extensions. - Implement and use NamedEvaluation where specified. Additionally there are fixes to things exposed by these changes to eval, {for, for-in, for-of} loops and assignment. Finally it also fixes some tests in test-js which where passing before but not now that we have correct behavior :^).
2021-09-22 12:44:56 +02:00
#include <LibJS/Runtime/AbstractOperations.h>
LibJS: Rename OrdinaryFunctionObject to ECMAScriptFunctionObject The old name is the result of the perhaps somewhat confusingly named abstract operation OrdinaryFunctionCreate(), which creates an "ordinary object" (https://tc39.es/ecma262/#ordinary-object) in contrast to an "exotic object" (https://tc39.es/ecma262/#exotic-object). However, the term "Ordinary Function" is not used anywhere in the spec, instead the created object is referred to as an "ECMAScript Function Object" (https://tc39.es/ecma262/#sec-ecmascript-function-objects), so let's call it that. The "ordinary" vs. "exotic" distinction is important because there are also "Built-in Function Objects", which can be either implemented as ordinary ECMAScript function objects, or as exotic objects (our NativeFunction). More work needs to be done to move a lot of infrastructure to ECMAScriptFunctionObject in order to make FunctionObject nothing more than an interface for objects that implement [[Call]] and optionally [[Construct]].
2021-09-24 22:40:38 +02:00
#include <LibJS/Runtime/ECMAScriptFunctionObject.h>
LibJS: Drop "Record" suffix from all the *Environment record classes "Records" in the spec are basically C++ classes, so let's drop this mouthful of a suffix.
2021-07-01 12:24:46 +02:00
#include <LibJS/Runtime/FunctionEnvironment.h>
#include <LibJS/Runtime/GlobalEnvironment.h>
LibJS: Add "Heap" and "Runtime" subdirectories Let's try to keep LibJS tidy as it expands. :^)
2020-03-16 14:20:30 +01:00
#include <LibJS/Runtime/GlobalObject.h>
LibJS: Allow "delete someGlobalVariable" This is solved by allowing Identifier nodes to produce a Reference with the global object as base.
2020-04-27 12:37:27 +02:00
#include <LibJS/Runtime/Reference.h>
LibJS: Start implementing object shapes This patch adds JS::Shape, which implements a transition tree for our Object class. Object property keys, prototypes and attributes are now stored in a Shape, and each Object has a Shape. When adding a property to an Object, we make a transition from the old Shape to a new Shape. If we've made the same exact transition in the past (with another Object), we reuse the same transition and both objects may now share a Shape. This will become the foundation of inline caching and other engine optimizations in the future. :^)
2020-04-02 19:32:21 +02:00
#include <LibJS/Runtime/Shape.h>
LibJS: Add "Heap" and "Runtime" subdirectories Let's try to keep LibJS tidy as it expands. :^)
2020-03-16 14:20:30 +01:00
#include <LibJS/Runtime/Value.h>
LibJS: Start building a JavaScript engine for SerenityOS :^) I always tell people to start building things by working on the thing that seems the most interesting right now. The most interesting thing here was an AST + simple interpreter, so that's where we start! There is no lexer or parser yet, we build an AST directly and then execute it in the interpreter, producing a return value. This seems like the start of something interesting. :^)
2020-03-07 19:42:11 +01:00
namespace JS {
LibJS: Change Interpreter::create_with_existing_{global_object => realm} We need both a GlobalObject and Realm now, but can get the former from the latter (once initialized). This also fixes JS execution in LibWeb, as we failed to set the Realm of the newly created Interpreter in this function.
2021-09-12 12:33:54 +01:00
NonnullOwnPtr<Interpreter> Interpreter::create_with_existing_realm(Realm& realm)
LibJS: Make Function::call() not require an Interpreter& This makes a difference inside ScriptFunction::call(), which will now instantiate a temporary Interpreter if one is not attached to the VM.
2020-09-27 17:24:14 +02:00
{
LibJS: Change Interpreter::create_with_existing_{global_object => realm} We need both a GlobalObject and Realm now, but can get the former from the latter (once initialized). This also fixes JS execution in LibWeb, as we failed to set the Realm of the newly created Interpreter in this function.
2021-09-12 12:33:54 +01:00
auto& global_object = realm.global_object();
LibJS: Make Function::call() not require an Interpreter& This makes a difference inside ScriptFunction::call(), which will now instantiate a temporary Interpreter if one is not attached to the VM.
2020-09-27 17:24:14 +02:00
DeferGC defer_gc(global_object.heap());
auto interpreter = adopt_own(*new Interpreter(global_object.vm()));
LibJS: Allocate a Realm next to GlobalObject in Interpreter::create() Also pass a Realm reference to the Bytecode::Interpreter constructor, just like we pass the GlobalObject.
2021-09-11 19:36:25 +01:00
interpreter->m_global_object = make_handle(&global_object);
LibJS: Change Interpreter::create_with_existing_{global_object => realm} We need both a GlobalObject and Realm now, but can get the former from the latter (once initialized). This also fixes JS execution in LibWeb, as we failed to set the Realm of the newly created Interpreter in this function.
2021-09-12 12:33:54 +01:00
interpreter->m_realm = make_handle(&realm);
LibJS: Make Function::call() not require an Interpreter& This makes a difference inside ScriptFunction::call(), which will now instantiate a temporary Interpreter if one is not attached to the VM.
2020-09-27 17:24:14 +02:00
return interpreter;
}
LibJS+Clients: Add JS::VM object, separate Heap from Interpreter Taking a big step towards a world of multiple global object, this patch adds a new JS::VM object that houses the JS::Heap. This means that the Heap moves out of Interpreter, and the same Heap can now be used by multiple Interpreters, and can also outlive them. The VM keeps a stack of Interpreter pointers. We push/pop on this stack when entering/exiting execution with a given Interpreter. This allows us to make this change without disturbing too much of the existing code. There is still a 1-to-1 relationship between Interpreter and the global object. This will change in the future. Ultimately, the goal here is to make Interpreter a transient object that only needs to exist while you execute some code. Getting there will take a lot more work though. :^) Note that in LibWeb, the global JS::VM is called main_thread_vm(), to distinguish it from future worker VM's.
2020-09-20 19:24:44 +02:00
Interpreter::Interpreter(VM& vm)
: m_vm(vm)
LibJS: Refactor interpreter to use Script and Source Text Modules This also refactors interpreter creation to follow InitializeHostDefinedRealm, but I couldn't fit it in the title :^) This allows us to follow the spec much more closely rather than being completely ad-hoc with just the parse node instead of having all the surrounding data such as the realm of the parse node. The interpreter creation refactor creates the global execution context once and doesn't take it off the stack. This allows LibWeb to take the global execution context and manually handle it, following the HTML spec. The HTML spec calls this the "realm execution context" of the environment settings object. It also allows us to specify the globalThis type, as it can be different from the global object type. For example, on the web, Window global objects use a WindowProxy global this value to enforce the same origin policy on operations like [[GetOwnProperty]]. Finally, it allows us to directly call Program::execute in perform_eval and perform_shadow_realm_eval as this moves global_declaration_instantiation into Interpreter::run (ScriptEvaluation) as per the spec. Note that this doesn't evalulate Source Text Modules yet or refactor the bytecode interpreter, that's work for future us :^) This patch was originally build by Luke for the environment settings object change but was also needed for modules. So I (davidot) have modified it with the new completion changes and setup for that. Co-authored-by: davidot <davidot@serenityos.org>
2022-01-16 13:16:04 +01:00
, m_global_execution_context(vm.heap())
LibJS: Start building a JavaScript engine for SerenityOS :^) I always tell people to start building things by working on the thing that seems the most interesting right now. The most interesting thing here was an AST + simple interpreter, so that's where we start! There is no lexer or parser yet, we build an AST directly and then execute it in the interpreter, producing a return value. This seems like the start of something interesting. :^)
2020-03-07 19:42:11 +01:00
{
}
LibJS: Refactor interpreter to use Script and Source Text Modules This also refactors interpreter creation to follow InitializeHostDefinedRealm, but I couldn't fit it in the title :^) This allows us to follow the spec much more closely rather than being completely ad-hoc with just the parse node instead of having all the surrounding data such as the realm of the parse node. The interpreter creation refactor creates the global execution context once and doesn't take it off the stack. This allows LibWeb to take the global execution context and manually handle it, following the HTML spec. The HTML spec calls this the "realm execution context" of the environment settings object. It also allows us to specify the globalThis type, as it can be different from the global object type. For example, on the web, Window global objects use a WindowProxy global this value to enforce the same origin policy on operations like [[GetOwnProperty]]. Finally, it allows us to directly call Program::execute in perform_eval and perform_shadow_realm_eval as this moves global_declaration_instantiation into Interpreter::run (ScriptEvaluation) as per the spec. Note that this doesn't evalulate Source Text Modules yet or refactor the bytecode interpreter, that's work for future us :^) This patch was originally build by Luke for the environment settings object change but was also needed for modules. So I (davidot) have modified it with the new completion changes and setup for that. Co-authored-by: davidot <davidot@serenityos.org>
2022-01-16 13:16:04 +01:00
// 16.1.6 ScriptEvaluation ( scriptRecord ), https://tc39.es/ecma262/#sec-runtime-semantics-scriptevaluation
ThrowCompletionOr<Value> Interpreter::run(Script& script_record)
LibJS: Start building a JavaScript engine for SerenityOS :^) I always tell people to start building things by working on the thing that seems the most interesting right now. The most interesting thing here was an AST + simple interpreter, so that's where we start! There is no lexer or parser yet, we build an AST directly and then execute it in the interpreter, producing a return value. This seems like the start of something interesting. :^)
2020-03-07 19:42:11 +01:00
{
LibJS: Throw RuntimeError when reaching the end of the stack This prevents stack overflows when calling infinite/deep recursive functions, e.g.: const f = () => f(); f(); JSON.stringify({}, () => ({ foo: "bar" })); new Proxy({}, { get: (_, __, p) => p.foo }).foo; The VM caches a StackInfo object to not slow down function calls considerably. VM::push_call_frame() will throw an exception if necessary (plain Error with "RuntimeError" as its .name).
2020-11-08 12:54:52 +00:00
auto& vm = this->vm();
LibJS: Hoist variable declarations to the nearest relevant scope "var" declarations are hoisted to the nearest function scope, while "let" and "const" are hoisted to the nearest block scope. This is done by the parser, which keeps two scope stacks, one stack for the current var scope and one for the current let/const scope. When the interpreter enters a scope, we walk all of the declarations and insert them into the variable environment. We don't support the temporal dead zone for let/const yet.
2020-04-13 16:42:54 +02:00
LibJS: Move most of Interpreter into VM This patch moves the exception state, call stack and scope stack from Interpreter to VM. I'm doing this to help myself discover what the split between Interpreter and VM should be, by shuffling things around and seeing what falls where. With these changes, we no longer have a persistent lexical environment for the current global object on the Interpreter's call stack. Instead, we push/pop that environment on Interpreter::run() enter/exit. Since it should only be used to find the global "this", and not for variable storage (that goes directly into the global object instead!), I had to insert some short-circuiting when walking the environment parent chain during variable lookup. Note that this is a "stepping stone" commit, not a final design.
2020-09-27 15:18:55 +02:00
VM::InterpreterExecutionScope scope(*this);
LibJS: Add basic support for (scoped) variables It's now possible to assign expressions to variables. The variables are put into the current scope of the interpreter. Variable lookup follows the scope chain, ending in the global object.
2020-03-09 21:13:55 +01:00
LibJS: Refactor interpreter to use Script and Source Text Modules This also refactors interpreter creation to follow InitializeHostDefinedRealm, but I couldn't fit it in the title :^) This allows us to follow the spec much more closely rather than being completely ad-hoc with just the parse node instead of having all the surrounding data such as the realm of the parse node. The interpreter creation refactor creates the global execution context once and doesn't take it off the stack. This allows LibWeb to take the global execution context and manually handle it, following the HTML spec. The HTML spec calls this the "realm execution context" of the environment settings object. It also allows us to specify the globalThis type, as it can be different from the global object type. For example, on the web, Window global objects use a WindowProxy global this value to enforce the same origin policy on operations like [[GetOwnProperty]]. Finally, it allows us to directly call Program::execute in perform_eval and perform_shadow_realm_eval as this moves global_declaration_instantiation into Interpreter::run (ScriptEvaluation) as per the spec. Note that this doesn't evalulate Source Text Modules yet or refactor the bytecode interpreter, that's work for future us :^) This patch was originally build by Luke for the environment settings object change but was also needed for modules. So I (davidot) have modified it with the new completion changes and setup for that. Co-authored-by: davidot <davidot@serenityos.org>
2022-01-16 13:16:04 +01:00
// 1. Let globalEnv be scriptRecord.[[Realm]].[[GlobalEnv]].
auto& global_environment = script_record.realm().global_environment();
// NOTE: This isn't in the spec but we require it.
auto& global_object = script_record.realm().global_object();
// 2. Let scriptContext be a new ECMAScript code execution context.
ExecutionContext script_context(vm.heap());
// 3. Set the Function of scriptContext to null. (This was done in the construction of script_context)
// 4. Set the Realm of scriptContext to scriptRecord.[[Realm]].
script_context.realm = &script_record.realm();
LibJS: Add ScriptOrModule to execution context and track it everywhere
2022-01-17 14:48:22 +01:00
// 5. Set the ScriptOrModule of scriptContext to scriptRecord.
LibJS: Make ScriptOrModule use WeakPtr instead of raw pointers
2022-02-07 16:28:39 +01:00
script_context.script_or_module = script_record.make_weak_ptr();
LibJS: Refactor interpreter to use Script and Source Text Modules This also refactors interpreter creation to follow InitializeHostDefinedRealm, but I couldn't fit it in the title :^) This allows us to follow the spec much more closely rather than being completely ad-hoc with just the parse node instead of having all the surrounding data such as the realm of the parse node. The interpreter creation refactor creates the global execution context once and doesn't take it off the stack. This allows LibWeb to take the global execution context and manually handle it, following the HTML spec. The HTML spec calls this the "realm execution context" of the environment settings object. It also allows us to specify the globalThis type, as it can be different from the global object type. For example, on the web, Window global objects use a WindowProxy global this value to enforce the same origin policy on operations like [[GetOwnProperty]]. Finally, it allows us to directly call Program::execute in perform_eval and perform_shadow_realm_eval as this moves global_declaration_instantiation into Interpreter::run (ScriptEvaluation) as per the spec. Note that this doesn't evalulate Source Text Modules yet or refactor the bytecode interpreter, that's work for future us :^) This patch was originally build by Luke for the environment settings object change but was also needed for modules. So I (davidot) have modified it with the new completion changes and setup for that. Co-authored-by: davidot <davidot@serenityos.org>
2022-01-16 13:16:04 +01:00
// 6. Set the VariableEnvironment of scriptContext to globalEnv.
script_context.variable_environment = &global_environment;
// 7. Set the LexicalEnvironment of scriptContext to globalEnv.
script_context.lexical_environment = &global_environment;
// 8. Set the PrivateEnvironment of scriptContext to null.
// NOTE: This isn't in the spec, but we require it.
script_context.is_strict_mode = script_record.parse_node().is_strict_mode();
// FIXME: 9. Suspend the currently running execution context.
// 10. Push scriptContext onto the execution context stack; scriptContext is now the running execution context.
LibJS: Use TRY(push_execution_context()) in places where we can recover
2022-03-17 22:42:41 +00:00
TRY(vm.push_execution_context(script_context, global_object));
LibJS: Refactor interpreter to use Script and Source Text Modules This also refactors interpreter creation to follow InitializeHostDefinedRealm, but I couldn't fit it in the title :^) This allows us to follow the spec much more closely rather than being completely ad-hoc with just the parse node instead of having all the surrounding data such as the realm of the parse node. The interpreter creation refactor creates the global execution context once and doesn't take it off the stack. This allows LibWeb to take the global execution context and manually handle it, following the HTML spec. The HTML spec calls this the "realm execution context" of the environment settings object. It also allows us to specify the globalThis type, as it can be different from the global object type. For example, on the web, Window global objects use a WindowProxy global this value to enforce the same origin policy on operations like [[GetOwnProperty]]. Finally, it allows us to directly call Program::execute in perform_eval and perform_shadow_realm_eval as this moves global_declaration_instantiation into Interpreter::run (ScriptEvaluation) as per the spec. Note that this doesn't evalulate Source Text Modules yet or refactor the bytecode interpreter, that's work for future us :^) This patch was originally build by Luke for the environment settings object change but was also needed for modules. So I (davidot) have modified it with the new completion changes and setup for that. Co-authored-by: davidot <davidot@serenityos.org>
2022-01-16 13:16:04 +01:00
// 11. Let scriptBody be scriptRecord.[[ECMAScriptCode]].
auto& script_body = script_record.parse_node();
// 12. Let result be GlobalDeclarationInstantiation(scriptBody, globalEnv).
auto instantiation_result = script_body.global_declaration_instantiation(*this, global_object, global_environment);
Completion result = instantiation_result.is_throw_completion() ? instantiation_result.throw_completion() : normal_completion({});
// 13. If result.[[Type]] is normal, then
if (result.type() == Completion::Type::Normal) {
// a. Set result to the result of evaluating scriptBody.
result = script_body.execute(*this, global_object);
}
// 14. If result.[[Type]] is normal and result.[[Value]] is empty, then
if (result.type() == Completion::Type::Normal && !result.value().has_value()) {
// a. Set result to NormalCompletion(undefined).
result = normal_completion(js_undefined());
}
// FIXME: 15. Suspend scriptContext and remove it from the execution context stack.
vm.pop_execution_context();
// 16. Assert: The execution context stack is not empty.
VERIFY(!vm.execution_context_stack().is_empty());
// FIXME: 17. Resume the context that is now on the top of the execution context stack as the running execution context.
LibJS: Add VM::on_call_stack_emptied callback Instead of having to run queued promise jobs in LibWeb in various places, this allows us to consolidate that into one function - this is very close to how the spec describes it as well ("at some future point in time, when there is no running execution context and the execution context stack is empty, the implementation must [...]"). Eventually this will also be used to log unhandled exceptions, and possibly other actions that require JS execution to have ended.
2021-04-24 18:21:02 +02:00
// At this point we may have already run any queued promise jobs via on_call_stack_emptied,
// in which case this is a no-op.
LibJS: Refactor interpreter to use Script and Source Text Modules This also refactors interpreter creation to follow InitializeHostDefinedRealm, but I couldn't fit it in the title :^) This allows us to follow the spec much more closely rather than being completely ad-hoc with just the parse node instead of having all the surrounding data such as the realm of the parse node. The interpreter creation refactor creates the global execution context once and doesn't take it off the stack. This allows LibWeb to take the global execution context and manually handle it, following the HTML spec. The HTML spec calls this the "realm execution context" of the environment settings object. It also allows us to specify the globalThis type, as it can be different from the global object type. For example, on the web, Window global objects use a WindowProxy global this value to enforce the same origin policy on operations like [[GetOwnProperty]]. Finally, it allows us to directly call Program::execute in perform_eval and perform_shadow_realm_eval as this moves global_declaration_instantiation into Interpreter::run (ScriptEvaluation) as per the spec. Note that this doesn't evalulate Source Text Modules yet or refactor the bytecode interpreter, that's work for future us :^) This patch was originally build by Luke for the environment settings object change but was also needed for modules. So I (davidot) have modified it with the new completion changes and setup for that. Co-authored-by: davidot <davidot@serenityos.org>
2022-01-16 13:16:04 +01:00
// FIXME: These three should be moved out of Interpreter::run and give the host an option to run these, as it's up to the host when these get run.
// https://tc39.es/ecma262/#sec-jobs for jobs and https://tc39.es/ecma262/#_ref_3508 for ClearKeptObjects
// finish_execution_generation is particularly an issue for LibWeb, as the HTML spec wants to run it specifically after performing a microtask checkpoint.
// The promise and registry cleanup queues don't cause LibWeb an issue, as LibWeb overrides the hooks that push onto these queues.
LibJS: Add initial support for Promises Almost a year after first working on this, it's finally done: an implementation of Promises for LibJS! :^) The core functionality is working and closely following the spec [1]. I mostly took the pseudo code and transformed it into C++ - if you read and understand it, you will know how the spec implements Promises; and if you read the spec first, the code will look very familiar. Implemented functions are: - Promise() constructor - Promise.prototype.then() - Promise.prototype.catch() - Promise.prototype.finally() - Promise.resolve() - Promise.reject() For the tests I added a new function to test-js's global object, runQueuedPromiseJobs(), which calls vm.run_queued_promise_jobs(). By design, queued jobs normally only run after the script was fully executed, making it improssible to test handlers in individual test() calls by default [2]. Subsequent commits include integrations into LibWeb and js(1) - pretty-printing, running queued promise jobs when necessary. This has an unusual amount of dbgln() statements, all hidden behind the PROMISE_DEBUG flag - I'm leaving them in for now as they've been very useful while debugging this, things can get quite complex with so many asynchronously executed functions. I've not extensively explored use of these APIs for promise-based functionality in LibWeb (fetch(), Notification.requestPermission() etc.), but we'll get there in due time. [1]: https://tc39.es/ecma262/#sec-promise-objects [2]: https://tc39.es/ecma262/#sec-jobs-and-job-queues
2021-04-01 22:13:29 +02:00
vm.run_queued_promise_jobs();
LibJS: Store and maintain an "execution generation" counter This counter is increased each time a synchronous execution sequence completes, and will allow us to emulate the abstract operations AddToKeptObjects & ClearKeptObjects efficiently.
2021-06-12 17:32:54 +03:00
LibJS: Add the FinalizationRegistry built-in object As well as the needed functionality in VM to enqueue and run cleanup jobs for the FinalizationRegistry instances.
2021-06-15 22:16:17 +03:00
vm.run_queued_finalization_registry_cleanup_jobs();
LibJS: Store and maintain an "execution generation" counter This counter is increased each time a synchronous execution sequence completes, and will allow us to emulate the abstract operations AddToKeptObjects & ClearKeptObjects efficiently.
2021-06-12 17:32:54 +03:00
vm.finish_execution_generation();
LibJS: Convert Interpreter::run() to ThrowCompletionOr<Value> Instead of making it a void function, checking for an exception, and then receiving the relevant result via VM::last_value(), we can consolidate all of this by using completions. This allows us to remove more uses of VM::exception(), and all uses of VM::last_value().
2022-01-08 21:28:27 +01:00
LibJS: Refactor interpreter to use Script and Source Text Modules This also refactors interpreter creation to follow InitializeHostDefinedRealm, but I couldn't fit it in the title :^) This allows us to follow the spec much more closely rather than being completely ad-hoc with just the parse node instead of having all the surrounding data such as the realm of the parse node. The interpreter creation refactor creates the global execution context once and doesn't take it off the stack. This allows LibWeb to take the global execution context and manually handle it, following the HTML spec. The HTML spec calls this the "realm execution context" of the environment settings object. It also allows us to specify the globalThis type, as it can be different from the global object type. For example, on the web, Window global objects use a WindowProxy global this value to enforce the same origin policy on operations like [[GetOwnProperty]]. Finally, it allows us to directly call Program::execute in perform_eval and perform_shadow_realm_eval as this moves global_declaration_instantiation into Interpreter::run (ScriptEvaluation) as per the spec. Note that this doesn't evalulate Source Text Modules yet or refactor the bytecode interpreter, that's work for future us :^) This patch was originally build by Luke for the environment settings object change but was also needed for modules. So I (davidot) have modified it with the new completion changes and setup for that. Co-authored-by: davidot <davidot@serenityos.org>
2022-01-16 13:16:04 +01:00
// 18. Return Completion(result).
if (result.is_abrupt()) {
VERIFY(result.type() == Completion::Type::Throw);
return result.release_error();
LibJS: Convert Interpreter::run() to ThrowCompletionOr<Value> Instead of making it a void function, checking for an exception, and then receiving the relevant result via VM::last_value(), we can consolidate all of this by using completions. This allows us to remove more uses of VM::exception(), and all uses of VM::last_value().
2022-01-08 21:28:27 +01:00
}
LibJS: Refactor interpreter to use Script and Source Text Modules This also refactors interpreter creation to follow InitializeHostDefinedRealm, but I couldn't fit it in the title :^) This allows us to follow the spec much more closely rather than being completely ad-hoc with just the parse node instead of having all the surrounding data such as the realm of the parse node. The interpreter creation refactor creates the global execution context once and doesn't take it off the stack. This allows LibWeb to take the global execution context and manually handle it, following the HTML spec. The HTML spec calls this the "realm execution context" of the environment settings object. It also allows us to specify the globalThis type, as it can be different from the global object type. For example, on the web, Window global objects use a WindowProxy global this value to enforce the same origin policy on operations like [[GetOwnProperty]]. Finally, it allows us to directly call Program::execute in perform_eval and perform_shadow_realm_eval as this moves global_declaration_instantiation into Interpreter::run (ScriptEvaluation) as per the spec. Note that this doesn't evalulate Source Text Modules yet or refactor the bytecode interpreter, that's work for future us :^) This patch was originally build by Luke for the environment settings object change but was also needed for modules. So I (davidot) have modified it with the new completion changes and setup for that. Co-authored-by: davidot <davidot@serenityos.org>
2022-01-16 13:16:04 +01:00
VERIFY(result.value().has_value());
return *result.value();
}
LibJS: Implement HostResolveImportedModule for LibJS This loads modules with relative paths from the referencing module. In this commit the only way to run a module is via the interpreter which can link and evaluate a module (and all its dependencies).
2022-01-19 01:22:58 +01:00
ThrowCompletionOr<Value> Interpreter::run(SourceTextModule& module)
LibJS: Refactor interpreter to use Script and Source Text Modules This also refactors interpreter creation to follow InitializeHostDefinedRealm, but I couldn't fit it in the title :^) This allows us to follow the spec much more closely rather than being completely ad-hoc with just the parse node instead of having all the surrounding data such as the realm of the parse node. The interpreter creation refactor creates the global execution context once and doesn't take it off the stack. This allows LibWeb to take the global execution context and manually handle it, following the HTML spec. The HTML spec calls this the "realm execution context" of the environment settings object. It also allows us to specify the globalThis type, as it can be different from the global object type. For example, on the web, Window global objects use a WindowProxy global this value to enforce the same origin policy on operations like [[GetOwnProperty]]. Finally, it allows us to directly call Program::execute in perform_eval and perform_shadow_realm_eval as this moves global_declaration_instantiation into Interpreter::run (ScriptEvaluation) as per the spec. Note that this doesn't evalulate Source Text Modules yet or refactor the bytecode interpreter, that's work for future us :^) This patch was originally build by Luke for the environment settings object change but was also needed for modules. So I (davidot) have modified it with the new completion changes and setup for that. Co-authored-by: davidot <davidot@serenityos.org>
2022-01-16 13:16:04 +01:00
{
LibJS: Implement HostResolveImportedModule for LibJS This loads modules with relative paths from the referencing module. In this commit the only way to run a module is via the interpreter which can link and evaluate a module (and all its dependencies).
2022-01-19 01:22:58 +01:00
// FIXME: This is not a entry point as defined in the spec, but is convenient.
// To avoid work we use link_and_eval_module however that can already be
// dangerous if the vm loaded other modules.
auto& vm = this->vm();
VM::InterpreterExecutionScope scope(*this);
LibJS+Everywhere: Remove VM::exception() and most related functions This commit removes all exception related code: Remove VM::exception(), VM::throw_exception() etc. Any leftover throw_exception calls are moved to throw_completion. The one method left is clear_exception() which is now a no-op. Most of these calls are just to clear whatever exception might have been thrown when handling a Completion. So to have a cleaner commit this will be removed in a next commit. It also removes the actual Exception and TemporaryClearException classes since these are no longer used. In any spot where the exception was actually used an attempt was made to preserve that behavior. However since it is no longer tracked by the VM we cannot access exceptions which were thrown in previous calls. There are two such cases which might have different behavior: - In Web::DOM::Document::interpreter() the on_call_stack_emptied hook used to print any uncaught exception but this is now no longer possible as the VM does not store uncaught exceptions. - In js the code used to be interruptable by throwing an exception on the VM. This is no longer possible but was already somewhat fragile before as you could happen to throw an exception just before a VERIFY.
2022-02-07 15:12:41 +01:00
TRY(vm.link_and_eval_module({}, module));
LibJS: Implement HostResolveImportedModule for LibJS This loads modules with relative paths from the referencing module. In this commit the only way to run a module is via the interpreter which can link and evaluate a module (and all its dependencies).
2022-01-19 01:22:58 +01:00
vm.run_queued_promise_jobs();
vm.run_queued_finalization_registry_cleanup_jobs();
return js_undefined();
LibJS: Add basic support for (scoped) variables It's now possible to assign expressions to variables. The variables are put into the current scope of the interpreter. Variable lookup follows the scope chain, ending in the global object.
2020-03-09 21:13:55 +01:00
}
LibJS: Move most of Interpreter into VM This patch moves the exception state, call stack and scope stack from Interpreter to VM. I'm doing this to help myself discover what the split between Interpreter and VM should be, by shuffling things around and seeing what falls where. With these changes, we no longer have a persistent lexical environment for the current global object on the Interpreter's call stack. Instead, we push/pop that environment on Interpreter::run() enter/exit. Since it should only be used to find the global "this", and not for variable storage (that goes directly into the global object instead!), I had to insert some short-circuiting when walking the environment parent chain during variable lookup. Note that this is a "stepping stone" commit, not a final design.
2020-09-27 15:18:55 +02:00
GlobalObject& Interpreter::global_object()
LibJS: Allow "delete someGlobalVariable" This is solved by allowing Identifier nodes to produce a Reference with the global object as base.
2020-04-27 12:37:27 +02:00
{
LibJS: Move most of Interpreter into VM This patch moves the exception state, call stack and scope stack from Interpreter to VM. I'm doing this to help myself discover what the split between Interpreter and VM should be, by shuffling things around and seeing what falls where. With these changes, we no longer have a persistent lexical environment for the current global object on the Interpreter's call stack. Instead, we push/pop that environment on Interpreter::run() enter/exit. Since it should only be used to find the global "this", and not for variable storage (that goes directly into the global object instead!), I had to insert some short-circuiting when walking the environment parent chain during variable lookup. Note that this is a "stepping stone" commit, not a final design.
2020-09-27 15:18:55 +02:00
return static_cast<GlobalObject&>(*m_global_object.cell());
LibJS: Allow "delete someGlobalVariable" This is solved by allowing Identifier nodes to produce a Reference with the global object as base.
2020-04-27 12:37:27 +02:00
}
LibJS: Move most of Interpreter into VM This patch moves the exception state, call stack and scope stack from Interpreter to VM. I'm doing this to help myself discover what the split between Interpreter and VM should be, by shuffling things around and seeing what falls where. With these changes, we no longer have a persistent lexical environment for the current global object on the Interpreter's call stack. Instead, we push/pop that environment on Interpreter::run() enter/exit. Since it should only be used to find the global "this", and not for variable storage (that goes directly into the global object instead!), I had to insert some short-circuiting when walking the environment parent chain during variable lookup. Note that this is a "stepping stone" commit, not a final design.
2020-09-27 15:18:55 +02:00
const GlobalObject& Interpreter::global_object() const
LibJS: Make sure we mark everything reachable from the scope stack This ensures that local variables survive GC.
2020-03-09 21:29:22 +01:00
{
LibJS: Move most of Interpreter into VM This patch moves the exception state, call stack and scope stack from Interpreter to VM. I'm doing this to help myself discover what the split between Interpreter and VM should be, by shuffling things around and seeing what falls where. With these changes, we no longer have a persistent lexical environment for the current global object on the Interpreter's call stack. Instead, we push/pop that environment on Interpreter::run() enter/exit. Since it should only be used to find the global "this", and not for variable storage (that goes directly into the global object instead!), I had to insert some short-circuiting when walking the environment parent chain during variable lookup. Note that this is a "stepping stone" commit, not a final design.
2020-09-27 15:18:55 +02:00
return static_cast<const GlobalObject&>(*m_global_object.cell());
LibJS: Make sure we mark everything reachable from the scope stack This ensures that local variables survive GC.
2020-03-09 21:29:22 +01:00
}
LibJS: Allocate a Realm next to GlobalObject in Interpreter::create() Also pass a Realm reference to the Bytecode::Interpreter constructor, just like we pass the GlobalObject.
2021-09-11 19:36:25 +01:00
Realm& Interpreter::realm()
{
return static_cast<Realm&>(*m_realm.cell());
}
const Realm& Interpreter::realm() const
{
return static_cast<const Realm&>(*m_realm.cell());
}
LibJS: Start building a JavaScript engine for SerenityOS :^) I always tell people to start building things by working on the thing that seems the most interesting right now. The most interesting thing here was an AST + simple interpreter, so that's where we start! There is no lexer or parser yet, we build an AST directly and then execute it in the interpreter, producing a return value. This seems like the start of something interesting. :^)
2020-03-07 19:42:11 +01:00
}
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