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ladybird/Userland/Libraries/LibJS/Runtime/VM.h

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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.
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/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
Everywhere: Use linusg@serenityos.org for my copyright headers
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* Copyright (c) 2020-2021, Linus Groh <linusg@serenityos.org>
Everywhere: Use my awesome new serenityos email :^)
2021-10-03 14:16:10 +02:00
* Copyright (c) 2021, David Tuin <davidot@serenityos.org>
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.
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*
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 *
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* SPDX-License-Identifier: BSD-2-Clause
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
*/
#pragma once
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
#include <AK/FlyString.h>
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
#include <AK/Function.h>
LibJS: Move well-known symbols to the VM No need to instantiate unique symbols for each Interpreter; they can be VM-global. This reduces the memory cost and startup time anyway.
2020-09-22 16:18:51 +02:00
#include <AK/HashMap.h>
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
#include <AK/RefCounted.h>
LibJS+AK: Move cross-platform stack bounds code from JS::Heap to AK::StackInfo This will be useful for other things than the Heap, maybe even outside of LibJS.
2020-11-08 12:48:16 +00:00
#include <AK/StackInfo.h>
LibJS: Implement destructuring assignments and function parameters
2021-05-29 16:03:19 +04:30
#include <AK/Variant.h>
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
#include <LibJS/Heap/Heap.h>
LibJS: Cache commonly used FlyStrings in the VM Roughly 7% of test-js runtime was spent creating FlyStrings from string literals. This patch frontloads that work and caches all the commonly used names in LibJS on a CommonPropertyNames struct that hangs off VM.
2020-10-13 23:49:19 +02:00
#include <LibJS/Runtime/CommonPropertyNames.h>
LibJS: Add a JS::Completion class and JS::ThrowCompletionOr<T> template We decided that we want to move away from throwing exceptions in AOs and regular functions implicitly and then returning some default-constructed value (usually an empty JS::Value) - this requires remembering to check for an exception at the call site, which is error-prone. It's also awkward for return values that cannot be default-constructed, e.g. MarkedValueList. Instead, the thrown value should be part of the function return value. The solution to this is moving closer to the spec and using something they call "completion records": https://tc39.es/ecma262/#sec-completion-record-specification-type This has various advantages: - It becomes crystal clear whether some AO can fail or not, and errors need to be handled and values unwrapped explicitly (for that reason compatibility with the TRY() macro is already built-in, and a similar TRY_OR_DISCARD() macro has been added specifically for use in LibJS, while the majority of functions doesn't return ThrowCompletionOr yet) - We no longer need to mix "valid" and "invalid" values of various types for the success and exception outcomes (e.g. null/non-null AK::String, empty/non-empty JS::Value) - Subsequently it's no longer possible to accidentally use an exception outcome return value as a success outcome return value (e.g. any AO that returns a numeric type would return 0 even after throwing an exception, at least before we started making use of Optional for that) - Eventually the VM will no longer need to store an exception, and temporarily clearing an exception (e.g. to call a function) becomes obsolete - instead, completions will simply propagate up to the caller outside of LibJS, which then can deal with it in any way - Similar to throw we'll be able to implement the functionality of break, continue, and return using completions, which will lead to easier to understand code and fewer workarounds - the current unwinding mechanism is not even remotely similar to the spec's approach The spec's NormalCompletion and ThrowCompletion AOs have been implemented as simple wrappers around the JS::Completion constructor. UpdateEmpty has been implemented as a JS::Completion method. There's also a new VM::throw_completion<T>() helper, which basically works like VM::throw_exception<T>() - it creates a T object (usually a JS::Error), and returns it wrapped in a JS::Completion of Type::Throw. Two temporary usage patterns have emerged: 1. Callee already returns ThrowCompletionOr, but caller doesn't: auto foo = TRY_OR_DISCARD(bar()); 2. Caller already returns ThrowCompletionOr, but callee doesn't: auto foo = bar(); if (auto* exception = vm.exception()) return throw_completion(exception->value()); Eventually all error handling and unwrapping can be done with just TRY() or possibly even operator? in the future :^) Co-authored-by: Andreas Kling <kling@serenityos.org>
2021-09-15 20:46:51 +01:00
#include <LibJS/Runtime/Completion.h>
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
#include <LibJS/Runtime/Error.h>
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
#include <LibJS/Runtime/ErrorTypes.h>
#include <LibJS/Runtime/Exception.h>
LibJS: Reorganize ExecutionContext a little bit - Move it to a separate header file - Annotate the members that represent spec slots - Reorganize the members (by spec vs non-spec)
2021-09-14 18:21:07 +02:00
#include <LibJS/Runtime/ExecutionContext.h>
LibJS: Make native function/property callbacks take VM, not Interpreter More work on decoupling the general runtime from Interpreter. The goal is becoming clearer. Interpreter should be one possible way to execute code inside a VM. In the future we might have other ways :^)
2020-09-27 18:36:49 +02:00
#include <LibJS/Runtime/MarkedValueList.h>
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
#include <LibJS/Runtime/Promise.h>
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
#include <LibJS/Runtime/Value.h>
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
namespace JS {
LibJS: Implement destructuring assignments and function parameters
2021-05-29 16:03:19 +04:30
class Identifier;
struct BindingPattern;
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
enum class ScopeType {
None,
Function,
Block,
Try,
Breakable,
Continuable,
};
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
class VM : public RefCounted<VM> {
public:
LibJS: Add a way to attach custom data to a JS::VM instance This will be used by LibWeb to attach web engine specific stuff that LibJS doesn't need to know about.
2021-09-08 22:58:36 +02:00
struct CustomData {
virtual ~CustomData();
};
static NonnullRefPtr<VM> create(OwnPtr<CustomData> = {});
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
~VM();
Heap& heap() { return m_heap; }
const Heap& heap() const { return m_heap; }
Interpreter& interpreter();
Interpreter* interpreter_if_exists();
void push_interpreter(Interpreter&);
void pop_interpreter(Interpreter&);
LibJS: Add set_exception() and change throw_exception() to take a reference Sometimes we just want to set m_exception to some value we stored previously, without really "throwing" it again - that's what set_exception() does now. Since we have clear_exception(), it does take a reference, i.e. you don't set_exception(nullptr). For consistency I updated throw_exception() to do the same.
2021-04-13 01:02:38 +02:00
Exception* exception() { return m_exception; }
void set_exception(Exception& exception) { m_exception = &exception; }
LibJS: Move the current exception from Interpreter to VM This will allow us to throw exceptions even when there is no active interpreter in the VM.
2020-09-21 15:28:09 +02:00
void clear_exception() { m_exception = nullptr; }
LibJS: Add VM::dump_backtrace() This is just a simple helper that dumps the current VM call stack to the debug console. I find myself rewriting this function over and over, so let's just have it in the tree.
2021-06-06 22:53:44 +02:00
void dump_backtrace() const;
LibJS: Rename InterpreterScope => InterpreterExecutionScope To make it a little clearer what this is for. (This is an RAII helper class for adding and removing an Interpreter to a VM's list of the currently active (executing code) Interpreters.)
2020-09-21 13:36:32 +02:00
class InterpreterExecutionScope {
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
public:
LibJS: Rename InterpreterScope => InterpreterExecutionScope To make it a little clearer what this is for. (This is an RAII helper class for adding and removing an Interpreter to a VM's list of the currently active (executing code) Interpreters.)
2020-09-21 13:36:32 +02:00
InterpreterExecutionScope(Interpreter&);
~InterpreterExecutionScope();
LibJS: Move the current exception from Interpreter to VM This will allow us to throw exceptions even when there is no active interpreter in the VM.
2020-09-21 15:28:09 +02:00
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
private:
Interpreter& m_interpreter;
};
LibJS: GC should gather roots from all active interpreters If we are in a nested execution context, we shouldn't only mark things used by the active interpreter.
2020-09-21 13:47:33 +02:00
void gather_roots(HashTable<Cell*>&);
LibJS: Move well-known symbols to the VM No need to instantiate unique symbols for each Interpreter; they can be VM-global. This reduces the memory cost and startup time anyway.
2020-09-22 16:18:51 +02:00
#define __JS_ENUMERATE(SymbolName, snake_name) \
Symbol* well_known_symbol_##snake_name() const { return m_well_known_symbol_##snake_name; }
JS_ENUMERATE_WELL_KNOWN_SYMBOLS
#undef __JS_ENUMERATE
Symbol* get_global_symbol(const String& description);
LibJS: Keep track of PrimitiveStrings and share them VM now has a string cache which tracks all live PrimitiveStrings and reuses an existing one if possible. This drastically reduces the number of GC-allocated strings in many real-word situations.
2021-10-02 01:36:57 +02:00
HashMap<String, PrimitiveString*>& string_cache() { return m_string_cache; }
LibJS: Let the VM cache an empty ("") PrimitiveString Empty string is extremely common and we can avoid a lot of heap churn by simply caching one in the VM. Primitive strings are immutable anyway so there is no observable behavior change outside of fewer collections.
2020-09-22 16:36:33 +02:00
PrimitiveString& empty_string() { return *m_empty_string; }
LibJS: Give VM a cache of single-ASCII-character PrimitiveString A large number of JS strings are a single ASCII character. This patch adds a 128-entry cache for those strings to the VM. The cost of the cache is 1536 byte of GC heap (all in same block) + 2304 bytes malloc. This avoids a lot of GC heap allocations, and packing all of these in the same heap block is nice for fragmentation as well.
2020-10-22 17:43:48 +02:00
PrimitiveString& single_ascii_character_string(u8 character)
{
Everywhere: Rename ASSERT => VERIFY (...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED) Since all of these checks are done in release builds as well, let's rename them to VERIFY to prevent confusion, as everyone is used to assertions being compiled out in release. We can introduce a new ASSERT macro that is specifically for debug checks, but I'm doing this wholesale conversion first since we've accumulated thousands of these already, and it's not immediately obvious which ones are suitable for ASSERT.
2021-02-23 20:42:32 +01:00
VERIFY(character < 0x80);
LibJS: Give VM a cache of single-ASCII-character PrimitiveString A large number of JS strings are a single ASCII character. This patch adds a 128-entry cache for those strings to the VM. The cost of the cache is 1536 byte of GC heap (all in same block) + 2304 bytes malloc. This avoids a lot of GC heap allocations, and packing all of these in the same heap block is nice for fragmentation as well.
2020-10-22 17:43:48 +02:00
return *m_single_ascii_character_strings[character];
}
LibJS: Let the VM cache an empty ("") PrimitiveString Empty string is extremely common and we can avoid a lot of heap churn by simply caching one in the VM. Primitive strings are immutable anyway so there is no observable behavior change outside of fewer collections.
2020-09-22 16:36:33 +02:00
LibJS: Prevent stack overflow in flatten_into_array() The check for stack space in VM from push_execution_context has been moved to a method on VM called did_reach_stack_space_limit. This allows us to check the stack size in other places besides push_execution_context. We can now verify that we have enough space on the stack before calling flatten_into_array to ensure that we don't cause a stack overflow error when calling the function with a large depth.
2021-08-13 12:59:57 -04:00
bool did_reach_stack_space_limit() const
{
LibJS: Use different stack space limit values for with and without ASAN Instead of having a single limit here, which we had to increase once to work with ASAN enabled, check whether HAS_ADDRESS_SANITIZER is defined and use 32 KiB, and 16 KiB otherwise (which is what we used previously). This idea is shamelessly stolen from V8: https://github.com/v8/v8/blob/b2b44af/src/execution/isolate.cc#L1381-L1387
2021-09-05 20:34:06 +01:00
#ifdef HAS_ADDRESS_SANITIZER
LibJS: Prevent stack overflow in flatten_into_array() The check for stack space in VM from push_execution_context has been moved to a method on VM called did_reach_stack_space_limit. This allows us to check the stack size in other places besides push_execution_context. We can now verify that we have enough space on the stack before calling flatten_into_array to ensure that we don't cause a stack overflow error when calling the function with a large depth.
2021-08-13 12:59:57 -04:00
return m_stack_info.size_free() < 32 * KiB;
LibJS: Use different stack space limit values for with and without ASAN Instead of having a single limit here, which we had to increase once to work with ASAN enabled, check whether HAS_ADDRESS_SANITIZER is defined and use 32 KiB, and 16 KiB otherwise (which is what we used previously). This idea is shamelessly stolen from V8: https://github.com/v8/v8/blob/b2b44af/src/execution/isolate.cc#L1381-L1387
2021-09-05 20:34:06 +01:00
#else
return m_stack_info.size_free() < 16 * KiB;
#endif
LibJS: Prevent stack overflow in flatten_into_array() The check for stack space in VM from push_execution_context has been moved to a method on VM called did_reach_stack_space_limit. This allows us to check the stack size in other places besides push_execution_context. We can now verify that we have enough space on the stack before calling flatten_into_array to ensure that we don't cause a stack overflow error when calling the function with a large depth.
2021-08-13 12:59:57 -04:00
}
LibJS: Rename CallFrame => ExecutionContext This struct represents what the ECMAScript specification calls an "execution context" so let's use the same terminology. :^)
2021-06-24 19:17:45 +02:00
void push_execution_context(ExecutionContext& context, GlobalObject& global_object)
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
{
Everywhere: Rename ASSERT => VERIFY (...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED) Since all of these checks are done in release builds as well, let's rename them to VERIFY to prevent confusion, as everyone is used to assertions being compiled out in release. We can introduce a new ASSERT macro that is specifically for debug checks, but I'm doing this wholesale conversion first since we've accumulated thousands of these already, and it's not immediately obvious which ones are suitable for ASSERT.
2021-02-23 20:42:32 +01:00
VERIFY(!exception());
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
// Ensure we got some stack space left, so the next function call doesn't kill us.
LibJS: Prevent stack overflow in flatten_into_array() The check for stack space in VM from push_execution_context has been moved to a method on VM called did_reach_stack_space_limit. This allows us to check the stack size in other places besides push_execution_context. We can now verify that we have enough space on the stack before calling flatten_into_array to ensure that we don't cause a stack overflow error when calling the function with a large depth.
2021-08-13 12:59:57 -04:00
if (did_reach_stack_space_limit())
LibJS: Add ErrorType::CallStackSizeExceeded I'm about to add another use of this, so let's add an ErrorType for it instead of hardcoding the message for a third time.
2021-09-05 20:13:06 +01:00
throw_exception<Error>(global_object, ErrorType::CallStackSizeExceeded);
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
else
LibJS: Rename CallFrame => ExecutionContext This struct represents what the ECMAScript specification calls an "execution context" so let's use the same terminology. :^)
2021-06-24 19:17:45 +02:00
m_execution_context_stack.append(&context);
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
}
LibJS: Use regular stack for VM call frames instead of Vector storage Keeping the VM call frames in a Vector could cause them to move around underneath us due to Vector resizing. Avoid this issue by allocating CallFrame objects on the stack and having the VM simply keep a list of pointers to each CallFrame, instead of the CallFrames themselves. Fixes #3830. Fixes #3951.
2020-11-07 11:07:17 +01:00
LibJS: Rename CallFrame => ExecutionContext This struct represents what the ECMAScript specification calls an "execution context" so let's use the same terminology. :^)
2021-06-24 19:17:45 +02:00
void pop_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
{
LibJS: Rename CallFrame => ExecutionContext This struct represents what the ECMAScript specification calls an "execution context" so let's use the same terminology. :^)
2021-06-24 19:17:45 +02:00
m_execution_context_stack.take_last();
if (m_execution_context_stack.is_empty() && on_call_stack_emptied)
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
on_call_stack_emptied();
}
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
LibJS: Rename CallFrame => ExecutionContext This struct represents what the ECMAScript specification calls an "execution context" so let's use the same terminology. :^)
2021-06-24 19:17:45 +02:00
ExecutionContext& running_execution_context() { return *m_execution_context_stack.last(); }
ExecutionContext const& running_execution_context() const { return *m_execution_context_stack.last(); }
Vector<ExecutionContext*> const& execution_context_stack() const { return m_execution_context_stack; }
Vector<ExecutionContext*>& execution_context_stack() { return m_execution_context_stack; }
LibJS: Use regular stack for VM call frames instead of Vector storage Keeping the VM call frames in a Vector could cause them to move around underneath us due to Vector resizing. Avoid this issue by allocating CallFrame objects on the stack and having the VM simply keep a list of pointers to each CallFrame, instead of the CallFrames themselves. Fixes #3830. Fixes #3951.
2020-11-07 11:07:17 +01:00
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
Environment const* lexical_environment() const { return running_execution_context().lexical_environment; }
Environment* lexical_environment() { return running_execution_context().lexical_environment; }
LibJS: Split the per-call-frame environment into lexical and variable To better follow the spec, we need to distinguish between the current execution context's lexical environment and variable environment. This patch moves us to having two record pointers, although both of them point at the same environment records for now.
2021-06-22 15:42:44 +02:00
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
Environment const* variable_environment() const { return running_execution_context().variable_environment; }
Environment* variable_environment() { return running_execution_context().variable_environment; }
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
LibJS: Prepare ExecutionContext to store the current Realm Record Also add VM::current_realm() to retrieve it, similar to all the other getters (running_execution_context() et al.).
2021-09-11 20:55:11 +01:00
// https://tc39.es/ecma262/#current-realm
// The value of the Realm component of the running execution context is also called the current Realm Record.
Realm const* current_realm() const { return running_execution_context().realm; }
Realm* current_realm() { return running_execution_context().realm; }
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
bool in_strict_mode() const;
size_t argument_count() const
{
LibJS: Rename CallFrame => ExecutionContext This struct represents what the ECMAScript specification calls an "execution context" so let's use the same terminology. :^)
2021-06-24 19:17:45 +02:00
if (m_execution_context_stack.is_empty())
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 0;
LibJS: Rename CallFrame => ExecutionContext This struct represents what the ECMAScript specification calls an "execution context" so let's use the same terminology. :^)
2021-06-24 19:17:45 +02:00
return running_execution_context().arguments.size();
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
}
Value argument(size_t index) const
{
LibJS: Rename CallFrame => ExecutionContext This struct represents what the ECMAScript specification calls an "execution context" so let's use the same terminology. :^)
2021-06-24 19:17:45 +02:00
if (m_execution_context_stack.is_empty())
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 {};
LibJS: Rename CallFrame => ExecutionContext This struct represents what the ECMAScript specification calls an "execution context" so let's use the same terminology. :^)
2021-06-24 19:17:45 +02:00
auto& arguments = running_execution_context().arguments;
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 index < arguments.size() ? arguments[index] : js_undefined();
}
Value this_value(Object& global_object) const
{
LibJS: Rename CallFrame => ExecutionContext This struct represents what the ECMAScript specification calls an "execution context" so let's use the same terminology. :^)
2021-06-24 19:17:45 +02:00
if (m_execution_context_stack.is_empty())
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 &global_object;
LibJS: Rename CallFrame => ExecutionContext This struct represents what the ECMAScript specification calls an "execution context" so let's use the same terminology. :^)
2021-06-24 19:17:45 +02:00
return running_execution_context().this_value;
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
}
LibJS: Evaluate `this` in terms of ResolveThisBinding
2021-06-25 11:40:03 +02:00
Value resolve_this_binding(GlobalObject&);
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
Value last_value() const { return m_last_value; }
LibJS: Let the bytecode interpreter set the VM's last value
2021-06-10 21:01:44 +02:00
void set_last_value(Badge<Bytecode::Interpreter>, Value value) { m_last_value = value; }
LibJS: Move scope stack from VM back to Interpreter Okay, my vision here is improving. Interpreter should be a thing that executes an AST. The scope stack is irrelevant to the VM proper, so we can move that to the Interpreter. Same with execute_statement().
2020-09-27 16:56:58 +02:00
void set_last_value(Badge<Interpreter>, Value value) { m_last_value = value; }
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
LibJS+AK: Move cross-platform stack bounds code from JS::Heap to AK::StackInfo This will be useful for other things than the Heap, maybe even outside of LibJS.
2020-11-08 12:48:16 +00:00
const StackInfo& stack_info() const { return m_stack_info; };
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
bool underscore_is_last_value() const { return m_underscore_is_last_value; }
void set_underscore_is_last_value(bool b) { m_underscore_is_last_value = b; }
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
u32 execution_generation() const { return m_execution_generation; }
void finish_execution_generation() { ++m_execution_generation; }
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
void unwind(ScopeType type, FlyString label = {})
{
m_unwind_until = type;
LibJS: Pass unwinding target labels a bit more efficiently Use const reference or move semantics when passing these labels.
2021-06-06 11:40:41 +02:00
m_unwind_until_label = move(label);
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
}
LibJS: Unset m_unwind_until_label in stop_unwind() I don't see a reason to keep this intact, that might only surprise us down the line...
2021-04-13 01:04:32 +02:00
void stop_unwind()
{
m_unwind_until = ScopeType::None;
m_unwind_until_label = {};
}
LibJS: Allow multiple labels on the same statement Since there are only a number of statements where labels can actually be used we now also only store labels when necessary. Also now tracks the first continue usage of a label since this might not be valid but that can only be determined after we have parsed the statement. Also ensures the correct error does not get wiped by load_state.
2021-09-18 23:01:54 +02:00
bool should_unwind_until(ScopeType type, Vector<FlyString> const& labels) const
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
{
if (m_unwind_until_label.is_null())
return m_unwind_until == type;
LibJS: Allow multiple labels on the same statement Since there are only a number of statements where labels can actually be used we now also only store labels when necessary. Also now tracks the first continue usage of a label since this might not be valid but that can only be determined after we have parsed the statement. Also ensures the correct error does not get wiped by load_state.
2021-09-18 23:01:54 +02:00
return m_unwind_until == type && any_of(labels.begin(), labels.end(), [&](FlyString const& label) {
return m_unwind_until_label == label;
});
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
}
bool should_unwind() const { return m_unwind_until != ScopeType::None; }
LibJS: Move scope stack from VM back to Interpreter Okay, my vision here is improving. Interpreter should be a thing that executes an AST. The scope stack is irrelevant to the VM proper, so we can move that to the Interpreter. Same with execute_statement().
2020-09-27 16:56:58 +02:00
ScopeType unwind_until() const { return m_unwind_until; }
LibJS: Implement the IteratorClose abstract op and use it where needed
2021-06-14 13:46:02 +03:00
FlyString unwind_until_label() const { return m_unwind_until_label; }
LibJS: Move scope stack from VM back to Interpreter Okay, my vision here is improving. Interpreter should be a thing that executes an AST. The scope stack is irrelevant to the VM proper, so we can move that to the Interpreter. Same with execute_statement().
2020-09-27 16:56:58 +02:00
LibJS: Improve ResolveBinding + add GetIdentifierReference ResolveBinding now matches the spec, while the non-conforming parts are moved to GetIdentifierReference. Implementing this properly requires variable bindings.
2021-07-02 21:54:56 +02:00
Reference resolve_binding(FlyString const&, Environment* = nullptr);
LibJS: Fast non-local variable access :^) This patch introduces the "environment coordinate" concept, which encodes the distance from a variable access to the binding it ends up resolving to. EnvironmentCoordinate has two fields: - hops: The number of hops up the lexical environment chain we have to make before getting to the resolved binding. - index: The index of the resolved binding within its declarative environment record. Whenever a variable lookup resolves somewhere inside a declarative environment, we now cache the coordinates and reuse them in subsequent lookups. This is achieved via a coordinate cache in JS::Identifier. Note that non-strict direct eval() breaks this optimization and so it will not be performed if the resolved environment has been permanently screwed by eval(). This makes variable access *significantly* faster. :^)
2021-10-07 01:06:21 +02:00
Reference get_identifier_reference(Environment*, FlyString, bool strict, size_t hops = 0);
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
template<typename T, typename... Args>
void throw_exception(GlobalObject& global_object, Args&&... args)
{
return throw_exception(global_object, T::create(global_object, forward<Args>(args)...));
}
LibJS: Add set_exception() and change throw_exception() to take a reference Sometimes we just want to set m_exception to some value we stored previously, without really "throwing" it again - that's what set_exception() does now. Since we have clear_exception(), it does take a reference, i.e. you don't set_exception(nullptr). For consistency I updated throw_exception() to do the same.
2021-04-13 01:02:38 +02:00
void throw_exception(Exception&);
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
void throw_exception(GlobalObject& global_object, Value value)
{
LibJS: Add set_exception() and change throw_exception() to take a reference Sometimes we just want to set m_exception to some value we stored previously, without really "throwing" it again - that's what set_exception() does now. Since we have clear_exception(), it does take a reference, i.e. you don't set_exception(nullptr). For consistency I updated throw_exception() to do the same.
2021-04-13 01:02:38 +02:00
return throw_exception(*heap().allocate<Exception>(global_object, value));
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
}
template<typename T, typename... Args>
void throw_exception(GlobalObject& global_object, ErrorType type, Args&&... args)
{
LibJS: Use String::formatted() for throw_exception() message
2020-10-04 13:55:20 +01:00
return throw_exception(global_object, T::create(global_object, String::formatted(type.message(), forward<Args>(args)...)));
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
}
LibJS: Add a JS::Completion class and JS::ThrowCompletionOr<T> template We decided that we want to move away from throwing exceptions in AOs and regular functions implicitly and then returning some default-constructed value (usually an empty JS::Value) - this requires remembering to check for an exception at the call site, which is error-prone. It's also awkward for return values that cannot be default-constructed, e.g. MarkedValueList. Instead, the thrown value should be part of the function return value. The solution to this is moving closer to the spec and using something they call "completion records": https://tc39.es/ecma262/#sec-completion-record-specification-type This has various advantages: - It becomes crystal clear whether some AO can fail or not, and errors need to be handled and values unwrapped explicitly (for that reason compatibility with the TRY() macro is already built-in, and a similar TRY_OR_DISCARD() macro has been added specifically for use in LibJS, while the majority of functions doesn't return ThrowCompletionOr yet) - We no longer need to mix "valid" and "invalid" values of various types for the success and exception outcomes (e.g. null/non-null AK::String, empty/non-empty JS::Value) - Subsequently it's no longer possible to accidentally use an exception outcome return value as a success outcome return value (e.g. any AO that returns a numeric type would return 0 even after throwing an exception, at least before we started making use of Optional for that) - Eventually the VM will no longer need to store an exception, and temporarily clearing an exception (e.g. to call a function) becomes obsolete - instead, completions will simply propagate up to the caller outside of LibJS, which then can deal with it in any way - Similar to throw we'll be able to implement the functionality of break, continue, and return using completions, which will lead to easier to understand code and fewer workarounds - the current unwinding mechanism is not even remotely similar to the spec's approach The spec's NormalCompletion and ThrowCompletion AOs have been implemented as simple wrappers around the JS::Completion constructor. UpdateEmpty has been implemented as a JS::Completion method. There's also a new VM::throw_completion<T>() helper, which basically works like VM::throw_exception<T>() - it creates a T object (usually a JS::Error), and returns it wrapped in a JS::Completion of Type::Throw. Two temporary usage patterns have emerged: 1. Callee already returns ThrowCompletionOr, but caller doesn't: auto foo = TRY_OR_DISCARD(bar()); 2. Caller already returns ThrowCompletionOr, but callee doesn't: auto foo = bar(); if (auto* exception = vm.exception()) return throw_completion(exception->value()); Eventually all error handling and unwrapping can be done with just TRY() or possibly even operator? in the future :^) Co-authored-by: Andreas Kling <kling@serenityos.org>
2021-09-15 20:46:51 +01:00
// 5.2.3.2 Throw an Exception, https://tc39.es/ecma262/#sec-throw-an-exception
template<typename T, typename... Args>
LibJS: Add VM::throw_completion helper for throwing custom Strings
2021-09-21 22:08:38 +03:00
Completion throw_completion(GlobalObject& global_object, Args&&... args)
LibJS: Add a JS::Completion class and JS::ThrowCompletionOr<T> template We decided that we want to move away from throwing exceptions in AOs and regular functions implicitly and then returning some default-constructed value (usually an empty JS::Value) - this requires remembering to check for an exception at the call site, which is error-prone. It's also awkward for return values that cannot be default-constructed, e.g. MarkedValueList. Instead, the thrown value should be part of the function return value. The solution to this is moving closer to the spec and using something they call "completion records": https://tc39.es/ecma262/#sec-completion-record-specification-type This has various advantages: - It becomes crystal clear whether some AO can fail or not, and errors need to be handled and values unwrapped explicitly (for that reason compatibility with the TRY() macro is already built-in, and a similar TRY_OR_DISCARD() macro has been added specifically for use in LibJS, while the majority of functions doesn't return ThrowCompletionOr yet) - We no longer need to mix "valid" and "invalid" values of various types for the success and exception outcomes (e.g. null/non-null AK::String, empty/non-empty JS::Value) - Subsequently it's no longer possible to accidentally use an exception outcome return value as a success outcome return value (e.g. any AO that returns a numeric type would return 0 even after throwing an exception, at least before we started making use of Optional for that) - Eventually the VM will no longer need to store an exception, and temporarily clearing an exception (e.g. to call a function) becomes obsolete - instead, completions will simply propagate up to the caller outside of LibJS, which then can deal with it in any way - Similar to throw we'll be able to implement the functionality of break, continue, and return using completions, which will lead to easier to understand code and fewer workarounds - the current unwinding mechanism is not even remotely similar to the spec's approach The spec's NormalCompletion and ThrowCompletion AOs have been implemented as simple wrappers around the JS::Completion constructor. UpdateEmpty has been implemented as a JS::Completion method. There's also a new VM::throw_completion<T>() helper, which basically works like VM::throw_exception<T>() - it creates a T object (usually a JS::Error), and returns it wrapped in a JS::Completion of Type::Throw. Two temporary usage patterns have emerged: 1. Callee already returns ThrowCompletionOr, but caller doesn't: auto foo = TRY_OR_DISCARD(bar()); 2. Caller already returns ThrowCompletionOr, but callee doesn't: auto foo = bar(); if (auto* exception = vm.exception()) return throw_completion(exception->value()); Eventually all error handling and unwrapping can be done with just TRY() or possibly even operator? in the future :^) Co-authored-by: Andreas Kling <kling@serenityos.org>
2021-09-15 20:46:51 +01:00
{
LibJS: Add VM::throw_completion helper for throwing custom Strings
2021-09-21 22:08:38 +03:00
auto* error = T::create(global_object, forward<Args>(args)...);
LibJS: Add a JS::Completion class and JS::ThrowCompletionOr<T> template We decided that we want to move away from throwing exceptions in AOs and regular functions implicitly and then returning some default-constructed value (usually an empty JS::Value) - this requires remembering to check for an exception at the call site, which is error-prone. It's also awkward for return values that cannot be default-constructed, e.g. MarkedValueList. Instead, the thrown value should be part of the function return value. The solution to this is moving closer to the spec and using something they call "completion records": https://tc39.es/ecma262/#sec-completion-record-specification-type This has various advantages: - It becomes crystal clear whether some AO can fail or not, and errors need to be handled and values unwrapped explicitly (for that reason compatibility with the TRY() macro is already built-in, and a similar TRY_OR_DISCARD() macro has been added specifically for use in LibJS, while the majority of functions doesn't return ThrowCompletionOr yet) - We no longer need to mix "valid" and "invalid" values of various types for the success and exception outcomes (e.g. null/non-null AK::String, empty/non-empty JS::Value) - Subsequently it's no longer possible to accidentally use an exception outcome return value as a success outcome return value (e.g. any AO that returns a numeric type would return 0 even after throwing an exception, at least before we started making use of Optional for that) - Eventually the VM will no longer need to store an exception, and temporarily clearing an exception (e.g. to call a function) becomes obsolete - instead, completions will simply propagate up to the caller outside of LibJS, which then can deal with it in any way - Similar to throw we'll be able to implement the functionality of break, continue, and return using completions, which will lead to easier to understand code and fewer workarounds - the current unwinding mechanism is not even remotely similar to the spec's approach The spec's NormalCompletion and ThrowCompletion AOs have been implemented as simple wrappers around the JS::Completion constructor. UpdateEmpty has been implemented as a JS::Completion method. There's also a new VM::throw_completion<T>() helper, which basically works like VM::throw_exception<T>() - it creates a T object (usually a JS::Error), and returns it wrapped in a JS::Completion of Type::Throw. Two temporary usage patterns have emerged: 1. Callee already returns ThrowCompletionOr, but caller doesn't: auto foo = TRY_OR_DISCARD(bar()); 2. Caller already returns ThrowCompletionOr, but callee doesn't: auto foo = bar(); if (auto* exception = vm.exception()) return throw_completion(exception->value()); Eventually all error handling and unwrapping can be done with just TRY() or possibly even operator? in the future :^) Co-authored-by: Andreas Kling <kling@serenityos.org>
2021-09-15 20:46:51 +01:00
// NOTE: This is temporary until we remove VM::exception().
throw_exception(global_object, error);
return JS::throw_completion(error);
}
LibJS: Add VM::throw_completion helper for throwing custom Strings
2021-09-21 22:08:38 +03:00
template<typename T, typename... Args>
Completion throw_completion(GlobalObject& global_object, ErrorType type, Args&&... args)
{
return throw_completion<T>(global_object, String::formatted(type.message(), forward<Args>(args)...));
}
LibJS: Rename Function => FunctionObject
2021-06-27 21:48:34 +02:00
Value construct(FunctionObject&, FunctionObject& new_target, Optional<MarkedValueList> arguments);
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
LibJS: Implement console.assert()
2021-04-18 17:08:14 +02:00
String join_arguments(size_t start_index = 0) const;
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
LibJS: Bring function environment records closer to the spec This patch adds FunctionEnvironmentRecord as a subclass of the existing DeclarativeEnvironmentRecord. Things that are specific to function environment records move into there, simplifying the base. Most of the abstract operations related to function environment records are rewritten to match the spec exactly. I also had to implement GetThisEnvironment() and GetSuperConstructor() to keep tests working after the changes, so that's nice as well. :^)
2021-06-22 13:30:48 +02:00
Value get_new_target();
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
LibJS: Make native function/property callbacks take VM, not Interpreter More work on decoupling the general runtime from Interpreter. The goal is becoming clearer. Interpreter should be one possible way to execute code inside a VM. In the future we might have other ways :^)
2020-09-27 18:36:49 +02:00
template<typename... Args>
LibJS: Convert Value::invoke and VM::call to ThrowCompletionOr
2021-09-23 20:56:28 +03:00
[[nodiscard]] ALWAYS_INLINE ThrowCompletionOr<Value> call(FunctionObject& function, Value this_value, Args... args)
LibJS: Make native function/property callbacks take VM, not Interpreter More work on decoupling the general runtime from Interpreter. The goal is becoming clearer. Interpreter should be one possible way to execute code inside a VM. In the future we might have other ways :^)
2020-09-27 18:36:49 +02:00
{
Everywhere: Switch from (void) to [[maybe_unused]] (#4473) Problem: - `(void)` simply casts the expression to void. This is understood to indicate that it is ignored, but this is really a compiler trick to get the compiler to not generate a warning. Solution: - Use the `[[maybe_unused]]` attribute to indicate the value is unused. Note: - Functions taking a `(void)` argument list have also been changed to `()` because this is not needed and shows up in the same grep command.
2020-12-20 16:09:48 -07:00
if constexpr (sizeof...(Args) > 0) {
LibJS: Implement [[Call]] and [[Construct]] internal slots properly This patch implements: - Spec compliant [[Call]] and [[Construct]] internal slots, as virtual FunctionObject::internal_{call,construct}(). These effectively replace the old virtual FunctionObject::{call,construct}(), but with several advantages: - Clear and consistent naming, following the object internal methods - Use of completions - internal_construct() returns an Object, and not Value! This has been a source of confusion for a long time, since in the spec there's always an Object returned but the Value return type in LibJS meant that this could not be fully trusted and something could screw you over. - Arguments are passed explicitly in form of a MarkedValueList, allowing manipulation (BoundFunction). We still put them on the execution context as a lot of code depends on it (VM::arguments()), but not from the Call() / Construct() AOs anymore, which now allows for bypassing them and invoking [[Call]] / [[Construct]] directly. Nothing but Call() / Construct() themselves do that at the moment, but future additions to ECMA262 or already existing web specs might. - Spec compliant, standalone Call() and Construct() AOs: currently the closest we have is VM::{call,construct}(), but those try to cater to all the different function object subclasses at once, resulting in a horrible mess and calling AOs with functions they should never be called with; most prominently PrepareForOrdinaryCall and OrdinaryCallBindThis, which are only for ECMAScriptFunctionObject. As a result this also contains an implicit optimization: we no longer need to create a new function environment for NativeFunctions - which, worth mentioning, is what started this whole crusade in the first place :^)
2021-10-08 20:37:21 +01:00
MarkedValueList arguments_list { heap() };
(..., arguments_list.append(move(args)));
return call(function, this_value, move(arguments_list));
LibJS: Make native function/property callbacks take VM, not Interpreter More work on decoupling the general runtime from Interpreter. The goal is becoming clearer. Interpreter should be one possible way to execute code inside a VM. In the future we might have other ways :^)
2020-09-27 18:36:49 +02:00
}
return call(function, this_value);
}
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: Cache commonly used FlyStrings in the VM Roughly 7% of test-js runtime was spent creating FlyStrings from string literals. This patch frontloads that work and caches all the commonly used names in LibJS on a CommonPropertyNames struct that hangs off VM.
2020-10-13 23:49:19 +02:00
CommonPropertyNames names;
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
void run_queued_promise_jobs();
void enqueue_promise_job(NativeFunction&);
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
void run_queued_finalization_registry_cleanup_jobs();
void enqueue_finalization_registry_cleanup_job(FinalizationRegistry&);
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
void promise_rejection_tracker(const Promise&, Promise::RejectionOperation) const;
LibJS: Stop qualifying AK::Function Now that JS function objects are JS::FunctionObject, we can stop qualifying AK::Function and just say "Function" everywhere. Nice. :^)
2021-06-27 22:38:42 +02:00
Function<void()> on_call_stack_emptied;
Function<void(const Promise&)> on_promise_unhandled_rejection;
Function<void(const Promise&)> on_promise_rejection_handled;
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
LibJS: Implement [[Call]] and [[Construct]] internal slots properly This patch implements: - Spec compliant [[Call]] and [[Construct]] internal slots, as virtual FunctionObject::internal_{call,construct}(). These effectively replace the old virtual FunctionObject::{call,construct}(), but with several advantages: - Clear and consistent naming, following the object internal methods - Use of completions - internal_construct() returns an Object, and not Value! This has been a source of confusion for a long time, since in the spec there's always an Object returned but the Value return type in LibJS meant that this could not be fully trusted and something could screw you over. - Arguments are passed explicitly in form of a MarkedValueList, allowing manipulation (BoundFunction). We still put them on the execution context as a lot of code depends on it (VM::arguments()), but not from the Call() / Construct() AOs anymore, which now allows for bypassing them and invoking [[Call]] / [[Construct]] directly. Nothing but Call() / Construct() themselves do that at the moment, but future additions to ECMA262 or already existing web specs might. - Spec compliant, standalone Call() and Construct() AOs: currently the closest we have is VM::{call,construct}(), but those try to cater to all the different function object subclasses at once, resulting in a horrible mess and calling AOs with functions they should never be called with; most prominently PrepareForOrdinaryCall and OrdinaryCallBindThis, which are only for ECMAScriptFunctionObject. As a result this also contains an implicit optimization: we no longer need to create a new function environment for NativeFunctions - which, worth mentioning, is what started this whole crusade in the first place :^)
2021-10-08 20:37:21 +01:00
ThrowCompletionOr<void> initialize_instance_elements(Object& object, ECMAScriptFunctionObject& constructor);
LibJS: Add support for public fields in classes
2021-08-28 17:11:05 +02:00
LibJS: Add a way to attach custom data to a JS::VM instance This will be used by LibWeb to attach web engine specific stuff that LibJS doesn't need to know about.
2021-09-08 22:58:36 +02:00
CustomData* custom_data() { return m_custom_data; }
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
ThrowCompletionOr<void> destructuring_assignment_evaluation(NonnullRefPtr<BindingPattern> const& target, Value value, GlobalObject& global_object);
ThrowCompletionOr<void> binding_initialization(FlyString const& target, Value value, Environment* environment, GlobalObject& global_object);
ThrowCompletionOr<void> binding_initialization(NonnullRefPtr<BindingPattern> const& target, Value value, Environment* environment, GlobalObject& global_object);
ThrowCompletionOr<Value> named_evaluation_if_anonymous_function(GlobalObject& global_object, ASTNode const& expression, FlyString const& name);
LibJS: Add a way to save/restore the entire execution context stack This will be used by LibWeb to squirrel away the stack while performing a microtask checkpoint in some cases. VM will simply consider saved execution context stacks as GC roots as well.
2021-10-03 14:52:53 +02:00
void save_execution_context_stack();
void restore_execution_context_stack();
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
private:
LibJS: Add a way to attach custom data to a JS::VM instance This will be used by LibWeb to attach web engine specific stuff that LibJS doesn't need to know about.
2021-09-08 22:58:36 +02:00
explicit VM(OwnPtr<CustomData>);
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
LibJS: Convert Value::invoke and VM::call to ThrowCompletionOr
2021-09-23 20:56:28 +03:00
[[nodiscard]] ThrowCompletionOr<Value> call_internal(FunctionObject&, Value this_value, Optional<MarkedValueList> arguments);
LibJS: Make native function/property callbacks take VM, not Interpreter More work on decoupling the general runtime from Interpreter. The goal is becoming clearer. Interpreter should be one possible way to execute code inside a VM. In the future we might have other ways :^)
2020-09-27 18:36:49 +02:00
LibJS: Rename PropertyName to PropertyKey Let's use the same name as the spec. :^)
2021-10-24 16:01:24 +02:00
ThrowCompletionOr<Object*> copy_data_properties(Object& rest_object, Object const& source, HashTable<PropertyKey, PropertyNameTraits> const& seen_names, GlobalObject& global_object);
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
ThrowCompletionOr<void> property_binding_initialization(BindingPattern const& binding, Value value, Environment* environment, GlobalObject& global_object);
ThrowCompletionOr<void> iterator_binding_initialization(BindingPattern const& binding, Object* iterator, bool& iterator_done, Environment* environment, GlobalObject& global_object);
LibJS: Move the current exception from Interpreter to VM This will allow us to throw exceptions even when there is no active interpreter in the VM.
2020-09-21 15:28:09 +02:00
Exception* m_exception { nullptr };
LibJS: Keep track of PrimitiveStrings and share them VM now has a string cache which tracks all live PrimitiveStrings and reuses an existing one if possible. This drastically reduces the number of GC-allocated strings in many real-word situations.
2021-10-02 01:36:57 +02:00
HashMap<String, PrimitiveString*> m_string_cache;
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
Heap m_heap;
Vector<Interpreter*> m_interpreters;
LibJS: Move well-known symbols to the VM No need to instantiate unique symbols for each Interpreter; they can be VM-global. This reduces the memory cost and startup time anyway.
2020-09-22 16:18:51 +02:00
LibJS: Rename CallFrame => ExecutionContext This struct represents what the ECMAScript specification calls an "execution context" so let's use the same terminology. :^)
2021-06-24 19:17:45 +02:00
Vector<ExecutionContext*> m_execution_context_stack;
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
LibJS: Add a way to save/restore the entire execution context stack This will be used by LibWeb to squirrel away the stack while performing a microtask checkpoint in some cases. VM will simply consider saved execution context stacks as GC roots as well.
2021-10-03 14:52:53 +02:00
Vector<Vector<ExecutionContext*>> m_saved_execution_context_stacks;
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
Value m_last_value;
ScopeType m_unwind_until { ScopeType::None };
FlyString m_unwind_until_label;
LibJS+AK: Move cross-platform stack bounds code from JS::Heap to AK::StackInfo This will be useful for other things than the Heap, maybe even outside of LibJS.
2020-11-08 12:48:16 +00:00
StackInfo m_stack_info;
LibJS: Move well-known symbols to the VM No need to instantiate unique symbols for each Interpreter; they can be VM-global. This reduces the memory cost and startup time anyway.
2020-09-22 16:18:51 +02:00
HashMap<String, Symbol*> m_global_symbol_map;
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
Vector<NativeFunction*> m_promise_jobs;
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
Vector<FinalizationRegistry*> m_finalization_registry_cleanup_jobs;
LibJS: Let the VM cache an empty ("") PrimitiveString Empty string is extremely common and we can avoid a lot of heap churn by simply caching one in the VM. Primitive strings are immutable anyway so there is no observable behavior change outside of fewer collections.
2020-09-22 16:36:33 +02:00
PrimitiveString* m_empty_string { nullptr };
LibJS: Give VM a cache of single-ASCII-character PrimitiveString A large number of JS strings are a single ASCII character. This patch adds a 128-entry cache for those strings to the VM. The cost of the cache is 1536 byte of GC heap (all in same block) + 2304 bytes malloc. This avoids a lot of GC heap allocations, and packing all of these in the same heap block is nice for fragmentation as well.
2020-10-22 17:43:48 +02:00
PrimitiveString* m_single_ascii_character_strings[128] {};
LibJS: Let the VM cache an empty ("") PrimitiveString Empty string is extremely common and we can avoid a lot of heap churn by simply caching one in the VM. Primitive strings are immutable anyway so there is no observable behavior change outside of fewer collections.
2020-09-22 16:36:33 +02:00
LibJS: Move well-known symbols to the VM No need to instantiate unique symbols for each Interpreter; they can be VM-global. This reduces the memory cost and startup time anyway.
2020-09-22 16:18:51 +02:00
#define __JS_ENUMERATE(SymbolName, snake_name) \
Symbol* m_well_known_symbol_##snake_name { nullptr };
JS_ENUMERATE_WELL_KNOWN_SYMBOLS
#undef __JS_ENUMERATE
LibJS: Add a scope object abstraction Both GlobalObject and LexicalEnvironment now inherit from ScopeObject, and the VM's call frames point to a ScopeObject chain rather than just a LexicalEnvironment chain. This gives us much more flexibility to implement things like "with", and also unifies some of the code paths that previously required special handling of the global object. There's a bunch of more cleanup that can be done in the wake of this change, and there might be some oversights in the handling of the "super" keyword, but this generally seems like a good architectural improvement. :^)
2020-11-28 16:02:27 +01:00
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
bool m_underscore_is_last_value { false };
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
u32 m_execution_generation { 0 };
LibJS: Add a way to attach custom data to a JS::VM instance This will be used by LibWeb to attach web engine specific stuff that LibJS doesn't need to know about.
2021-09-08 22:58:36 +02:00
OwnPtr<CustomData> m_custom_data;
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
};
LibJS: Make native function/property callbacks take VM, not Interpreter More work on decoupling the general runtime from Interpreter. The goal is becoming clearer. Interpreter should be one possible way to execute code inside a VM. In the future we might have other ways :^)
2020-09-27 18:36:49 +02:00
template<>
LibJS: Convert Value::invoke and VM::call to ThrowCompletionOr
2021-09-23 20:56:28 +03:00
[[nodiscard]] ALWAYS_INLINE ThrowCompletionOr<Value> VM::call(FunctionObject& function, Value this_value, MarkedValueList arguments) { return call_internal(function, this_value, move(arguments)); }
LibJS: Make native function/property callbacks take VM, not Interpreter More work on decoupling the general runtime from Interpreter. The goal is becoming clearer. Interpreter should be one possible way to execute code inside a VM. In the future we might have other ways :^)
2020-09-27 18:36:49 +02:00
template<>
LibJS: Convert Value::invoke and VM::call to ThrowCompletionOr
2021-09-23 20:56:28 +03:00
[[nodiscard]] ALWAYS_INLINE ThrowCompletionOr<Value> VM::call(FunctionObject& function, Value this_value, Optional<MarkedValueList> arguments) { return call_internal(function, this_value, move(arguments)); }
LibJS: Make native function/property callbacks take VM, not Interpreter More work on decoupling the general runtime from Interpreter. The goal is becoming clearer. Interpreter should be one possible way to execute code inside a VM. In the future we might have other ways :^)
2020-09-27 18:36:49 +02:00
template<>
LibJS: Convert Value::invoke and VM::call to ThrowCompletionOr
2021-09-23 20:56:28 +03:00
[[nodiscard]] ALWAYS_INLINE ThrowCompletionOr<Value> VM::call(FunctionObject& function, Value this_value) { return call(function, this_value, Optional<MarkedValueList> {}); }
LibJS: Make native function/property callbacks take VM, not Interpreter More work on decoupling the general runtime from Interpreter. The goal is becoming clearer. Interpreter should be one possible way to execute code inside a VM. In the future we might have other ways :^)
2020-09-27 18:36:49 +02:00
LibJS: Always inline Cell::vm() and Cell::heap()
2021-03-21 17:20:07 +01:00
ALWAYS_INLINE Heap& Cell::heap() const
{
return HeapBlock::from_cell(this)->heap();
}
ALWAYS_INLINE VM& Cell::vm() const
{
return heap().vm();
}
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
}
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