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ladybird/Libraries/LibJS/Bytecode/Interpreter.h

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LibJS: Start fleshing out a bytecode for the JavaScript engine :^) This patch begins the work of implementing JavaScript execution in a bytecode VM instead of an AST tree-walk interpreter. It's probably quite naive, but we have to start somewhere. The basic idea is that you call Bytecode::Generator::generate() on an AST node and it hands you back a Bytecode::Block filled with instructions that can then be interpreted by a Bytecode::Interpreter. This first version only implements two instructions: Load and Add. :^) Each bytecode block has infinity registers, and the interpreter resizes its register file to fit the block being executed. Two new `js` options are added in this patch as well: `-d` will dump the generated bytecode `-b` will execute the generated bytecode Note that unless `-d` and/or `-b` are specified, none of the bytecode related stuff in LibJS runs at all. This is implemented in parallel with the existing AST interpreter. :^)
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/*
Meta: Update my e-mail address everywhere
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* Copyright (c) 2021, Andreas Kling <andreas@ladybird.org>
LibJS: Start fleshing out a bytecode for the JavaScript engine :^) This patch begins the work of implementing JavaScript execution in a bytecode VM instead of an AST tree-walk interpreter. It's probably quite naive, but we have to start somewhere. The basic idea is that you call Bytecode::Generator::generate() on an AST node and it hands you back a Bytecode::Block filled with instructions that can then be interpreted by a Bytecode::Interpreter. This first version only implements two instructions: Load and Add. :^) Each bytecode block has infinity registers, and the interpreter resizes its register file to fit the block being executed. Two new `js` options are added in this patch as well: `-d` will dump the generated bytecode `-b` will execute the generated bytecode Note that unless `-d` and/or `-b` are specified, none of the bytecode related stuff in LibJS runs at all. This is implemented in parallel with the existing AST interpreter. :^)
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*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
LibJS/JIT: Provide source location information for JIT code This works by walking a backtrace until the currently executing native executable is found, and then mapping the native address to its bytecode instruction.
2023-10-30 22:06:27 +01:00
#include <LibJS/Bytecode/Executable.h>
LibJS: Add basic support for while loops in the bytecode engine This introduces two new instructions: Jump and JumpIfFalse. Jumps are made to a Bytecode::Label, which is a simple object that represents a location in the bytecode stream. Note that you may not always know the target of a jump when adding the jump instruction itself, but we can just update the instruction later on during codegen once we know where the jump target is. The Bytecode::Interpreter now implements jumping via a jump slot that gets checked after each instruction to see if a jump is pending. If not, we just increment the PC as usual.
2021-06-04 12:07:38 +02:00
#include <LibJS/Bytecode/Label.h>
LibJS: Start fleshing out a bytecode for the JavaScript engine :^) This patch begins the work of implementing JavaScript execution in a bytecode VM instead of an AST tree-walk interpreter. It's probably quite naive, but we have to start somewhere. The basic idea is that you call Bytecode::Generator::generate() on an AST node and it hands you back a Bytecode::Block filled with instructions that can then be interpreted by a Bytecode::Interpreter. This first version only implements two instructions: Load and Add. :^) Each bytecode block has infinity registers, and the interpreter resizes its register file to fit the block being executed. Two new `js` options are added in this patch as well: `-d` will dump the generated bytecode `-b` will execute the generated bytecode Note that unless `-d` and/or `-b` are specified, none of the bytecode related stuff in LibJS runs at all. This is implemented in parallel with the existing AST interpreter. :^)
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#include <LibJS/Bytecode/Register.h>
#include <LibJS/Forward.h>
#include <LibJS/Heap/Cell.h>
LibJS/Bytecode: Simplify Bytecode::Interpreter lifetime model The JS::VM now owns the one Bytecode::Interpreter. We no longer have multiple bytecode interpreters, and there is no concept of a "current" bytecode interpreter. If you ask for VM::bytecode_interpreter_if_exists(), it will return null if we're not running the program in "bytecode enabled" mode. If you ask for VM::bytecode_interpreter(), it will return a bytecode interpreter in all modes. This is used for situations where even the AST interpreter switches to bytecode mode (generators, etc.)
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#include <LibJS/Runtime/FunctionKind.h>
LibJS: Implement the NewClass opcode
2022-02-11 22:38:21 +03:30
#include <LibJS/Runtime/VM.h>
LibJS: Start fleshing out a bytecode for the JavaScript engine :^) This patch begins the work of implementing JavaScript execution in a bytecode VM instead of an AST tree-walk interpreter. It's probably quite naive, but we have to start somewhere. The basic idea is that you call Bytecode::Generator::generate() on an AST node and it hands you back a Bytecode::Block filled with instructions that can then be interpreted by a Bytecode::Interpreter. This first version only implements two instructions: Load and Add. :^) Each bytecode block has infinity registers, and the interpreter resizes its register file to fit the block being executed. Two new `js` options are added in this patch as well: `-d` will dump the generated bytecode `-b` will execute the generated bytecode Note that unless `-d` and/or `-b` are specified, none of the bytecode related stuff in LibJS runs at all. This is implemented in parallel with the existing AST interpreter. :^)
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#include <LibJS/Runtime/Value.h>
namespace JS::Bytecode {
Ladybird+LibJS: Add CLI option to run browser with LibJS bytecode VM This required quite a bit of plumbing, but now you can run ladybird --use-bytecode
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class InstructionStreamIterator;
LibJS: Start fleshing out a bytecode for the JavaScript engine :^) This patch begins the work of implementing JavaScript execution in a bytecode VM instead of an AST tree-walk interpreter. It's probably quite naive, but we have to start somewhere. The basic idea is that you call Bytecode::Generator::generate() on an AST node and it hands you back a Bytecode::Block filled with instructions that can then be interpreted by a Bytecode::Interpreter. This first version only implements two instructions: Load and Add. :^) Each bytecode block has infinity registers, and the interpreter resizes its register file to fit the block being executed. Two new `js` options are added in this patch as well: `-d` will dump the generated bytecode `-b` will execute the generated bytecode Note that unless `-d` and/or `-b` are specified, none of the bytecode related stuff in LibJS runs at all. This is implemented in parallel with the existing AST interpreter. :^)
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class Interpreter {
public:
LibJS/Bytecode: Simplify Bytecode::Interpreter lifetime model The JS::VM now owns the one Bytecode::Interpreter. We no longer have multiple bytecode interpreters, and there is no concept of a "current" bytecode interpreter. If you ask for VM::bytecode_interpreter_if_exists(), it will return null if we're not running the program in "bytecode enabled" mode. If you ask for VM::bytecode_interpreter(), it will return a bytecode interpreter in all modes. This is used for situations where even the AST interpreter switches to bytecode mode (generators, etc.)
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explicit Interpreter(VM&);
LibJS: Start fleshing out a bytecode for the JavaScript engine :^) This patch begins the work of implementing JavaScript execution in a bytecode VM instead of an AST tree-walk interpreter. It's probably quite naive, but we have to start somewhere. The basic idea is that you call Bytecode::Generator::generate() on an AST node and it hands you back a Bytecode::Block filled with instructions that can then be interpreted by a Bytecode::Interpreter. This first version only implements two instructions: Load and Add. :^) Each bytecode block has infinity registers, and the interpreter resizes its register file to fit the block being executed. Two new `js` options are added in this patch as well: `-d` will dump the generated bytecode `-b` will execute the generated bytecode Note that unless `-d` and/or `-b` are specified, none of the bytecode related stuff in LibJS runs at all. This is implemented in parallel with the existing AST interpreter. :^)
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~Interpreter();
LibJS/Bytecode: Cache realm, global object, and more in interpreter Instead of looking these up in the VM execution context stack whenever we need them, we now just cache them in the interpreter when entering a new call frame.
2024-02-28 18:49:52 +01:00
[[nodiscard]] Realm& realm() { return *m_realm; }
[[nodiscard]] Object& global_object() { return *m_global_object; }
[[nodiscard]] DeclarativeEnvironment& global_declarative_environment() { return *m_global_declarative_environment; }
LibJS: Add a VM accessor to Bytecode::Interpreter :^)
2021-06-03 18:26:13 +02:00
VM& vm() { return m_vm; }
LibJS/Bytecode: Add Bytecode::Operand An Operand is either a register, a local, or a constant (index into the executable's constant table)
2024-02-02 10:19:17 +01:00
VM const& vm() const { return m_vm; }
LibJS: Start fleshing out a bytecode for the JavaScript engine :^) This patch begins the work of implementing JavaScript execution in a bytecode VM instead of an AST tree-walk interpreter. It's probably quite naive, but we have to start somewhere. The basic idea is that you call Bytecode::Generator::generate() on an AST node and it hands you back a Bytecode::Block filled with instructions that can then be interpreted by a Bytecode::Interpreter. This first version only implements two instructions: Load and Add. :^) Each bytecode block has infinity registers, and the interpreter resizes its register file to fit the block being executed. Two new `js` options are added in this patch as well: `-d` will dump the generated bytecode `-b` will execute the generated bytecode Note that unless `-d` and/or `-b` are specified, none of the bytecode related stuff in LibJS runs at all. This is implemented in parallel with the existing AST interpreter. :^)
2021-06-03 10:46:30 +02:00
LibGC+Everywhere: Factor out a LibGC from LibJS Resulting in a massive rename across almost everywhere! Alongside the namespace change, we now have the following names: * JS::NonnullGCPtr -> GC::Ref * JS::GCPtr -> GC::Ptr * JS::HeapFunction -> GC::Function * JS::CellImpl -> GC::Cell * JS::Handle -> GC::Root
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ThrowCompletionOr<Value> run(Script&, GC::Ptr<Environment> lexical_environment_override = nullptr);
LibJS/Bytecode: Leave GlobalDeclarationInstantiation in C++ Don't try to implement this AO in bytecode. Instead, the bytecode Interpreter class now has a run() API with the same inputs as the AST interpreter. It sets up the necessary environments etc, including invoking the GlobalDeclarationInstantiation AO.
2023-06-15 12:36:57 +02:00
ThrowCompletionOr<Value> run(SourceTextModule&);
LibJS: Make Value() default-construct the undefined value The special empty value (that we use for array holes, Optional<Value> when empty and a few other other placeholder/sentinel tasks) still exists, but you now create one via JS::js_special_empty_value() and check for it with Value::is_special_empty_value(). The main idea here is to make it very unlikely to accidentally create an unexpected special empty value.
2025-04-04 23:16:34 +02:00
ThrowCompletionOr<Value> run(Bytecode::Executable& executable, Optional<size_t> entry_point = {}, Value initial_accumulator_value = js_special_empty_value())
LibJS: Make Bytecode::Interpreter return the popped frame And use it to _correctly_ implement state saving for generators. Prior to this, we were capturing the caller frame, which is completely irrelevant to the generator frame.
2021-11-11 00:34:44 +03:30
{
LibJS/Bytecode: Flatten bytecode to a contiguous representation Instead of keeping bytecode as a set of disjoint basic blocks on the malloc heap, bytecode is now a contiguous sequence of bytes(!) The transformation happens at the end of Bytecode::Generator::generate() and the only really hairy part is rerouting jump labels. This required solving a few problems: - The interpreter execution loop had to change quite a bit, since we were storing BasicBlock pointers all over the place, and control transfer was done by redirecting the interpreter's current block. - Exception handlers & finalizers are now stored per-bytecode-range in a side table in Executable. - The interpreter now has a plain program counter instead of a stream iterator. This actually makes error stack generation a bit nicer since we just have to deal with a number instead of reaching into the iterator. This yields a 25% performance improvement on this microbenchmark: for (let i = 0; i < 1_000_000; ++i) { } But basically everything gets faster. :^)
2024-05-06 06:44:08 +02:00
auto result_and_return_register = run_executable(executable, entry_point, initial_accumulator_value);
LibJS: Merge CallFrame into ExecutionContext Before this change both ExecutionContext and CallFrame were created before executing function/module/script with a couple exceptions: - executable created for default function argument evaluation has to run in function's execution context. - `execute_ast_node()` where executable compiled for ASTNode has to be executed in running execution context. This change moves all members previously owned by CallFrame into ExecutionContext, and makes two exceptions where an executable that does not have a corresponding execution context saves and restores registers before running. Now, all execution state lives in a single entity, which makes it a bit easier to reason about and opens opportunities for optimizations, such as moving registers and local variables into a single array.
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return move(result_and_return_register.value);
LibJS: Make Bytecode::Interpreter return the popped frame And use it to _correctly_ implement state saving for generators. Prior to this, we were capturing the caller frame, which is completely irrelevant to the generator frame.
2021-11-11 00:34:44 +03:30
}
LibJS: Merge CallFrame into ExecutionContext Before this change both ExecutionContext and CallFrame were created before executing function/module/script with a couple exceptions: - executable created for default function argument evaluation has to run in function's execution context. - `execute_ast_node()` where executable compiled for ASTNode has to be executed in running execution context. This change moves all members previously owned by CallFrame into ExecutionContext, and makes two exceptions where an executable that does not have a corresponding execution context saves and restores registers before running. Now, all execution state lives in a single entity, which makes it a bit easier to reason about and opens opportunities for optimizations, such as moving registers and local variables into a single array.
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struct ResultAndReturnRegister {
LibJS+LibTest+js: Convert BC::Interpreter::run to ThrowCompletionOr<> Note that this is just a shallow API change.
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ThrowCompletionOr<Value> value;
LibJS: Merge CallFrame into ExecutionContext Before this change both ExecutionContext and CallFrame were created before executing function/module/script with a couple exceptions: - executable created for default function argument evaluation has to run in function's execution context. - `execute_ast_node()` where executable compiled for ASTNode has to be executed in running execution context. This change moves all members previously owned by CallFrame into ExecutionContext, and makes two exceptions where an executable that does not have a corresponding execution context saves and restores registers before running. Now, all execution state lives in a single entity, which makes it a bit easier to reason about and opens opportunities for optimizations, such as moving registers and local variables into a single array.
2024-05-01 19:33:49 +02:00
Value return_register_value;
LibJS: Make Bytecode::Interpreter return the popped frame And use it to _correctly_ implement state saving for generators. Prior to this, we were capturing the caller frame, which is completely irrelevant to the generator frame.
2021-11-11 00:34:44 +03:30
};
LibJS: Make Value() default-construct the undefined value The special empty value (that we use for array holes, Optional<Value> when empty and a few other other placeholder/sentinel tasks) still exists, but you now create one via JS::js_special_empty_value() and check for it with Value::is_special_empty_value(). The main idea here is to make it very unlikely to accidentally create an unexpected special empty value.
2025-04-04 23:16:34 +02:00
ResultAndReturnRegister run_executable(Bytecode::Executable&, Optional<size_t> entry_point, Value initial_accumulator_value = js_special_empty_value());
LibJS: Start fleshing out a bytecode for the JavaScript engine :^) This patch begins the work of implementing JavaScript execution in a bytecode VM instead of an AST tree-walk interpreter. It's probably quite naive, but we have to start somewhere. The basic idea is that you call Bytecode::Generator::generate() on an AST node and it hands you back a Bytecode::Block filled with instructions that can then be interpreted by a Bytecode::Interpreter. This first version only implements two instructions: Load and Add. :^) Each bytecode block has infinity registers, and the interpreter resizes its register file to fit the block being executed. Two new `js` options are added in this patch as well: `-d` will dump the generated bytecode `-b` will execute the generated bytecode Note that unless `-d` and/or `-b` are specified, none of the bytecode related stuff in LibJS runs at all. This is implemented in parallel with the existing AST interpreter. :^)
2021-06-03 10:46:30 +02:00
LibJS: Introduce an accumulator register to Bytecode::Interpreter This commit introduces the concept of an accumulator register to LibJS's bytecode interpreter. The accumulator register is always register 0, and most simple instructions use it for reading and writing. Not only does this slim down the AST, but it also simplifies a lot of the code. For example, the generate_bytecode methods no longer need to return an Optional<Register>, as any opcode which has a "return" value will always put it into the accumulator. This also renames the old Op::Load to Op::LoadImmediate, and uses Op::Load to load from a register into the accumulator. There is also an Op::Store to put the value in the accumulator into another register.
2021-06-07 20:58:36 -07:00
ALWAYS_INLINE Value& accumulator() { return reg(Register::accumulator()); }
LibJS/Bytecode: Keep saved return value in call frame register This fixes an issue where returning inside a `try` block and then calling a function inside `finally` would clobber the saved return value from the `try` block. Note that we didn't need to change the base of register allocation, since it was already 1 too high. With this fixed, https://microsoft.com/edge loads in bytecode mode. :^) Thanks to Luke for reducing the issue!
2023-07-21 17:30:07 +02:00
ALWAYS_INLINE Value& saved_return_value() { return reg(Register::saved_return_value()); }
LibJS: Merge CallFrame into ExecutionContext Before this change both ExecutionContext and CallFrame were created before executing function/module/script with a couple exceptions: - executable created for default function argument evaluation has to run in function's execution context. - `execute_ast_node()` where executable compiled for ASTNode has to be executed in running execution context. This change moves all members previously owned by CallFrame into ExecutionContext, and makes two exceptions where an executable that does not have a corresponding execution context saves and restores registers before running. Now, all execution state lives in a single entity, which makes it a bit easier to reason about and opens opportunities for optimizations, such as moving registers and local variables into a single array.
2024-05-01 19:33:49 +02:00
Value& reg(Register const& r)
{
LibJS: Join locals, constants and registers into single vector Merging registers, constants and locals into single vector means: - Better data locality - No need to check type in Interpreter::get() and Interpreter::set() which are very hot functions Performance improvement is visible in almost all Octane and Kraken tests.
2024-05-12 18:49:03 +02:00
return m_registers_and_constants_and_locals.data()[r.index()];
LibJS: Merge CallFrame into ExecutionContext Before this change both ExecutionContext and CallFrame were created before executing function/module/script with a couple exceptions: - executable created for default function argument evaluation has to run in function's execution context. - `execute_ast_node()` where executable compiled for ASTNode has to be executed in running execution context. This change moves all members previously owned by CallFrame into ExecutionContext, and makes two exceptions where an executable that does not have a corresponding execution context saves and restores registers before running. Now, all execution state lives in a single entity, which makes it a bit easier to reason about and opens opportunities for optimizations, such as moving registers and local variables into a single array.
2024-05-01 19:33:49 +02:00
}
Value reg(Register const& r) const
{
LibJS: Join locals, constants and registers into single vector Merging registers, constants and locals into single vector means: - Better data locality - No need to check type in Interpreter::get() and Interpreter::set() which are very hot functions Performance improvement is visible in almost all Octane and Kraken tests.
2024-05-12 18:49:03 +02:00
return m_registers_and_constants_and_locals.data()[r.index()];
LibJS: Merge CallFrame into ExecutionContext Before this change both ExecutionContext and CallFrame were created before executing function/module/script with a couple exceptions: - executable created for default function argument evaluation has to run in function's execution context. - `execute_ast_node()` where executable compiled for ASTNode has to be executed in running execution context. This change moves all members previously owned by CallFrame into ExecutionContext, and makes two exceptions where an executable that does not have a corresponding execution context saves and restores registers before running. Now, all execution state lives in a single entity, which makes it a bit easier to reason about and opens opportunities for optimizations, such as moving registers and local variables into a single array.
2024-05-01 19:33:49 +02:00
}
LibJS/Bytecode: Add Bytecode::Operand An Operand is either a register, a local, or a constant (index into the executable's constant table)
2024-02-02 10:19:17 +01:00
[[nodiscard]] Value get(Operand) const;
void set(Operand, Value);
LibJS: Implement generator functions (only in bytecode mode)
2021-06-11 01:38:30 +04:30
LibJS: Prepare yield object before re-routing it through finally
2024-05-18 17:25:43 +02:00
Value do_yield(Value value, Optional<Label> continuation);
LibJS: Keep return value in a call frame register
2023-09-26 15:32:46 +02:00
void do_return(Value value)
LibJS: Align codegen AwaitExpressions to YieldExpressions We use generators in bytecode to approximate async functions, but the code generated by AwaitExpressions did not have the value processing paths that Yield requires, eg the `generator.throw()` path, which is used by AsyncFunctionDriverWrapper to signal Promise rejections.
2022-12-25 17:15:29 +01:00
{
LibJS: Keep return value in a call frame register
2023-09-26 15:32:46 +02:00
reg(Register::return_value()) = value;
LibJS: Make Value() default-construct the undefined value The special empty value (that we use for array holes, Optional<Value> when empty and a few other other placeholder/sentinel tasks) still exists, but you now create one via JS::js_special_empty_value() and check for it with Value::is_special_empty_value(). The main idea here is to make it very unlikely to accidentally create an unexpected special empty value.
2025-04-04 23:16:34 +02:00
reg(Register::exception()) = js_special_empty_value();
LibJS: Align codegen AwaitExpressions to YieldExpressions We use generators in bytecode to approximate async functions, but the code generated by AwaitExpressions did not have the value processing paths that Yield requires, eg the `generator.throw()` path, which is used by AsyncFunctionDriverWrapper to signal Promise rejections.
2022-12-25 17:15:29 +01:00
}
LibJS: Add basic support for while loops in the bytecode engine This introduces two new instructions: Jump and JumpIfFalse. Jumps are made to a Bytecode::Label, which is a simple object that represents a location in the bytecode stream. Note that you may not always know the target of a jump when adding the jump instruction itself, but we can just update the instruction later on during codegen once we know where the jump target is. The Bytecode::Interpreter now implements jumping via a jump slot that gets checked after each instruction to see if a jump is pending. If not, we just increment the PC as usual.
2021-06-04 12:07:38 +02:00
LibJS: Use static unwind mappings for unwind related functions
2023-10-20 00:33:51 +02:00
void enter_unwind_context();
LibJS: Implement bytecode generation for try..catch..finally EnterUnwindContext pushes an unwind context (exception handler and/or finalizer) onto a stack. LeaveUnwindContext pops the unwind context from that stack. Upon return to the interpreter loop we check whether the VM has an exception pending. If no unwind context is available we return from the loop. If an exception handler is available we clear the VM's exception, put the exception value into the accumulator register, clear the unwind context's handler and jump to the handler. If no handler is available but a finalizer is available we save the exception value + metadata (for later use by ContinuePendingUnwind), clear the VM's exception, pop the unwind context and jump to the finalizer. ContinuePendingUnwind checks whether a saved exception is available. If no saved exception is available it jumps to the resume label. Otherwise it stores the exception into the VM. The Jump after LeaveUnwindContext could be integrated into the LeaveUnwindContext instruction. I've kept them separate for now to make the bytecode more readable. > try { 1; throw "x" } catch (e) { 2 } finally { 3 }; 4 1: [ 0] EnterScope [ 10] EnterUnwindContext handler:@4 finalizer:@3 [ 38] EnterScope [ 48] LoadImmediate 1 [ 60] NewString 1 ("x") [ 70] Throw <for non-terminated blocks: insert LeaveUnwindContext + Jump @3 here> 2: [ 0] LoadImmediate 4 3: [ 0] EnterScope [ 10] LoadImmediate 3 [ 28] ContinuePendingUnwind resume:@2 4: [ 0] SetVariable 0 (e) [ 10] EnterScope [ 20] LoadImmediate 2 [ 38] LeaveUnwindContext [ 3c] Jump @3 String Table: 0: e 1: x
2021-06-10 15:04:38 +02:00
void leave_unwind_context();
LibJS/Bytecode: Move to a new bytecode format This patch moves us away from the accumulator-based bytecode format to one with explicit source and destination registers. The new format has multiple benefits: - ~25% faster on the Kraken and Octane benchmarks :^) - Fewer instructions to accomplish the same thing - Much easier for humans to read(!) Because this change requires a fundamental shift in how bytecode is generated, it is quite comprehensive. Main implementation mechanism: generate_bytecode() virtual function now takes an optional "preferred dst" operand, which allows callers to communicate when they have an operand that would be optimal for the result to go into. It also returns an optional "actual dst" operand, which is where the completion value (if any) of the AST node is stored after the node has "executed". One thing of note that's new: because instructions can now take locals as operands, this means we got rid of the GetLocal instruction. A side-effect of that is we have to think about the temporal deadzone (TDZ) a bit differently for locals (GetLocal would previously check for empty values and interpret that as a TDZ access and throw). We now insert special ThrowIfTDZ instructions in places where a local access may be in the TDZ, to maintain the correct behavior. There are a number of progressions and regressions from this test: A number of async generator tests have been accidentally fixed while converting the implementation to the new bytecode format. It didn't seem useful to preserve bugs in the original code when converting it. Some "does eval() return the correct completion value" tests have regressed, in particular ones related to propagating the appropriate completion after control flow statements like continue and break. These are all fairly obscure issues, and I believe we can continue working on them separately. The net test262 result is a progression though. :^)
2024-02-04 08:00:54 +01:00
void catch_exception(Operand dst);
LibJS: Restore scheduled jumps in catch blocks without finalizers
2024-04-11 11:07:35 +02:00
void restore_scheduled_jump();
LibJS: Cleanup unwind state when transferring control out of a finalizer This does two things: * Clear exceptions when transferring control out of a finalizer Otherwise they would resurface at the end of the next finalizer (see test the new test case), or at the end of a function * Pop one scheduled jump when transferring control out of a finalizer This removes one old FIXME
2024-04-11 11:58:18 +02:00
void leave_finally();
LibJS: Implement bytecode generation for try..catch..finally EnterUnwindContext pushes an unwind context (exception handler and/or finalizer) onto a stack. LeaveUnwindContext pops the unwind context from that stack. Upon return to the interpreter loop we check whether the VM has an exception pending. If no unwind context is available we return from the loop. If an exception handler is available we clear the VM's exception, put the exception value into the accumulator register, clear the unwind context's handler and jump to the handler. If no handler is available but a finalizer is available we save the exception value + metadata (for later use by ContinuePendingUnwind), clear the VM's exception, pop the unwind context and jump to the finalizer. ContinuePendingUnwind checks whether a saved exception is available. If no saved exception is available it jumps to the resume label. Otherwise it stores the exception into the VM. The Jump after LeaveUnwindContext could be integrated into the LeaveUnwindContext instruction. I've kept them separate for now to make the bytecode more readable. > try { 1; throw "x" } catch (e) { 2 } finally { 3 }; 4 1: [ 0] EnterScope [ 10] EnterUnwindContext handler:@4 finalizer:@3 [ 38] EnterScope [ 48] LoadImmediate 1 [ 60] NewString 1 ("x") [ 70] Throw <for non-terminated blocks: insert LeaveUnwindContext + Jump @3 here> 2: [ 0] LoadImmediate 4 3: [ 0] EnterScope [ 10] LoadImmediate 3 [ 28] ContinuePendingUnwind resume:@2 4: [ 0] SetVariable 0 (e) [ 10] EnterScope [ 20] LoadImmediate 2 [ 38] LeaveUnwindContext [ 3c] Jump @3 String Table: 0: e 1: x
2021-06-10 15:04:38 +02:00
LibJS/JIT: Support the EnterObjectEnvironment bytecode instruction We can now use `with` statements in jitted code. :^)
2023-11-12 00:12:21 +01:00
void enter_object_environment(Object&);
LibJS/Bytecode: Cache object own property accesses The instructions GetById and GetByIdWithThis now remember the last-seen Shape, and if we see the same object again, we reuse the property offset from last time without doing a new lookup. This allows us to use Object::get_direct(), bypassing the entire lookup machinery and saving lots of time. ~23% speed-up on Kraken/ai-astar.js :^)
2023-07-08 17:43:26 +02:00
Executable& current_executable() { return *m_current_executable; }
Executable const& current_executable() const { return *m_current_executable; }
LibJS/Bytecode: Flatten bytecode to a contiguous representation Instead of keeping bytecode as a set of disjoint basic blocks on the malloc heap, bytecode is now a contiguous sequence of bytes(!) The transformation happens at the end of Bytecode::Generator::generate() and the only really hairy part is rerouting jump labels. This required solving a few problems: - The interpreter execution loop had to change quite a bit, since we were storing BasicBlock pointers all over the place, and control transfer was done by redirecting the interpreter's current block. - Exception handlers & finalizers are now stored per-bytecode-range in a side table in Executable. - The interpreter now has a plain program counter instead of a stream iterator. This actually makes error stack generation a bit nicer since we just have to deal with a number instead of reaching into the iterator. This yields a 25% performance improvement on this microbenchmark: for (let i = 0; i < 1_000_000; ++i) { } But basically everything gets faster. :^)
2024-05-06 06:44:08 +02:00
Optional<size_t> program_counter() const { return m_program_counter; }
LibJS: Share argument values buffer between calls This buffer is being created and then immediately destroyed, let's reuse it to reduce memory allocations.
2024-10-31 22:46:44 +01:00
Span<Value> allocate_argument_values(size_t argument_count)
{
m_argument_values_buffer.resize_and_keep_capacity(argument_count);
return m_argument_values_buffer.span();
}
LibJS: Store strings in a string table Instead of using Strings in the bytecode ops this adds a global string table to the Executable struct which individual operations can refer to using indices. This brings bytecode ops one step closer to being pointer free.
2021-06-09 10:02:01 +02:00
LibJS/Bytecode: Cache the running execution context in interpreter
2024-05-11 18:16:27 +02:00
ExecutionContext& running_execution_context() { return *m_running_execution_context; }
LibJS: Start fleshing out a bytecode for the JavaScript engine :^) This patch begins the work of implementing JavaScript execution in a bytecode VM instead of an AST tree-walk interpreter. It's probably quite naive, but we have to start somewhere. The basic idea is that you call Bytecode::Generator::generate() on an AST node and it hands you back a Bytecode::Block filled with instructions that can then be interpreted by a Bytecode::Interpreter. This first version only implements two instructions: Load and Add. :^) Each bytecode block has infinity registers, and the interpreter resizes its register file to fit the block being executed. Two new `js` options are added in this patch as well: `-d` will dump the generated bytecode `-b` will execute the generated bytecode Note that unless `-d` and/or `-b` are specified, none of the bytecode related stuff in LibJS runs at all. This is implemented in parallel with the existing AST interpreter. :^)
2021-06-03 10:46:30 +02:00
private:
LibJS/Bytecode: Flatten bytecode to a contiguous representation Instead of keeping bytecode as a set of disjoint basic blocks on the malloc heap, bytecode is now a contiguous sequence of bytes(!) The transformation happens at the end of Bytecode::Generator::generate() and the only really hairy part is rerouting jump labels. This required solving a few problems: - The interpreter execution loop had to change quite a bit, since we were storing BasicBlock pointers all over the place, and control transfer was done by redirecting the interpreter's current block. - Exception handlers & finalizers are now stored per-bytecode-range in a side table in Executable. - The interpreter now has a plain program counter instead of a stream iterator. This actually makes error stack generation a bit nicer since we just have to deal with a number instead of reaching into the iterator. This yields a 25% performance improvement on this microbenchmark: for (let i = 0; i < 1_000_000; ++i) { } But basically everything gets faster. :^)
2024-05-06 06:44:08 +02:00
void run_bytecode(size_t entry_point);
enum class HandleExceptionResponse {
ExitFromExecutable,
ContinueInThisExecutable,
};
[[nodiscard]] HandleExceptionResponse handle_exception(size_t& program_counter, Value exception);
LibJS: Move bytecode interpreter's inner loop to its own function
2023-09-26 16:41:42 +02:00
LibJS: Add a VM accessor to Bytecode::Interpreter :^)
2021-06-03 18:26:13 +02:00
VM& m_vm;
LibJS/Bytecode: Flatten bytecode to a contiguous representation Instead of keeping bytecode as a set of disjoint basic blocks on the malloc heap, bytecode is now a contiguous sequence of bytes(!) The transformation happens at the end of Bytecode::Generator::generate() and the only really hairy part is rerouting jump labels. This required solving a few problems: - The interpreter execution loop had to change quite a bit, since we were storing BasicBlock pointers all over the place, and control transfer was done by redirecting the interpreter's current block. - Exception handlers & finalizers are now stored per-bytecode-range in a side table in Executable. - The interpreter now has a plain program counter instead of a stream iterator. This actually makes error stack generation a bit nicer since we just have to deal with a number instead of reaching into the iterator. This yields a 25% performance improvement on this microbenchmark: for (let i = 0; i < 1_000_000; ++i) { } But basically everything gets faster. :^)
2024-05-06 06:44:08 +02:00
Optional<size_t> m_scheduled_jump;
LibGC+Everywhere: Factor out a LibGC from LibJS Resulting in a massive rename across almost everywhere! Alongside the namespace change, we now have the following names: * JS::NonnullGCPtr -> GC::Ref * JS::GCPtr -> GC::Ptr * JS::HeapFunction -> GC::Function * JS::CellImpl -> GC::Cell * JS::Handle -> GC::Root
2024-11-15 04:01:23 +13:00
GC::Ptr<Executable> m_current_executable { nullptr };
GC::Ptr<Realm> m_realm { nullptr };
GC::Ptr<Object> m_global_object { nullptr };
GC::Ptr<DeclarativeEnvironment> m_global_declarative_environment { nullptr };
LibJS/Bytecode: Flatten bytecode to a contiguous representation Instead of keeping bytecode as a set of disjoint basic blocks on the malloc heap, bytecode is now a contiguous sequence of bytes(!) The transformation happens at the end of Bytecode::Generator::generate() and the only really hairy part is rerouting jump labels. This required solving a few problems: - The interpreter execution loop had to change quite a bit, since we were storing BasicBlock pointers all over the place, and control transfer was done by redirecting the interpreter's current block. - Exception handlers & finalizers are now stored per-bytecode-range in a side table in Executable. - The interpreter now has a plain program counter instead of a stream iterator. This actually makes error stack generation a bit nicer since we just have to deal with a number instead of reaching into the iterator. This yields a 25% performance improvement on this microbenchmark: for (let i = 0; i < 1_000_000; ++i) { } But basically everything gets faster. :^)
2024-05-06 06:44:08 +02:00
Optional<size_t&> m_program_counter;
LibJS: Emit bytecode for function declaration instantiation By doing that all instructions required for instantiation are emitted once in compilation and then reused for subsequent calls, instead of running generic instantiation process for each call.
2024-05-05 22:06:55 +02:00
Span<Value> m_arguments;
LibJS: Join locals, constants and registers into single vector Merging registers, constants and locals into single vector means: - Better data locality - No need to check type in Interpreter::get() and Interpreter::set() which are very hot functions Performance improvement is visible in almost all Octane and Kraken tests.
2024-05-12 18:49:03 +02:00
Span<Value> m_registers_and_constants_and_locals;
LibJS: Share argument values buffer between calls This buffer is being created and then immediately destroyed, let's reuse it to reduce memory allocations.
2024-10-31 22:46:44 +01:00
Vector<Value> m_argument_values_buffer;
LibJS/Bytecode: Cache the running execution context in interpreter
2024-05-11 18:16:27 +02:00
ExecutionContext* m_running_execution_context { nullptr };
LibJS: Start fleshing out a bytecode for the JavaScript engine :^) This patch begins the work of implementing JavaScript execution in a bytecode VM instead of an AST tree-walk interpreter. It's probably quite naive, but we have to start somewhere. The basic idea is that you call Bytecode::Generator::generate() on an AST node and it hands you back a Bytecode::Block filled with instructions that can then be interpreted by a Bytecode::Interpreter. This first version only implements two instructions: Load and Add. :^) Each bytecode block has infinity registers, and the interpreter resizes its register file to fit the block being executed. Two new `js` options are added in this patch as well: `-d` will dump the generated bytecode `-b` will execute the generated bytecode Note that unless `-d` and/or `-b` are specified, none of the bytecode related stuff in LibJS runs at all. This is implemented in parallel with the existing AST interpreter. :^)
2021-06-03 10:46:30 +02:00
};
LibJS: Move global "should dump bytecode" flag into LibJS This will allow us to trigger bytecode executable dumps when generating bytecode inside LibJS as well, not just in clients like js and test-js.
2021-10-24 13:34:46 +02:00
extern bool g_dump_bytecode;
LibJS: Use FlyString in PropertyKey instead of DeprecatedFlyString This required dealing with *substantial* fallout.
2025-03-18 18:08:02 -05:00
ThrowCompletionOr<GC::Ref<Bytecode::Executable>> compile(VM&, ASTNode const&, JS::FunctionKind kind, FlyString const& name);
LibGC+Everywhere: Factor out a LibGC from LibJS Resulting in a massive rename across almost everywhere! Alongside the namespace change, we now have the following names: * JS::NonnullGCPtr -> GC::Ref * JS::GCPtr -> GC::Ptr * JS::HeapFunction -> GC::Function * JS::CellImpl -> GC::Cell * JS::Handle -> GC::Root
2024-11-15 04:01:23 +13:00
ThrowCompletionOr<GC::Ref<Bytecode::Executable>> compile(VM&, ECMAScriptFunctionObject const&);
LibJS/Bytecode: Simplify Bytecode::Interpreter lifetime model The JS::VM now owns the one Bytecode::Interpreter. We no longer have multiple bytecode interpreters, and there is no concept of a "current" bytecode interpreter. If you ask for VM::bytecode_interpreter_if_exists(), it will return null if we're not running the program in "bytecode enabled" mode. If you ask for VM::bytecode_interpreter(), it will return a bytecode interpreter in all modes. This is used for situations where even the AST interpreter switches to bytecode mode (generators, etc.)
2023-06-22 15:59:18 +02:00
LibJS: Start fleshing out a bytecode for the JavaScript engine :^) This patch begins the work of implementing JavaScript execution in a bytecode VM instead of an AST tree-walk interpreter. It's probably quite naive, but we have to start somewhere. The basic idea is that you call Bytecode::Generator::generate() on an AST node and it hands you back a Bytecode::Block filled with instructions that can then be interpreted by a Bytecode::Interpreter. This first version only implements two instructions: Load and Add. :^) Each bytecode block has infinity registers, and the interpreter resizes its register file to fit the block being executed. Two new `js` options are added in this patch as well: `-d` will dump the generated bytecode `-b` will execute the generated bytecode Note that unless `-d` and/or `-b` are specified, none of the bytecode related stuff in LibJS runs at all. This is implemented in parallel with the existing AST interpreter. :^)
2021-06-03 10:46:30 +02:00
}
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