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ladybird/Userland/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. :^)
2021-06-03 10:46:30 +02:00
/*
* Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
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.
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#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
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#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/Bytecode: Rename RegisterWindow to CallFrame This is a better name for what it actually represents.
2023-07-20 10:46:42 +02:00
struct CallFrame {
LibJS/Bytecode: Make Bytecode::Interpreter participate in GC marking Since the relationship between VM and Bytecode::Interpreter is now clear, we can have VM ask the Interpreter for roots in the GC marking pass. This avoids having to register and unregister handles and MarkedVectors over and over. Since GeneratorObject can also own a RegisterWindow, we share the code in a RegisterWindow::visit_edges() helper. ~4% speed-up on Kraken/stanford-crypto-ccm.js :^)
2023-07-02 12:53:10 +02:00
void visit_edges(Cell::Visitor& visitor)
{
for (auto const& value : registers)
visitor.visit(value);
for (auto const& environment : saved_lexical_environments)
visitor.visit(environment);
for (auto& context : unwind_contexts) {
visitor.visit(context.lexical_environment);
}
}
Vector<Value> registers;
Vector<GCPtr<Environment>> saved_lexical_environments;
LibJS/Bytecode: Store unwind contexts inside RegisterWindow Unwind contexts need to be preserved as we exit and re-enter a generator. For example, this would previously crash when returning from the try statement after yielding as we lost the unwind context when yielding, but still have a LeaveUnwindContext instruction from running `perform_needed_unwinds` when generating the return statement. ```js function* a() { try { return (yield 1); } catch {} } iter = a(); iter.next(); iter.next(); ```
2022-11-25 23:15:44 +00:00
Vector<UnwindInfo> unwind_contexts;
LibJS: More properly implement scoping rules in bytecode codegen Now we emit CreateVariable and SetVariable with the appropriate initialization/environment modes, much closer to the spec. This makes a whole lot of things like let/const variables, function and variable hoisting and some other things work :^)
2022-02-12 19:48:45 +03:30
};
LibJS: Compile ScriptFunctions into bytecode and run them that way :^) If there's a current Bytecode::Interpreter in action, ScriptFunction will now compile itself into bytecode and execute in that context. This patch also adds the Return bytecode instruction so that we can actually return values from called functions. :^) Return values are propagated from callee to caller via the caller's $0 register. Bytecode::Interpreter now keeps a stack of register "windows". These are not very efficient, but it should be pretty straightforward to convert them to e.g a sliding register window architecture later on. This is pretty dang cool! :^)
2021-06-05 15:53:36 +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
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. :^)
2021-06-03 10:46:30 +02:00
~Interpreter();
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
Realm& realm();
LibJS: Add a VM accessor to Bytecode::Interpreter :^)
2021-06-03 18:26:13 +02:00
VM& vm() { 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
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(Script&, JS::GCPtr<Environment> lexical_environment_override = nullptr);
ThrowCompletionOr<Value> run(SourceTextModule&);
LibJS: Remove unused realm parameter from run_and_return_frame()
2023-09-21 09:26:32 +02:00
ThrowCompletionOr<Value> run(Bytecode::Executable& executable, Bytecode::BasicBlock const* entry_point = nullptr)
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: Remove unused realm parameter from run_and_return_frame()
2023-09-21 09:26:32 +02:00
auto value_and_frame = run_and_return_frame(executable, entry_point);
LibJS: Implement the NewClass opcode
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return move(value_and_frame.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
}
struct ValueAndFrame {
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/Bytecode: Rename RegisterWindow to CallFrame This is a better name for what it actually represents.
2023-07-20 10:46:42 +02:00
OwnPtr<CallFrame> frame;
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: Remove unused realm parameter from run_and_return_frame()
2023-09-21 09:26:32 +02:00
ValueAndFrame run_and_return_frame(Bytecode::Executable&, Bytecode::BasicBlock const* entry_point, CallFrame* = 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: 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: Compile ScriptFunctions into bytecode and run them that way :^) If there's a current Bytecode::Interpreter in action, ScriptFunction will now compile itself into bytecode and execute in that context. This patch also adds the Return bytecode instruction so that we can actually return values from called functions. :^) Return values are propagated from callee to caller via the caller's $0 register. Bytecode::Interpreter now keeps a stack of register "windows". These are not very efficient, but it should be pretty straightforward to convert them to e.g a sliding register window architecture later on. This is pretty dang cool! :^)
2021-06-05 15:53:36 +02:00
Value& reg(Register const& r) { return registers()[r.index()]; }
LibJS: Implement generator functions (only in bytecode mode)
2021-06-11 01:38:30 +04:30
LibJS/Bytecode: Rename RegisterWindow to CallFrame This is a better name for what it actually represents.
2023-07-20 10:46:42 +02:00
auto& saved_lexical_environment_stack() { return call_frame().saved_lexical_environments; }
auto& unwind_contexts() { return call_frame().unwind_contexts; }
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: Generate bytecode in basic blocks instead of one big block This limits the size of each block (currently set to 1K), and gets us closer to a canonical, more easily analysable bytecode format. As a result of this, "Labels" are now simply entries to basic blocks. Since there is no more 'conditional' jump (as all jumps are always taken), JumpIf{True,False} are unified to JumpConditional, and JumpIfNullish is renamed to JumpNullish. Also fixes #7914 as a result of reimplementing the loop logic.
2021-06-09 06:49:58 +04:30
void jump(Label const& label)
{
m_pending_jump = &label.block();
}
LibJS: Generate unwind chains for break in Bytecode This uses a newly added instruction `ScheduleJump` This instruction tells the finally proceeding it, that instead of jumping to it's next block it should jump to the designated block.
2022-11-25 16:15:34 +01:00
void schedule_jump(Label const& label)
{
m_scheduled_jump = &label.block();
VERIFY(unwind_contexts().last().finalizer);
jump(Label { *unwind_contexts().last().finalizer });
}
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
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reg(Register::return_value()) = value;
LibJS: Keep current exception in a call frame register Instead of keeping it in a Bytecode::Interpreter member, move it into a dedicated call frame register.
2023-09-26 11:57:42 +02:00
reg(Register::exception()) = {};
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: 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 enter_unwind_context(Optional<Label> handler_target, Optional<Label> finalizer_target);
void leave_unwind_context();
LibJS: Convert Instruction::execute in bytecode to ThrowCompletionOr This allows us to use TRY in these functions :^).
2022-02-07 14:36:45 +01:00
ThrowCompletionOr<void> continue_pending_unwind(Label const& resume_label);
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/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: Expose some information about the bytecode interpreters state This is quite helpful, when reporting internal errors.
2022-10-30 11:58:46 +01:00
BasicBlock const& current_block() const { return *m_current_block; }
LibJS: Add file & line number to bytecode VM stack traces :^) This works by adding source start/end offset to every bytecode instruction. In the future we can make this more efficient by keeping a map of bytecode ranges to source ranges in the Executable instead, but let's just get traces working first. Co-Authored-By: Andrew Kaster <akaster@serenityos.org>
2023-09-01 16:53:55 +02:00
auto& instruction_stream_iterator() const { return m_pc; }
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: Make Bytecode::Interpreter participate in GC marking Since the relationship between VM and Bytecode::Interpreter is now clear, we can have VM ask the Interpreter for roots in the GC marking pass. This avoids having to register and unregister handles and MarkedVectors over and over. Since GeneratorObject can also own a RegisterWindow, we share the code in a RegisterWindow::visit_edges() helper. ~4% speed-up on Kraken/stanford-crypto-ccm.js :^)
2023-07-02 12:53:10 +02:00
void visit_edges(Cell::Visitor&);
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: Rename RegisterWindow to CallFrame This is a better name for what it actually represents.
2023-07-20 10:46:42 +02:00
CallFrame& call_frame()
LibJS: Avoid copying the frame into the interpreter in BC generators
2022-04-15 20:20:51 +04:30
{
LibJS/Bytecode: Rename RegisterWindow to CallFrame This is a better name for what it actually represents.
2023-07-20 10:46:42 +02:00
return m_call_frames.last().visit([](auto& x) -> CallFrame& { return *x; });
LibJS: Avoid copying the frame into the interpreter in BC generators
2022-04-15 20:20:51 +04:30
}
LibJS/Bytecode: Rename RegisterWindow to CallFrame This is a better name for what it actually represents.
2023-07-20 10:46:42 +02:00
CallFrame const& call_frame() const
LibJS: Avoid copying the frame into the interpreter in BC generators
2022-04-15 20:20:51 +04:30
{
LibJS/Bytecode: Rename RegisterWindow to CallFrame This is a better name for what it actually represents.
2023-07-20 10:46:42 +02:00
return const_cast<Interpreter*>(this)->call_frame();
LibJS: Avoid copying the frame into the interpreter in BC generators
2022-04-15 20:20:51 +04:30
}
LibJS/Bytecode: Rename RegisterWindow to CallFrame This is a better name for what it actually represents.
2023-07-20 10:46:42 +02:00
Span<Value> registers() { return m_current_call_frame; }
ReadonlySpan<Value> registers() const { return m_current_call_frame; }
LibJS/Bytecode: Store current interpreter register window as a Span This avoids a bunch of indirections on every single register access. ~17% speed-up on Kraken/stanford-crypto-aes.js :^)
2023-07-01 13:56:40 +02:00
LibJS/Bytecode: Rename RegisterWindow to CallFrame This is a better name for what it actually represents.
2023-07-20 10:46:42 +02:00
void push_call_frame(Variant<NonnullOwnPtr<CallFrame>, CallFrame*>, size_t register_count);
[[nodiscard]] Variant<NonnullOwnPtr<CallFrame>, CallFrame*> pop_call_frame();
LibJS: Compile ScriptFunctions into bytecode and run them that way :^) If there's a current Bytecode::Interpreter in action, ScriptFunction will now compile itself into bytecode and execute in that context. This patch also adds the Return bytecode instruction so that we can actually return values from called functions. :^) Return values are propagated from callee to caller via the caller's $0 register. Bytecode::Interpreter now keeps a stack of register "windows". These are not very efficient, but it should be pretty straightforward to convert them to e.g a sliding register window architecture later on. This is pretty dang cool! :^)
2021-06-05 15:53:36 +02:00
LibJS: Add a VM accessor to Bytecode::Interpreter :^)
2021-06-03 18:26:13 +02:00
VM& m_vm;
LibJS/Bytecode: Rename RegisterWindow to CallFrame This is a better name for what it actually represents.
2023-07-20 10:46:42 +02:00
Vector<Variant<NonnullOwnPtr<CallFrame>, CallFrame*>> m_call_frames;
Span<Value> m_current_call_frame;
LibJS: Generate bytecode in basic blocks instead of one big block This limits the size of each block (currently set to 1K), and gets us closer to a canonical, more easily analysable bytecode format. As a result of this, "Labels" are now simply entries to basic blocks. Since there is no more 'conditional' jump (as all jumps are always taken), JumpIf{True,False} are unified to JumpConditional, and JumpIfNullish is renamed to JumpNullish. Also fixes #7914 as a result of reimplementing the loop logic.
2021-06-09 06:49:58 +04:30
Optional<BasicBlock const*> m_pending_jump;
LibJS: Generate unwind chains for break in Bytecode This uses a newly added instruction `ScheduleJump` This instruction tells the finally proceeding it, that instead of jumping to it's next block it should jump to the designated block.
2022-11-25 16:15:34 +01:00
BasicBlock const* m_scheduled_jump { nullptr };
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* m_current_executable { nullptr };
LibJS: Expose some information about the bytecode interpreters state This is quite helpful, when reporting internal errors.
2022-10-30 11:58:46 +01:00
BasicBlock const* m_current_block { nullptr };
LibJS: Add file & line number to bytecode VM stack traces :^) This works by adding source start/end offset to every bytecode instruction. In the future we can make this more efficient by keeping a map of bytecode ranges to source ranges in the Executable instead, but let's just get traces working first. Co-Authored-By: Andrew Kaster <akaster@serenityos.org>
2023-09-01 16:53:55 +02:00
Optional<InstructionStreamIterator&> m_pc {};
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/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
ThrowCompletionOr<NonnullOwnPtr<Bytecode::Executable>> compile(VM&, ASTNode const& no, JS::FunctionKind kind, DeprecatedFlyString const& name);
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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