mirror of
https://github.com/LadybirdBrowser/ladybird.git
synced 2025-05-02 09:18:52 +00:00
f6aee2b9e8
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. :^)
58 lines
1.5 KiB
C++
58 lines
1.5 KiB
C++
/*
|
|
* Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
|
|
*
|
|
* SPDX-License-Identifier: BSD-2-Clause
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <AK/Badge.h>
|
|
#include <AK/String.h>
|
|
#include <LibJS/Forward.h>
|
|
#include <LibJS/Heap/Handle.h>
|
|
|
|
namespace JS::Bytecode {
|
|
|
|
struct UnwindInfo {
|
|
JS::GCPtr<Executable const> executable;
|
|
JS::GCPtr<Environment> lexical_environment;
|
|
|
|
bool handler_called { false };
|
|
};
|
|
|
|
class BasicBlock {
|
|
AK_MAKE_NONCOPYABLE(BasicBlock);
|
|
|
|
public:
|
|
static NonnullOwnPtr<BasicBlock> create(String name);
|
|
~BasicBlock();
|
|
|
|
ReadonlyBytes instruction_stream() const { return m_buffer.span(); }
|
|
u8* data() { return m_buffer.data(); }
|
|
u8 const* data() const { return m_buffer.data(); }
|
|
size_t size() const { return m_buffer.size(); }
|
|
|
|
void grow(size_t additional_size);
|
|
|
|
void terminate(Badge<Generator>) { m_terminated = true; }
|
|
bool is_terminated() const { return m_terminated; }
|
|
|
|
String const& name() const { return m_name; }
|
|
|
|
void set_handler(BasicBlock const& handler) { m_handler = &handler; }
|
|
void set_finalizer(BasicBlock const& finalizer) { m_finalizer = &finalizer; }
|
|
|
|
BasicBlock const* handler() const { return m_handler; }
|
|
BasicBlock const* finalizer() const { return m_finalizer; }
|
|
|
|
private:
|
|
explicit BasicBlock(String name);
|
|
|
|
Vector<u8> m_buffer;
|
|
BasicBlock const* m_handler { nullptr };
|
|
BasicBlock const* m_finalizer { nullptr };
|
|
String m_name;
|
|
bool m_terminated { false };
|
|
};
|
|
|
|
}
|