ladybird/Libraries/LibJS/Bytecode/BasicBlock.h
Andreas Kling 81bee185e6 LibJS: Replace source map HashMap with sorted Vector
Bytecode source map entries are always added in order of increasing
bytecode offset, and lookups only happen during error handling (a cold
path). This makes a sorted vector with binary search a better fit than
a hash map.

This change reduces memory overhead and speeds up bytecode generation
by avoiding hash table operations during compilation. Lookups remain
fast via binary search, and since source_range_at() is only called
when generating stack traces, the O(log n) lookup is acceptable.
2026-01-26 19:37:42 +01:00

83 lines
2.4 KiB
C++

/*
* Copyright (c) 2021, Andreas Kling <andreas@ladybird.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Badge.h>
#include <AK/String.h>
#include <LibGC/Root.h>
#include <LibJS/Bytecode/Executable.h>
#include <LibJS/Bytecode/ScopedOperand.h>
#include <LibJS/Forward.h>
namespace JS::Bytecode {
struct UnwindInfo {
GC::Ptr<Executable const> executable;
GC::Ptr<Environment> lexical_environment;
bool handler_called { false };
};
class BasicBlock {
AK_MAKE_NONCOPYABLE(BasicBlock);
public:
static NonnullOwnPtr<BasicBlock> create(u32 index, String name);
~BasicBlock();
u32 index() const { return m_index; }
ReadonlyBytes instruction_stream() const LIFETIME_BOUND { 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 rewind()
{
m_buffer.resize_and_keep_capacity(m_last_instruction_start_offset);
m_terminated = false;
}
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; }
auto const& source_map() const { return m_source_map; }
void add_source_map_entry(u32 bytecode_offset, SourceRecord const& source_record) { m_source_map.append({ bytecode_offset, source_record }); }
[[nodiscard]] bool has_resolved_this() const { return m_has_resolved_this; }
void set_has_resolved_this() { m_has_resolved_this = true; }
[[nodiscard]] size_t last_instruction_start_offset() const { return m_last_instruction_start_offset; }
void set_last_instruction_start_offset(size_t offset) { m_last_instruction_start_offset = offset; }
private:
explicit BasicBlock(u32 index, String name);
u32 m_index { 0 };
Vector<u8> m_buffer;
BasicBlock const* m_handler { nullptr };
BasicBlock const* m_finalizer { nullptr };
String m_name;
bool m_terminated { false };
bool m_has_resolved_this { false };
Vector<SourceMapEntry> m_source_map;
size_t m_last_instruction_start_offset { 0 };
};
}