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LibJS: Devirtualize and pack the bytecode stream :^)

This patch changes the LibJS bytecode to be a stream of instructions
packed one-after-the-other in contiguous memory, instead of a vector
of OwnPtr<Instruction>. This should be a lot more cache-friendly. :^)

Instructions are also devirtualized and instead have a type field
using a new Instruction::Type enum.

To iterate over a bytecode stream, one must now use
Bytecode::InstructionStreamIterator.
This commit is contained in:
Andreas Kling 2021-06-07 15:12:43 +02:00
parent 845f2826aa
commit e7d69c5d3c
11 changed files with 284 additions and 110 deletions

View file

@ -8,6 +8,7 @@
#include <AK/OwnPtr.h>
#include <LibJS/Bytecode/Label.h>
#include <LibJS/Bytecode/Register.h>
#include <LibJS/Forward.h>
namespace JS::Bytecode {
@ -21,10 +22,19 @@ public:
template<typename OpType, typename... Args>
OpType& emit(Args&&... args)
{
auto instruction = make<OpType>(forward<Args>(args)...);
auto* ptr = instruction.ptr();
append(move(instruction));
return *ptr;
void* slot = next_slot();
grow(sizeof(OpType));
new (slot) OpType(forward<Args>(args)...);
return *static_cast<OpType*>(slot);
}
template<typename OpType, typename... Args>
OpType& emit_with_extra_register_slots(size_t extra_register_slots, Args&&... args)
{
void* slot = next_slot();
grow(sizeof(OpType) + extra_register_slots * sizeof(Register));
new (slot) OpType(forward<Args>(args)...);
return *static_cast<OpType*>(slot);
}
Label make_label() const;
@ -38,7 +48,8 @@ private:
Generator();
~Generator();
void append(NonnullOwnPtr<Instruction>);
void grow(size_t);
void* next_slot();
OwnPtr<Block> m_block;
u32 m_next_register { 1 };