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LibJS/JIT: Add fast path for cached PutById

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This commit is contained in:
Andreas Kling 2023-11-09 09:28:04 +01:00
parent b1b2ca1485
commit 55e467c359
Notes: sideshowbarker 2024-07-17 11:33:34 +09:00 
Author: https://github.com/awesomekling
Commit: https://github.com/SerenityOS/serenity/commit/55e467c359
Pull-request: https://github.com/SerenityOS/serenity/pull/21859
7 changed files with 189 additions and 12 deletions
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2
AK/Weakable.h
View file

@ -42,6 +42,8 @@ public:
void revoke() { m_ptr = nullptr; }
static FlatPtr ptr_offset() { return OFFSET_OF(WeakLink, m_ptr); }
private:
template<typename T>
explicit WeakLink(T& weakable)

34
Userland/Libraries/LibJIT/X86_64/Assembler.h
View file

@ -619,6 +619,23 @@ struct X86_64Assembler {
}
}
void shift_left(Operand dest, Optional<Operand> count)
{
VERIFY(dest.type == Operand::Type::Reg);
if (count.has_value()) {
VERIFY(count->type == Operand::Type::Imm);
VERIFY(count->fits_in_u8());
emit_rex_for_slash(dest, REX_W::Yes);
emit8(0xc1);
emit_modrm_slash(4, dest);
emit8(count->offset_or_immediate);
} else {
emit_rex_for_slash(dest, REX_W::Yes);
emit8(0xd3);
emit_modrm_slash(4, dest);
}
}
void shift_left32(Operand dest, Optional<Operand> count)
{
VERIFY(dest.type == Operand::Type::Reg);
@ -653,6 +670,23 @@ struct X86_64Assembler {
}
}
void arithmetic_right_shift(Operand dest, Optional<Operand> count)
{
VERIFY(dest.type == Operand::Type::Reg);
if (count.has_value()) {
VERIFY(count->type == Operand::Type::Imm);
VERIFY(count->fits_in_u8());
emit_rex_for_slash(dest, REX_W::Yes);
emit8(0xc1);
emit_modrm_slash(7, dest);
emit8(count->offset_or_immediate);
} else {
emit_rex_for_slash(dest, REX_W::Yes);
emit8(0xd3);
emit_modrm_slash(7, dest);
}
}
void arithmetic_right_shift32(Operand dest, Optional<Operand> count)
{
VERIFY(dest.type == Operand::Type::Reg);

4
Userland/Libraries/LibJS/Bytecode/Executable.h
View file

@ -24,6 +24,10 @@ class NativeExecutable;
namespace JS::Bytecode {
struct PropertyLookupCache {
static FlatPtr shape_offset() { return OFFSET_OF(PropertyLookupCache, shape); }
static FlatPtr property_offset_offset() { return OFFSET_OF(PropertyLookupCache, property_offset); }
static FlatPtr unique_shape_serial_number_offset() { return OFFSET_OF(PropertyLookupCache, unique_shape_serial_number); }
WeakPtr<Shape> shape;
Optional<u32> property_offset;
u64 unique_shape_serial_number { 0 };

132
Userland/Libraries/LibJS/JIT/Compiler.cpp
View file

@ -302,22 +302,22 @@ void Compiler::jump_if_int32(Assembler::Reg reg, Assembler::Label& label)
}
template<typename Codegen>
void Compiler::branch_if_int32(Assembler::Reg reg, Codegen codegen)
void Compiler::branch_if_type(Assembler::Reg reg, u16 type_tag, Codegen codegen)
{
// GPR0 = reg >> 48;
m_assembler.mov(Assembler::Operand::Register(GPR0), Assembler::Operand::Register(reg));
m_assembler.shift_right(Assembler::Operand::Register(GPR0), Assembler::Operand::Imm(48));
Assembler::Label not_int32_case {};
Assembler::Label not_type_case {};
m_assembler.jump_if(
Assembler::Operand::Register(GPR0),
Assembler::Condition::NotEqualTo,
Assembler::Operand::Imm(INT32_TAG),
not_int32_case);
Assembler::Operand::Imm(type_tag),
not_type_case);
codegen();
not_int32_case.link(m_assembler);
not_type_case.link(m_assembler);
}
template<typename Codegen>
@ -1347,9 +1347,125 @@ static Value cxx_put_by_id(VM& vm, Value base, DeprecatedFlyString const& proper
return value;
}
void Compiler::extract_object_pointer(Assembler::Reg dst_object, Assembler::Reg src_value)
{
// This is basically Value::as_object() where src_value is the Value.
m_assembler.mov(
Assembler::Operand::Register(dst_object),
Assembler::Operand::Register(src_value));
m_assembler.shift_left(
Assembler::Operand::Register(dst_object),
Assembler::Operand::Imm(16));
m_assembler.arithmetic_right_shift(
Assembler::Operand::Register(dst_object),
Assembler::Operand::Imm(16));
}
void Compiler::compile_put_by_id(Bytecode::Op::PutById const& op)
{
auto& cache = m_bytecode_executable.property_lookup_caches[op.cache_index()];
load_vm_register(ARG1, op.base());
m_assembler.mov(
Assembler::Operand::Register(ARG5),
Assembler::Operand::Imm(bit_cast<u64>(&cache)));
Assembler::Label end;
Assembler::Label slow_case;
if (op.kind() == Bytecode::Op::PropertyKind::KeyValue) {
branch_if_object(ARG1, [&] {
extract_object_pointer(GPR0, ARG1);
// if (cache.shape != &object->shape()) goto slow_case;
m_assembler.mov(
Assembler::Operand::Register(GPR2),
Assembler::Operand::Mem64BaseAndOffset(GPR0, Object::shape_offset()));
m_assembler.mov(
Assembler::Operand::Register(GPR1),
Assembler::Operand::Mem64BaseAndOffset(ARG5, Bytecode::PropertyLookupCache::shape_offset()));
m_assembler.jump_if(
Assembler::Operand::Register(GPR1),
Assembler::Condition::EqualTo,
Assembler::Operand::Imm(0),
slow_case);
m_assembler.mov(
Assembler::Operand::Register(GPR1),
Assembler::Operand::Mem64BaseAndOffset(GPR1, AK::WeakLink::ptr_offset()));
m_assembler.jump_if(
Assembler::Operand::Register(GPR2),
Assembler::Condition::NotEqualTo,
Assembler::Operand::Register(GPR1),
slow_case);
// (!object->shape().is_unique() || object->shape().unique_shape_serial_number() == cache.unique_shape_serial_number)) {
Assembler::Label fast_case;
// GPR1 = object->shape().is_unique()
m_assembler.mov8(
Assembler::Operand::Register(GPR1),
Assembler::Operand::Mem64BaseAndOffset(GPR2, Shape::is_unique_offset()));
m_assembler.jump_if(
Assembler::Operand::Register(GPR1),
Assembler::Condition::EqualTo,
Assembler::Operand::Imm(0),
fast_case);
// GPR1 = object->shape().unique_shape_serial_number()
m_assembler.mov(
Assembler::Operand::Register(GPR1),
Assembler::Operand::Mem64BaseAndOffset(GPR2, Shape::unique_shape_serial_number_offset()));
// GPR2 = cache.unique_shape_serial_number
m_assembler.mov(
Assembler::Operand::Register(GPR2),
Assembler::Operand::Mem64BaseAndOffset(ARG5, Bytecode::PropertyLookupCache::unique_shape_serial_number_offset()));
// if (GPR1 != GPR2) goto slow_case;
m_assembler.jump_if(
Assembler::Operand::Register(GPR1),
Assembler::Condition::NotEqualTo,
Assembler::Operand::Register(GPR2),
slow_case);
fast_case.link(m_assembler);
// object->put_direct(*cache.property_offset, value);
// GPR0 = object
// GPR1 = *cache.property_offset * sizeof(Value)
m_assembler.mov(
Assembler::Operand::Register(GPR1),
Assembler::Operand::Mem64BaseAndOffset(ARG5, Bytecode::PropertyLookupCache::property_offset_offset() + decltype(cache.property_offset)::value_offset()));
m_assembler.mul32(
Assembler::Operand::Register(GPR1),
Assembler::Operand::Imm(sizeof(Value)),
slow_case);
// GPR0 = object->m_storage.outline_buffer
m_assembler.mov(
Assembler::Operand::Register(GPR0),
Assembler::Operand::Mem64BaseAndOffset(GPR0, Object::storage_offset() + Vector<Value>::outline_buffer_offset()));
// GPR0 = &object->m_storage.outline_buffer[*cache.property_offset]
m_assembler.add(
Assembler::Operand::Register(GPR0),
Assembler::Operand::Register(GPR1));
// *GPR0 = value
load_accumulator(GPR1);
m_assembler.mov(
Assembler::Operand::Mem64BaseAndOffset(GPR0, 0),
Assembler::Operand::Register(GPR1));
m_assembler.jump(end);
});
}
slow_case.link(m_assembler);
m_assembler.mov(
Assembler::Operand::Register(ARG2),
Assembler::Operand::Imm(bit_cast<u64>(&m_bytecode_executable.get_identifier(op.property()))));
@ -1357,12 +1473,12 @@ void Compiler::compile_put_by_id(Bytecode::Op::PutById const& op)
m_assembler.mov(
Assembler::Operand::Register(ARG4),
Assembler::Operand::Imm(to_underlying(op.kind())));
m_assembler.mov(
Assembler::Operand::Register(ARG5),
Assembler::Operand::Imm(bit_cast<u64>(&m_bytecode_executable.property_lookup_caches[op.cache_index()])));
native_call((void*)cxx_put_by_id);
store_accumulator(RET);
check_exception();
end.link(m_assembler);
}
static Value cxx_put_by_value(VM& vm, Value base, Value property, Value value, Bytecode::Op::PropertyKind kind)

20
Userland/Libraries/LibJS/JIT/Compiler.h
View file

@ -27,7 +27,7 @@ private:
# if ARCH(X86_64)
static constexpr auto GPR0 = Assembler::Reg::RAX;
static constexpr auto GPR1 = Assembler::Reg::RCX;
static constexpr auto GPR2 = Assembler::Reg::R12;
static constexpr auto GPR2 = Assembler::Reg::R13;
static constexpr auto ARG0 = Assembler::Reg::RDI;
static constexpr auto ARG1 = Assembler::Reg::RSI;
static constexpr auto ARG2 = Assembler::Reg::RDX;
@ -38,7 +38,7 @@ private:
static constexpr auto STACK_POINTER = Assembler::Reg::RSP;
static constexpr auto REGISTER_ARRAY_BASE = Assembler::Reg::RBX;
static constexpr auto LOCALS_ARRAY_BASE = Assembler::Reg::R14;
static constexpr auto CACHED_ACCUMULATOR = Assembler::Reg::R13;
static constexpr auto CACHED_ACCUMULATOR = Assembler::Reg::R12;
static constexpr auto RUNNING_EXECUTION_CONTEXT_BASE = Assembler::Reg::R15;
# endif
@ -171,7 +171,21 @@ private:
void jump_if_int32(Assembler::Reg, Assembler::Label&);
template<typename Codegen>
void branch_if_int32(Assembler::Reg, Codegen);
void branch_if_type(Assembler::Reg, u16 type_tag, Codegen);
template<typename Codegen>
void branch_if_int32(Assembler::Reg reg, Codegen codegen)
{
branch_if_type(reg, INT32_TAG, codegen);
}
template<typename Codegen>
void branch_if_object(Assembler::Reg reg, Codegen codegen)
{
branch_if_type(reg, OBJECT_TAG, codegen);
}
void extract_object_pointer(Assembler::Reg dst_object, Assembler::Reg src_value);
template<typename Codegen>
void branch_if_both_int32(Assembler::Reg, Assembler::Reg, Codegen);

4
Userland/Libraries/LibJS/Runtime/Object.h
View file

@ -195,6 +195,8 @@ public:
Value get_direct(size_t index) const { return m_storage[index]; }
void put_direct(size_t index, Value value) { m_storage[index] = value; }
static FlatPtr storage_offset() { return OFFSET_OF(Object, m_storage); }
IndexedProperties const& indexed_properties() const { return m_indexed_properties; }
IndexedProperties& indexed_properties() { return m_indexed_properties; }
void set_indexed_property_elements(Vector<Value>&& values) { m_indexed_properties = IndexedProperties(move(values)); }
@ -202,6 +204,8 @@ public:
Shape& shape() { return *m_shape; }
Shape const& shape() const { return *m_shape; }
static FlatPtr shape_offset() { return OFFSET_OF(Object, m_shape); }
void ensure_shape_is_unique();
template<typename T>

5
Userland/Libraries/LibJS/Runtime/Shape.h
View file

@ -57,6 +57,8 @@ public:
void add_property_without_transition(PropertyKey const&, PropertyAttributes);
bool is_unique() const { return m_unique; }
static FlatPtr is_unique_offset() { return OFFSET_OF(Shape, m_unique); }
Shape* create_unique_clone() const;
Realm& realm() const { return m_realm; }
@ -80,6 +82,7 @@ public:
void reconfigure_property_in_unique_shape(StringOrSymbol const& property_key, PropertyAttributes attributes);
[[nodiscard]] u64 unique_shape_serial_number() const { return m_unique_shape_serial_number; }
static FlatPtr unique_shape_serial_number_offset() { return OFFSET_OF(Shape, m_unique_shape_serial_number); }
private:
explicit Shape(Realm&);
@ -106,7 +109,7 @@ private:
PropertyAttributes m_attributes { 0 };
TransitionType m_transition_type : 6 { TransitionType::Invalid };
bool m_unique : 1 { false };
bool m_unique { false };
// Since unique shapes never change identity, inline caches use this incrementing serial number
// to know whether its property table has been modified since last time we checked.