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LibJS/JIT: Add fastpath for set variable

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This commit is contained in:
Stephan Vedder 2023-11-16 07:13:35 +01:00 • committed by Andreas Kling
parent b3cbe0fdb9
commit 84eecbb10e
8 changed files with 148 additions and 12 deletions
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128
Userland/Libraries/LibJS/JIT/Compiler.cpp
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@ -2736,18 +2736,140 @@ static Value cxx_set_variable(
DeprecatedFlyString const& identifier,
Value value,
Bytecode::Op::EnvironmentMode environment_mode,
Bytecode::Op::SetVariable::InitializationMode initialization_mode)
Bytecode::Op::SetVariable::InitializationMode initialization_mode,
Bytecode::EnvironmentVariableCache& cache)
{
TRY_OR_SET_EXCEPTION(Bytecode::set_variable(vm, identifier, value, environment_mode, initialization_mode));
TRY_OR_SET_EXCEPTION(Bytecode::set_variable(vm, identifier, value, environment_mode, initialization_mode, cache));
return {};
}
void Compiler::compile_set_variable(Bytecode::Op::SetVariable const& op)
{
Assembler::Label slow_case;
// Load the identifier in ARG1 for both cases
m_assembler.mov(
Assembler::Operand::Register(ARG1),
Assembler::Operand::Imm(bit_cast<u64>(&m_bytecode_executable.get_identifier(op.identifier().value()))));
// Load the value in ARG2 for both cases
load_accumulator(ARG2);
// if (!cache.has_value()) goto slow_case;
m_assembler.mov(
Assembler::Operand::Register(ARG5),
Assembler::Operand::Imm(bit_cast<u64>(&m_bytecode_executable.environment_variable_caches[op.cache_index()])));
m_assembler.mov8(
Assembler::Operand::Register(GPR0),
Assembler::Operand::Mem64BaseAndOffset(ARG5, Bytecode::EnvironmentVariableCache::has_value_offset()));
m_assembler.jump_if(
Assembler::Operand::Register(GPR0),
Assembler::Condition::EqualTo,
Assembler::Operand::Imm(0),
slow_case);
if (op.mode() == Bytecode::Op::EnvironmentMode::Lexical) {
// auto environment = vm.running_execution_context().lexical_environment;
// GPR1 = current lexical environment
m_assembler.mov(
Assembler::Operand::Register(GPR1),
Assembler::Operand::Mem64BaseAndOffset(RUNNING_EXECUTION_CONTEXT_BASE, ExecutionContext::lexical_environment_offset()));
} else {
// auto environment = vm.running_execution_context().variable_environment;
// GPR1 = current variable environment
m_assembler.mov(
Assembler::Operand::Register(GPR1),
Assembler::Operand::Mem64BaseAndOffset(RUNNING_EXECUTION_CONTEXT_BASE, ExecutionContext::variable_environment_offset()));
}
// for (size_t i = 0; i < cache->hops; ++i)
// environment = environment->outer_environment();
// GPR0 = hops
m_assembler.mov32(
Assembler::Operand::Register(GPR0),
Assembler::Operand::Mem64BaseAndOffset(ARG5, Bytecode::EnvironmentVariableCache::value_offset() + EnvironmentCoordinate::hops_offset()));
{
// while (GPR0--)
// GPR1 = GPR1->outer_environment()
Assembler::Label loop_start;
Assembler::Label loop_end;
loop_start.link(m_assembler);
m_assembler.jump_if(
Assembler::Operand::Register(GPR0),
Assembler::Condition::EqualTo,
Assembler::Operand::Imm(0),
loop_end);
m_assembler.sub(
Assembler::Operand::Register(GPR0),
Assembler::Operand::Imm(1));
m_assembler.mov(
Assembler::Operand::Register(GPR1),
Assembler::Operand::Mem64BaseAndOffset(GPR1, Environment::outer_environment_offset()));
m_assembler.jump(loop_start);
loop_end.link(m_assembler);
}
// GPR1 now points to the environment holding our binding.
// if (environment->is_permanently_screwed_by_eval()) goto slow_case;
m_assembler.mov8(
Assembler::Operand::Register(GPR0),
Assembler::Operand::Mem64BaseAndOffset(GPR1, Environment::is_permanently_screwed_by_eval_offset()));
m_assembler.jump_if(
Assembler::Operand::Register(GPR0),
Assembler::Condition::NotEqualTo,
Assembler::Operand::Imm(0),
slow_case);
// GPR1 = environment->m_bindings.outline_buffer()
m_assembler.mov(
Assembler::Operand::Register(GPR1),
Assembler::Operand::Mem64BaseAndOffset(GPR1, DeclarativeEnvironment::bindings_offset() + Vector<DeclarativeEnvironment::Binding>::outline_buffer_offset()));
// GPR0 = index
m_assembler.mov32(
Assembler::Operand::Register(GPR0),
Assembler::Operand::Mem64BaseAndOffset(ARG5, Bytecode::EnvironmentVariableCache::value_offset() + EnvironmentCoordinate::index_offset()));
// GPR0 *= sizeof(DeclarativeEnvironment::Binding)
m_assembler.mul32(
Assembler::Operand::Register(GPR0),
Assembler::Operand::Imm(sizeof(DeclarativeEnvironment::Binding)),
slow_case);
// GPR1 = &binding
m_assembler.add(
Assembler::Operand::Register(GPR1),
Assembler::Operand::Register(GPR0));
// if (!binding.initialized) goto slow_case;
m_assembler.mov(
Assembler ::Operand::Register(GPR0),
Assembler::Operand::Mem64BaseAndOffset(GPR1, DeclarativeEnvironment::Binding::initialized_offset()));
m_assembler.bitwise_and(
Assembler::Operand::Register(GPR0),
Assembler::Operand::Imm(0xff));
m_assembler.jump_if(
Assembler::Operand::Register(GPR0),
Assembler::Condition::EqualTo,
Assembler::Operand::Imm(0),
slow_case);
// binding.value = accumulator;
m_assembler.mov(
Assembler::Operand::Mem64BaseAndOffset(GPR1, DeclarativeEnvironment::Binding::value_offset()),
Assembler::Operand::Register(ARG2));
Assembler::Label end;
m_assembler.jump(end);
// Slow case: Uncached access. Call C++ helper.
slow_case.link(m_assembler);
m_assembler.mov(
Assembler::Operand::Register(ARG3),
Assembler::Operand::Imm(to_underlying(op.mode())));
@ -2756,6 +2878,8 @@ void Compiler::compile_set_variable(Bytecode::Op::SetVariable const& op)
Assembler::Operand::Imm(to_underlying(op.initialization_mode())));
native_call((void*)cxx_set_variable);
check_exception();
end.link(m_assembler);
}
void Compiler::compile_continue_pending_unwind(Bytecode::Op::ContinuePendingUnwind const& op)