dmaax/ladybird
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

LibWasm: Avoid unnecessary bounds checks in memory ops

Browse source
This commit is contained in:
Ali Mohammad Pur 2026-01-23 12:44:40 +01:00 committed by Ali Mohammad Pur
parent ae9ced65b7
commit 0e6943b17d
2 changed files with 30 additions and 25 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

54
Libraries/LibWasm/AbstractMachine/BytecodeInterpreter.cpp
View file

@ -1997,7 +1997,7 @@ HANDLE_INSTRUCTION(global_set)
HANDLE_INSTRUCTION(memory_size)
{
LOG_INSN;
auto& args = instruction->arguments().get<Instruction::MemoryIndexArgument>();
auto& args = instruction->arguments().unsafe_get<Instruction::MemoryIndexArgument>();
auto address = configuration.frame().module().memories().data()[args.memory_index.value()];
auto instance = configuration.store().get(address);
auto pages = instance->size() / Constants::page_size;
@ -2009,7 +2009,7 @@ HANDLE_INSTRUCTION(memory_size)
HANDLE_INSTRUCTION(memory_grow)
{
LOG_INSN;
auto& args = instruction->arguments().get<Instruction::MemoryIndexArgument>();
auto& args = instruction->arguments().unsafe_get<Instruction::MemoryIndexArgument>();
auto address = configuration.frame().module().memories().data()[args.memory_index.value()];
auto instance = configuration.store().get(address);
i32 old_pages = instance->size() / Constants::page_size;
@ -2027,7 +2027,7 @@ HANDLE_INSTRUCTION(memory_fill)
{
LOG_INSN;
{
auto& args = instruction->arguments().get<Instruction::MemoryIndexArgument>();
auto& args = instruction->arguments().unsafe_get<Instruction::MemoryIndexArgument>();
auto address = configuration.frame().module().memories().data()[args.memory_index.value()];
auto instance = configuration.store().get(address);
// bounds checked by verifier.
@ -2054,7 +2054,7 @@ HANDLE_INSTRUCTION(memory_fill)
HANDLE_INSTRUCTION(memory_copy)
{
LOG_INSN;
auto& args = instruction->arguments().get<Instruction::MemoryCopyArgs>();
auto& args = instruction->arguments().unsafe_get<Instruction::MemoryCopyArgs>();
auto source_address = configuration.frame().module().memories().data()[args.src_index.value()];
auto destination_address = configuration.frame().module().memories().data()[args.dst_index.value()];
auto source_instance = configuration.store().get(source_address);
@ -2095,7 +2095,7 @@ HANDLE_INSTRUCTION(memory_copy)
HANDLE_INSTRUCTION(memory_init)
{
LOG_INSN;
auto& args = instruction->arguments().get<Instruction::MemoryInitArgs>();
auto& args = instruction->arguments().unsafe_get<Instruction::MemoryInitArgs>();
auto& data_address = configuration.frame().module().datas()[args.data_index.value()];
auto& data = *configuration.store().get(data_address);
auto memory_address = configuration.frame().module().memories().data()[args.memory_index.value()];
@ -4526,31 +4526,35 @@ FLATTEN void BytecodeInterpreter::interpret_impl(Configuration& configuration, E
}
}
template<bool NeedsStackAdjustment>
InstructionPointer BytecodeInterpreter::branch_to_label(Configuration& configuration, LabelIndex index)
{
dbgln_if(WASM_TRACE_DEBUG, "Branch to label with index {}...", index.value());
auto& label_stack = configuration.label_stack();
label_stack.shrink(label_stack.size() - index.value(), true);
auto label = configuration.label_stack().last();
auto const& label = configuration.label_stack().last();
dbgln_if(WASM_TRACE_DEBUG, "...which is actually IP {}, and has {} result(s)", label.continuation().value(), label.arity());
configuration.value_stack().remove(label.stack_height(), configuration.value_stack().size() - label.stack_height() - label.arity());
if constexpr (NeedsStackAdjustment)
configuration.value_stack().remove(label.stack_height(), configuration.value_stack().size() - label.stack_height() - label.arity());
else
VERIFY(configuration.value_stack().size() - label.stack_height() - label.arity() == 0);
return label.continuation().value() - 1;
}
template<typename ReadType, typename PushType>
bool BytecodeInterpreter::load_and_push(Configuration& configuration, Instruction const& instruction, SourcesAndDestination const& addresses)
{
auto& arg = instruction.arguments().get<Instruction::MemoryArgument>();
auto& address = configuration.frame().module().memories()[arg.memory_index.value()];
auto memory = configuration.store().get(address);
auto& arg = instruction.arguments().unsafe_get<Instruction::MemoryArgument>();
auto& address = configuration.frame().module().memories().data()[arg.memory_index.value()];
auto memory = configuration.store().unsafe_get(address);
auto& entry = configuration.source_value<SourceAddressMix::Any>(0, addresses.sources); // bounds checked by verifier.
auto base = entry.template to<i32>();
u64 instance_address = static_cast<u64>(bit_cast<u32>(base)) + arg.offset;
dbgln_if(WASM_TRACE_DEBUG, "load({} : {}) -> stack", instance_address, sizeof(ReadType));
if (instance_address + sizeof(ReadType) > memory->size()) {
m_trap = Trap::from_string("Memory access out of bounds");
dbgln("LibWasm: load_and_push - Memory access out of bounds (expected {} to be less than or equal to {})", instance_address + sizeof(ReadType), memory->size());
dbgln_if(WASM_TRACE_DEBUG, "LibWasm: load_and_push - Memory access out of bounds (expected {} to be less than or equal to {})", instance_address + sizeof(ReadType), memory->size());
return true;
}
auto slice = memory->data().bytes().slice(instance_address, sizeof(ReadType));
@ -4568,9 +4572,9 @@ ALWAYS_INLINE static TDst convert_vector(TSrc v)
template<size_t M, size_t N, template<typename> typename SetSign>
bool BytecodeInterpreter::load_and_push_mxn(Configuration& configuration, Instruction const& instruction, SourcesAndDestination const& addresses)
{
auto& arg = instruction.arguments().get<Instruction::MemoryArgument>();
auto& address = configuration.frame().module().memories()[arg.memory_index.value()];
auto memory = configuration.store().get(address);
auto& arg = instruction.arguments().unsafe_get<Instruction::MemoryArgument>();
auto& address = configuration.frame().module().memories().data()[arg.memory_index.value()];
auto memory = configuration.store().unsafe_get(address);
auto& entry = configuration.source_value<SourceAddressMix::Any>(0, addresses.sources); // bounds checked by verifier.
auto base = entry.template to<i32>();
u64 instance_address = static_cast<u64>(bit_cast<u32>(base)) + arg.offset;
@ -4598,9 +4602,9 @@ bool BytecodeInterpreter::load_and_push_mxn(Configuration& configuration, Instru
template<size_t N>
bool BytecodeInterpreter::load_and_push_lane_n(Configuration& configuration, Instruction const& instruction, SourcesAndDestination const& addresses)
{
auto memarg_and_lane = instruction.arguments().get<Instruction::MemoryAndLaneArgument>();
auto& address = configuration.frame().module().memories()[memarg_and_lane.memory.memory_index.value()];
auto memory = configuration.store().get(address);
auto memarg_and_lane = instruction.arguments().unsafe_get<Instruction::MemoryAndLaneArgument>();
auto& address = configuration.frame().module().memories().data()[memarg_and_lane.memory.memory_index.value()];
auto memory = configuration.store().unsafe_get(address);
// bounds checked by verifier.
auto vector = configuration.take_source<SourceAddressMix::Any>(0, addresses.sources).template to<u128>();
auto base = configuration.take_source<SourceAddressMix::Any>(1, addresses.sources).template to<u32>();
@ -4622,9 +4626,9 @@ bool BytecodeInterpreter::load_and_push_lane_n(Configuration& configuration, Ins
template<size_t N>
bool BytecodeInterpreter::load_and_push_zero_n(Configuration& configuration, Instruction const& instruction, SourcesAndDestination const& addresses)
{
auto memarg_and_lane = instruction.arguments().get<Instruction::MemoryArgument>();
auto& address = configuration.frame().module().memories()[memarg_and_lane.memory_index.value()];
auto memory = configuration.store().get(address);
auto memarg_and_lane = instruction.arguments().unsafe_get<Instruction::MemoryArgument>();
auto& address = configuration.frame().module().memories().data()[memarg_and_lane.memory_index.value()];
auto memory = configuration.store().unsafe_get(address);
// bounds checked by verifier.
auto base = configuration.take_source<SourceAddressMix::Any>(0, addresses.sources).template to<u32>();
u64 instance_address = static_cast<u64>(bit_cast<u32>(base)) + memarg_and_lane.offset;
@ -4645,9 +4649,9 @@ bool BytecodeInterpreter::load_and_push_zero_n(Configuration& configuration, Ins
template<size_t M>
bool BytecodeInterpreter::load_and_push_m_splat(Configuration& configuration, Instruction const& instruction, SourcesAndDestination const& addresses)
{
auto& arg = instruction.arguments().get<Instruction::MemoryArgument>();
auto& address = configuration.frame().module().memories()[arg.memory_index.value()];
auto memory = configuration.store().get(address);
auto& arg = instruction.arguments().unsafe_get<Instruction::MemoryArgument>();
auto& address = configuration.frame().module().memories().data()[arg.memory_index.value()];
auto memory = configuration.store().unsafe_get(address);
auto& entry = configuration.source_value<SourceAddressMix::Any>(0, addresses.sources); // bounds checked by verifier.
auto base = entry.template to<i32>();
u64 instance_address = static_cast<u64>(bit_cast<u32>(base)) + arg.offset;
@ -4858,7 +4862,7 @@ bool BytecodeInterpreter::store_value(Configuration& configuration, Instruction
template<size_t N>
bool BytecodeInterpreter::pop_and_store_lane_n(Configuration& configuration, Instruction const& instruction, SourcesAndDestination const& addresses)
{
auto& memarg_and_lane = instruction.arguments().get<Instruction::MemoryAndLaneArgument>();
auto& memarg_and_lane = instruction.arguments().unsafe_get<Instruction::MemoryAndLaneArgument>();
// bounds checked by verifier.
auto vector = configuration.take_source<SourceAddressMix::Any>(0, addresses.sources).template to<u128>();
auto src = bit_cast<u8*>(&vector) + memarg_and_lane.lane * N / 8;
@ -4869,7 +4873,7 @@ bool BytecodeInterpreter::pop_and_store_lane_n(Configuration& configuration, Ins
bool BytecodeInterpreter::store_to_memory(Configuration& configuration, Instruction::MemoryArgument const& arg, ReadonlyBytes data, u32 base)
{
auto const& address = configuration.frame().module().memories().data()[arg.memory_index.value()];
auto memory = configuration.store().get(address);
auto memory = configuration.store().unsafe_get(address);
u64 instance_address = static_cast<u64>(base) + arg.offset;
return store_to_memory(*memory, instance_address, data);
}

1
Utilities/wasm.cpp
View file

@ -740,6 +740,7 @@ ErrorOr<int> ladybird_main(Main::Arguments arguments)
}
TRY(g_stdout->write_until_depleted(ByteString::formatted("Function #{}{} (stack usage = {}):\n", address.value(), export_name, expression.stack_usage_hint())));
Wasm::Printer printer { *g_stdout, 1 };
for (size_t ip = 0; ip < expression.compiled_instructions.dispatches.size(); ++ip) {
auto& dispatch = expression.compiled_instructions.dispatches[ip];