ladybird/Userland/Libraries/LibWasm/AbstractMachine/AbstractMachine.cpp
Ali Mohammad Pur be62e4d1d7 LibWasm: Load and instantiate tables
This commit is a fairly large refactor, mainly because it unified the
two different ways that existed to represent references.
Now Reference values are also a kind of value.
It also implements a printer for values/references instead of copying
the implementation everywhere.
2021-06-04 16:07:42 +04:30

516 lines
20 KiB
C++

/*
* Copyright (c) 2021, Ali Mohammad Pur <mpfard@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include "Interpreter.h"
#include <LibWasm/AbstractMachine/AbstractMachine.h>
#include <LibWasm/AbstractMachine/Configuration.h>
#include <LibWasm/Types.h>
namespace Wasm {
Optional<FunctionAddress> Store::allocate(ModuleInstance& module, const Module::Function& function)
{
FunctionAddress address { m_functions.size() };
if (function.type().value() > module.types().size())
return {};
auto& type = module.types()[function.type().value()];
m_functions.empend(WasmFunction { type, module, function });
return address;
}
Optional<FunctionAddress> Store::allocate(HostFunction&& function)
{
FunctionAddress address { m_functions.size() };
m_functions.empend(HostFunction { move(function) });
return address;
}
Optional<TableAddress> Store::allocate(const TableType& type)
{
TableAddress address { m_tables.size() };
Vector<Optional<Reference>> elements;
elements.resize(type.limits().min());
m_tables.empend(TableInstance { type, move(elements) });
return address;
}
Optional<MemoryAddress> Store::allocate(const MemoryType& type)
{
MemoryAddress address { m_memories.size() };
m_memories.empend(MemoryInstance { type });
return address;
}
Optional<GlobalAddress> Store::allocate(const GlobalType& type, Value value)
{
GlobalAddress address { m_globals.size() };
m_globals.append(GlobalInstance { move(value), type.is_mutable() });
return address;
}
Optional<ElementAddress> Store::allocate(const ValueType& type, Vector<Reference> references)
{
ElementAddress address { m_elements.size() };
m_elements.append(ElementInstance { type, move(references) });
return address;
}
FunctionInstance* Store::get(FunctionAddress address)
{
auto value = address.value();
if (m_functions.size() <= value)
return nullptr;
return &m_functions[value];
}
TableInstance* Store::get(TableAddress address)
{
auto value = address.value();
if (m_tables.size() <= value)
return nullptr;
return &m_tables[value];
}
MemoryInstance* Store::get(MemoryAddress address)
{
auto value = address.value();
if (m_memories.size() <= value)
return nullptr;
return &m_memories[value];
}
GlobalInstance* Store::get(GlobalAddress address)
{
auto value = address.value();
if (m_globals.size() <= value)
return nullptr;
return &m_globals[value];
}
ElementInstance* Store::get(ElementAddress address)
{
auto value = address.value();
if (m_elements.size() <= value)
return nullptr;
return &m_elements[value];
}
InstantiationResult AbstractMachine::instantiate(const Module& module, Vector<ExternValue> externs)
{
auto main_module_instance_pointer = make<ModuleInstance>();
auto& main_module_instance = *main_module_instance_pointer;
Optional<InstantiationResult> instantiation_result;
module.for_each_section_of_type<TypeSection>([&](const TypeSection& section) {
main_module_instance.types() = section.types();
});
// FIXME: Validate stuff
Vector<Value> global_values;
Vector<Vector<Reference>> elements;
ModuleInstance auxiliary_instance;
// FIXME: Check that imports/extern match
for (auto& entry : externs) {
if (auto* ptr = entry.get_pointer<GlobalAddress>())
auxiliary_instance.globals().append(*ptr);
}
BytecodeInterpreter interpreter;
module.for_each_section_of_type<GlobalSection>([&](auto& global_section) {
for (auto& entry : global_section.entries()) {
Configuration config { m_store };
config.set_frame(Frame {
auxiliary_instance,
Vector<Value> {},
entry.expression(),
1,
});
auto result = config.execute(interpreter);
if (result.is_trap())
instantiation_result = InstantiationError { "Global value construction trapped" };
else
global_values.append(result.values().first());
}
});
if (instantiation_result.has_value())
return instantiation_result.release_value();
if (auto result = allocate_all_initial_phase(module, main_module_instance, externs, global_values); result.has_value())
return result.release_value();
module.for_each_section_of_type<ElementSection>([&](const ElementSection& section) {
for (auto& segment : section.segments()) {
Vector<Reference> references;
for (auto& entry : segment.init) {
Configuration config { m_store };
config.set_frame(Frame {
main_module_instance,
Vector<Value> {},
entry,
entry.instructions().size(),
});
auto result = config.execute(interpreter);
if (result.is_trap()) {
instantiation_result = InstantiationError { "Element construction trapped" };
return IterationDecision::Continue;
}
for (auto& value : result.values()) {
if (!value.type().is_reference()) {
instantiation_result = InstantiationError { "Evaluated element entry is not a reference" };
return IterationDecision::Continue;
}
auto reference = value.to<Reference>();
if (!reference.has_value()) {
instantiation_result = InstantiationError { "Evaluated element entry does not contain a reference" };
return IterationDecision::Continue;
}
// FIXME: type-check the reference.
references.prepend(reference.release_value());
}
}
elements.append(move(references));
}
return IterationDecision::Continue;
});
if (instantiation_result.has_value())
return instantiation_result.release_value();
if (auto result = allocate_all_final_phase(module, main_module_instance, elements); result.has_value())
return result.release_value();
module.for_each_section_of_type<ElementSection>([&](const ElementSection& section) {
size_t index = 0;
for (auto& segment : section.segments()) {
auto current_index = index;
++index;
auto active_ptr = segment.mode.get_pointer<ElementSection::Active>();
if (!active_ptr)
continue;
if (active_ptr->index.value() != 0) {
instantiation_result = InstantiationError { "Non-zero table referenced by active element segment" };
return IterationDecision::Break;
}
Configuration config { m_store };
config.set_frame(Frame {
main_module_instance,
Vector<Value> {},
active_ptr->expression,
1,
});
auto result = config.execute(interpreter);
if (result.is_trap()) {
instantiation_result = InstantiationError { "Element section initialisation trapped" };
return IterationDecision::Break;
}
auto d = result.values().first().to<i32>();
if (!d.has_value()) {
instantiation_result = InstantiationError { "Element section initialisation returned invalid table initial offset" };
return IterationDecision::Break;
}
if (main_module_instance.tables().size() < 1) {
instantiation_result = InstantiationError { "Element section initialisation references nonexistent table" };
return IterationDecision::Break;
}
auto table_instance = m_store.get(main_module_instance.tables()[0]);
if (current_index >= main_module_instance.elements().size()) {
instantiation_result = InstantiationError { "Invalid element referenced by active element segment" };
return IterationDecision::Break;
}
auto elem_instance = m_store.get(main_module_instance.elements()[current_index]);
if (!table_instance || !elem_instance) {
instantiation_result = InstantiationError { "Invalid element referenced by active element segment" };
return IterationDecision::Break;
}
auto total_required_size = elem_instance->references().size() + d.value();
if (table_instance->type().limits().max().value_or(total_required_size) < total_required_size) {
instantiation_result = InstantiationError { "Table limit overflow in active element segment" };
return IterationDecision::Break;
}
if (table_instance->elements().size() < total_required_size)
table_instance->elements().resize(total_required_size);
size_t i = 0;
for (auto it = elem_instance->references().begin(); it < elem_instance->references().end(); ++i, ++it) {
table_instance->elements()[i + d.value()] = *it;
}
}
return IterationDecision::Continue;
});
if (instantiation_result.has_value())
return instantiation_result.release_value();
module.for_each_section_of_type<DataSection>([&](const DataSection& data_section) {
for (auto& segment : data_section.data()) {
segment.value().visit(
[&](const DataSection::Data::Active& data) {
Configuration config { m_store };
config.set_frame(Frame {
main_module_instance,
Vector<Value> {},
data.offset,
1,
});
auto result = config.execute(interpreter);
if (result.is_trap()) {
instantiation_result = InstantiationError { "Data section initialisation trapped" };
return;
}
size_t offset = 0;
result.values().first().value().visit(
[&](const auto& value) { offset = value; },
[&](const Reference&) { instantiation_result = InstantiationError { "Data segment offset returned a reference" }; });
if (instantiation_result.has_value() && instantiation_result->is_error())
return;
if (main_module_instance.memories().size() <= data.index.value()) {
instantiation_result = InstantiationError { String::formatted("Data segment referenced out-of-bounds memory ({}) of max {} entries", data.index.value(), main_module_instance.memories().size()) };
return;
}
auto address = main_module_instance.memories()[data.index.value()];
if (auto instance = m_store.get(address)) {
if (instance->type().limits().max().value_or(data.init.size() + offset + 1) <= data.init.size() + offset) {
instantiation_result = InstantiationError { String::formatted("Data segment attempted to write to out-of-bounds memory ({}) of max {} bytes", data.init.size() + offset, instance->type().limits().max().value()) };
return;
}
if (instance->size() < data.init.size() + offset)
instance->grow(data.init.size() + offset - instance->size());
instance->data().overwrite(offset, data.init.data(), data.init.size());
}
},
[&](const DataSection::Data::Passive&) {
// FIXME: What do we do here?
});
}
});
module.for_each_section_of_type<StartSection>([&](const StartSection& section) {
auto& functions = main_module_instance.functions();
auto index = section.function().index();
if (functions.size() <= index.value()) {
instantiation_result = InstantiationError { String::formatted("Start section function referenced invalid index {} of max {} entries", index.value(), functions.size()) };
return;
}
invoke(functions[index.value()], {});
});
if (instantiation_result.has_value())
return instantiation_result.release_value();
return InstantiationResult { move(main_module_instance_pointer) };
}
Optional<InstantiationError> AbstractMachine::allocate_all_initial_phase(const Module& module, ModuleInstance& module_instance, Vector<ExternValue>& externs, Vector<Value>& global_values)
{
Optional<InstantiationError> result;
for (auto& entry : externs) {
entry.visit(
[&](const FunctionAddress& address) { module_instance.functions().append(address); },
[&](const TableAddress& address) { module_instance.tables().append(address); },
[&](const MemoryAddress& address) { module_instance.memories().append(address); },
[&](const GlobalAddress& address) { module_instance.globals().append(address); });
}
// FIXME: What if this fails?
for (auto& func : module.functions()) {
auto address = m_store.allocate(module_instance, func);
VERIFY(address.has_value());
module_instance.functions().append(*address);
}
module.for_each_section_of_type<TableSection>([&](const TableSection& section) {
for (auto& table : section.tables()) {
auto table_address = m_store.allocate(table.type());
VERIFY(table_address.has_value());
module_instance.tables().append(*table_address);
}
});
module.for_each_section_of_type<MemorySection>([&](const MemorySection& section) {
for (auto& memory : section.memories()) {
auto memory_address = m_store.allocate(memory.type());
VERIFY(memory_address.has_value());
module_instance.memories().append(*memory_address);
}
});
module.for_each_section_of_type<GlobalSection>([&](const GlobalSection& section) {
size_t index = 0;
for (auto& entry : section.entries()) {
auto address = m_store.allocate(entry.type(), move(global_values[index]));
VERIFY(address.has_value());
module_instance.globals().append(*address);
index++;
}
});
module.for_each_section_of_type<ExportSection>([&](const ExportSection& section) {
for (auto& entry : section.entries()) {
Variant<FunctionAddress, TableAddress, MemoryAddress, GlobalAddress, Empty> address { Empty {} };
entry.description().visit(
[&](const FunctionIndex& index) {
if (module_instance.functions().size() > index.value())
address = FunctionAddress { module_instance.functions()[index.value()] };
else
dbgln("Failed to export '{}', the exported address ({}) was out of bounds (min: 0, max: {})", entry.name(), index.value(), module_instance.functions().size());
},
[&](const TableIndex& index) {
if (module_instance.tables().size() > index.value())
address = TableAddress { module_instance.tables()[index.value()] };
else
dbgln("Failed to export '{}', the exported address ({}) was out of bounds (min: 0, max: {})", entry.name(), index.value(), module_instance.tables().size());
},
[&](const MemoryIndex& index) {
if (module_instance.memories().size() > index.value())
address = MemoryAddress { module_instance.memories()[index.value()] };
else
dbgln("Failed to export '{}', the exported address ({}) was out of bounds (min: 0, max: {})", entry.name(), index.value(), module_instance.memories().size());
},
[&](const GlobalIndex& index) {
if (module_instance.globals().size() > index.value())
address = GlobalAddress { module_instance.globals()[index.value()] };
else
dbgln("Failed to export '{}', the exported address ({}) was out of bounds (min: 0, max: {})", entry.name(), index.value(), module_instance.globals().size());
});
if (address.has<Empty>()) {
result = InstantiationError { "An export could not be resolved" };
continue;
}
module_instance.exports().append(ExportInstance {
entry.name(),
move(address).downcast<FunctionAddress, TableAddress, MemoryAddress, GlobalAddress>(),
});
}
});
return result;
}
Optional<InstantiationError> AbstractMachine::allocate_all_final_phase(const Module& module, ModuleInstance& module_instance, Vector<Vector<Reference>>& elements)
{
module.for_each_section_of_type<ElementSection>([&](const ElementSection& section) {
size_t index = 0;
for (auto& segment : section.segments()) {
auto address = m_store.allocate(segment.type, move(elements[index]));
VERIFY(address.has_value());
module_instance.elements().append(*address);
index++;
}
});
return {};
}
Result AbstractMachine::invoke(FunctionAddress address, Vector<Value> arguments)
{
BytecodeInterpreter interpreter;
return invoke(interpreter, address, move(arguments));
}
Result AbstractMachine::invoke(Interpreter& interpreter, FunctionAddress address, Vector<Value> arguments)
{
Configuration configuration { m_store };
return configuration.call(interpreter, address, move(arguments));
}
void Linker::link(const ModuleInstance& instance)
{
populate();
if (m_unresolved_imports.is_empty())
return;
HashTable<Name> resolved_imports;
for (auto& import_ : m_unresolved_imports) {
auto it = instance.exports().find_if([&](auto& export_) { return export_.name() == import_.name; });
if (!it.is_end()) {
resolved_imports.set(import_);
m_resolved_imports.set(import_, it->value());
}
}
for (auto& entry : resolved_imports)
m_unresolved_imports.remove(entry);
}
void Linker::link(const HashMap<Linker::Name, ExternValue>& exports)
{
populate();
if (m_unresolved_imports.is_empty())
return;
HashTable<Name> resolved_imports;
for (auto& import_ : m_unresolved_imports) {
auto export_ = exports.get(import_);
if (export_.has_value()) {
resolved_imports.set(import_);
m_resolved_imports.set(import_, export_.value());
}
}
for (auto& entry : resolved_imports)
m_unresolved_imports.remove(entry);
}
AK::Result<Vector<ExternValue>, LinkError> Linker::finish()
{
populate();
if (!m_unresolved_imports.is_empty()) {
if (!m_error.has_value())
m_error = LinkError {};
for (auto& entry : m_unresolved_imports)
m_error->missing_imports.append(entry.name);
return *m_error;
}
if (m_error.has_value())
return *m_error;
// Result must be in the same order as the module imports
Vector<ExternValue> exports;
exports.ensure_capacity(m_ordered_imports.size());
for (auto& import_ : m_ordered_imports)
exports.unchecked_append(*m_resolved_imports.get(import_));
return exports;
}
void Linker::populate()
{
if (!m_ordered_imports.is_empty())
return;
// There better be at most one import section!
bool already_seen_an_import_section = false;
m_module.for_each_section_of_type<ImportSection>([&](const ImportSection& section) {
if (already_seen_an_import_section) {
if (!m_error.has_value())
m_error = LinkError {};
m_error->other_errors.append(LinkError::InvalidImportedModule);
return;
}
already_seen_an_import_section = true;
for (auto& import_ : section.imports()) {
m_ordered_imports.append({ import_.module(), import_.name(), import_.description() });
m_unresolved_imports.set(m_ordered_imports.last());
}
});
}
}