ladybird/Userland/Libraries/LibWasm/AbstractMachine/Configuration.cpp
Ali Mohammad Pur 056be42c0b LibWasm: Start implementing a naive bytecode interpreter
As the parser now flattens out the instructions and inserts synthetic
nesting/structured instructions where needed, we can treat the whole
thing as a simple parsed bytecode stream.
This currently knows how to execute the following instructions:
- unreachable
- nop
- local.get
- local.set
- {i,f}{32,64}.const
- block
- loop
- if/else
- branch / branch_if
- i32_add
- i32_and/or/xor
- i32_ne

This also extends the 'wasm' utility to optionally execute the first
function in the module with optionally user-supplied arguments.
2021-05-17 23:25:30 +02:00

106 lines
3.4 KiB
C++

/*
* Copyright (c) 2021, Ali Mohammad Pur <mpfard@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibWasm/AbstractMachine/Configuration.h>
#include <LibWasm/AbstractMachine/Interpreter.h>
namespace Wasm {
Optional<Label> Configuration::nth_label(size_t i)
{
for (auto& entry : m_stack.entries()) {
if (auto ptr = entry.get_pointer<NonnullOwnPtr<Label>>()) {
if (i == 0)
return **ptr;
--i;
}
}
return {};
}
Result Configuration::call(FunctionAddress address, Vector<Value> arguments)
{
auto* function = m_store.get(address);
if (!function)
return Trap {};
if (auto* wasm_function = function->get_pointer<WasmFunction>()) {
Vector<Value> locals;
locals.ensure_capacity(arguments.size() + wasm_function->code().locals().size());
for (auto& value : arguments)
locals.append(Value { value });
for (auto& type : wasm_function->code().locals())
locals.empend(type, 0ull);
auto frame = make<Frame>(
wasm_function->module(),
move(locals),
wasm_function->code().body(),
wasm_function->type().results().size());
set_frame(move(frame));
return execute();
}
// It better be a host function, else something is really wrong.
auto& host_function = function->get<HostFunction>();
auto result = bit_cast<HostFunctionType>(host_function.ptr())(m_store, arguments);
auto count = host_function.type().results().size();
if (count == 0)
return Result { Vector<Value> {} };
if (count == 1)
return Result { Vector<Value> { Value { host_function.type().results().first(), result } } };
TODO();
}
Result Configuration::execute()
{
Interpreter interpreter;
interpreter.interpret(*this);
Vector<NonnullOwnPtr<Value>> results;
for (size_t i = 0; i < m_current_frame->arity(); ++i)
results.append(move(stack().pop().get<NonnullOwnPtr<Value>>()));
auto label = stack().pop();
// ASSERT: label == current frame
if (!label.has<NonnullOwnPtr<Label>>())
return Trap {};
Vector<Value> results_moved;
results_moved.ensure_capacity(results.size());
for (auto& entry : results)
results_moved.unchecked_append(move(*entry));
return Result { move(results_moved) };
}
void Configuration::dump_stack()
{
for (const auto& entry : stack().entries()) {
entry.visit(
[](const NonnullOwnPtr<Value>& v) {
v->value().visit([]<typename T>(const T& v) {
if constexpr (IsIntegral<T> || IsFloatingPoint<T>)
dbgln(" {}", v);
else
dbgln(" *{}", v.value());
});
},
[](const NonnullOwnPtr<Frame>& f) {
dbgln(" frame({})", f->arity());
for (auto& local : f->locals()) {
local.value().visit([]<typename T>(const T& v) {
if constexpr (IsIntegral<T> || IsFloatingPoint<T>)
dbgln(" {}", v);
else
dbgln(" *{}", v.value());
});
}
},
[](const NonnullOwnPtr<Label>& l) {
dbgln(" label({}) -> {}", l->arity(), l->continuation());
});
}
}
}