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LibWasm: Start implementing a naive bytecode interpreter

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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.
This commit is contained in:
Ali Mohammad Pur 2021-05-01 03:19:01 +04:30 • committed by Andreas Kling
parent faa34a0a8b
commit 056be42c0b
10 changed files with 513 additions and 30 deletions
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65
Userland/Utilities/wasm.cpp
View file

@ -16,16 +16,31 @@ int main(int argc, char* argv[])
const char* filename = nullptr;
bool print = false;
bool attempt_instantiate = false;
bool attemp_execute = false;
String exported_function_to_execute;
Vector<u64> values_to_push;
Core::ArgsParser parser;
parser.add_positional_argument(filename, "File name to parse", "file");
parser.add_option(print, "Print the parsed module", "print", 'p');
parser.add_option(attempt_instantiate, "Attempt to instantiate the module", "instantiate", 'i');
parser.add_option(attemp_execute, "Attempt to execute a function from the module (implies -i)", "execute", 'e');
parser.add_option(exported_function_to_execute, "Attempt to execute the named exported function from the module (implies -i)", "execute", 'e', "name");
parser.add_option(Core::ArgsParser::Option {
.requires_argument = true,
.help_string = "Supply arguments to the function (default=0) (expects u64, casts to required type)",
.long_name = "arg",
.short_name = 0,
.value_name = "u64",
.accept_value = [&](const char* str) -> bool {
if (auto v = StringView { str }.to_uint<u64>(); v.has_value()) {
values_to_push.append(v.value());
return true;
}
return false;
},
});
parser.parse(argc, argv);
if (attemp_execute)
if (!exported_function_to_execute.is_empty())
attempt_instantiate = true;
auto result = Core::File::open(filename, Core::OpenMode::ReadOnly);
@ -80,30 +95,40 @@ int main(int argc, char* argv[])
}
}
if (attemp_execute) {
if (!exported_function_to_execute.is_empty()) {
Optional<Wasm::FunctionAddress> run_address;
Vector<Wasm::Value> values;
// Pick a function that takes no args :P
for (auto& address : machine.module_instance().functions()) {
auto fn = machine.store().get(address);
if (!fn)
continue;
if (auto ptr = fn->get_pointer<Wasm::WasmFunction>()) {
const Wasm::FunctionType& ty = ptr->type();
for (auto& param : ty.parameters()) {
values.append(Wasm::Value { param, 0ull });
}
run_address = address;
break;
for (auto& entry : machine.module_instance().exports()) {
if (entry.name() == exported_function_to_execute) {
if (auto addr = entry.value().get_pointer<Wasm::FunctionAddress>())
run_address = *addr;
}
}
if (!run_address.has_value()) {
warnln("No nullary function, sorry :(");
warnln("No such exported function, sorry :(");
return 1;
}
outln("Executing ");
print_func(*run_address);
outln();
auto instance = machine.store().get(*run_address);
VERIFY(instance);
if (instance->has<Wasm::HostFunction>()) {
warnln("Exported function is a host function, cannot run that yet");
return 1;
}
for (auto& param : instance->get<Wasm::WasmFunction>().type().parameters()) {
if (values_to_push.is_empty())
values.append(Wasm::Value { param, 0ull });
else
values.append(Wasm::Value { param, values_to_push.take_last() });
}
if (print) {
outln("Executing ");
print_func(*run_address);
outln();
}
auto result = machine.invoke(run_address.value(), move(values));
if (!result.values().is_empty())