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#include <iostream>
#include <fstream>
#include <cstdlib>
#include <string>
#include <cinttypes>
#include "wasm.hh"
// A function to be called from Wasm code.
auto hello_callback(
const wasm::Val args[], wasm::Val results[]
) -> wasm::own<wasm::Trap> {
std::cout << "Calling back..." << std::endl;
std::cout << "> Hello world!" << std::endl;
return nullptr;
}
void run() {
// Initialize.
std::cout << "Initializing..." << std::endl;
auto engine = wasm::Engine::make();
auto store_ = wasm::Store::make(engine.get());
auto store = store_.get();
// Load binary.
std::cout << "Loading binary..." << std::endl;
std::ifstream file("hello.wasm");
file.seekg(0, std::ios_base::end);
auto file_size = file.tellg();
file.seekg(0);
auto binary = wasm::vec<byte_t>::make_uninitialized(file_size);
file.read(binary.get(), file_size);
file.close();
if (file.fail()) {
std::cout << "> Error loading module!" << std::endl;
exit(1);
}
// Compile.
std::cout << "Compiling module..." << std::endl;
auto module = wasm::Module::make(store, binary);
if (!module) {
std::cout << "> Error compiling module!" << std::endl;
exit(1);
}
// Create external print functions.
std::cout << "Creating callback..." << std::endl;
auto hello_type = wasm::FuncType::make(
wasm::ownvec<wasm::ValType>::make(), wasm::ownvec<wasm::ValType>::make()
);
auto hello_func = wasm::Func::make(store, hello_type.get(), hello_callback);
// Instantiate.
std::cout << "Instantiating module..." << std::endl;
wasm::Extern* imports[] = {hello_func.get()};
auto instance = wasm::Instance::make(store, module.get(), imports);
if (!instance) {
std::cout << "> Error instantiating module!" << std::endl;
exit(1);
}
// Extract export.
std::cout << "Extracting export..." << std::endl;
auto exports = instance->exports();
if (exports.size() == 0 || exports[0]->kind() != wasm::ExternKind::FUNC || !exports[0]->func()) {
std::cout << "> Error accessing export!" << std::endl;
exit(1);
}
auto run_func = exports[0]->func();
// Call.
std::cout << "Calling export..." << std::endl;
if (run_func->call()) {
std::cout << "> Error calling function!" << std::endl;
exit(1);
}
// Shut down.
std::cout << "Shutting down..." << std::endl;
}
int main(int argc, const char* argv[]) {
run();
std::cout << "Done." << std::endl;
return 0;
}
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