[wasm-c-api] Add upstream examples as tests

Plus a script to compile/link/run them.

Change-Id: Iac8ffcda3a73902261c07a7b4e5d967a19414c75
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1564058
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60911}

third_party/wasm-api/README.v8

@@ -13,5 +13,5 @@ Provides a "black box" API for embedding a Wasm engine in C/C++ applications.
 
 Local modifications:
 None.
-This is only the contents of the "include/" directory of the upstream
-repository.
+The contents of the upstream "include/" directory are directly in here.
+The upstream "example/" directory is copied as-is.

third_party/wasm-api/example/callback.c

@@ -0,0 +1,167 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <inttypes.h>
+
+#include "wasm.h"
+
+#define own
+
+// Print a Wasm value
+void wasm_val_print(wasm_val_t val) {
+  switch (val.kind) {
+    case WASM_I32: {
+      printf("%" PRIu32, val.of.i32);
+    } break;
+    case WASM_I64: {
+      printf("%" PRIu64, val.of.i64);
+    } break;
+    case WASM_F32: {
+      printf("%f", val.of.f32);
+    } break;
+    case WASM_F64: {
+      printf("%g", val.of.f64);
+    } break;
+    case WASM_ANYREF:
+    case WASM_FUNCREF: {
+      if (val.of.ref == NULL) {
+        printf("null");
+      } else {
+        printf("ref(%p)", val.of.ref);
+      }
+    } break;
+  }
+}
+
+// A function to be called from Wasm code.
+own wasm_trap_t* print_callback(
+  const wasm_val_t args[], wasm_val_t results[]
+) {
+  printf("Calling back...\n> ");
+  wasm_val_print(args[0]);
+  printf("\n");
+
+  wasm_val_copy(&results[0], &args[0]);
+  return NULL;
+}
+
+
+// A function closure.
+own wasm_trap_t* closure_callback(
+  void* env, const wasm_val_t args[], wasm_val_t results[]
+) {
+  int i = *(int*)env;
+  printf("Calling back closure...\n");
+  printf("> %d\n", i);
+
+  results[0].kind = WASM_I32;
+  results[0].of.i32 = (int32_t)i;
+  return NULL;
+}
+
+
+int main(int argc, const char* argv[]) {
+  // Initialize.
+  printf("Initializing...\n");
+  wasm_engine_t* engine = wasm_engine_new();
+  wasm_store_t* store = wasm_store_new(engine);
+
+  // Load binary.
+  printf("Loading binary...\n");
+  FILE* file = fopen("callback.wasm", "r");
+  if (!file) {
+    printf("> Error loading module!\n");
+    return 1;
+  }
+  fseek(file, 0L, SEEK_END);
+  size_t file_size = ftell(file);
+  fseek(file, 0L, SEEK_SET);
+  wasm_byte_vec_t binary;
+  wasm_byte_vec_new_uninitialized(&binary, file_size);
+  if (fread(binary.data, file_size, 1, file) != 1) {
+    printf("> Error loading module!\n");
+    return 1;
+  }
+  fclose(file);
+
+  // Compile.
+  printf("Compiling module...\n");
+  own wasm_module_t* module = wasm_module_new(store, &binary);
+  if (!module) {
+    printf("> Error compiling module!\n");
+    return 1;
+  }
+
+  wasm_byte_vec_delete(&binary);
+
+  // Create external print functions.
+  printf("Creating callback...\n");
+  own wasm_functype_t* print_type = wasm_functype_new_1_1(wasm_valtype_new_i32(), wasm_valtype_new_i32());
+  own wasm_func_t* print_func = wasm_func_new(store, print_type, print_callback);
+
+  int i = 42;
+  own wasm_functype_t* closure_type = wasm_functype_new_0_1(wasm_valtype_new_i32());
+  own wasm_func_t* closure_func = wasm_func_new_with_env(store, closure_type, closure_callback, &i, NULL);
+
+  wasm_functype_delete(print_type);
+  wasm_functype_delete(closure_type);
+
+  // Instantiate.
+  printf("Instantiating module...\n");
+  const wasm_extern_t* imports[] = {
+    wasm_func_as_extern(print_func), wasm_func_as_extern(closure_func)
+  };
+  own wasm_instance_t* instance = wasm_instance_new(store, module, imports);
+  if (!instance) {
+    printf("> Error instantiating module!\n");
+    return 1;
+  }
+
+  wasm_func_delete(print_func);
+  wasm_func_delete(closure_func);
+
+  // Extract export.
+  printf("Extracting export...\n");
+  own wasm_extern_vec_t exports;
+  wasm_instance_exports(instance, &exports);
+  if (exports.size == 0) {
+    printf("> Error accessing exports!\n");
+    return 1;
+  }
+  const wasm_func_t* run_func = wasm_extern_as_func(exports.data[0]);
+  if (run_func == NULL) {
+    printf("> Error accessing export!\n");
+    return 1;
+  }
+
+  wasm_module_delete(module);
+  wasm_instance_delete(instance);
+
+  // Call.
+  printf("Calling export...\n");
+  wasm_val_t args[2];
+  args[0].kind = WASM_I32;
+  args[0].of.i32 = 3;
+  args[1].kind = WASM_I32;
+  args[1].of.i32 = 4;
+  wasm_val_t results[1];
+  if (wasm_func_call(run_func, args, results)) {
+    printf("> Error calling function!\n");
+    return 1;
+  }
+
+  wasm_extern_vec_delete(&exports);
+
+  // Print result.
+  printf("Printing result...\n");
+  printf("> %u\n", results[0].of.i32);
+
+  // Shut down.
+  printf("Shutting down...\n");
+  wasm_store_delete(store);
+  wasm_engine_delete(engine);
+
+  // All done.
+  printf("Done.\n");
+  return 0;
+}

third_party/wasm-api/example/callback.cc

@@ -0,0 +1,145 @@
+#include <iostream>
+#include <fstream>
+#include <cstdlib>
+#include <string>
+#include <cinttypes>
+
+#include "wasm.hh"
+
+// Print a Wasm value
+auto operator<<(std::ostream& out, const wasm::Val& val) -> std::ostream& {
+  switch (val.kind()) {
+    case wasm::I32: {
+      out << val.i32();
+    } break;
+    case wasm::I64: {
+      out << val.i64();
+    } break;
+    case wasm::F32: {
+      out << val.f32();
+    } break;
+    case wasm::F64: {
+      out << val.f64();
+    } break;
+    case wasm::ANYREF:
+    case wasm::FUNCREF: {
+      if (val.ref() == nullptr) {
+        out << "null";
+      } else {
+        out << "ref(" << val.ref() << ")";
+      }
+    } break;
+  }
+  return out;
+}
+
+// A function to be called from Wasm code.
+auto print_callback(
+  const wasm::Val args[], wasm::Val results[]
+) -> wasm::own<wasm::Trap*> {
+  std::cout << "Calling back..." << std::endl << "> " << args[0] << std::endl;
+  results[0] = args[0].copy();
+  return nullptr;
+}
+
+
+// A function closure.
+auto closure_callback(
+  void* env, const wasm::Val args[], wasm::Val results[]
+) -> wasm::own<wasm::Trap*> {
+  auto i = *reinterpret_cast<int*>(env);
+  std::cout << "Calling back closure..." << std::endl;
+  std::cout << "> " << i << std::endl;
+  results[0] = wasm::Val::i32(static_cast<int32_t>(i));
+  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("callback.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;
+    return;
+  }
+
+  // Compile.
+  std::cout << "Compiling module..." << std::endl;
+  auto module = wasm::Module::make(store, binary);
+  if (!module) {
+    std::cout << "> Error compiling module!" << std::endl;
+    return;
+  }
+
+  // Create external print functions.
+  std::cout << "Creating callback..." << std::endl;
+  auto print_type = wasm::FuncType::make(
+    wasm::vec<wasm::ValType*>::make(wasm::ValType::make(wasm::I32)),
+    wasm::vec<wasm::ValType*>::make(wasm::ValType::make(wasm::I32))
+  );
+  auto print_func = wasm::Func::make(store, print_type.get(), print_callback);
+
+  // Creating closure.
+  std::cout << "Creating closure..." << std::endl;
+  int i = 42;
+  auto closure_type = wasm::FuncType::make(
+    wasm::vec<wasm::ValType*>::make(),
+    wasm::vec<wasm::ValType*>::make(wasm::ValType::make(wasm::I32))
+  );
+  auto closure_func = wasm::Func::make(store, closure_type.get(), closure_callback, &i);
+
+  // Instantiate.
+  std::cout << "Instantiating module..." << std::endl;
+  wasm::Extern* imports[] = {print_func.get(), closure_func.get()};
+  auto instance = wasm::Instance::make(store, module.get(), imports);
+  if (!instance) {
+    std::cout << "> Error instantiating module!" << std::endl;
+    return;
+  }
+
+  // Extract export.
+  std::cout << "Extracting export..." << std::endl;
+  auto exports = instance->exports();
+  if (exports.size() == 0 || exports[0]->kind() != wasm::EXTERN_FUNC || !exports[0]->func()) {
+    std::cout << "> Error accessing export!" << std::endl;
+    return;
+  }
+  auto run_func = exports[0]->func();
+
+  // Call.
+  std::cout << "Calling export..." << std::endl;
+  wasm::Val args[] = {wasm::Val::i32(3), wasm::Val::i32(4)};
+  wasm::Val results[1];
+  if (run_func->call(args, results)) {
+    std::cout << "> Error calling function!" << std::endl;
+    return;
+  }
+
+  // Print result.
+  std::cout << "Printing result..." << std::endl;
+  std::cout << "> " << results[0].i32() << std::endl;
+
+  // Shut down.
+  std::cout << "Shutting down..." << std::endl;
+}
+
+
+int main(int argc, const char* argv[]) {
+  run();
+  std::cout << "Done." << std::endl;
+  return 0;
+}
+

third_party/wasm-api/example/callback.wat

@@ -0,0 +1,10 @@
+(module
+  (func $print (import "" "print") (param i32) (result i32))
+  (func $closure (import "" "closure") (result i32))
+  (func (export "run") (param $x i32) (param $y i32) (result i32)
+    (i32.add
+      (call $print (i32.add (local.get $x) (local.get $y)))
+      (call $closure)
+    )
+  )
+)