node-api,src: fix module registration in MSVC C++

PR-URL: #42459
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Michael Dawson <midawson@redhat.com>
Reviewed-By: Gerhard Stöbich <deb2001-github@yahoo.de>

Backport-PR-URL: #43293

src/node.h

@@ -824,11 +824,13 @@ extern "C" NODE_EXTERN void node_module_register(void* mod);
 #endif
 
 #if defined(_MSC_VER)
-#pragma section(".CRT$XCU", read)
 #define NODE_C_CTOR(fn)                                               \
   NODE_CTOR_PREFIX void __cdecl fn(void);                             \
-  __declspec(dllexport, allocate(".CRT$XCU"))                         \
-      void (__cdecl*fn ## _)(void) = fn;                              \
+  namespace {                                                         \
+  struct fn##_ {                                                      \
+    fn##_() { fn(); };                                                \
+  } fn##_v_;                                                          \
+  }                                                                   \
   NODE_CTOR_PREFIX void __cdecl fn(void)
 #else
 #define NODE_C_CTOR(fn)                                               \

src/node_api.h

@@ -44,12 +44,29 @@ typedef struct napi_module {
 #define NAPI_MODULE_VERSION  1
 
 #if defined(_MSC_VER)
+#if defined(__cplusplus)
+#define NAPI_C_CTOR(fn)                                                        \
+  static void __cdecl fn(void);                                                \
+  namespace {                                                                  \
+  struct fn##_ {                                                               \
+    fn##_() { fn(); }                                                          \
+  } fn##_v_;                                                                   \
+  }                                                                            \
+  static void __cdecl fn(void)
+#else  // !defined(__cplusplus)
 #pragma section(".CRT$XCU", read)
+// The NAPI_C_CTOR macro defines a function fn that is called during CRT
+// initialization.
+// C does not support dynamic initialization of static variables and this code
+// simulates C++ behavior. Exporting the function pointer prevents it from being
+// optimized. See for details:
+// https://docs.microsoft.com/en-us/cpp/c-runtime-library/crt-initialization?view=msvc-170
 #define NAPI_C_CTOR(fn)                                                     \
   static void __cdecl fn(void);                                             \
   __declspec(dllexport, allocate(".CRT$XCU")) void(__cdecl * fn##_)(void) = \
       fn;                                                                   \
   static void __cdecl fn(void)
+#endif  // defined(__cplusplus)
 #else
 #define NAPI_C_CTOR(fn)                              \
   static void fn(void) __attribute__((constructor)); \

test/js-native-api/common.h

@@ -62,6 +62,9 @@
 #define DECLARE_NODE_API_GETTER(name, func)                              \
   { (name), NULL, NULL, (func), NULL, NULL, napi_default, NULL }
 
+#define DECLARE_NODE_API_PROPERTY_VALUE(name, value)                     \
+  { (name), NULL, NULL, NULL, NULL, (value), napi_default, NULL }
+
 void add_returned_status(napi_env env,
                          const char* key,
                          napi_value object,

test/node-api/test_init_order/binding.gyp

@@ -0,0 +1,8 @@
+{
+  "targets": [
+    {
+      "target_name": "test_init_order",
+      "sources": [ "test_init_order.cc" ]
+    }
+  ]
+}

test/node-api/test_init_order/test.js

@@ -0,0 +1,10 @@
+'use strict';
+
+// This test verifies that C++ static variable dynamic initialization is called
+// correctly and does not interfere with the module initialization.
+const common = require('../../common');
+const test_init_order = require(`./build/${common.buildType}/test_init_order`);
+const assert = require('assert');
+
+assert.strictEqual(test_init_order.cppIntValue, 42);
+assert.strictEqual(test_init_order.cppStringValue, '123');

test/node-api/test_init_order/test_init_order.cc

@@ -0,0 +1,55 @@
+#include <node_api.h>
+#include <memory>
+#include <string>
+#include "../../js-native-api/common.h"
+
+// This test verifies that use of the NAPI_MODULE in C++ code does not
+// interfere with the C++ dynamic static initializers.
+
+namespace {
+
+// This class uses dynamic static initializers for the test.
+// In production code developers must avoid dynamic static initializers because
+// they affect the start up time. They must prefer static initialization such as
+// use of constexpr functions or classes with constexpr constructors. E.g.
+// instead of using std::string, it is preferrable to use const char[], or
+// constexpr std::string_view starting with C++17, or even constexpr
+// std::string starting with C++20.
+struct MyClass {
+  static const std::unique_ptr<int> valueHolder;
+  static const std::string testString;
+};
+
+const std::unique_ptr<int> MyClass::valueHolder =
+    std::unique_ptr<int>(new int(42));
+// NOLINTNEXTLINE(runtime/string)
+const std::string MyClass::testString = std::string("123");
+
+}  // namespace
+
+EXTERN_C_START
+napi_value Init(napi_env env, napi_value exports) {
+  napi_value cppIntValue, cppStringValue;
+  NODE_API_CALL(env,
+                napi_create_int32(env, *MyClass::valueHolder, &cppIntValue));
+  NODE_API_CALL(
+      env,
+      napi_create_string_utf8(
+          env, MyClass::testString.c_str(), NAPI_AUTO_LENGTH, &cppStringValue));
+
+  napi_property_descriptor descriptors[] = {
+      DECLARE_NODE_API_PROPERTY_VALUE("cppIntValue", cppIntValue),
+      DECLARE_NODE_API_PROPERTY_VALUE("cppStringValue", cppStringValue)};
+
+  NODE_API_CALL(
+      env,
+      napi_define_properties(env,
+                             exports,
+                             sizeof(descriptors) / sizeof(descriptors[0]),
+                             descriptors));
+
+  return exports;
+}
+EXTERN_C_END
+
+NAPI_MODULE(NODE_GYP_MODULE_NAME, Init)