build: fix various shared library build issues

Node.js unofficially supports a shared library variant where the
main node executable is a thin wrapper around node.dll/libnode.so.
The key benefit of this is to support embedding Node.js in other
applications.

Since Node.js 12 there have been a number of issues preventing the
shared library build from working correctly, primarily on Windows:

* A number of functions used executables such as `mksnapshot` are
    not exported from `libnode.dll` using a `NODE_EXTERN` attribute
* A dependency on the `Winmm` system library is missing
* Incorrect defines on executable targets leads to `node.exe`
    claiming to export a number of functions that are actually in
    `libnode.dll`
* Because `node.exe` attempts to export symbols, `node.lib` gets
    generated causing native extensions to try to link against
    `node.exe` not `libnode.dll`.
* Similarly, because `node.dll` was renamed to `libnode.dll`,
    native extensions don't know to look for `libnode.lib` rather
    than `node.lib`.
* On macOS an RPATH is added to find `libnode.dylib` relative to
    `node` in the same folder. This works fine from the
    `out/Release` folder but not from an installed prefix, where
    `node` will be in `bin/` and `libnode.dylib` will be in `lib/`.
* Similarly on Linux, no RPATH is added so LD_LIBRARY_PATH needs
    setting correctly for `bin/node` to find `lib/libnode.so`.

For the `libnode.lib` vs `node.lib` issue there are two possible
options:

1. Ensure `node.lib` from `node.exe` does not get generated, and
    instead copy `libnode.lib` to `node.lib`. This means addons
    compiled when referencing the correct `node.lib` file will
    correctly depend on `libnode.dll`. The down side is that
    native addons compiled with stock Node.js will still try to
    resolve symbols against node.exe rather than libnode.dll.
2. After building `libnode.dll`, dump the exports using `dumpbin`,
    and process this to generate a `node.def` file to be linked into
    `node.exe` with the `/DEF:node.def` flag. The export entries
    in `node.def` will all read
    ```
    my_symbol=libnode.my_symbol
    ```
    so that `node.exe` will redirect all exported symbols back to
    `libnode.dll`. This has the benefit that addons compiled with
    stock Node.js will load correctly into `node.exe` from a shared
    library build, but means that every embedding executable also
    needs to perform this same trick.

I went with the first option as it is the cleaner of the two
solutions in my opinion. Projects wishing to generate a shared
library variant of Node.js can now, for example,
```
.\vcbuild dll package vs
```
to generate a full node installation including `libnode.dll`,
`Release\node.lib`, and all the necessary headers. Native addons
can then be built against the shared library build easily by
specifying the correct `nodedir` option.

For example
```
>npx node-gyp configure --nodedir
   C:\Users\User\node\Release\node-v18.0.0-win-x64
...
>npx node-gyp build
...
>dumpbin /dependents build\Release\binding.node
Microsoft (R) COFF/PE Dumper Version 14.29.30136.0
Copyright (C) Microsoft Corporation.  All rights reserved.

Dump of file build\Release\binding.node

File Type: DLL

  Image has the following dependencies:

    KERNEL32.dll
    libnode.dll
    VCRUNTIME140.dll
    api-ms-win-crt-string-l1-1-0.dll
    api-ms-win-crt-stdio-l1-1-0.dll
    api-ms-win-crt-runtime-l1-1-0.dll
...
```

PR-URL: #41850
Reviewed-By: Michael Dawson <[email protected]>
Reviewed-By: Beth Griggs <[email protected]>
Reviewed-By: Richard Lau <[email protected]>

node.gyp

@@ -196,6 +196,16 @@
           'dependencies': [ 'node_aix_shared' ],
         }, {
           'dependencies': [ '<(node_lib_target_name)' ],
+          'conditions': [
+            ['OS=="win" and node_shared=="true"', {
+              'dependencies': ['generate_node_def'],
+              'msvs_settings': {
+                'VCLinkerTool': {
+                  'ModuleDefinitionFile': '<(PRODUCT_DIR)/<(node_core_target_name).def',
+                },
+              },
+            }],
+          ],
         }],
         [ 'node_intermediate_lib_type=="static_library" and node_shared=="false"', {
           'xcode_settings': {
@@ -235,8 +245,15 @@
         }],
         [ 'node_shared=="true"', {
           'xcode_settings': {
-            'OTHER_LDFLAGS': [ '-Wl,-rpath,@loader_path', ],
+            'OTHER_LDFLAGS': [ '-Wl,-rpath,@loader_path', '-Wl,-rpath,@loader_path/../lib'],
           },
+          'conditions': [
+            ['OS=="linux"', {
+               'ldflags': [
+                 '-Wl,-rpath,\\$$ORIGIN/../lib'
+               ],
+            }],
+          ],
         }],
         [ 'enable_lto=="true"', {
           'xcode_settings': {
@@ -666,6 +683,7 @@
           'libraries': [
             'Dbghelp',
             'Psapi',
+            'Winmm',
             'Ws2_32',
           ],
         }],
@@ -1419,5 +1437,40 @@
         },
       ]
     }], # end aix section
+    ['OS=="win" and node_shared=="true"', {
+     'targets': [
+       {
+         'target_name': 'gen_node_def',
+         'type': 'executable',
+         'sources': [
+           'tools/gen_node_def.cc'
+         ],
+       },
+       {
+         'target_name': 'generate_node_def',
+         'dependencies': [
+           'gen_node_def',
+           '<(node_lib_target_name)',
+         ],
+         'type': 'none',
+         'actions': [
+           {
+             'action_name': 'generate_node_def_action',
+             'inputs': [
+               '<(PRODUCT_DIR)/<(node_lib_target_name).dll'
+             ],
+             'outputs': [
+               '<(PRODUCT_DIR)/<(node_core_target_name).def',
+             ],
+             'action': [
+               '<(PRODUCT_DIR)/gen_node_def.exe',
+               '<@(_inputs)',
+               '<@(_outputs)',
+             ],
+           },
+         ],
+       },
+     ],
+   }], # end win section
   ], # end conditions block
 }

node.gypi

@@ -29,7 +29,7 @@
     [ 'clang==1', {
       'cflags': [ '-Werror=undefined-inline', ]
     }],
-    [ 'node_shared=="false" and "<(_type)"=="executable"', {
+    [ '"<(_type)"=="executable"', {
       'msvs_settings': {
         'VCManifestTool': {
           'EmbedManifest': 'true',
@@ -41,6 +41,19 @@
       'defines': [
         'NODE_SHARED_MODE',
       ],
+      'conditions': [
+        ['"<(_type)"=="executable"', {
+          'defines': [
+            'USING_UV_SHARED',
+            'USING_V8_SHARED',
+            'BUILDING_NODE_EXTENSION'
+          ],
+          'defines!': [
+            'BUILDING_V8_SHARED=1',
+            'BUILDING_UV_SHARED=1'
+          ]
+        }],
+      ],
     }],
     [ 'OS=="win"', {
       'defines!': [

src/debug_utils.h

@@ -35,7 +35,7 @@ template <typename... Args>
 inline std::string SPrintF(const char* format, Args&&... args);
 template <typename... Args>
 inline void FPrintF(FILE* file, const char* format, Args&&... args);
-void FWrite(FILE* file, const std::string& str);
+void NODE_EXTERN_PRIVATE FWrite(FILE* file, const std::string& str);
 
 // Listing the AsyncWrap provider types first enables us to cast directly
 // from a provider type to a debug category.
@@ -57,7 +57,7 @@ enum class DebugCategory {
       CATEGORY_COUNT
 };
 
-class EnabledDebugList {
+class NODE_EXTERN_PRIVATE EnabledDebugList {
  public:
   bool enabled(DebugCategory category) const {
     DCHECK_GE(static_cast<int>(category), 0);
@@ -168,7 +168,7 @@ void CheckedUvLoopClose(uv_loop_t* loop);
 void PrintLibuvHandleInformation(uv_loop_t* loop, FILE* stream);
 
 namespace per_process {
-extern EnabledDebugList enabled_debug_list;
+extern NODE_EXTERN_PRIVATE EnabledDebugList enabled_debug_list;
 
 template <typename... Args>
 inline void FORCE_INLINE Debug(DebugCategory cat,

src/env.h

@@ -558,7 +558,7 @@ class Environment;
 struct AllocatedBuffer;
 
 typedef size_t SnapshotIndex;
-class IsolateData : public MemoryRetainer {
+class NODE_EXTERN_PRIVATE IsolateData : public MemoryRetainer {
  public:
   IsolateData(v8::Isolate* isolate,
               uv_loop_t* event_loop,

src/node.h

@@ -32,6 +32,16 @@
 # define NODE_EXTERN __attribute__((visibility("default")))
 #endif
 
+// Declarations annotated with NODE_EXTERN_PRIVATE do not form part of
+// the public API. They are implementation details that can and will
+// change between releases, even in semver patch releases. Do not use
+// any such symbol in external code.
+#ifdef NODE_SHARED_MODE
+#define NODE_EXTERN_PRIVATE NODE_EXTERN
+#else
+#define NODE_EXTERN_PRIVATE
+#endif
+
 #ifdef BUILDING_NODE_EXTENSION
 # undef BUILDING_V8_SHARED
 # undef BUILDING_UV_SHARED

src/node_internals.h

@@ -320,13 +320,14 @@ enum InitializationSettingsFlags : uint64_t {
 };
 
 // TODO(codebytere): eventually document and expose to embedders.
-InitializationResult InitializeOncePerProcess(int argc, char** argv);
-InitializationResult InitializeOncePerProcess(
-  int argc,
-  char** argv,
-  InitializationSettingsFlags flags,
-  ProcessFlags::Flags process_flags = ProcessFlags::kNoFlags);
-void TearDownOncePerProcess();
+InitializationResult NODE_EXTERN_PRIVATE InitializeOncePerProcess(int argc,
+                                                                  char** argv);
+InitializationResult NODE_EXTERN_PRIVATE InitializeOncePerProcess(
+    int argc,
+    char** argv,
+    InitializationSettingsFlags flags,
+    ProcessFlags::Flags process_flags = ProcessFlags::kNoFlags);
+void NODE_EXTERN_PRIVATE TearDownOncePerProcess();
 void SetIsolateErrorHandlers(v8::Isolate* isolate, const IsolateSettings& s);
 void SetIsolateMiscHandlers(v8::Isolate* isolate, const IsolateSettings& s);
 void SetIsolateCreateParamsForNode(v8::Isolate::CreateParams* params);

src/node_native_module.h

@@ -29,7 +29,7 @@ using NativeModuleCacheMap =
 // This class should not depend on any Environment, or depend on access to
 // the its own singleton - that should be encapsulated in NativeModuleEnv
 // instead.
-class NativeModuleLoader {
+class NODE_EXTERN_PRIVATE NativeModuleLoader {
  public:
   NativeModuleLoader(const NativeModuleLoader&) = delete;
   NativeModuleLoader& operator=(const NativeModuleLoader&) = delete;

src/node_options.h

@@ -478,7 +478,7 @@ void Parse(
 namespace per_process {
 
 extern Mutex cli_options_mutex;
-extern std::shared_ptr<PerProcessOptions> cli_options;
+extern NODE_EXTERN_PRIVATE std::shared_ptr<PerProcessOptions> cli_options;
 
 }  // namespace per_process
 

src/node_snapshot_builder.h

@@ -13,7 +13,7 @@ namespace node {
 class ExternalReferenceRegistry;
 struct SnapshotData;
 
-class SnapshotBuilder {
+class NODE_EXTERN_PRIVATE SnapshotBuilder {
  public:
   static std::string Generate(const std::vector<std::string> args,
                               const std::vector<std::string> exec_args);

src/util.h

@@ -26,6 +26,8 @@
 
 #include "v8.h"
 
+#include "node.h"
+
 #include <climits>
 #include <cstddef>
 #include <cstdio>
@@ -108,8 +110,8 @@ struct AssertionInfo {
   const char* message;
   const char* function;
 };
-[[noreturn]] void Assert(const AssertionInfo& info);
-[[noreturn]] void Abort();
+[[noreturn]] void NODE_EXTERN_PRIVATE Assert(const AssertionInfo& info);
+[[noreturn]] void NODE_EXTERN_PRIVATE Abort();
 void DumpBacktrace(FILE* fp);
 
 // Windows 8+ does not like abort() in Release mode