[native_toolchain_c] Add Linking for Windows (#2367)

Author: goderbauer

pkgs/native_toolchain_c/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.16.6
+
+* Support linking for Windows.
+
 ## 0.16.5
 
 * Support linking for iOS.

pkgs/native_toolchain_c/lib/src/cbuilder/clinker.dart

@@ -18,8 +18,6 @@ import 'output_type.dart';
 import 'run_cbuilder.dart';
 
 /// Specification for linking an artifact with a C linker.
-//TODO(mosuem): This is currently only implemented for linux.
-// See also https://github.com/dart-lang/native/issues/1376
 class CLinker extends CTool implements Linker {
   final LinkerOptions linkerOptions;
 
@@ -53,14 +51,6 @@ class CLinker extends CTool implements Linker {
     required LinkOutputBuilder output,
     required Logger? logger,
   }) async {
-    const supportedTargetOSs = [OS.linux, OS.android, OS.macOS, OS.iOS];
-    if (!supportedTargetOSs.contains(input.config.code.targetOS)) {
-      throw UnsupportedError(
-        'This feature is only supported when targeting '
-        '${supportedTargetOSs.join(', ')}. '
-        'See also https://github.com/dart-lang/native/issues/1376',
-      );
-    }
     final outDir = input.outputDirectory;
     final packageRoot = input.packageRoot;
     await Directory.fromUri(outDir).create(recursive: true);

pkgs/native_toolchain_c/lib/src/cbuilder/linker_options.dart

@@ -6,6 +6,7 @@ import 'dart:io';
 
 import 'package:code_assets/code_assets.dart';
 
+import '../native_toolchain/msvc.dart';
 import '../native_toolchain/tool_likeness.dart';
 import '../tool/tool.dart';
 
@@ -94,15 +95,35 @@ extension LinkerOptionsExt on LinkerOptions {
     Tool tool,
     Iterable<String> sourceFiles,
     OS targetOS,
+    Architecture targetArchitecture,
   ) {
-    final includeAllSymbols = _symbolsToKeep == null;
+    if (tool.isClangLike || tool.isLdLike) {
+      return _sourceFilesToFlagsForClangLike(tool, sourceFiles, targetOS);
+    } else if (tool == cl) {
+      return _sourceFilesToFlagsForCl(
+        tool,
+        sourceFiles,
+        targetOS,
+        targetArchitecture,
+      );
+    } else {
+      throw UnimplementedError('This package does not know how to run $tool.');
+    }
+  }
 
+  bool get _includeAllSymbols => _symbolsToKeep == null;
+
+  Iterable<String> _sourceFilesToFlagsForClangLike(
+    Tool tool,
+    Iterable<String> sourceFiles,
+    OS targetOS,
+  ) {
     switch (targetOS) {
       case OS.macOS || OS.iOS:
         return [
-          if (!includeAllSymbols) ...sourceFiles,
+          if (!_includeAllSymbols) ...sourceFiles,
           ..._toLinkerSyntax(tool, [
-            if (includeAllSymbols) ...sourceFiles.map((e) => '-force_load,$e'),
+            if (_includeAllSymbols) ...sourceFiles.map((e) => '-force_load,$e'),
             ..._linkerFlags,
             ..._symbolsToKeep?.map((symbol) => '-u,_$symbol') ?? [],
             if (stripDebug) '-S',
@@ -113,7 +134,7 @@ extension LinkerOptionsExt on LinkerOptions {
       case OS.android || OS.linux:
         final wholeArchiveSandwich =
             sourceFiles.any((source) => source.endsWith('.a')) ||
-            includeAllSymbols;
+            _includeAllSymbols;
         return [
           if (wholeArchiveSandwich)
             ..._toLinkerSyntax(tool, ['--whole-archive']),
@@ -132,4 +153,23 @@ extension LinkerOptionsExt on LinkerOptions {
         throw UnimplementedError();
     }
   }
+
+  Iterable<String> _sourceFilesToFlagsForCl(
+    Tool tool,
+    Iterable<String> sourceFiles,
+    OS targetOS,
+    Architecture targetArch,
+  ) => [
+    ...sourceFiles,
+    '/link',
+    if (_includeAllSymbols) ...sourceFiles.map((e) => '/WHOLEARCHIVE:$e'),
+    ..._linkerFlags,
+    ..._symbolsToKeep?.map(
+          (symbol) =>
+              '/INCLUDE:${targetArch == Architecture.ia32 ? '_' : ''}$symbol',
+        ) ??
+        [],
+    if (stripDebug) '/PDBSTRIPPED',
+    if (gcSections) '/OPT:REF',
+  ];
 }

pkgs/native_toolchain_c/lib/src/cbuilder/run_cbuilder.dart

@@ -310,6 +310,7 @@ class RunCBuilder {
             toolInstance.tool,
             sourceFiles,
             codeConfig.targetOS,
+            codeConfig.targetArchitecture,
           )
         else
           ...sourceFiles,
@@ -353,6 +354,7 @@ class RunCBuilder {
     if (isStaticLib) {
       archiver_ = await archiver();
     }
+    final sourceFiles = sources.map((e) => e.toFilePath());
 
     final result = await runProcess(
       executable: tool.uri,
@@ -368,18 +370,25 @@ class RunCBuilder {
         for (final forcedInclude in forcedIncludes)
           '/FI${forcedInclude.toFilePath()}',
         if (executable != null) ...[
-          ...sources.map((e) => e.toFilePath()),
-          '/link',
-          '/out:${outDir.resolveUri(executable!).toFilePath()}',
+          '/Fe:${outDir.resolveUri(executable!).toFilePath()}',
         ] else if (dynamicLibrary != null) ...[
-          ...sources.map((e) => e.toFilePath()),
-          '/link',
-          '/DLL',
-          '/out:${outDir.resolveUri(dynamicLibrary!).toFilePath()}',
+          '/LD',
+          '/Fe:${outDir.resolveUri(dynamicLibrary!).toFilePath()}',
         ] else if (staticLibrary != null) ...[
           '/c',
-          ...sources.map((e) => e.toFilePath()),
         ],
+        if (linkerOptions != null)
+          ...linkerOptions!.sourceFilesToFlags(
+            tool.tool,
+            sourceFiles,
+            codeConfig.targetOS,
+            codeConfig.targetArchitecture,
+          )
+        else ...[
+          ...sourceFiles,
+          '/link',
+        ],
+        '/MACHINE:${clTargetFlags[codeConfig.targetArchitecture]}',
         if (executable != null || dynamicLibrary != null) ...[
           for (final directory in libraryDirectories)
             '/LIBPATH:${directory.toFilePath()}',
@@ -435,6 +444,12 @@ class RunCBuilder {
     Architecture.x64: 'x86_64-pc-windows-msvc',
   };
 
+  static const clTargetFlags = {
+    Architecture.arm64: 'ARM64',
+    Architecture.ia32: 'X86',
+    Architecture.x64: 'X64',
+  };
+
   static const defaultCppLinkStdLib = {
     OS.android: 'c++_shared',
     OS.fuchsia: 'c++',

pkgs/native_toolchain_c/pubspec.yaml

@@ -1,7 +1,7 @@
 name: native_toolchain_c
 description: >-
   A library to invoke the native C compiler installed on the host machine.
-version: 0.16.5
+version: 0.16.6
 repository: https://github.com/dart-lang/native/tree/main/pkgs/native_toolchain_c
 
 topics:

pkgs/native_toolchain_c/test/clinker/objects_cross_test.dart

@@ -2,25 +2,12 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// TODO(mosuem): Enable for windows.
-// See https://github.com/dart-lang/native/issues/1376.
-@TestOn('linux || mac-os')
-library;
-
-import 'dart:io';
-
 import 'package:code_assets/code_assets.dart';
-import 'package:test/test.dart';
 
 import '../helpers.dart';
 import 'objects_helper.dart';
 
 void main() {
-  if (!Platform.isLinux && !Platform.isMacOS) {
-    // Avoid needing status files on Dart SDK CI.
-    return;
-  }
-
   final architectures = supportedArchitecturesFor(OS.current)
     ..remove(Architecture.current); // See objects_test.dart for current arch.
 

pkgs/native_toolchain_c/test/clinker/objects_helper.dart

@@ -95,7 +95,7 @@ void runObjectsTests(
       final asset = codeAssets.first;
       expect(asset, isA<CodeAsset>());
       expect(
-        await nmReadSymbols(asset, targetOS),
+        await readSymbols(asset, targetOS),
         stringContainsInOrder(['my_func', 'my_other_func']),
       );
     });

pkgs/native_toolchain_c/test/clinker/objects_test.dart

@@ -2,25 +2,12 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// TODO(mosuem): Enable for windows.
-// See https://github.com/dart-lang/native/issues/1376.
-@TestOn('linux || mac-os')
-library;
-
-import 'dart:io';
-
 import 'package:code_assets/code_assets.dart';
-import 'package:test/test.dart';
 
 import '../helpers.dart';
 import 'objects_helper.dart';
 
 void main() {
-  if (!Platform.isLinux && !Platform.isMacOS) {
-    // Avoid needing status files on Dart SDK CI.
-    return;
-  }
-
   runObjectsTests(
     OS.current,
     [Architecture.current],

pkgs/native_toolchain_c/test/clinker/testfiles/linker/test1.c

@@ -1,6 +1,21 @@
 #include <stdio.h>
 
-void my_func()
+#if _WIN32
+#define FFI_EXPORT __declspec(dllexport)
+#else
+#define FFI_EXPORT
+#endif
+
+FFI_EXPORT void my_func()
 {
-  printf("42");
+  // Using a long (512B) string here so that treeshaking this function actually affects binary size on disk.
+  // On windows, treeshaking just a small string (<512B) out of a binary has no effect on raw size because of padding
+  // and alignment (FileAlignment of sections defaults to 512B in a Windows DLL).
+  printf(
+    "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Duis dui lacus, volutpat nec consequat at, hendrerit et "
+    "lorem. Etiam porttitor velit massa, vitae aliquet elit bibendum quis. Vivamus vestibulum ligula ac nisl faucibus "
+    "convallis. Morbi accumsan elit vel varius gravida. Ut nec interdum sapien, vitae mattis libero. Donec ac placerat "
+    "lorem. Proin mattis mauris et felis consectetur, et tempor diam tincidunt. Nunc malesuada massa at lectus "
+    "volutpat, luctus congue lectus facilisis. Vivamus in cursus velit."
+  );
 }

pkgs/native_toolchain_c/test/clinker/testfiles/linker/test2.c

@@ -1,6 +1,12 @@
 #include <stdio.h>
 
-void my_other_func()
+#if _WIN32
+#define FFI_EXPORT __declspec(dllexport)
+#else
+#define FFI_EXPORT
+#endif
+
+FFI_EXPORT void my_other_func()
 {
-  printf("42+1");
+  printf("Hello World");
 }