[GR-71047] Fix encoding mismatch when handling argv on Windows.

substratevm/src/com.oracle.svm.core.windows/src/com/oracle/svm/core/windows/WindowsJavaMainWrapperArgsSupport.java

@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2025, 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package com.oracle.svm.core.windows;
+
+import static com.oracle.svm.core.windows.headers.StringAPISet.CP_ACP;
+import static com.oracle.svm.core.windows.headers.StringAPISet.MultiByteToWideChar;
+
+import org.graalvm.nativeimage.c.type.CCharPointer;
+
+import com.oracle.svm.core.JavaMainWrapper;
+import com.oracle.svm.core.feature.AutomaticallyRegisteredImageSingleton;
+import com.oracle.svm.core.handles.PrimitiveArrayView;
+import com.oracle.svm.core.log.StringBuilderLog;
+import com.oracle.svm.core.util.UnsignedUtils;
+import com.oracle.svm.core.util.VMError;
+import com.oracle.svm.core.windows.headers.WinBase;
+import com.oracle.svm.core.windows.headers.WindowsLibC;
+
+import jdk.graal.compiler.word.Word;
+
+@AutomaticallyRegisteredImageSingleton
+class WindowsJavaMainWrapperArgsSupport extends JavaMainWrapper.ArgsSupport {
+    @Override
+    protected String toJavaArg(CCharPointer rawArg) {
+        /*
+         * On Windows, wide-character strings are UTF-16LE, matching Java char[]. So we convert ANSI
+         * bytes directly into a Java char[] (excluding the trailing NUL) and construct the String.
+         */
+        int rawLen = UnsignedUtils.safeToInt(WindowsLibC.strlen(rawArg)); // excludes trailing NUL
+        if (rawLen == 0) {
+            return ""; // MultiByteToWideChar would fail here
+        }
+        int wcLen = checkResult(MultiByteToWideChar(CP_ACP(), 0, rawArg, rawLen, Word.nullPointer(), 0));
+        char[] wcArg = new char[wcLen];
+        try (var wcBuf = PrimitiveArrayView.createForReadingAndWriting(wcArg)) {
+            checkResult(MultiByteToWideChar(CP_ACP(), 0, rawArg, rawLen, wcBuf.addressOfArrayElement(0), wcLen));
+        }
+        return new String(wcArg);
+    }
+
+    private static int checkResult(int result) {
+        if (result == 0) {
+            var log = new StringBuilderLog();
+            log.string("MultiByteToWideChar failed with error ").hex(WinBase.GetLastError());
+            throw VMError.shouldNotReachHere(log.getResult());
+        }
+        return result;
+    }
+}

substratevm/src/com.oracle.svm.core.windows/src/com/oracle/svm/core/windows/headers/StringAPISet.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2025, 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package com.oracle.svm.core.windows.headers;
+
+import org.graalvm.nativeimage.c.CContext;
+import org.graalvm.nativeimage.c.constant.CConstant;
+import org.graalvm.nativeimage.c.function.CFunction;
+import org.graalvm.nativeimage.c.type.CCharPointer;
+
+import com.oracle.svm.core.windows.headers.WindowsLibC.WCharPointer;
+
+// Checkstyle: stop
+
+/**
+ * Definitions for Windows stringapiset.h
+ */
+@CContext(WindowsDirectives.class)
+public class StringAPISet {
+
+    /** The system-wide Windows ANSI code page. */
+    @CConstant
+    public static native int CP_ACP();
+
+    /** Maps a character string to a UTF-16 (wide character) string. */
+    @CFunction(transition = CFunction.Transition.NO_TRANSITION)
+    public static native int MultiByteToWideChar(int CodePage, int dwFlags, CCharPointer lpMultiByteStr, int cbMultiByte, WCharPointer lpWideCharStr, int cchWideChar);
+}

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/JavaMainWrapper.java

@@ -65,6 +65,7 @@
 import com.oracle.svm.core.c.function.CEntryPointOptions.NoEpilogue;
 import com.oracle.svm.core.c.function.CEntryPointOptions.NoPrologue;
 import com.oracle.svm.core.c.function.CEntryPointSetup;
+import com.oracle.svm.core.feature.AutomaticallyRegisteredImageSingleton;
 import com.oracle.svm.core.graal.snippets.CEntryPointSnippets;
 import com.oracle.svm.core.jdk.InternalVMMethod;
 import com.oracle.svm.core.jdk.RuntimeSupport;
@@ -150,7 +151,7 @@ public String getJavaCommand() {
         public List<String> getInputArguments() {
             CEntryPointCreateIsolateParameters args = MAIN_ISOLATE_PARAMETERS.get();
             if (args.getArgv().isNonNull() && args.getArgc() > 0) {
-                String[] unmodifiedArgs = SubstrateUtil.convertCToJavaArgs(args.getArgc(), args.getArgv());
+                String[] unmodifiedArgs = ArgsSupport.convertCToJavaArgs(args.getArgc(), args.getArgv());
                 List<String> inputArgs = new ArrayList<>(Arrays.asList(unmodifiedArgs));
 
                 if (mainArgs != null) {
@@ -479,4 +480,34 @@ static void enter(Isolate isolate) {
             }
         }
     }
+
+    /** Support for platform-specific conversion of the command line to Java main arguments. */
+    @AutomaticallyRegisteredImageSingleton(ArgsSupport.class)
+    public static class ArgsSupport {
+        private static ArgsSupport singleton() {
+            return ImageSingletons.lookup(ArgsSupport.class);
+        }
+
+        /**
+         * Convert C-style to Java-style command line arguments. The first C-style argument, which
+         * is always the executable file name, is ignored.
+         *
+         * @param argc the number of arguments in the {@code argv} array.
+         * @param argv a C {@code char**}.
+         *
+         * @return the command line argument strings in a Java string array.
+         */
+        public static String[] convertCToJavaArgs(int argc, CCharPointerPointer argv) {
+            String[] args = new String[argc - 1];
+            for (int i = 1; i < argc; ++i) {
+                args[i - 1] = singleton().toJavaArg(argv.read(i));
+            }
+            return args;
+        }
+
+        /** Converts a single argv element to a Java string. */
+        protected String toJavaArg(CCharPointer rawArg) {
+            return CTypeConversion.toJavaString(rawArg);
+        }
+    }
 }

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/SubstrateUtil.java

@@ -40,8 +40,6 @@
 import org.graalvm.nativeimage.Platform;
 import org.graalvm.nativeimage.Platforms;
 import org.graalvm.nativeimage.c.type.CCharPointer;
-import org.graalvm.nativeimage.c.type.CCharPointerPointer;
-import org.graalvm.nativeimage.c.type.CTypeConversion;
 import org.graalvm.word.Pointer;
 import org.graalvm.word.UnsignedWord;
 
@@ -152,23 +150,6 @@ public static FileDescriptor getFileDescriptor(FileOutputStream out) {
         return SubstrateUtil.cast(out, Target_java_io_FileOutputStream.class).fd;
     }
 
-    /**
-     * Convert C-style to Java-style command line arguments. The first C-style argument, which is
-     * always the executable file name, is ignored.
-     *
-     * @param argc the number of arguments in the {@code argv} array.
-     * @param argv a C {@code char**}.
-     *
-     * @return the command line argument strings in a Java string array.
-     */
-    public static String[] convertCToJavaArgs(int argc, CCharPointerPointer argv) {
-        String[] args = new String[argc - 1];
-        for (int i = 1; i < argc; ++i) {
-            args[i - 1] = CTypeConversion.toJavaString(argv.read(i));
-        }
-        return args;
-    }
-
     /**
      * Returns the length of a C {@code char*} string.
      */

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/graal/snippets/CEntryPointSnippets.java

@@ -35,6 +35,7 @@
 
 import java.util.Map;
 
+import com.oracle.svm.core.JavaMainWrapper;
 import org.graalvm.nativeimage.CurrentIsolate;
 import org.graalvm.nativeimage.ImageSingletons;
 import org.graalvm.nativeimage.Isolate;
@@ -60,7 +61,6 @@
 import com.oracle.svm.core.RuntimeAssertionsSupport;
 import com.oracle.svm.core.SubstrateDiagnostics;
 import com.oracle.svm.core.SubstrateOptions;
-import com.oracle.svm.core.SubstrateUtil;
 import com.oracle.svm.core.Uninterruptible;
 import com.oracle.svm.core.UnmanagedMemoryUtil;
 import com.oracle.svm.core.c.CGlobalData;
@@ -452,7 +452,7 @@ private static int initializeIsolateInterruptibly1(CEntryPointCreateIsolateParam
                 exitWhenArgumentParsingFails = parameters.getExitWhenArgumentParsingFails();
             }
 
-            String[] args = SubstrateUtil.convertCToJavaArgs(parameters.getArgc(), parameters.getArgv());
+            String[] args = JavaMainWrapper.ArgsSupport.convertCToJavaArgs(parameters.getArgc(), parameters.getArgv());
             try {
                 args = RuntimeOptionParser.parseAndConsumeAllOptions(args, ignoreUnrecognized);
             } catch (IllegalArgumentException e) {