Fixed possible VMErrors in runtime code dumping.

Author: matteoldani

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

@@ -520,4 +520,18 @@ public static Class<?> toUnboxedClassWithDefault(Class<?> clazz, Class<?> defaul
             return defaultClass;
         }
     }
+
+    /** Sanitizes a name to be used in a file name. Special characters are replaced with '_'. */
+    public static String sanitizeForFileName(String name) {
+        StringBuilder buf = new StringBuilder(name.length());
+        for (int i = 0; i < name.length(); i++) {
+            char c = name.charAt(i);
+            if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '.' || (c >= '0' && c <= '9')) {
+                buf.append(c);
+            } else {
+                buf.append('_');
+            }
+        }
+        return buf.toString();
+    }
 }

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/code/RuntimeCodeCache.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 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
@@ -65,8 +65,6 @@
 import jdk.graal.compiler.options.OptionType;
 import jdk.graal.compiler.word.Word;
 
-import java.text.SimpleDateFormat;
-
 public class RuntimeCodeCache {
 
     public static class Options {
@@ -174,11 +172,18 @@ private static RawFileOperationSupport getFileSupport() {
     }
 
     private static void dumpMethod(CodeInfo info) {
-        String methodName = CodeInfoAccess.getName(info);
-        int tier = CodeInfoAccess.getTier(info);
-        String date = new SimpleDateFormat("yyyy.MM.dd.HH.mm.ss").format(new java.util.Date());
         String tmpDirPath = getFileSupport().getTempDirectory();
-        String filePath = tmpDirPath + "/" + date + "_" + methodName + "_" + tier + ".bin";
+        String prefix = System.nanoTime() + "_";
+        String methodName = SubstrateUtil.sanitizeForFileName(CodeInfoAccess.getName(info));
+        String suffix = "_" + CodeInfoAccess.getTier(info) + ".bin";
+
+        // Check that the file name size does not exceed the 255 chars
+        int maxMethodNameSize = 255 - prefix.length() - suffix.length();
+        if (methodName.length() > maxMethodNameSize) {
+            methodName = methodName.substring(maxMethodNameSize);
+        }
+
+        String filePath = tmpDirPath + "/" + prefix + methodName + suffix;
 
         RawFileOperationSupport.RawFileDescriptor fd = getFileSupport().create(filePath, CREATE_OR_REPLACE, WRITE);
         if (!getFileSupport().isValid(fd)) {