7903715: Jextract generates duplicate allocator parameters

Reviewed-by: jvernee

Author: mcimadamore

src/main/java/org/openjdk/jextract/impl/HeaderFileBuilder.java

@@ -116,10 +116,6 @@ public void addConstant(Declaration.Constant constantTree) {
     private static List<String> finalizeParameterNames(List<String> parameterNames, boolean needsAllocator, boolean isVarArg) {
         List<String> result = new ArrayList<>();
 
-        if (needsAllocator) {
-            result.add("allocator");
-        }
-
         int i = 0;
         for (; i < parameterNames.size(); i++) {
             String name = parameterNames.get(i);
@@ -133,6 +129,14 @@ private static List<String> finalizeParameterNames(List<String> parameterNames,
             result.add("x" + i);
         }
 
+        if (needsAllocator) {
+            String allocatorName = "allocator";
+            while (result.contains(allocatorName)) {
+                allocatorName = "_" + allocatorName;
+            }
+            result.add(0, allocatorName);
+        }
+
         return result;
     }
 

test/jtreg/generator/mangleParameterNames/TestMangleParameterNames.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2024, 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.
+ *
+ * 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.
+ */
+
+/*
+ * @test
+ * @library /lib
+ * @build testlib.TestUtils
+ * @run main/othervm JtregJextract -t test.jextract.mangle.params parameter_names.h
+ */

test/jtreg/generator/mangleParameterNames/parameter_names.h

@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2024, 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.
+ *
+ * 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.
+ */
+
+#ifdef _WIN64
+#define EXPORT __declspec(dllexport)
+#else
+#define EXPORT
+#endif
+
+struct A { int x; };
+
+EXPORT struct A foo1(int a);
+EXPORT struct A foo2(int allocator);
+EXPORT struct A foo3(int allocator, int _allocator);