7903704: Expose addresses of native functions

Reviewed-by: mcimadamore

Author: JornVernee

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

@@ -156,9 +156,9 @@ private void emitFunctionWrapper(String javaName, String nativeName, boolean nee
                 private static class \{holderClass} {
                     public static final FunctionDescriptor DESC = \{functionDescriptorString(1, decl.type())};
 
-                    public static final MethodHandle HANDLE = Linker.nativeLinker().downcallHandle(
-                                \{runtimeHelperName()}.findOrThrow("\{nativeName}"),
-                                DESC);
+                    public static final MemorySegment ADDR = \{runtimeHelperName()}.findOrThrow("\{nativeName}");
+
+                    public static final MethodHandle HANDLE = Linker.nativeLinker().downcallHandle(ADDR, DESC);
                 }
                 """);
             appendBlankLine();
@@ -175,6 +175,14 @@ private static class \{holderClass} {
                     return \{holderClass}.HANDLE;
                 }
                 """);
+            appendBlankLine();
+            emitDocComment(decl, "Address for:");
+            appendLines(STR."""
+                public static MemorySegment \{javaName}$address() {
+                    return \{holderClass}.ADDR;
+                }
+                """);
+            appendBlankLine();
             emitDocComment(decl);
             appendLines(STR."""
             public static \{retType} \{javaName}(\{paramExprs(declType, finalParamNames, isVarArg)}) {
@@ -224,6 +232,13 @@ public static class \{invokerClassName} {
             decrAlign();
             appendLines(STR."""
 
+                    /**
+                     * {@return the address}
+                     */
+                    public static MemorySegment address() {
+                        return ADDR;
+                    }
+
                     /**
                      * {@return the specialized method handle}
                      */

test/jtreg/TestSplit.java

@@ -31,6 +31,7 @@
 /*
  * @test
  * @library /lib
+ * @build testlib.JextractToolRunner testlib.TestUtils
  * @run testng/othervm -Djextract.decls.per.header=1 TestSplit
  */
 public class TestSplit extends JextractToolRunner {