JNI in GCJ 3.2 for Win32

[Ranjit Mathew]

Wow! Thanks for that detailed explanation!

I tried it out for the case of just adding the extra
argument size, but it failed with an "internal error:
Segmentation fault" :-(

I'll try it afresh tomorrow.

In any case, here's my attempted changes for the native
stubs part (GCJ 3.2) so far:
-------------------------- 8< -----------------------------
--- decl.c.orig	2002-11-11 03:02:05.000000000 +0530
+++ decl.c	2002-11-11 03:40:08.000000000 +0530
@@ -850,5 +850,6 @@
    t = tree_cons (NULL_TREE, object_ptr_type_node,
  		 tree_cons (NULL_TREE, ptr_type_node,
-			    tree_cons (NULL_TREE, ptr_type_node, endlink)));
+			    tree_cons (NULL_TREE, ptr_type_node,
+			               tree_cons (NULL_TREE, unsigned_short_type_node, 
endlink))));
    soft_lookupjnimethod_node
      = builtin_function ("_Jv_LookupJNIMethod",
--- expr.c.orig	2002-11-11 03:02:00.000000000 +0530
+++ expr.c	2002-11-11 05:43:36.000000000 +0530
@@ -2187,4 +2187,6 @@
    tree meth_var;

+  unsigned short args_size = 0;
+
    tree klass = DECL_CONTEXT (method);
    int from_class = ! CLASS_FROM_SOURCE_P (klass);
@@ -2248,5 +2250,8 @@
    args = NULL_TREE;
    for (tem = method_args; tem != NULL_TREE; tem = TREE_CHAIN (tem))
-    args = tree_cons (NULL_TREE, tem, args);
+    {
+      args_size += size_in_bytes (TREE_TYPE(tem));
+      args = tree_cons (NULL_TREE, tem, args);
+    }
    args = nreverse (args);
    arg_types = TYPE_ARG_TYPES (TREE_TYPE (method));
@@ -2257,4 +2262,5 @@
    if (METHOD_STATIC (method))
      {
+      args_size += size_in_bytes (TREE_TYPE(klass));
        args = tree_cons (NULL_TREE, klass, args);
        arg_types = tree_cons (NULL_TREE, object_ptr_type_node, arg_types);
@@ -2262,4 +2268,5 @@

    /* The JNIEnv structure is the first argument to the JNI function.  */
+  args_size += size_in_bytes (TREE_TYPE(env_var));
    args = tree_cons (NULL_TREE, env_var, args);
    arg_types = tree_cons (NULL_TREE, ptr_type_node, arg_types);
@@ -2268,18 +2275,24 @@
       function pointer.  _Jv_LookupJNIMethod will throw the appropriate
       exception if this function is not found at runtime.  */
+  tem = build_tree_list (NULL_TREE, build_int_2 (args_size, 0));
    method_sig = build_java_signature (TREE_TYPE (method));
-  lookup_arg =
-    build_tree_list (NULL_TREE,
-		     build_utf8_ref (unmangle_classname
-				     (IDENTIFIER_POINTER (method_sig),
-				      IDENTIFIER_LENGTH (method_sig))));
+  lookup_arg
+    = tree_cons (
+        NULL_TREE,
+        build_utf8_ref (unmangle_classname (
+	                  IDENTIFIER_POINTER (method_sig),
+			  IDENTIFIER_LENGTH (method_sig))),
+        tem);
    tem = DECL_NAME (method);
    lookup_arg
      = tree_cons (NULL_TREE, klass,
  		 tree_cons (NULL_TREE, build_utf8_ref (tem), lookup_arg));
-
-  jni_func_type
-    = build_pointer_type (build_function_type (TREE_TYPE (TREE_TYPE 
(method)),
-					       arg_types));
+
+  tem = build_function_type (TREE_TYPE (TREE_TYPE (method)), arg_types);
+#if defined (__MINGW32__) || defined (__CYGWIN__)
+  /* JNI methods on Win32 are invoked using the stdcall convention */
+  tem = build_type_attribute_variant (tem, get_identifier ("stdcall"));
+#endif
+  jni_func_type = build_pointer_type (tem);

    jnifunc = build (COND_EXPR, ptr_type_node,
-------------------------- 8< -----------------------------