Re: [vta/trunk] stabilize Java JNI function types

[Alexandre Oliva <aoliva at redhat dot com>]

On Nov 12, 2007, Andrew Haley <aph-gcc@littlepinkcloud.COM> wrote:

>> * expr.c (build_jni_stub): Use the computed jni func type for
>> variable meth.

> Ok, if you include a comment in the source explaining why you do this.

Here's what I've checked in.

for  gcc/java/ChangeLog
from  Alexandre Oliva  <aoliva@redhat.com>

	* expr.c (build_jni_stub): Use the computed jni func type for
	variable meth.

Index: gcc/java/expr.c
===================================================================
--- gcc/java/expr.c.orig	2007-11-25 02:54:58.000000000 -0200
+++ gcc/java/expr.c	2007-11-25 03:09:27.000000000 -0200
@@ -2651,17 +2651,6 @@ build_jni_stub (tree method)
       TREE_CHAIN (env_var) = res_var;
     }
 
-  meth_var = build_decl (VAR_DECL, get_identifier ("meth"), ptr_type_node);
-  TREE_STATIC (meth_var) = 1;
-  TREE_PUBLIC (meth_var) = 0;
-  DECL_EXTERNAL (meth_var) = 0;
-  DECL_CONTEXT (meth_var) = method;
-  DECL_ARTIFICIAL (meth_var) = 1;
-  DECL_INITIAL (meth_var) = null_pointer_node;
-  TREE_USED (meth_var) = 1;
-  chainon (env_var, meth_var);
-  build_result_decl (method);
-
   method_args = DECL_ARGUMENTS (method);
   block = build_block (env_var, NULL_TREE, method_args, NULL_TREE);
   TREE_SIDE_EFFECTS (block) = 1;
@@ -2725,23 +2714,40 @@ build_jni_stub (tree method)
 
   jni_func_type = build_pointer_type (tem);
 
-  jnifunc = build3 (COND_EXPR, ptr_type_node,
+  /* Use the actual function type, rather than a generic pointer type,
+     such that this decl keeps the actual pointer type from being
+     garbage-collected.  If it is, we end up using canonical types
+     with different uids for equivalent function types, and this in
+     turn causes utf8 identifiers and output order to vary.  */
+  meth_var = build_decl (VAR_DECL, get_identifier ("meth"), jni_func_type);
+  TREE_STATIC (meth_var) = 1;
+  TREE_PUBLIC (meth_var) = 0;
+  DECL_EXTERNAL (meth_var) = 0;
+  DECL_CONTEXT (meth_var) = method;
+  DECL_ARTIFICIAL (meth_var) = 1;
+  DECL_INITIAL (meth_var) = null_pointer_node;
+  TREE_USED (meth_var) = 1;
+  chainon (env_var, meth_var);
+  build_result_decl (method);
+
+  jnifunc = build3 (COND_EXPR, jni_func_type,
 		    build2 (NE_EXPR, boolean_type_node,
 			    meth_var, build_int_cst (TREE_TYPE (meth_var), 0)),
 		    meth_var,
-		    build2 (MODIFY_EXPR, ptr_type_node, meth_var,
-			    build_call_nary (ptr_type_node,
-					     build_address_of
-					       (soft_lookupjnimethod_node),
-					     4,
-					     jniarg0, jniarg1,
-					     jniarg2, jniarg3)));
+		    build2 (MODIFY_EXPR, jni_func_type, meth_var,
+			    build1
+			    (NOP_EXPR, jni_func_type,
+			     build_call_nary (ptr_type_node,
+					      build_address_of
+					      (soft_lookupjnimethod_node),
+					      4,
+					      jniarg0, jniarg1,
+					      jniarg2, jniarg3))));
 
   /* Now we make the actual JNI call via the resulting function
      pointer.    */
   call = build_call_list (TREE_TYPE (TREE_TYPE (method)),
-			  build1 (NOP_EXPR, jni_func_type, jnifunc),
-			  args);
+			  jnifunc, args);
 
   /* If the JNI call returned a result, capture it here.  If we had to
      unwrap JNI object results, we would do that here.  */

-- 
Alexandre Oliva         http://www.lsd.ic.unicamp.br/~oliva/
FSF Latin America Board Member         http://www.fsfla.org/
Red Hat Compiler Engineer   aoliva@{redhat.com, gcc.gnu.org}
Free Software Evangelist  oliva@{lsd.ic.unicamp.br, gnu.org}