Re: [PATCH] Fix PR java/17265

[Bryce McKinlay <mckinlay at redhat dot com>]

Bryce McKinlay wrote:

> Eric Botcazou wrote:
>
> > Hi,
> >
> > This patch reverts
> >
> > 2004-08-18  Bryce McKinlay  <mckinlay@redhat.com>
> >
> >        * class.c (make_local_function_alias): New function. Create local
> >        alias for public method DECL.
> >        (make_method_value): Use make_local_function_alias.
> >
> > which breaks the GCJ compiler with non-GNU assemblers.  The problem 
> > is that it instructs the compiler to create local aliases of external 
> > functions.
> >  
>
> Eric,
>
> Could you try this version of the patch and see if it fixes 17265 for 
> you? This one will not try to emit an alias for an external function 
> (which I agree is useless). Making an alias for a local function 
> however is not useless - we need this for accurate stack traces and 
> security checks, so I'd like to get this patch back in.
>
> Bryce

The patch...


2004-10-22  Bryce McKinlay  <mckinlay@redhat.com>

	PR java/17265
	* class.c: Reinstate 2004-08-18 patch. 
	(make_local_function_alias): Don't create an alias for extern (native)
	functions.

Index: class.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/java/class.c,v
retrieving revision 1.212
diff -u -r1.212 class.c
--- class.c	22 Oct 2004 14:30:37 -0000	1.212
+++ class.c	22 Oct 2004 18:28:41 -0000
@@ -1198,6 +1198,53 @@
   abort ();
 }
 
+static GTY (()) int alias_labelno = 0;
+
+/* Create a private alias for METHOD. Using this alias instead of the method
+   decl ensures that ncode entries in the method table point to the real function 
+   at runtime, not a PLT entry.  */
+
+static tree
+make_local_function_alias (tree method)
+{
+#ifdef ASM_OUTPUT_DEF
+  tree alias;
+  
+  const char *method_name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (method));
+  char *name = alloca (strlen (method_name) + 2);
+  char *buf = alloca (strlen (method_name) + 128);
+
+  /* Only create aliases for local functions.  */
+  if (DECL_EXTERNAL (method))
+    return method;
+    
+  /* Prefix method_name with 'L' for the alias label.  */
+  *name = 'L';
+  strcpy (name + 1, method_name);
+
+  ASM_GENERATE_INTERNAL_LABEL (buf, name, alias_labelno++);  
+  alias = build_decl (FUNCTION_DECL, get_identifier (buf),
+		      TREE_TYPE (method));
+  DECL_CONTEXT (alias) = NULL;
+  TREE_READONLY (alias) = TREE_READONLY (method);
+  TREE_THIS_VOLATILE (alias) = TREE_THIS_VOLATILE (method);
+  TREE_PUBLIC (alias) = 0;
+  DECL_EXTERNAL (alias) = 0;
+  DECL_ARTIFICIAL (alias) = 1;
+  DECL_INLINE (alias) = 0;
+  DECL_INITIAL (alias) = error_mark_node;
+  TREE_ADDRESSABLE (alias) = 1;
+  TREE_USED (alias) = 1;
+  SET_DECL_ASSEMBLER_NAME (alias, DECL_NAME (alias));
+  TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (alias)) = 1;
+  if (!flag_syntax_only)
+    assemble_alias (alias, DECL_ASSEMBLER_NAME (method));
+  return alias;
+#else
+  return method;
+#endif
+}
+
 /** Make reflection data (_Jv_Field) for field FDECL. */
 
 static tree
@@ -1269,7 +1316,8 @@
 
   code = null_pointer_node;
   if (DECL_RTL_SET_P (mdecl))
-    code = build1 (ADDR_EXPR, nativecode_ptr_type_node, mdecl);
+    code = build1 (ADDR_EXPR, nativecode_ptr_type_node, 
+		   make_local_function_alias (mdecl));
   START_RECORD_CONSTRUCTOR (minit, method_type_node);
   PUSH_FIELD_VALUE (minit, "name",
 		    build_utf8_ref (DECL_CONSTRUCTOR_P (mdecl) ?