Re: GCJ adding extra underscore to enum value symbol name?

[Andrew Haley <aph at gcc dot gnu dot org>]

Fred Pendleton writes:
 > I'm running into a problem compiling a Java enum using GCJ 4.3.0 20070323, with the 
 > ecj front end. It appears as though GCJ is inserting an extra underscore character 
 > into the symbol name of certain Java enum values when compiling to an object file.
 > 
 > Take this example Java enum:
 > ////////////////////////////
 > public enum TestEnum
 > {
 >   TEST,
 >   PREREQUISITE,
 >   TEST_PREREQUISITE,
 >   TEST_TEST_PREREQUISITE,
 >   TEST_TEST_TEST_TEST
 > }
 > ////////////////////////////
 > 
 > And this C++ code that uses the enum value TestEnum.TEST_TEST_PREREQUISITE:
 > ////////////////////////////
 > #include "TestEnum.h"
 > 
 > TestEnum* e = TestEnum::TEST_TEST_PREREQUISITE;
 > ////////////////////////////
 > 
 > After compiling the Java enum to an object file, these are the symbol names that nm 
 > emits:
 > _ZN8TestEnum4TESTE
 > _ZN8TestEnum12PREREQUISITEE
 > _ZN8TestEnum17TEST_PREREQUISITEE
 > _ZN8TestEnum23TEST_TEST_PREREQU_ISITEE
 > _ZN8TestEnum19TEST_TEST_TEST_TESTE
 > 
 > Notice that the second last symbol name has an extra underscore between the U and the 
 > I, and that this underscore does not exist in the Java enum value's name. This 
 > appears to be causing problems when linking via CNI to C++ code that does not expect 
 > that underscore to be present. According to nm run on the object file for the above 
 > C++ code, the _ZN8TestEnum22TEST_TEST_PREREQUISITEE symbol is expected.
 > 
 > Can anyone shed some light onto why this is happening? Is it a bug in GCJ?

You've hit a bug in append_unicode_mangled_name().  The fix might be
as simple as this:

Index: mangle_name.c
===================================================================
--- mangle_name.c	(revision 123084)
+++ mangle_name.c	(working copy)
@@ -84,7 +84,10 @@
       int ch = UTF8_GET(ptr, limit);
 
       if ((ISALNUM (ch) && ch != 'U') || ch == '$')
-	obstack_1grow (mangle_obstack, ch);
+	{
+	  obstack_1grow (mangle_obstack, ch);
+	  uuU = 0;
+	}
       /* Everything else needs encoding */
       else
 	{

Let us know if this works.

Andrew.