Compiling the following code with gcj (at least with version 3.4.2 as shipped
with Fedora Core 3) reports no errors or warnings:
class A { class B { int value; } }
class VerifyBug {
A.B b;
VerifyBug() { b = new A.B(); }
static void main(String args[]) {
VerifyBug v = new VerifyBug();
}
}
However when attempting to run the resulting class files with either libgcj or
the Sun JDK 1.5.0 a java.lang.VerifyError is thrown.
Below is the output from a gij invocation:
Exception in thread "main" java.lang.VerifyError: verification failed at PC 10
in VerifyBug:<init>(()V): incompatible type on stack
at _Jv_BytecodeVerifier.verify_fail(byte, int) (/usr/lib/libgcj.so.5.0.0)
at _Jv_BytecodeVerifier.pop_init_ref(_Jv_BytecodeVerifier.type)
(/usr/lib/libgcj.so.5.0.0)
at _Jv_BytecodeVerifier.verify_instructions_0() (/usr/lib/libgcj.so.5.0.0)
at _Jv_VerifyMethod(_Jv_InterpMethod) (/usr/lib/libgcj.so.5.0.0)
at _Jv_PrepareClass(java.lang.Class) (/usr/lib/libgcj.so.5.0.0)
at _Jv_WaitForState(java.lang.Class, int) (/usr/lib/libgcj.so.5.0.0)
at java.lang.VMClassLoader.linkClass0(java.lang.Class)
(/usr/lib/libgcj.so.5.0.0)
at java.lang.VMClassLoader.resolveClass(java.lang.Class)
(/usr/lib/libgcj.so.5.0.0)
at java.lang.Class.initializeClass() (/usr/lib/libgcj.so.5.0.0)
at java.lang.Class.forName(java.lang.String, boolean, java.lang.ClassLoader)
(/usr/lib/libgcj.so.5.0.0)
at java.lang.Class.forName(java.lang.String) (/usr/lib/libgcj.so.5.0.0)
at gnu.gcj.runtime.FirstThread.run() (/usr/lib/libgcj.so.5.0.0)
at _Jv_ThreadRun(java.lang.Thread) (/usr/lib/libgcj.so.5.0.0)
at _Jv_RunMain(java.lang.Class, byte const, int, byte const, boolean)
(/usr/lib/libgcj.so.5.0.0)
at __libc_start_main (/lib/tls/libc-2.3.3.so)
I believe the original Java code is actually wrong, as non-static inner classes
can't be instantiated without an instance of the enclosing class around for some
unfathomable reason. But gcj compiles it without complaint.
(I appologize if this is a duplicate. I searched the list of open and fixed
bugs for Java and didn't anything that seemed to be the same problem, but it
seems possible that the cause is something already in the bug database but not
obvious to me.)
--
Summary: GCJ generates inner class code that fails to verify.
Product: gcc
Version: 3.4.2
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: java
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: gcc-java at esclat dot net
CC: gcc-bugs at gcc dot gnu dot org,java-prs at gcc dot gnu
dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18728
