------- Comment #1 from pinskia at gmail dot com 2009-01-13 19:22 -------
Subject: Re: New: gcj emitting incorrect code
On Jan 13, 2009, at 8:03 AM, "tschwinge at gcc dot gnu dot org"
<gcc-bugzi...@gcc.gnu.org
> wrote:
> I originally found this problem when trying to compile a Java
> package written
> by the Universität Stuttgart's institute IKR. I was using Debian's
> gcj
> package, version 4.3.2-2, but can likewise reproduce this using SVN
> trunk, as
> well as Debian's 4.2.4-4 package.
>
> I completely reduced the test case to the following:
>
> public class Bug_Class
> {
> }
>
> public interface Bug_Interface
> {
> }
>
> public class Bug
> {
> public <X extends Bug_Class & Bug_Interface> Bug(X x)
> {
> set(x);
> }
>
> public void set(Bug_Interface x)
> {
> }
> }
>
> Directly compiling this will fail as follows:
>
> $ ~/GCC/trunk.build.64.install/bin/gcj -c Bug.java
> Bug.java: In class 'Bug':
> Bug.java: In constructor '(Bug_Class)':
> In file included from <built-in>:3:
> Bug.java:3: error: verification failed at PC=9: incompatible type
> on stack
>
> gcj is able to emit a class file, but that one is considered non-
> verifying by
> the BCEL verifier:
This sounds like a bug in the eclispe source to bytecode compiler
which gcj uses now.
>
>
> [...]
> Pass 3b, method number 0 ['public void <init>(Bug_Class arg1)
> [Signature(<E:LBug_Class;:LBug_Interface;>(TE;)V)]']:
> VERIFIED_REJECTED
> Constraint violated in method 'public void <init>(Bug_Class arg1)
> [Signature(<E:LBug_Class;:LBug_Interface;>(TE;)V)]':
> Instruction INVOKEVIRTUAL constraint violated: Expecting a
> 'Bug_Interface'
> but found a 'Bug_Class' on the stack (which is not assignment
> compatible).
> InstructionHandle: 6: invokevirtual[182](3) 13
> [...]
>
> What Sun's javac does differently (as per class-file disassembly
> inspection) is
> emitting a checkcast against class Bug_Interface before calling
> invokevirtual.
>
>
> --
> Summary: gcj emitting incorrect code
> Product: gcc
> Version: 4.3.2
> Status: UNCONFIRMED
> Severity: normal
> Priority: P3
> Component: java
> AssignedTo: unassigned at gcc dot gnu dot org
> ReportedBy: tschwinge at gcc dot gnu dot org
>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38827
>
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38827
