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Posted to commits@harmony.apache.org by "Nathan Beyer (JIRA)" <ji...@apache.org> on 2008/11/17 03:48:44 UTC
[jira] Created: (HARMONY-6020) Cyclical class dependency causes a
failure not seen in RI
Cyclical class dependency causes a failure not seen in RI
---------------------------------------------------------
Key: HARMONY-6020
URL: https://issues.apache.org/jira/browse/HARMONY-6020
Project: Harmony
Issue Type: Bug
Affects Versions: 5.0M8
Environment: Win Vista 32-bit
Reporter: Nathan Beyer
If two classes have a cyclical dependency, some unexpected results may occur, which are not seen on RI (Sun 6u10).
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Re: [jira] Commented: (HARMONY-6020) [DRLVM] Cyclical class dependency causes a failure not seen in RI
Posted by Xiao-Feng Li <xi...@gmail.com>.
Good catch! And thanks for the test case.
Can we check if the array is null before we check its index?
Thanks,
xiaofeng
On Tue, Dec 30, 2008 at 4:42 PM, Chunrong Lai (JIRA) <ji...@apache.org> wrote:
>
> [ https://issues.apache.org/jira/browse/HARMONY-6020?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12659771#action_12659771 ]
>
> Chunrong Lai commented on HARMONY-6020:
> ---------------------------------------
>
>
> (1) The test case can be further reduced as below:
>
> public class Main {
> public static void main(String[] args) {
> Child c = Parent.createChild();
> System.err.println(c);
> System.err.println(Child.ROOT);
> }
> }
>
> class Parent {
> //private static final Child childCache = new Child();
> private static final Child[] childCache = new Child[5];
>
> public static Child createChild(){
> return childCache[0];
> //return childCache;
> }
> }
>
> class Child {
> public static final Child ROOT = Parent.createChild();
> }
>
> While the exception raises from jitted codes of DRLVM:
>
> 01F00406 mov ecx,dword ptr ds:[34582A0h] //REturn: childCache //Same as Non-Array Case
>
> 01F0040C cmp dword ptr [ecx+8],0 //If ArraySize is 0, throw an exception?
> 01F00410 ht ja 01F0043B //The exception raises from here because the non-inited array has non-assigned length of 0
> //According to JVM spec, we should just return null for non-inited field?
> 01F0043B mov edx,dword ptr [ecx+0Ch] //Return childCache[0]
> 01F0043E mov eax,edx
> 01F00440 mov ebp,dword ptr [esp+0ACh] //We are returning, Same as Non-Array Case
>
> (2) If the cyclic dependence happens not in Array but in a normal object (comment the "Child[] childCache" in Class Parent but uncomment the "Child childCache"), Harmony passes with an exactly same behavior with RI (Child.Root=null, another valid Child object returns in main()). So I do not see harmony has problem for cyclic class loading itself.
> I checked the classloading code and class initialization code and saw it is compatiable with JVM spec.
>
> (3) Anyway there are two valid fixes to me: the first is simply removing the two lines of array length checking binaries (for getStatic). The second is enforcing an array length for the static array field in the very beginning of class initialization. I prefer the first one since I do not see corresponding part in JVM spec for the second approach.
>
> Feedback?
>
>> [DRLVM] Cyclical class dependency causes a failure not seen in RI
>> -----------------------------------------------------------------
>>
>> Key: HARMONY-6020
>> URL: https://issues.apache.org/jira/browse/HARMONY-6020
>> Project: Harmony
>> Issue Type: Bug
>> Components: DRLVM
>> Affects Versions: 5.0M8
>> Environment: Win Vista 32-bit
>> Reporter: Nathan Beyer
>> Assignee: Chunrong Lai
>> Attachments: cycle-project.zip
>>
>>
>> If two classes have a cyclical dependency, some unexpected results may occur, which are not seen on RI (Sun 6u10).
>
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http://xiao-feng.blogspot.com
[jira] Resolved: (HARMONY-6020) [DRLVM] Cyclical class dependency
causes a failure not seen in RI
Posted by "Chunrong Lai (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HARMONY-6020?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Chunrong Lai resolved HARMONY-6020.
-----------------------------------
Resolution: Fixed
Tests are refactored.
> [DRLVM] Cyclical class dependency causes a failure not seen in RI
> -----------------------------------------------------------------
>
> Key: HARMONY-6020
> URL: https://issues.apache.org/jira/browse/HARMONY-6020
> Project: Harmony
> Issue Type: Bug
> Components: DRLVM
> Affects Versions: 5.0M8
> Environment: Win Vista 32-bit
> Reporter: Nathan Beyer
> Assignee: Chunrong Lai
> Fix For: 5.0M9
>
> Attachments: cycle-project.zip
>
>
> If two classes have a cyclical dependency, some unexpected results may occur, which are not seen on RI (Sun 6u10).
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[jira] Commented: (HARMONY-6020) [DRLVM] Cyclical class dependency
causes a failure not seen in RI
Posted by "Nathan Beyer (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HARMONY-6020?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12661414#action_12661414 ]
Nathan Beyer commented on HARMONY-6020:
---------------------------------------
Can we get a regression test added to the DRLVM test suites?
> [DRLVM] Cyclical class dependency causes a failure not seen in RI
> -----------------------------------------------------------------
>
> Key: HARMONY-6020
> URL: https://issues.apache.org/jira/browse/HARMONY-6020
> Project: Harmony
> Issue Type: Bug
> Components: DRLVM
> Affects Versions: 5.0M8
> Environment: Win Vista 32-bit
> Reporter: Nathan Beyer
> Assignee: Chunrong Lai
> Attachments: cycle-project.zip
>
>
> If two classes have a cyclical dependency, some unexpected results may occur, which are not seen on RI (Sun 6u10).
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[jira] Commented: (HARMONY-6020) [DRLVM] Cyclical class dependency
causes a failure not seen in RI
Posted by "Nathan Beyer (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HARMONY-6020?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12661426#action_12661426 ]
Nathan Beyer commented on HARMONY-6020:
---------------------------------------
I've verified that the cycle-project attached now works as expected. We still need to get a regression test added.
> [DRLVM] Cyclical class dependency causes a failure not seen in RI
> -----------------------------------------------------------------
>
> Key: HARMONY-6020
> URL: https://issues.apache.org/jira/browse/HARMONY-6020
> Project: Harmony
> Issue Type: Bug
> Components: DRLVM
> Affects Versions: 5.0M8
> Environment: Win Vista 32-bit
> Reporter: Nathan Beyer
> Assignee: Chunrong Lai
> Attachments: cycle-project.zip
>
>
> If two classes have a cyclical dependency, some unexpected results may occur, which are not seen on RI (Sun 6u10).
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[jira] Commented: (HARMONY-6020) [DRLVM] Cyclical class dependency
causes a failure not seen in RI
Posted by "Chunrong Lai (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HARMONY-6020?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12661035#action_12661035 ]
Chunrong Lai commented on HARMONY-6020:
---------------------------------------
I commit the patch for the exception in array allocation case in r731515. As the result Harmony gets same behavior for the test cases covered in this JIRA as RI. Please verify it.
> [DRLVM] Cyclical class dependency causes a failure not seen in RI
> -----------------------------------------------------------------
>
> Key: HARMONY-6020
> URL: https://issues.apache.org/jira/browse/HARMONY-6020
> Project: Harmony
> Issue Type: Bug
> Components: DRLVM
> Affects Versions: 5.0M8
> Environment: Win Vista 32-bit
> Reporter: Nathan Beyer
> Assignee: Chunrong Lai
> Attachments: cycle-project.zip
>
>
> If two classes have a cyclical dependency, some unexpected results may occur, which are not seen on RI (Sun 6u10).
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[jira] Assigned: (HARMONY-6020) [DRLVM] Cyclical class dependency
causes a failure not seen in RI
Posted by "Chunrong Lai (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HARMONY-6020?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Chunrong Lai reassigned HARMONY-6020:
-------------------------------------
Assignee: Chunrong Lai
> [DRLVM] Cyclical class dependency causes a failure not seen in RI
> -----------------------------------------------------------------
>
> Key: HARMONY-6020
> URL: https://issues.apache.org/jira/browse/HARMONY-6020
> Project: Harmony
> Issue Type: Bug
> Components: DRLVM
> Affects Versions: 5.0M8
> Environment: Win Vista 32-bit
> Reporter: Nathan Beyer
> Assignee: Chunrong Lai
> Attachments: cycle-project.zip
>
>
> If two classes have a cyclical dependency, some unexpected results may occur, which are not seen on RI (Sun 6u10).
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[jira] Commented: (HARMONY-6020) [DRLVM] Cyclical class dependency
causes a failure not seen in RI
Posted by "Chunrong Lai (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HARMONY-6020?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12662008#action_12662008 ]
Chunrong Lai commented on HARMONY-6020:
---------------------------------------
Regression Test added in r732726. Please verify.
> [DRLVM] Cyclical class dependency causes a failure not seen in RI
> -----------------------------------------------------------------
>
> Key: HARMONY-6020
> URL: https://issues.apache.org/jira/browse/HARMONY-6020
> Project: Harmony
> Issue Type: Bug
> Components: DRLVM
> Affects Versions: 5.0M8
> Environment: Win Vista 32-bit
> Reporter: Nathan Beyer
> Assignee: Chunrong Lai
> Fix For: 5.0M9
>
> Attachments: cycle-project.zip
>
>
> If two classes have a cyclical dependency, some unexpected results may occur, which are not seen on RI (Sun 6u10).
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[jira] Resolved: (HARMONY-6020) [DRLVM] Cyclical class dependency
causes a failure not seen in RI
Posted by "Chunrong Lai (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HARMONY-6020?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Chunrong Lai resolved HARMONY-6020.
-----------------------------------
Resolution: Fixed
Fix Version/s: 5.0M9
The commit is verified. So close the issue.
> [DRLVM] Cyclical class dependency causes a failure not seen in RI
> -----------------------------------------------------------------
>
> Key: HARMONY-6020
> URL: https://issues.apache.org/jira/browse/HARMONY-6020
> Project: Harmony
> Issue Type: Bug
> Components: DRLVM
> Affects Versions: 5.0M8
> Environment: Win Vista 32-bit
> Reporter: Nathan Beyer
> Assignee: Chunrong Lai
> Fix For: 5.0M9
>
> Attachments: cycle-project.zip
>
>
> If two classes have a cyclical dependency, some unexpected results may occur, which are not seen on RI (Sun 6u10).
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[jira] Commented: (HARMONY-6020) [DRLVM] Cyclical class dependency
causes a failure not seen in RI
Posted by "Chunrong Lai (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HARMONY-6020?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12659786#action_12659786 ]
Chunrong Lai commented on HARMONY-6020:
---------------------------------------
Thanks for xiaofeng.
Adding NullCheck for the array looks a better approach.
> [DRLVM] Cyclical class dependency causes a failure not seen in RI
> -----------------------------------------------------------------
>
> Key: HARMONY-6020
> URL: https://issues.apache.org/jira/browse/HARMONY-6020
> Project: Harmony
> Issue Type: Bug
> Components: DRLVM
> Affects Versions: 5.0M8
> Environment: Win Vista 32-bit
> Reporter: Nathan Beyer
> Assignee: Chunrong Lai
> Attachments: cycle-project.zip
>
>
> If two classes have a cyclical dependency, some unexpected results may occur, which are not seen on RI (Sun 6u10).
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[jira] Commented: (HARMONY-6020) [DRLVM] Cyclical class dependency
causes a failure not seen in RI
Posted by "Xiao-Feng Li (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HARMONY-6020?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12660536#action_12660536 ]
Xiao-Feng Li commented on HARMONY-6020:
---------------------------------------
When we look at this class definition:
class Parent {
private static final Child[] childCache = new Child[5];
public static Child createChild(){
return childCache[0];
}
}
It is clear that, the semantics expectation is, childCache should be assigned a value when class Parent is ready (i.e., initialized). And this value should be assigned to childCache before anybody can access any Parent's method, e.g., createChild(). This is the semantics expectation. I guess we need to ensure this semantics.
Can we simply let this Child clinit() execute in this way: When it tries to call Parent.createChild() and finds Parent is under initialization, it simply returns null to ROOT without really invoking createChild().
According to the JVM spec 2.17.4, it requires any static method invocation must happen after the class is "initialized." The problem is, how to deal with the situation when a static method is invoked when the owning class is under initialization.
Thanks,
xiaofeng
> [DRLVM] Cyclical class dependency causes a failure not seen in RI
> -----------------------------------------------------------------
>
> Key: HARMONY-6020
> URL: https://issues.apache.org/jira/browse/HARMONY-6020
> Project: Harmony
> Issue Type: Bug
> Components: DRLVM
> Affects Versions: 5.0M8
> Environment: Win Vista 32-bit
> Reporter: Nathan Beyer
> Assignee: Chunrong Lai
> Attachments: cycle-project.zip
>
>
> If two classes have a cyclical dependency, some unexpected results may occur, which are not seen on RI (Sun 6u10).
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[jira] Reopened: (HARMONY-6020) [DRLVM] Cyclical class dependency
causes a failure not seen in RI
Posted by "Nathan Beyer (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HARMONY-6020?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Nathan Beyer reopened HARMONY-6020:
-----------------------------------
Reopening - we need a regression test.
> [DRLVM] Cyclical class dependency causes a failure not seen in RI
> -----------------------------------------------------------------
>
> Key: HARMONY-6020
> URL: https://issues.apache.org/jira/browse/HARMONY-6020
> Project: Harmony
> Issue Type: Bug
> Components: DRLVM
> Affects Versions: 5.0M8
> Environment: Win Vista 32-bit
> Reporter: Nathan Beyer
> Assignee: Chunrong Lai
> Fix For: 5.0M9
>
> Attachments: cycle-project.zip
>
>
> If two classes have a cyclical dependency, some unexpected results may occur, which are not seen on RI (Sun 6u10).
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[jira] Commented: (HARMONY-6020) [DRLVM] Cyclical class dependency
causes a failure not seen in RI
Posted by "Nathan Beyer (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HARMONY-6020?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12662233#action_12662233 ]
Nathan Beyer commented on HARMONY-6020:
---------------------------------------
I know that putting more than one class in a file is allowed, but it's an ugly and confusing practice. Please refactor the classes into their own files.
> [DRLVM] Cyclical class dependency causes a failure not seen in RI
> -----------------------------------------------------------------
>
> Key: HARMONY-6020
> URL: https://issues.apache.org/jira/browse/HARMONY-6020
> Project: Harmony
> Issue Type: Bug
> Components: DRLVM
> Affects Versions: 5.0M8
> Environment: Win Vista 32-bit
> Reporter: Nathan Beyer
> Assignee: Chunrong Lai
> Fix For: 5.0M9
>
> Attachments: cycle-project.zip
>
>
> If two classes have a cyclical dependency, some unexpected results may occur, which are not seen on RI (Sun 6u10).
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[jira] Updated: (HARMONY-6020) Cyclical class dependency causes a
failure not seen in RI
Posted by "Nathan Beyer (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HARMONY-6020?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Nathan Beyer updated HARMONY-6020:
----------------------------------
Attachment: cycle-project.zip
cycle-project.zip
This file contains an Eclipse project export with a few classes that present a contrived example. If the 'cycle.Main' class is run on an RI, the toString value of an object is printed. On M7 and current trunk build of Harmony (DRLVM + Classlib), a NullPointException with a cause of ExceptionInInitializer.
> Cyclical class dependency causes a failure not seen in RI
> ---------------------------------------------------------
>
> Key: HARMONY-6020
> URL: https://issues.apache.org/jira/browse/HARMONY-6020
> Project: Harmony
> Issue Type: Bug
> Affects Versions: 5.0M8
> Environment: Win Vista 32-bit
> Reporter: Nathan Beyer
> Attachments: cycle-project.zip
>
>
> If two classes have a cyclical dependency, some unexpected results may occur, which are not seen on RI (Sun 6u10).
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[jira] Commented: (HARMONY-6020) [DRLVM] Cyclical class dependency
causes a failure not seen in RI
Posted by "Chunrong Lai (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HARMONY-6020?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12659771#action_12659771 ]
Chunrong Lai commented on HARMONY-6020:
---------------------------------------
(1) The test case can be further reduced as below:
public class Main {
public static void main(String[] args) {
Child c = Parent.createChild();
System.err.println(c);
System.err.println(Child.ROOT);
}
}
class Parent {
//private static final Child childCache = new Child();
private static final Child[] childCache = new Child[5];
public static Child createChild(){
return childCache[0];
//return childCache;
}
}
class Child {
public static final Child ROOT = Parent.createChild();
}
While the exception raises from jitted codes of DRLVM:
01F00406 mov ecx,dword ptr ds:[34582A0h] //REturn: childCache //Same as Non-Array Case
01F0040C cmp dword ptr [ecx+8],0 //If ArraySize is 0, throw an exception?
01F00410 ht ja 01F0043B //The exception raises from here because the non-inited array has non-assigned length of 0
//According to JVM spec, we should just return null for non-inited field?
01F0043B mov edx,dword ptr [ecx+0Ch] //Return childCache[0]
01F0043E mov eax,edx
01F00440 mov ebp,dword ptr [esp+0ACh] //We are returning, Same as Non-Array Case
(2) If the cyclic dependence happens not in Array but in a normal object (comment the "Child[] childCache" in Class Parent but uncomment the "Child childCache"), Harmony passes with an exactly same behavior with RI (Child.Root=null, another valid Child object returns in main()). So I do not see harmony has problem for cyclic class loading itself.
I checked the classloading code and class initialization code and saw it is compatiable with JVM spec.
(3) Anyway there are two valid fixes to me: the first is simply removing the two lines of array length checking binaries (for getStatic). The second is enforcing an array length for the static array field in the very beginning of class initialization. I prefer the first one since I do not see corresponding part in JVM spec for the second approach.
Feedback?
> [DRLVM] Cyclical class dependency causes a failure not seen in RI
> -----------------------------------------------------------------
>
> Key: HARMONY-6020
> URL: https://issues.apache.org/jira/browse/HARMONY-6020
> Project: Harmony
> Issue Type: Bug
> Components: DRLVM
> Affects Versions: 5.0M8
> Environment: Win Vista 32-bit
> Reporter: Nathan Beyer
> Assignee: Chunrong Lai
> Attachments: cycle-project.zip
>
>
> If two classes have a cyclical dependency, some unexpected results may occur, which are not seen on RI (Sun 6u10).
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[jira] Updated: (HARMONY-6020) [DRLVM] Cyclical class dependency
causes a failure not seen in RI
Posted by "Tim Ellison (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HARMONY-6020?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Tim Ellison updated HARMONY-6020:
---------------------------------
Component/s: DRLVM
Summary: [DRLVM] Cyclical class dependency causes a failure not seen in RI (was: Cyclical class dependency causes a failure not seen in RI)
Redirecting to the DRLVM since this works with Harmony class libraries and the IBM VME
Stack dump on DRLVM is
C:\temp>\harmony-jdk-713673\jre\bin\java -showversion -jar cycle.jar
Apache Harmony Launcher : (c) Copyright 1991, 2008 The Apache Software Foundation or its licensors, as applicable.
java version "1.5.0"
pre-alpha : not complete or compatible
svn = r713673, (Nov 13 2008), Windows/ia32/msvc 1310, release build
http://harmony.apache.org
Uncaught exception in main:
java.lang.reflect.InvocationTargetException
at java.lang.reflect.VMReflection.invokeMethod(VMReflection.java)
at java.lang.reflect.Method.invoke(Method.java:317)
at org.apache.harmony.vm.JarRunner.main(JarRunner.java:89)
Caused by: java.lang.ExceptionInInitializerError
at cycle.Parent.<clinit>(Parent.java:5)
at cycle.Main.main(Main.java:6)
at java.lang.reflect.VMReflection.invokeMethod(VMReflection.java)
... 2 more
Caused by: java.lang.NullPointerException
at cycle.Parent.getCachedChild(Parent.java:8)
at cycle.Parent.createChild(Parent.java:19)
at cycle.Child.<clinit>(Child.java:4)
at cycle.Parent.<clinit>(Parent.java:5)
... 4 more
> [DRLVM] Cyclical class dependency causes a failure not seen in RI
> -----------------------------------------------------------------
>
> Key: HARMONY-6020
> URL: https://issues.apache.org/jira/browse/HARMONY-6020
> Project: Harmony
> Issue Type: Bug
> Components: DRLVM
> Affects Versions: 5.0M8
> Environment: Win Vista 32-bit
> Reporter: Nathan Beyer
> Attachments: cycle-project.zip
>
>
> If two classes have a cyclical dependency, some unexpected results may occur, which are not seen on RI (Sun 6u10).
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