[
https://issues.apache.org/jira/browse/BCEL-41?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Emmanuel Bourg updated BCEL-41:
-------------------------------
Component/s: (was: Main)
Verifier
Description:
Consider the class
{code}
public class Demo
{
public static void main(String[] args)
{
Object[] objs = new Integer[1];
objs[0] = o();
}
private static Object o()
{
return null;
}
}
{code}
It compiles fine, and
{code}java -verify Demo{code}
executes without errors. However,
java org.apache.bcel.verifier.Verifier Demo
complains:
{code}
Pass 3b, method number 1 ['public static void main(String[] arg0)']:
VERIFIED_REJECTED
Constraint violated in method 'public static void main(String[] arg0)':
Instruction AASTORE constraint violated: The type of 'value'
('java.lang.Object') is not assignment
compatible to the components of the array 'arrayref' refers to.
('java.lang.Integer')
{code}
etc.
The problem is that while the vmspec2 says "The type of every value stored into
an array of type reference by an aastore instruction must be assignment
compatible (§2.6.7) with the component type of the array", the class file
doesn't contain information on the compile-time component type of the array. I
suspect the native verifier does nothing about this requirement, leaving the VM
to throw an ArrayStoreException if problems arise.
Enver Haase asked me to mention in this report that while the error message
says "assignment compatible to" and the vmspec2 says "assignment compatible
with", it's not a case of doing the check the wrong way round.
was:
Consider the class
public class Demo
{
public static void main(String[] args)
{
Object[] objs = new Integer[1];
objs[0] = o();
}
private static Object o()
{
return null;
}
}
It compiles fine, and
java -verify Demo
executes without errors. However,
java org.apache.bcel.verifier.Verifier Demo
complains:
Pass 3b, method number 1 ['public static void main(String[] arg0)']:
VERIFIED_REJECTED
Constraint violated in method 'public static void main(String[] arg0)':
Instruction AASTORE constraint violated: The type of 'value'
('java.lang.Object') is not assignment
compatible to the components of the array 'arrayref' refers to.
('java.lang.Integer')
etc.
The problem is that while the vmspec2 says "The type of every value stored into
an array of type
reference by an aastore instruction must be assignment compatible (§2.6.7) with
the component
type of the array", the class file doesn't contain information on the
compile-time component type
of the array. I suspect the native verifier does nothing about this
requirement, leaving the VM to
throw an ArrayStoreException if problems arise.
Enver Haase asked me to mention in this report that while the error message
says "assignment
compatible to" and the vmspec2 says "assignment compatible with", it's not a
case of doing the
check the wrong way round.
Priority: Major
Environment: (was: Operating System: All
Platform: All)
Affects Version/s: (was: unspecified)
Priority: (was: P3)
Severity: (was: normal)
> JustIce - array store type checks stricter than native verifier
> ---------------------------------------------------------------
>
> Key: BCEL-41
> URL: https://issues.apache.org/jira/browse/BCEL-41
> Project: Commons BCEL
> Issue Type: Bug
> Components: Verifier
> Reporter: Peter Taylor
> Assignee: Apache Commons Developers
>
> Consider the class
> {code}
> public class Demo
> {
> public static void main(String[] args)
> {
> Object[] objs = new Integer[1];
> objs[0] = o();
> }
> private static Object o()
> {
> return null;
> }
> }
> {code}
> It compiles fine, and
> {code}java -verify Demo{code}
> executes without errors. However,
> java org.apache.bcel.verifier.Verifier Demo
> complains:
> {code}
> Pass 3b, method number 1 ['public static void main(String[] arg0)']:
> VERIFIED_REJECTED
> Constraint violated in method 'public static void main(String[] arg0)':
> Instruction AASTORE constraint violated: The type of 'value'
> ('java.lang.Object') is not assignment
> compatible to the components of the array 'arrayref' refers to.
> ('java.lang.Integer')
> {code}
> etc.
> The problem is that while the vmspec2 says "The type of every value stored
> into an array of type reference by an aastore instruction must be assignment
> compatible (§2.6.7) with the component type of the array", the class file
> doesn't contain information on the compile-time component type of the array.
> I suspect the native verifier does nothing about this requirement, leaving
> the VM to throw an ArrayStoreException if problems arise.
> Enver Haase asked me to mention in this report that while the error message
> says "assignment compatible to" and the vmspec2 says "assignment compatible
> with", it's not a case of doing the check the wrong way round.
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