[
https://issues.apache.org/jira/browse/BCEL-123?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13511912#comment-13511912
]
Emmanuel Bourg edited comment on BCEL-123 at 2/23/15 8:23 PM:
--------------------------------------------------------------
MethodGen mistakenly fills in LocalVariableTableGen from both
LocalVariableTable and LocalVariableTypeTable. In parsing
LocalVariableTypeTable, it incorrectly reads the signatures with generics. As
a result, the LocalVariableTable is corrupted.
Here is an example:
{code}
public class VariableTableBug
{
public String getFirstItem( final List< String > list )
{
int index = 0;
String result = list.get( index );
return result;
}
public static void main( final String[] args ) throws Exception
{
// find the resource that is our class
Class< VariableTableBug > clazz = VariableTableBug.class;
String resource = clazz.getName().replace( '.', '/' ) + ".class";
// load it using BCEL
JavaClass javaClass = new ClassParser(
clazz.getClassLoader().getResourceAsStream( resource ),
resource ).parse();
// convert everything to a ClassGen
ClassGen classGen = new ClassGen( javaClass );
// find them getFirstItem method
Method getFirstItemMethod = null;
for ( Method method : classGen.getMethods() )
{
if ( method.getName().equals( "getFirstItem" ) )
{
getFirstItemMethod = method;
break;
}
}
// dump the LocalVariableTable attribute
System.out.println( "LocalVariableTable of original" );
System.out.println( "------------------------------" );
for ( LocalVariable localVariable :
getFirstItemMethod.getLocalVariableTable().getLocalVariableTable() )
{
System.out.println( localVariable.getName() + "\t" +
localVariable.getIndex() + "\t" + localVariable.getSignature() );
}
System.out.println();
// dump the LocalVariableTypeTable attribute
for ( Attribute attribute : getFirstItemMethod.getCode().getAttributes() )
{
if ( attribute instanceof LocalVariableTypeTable )
{
System.out.println( "LocalVariableTypeTable of original" );
System.out.println( "----------------------------------" );
for ( LocalVariable localVariable : ( (LocalVariableTypeTable)
attribute ).getLocalVariableTypeTable() )
{
System.out.println( localVariable.getName() + "\t" +
localVariable.getIndex() + "\t" + localVariable.getSignature() );
}
}
}
System.out.println();
// now convert to a MethodGen
MethodGen methodGen = new MethodGen( getFirstItemMethod,
classGen.getClassName(),
classGen.getConstantPool() );
// dump the LocalVariableTable
System.out.println( "LocalVariableTable of MethodGen" );
System.out.println( "-------------------------------" );
for ( LocalVariableGen localVariableGen : methodGen.getLocalVariables() )
{
System.out.println( localVariableGen.getName() + "\t" +
localVariableGen.getIndex() + "\t" + localVariableGen.getType() );
}
}
}
{code}
was (Author: [email protected]):
MethodGen mistakenly fills in LocalVariableTableGen from both
LocalVariableTable and LocalVariableTypeTable. In parsing
LocalVariableTypeTable, it incorrectly reads the signatures with generics. As
a result, the LocalVariableTable is corrupted.
Here is an example:
public class VariableTableBug
{
public String getFirstItem( final List< String > list )
{
int index = 0;
String result = list.get( index );
return result;
}
public static void main( final String[] args ) throws Exception
{
// find the resource that is our class
Class< VariableTableBug > clazz = VariableTableBug.class;
String resource = clazz.getName().replace( '.', '/' ) + ".class";
// load it using BCEL
JavaClass javaClass = new ClassParser(
clazz.getClassLoader().getResourceAsStream( resource ),
resource ).parse();
// convert everything to a ClassGen
ClassGen classGen = new ClassGen( javaClass );
// find them getFirstItem method
Method getFirstItemMethod = null;
for ( Method method : classGen.getMethods() )
{
if ( method.getName().equals( "getFirstItem" ) )
{
getFirstItemMethod = method;
break;
}
}
// dump the LocalVariableTable attribute
System.out.println( "LocalVariableTable of original" );
System.out.println( "------------------------------" );
for ( LocalVariable localVariable :
getFirstItemMethod.getLocalVariableTable().getLocalVariableTable() )
{
System.out.println( localVariable.getName() + "\t" +
localVariable.getIndex() + "\t" + localVariable.getSignature() );
}
System.out.println();
// dump the LocalVariableTypeTable attribute
for ( Attribute attribute : getFirstItemMethod.getCode().getAttributes() )
{
if ( attribute instanceof LocalVariableTypeTable )
{
System.out.println( "LocalVariableTypeTable of original" );
System.out.println( "----------------------------------" );
for ( LocalVariable localVariable : ( (LocalVariableTypeTable)
attribute ).getLocalVariableTypeTable() )
{
System.out.println( localVariable.getName() + "\t" +
localVariable.getIndex() + "\t" + localVariable.getSignature() );
}
}
}
System.out.println();
// now convert to a MethodGen
MethodGen methodGen = new MethodGen( getFirstItemMethod,
classGen.getClassName(),
classGen.getConstantPool() );
// dump the LocalVariableTable
System.out.println( "LocalVariableTable of MethodGen" );
System.out.println( "-------------------------------" );
for ( LocalVariableGen localVariableGen : methodGen.getLocalVariables() )
{
System.out.println( localVariableGen.getName() + "\t" +
localVariableGen.getIndex() + "\t" + localVariableGen.getType() );
}
}
}
> MethodGen: LocalVariableTableGen issues
> ---------------------------------------
>
> Key: BCEL-123
> URL: https://issues.apache.org/jira/browse/BCEL-123
> Project: Commons BCEL
> Issue Type: Bug
> Components: Main
> Affects Versions: unspecified
> Environment: Operating System: Linux
> Platform: PC
> Reporter: Matthew Wilson
> Assignee: Apache Commons Developers
>
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
