Re: [drlvm] HARMONY-956 - problem w/ DRLVM classloader

Vladimir Ivanov Thu, 10 Aug 2006 21:32:06 -0700

Seems, that drlvm rejects valid code when 'end_pc' value for exception handler is equal to code array length.

At least, when I update value for 'end_pc' in my simple class it was rejected by drlvm and accepted by RI.

Thanks, Vladimir

More details:

2 class attached: test.class.ref - generated by javac,

test.class - updated (line 108 for file belove was updated: 8 -> 10)

------------------------- test.code------------------------

/**
* Generated ccode file
* @author VMTT (Virtual Machine Testing Tools)
* @version 1.0
* @lastmod: Fri Aug 11 11:20:30 NOVST 2006
*/

magic = xCAFEBABE

minor_version = 0

major_version = 48

constant_pool_count = 18

constant_pool {
/* #1 */ Method = #5 #14
/* #2 */ Class = #15
/* #3 */ Method = #2 #14
/* #4 */ Class = #16
/* #5 */ Class = #17
/* #6 */ UTF8 = "<init>"
/* #7 */ UTF8 = "()V"
/* #8 */ UTF8 = "Code"
/* #9 */ UTF8 = "LineNumberTable"
/* #10 */ UTF8 = "main"
/* #11 */ UTF8 = "([Ljava/lang/String;)V"
/* #12 */ UTF8 = "SourceFile"
/* #13 */ UTF8 = "test.java"
/* #14 */ NameAndType = #6 #7
/* #15 */ UTF8 = "java/lang/Exception"
/* #16 */ UTF8 = "test"
/* #17 */ UTF8 = "java/lang/Object"
}

access_flags = PUBLIC SUPER // x21

this_class = #4 // "test"

super_class = #5 // "java/lang/Object"

interfaces_count = 0

interfaces {
}

fields_count = 0

methods_count = 2

methods {
method {
    access_flag = PUBLIC // x01
    name_index = #6 // "<init>"
    descriptor_index = #7 // "()V"
    attributes_count = 1
      attributes {
        attribute Code {
          attribute_name_index = #8 // "Code"
          attribute_length = 29
          max_stack = 1
          max_locals = 1
          code_length = 5
          code asm {
          0: aload_0
          1: invokespecial #1 // "java/lang/Object" "<init>" "()V"
          4: return
          }
          exception_table_length = 0
          attributes_count = 1
            attributes {
              attribute LineNumberTable {
                attribute_name_index = #9 // "LineNumberTable"
                attribute_length = 6
                line_number_table_length = 1
                line_number_table {
                    // start_pc line_number
                    0 1
                }
              }
            }
        }
      }
}
method {
    access_flag = PUBLIC STATIC // x09
    name_index = #10 // "main"
    descriptor_index = #11 // "([Ljava/lang/String;)V"
    attributes_count = 1
      attributes {
        attribute Code {
          attribute_name_index = #8 // "Code"
          attribute_length = 50
          max_stack = 2
          max_locals = 2
          code_length = 10
          code asm {
          0: new #2 // "java/lang/Exception"
          3: dup
          4: invokespecial #3 // "java/lang/Exception" "<init>" "()V"
          7: athrow
          8: astore_1
          9: return
          }
          exception_table_length = 1
          exception_table {
            // start_pc end_pc handler_pc catch_type
            0 10 8 2
          }
          attributes_count = 1
            attributes {
              attribute LineNumberTable {
                attribute_name_index = #9 // "LineNumberTable"
                attribute_length = 14
                line_number_table_length = 3
                line_number_table {
                    // start_pc line_number
                    0 4
                    8 5
                    9 7
                }
              }
            }
        }
      }
}
}

attributes_count = 1
attributes {
attribute SourceFile {
    attribute_name_index = #12 // "SourceFile"
    attribute_length = 2
    sourcefile_index = #13 // "test.java"
}
}

---------------------------------------------------------------

Output:

C:\tmp\vm_tool>java -showversion test
java version "1.4.2_10"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_10-b03)
Java HotSpot(TM) Client VM (build 1.4.2_10-b03, mixed mode)

C:\tmp\vm_tool>C:\jdk1.5.0_06\bin\java -showversion test
java version "1.5.0_06"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_06-b05)
Java HotSpot(TM) Client VM (build 1.5.0_06-b05 , mixed mode)

C:\tmp\vm_tool>C:\harmony\drlvm1.5\build\win_ia32_msvc_debug\deploy\jre\bin\java -Dvm.assert_dialog=false -cp . -showversion test
java version "1.5.0"
pre-alpha : not complete or compatible
svn = r430643, (Aug 11 2006), Windows/ia32/msvc 1310, debug build
http://incubator.apache.org/harmony
vf_debug: VerifyError: (class: test, method: main([Ljava/lang/String;)V) Handler pc is out of range
java.lang.VerifyError: (class: test, method: main([Ljava/lang/String;)V) Handler pc is out of range
        at java.lang.VMClassRegistry.defineClass()
        at java.lang.ClassLoader.defineClass()
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:68)
        at java.net.URLClassLoader.findClassImpl (URLClassLoader.java:1130)
        at java.net.URLClassLoader$4.run(URLClassLoader.java:617)
        at java.net.URLClassLoader$4.run(URLClassLoader.java:616)
        at java.security.AccessController.doPrivilegedImpl ()
        at java.security.AccessController.doPrivileged()
        at java.net.URLClassLoader.findClass(URLClassLoader.java:614)
        at java.lang.ClassLoader.loadClass()
        at java.net.URLClassLoader$SubURLClassLoader.loadClass (URLClassLoader.java:116)

C:\tmp\vm_tool>C:\harmony\classlib1.5\deploy\jdk\jre\bin\java.exe -cp . -showversion test
java version 1.5 (subset)

C:\tmp\vm_tool>

On 8/10/06, Geir Magnusson Jr <[EMAIL PROTECTED]> wrote:

Anton Luht wrote:
> Hello,
>
> DRLVM has  an (undocumented?) option to switch off verifier
> -Dvm.use_verifier=false . With this option activemq starts without
> crash. Verifier seem to be the blocker.

Aw... I was hoping you'd tell us what the problem was.   Any clue?

geir

>
> On 8/8/06, Geir Magnusson Jr <[EMAIL PROTECTED]> wrote:
>>
>>
>> Gregory Shimansky wrote:
>> > On Tuesday 08 August 2006 00:01 Geir Magnusson Jr wrote:
>> >> Ok - I made that fix and still seem to have a problem, even after a
>> >> clean rebuild.  I guess I should figure out how to turn on the
>> trace...
>> >
>> > The problem is that class loader does not chain VerifyError to
>> > NoClassDefFoundError so debugging such problems is diffucult without
>> tracing.
>> > I think this is a place for improvement in drlvm.
>> >
>> > I tried to fix the problem and found out that verifier just doesn't
>> understand
>> > exception handlers which point to the code length address (code end
>> + 1). It
>> > is a surprise that this problem didn't appear earlier.
>>
>> App-oriented testing... :)
>>
>> >
>> > My patch attached to JIRA attempts to fix the problem in verifier
>> only, the
>> > application still fails to start. In default mode it exits silently,
>> I didn't
>> > find any exception logs or something. When using interpreter -Xint
>> it fails
>> > with ArrayStoreException still without any stack trace. I'll try to
>> find out
>> > what is happening.
>>
>> Nice work.  Thanks for doing this...
>>
>> geir
>>
>> >
>> >> Anton Luht wrote:
>> >>> Hello,
>> >>>
>> >>> The problem is with verifier.
>> >>>
>> >>> The code in Verifier.cpp:
>> >>>
>> >>>        if( ( start_pc >= len ) || ( end_pc >= len ) || (
>> handler_pc >=
>> >>> len ) )
>> >>> ...
>> >>>
>> >>>            result = VER_ErrorHandler;
>> >>>
>> >>> I've modified error logging a bit to log values of start_pc, end_pc,
>> >>> handler_pc and len and that's the output:
>> >>>
>> >>>
>> >>> Loading message broker from: xbean:activemq.xml
>> >>> vf_debug: VerifyError: (class:
>> >>> edu/emory/mathcs/backport/java/util/concurrent/lo
>> >>> cks/ReentrantLock$NonfairSync, method: lockInterruptibly()V, len:
>> 103,
>> >>> start_pc:
>> >>> 87, end_pc: 103, handler_pc: 21) Handler pc is out of range
>> >>> vf_debug: verifying class
>> >>> edu/emory/mathcs/backport/java/util/concurrent/locks/R
>> >>> eentrantLock (method <init>()V) couldn't load class
>> >>> "edu/emory/mathcs/backport/j
>> >>> ava/util/concurrent/locks/ReentrantLock$NonfairSync"
>> >>> vf_debug: VerifyError:
>> >>> edu/emory/mathcs/backport/java/util/concurrent/locks/Reen
>> >>> trantLock$NonfairSync
>> >>> Failed to execute main task. Reason: java.lang.NoClassDefFoundError:
>> >>> edu/emory/m
>> >>> athcs/backport/java/util/concurrent/locks/ReentrantLock$NonfairSync
>> >>>
>> >>> I'm not an expert in verification but seems like
>> >>>
>> >>> end_pc >= len
>> >>> should be replaced with
>> >>> end_pc > len
>> >>>
>> >>> On 8/5/06, Geir Magnusson Jr <[EMAIL PROTECTED]> wrote:
>> >>>> Anyone interested? :)
>> >
>>
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>>
>
>

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test.class.ref
Description: application/java

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Re: [drlvm] HARMONY-956 - problem w/ DRLVM classloader

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