Re: [Sablevm-developer] using a Soot-transformed classpath

[Clark V. <cl...@CS...>]

> is this a soot bug?  generating code for java.lang.Object that declares 
> java.lang.Object as a superclass?  or is there something particular to 
> what i'm doing that forces java.lang.Object as a superclass (i don't see 
> it ...)
> 
> i checked the jasmin disassembly of the transformed java.lang.Object 
> classfile and it does indeed declare '.super java/lang/Object'

The super_class field of the classfile for java.lang.Object should be 0
(ie invalid constant-pool ref), so that sounds like a soot bug.

-- 
ttfn,
clark
cl...@cs...


On Sun, 7 Mar 2004, Chris Pickett wrote:

> Etienne Gagnon wrote:
> > On Fri, Mar 05, 2004 at 11:45:07PM -0500, Chris Pickett wrote:
> > 
> >>>I want to make SableVM use Soot-transformed versions of the non-native 
> >>>portion of Classpath.  I have the output from Soot in the application 
> >>>directory where I try to run SableVM, but the classes aren't getting 
> >>>loaded even with '-c .' specified as an option.
> > 
> > 
> > How about compiling a version of SableVM with
> > --enable-debugging-features and then launching sablevm like this:
> > 
> >  sablevm -v --property sablevm.verbose.methods=true ...
> 
> i use vm->verbose_methods and vm->verbose_instructions all the time :(
> 
> i should have reported more details at first; i was just wondering if 
> somebody knew off the top of their head why it fails.
> 
> anyway, to make it quick:  i followed it through with gdb and it dies 
> loading java.lang.Object because apparently java.lang.Object has a 
> superclass (relevant code follows).
> 
> if i just replace java.lang.Object with the orignal, then it dies 
> whenever it tries to load Spmt.class (which can be deferred by copying 
> over more non-transformed classes).
> 
> i found that if i keep the original Object.class, VMClass.class, and 
> Class.class files, and also put Spmt.class in the root of classpath, 
> then it works fine.  anything less is insufficient.
> 
> however, i would really like to have my special instructions inserted 
> around every method call -- i want to gather statistics on the number of 
> calls we can successfully predict when the whole of classpath is 
> transformed.
> 
> is this a soot bug?  generating code for java.lang.Object that declares 
> java.lang.Object as a superclass?  or is there something particular to 
> what i'm doing that forces java.lang.Object as a superclass (i don't see 
> it ...)
> 
> i checked the jasmin disassembly of the transformed java.lang.Object 
> classfile and it does indeed declare '.super java/lang/Object'
> 
> cheers,
> chris
> 
> ==========================================
> 
> static jint
> _svmf_bootcl_resolve_super_class (_svmt_JNIEnv *env, _svmt_class_info 
> *class)
> {
>    _svmt_JavaVM *vm = env->vm;
>    _svmt_CONSTANT_Class_info **cp_super_class = class->super_class;
> 
>    assert (class->class_loader_info->class_loader == NULL);
> 
>    /* no super class -> we're done */
>    if (CANNOT_DREF (cp_super_class))
>      {
>        /* this must be "java/lang/Object" */
>        /* and it must be a public non-abstract non-final class */
>        if (strcmp (class->name, "java/lang/Object") != 0 ||
>            class->class_loader_info->class_loader != NULL ||
>            (!_svmf_is_set_flag (class->access_flags, SVM_ACC_PUBLIC)) ||
>            _svmf_is_set_flag (class->access_flags, SVM_ACC_FINAL) ||
>            _svmf_is_set_flag (class->access_flags, SVM_ACC_INTERFACE) ||
>            _svmf_is_set_flag (class->access_flags, SVM_ACC_ABSTRACT))
>          {
>            _svmf_error_VerifyError (env);
>            return JNI_ERR;
>          }
> 
>        return JNI_OK;
>      }
> 
>    if (DREF (cp_super_class, tag) != SVM_CONSTANT_Class ||
>        CANNOT_DREF (DREF (cp_super_class, name)) ||
>        DREF (DREF (cp_super_class, name), tag) != SVM_CONSTANT_Utf8 ||
>        DREF (DREF (cp_super_class, name), value)[0] == '[')
>      {
>        _svmf_error_ClassFormatError (env);
>        return JNI_ERR;
>      }
> 
>    {
>      _svmt_type_node type = { NULL, NULL, NULL, NULL, NULL };
> 
>      type.name = DREF (DREF (cp_super_class, name), value);
> 
>      if (_svmm_tree_find_type
>          (vm->class_loading.boot_loader.partially_derived_type_tree,
>           &type) != NULL)
>        {
> =>      _svmf_error_ClassCircularityError (env);
>          return JNI_ERR;
>        }
>    }
> 
> 
> 
> 
> 
> 
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