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

[Chris P. <chr...@ma...>]

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;
       }
   }