Need a VM that accepts, if not understands, JVM_CONSTANT_ModuleId

[Jonathan Gibbons]

Mark, Karen,

Was there a resolution to this?

-- Jon


Mark Reinhold wrote:
> I spent some time this weekend trying to get the basic end-to-end
> module-loading mechanism working.  I pretty quickly ran up against the
> fact that HotSpot -- not even in Karen's prototype version -- doesn't
> grok constant-pool items with tag 13 for CONSTANT_ModuleId_info and
> instead throws a ClassFormatError, as well it should in this case.
>
> I tried hacking on jvm.h and classFileParser.cpp to make this work but
> failed, most likely because I'm missing something obvious.
>
> Karen, does the following patch make any sense?  If not, could you please
> send me one -- or push one -- that does?
>
> Note that right now I don't need the VM to do anything with these items,
> I just need it not to give up when it does see them.
>
> (For the moment I worked around this problem by using a hacked-up copy of
>  the ASM library to strip the offending items and related attributes.)
>
> Thanks,
> - Mark
>
>   
> ------------------------------------------------------------------------
>
> diff -r dae503d9f04c src/share/vm/classfile/classFileParser.cpp
> --- a/src/share/vm/classfile/classFileParser.cpp	Thu Feb 26 10:57:13 2009 -0800
> +++ b/src/share/vm/classfile/classFileParser.cpp	Sun Mar 08 20:02:11 2009 -0700
> @@ -159,6 +159,14 @@
>            cp->name_and_type_at_put(index, name_index, signature_index);
>          }
>          break;
> +      case JVM_CONSTANT_ModuleId :
> +        {
> +          cfs->guarantee_more(5, CHECK);  // name_index, version_index, tag/access_flags
> +          u2 name_index = cfs->get_u2_fast();
> +          u2 version_index = cfs->get_u2_fast();
> +          // ## cp->name_and_type_at_put(index, name_index, signature_index);
> +        }
> +	break;
>        case JVM_CONSTANT_Utf8 :
>          {
>            cfs->guarantee_more(2, CHECK);  // utf8_length
> @@ -301,6 +309,8 @@
>            signature_ref_index, CHECK_(nullHandle));
>          break;
>        }
> +      case JVM_CONSTANT_ModuleId : // ##
> +	break;
>        case JVM_CONSTANT_Utf8 :
>          break;
>        case JVM_CONSTANT_UnresolvedClass :         // fall-through
> diff -r dae503d9f04c src/share/vm/prims/jvm.h
> --- a/src/share/vm/prims/jvm.h	Thu Feb 26 10:57:13 2009 -0800
> +++ b/src/share/vm/prims/jvm.h	Sun Mar 08 20:02:11 2009 -0700
> @@ -1038,8 +1038,11 @@
>      JVM_CONSTANT_Fieldref,
>      JVM_CONSTANT_Methodref,
>      JVM_CONSTANT_InterfaceMethodref,
> -    JVM_CONSTANT_NameAndType
> +    JVM_CONSTANT_NameAndType,
> +    JVM_CONSTANT_ModuleId
>  };
> +
> +#define JVM_CONSTANT_MAX JVM_CONSTANT_ModuleId
>  
>  /* Used in the newarray instruction. */
>  
> diff -r dae503d9f04c src/share/vm/utilities/constantTag.cpp
> --- a/src/share/vm/utilities/constantTag.cpp	Thu Feb 26 10:57:13 2009 -0800
> +++ b/src/share/vm/utilities/constantTag.cpp	Sun Mar 08 20:02:11 2009 -0700
> @@ -59,6 +59,9 @@
>      case JVM_CONSTANT_NameAndType :
>        st->print("NameAndType");
>        break;
> +    case JVM_CONSTANT_ModuleId :
> +      st-print("ModuleId");
> +      break;
>      case JVM_CONSTANT_Utf8 :
>        st->print("Utf8");
>        break;
> diff -r dae503d9f04c src/share/vm/utilities/constantTag.hpp
> --- a/src/share/vm/utilities/constantTag.hpp	Thu Feb 26 10:57:13 2009 -0800
> +++ b/src/share/vm/utilities/constantTag.hpp	Sun Mar 08 20:02:11 2009 -0700
> @@ -76,7 +76,7 @@
>    bool is_symbol() const            { return is_utf8(); }
>  
>    constantTag(jbyte tag) {
> -    assert((tag >= 0 && tag <= JVM_CONSTANT_NameAndType) ||
> +    assert((tag >= 0 && tag <= JVM_CONSTANT_MAX) ||
>             (tag >= JVM_CONSTANT_InternalMin && tag <= JVM_CONSTANT_InternalMax), "Invalid constant tag");
>      _tag = tag;
>    }
>