Default method resolution question

[David Holmes]

Hi Vladimir,

I don't know if it would make any difference but is that the TreeSet 
from rt.jar or alt-rt.jar ?

David

On 16/09/2013 9:39 PM, Vladimir Ivanov wrote:
> Hi,
>
> I hit an assert when doing CHA for a default method during JIT-compilation:
> #  Internal Error (src/share/vm/code/dependencies.cpp:1411)
> #  assert(wf.check_method_context(ctxk, m)) failed: proper context
>
> Call stack:
> Dependencies::find_unique_concrete_method
> ciMethod::find_monomorphic_target
> Compile::optimize_inlining
> Compile::optimize_virtual_call
> Parse::do_call
> ...
>
> What does check_method_context do it resolves the method again and then
> do pointer comparison to check that result it the same. And it doesn't
> work for default methods:
>   Dependency method not found in the associated context:
>    context = javasoft.sqe.tests.api.java.util.TreeSet.SharedData$1
>    method =  java.util.TreeSet::parallelStream
>    found =  java.util.TreeSet::parallelStream
>
> My main suspicion is that the problem is in check_method_context (the
> check is imprecise and already has a number of exceptions), but I want
> to double-check. Does method resolution behavior I see look normal?
>
> Here are my observations.
>
> Method passed into Dependencies::find_unique_concrete_method:
> {method}
>   - this oop:          0xb69eab58
>   - method holder:     'java/util/TreeSet'
>   - constants:         0xb69eacd8 constant pool [305] {0xb69eacdc} for
> 'java/util/TreeSet' cache=0xb69eb2b8
>   - access:            0x80001041  public volatile synthetic
>   - name:              'parallelStream'
>   - signature:         '()Ljava/util/stream/Stream;'
>   - max stack:         2
>   - max locals:        1
>   - size of params:    1
>   - method size:       14
>   - highest level:     4
>   - vtable index:      22
>   - i2i entry:         0xfa00b940
>   - adapters:          AHE at 0x081982ac: 0xa0000000 i2c: 0xfa0aaec0 c2i:
> 0xfa0aaf49 c2iUV: 0xfa0aaf28
>   - compiled entry     0xfa1704ec
>   - code size:         5
>   - code start:        0xb69eab44
>   - code end (excl):   0xb69eab49
>   - method data:       0xb6806b10
>   - checked ex length: 0
>   - localvar length:   0
>   - compiled code: nmethod 584533  988 java.util.TreeSet::parallelStream
> (5 bytes)
>
> Method resolved in check_method_context:
> {method}
>   - this oop:          0xb69ea978
>   - method holder:     'java/util/TreeSet'
>   - constants:         0xb69eacd8 constant pool [305] {0xb69eacdc} for
> 'java/util/TreeSet' cache=0xb69eb2b8
>   - access:            0x1041  public volatile synthetic
>   - name:              'parallelStream'
>   - signature:         'Ljava/util/stream/Stream'
>   - max stack:         2
>   - max locals:        1
>   - size of params:    1
>   - method size:       14
>   - vtable index:      22
>   - i2i entry:         0xfa00b940
>   - adapters:          AHE at 0x081982ac: 0xa0000000 i2c: 0xfa0aaec0 c2i:
> 0xfa0aaf49 c2iUV: 0xfa0aaf28
>   - compiled entry     0xfa0aaf49
>   - code size:         5
>   - code start:        0xb69ea964
>   - code end (excl):   0xb69ea969
>   - method data:       0xb6584270
>   - checked ex length: 0
>   - localvar length:   0
>
> Class hierarchy:
> javasoft.sqe.tests.api.java.util.TreeSet.SharedData$1 extends
> java.util.TreeSet<E>
>
> java.util.TreeSet<E> extends java.util.AbstractSet<E>
>               implements java.util.NavigableSet<E>,
>                  java.lang.Cloneable,
>                  java.io.Serializable
>
> public interface Collection<E> extends Iterable<E> {
>      default Stream<E> parallelStream() { ... }
>
> Original method pointer is acquired through ciMethod::resolve_invoke call.
>
> resolved_method && CallInfo from LinkResolver::resolve_virtual_call:
>
> (dbx) print resolved_method
> resolved_method = {
>      _value  = 0xb69ea978   <=============
>      _thread = 0x8232c00
> }
>
> (dbx) print result
> result = {
>      _resolved_klass       = {
>          _value = 0xb69ea618
>      }
>      _selected_klass       = {
>          _value = 0xb69f3bb0
>      }
>      _resolved_method      = {
>          _value  = 0xb69ea978 <===========
>          _thread = 0x8232c00
>      }
>      _selected_method      = {
>          _value  = 0xb69eab58 <===========
>          _thread = 0x8232c00
>      }
>      _vtable_index         = 22
>      _resolved_appendix    = {
>          _handle = (nil)
>      }
>      _resolved_method_type = {
>          _handle = (nil)
>      }
> }
>
> _resolved_method is the same as computed in check_method_context.
>
> _selected_method is loaded from vtable at linkResolver.cpp:943:
>      selected_method = methodHandle(THREAD,
> inst->method_at_vtable(vtable_index));
>
> Best regards,
> Vladimir Ivanov