Not reproductible crash + unexpected exception?

[Christian Thalinger]

On Mar 3, 2011, at 1:12 PM, Christian Thalinger wrote:
> On Mar 3, 2011, at 9:47 AM, Rémi Forax wrote:
>> Yes. I use an agent so it can have trigger a deoptimization
>> even if I don't understand why ?
> 
> Here is what I get with a debug build:

<snip>

> The assert looks like:
> 
> 7016279: JSR292 Exception when creating CallSites from multiple threads
> 
> Is your source code creating CallSites from multiple threads (massively parallel)?


Scratch that.  I think I found the problem:  the constant pool cache entry is not properly updated after a GC thus resulting in a bogus value for the BSM.

This can either crash or throw an exception depending on the current content of the heap:

resolving bootstrap method for 0xb65daf98 at 2 at cache[18]CP[143]...
result_oop: e4f01720
sun.dyn.DirectMethodHandle 
 - klass: 'sun/dyn/DirectMethodHandle'
 - ---- fields (total size 6 words):
 - private 'vmentry' 'I' @8  -93565868 (fa6c4c54)
 - protected 'vmtarget' 'Ljava/lang/Object;' @12  {method} 'staticBootstrap' '(Ljava/dyn/MethodHandles$Lookup;Ljava/lang/String;Ljava/dyn/MethodType;[Ljava/lang/Object;)Ljava/dyn/CallSite;' in 'jsr335/lambda/optimizer/RT' (b65f2738)
 - private 'type' 'Ljava/dyn/MethodType;' @16  a 'java/dyn/MethodType' = (Ljava/dyn/MethodHandles$Lookup;Ljava/lang/String;Ljava/dyn/MethodType;[Ljava/lang/Object;)Ljava/dyn/CallSite; (e4f00f00)
 - private final 'vmindex' 'I' @20  -2 (fffffffe)
bootstrap method for 0xb65daf98 at 2 retrieved as 0xe4f01720:

...

[GC 16448K->5140K(62848K), 0.1462675 secs]
[GC 21588K->6252K(79296K), 0.1955926 secs]
[GC 39148K->8444K(79296K), 0.5892590 secs]
[GC 41340K->10744K(112192K), 0.6393406 secs]
[GC 76536K->15324K(112192K), 1.2619007 secs]
[GC 81116K->19988K(182592K), 0.9492098 secs]
resolving bootstrap method for 0xb65daf98 at 9 at cache[18]CP[143]...
result_oop: e4f01720
[Ljava.lang.Object; 
 - klass: 'java/lang/Object'[]
 - length: 1
 -   0 : "foo"
bootstrap method for 0xb65daf98 at 9 retrieved as 0xe4f01720:
Exception in thread "main" java.lang.IllegalStateException: no bootstrap method found for invokedynamic
        at Megamorphic2.test(Megamorphic2.java:60)
        at Megamorphic2.main(Megamorphic2.java:52)

-- Christian