JDK-6589823 : Error: meet not symmetric
  • Type: Bug
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: hs12
  • Priority: P4
  • Status: Closed
  • Resolution: Fixed
  • OS: solaris_9
  • CPU: sparc
  • Submitted: 2007-08-06
  • Updated: 2011-04-25
  • Resolved: 2011-04-25
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JDK 7 Other
7Fixed hs21Fixed
Related Reports
Relates :  
JDK-6716441 - error in meet with +DoEscapeAnalysis
Relates :  
JDK-6589186 - 20070719212032.jrose.6337834 putback produces amd64 jvmg error: Bad immediate dominator info
Description
It could be duplicate of 6589186 but the failure is different.
64-bits VM sparcv9 start failing after John's putback
20070719212032.jrose.6337834

jaberwocky% gamma -Xcomp -XX:CompileThreshold=100 -Xss4m -Xverify:all -XX:+CompileTheWorld -XX:CompileTheWorldStartAt=8000 -Xbootclasspath/p:/net/vmsqe.sfbay/export/backup/testbase/CompileTheWorld/jarfiles/jck13classes.jar
...
CompileTheWorld (11068) : javasoft/sqe/tests/lang/conv080/conv08001/conv08001i
CompileTheWorld (11069) : javasoft/sqe/tests/lang/conv081/conv08101/conv08101
=== Meet Not Symmetric ===
t   =                   javasoft/sqe/tests/lang/conv081/conv08101/SomeClass:TopPTR *[int:max..0:www]:AnyNull:exact*
this=                   javasoft/sqe/tests/lang/conv081/conv08101/ImmediateSubclass:TopPTR *[int:5:www]:AnyNull:exact*
mt=(t meet this)=       javasoft/sqe/tests/lang/conv081/conv08101/ImmediateSubclass:TopPTR *[int:5:www]:AnyNull:exact*
t_dual=                 javasoft/sqe/tests/lang/conv081/conv08101/SomeClass *[int:>=0]:NotNull:exact*
this_dual=              javasoft/sqe/tests/lang/conv081/conv08101/ImmediateSubclass *[int:5]:NotNull:exact*
mt_dual=                javasoft/sqe/tests/lang/conv081/conv08101/ImmediateSubclass *[int:5]:NotNull:exact*
mt_dual meet t_dual=    javasoft/sqe/tests/lang/conv081/conv08101/SomeClass *[int:>=0]:NotNull*
mt_dual meet this_dual= javasoft/sqe/tests/lang/conv081/conv08101/ImmediateSubclass *[int:5]:NotNull:exact*
# To suppress the following error report, specify this argument
# after -XX: or in .hotspotrc:  SuppressErrorAt=/type.cpp:520
#
# An unexpected error has been detected by Java Runtime Environment:
#
#  Internal Error (/net/prt-sol-sparc-3/tmp/PrtBuildDir/workspace/src/share/vm/opto/type.cpp:520), pid=838, tid=8
#  Error: meet not symmetric
#
# Java VM: Java HotSpot(TM) 64-Bit Server VM (20070719212032.jrose.6337834-fastdebug compiled mode solaris-sparc)
# An error report file with more information is saved as:
# /tmp/kvn/ctw/hs_err_pid838.log
#
# If you would like to submit a bug report, please visit:
#   http://java.sun.com/webapps/bugreport/crash.jsp
# The crash happened outside the Java Virtual Machine in native code.
# See problematic frame for where to report the bug.
#
Current thread is 8
Dumping core ...
Abort
Comments
EVALUATION http://hg.openjdk.java.net/jdk7/hotspot-rt/hotspot/rev/8e72cd29b15d
21-03-2011
PUBLIC COMMENTS Array pointers meet must fall to bottom if exact array klasses in upper lattice are not equal or super klass is exact.
07-03-2011
EVALUATION http://hg.openjdk.java.net/jdk7/hotspot-comp/hotspot/rev/8e72cd29b15d
06-03-2011
EVALUATION Tom added next code into C2 and I extended it to show the problem: const TypeAryPtr* obj = TypeAryPtr::make(TypePtr::NotNull, TypeAry::make(TypeInstPtr::BOTTOM,TypeInt::POS), NULL, true, 0); const TypeAryPtr* num = TypeAryPtr::make(TypePtr::NotNull, TypeAry::make(TypeInstPtr::make(TypePtr::BotPTR, env()->Integer_klass()->super()),TypeInt::POS), NULL, true, 0); const Type* m1 = obj->cast_to_exactness(true)->meet(num->cast_to_exactness(true)); const Type* m2 = obj->cast_to_exactness(true)->meet(num->cast_to_exactness(false)); const Type* m3 = obj->cast_to_exactness(false)->meet(num->cast_to_exactness(true)); const Type* m4 = obj->cast_to_exactness(false)->meet(num->cast_to_exactness(false)); const Type* j1 = obj->cast_to_exactness(true)->join(num->cast_to_exactness(true)); const Type* j2 = obj->cast_to_exactness(true)->join(num->cast_to_exactness(false)); const Type* j3 = obj->cast_to_exactness(false)->join(num->cast_to_exactness(true)); const Type* j4 = obj->cast_to_exactness(false)->join(num->cast_to_exactness(false)); const TypeAryPtr* thr = TypeAryPtr::make(TypePtr::NotNull, TypeAry::make(TypeInstPtr::make(TypePtr::BotPTR, env()->Thread_klass()),TypeInt::POS), NULL, true, 0); const Type* tm1 = thr->cast_to_exactness(true)->meet(num->cast_to_exactness(true)); const Type* tm2 = thr->cast_to_exactness(true)->meet(num->cast_to_exactness(false)); const Type* tm3 = thr->cast_to_exactness(false)->meet(num->cast_to_exactness(true)); const Type* tm4 = thr->cast_to_exactness(false)->meet(num->cast_to_exactness(false)); const Type* tj1 = thr->cast_to_exactness(true)->join(num->cast_to_exactness(true)); const Type* tj2 = thr->cast_to_exactness(true)->join(num->cast_to_exactness(false)); const Type* tj3 = thr->cast_to_exactness(false)->join(num->cast_to_exactness(true)); const Type* tj4 = thr->cast_to_exactness(false)->join(num->cast_to_exactness(false)); const TypeAryPtr* str = TypeAryPtr::make(TypePtr::NotNull, TypeAry::make(TypeInstPtr::make(TypePtr::BotPTR, env()->String_klass()),TypeInt::POS), NULL, true, 0); const Type* sm1 = str->cast_to_exactness(true)->meet(num->cast_to_exactness(true)); const Type* sm2 = str->cast_to_exactness(true)->meet(num->cast_to_exactness(false)); const Type* sm3 = str->cast_to_exactness(false)->meet(num->cast_to_exactness(true)); const Type* sm4 = str->cast_to_exactness(false)->meet(num->cast_to_exactness(false)); const Type* sj1 = str->cast_to_exactness(true)->join(num->cast_to_exactness(true)); const Type* sj2 = str->cast_to_exactness(true)->join(num->cast_to_exactness(false)); const Type* sj3 = str->cast_to_exactness(false)->join(num->cast_to_exactness(true)); const Type* sj4 = str->cast_to_exactness(false)->join(num->cast_to_exactness(false));
04-03-2011
EVALUATION Currently I can't reproduce the bug failure after next John's changes (in 2007): 6603492: multianewarray should generate same code as anewarray for 1-d arrays. Static subtypes analysis in gen_subtype_check() hides this problem as well. So one of the option is to derefer this bug from jdk 7. But bug is still here and it can be reproduced by hand if you call TypeOopPtr::filter() for next types (ImmediateSubclass is subclass of SomeClass): t1 = SomeClass *[int:>=0]:NotNull:exact* t2 = ImmediateSubclass *[int:5]:NotNull:exact* The main problem is TypeAryPtr::xmeet() executes TypeAry::meet() separate from TypeAryPtr type lattice analysis. Exactness of TypeAryPtr should affect result of TypeAry::meet() but it does not: === Meet Not Symmetric === t = SomeClass:TopPTR *,iid=top[int:max..0]:AnyNull:exact *,iid=top this= ImmediateSubclass:TopPTR *,iid=top[int:5]:AnyNull:exact *,iid=top mt=(t meet this)= ImmediateSubclass:TopPTR *,iid=top[int:5]:AnyNull:exact *,iid=top t_dual= SomeClass *[int:>=0]:NotNull:exact * this_dual= ImmediateSubclass *[int:5]:NotNull:exact * mt_dual= ImmediateSubclass *[int:5]:NotNull:exact * mt_dual meet t_dual= SomeClass *[int:>=0]:NotNull * mt_dual meet this_dual= ImmediateSubclass *[int:5]:NotNull:exact * It fails since "mt_dual meet t_dual" != "t_dual". Here is how TypeInstPtr::xmeet() works in similar case: t = SomeClass:AnyNull:exact *,iid=top this= ImmediateSubclass:AnyNull:exact *,iid=top mt=(t meet this)= SomeClass:NotNull * t_dual= SomeClass:NotNull:exact* this_dual= ImmediateSubclass:NotNull:exact* mt_dual= SomeClass:AnyNull* mt_dual meet t_dual= SomeClass:NotNull:exact* mt_dual meet this_dual= ImmediateSubclass:NotNull:exact* Note that "mt" is dropped down in lattice. Here is code which does it: // Since klasses are different, we require a LCA in the Java // class hierarchy - which means we have to fall to at least NotNull. if( ptr == TopPTR || ptr == AnyNull || ptr == Constant ) ptr = NotNull; instance_id = InstanceBot; // Now we find the LCA of Java classes ciKlass* k = this_klass->least_common_ancestor(tinst_klass); return make( ptr, k, false, NULL, off, instance_id ); There are no such code in TypeAryPtr. And type system falls apart when I tried to implement (seems wrong) the same functionality in TypeAryPtr by coping code from TypeInstPtr::xmeet(): === Meet Not Symmetric === t = SomeClass *[int:5]:NotNull:exact * this= ImmediateSubclass *[int:5]:NotNull:exact * mt=(t meet this)= SomeClass *[int:>=0] * t_dual= SomeClass:TopPTR *,iid=top[int:5]:AnyNull:exact *,iid=top this_dual= ImmediateSubclass:TopPTR *,iid=top[int:5]:AnyNull:exact *,iid=top mt_dual= SomeClass:TopPTR *,iid=top[int:max..0]:TopPTR *,iid=top mt_dual meet t_dual= SomeClass:TopPTR *,iid=top[int:max..0]:AnyNull:exact *,iid=top mt_dual meet this_dual= ImmediateSubclass:TopPTR *,iid=top[int:5]:AnyNull:exact *,iid=top Here is webrev, new code is under UseNewCode: http://cr.openjdk.java.net/~kvn/6589823/webrev Test case: /net/sqenfs-1/export1/comp/vm/testbase/jck/6b/dist/JCK-runtime-6b/tests/lang/CONV/conv081/conv08101/conv08101.java
01-03-2011