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Bug ID: 6716785 implicit null checks not triggering with CompressedOops
6716785 : implicit null checks not triggering with CompressedOops

Details
Type:
Bug
Submit Date:
2008-06-19
Status:
Closed
Updated Date:
2011-03-08
Project Name:
JDK
Resolved Date:
2011-03-08
Component:
hotspot
OS:
linux_suse_sles_10,linux
Sub-Component:
runtime
CPU:
x86
Priority:
P2
Resolution:
Fixed
Affected Versions:
hs13,6u6p
Fixed Versions:
hs13

Related Reports
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Sub Tasks

Description
See comments.

                                    

Comments
EVALUATION

This fix has been checked in for both hs13 (snapshot for b03) and in hs14.
                                     
2008-07-22
EVALUATION

Add code to allocate extra space for java heap (either 1 page or alignment) and unprotect so that implicit null exceptions at heap_base + 1 page fault.
                                     
2008-06-30
SUGGESTED FIX

The ultimate fix should be in runtime, in the short term we may want to have some variant of -UseImplicitNullChecks for narrow oops in C2.
                                     
2008-06-25
EVALUATION

Implict null checks under CompressedOops are not triggering a change on control flow. It appears that the heap_base+1 page is still writeable, so the generated code does not SEGV as expected.
                                     
2008-06-25
EVALUATION

-
                                     
2008-06-19



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