JDK-6813212 : factor duplicated assembly code for general subclass check (for 6655638)
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 7
  • Priority: P3
  • Status: Resolved
  • Resolution: Fixed
  • OS: generic
  • CPU: generic
  • Submitted: 2009-03-04
  • Updated: 2010-04-02
  • Resolved: 2009-04-02
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JDK 6 JDK 7 Other
6u18Fixed 7Fixed hs15Fixed
Related Reports
Relates :  
JDK-6840775 - Multiple JVM crashes seen with 1.6.0_10 through early access of 1.6.0_14 - possibly related to GC
Description
The assembly code for the general subclass check is duplicated (with minor variations) in interp_masm, stubGenerator, and c1_LIRAssembler.  In order to control the code shape more directly, we will factor it into a new subroutine MacroAssembler::check_klass_subtype.

This will let us use the subroutine in a new places, such as code for a direct method handle which adapts to a wider incoming argument type.

It will also reduce the number of modifications required to add enhancements to subtype checking, such as for the interface injection project.
Comments
EVALUATION http://hg.openjdk.java.net/jdk7/hotspot-comp/hotspot/rev/c517646eef23
14-03-2009
SUGGESTED FIX http://cr.openjdk.java.net/~jrose/6813212/
08-03-2009