Review Request: Regression Zero fails to handle fast_aldc and fast_aldc_w in hs20

[Dr Andrew John Hughes]

On 02:07 Thu 21 Apr     , Xerxes Rånby wrote:
> On 2011-04-21 00:39, Dr Andrew John Hughes wrote:
> > On 16:00 Wed 20 Apr     , Xerxes Rånby wrote:
> >> Hi
> >>
> >> hs20 uses two new internal instructions fast_aldc and fast_aldc_w.
> >> see: openjdk/hotspot/src/share/vm/interpreter/bytecodes.hpp
> >>
> >> This webrev fix by backporting Zero fixes from OpenJDK bug 7032458 and 7030207.
> >> http://labb.zafena.se/openjdk/pr696-zero-fast_aldc-and-fast_aldc_w-regression-hs20/
> >>
> >> The webrev are made against hsx20
> >> http://hg.openjdk.java.net/hsx/hsx20/master/
> >>
> >> I don't have a bug id for this.
> >
> > Why are you merging together two different changesets?
> 
> Because they both contain parts that are needed to properly fix this 
> Zero regression on hs20 and prevent it from happening again.
> 
> One part that fixes the regression by making the instruction table in 
> sync again from 7032458, and another part from 7030207 that reveals the 
> error if the table gets out of sync again.
> 
> If I quote Gary:
> "It two new internal instructions, _fast_aldc and _fast_aldc_w, but
> it added them *before* _return_register_finalizer, which broke the
> instructions table in bytecodeInterpreter.cpp.  It meant that when
> the C++ interpreter saw _return_register_finalizer it would execute
> opc_default, which should have thrown an error but for the piece of
> the ARM interpreter which hid the error by rewriting the instruction
> to a plain _return.  I didn't see it before because I was doing
> debug builds, and the C++ interpreter only uses the instructions
> table for product builds."
> http://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2011-March/005074.html
> 

Are there bits of each changeset being left out?  It's just it's easier
to track if there is a 1-to-1 correspondence.

> Cheers
> Xerxes

-- 
Andrew :)

Free Java Software Engineer
Red Hat, Inc. (http://www.redhat.com)

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