[8u] Request for approval: 8087120: [GCC5] java.lang.StackOverflowError on Zero JVM initialization on non x86 platforms

[Andrew Hughes]

----- Original Message -----
> http://hg.openjdk.java.net/jdk8u/jdk8u-dev/hotspot
> 
> On 11/19/15 9:21 AM, Severin Gehwolf wrote:
> > On Thu, 2015-11-19 at 15:43 +0000, Rob McKenna wrote:
> >> Correct. You need a sponsor. Perhaps Andrew would be willing to help?
> >> Failing that please work with the hotspot group.
> >
> > Thanks, Rob.
> >
> > Hotspot people: To which JDK 8 tree should this get pushed? Andrew,
> > tells me that he can push it for me once we know where :)
> >
> > Thanks,
> > Severin
> >
> >> 	-Rob
> >>
> >> On 19/11/15 09:41, Severin Gehwolf wrote:
> >>> On Wed, 2015-11-18 at 21:08 +0000, Rob McKenna wrote:
> >>>> Approved. Please add a suitable noreg label to the bug.
> >>>>
> >>>> 	-Rob
> >>>
> >>> Another question: Wouldn't I need a sponsor to get this integrated?
> >>> Is
> >>> this being taken care of automatically?
> >>>
> >>> Thanks for your help!
> >>>
> >>> Cheers,
> >>> Severin
> >>>
> >>>> On 18/11/15 10:50, Severin Gehwolf wrote:
> >>>>> Hi,
> >>>>>
> >>>>> I'd like to ask for approval of a Zero-specific hotspot 8
> >>>>> backport.
> >>>>> Currently, the jdk8u forest fails to build the Zero variant
> >>>>> with
> >>>>> GCC 5
> >>>>> due to this:
> >>>>>
> >>>>> src/os_cpu/linux_zero/vm/os_linux_zero.cpp:59:10: error:
> >>>>> function
> >>>>> returns address of local variable [-Werror=return-local-addr]
> >>>>>       return dummy;
> >>>>>              ^
> >>>>> src/os_cpu/linux_zero/vm/os_linux_zero.cpp:58:11: note:
> >>>>> declared
> >>>>> here
> >>>>>       address dummy = (address) &dummy;
> >>>>>               ^
> >>>>> Note: Fedora 22+ have GCC 5. The above problem and the actual
> >>>>> overflow
> >>>>> bug (if warning is ignored at build time + on relevant arch)
> >>>>> goes
> >>>>> away
> >>>>> when JDK-8087120 gets backported to 8u.
> >>>>>
> >>>>> Original Bug: https://bugs.openjdk.java.net/browse/JDK-8087120
> >>>>> 9 webrev: http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8087
> >>>>> 120/
> >>>>> webrev.01/
> >>>>> 9 review thread: http://mail.openjdk.java.net/pipermail/hotspot
> >>>>> -dev
> >>>>> /2015-June/018884.html
> >>>>>
> >>>>> The 9 webrev applies with no change to the 8 forest. I'd need
> >>>>> somebody
> >>>>> to sponsor this for me.
> >>>>>
> >>>>> Thanks,
> >>>>> Severin
> >>>>>
> >>>
> >
> 

Built:

$ /mnt/builder/jdk8u-dev/images/j2sdk-image/bin/java  -version
openjdk version "1.8.0-internal"
OpenJDK Runtime Environment (build 1.8.0-internal-andre_2015_11_20_01_48-b00)
OpenJDK 64-Bit Zero VM (build 25.66-b00, interpreted mode)

with GCC 5.1.0 and pushed the change:

http://hg.openjdk.java.net/jdk8u/jdk8u-dev/hotspot/rev/c6ef40024aa2

An extra fix was needed to make it build, taken from 8075967:

diff -r c6ef40024aa2 src/cpu/zero/vm/frame_zero.cpp
--- a/src/cpu/zero/vm/frame_zero.cpp	Fri Jun 12 16:09:45 2015 +0100
+++ b/src/cpu/zero/vm/frame_zero.cpp	Fri Nov 20 03:17:01 2015 +0000
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2015, Oracle and/or its affiliates. All rights reserved.
  * Copyright 2007, 2008, 2009, 2010, 2011 Red Hat, Inc.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -216,7 +216,7 @@
     valuebuf[buflen - 1] = '\0';
 
     // Print the result
-    st->print_cr(" " PTR_FORMAT ": %-21s = %s", addr, fieldbuf, valuebuf);
+    st->print_cr(" " PTR_FORMAT ": %-21s = %s", p2i(addr), fieldbuf, valuebuf);
   }
 }

I don't know if 8075967 should be backported in full (it contains other changes,
and this seems to have been thrown in there to make it build):

8075967: Zero interpreter asserts for SafeFetch<32,N> calls in ObjectMonitor
Summary: Implement SafeFetchX unsafely and make CanUseSafeFetchX false for Zero
Reviewed-by: sgehwolf, dholmes

or we should backport just the above under a new bug ID. Thoughts?

Thanks,
-- 
Andrew :)

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

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