RFR(XS) 8087120: [GCC5] java.lang.StackOverflowError on Zero JVM initialization on non x86 platforms (original) (raw)

David Holmes david.holmes at oracle.com
Thu Jun 11 10:51:34 UTC 2015

Hi Severin,

On 11/06/2015 6:05 PM, Severin Gehwolf wrote:

Hi David,

On Thu, 2015-06-11 at 15:45 +1000, David Holmes wrote: On 10/06/2015 11:49 PM, Severin Gehwolf wrote:

Hi,

Could somebody please review this Zero only change? I'd also need a sponsor who can push the change for me once reviewed. Bug: https://bugs.openjdk.java.net/browse/JDK-8087120 webrev: http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8087120/webrev.01/ The issue is that Zero relies on undefined behaviour for getting the current stack pointer by allocating a variable on the stack and returning its address. With GCC 5 returning an address of a local variable will always be 0, thus causing the issue. It worked fine with older GCC versions, because they returned the actual address of the variable. _The fix is to use GCC's built-in function "builtinframeaddress". This also works on GCC 5. It's GCC specific, though. On the other hand, I don't know if anybody builds Zero without GCC. An alternative would be to use alloca, but that has strange semantics if the stack pointer cannot be extended. Thoughts? The Zero folk will need to confirm if this gcc dependency is ok or whether it requires an ifdef - and they can also push directly to one of the hotspot repos. Speaking as the Zero maintainer, the GCC dependency is OK. I'd rather avoid the ifdef. Unfortunately, I am not a committer so cannot push it myself. I can ask Andrew Haley to push the fix for me once you're OK with it.

It is zero specific so I am fine with it if you are.

Thanks, David

Is the built-in available across gcc 4.x releases? Looking at the oldest GCC manual I've found for the 4.x series it appears it's available since 4.0.4. A couple of examples: https://gcc.gnu.org/onlinedocs/gcc-4.0.4/gcc/Return-Address.html#Return-Address https://gcc.gnu.org/onlinedocs/gcc-4.1.2/gcc/Return-Address.html#Return-Address https://gcc.gnu.org/onlinedocs/gcc-4.5.4/gcc/Return-Address.html#Return-Address https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/Return-Address.html#Return-Address https://gcc.gnu.org/onlinedocs/gcc-5.1.0/gcc/Return-Address.html#Return-Address Thanks, Severin

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