RFR (S) 8031818: Experimental VM flag for enforcing safe object construction (original) (raw)

Vladimir Kozlov vladimir.kozlov at oracle.com
Wed Jan 22 00:07:07 PST 2014

On 1/21/14 9:10 PM, Vladimir Kozlov wrote:

May be we should use bitset enums to record types of stores to fields. Next changes touch the same C2 code:

http://hg.openjdk.java.net/ppc-aix-port/stage-9/hotspot/rev/c6d7e7406136 It uses method()->isinitializer() instead of (method()->name() == ciSymbol::objectinitializername()). The main problem that new flag check will be executed always. It will not be optimized by C++.

On other hand we already have experimental flags (for example, AggressiveUnboxing) so it is not big deal.

Vladimir

Regards, Vladimir On 1/21/14 2:47 PM, Aleksey Shipilev wrote: Hi,

Please review the experimental patch for switching the research VM mode which unconditionally emits the memory barrier at the end of constructor: http://cr.openjdk.java.net/~shade/8031818/webrev.00/ https://bugs.openjdk.java.net/browse/JDK-8031818 This would be convenient to have in mainline, because it will also propagate to another arch ports (notably PPC C2 port), and will ease the performance research for the upcoming JMM update. Thanks, -Aleksey.

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