RFR(S): 8050978: Fix bad field access check in C1 and C2

[Lindenmaier, Goetz]

Hi Vladimir, 

we updated the changeset with the new comment. 
http://cr.openjdk.java.net/~goetz/webrevs/8050978-fieldCheck/webrev-01/

Best regards,
  Goetz.

-----Original Message-----
From: Vladimir Kozlov [mailto:vladimir.kozlov at oracle.com] 
Sent: Donnerstag, 17. Juli 2014 18:02
To: hotspot-dev at openjdk.java.net
Subject: Re: RFR(S): 8050978: Fix bad field access check in C1 and C2

Please, don't put next part of comment into sources:

+  // This will make the jck8 test
+  // vm/constantpool/accessControl/accessControl004/accessControl00402m3/accessControl00402m3.html
+  // pass with -Xbatch -Xcomp

instead add something like "canonical_holder should not be use to check access becasue it can erroneously succeeds".

Thanks,
Vladimir

On 7/17/14 3:47 AM, Lindenmaier, Goetz wrote:
> Hi,
>
> This fixes an error doing field access checks in C1 and C2.
> Please review and test the change.  We please need a sponsor.
> http://cr.openjdk.java.net/~goetz/webrevs/8050978-fieldCheck/webrev-01/
>
> This should be included in 8u20, too.
>
> JCK8 test vm/constantpool/accessControl/accessControl004/accessControl00402m3/accessControl00402m3.html fails with -Xbatch -Xcomp due to bad field access check in C1 and C2
>
> Precondition:
> -------------
>
> Consider the following class hierarchy:
>
>      A
>    / \
>   B1 B2
>
> A declares a field "aa" which both B1 and B2 inherit.
>
> Despite aa is declared in a super class of B1, methods in B1 might not access the field aa of an object of class B2:
>
> class B1 extends A {
>    m(B2 b2) {
>      ...
>      x = b2.aa; // !!! Access not allowed
>    }
> }
>
> This is checked by the test mentioned above.
>
> Problem:
> --------
>
> ciField::will_link() used by C1 and C2 does the access check using the canonical_holder (which is A in this case) and thus the access erroneously succeeds.
>
> Fix:
> ----
>
> In ciField::ciField(), just before the canonical holder is stored into the _holder variable (and which is used by ciField::will_link()) perform an additional access check with the holder declared in the class file. If this check fails, store the declared holder instead and ciField::will_link() will bail out compilation for this field later on. Then, the interpreter will throw an PrivilegedAccessException at runtime.
>
> Ways to reproduce:
> ------------------
>
> Run the above JCK test with
>
> C2 only: -XX:-TieredCompilation -Xbatch -Xcomp
>
> or
>
> with C1: -Xbatch -Xcomp -XX:-Inline
>
> Best regards,
>    Andreas and Goetz
>
>