RFR: 8233364: Fix undefined behavior in Canonicalizer::do_ShiftOp

[Kim Barrett]

> On Nov 7, 2019, at 2:59 PM, Vladimir Kozlov <vladimir.kozlov at oracle.com> wrote:
> 
> Looks good.
> 
> thanks,
> Vladimir

Thanks.

> 
> On 11/7/19 11:49 AM, Kim Barrett wrote:
>> Ping.  Looking for a second review.
>>> On Nov 1, 2019, at 8:07 PM, Kim Barrett <kim.barrett at oracle.com> wrote:
>>> 
>>> Please review this change to Canonicalizer::do_ShiftOp to eliminate
>>> several actual or potential invocations of undefined behavior
>>> involving shift operations.  (See CR for details.)
>>> 
>>> To support this fix, a set of java_shift_xxx functions are added to
>>> globalDefinitions.hpp.  These use the same implementation techniques
>>> used by java_add and friends to perform the corresponding operation
>>> with Java semantics for handling overflows and such.
>>> 
>>> With these new java_shift_xxx functions available, the constant
>>> folding by do_ShiftOp is now trivially implemented by calls to those
>>> functions.
>>> 
>>> Added gtest-based unit tests covering the new shift functions.  Also
>>> added unit tests for java_add and friends, which should have been part
>>> of their addition by JDK-8145096.  (Oops!)
>>> 
>>> CR:
>>> https://bugs.openjdk.java.net/browse/JDK-8233364
>>> 
>>> Webrev:
>>> https://cr.openjdk.java.net/~kbarrett/8233364/open.00/
>>> 
>>> Testing:
>>> mach5 tier1-3.