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

Kim Barrett kim.barrett at oracle.com
Sat Nov 2 00:07:11 UTC 2019

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

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!)



mach5 tier1-3.

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