On Sun, 20 Apr 2025, Dave Allured - NOAA Affiliate via macports-dev wrote:
On Sun, Apr 20, 2025 at 11:29 AM Joshua Root <[email protected]> wrote:
On 21/4/2025 01:27, Nils Breunese wrote:
I created a draft pull request to bump the openjdk11 port to version
11.0.27 (https://github.com/macports/macports-ports/pull/28212), but it
looks like this line:
AO_UNUSED_MBZ = (-1)<<13, // options bits reserved for future use.
in src/jdk.pack/share/native/common-unpack/constants.h results in this
error on macOS 15:
expression is not an integral constant expression
On macOS 13 and 14 the build succeeds without this error.
I am not too familiar with C++, but does this seem related to a change
in macOS 15? Any idea what should be done to fix the build on macOS 15?
It would be a compiler change rather than a change in the OS. I believe
using bitwise shift operators on a negative value has undefined
behaviour. The fix would be to express the constant in a well-defined
way, for example directly as a hex value, or by shifting a positive
value and then negating afterwards. I don't know how this constant is
used, so I can't say what would be most appropriate.
cppreference.com says that is undefined behavior. That constant is defined
as an enum, which I think means only that it needs to be a correctly
defined integer. Try something like this:
AO_UNUSED_MBZ = (~((1<<13) - 1))
No need to elaborately construct a two-complement negation when negation
was never the point in the first place. Just use:
AO_UNUSED_MBZ = ~0<<13, // options bits reserved for future use.
Or, for a more minimal textual change:
AO_UNUSED_MBZ = (~0)<<13, // options bits reserved for future use.
Though the parens were never necessary, since the unary operator takes
precedence over the shift.
Fred Wright
