Add additional check for custom array/hash access checking #23399
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PL_check[] can have customized checks for array/hash elements in the OP_AELEM, OP_EXISTS, and OP_DELETE elements. When these are set, the multideref optimization is turned off. It turns out that checking for this always shows that they are not the standard values on z/OS, because that platform's function pointers may point to a "function descriptor" and not the actual function, or it may not. It's not clear to me if this implementation conforms to the C Standard or not, but it is what it is. As a result our test suite fails some tests that are expecting non-custom entries in those slots. This commit builds upon some ideas from Dave Mitchell and Richard Leach to add 3 entries to the array of function pointers. These entries are initialized the same way the others are, so that a comparison against them when no customization has been done should succeed. The current comparisons are retained, so that it's likely on z/OS one or the other will succeed when no customization is currently in place.
I imagine most compilers would know to optimize the reference away when the first conditional has ruled out all but one possibility, but I think it is clearer anyway to use that single value.
It's also unlikely that the op_type will be any given value, but I expect the compiler and libc know that. This stresses that it is unlikely some module will customize the handling of these checkers.
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PL_check[] can have customized checks for array/hash elements in the
OP_AELEM, OP_EXISTS, and OP_DELETE elements. When these are set, the
multideref optimization is turned off.
It turns out that checking for this always shows that they are not the
standard values on z/OS, because that platform's function pointers may
point to a "function descriptor" and not the actual function, or it may
not. It's not clear to me if this implementation conforms to the C
Standard or not, but it is what it is. As a result our test suite fails
some tests that are expecting non-custom entries in those slots.
This commit builds upon some ideas from Dave Mitchell and Richard Leach
to add 3 entries to the array of function pointers. These entries are
initialized the same way the others are, so that a comparison against
them when no customization has been done should succeed.
The current comparisons are retained, so that it's likely on z/OS one or
the other will succeed when no customization is currently in place.