Re: Convert *GetDatum() and DatumGet*() macros to inline functions

Peter Eisentraut <peter(dot)eisentraut(at)enterprisedb(dot)com> writes:
>> Ok, it has problems with 32-bit platforms.  I can reproduce it locally.
>> I'll need to take another look at this.  I have reverted the patch for now.

> I have tried to analyze these issues, but I'm quite stuck. If anyone
> else has any ideas, it would be helpful.

It looks to me like the problem is with the rewrite of Int64GetDatumFast
and Float8GetDatumFast:

+static inline Datum
+Int64GetDatumFast(int64 X)
+{
+#ifdef USE_FLOAT8_BYVAL
+ return Int64GetDatum(X);
+#else
+ return PointerGetDatum(&X);
+#endif
+}

In the by-ref code path, this is going to return the address of the
parameter local variable, which of course is broken as soon as the
function exits. To test, I reverted the mods to those two macros,
and I got through check-world OK in a 32-bit VM.

I think we can do this while still having reasonable type-safety
by adding AssertVariableIsOfTypeMacro() checks to the macros.
An advantage of that solution is that we verify that the code
will be safe for a 32-bit build even in 64-bit builds. (Of
course, it's just checking the variable's type not its lifespan,
but this is still a step forward.)

0001 attached is what you committed, 0002 is a proposed delta
to fix the Fast macros.

regards, tom lane