On Mon, 2012-09-03 at 11:14 +0100, Peter Geoghegan wrote:
> Come to think of it, the whole convention of using a lower-case
> variant of the original pointer variable name seems like a foot-gun,
> given the harmful and indeed very subtle consequences of making this
> error.
With some inventive macro magic, you could probably make this safer.
I'm thinking something along the lines of replacing
SpinLockAcquire(&xlogctl->info_lck);
with
SpinLockAcquire(XLogCtl, info_lck);
which expands to
{
volatile typeof(XLogCtl) *XLogCtl_volatile = XLogCtl;
void *XLogCtl = NULL; // compiler error or crash at run time if used
OldSpinLockAcquire(XLogCtl_volatile->info_lock);
...
and then something corresponding for SpinLockRelease.
This will likely only work with modern compilers, but it could give you
some amount of static checking against this problem.
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