[m-rev.] for review: fix predicate_table_insert bug

[Fergus Henderson]

On 23-Oct-2003, Peter Ross <pro at missioncriticalit.com> wrote:
> 
> predicate_table_insert modifies the pred_info before inserting it into
> the pred_table, this "invalidates" the pred_info predicate_table_insert
> is called with however there are places in the compiler which use this
> invalid pred_info for further processing.
> 
> Fix this issue by no longer modifying the pred_info inside
> predicate_table_insert instead record the extra information in a new
> table.

That looks fine, thanks!

[It does lead to a slightly odd/inelegant data structure design,
where we have two different map(pred_id, ...) maps in the pred_table,
one mapping to pred_info and one mapping to the accessibility.
I probably would have been inclined to fix the bug differently,
by just finding all the places which call predicate_table_insert
and making sure that they do not rely on the pred_info remaining
unchanged, and adding some documentation to predicate_table_insert
to make it clear that it may modify the pred_info before inserting
it in the table, so the caller should not use the pred_info afterwards.
But your solution seems more robust.]

-- 
Fergus Henderson <fjh at cs.mu.oz.au>  |  "I have always known that the pursuit
The University of Melbourne         |  of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh>  |     -- the last words of T. S. Garp.
--------------------------------------------------------------------------
mercury-reviews mailing list
post:  mercury-reviews at cs.mu.oz.au
administrative address: owner-mercury-reviews at cs.mu.oz.au
unsubscribe: Address: mercury-reviews-request at cs.mu.oz.au Message: unsubscribe
subscribe:   Address: mercury-reviews-request at cs.mu.oz.au Message: subscribe
--------------------------------------------------------------------------