8191937082
Late-model gcc with -fsanitize=undefined enabled issues warnings about uses of PageGetItemId() when it can't prove that the offsetNumber is > 0. The call sites where this happens are checking that the offnum is <= PageGetMaxOffsetNumber(page), so it seems reasonable to add an explicit check that offnum >= 1 too. While at it, rearrange the code to be less contorted and avoid duplicate checks on PageGetMaxOffsetNumber. Maybe the compiler would optimize away the duplicate logic or maybe not, but the existing coding has little to recommend it anyway. There are multiple instances of this identical coding pattern in heapam.c and heapam_xlog.c. Current gcc only complains about two of them, but I fixed them all in the name of consistency. Potentially this could be back-patched in the name of silencing warnings; but I think enabling UBSAN is mainly something people would do on HEAD, so for now it seems not worth the trouble. Discussion: https://postgr.es/m/1699806.1765746897@sss.pgh.pa.us
PostgreSQL Database Management System
This directory contains the source code distribution of the PostgreSQL database management system.
PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/installation.html.
The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.