bebe174bb4
In Perl builds that define PERL_IMPLICIT_SYS, XSUB.h defines macros that replace a whole lot of basic libc functions with Perl functions. We can't tolerate that in plperl.c; it breaks at least PG_TRY and probably other stuff. The core idea of this patch is to include XSUB.h only in the .xs files where it's really needed, and to move any code broken by PERL_IMPLICIT_SYS out of the .xs files and into plperl.c. The reason this hasn't been a problem before is that our build techniques did not result in PERL_IMPLICIT_SYS appearing as a #define in PL/Perl, even on some platforms where Perl thinks it is defined. That's about to change in order to fix a nasty portability issue, so we need this work to make the code safe for that. Rather unaccountably, the Perl people chose XSUB.h as the place to provide the versions of the aTHX/aTHX_ macros that are needed by code that's not explicitly aware of the MULTIPLICITY API conventions. Hence, just removing XSUB.h from plperl.c fails miserably. But we can work around that by defining PERL_NO_GET_CONTEXT (which would make the relevant stanza of XSUB.h a no-op anyway). As explained in perlguts.pod, that means we need to add a "dTHX" macro call in every C function that calls a Perl API function. In most of them we just add this at the top; but since the macro fetches the current Perl interpreter pointer, more care is needed in functions that switch the active interpreter. Lack of the macro is easily recognized since it results in bleats about "my_perl" not being defined. (A nice side benefit of this is that it significantly reduces the number of fetches of the current interpreter pointer. On my machine, plperl.so gets more than 10% smaller, and there's probably some performance win too. We could reduce the number of fetches still more by decorating the code with pTHX_/aTHX_ macros to pass the interpreter pointer around, as explained by perlguts.pod; but that's a task for another day.) Formatting note: pgindent seems happy to treat "dTHX;" as a declaration so long as it's the first thing after the left brace, as we'd already observed with respect to the similar macro "dSP;". If you try to put it later in a set of declarations, pgindent puts ugly extra space around it. Having removed XSUB.h from plperl.c, we need only move the support functions for spi_return_next and util_elog (both of which use PG_TRY) out of the .xs files and into plperl.c. This seems sufficient to avoid the known problems caused by PERL_IMPLICIT_SYS, although we could move more code if additional issues emerge. This will need to be back-patched, but first let's see what the buildfarm makes of it. Patch by me, with some help from Ashutosh Sharma Discussion: https://postgr.es/m/CANFyU97OVQ3+Mzfmt3MhuUm5NwPU=-FtbNH5Eb7nZL9ua8=rcA@mail.gmail.com |
||
|---|---|---|
| config | ||
| contrib | ||
| doc | ||
| src | ||
| .dir-locals.el | ||
| .gitattributes | ||
| .gitignore | ||
| COPYRIGHT | ||
| GNUmakefile.in | ||
| HISTORY | ||
| Makefile | ||
| README | ||
| README.git | ||
| aclocal.m4 | ||
| configure | ||
| configure.in | ||
README
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. PostgreSQL has many language interfaces, many of which are listed here: https://www.postgresql.org/download See the file INSTALL for instructions on how to build and install PostgreSQL. That file also lists supported operating systems and hardware platforms and contains information regarding any other software packages that are required to build or run the PostgreSQL system. Copyright and license information can be found in the file COPYRIGHT. A comprehensive documentation set is included in this distribution; it can be read as described in the installation instructions. The latest version of this software may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.