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Absorb -D_USE_32BIT_TIME_T switch from Perl, if relevant.

Commit 3c163a7fc's original choice to ignore all #define symbols whose
names begin with underscore turns out to be too simplistic.  On Windows,
some Perl installations are built with -D_USE_32BIT_TIME_T, and we must
absorb that or we get the wrong result for sizeof(PerlInterpreter).

This effectively re-reverts commit ef58b87df, which injected that symbol
in a hacky way, making it apply to all of Postgres not just PL/Perl.
More significantly, it did so on *all* 32-bit Windows builds, even when
the Perl build to be used did not select this option; so that it fails
to work properly with some newer Perl builds.

By making this change, we would be introducing an ABI break in 32-bit
Windows builds; but fortunately we have not used type time_t in any
exported Postgres APIs in a long time.  So it should be OK, both for
PL/Perl itself and for third-party extensions, if an extension library
is built with a different _USE_32BIT_TIME_T setting than the core code.

Patch by me, based on research by Ashutosh Sharma and Robert Haas.
Back-patch to all supported branches, as commit 3c163a7fc was.

Discussion: https://postgr.es/m/CANFyU97OVQ3+Mzfmt3MhuUm5NwPU=-FtbNH5Eb7nZL9ua8=rcA@mail.gmail.com
This commit is contained in:
Tom Lane
2017-08-14 11:48:59 -04:00
parent ea0ca75d5d
commit 5a5c2feca3
5 changed files with 12 additions and 20 deletions

View File

@ -56,7 +56,9 @@ AC_DEFUN([PGAC_CHECK_PERL_CONFIGS],
# to a different libc ABI than core Postgres uses. The available information
# says that all the symbols that affect Perl's own ABI begin with letters,
# so it should be sufficient to adopt -D switches for symbols not beginning
# with underscore.
# with underscore. An exception is that we need to let through
# -D_USE_32BIT_TIME_T if it's present. (We probably could restrict that to
# only get through on Windows, but for the moment we let it through always.)
# For debugging purposes, let's have the configure output report the raw
# ccflags value as well as the set of flags we chose to adopt.
AC_DEFUN([PGAC_CHECK_PERL_EMBED_CCFLAGS],
@ -65,7 +67,7 @@ AC_MSG_CHECKING([for CFLAGS recommended by Perl])
perl_ccflags=`$PERL -MConfig -e ['print $Config{ccflags}']`
AC_MSG_RESULT([$perl_ccflags])
AC_MSG_CHECKING([for CFLAGS to compile embedded Perl])
perl_embed_ccflags=`$PERL -MConfig -e ['foreach $f (split(" ",$Config{ccflags})) {print $f, " " if ($f =~ /^-D[^_]/)}']`
perl_embed_ccflags=`$PERL -MConfig -e ['foreach $f (split(" ",$Config{ccflags})) {print $f, " " if ($f =~ /^-D[^_]/ || $f =~ /^-D_USE_32BIT_TIME_T/)}']`
AC_SUBST(perl_embed_ccflags)dnl
AC_MSG_RESULT([$perl_embed_ccflags])
])# PGAC_CHECK_PERL_EMBED_CCFLAGS