PL/Perl portability fix: absorb relevant -D switches from Perl.

The Perl documentation is very clear that stuff calling libperl should
be built with the compiler switches shown by Perl's $Config{ccflags}.
We'd been ignoring that up to now, and mostly getting away with it,
but recent Perl versions contain ABI compatibility cross-checks that
fail on some builds because of this omission.  In particular the
sizeof(PerlInterpreter) can come out different due to some fields being
added or removed; which means we have a live ABI hazard that we'd better
fix rather than continuing to sweep it under the rug.

However, it still seems like a bad idea to just absorb $Config{ccflags}
verbatim.  In some environments Perl was built with a different compiler
that doesn't even use the same switch syntax.  -D switch syntax is pretty
universal though, and absorbing Perl's -D switches really ought to be
enough to fix the problem.

Furthermore, Perl likes to inject stuff like -D_LARGEFILE_SOURCE and
-D_FILE_OFFSET_BITS=64 into $Config{ccflags}, which affect libc ABIs on
platforms where they're relevant.  Adopting those seems dangerous too.
It's unclear whether a build wherein Perl and Postgres have different ideas
of sizeof(off_t) etc would work, or whether anyone would care about making
it work.  But it's dead certain that having different stdio ABIs in
core Postgres and PL/Perl will not work; we've seen that movie before.
Therefore, let's also ignore -D switches for symbols beginning with
underscore.  The symbols that we actually need to import should be the ones
mentioned in perl.h's PL_bincompat_options stanza, and none of those start
with underscore, so this seems likely to work.  (If it turns out not to
work everywhere, we could consider intersecting the symbols mentioned in
PL_bincompat_options with the -D switches.  But that will be much more
complicated, so let's try this way first.)

This will need to be back-patched, but first let's see what the
buildfarm makes of it.

Ashutosh Sharma, some adjustments by me

Discussion: https://postgr.es/m/CANFyU97OVQ3+Mzfmt3MhuUm5NwPU=-FtbNH5Eb7nZL9ua8=rcA@mail.gmail.com

diff --git a/config/perl.m4 b/config/perl.m4
index bed2eae57fe21af61dd764408ae3c038eee7fa16..9706c4de6aca951b9187c0b3f689faf581084ddf 100644 (file)
--- a/config/perl.m4
+++ b/config/perl.m4
@@ -49,6 +49,31 @@ AC_DEFUN([PGAC_CHECK_PERL_CONFIGS],
 [m4_foreach([pgac_item], [$1], [PGAC_CHECK_PERL_CONFIG(pgac_item)])])
 
 
+# PGAC_CHECK_PERL_EMBED_CCFLAGS
+# -----------------------------
+# We selectively extract stuff from $Config{ccflags}.  We don't really need
+# anything except -D switches, and other sorts of compiler switches can
+# actively break things if Perl was compiled with a different compiler.
+# Moreover, although Perl likes to put stuff like -D_LARGEFILE_SOURCE and
+# -D_FILE_OFFSET_BITS=64 here, it would be fatal to try to compile PL/Perl
+# to a different libc ABI than core Postgres uses.  The available information
+# says that all the symbols that affect Perl's own ABI begin with letters,
+# so it should be sufficient to adopt -D switches for symbols not beginning
+# with underscore.
+# For debugging purposes, let's have the configure output report the raw
+# ccflags value as well as the set of flags we chose to adopt.
+AC_DEFUN([PGAC_CHECK_PERL_EMBED_CCFLAGS],
+[AC_REQUIRE([PGAC_PATH_PERL])
+AC_MSG_CHECKING([for CFLAGS recommended by Perl])
+perl_ccflags=`$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[^_]/)}']`
+AC_SUBST(perl_embed_ccflags)dnl
+AC_MSG_RESULT([$perl_embed_ccflags])
+])# PGAC_CHECK_PERL_EMBED_CCFLAGS
+
+
 # PGAC_CHECK_PERL_EMBED_LDFLAGS
 # -----------------------------
 # We are after Embed's ldopts, but without the subset mentioned in

diff --git a/configure b/configure
index aff72eb00866f0ffab899c227ac612271297a87d..a16e4f42d8d71a9dcf68a0fa0117bed792aef461 100755 (executable)
--- a/configure
+++ b/configure
@@ -668,6 +668,7 @@ python_version
 python_majorversion
 PYTHON
 perl_embed_ldflags
+perl_embed_ccflags
 perl_useshrplib
 perl_privlibexp
 perl_archlibexp
@@ -7767,6 +7768,18 @@ documentation for details.  Use --without-perl to disable building
 PL/Perl." "$LINENO" 5
   fi
 
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for CFLAGS recommended by Perl" >&5
+$as_echo_n "checking for CFLAGS recommended by Perl... " >&6; }
+perl_ccflags=`$PERL -MConfig -e 'print $Config{ccflags}'`
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $perl_ccflags" >&5
+$as_echo "$perl_ccflags" >&6; }
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for CFLAGS to compile embedded Perl" >&5
+$as_echo_n "checking for CFLAGS to compile embedded Perl... " >&6; }
+perl_embed_ccflags=`$PERL -MConfig -e 'foreach $f (split(" ",$Config{ccflags})) {print $f, " " if ($f =~ /^-D[^_]/)}'`
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $perl_embed_ccflags" >&5
+$as_echo "$perl_embed_ccflags" >&6; }
+
+
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for flags to link embedded Perl" >&5
 $as_echo_n "checking for flags to link embedded Perl... " >&6; }
 if test "$PORTNAME" = "win32" ; then

diff --git a/configure.in b/configure.in
index 72e5b17ea747afe52cafc0327414ed36bffbcba0..13c69d6fbdb3a1b290ebe6d8d47478324d6bb1ef 100644 (file)
--- a/configure.in
+++ b/configure.in
@@ -938,6 +938,7 @@ You might have to rebuild your Perl installation.  Refer to the
 documentation for details.  Use --without-perl to disable building
 PL/Perl.])
   fi
+  PGAC_CHECK_PERL_EMBED_CCFLAGS
   PGAC_CHECK_PERL_EMBED_LDFLAGS
 fi
 

diff --git a/contrib/hstore_plperl/Makefile b/contrib/hstore_plperl/Makefile
index 34e1e137f7132a08ff09313969fc52644aa876bb..c0906db1f55144940c95d53dceda635bcade7a40 100644 (file)
--- a/contrib/hstore_plperl/Makefile
+++ b/contrib/hstore_plperl/Makefile
@@ -38,4 +38,4 @@ endif
 # last, probably because it sometimes contains some header files with names
 # that clash with some of ours, or with some that we include, notably on
 # Windows.
-override CPPFLAGS := $(CPPFLAGS) -I$(perl_archlibexp)/CORE
+override CPPFLAGS := $(CPPFLAGS) $(perl_embed_ccflags) -I$(perl_archlibexp)/CORE

diff --git a/src/Makefile.global.in b/src/Makefile.global.in
index dc8a89af8e229ef25d1cefc17c31afae22140270..0d3f8ca9504b6d1b4934ceb9bcd5fe8d6817f1e0 100644 (file)
--- a/src/Makefile.global.in
+++ b/src/Makefile.global.in
@@ -304,6 +304,7 @@ else
 endif
 perl_archlibexp                = @perl_archlibexp@
 perl_privlibexp                = @perl_privlibexp@
+perl_embed_ccflags     = @perl_embed_ccflags@
 perl_embed_ldflags     = @perl_embed_ldflags@
 
 # Miscellaneous

diff --git a/src/pl/plperl/GNUmakefile b/src/pl/plperl/GNUmakefile
index b8e3585254426a1c5794e15c473e6fe2cdadfb7d..191f74067a6583b4ab75ccc68312fc873d42dd2f 100644 (file)
--- a/src/pl/plperl/GNUmakefile
+++ b/src/pl/plperl/GNUmakefile
@@ -12,7 +12,11 @@ override CPPFLAGS += -DPLPERL_HAVE_UID_GID
 override CPPFLAGS += -Wno-comment
 endif
 
-override CPPFLAGS := -I. -I$(srcdir) $(CPPFLAGS) -I$(perl_archlibexp)/CORE
+# Note: we need to make sure that the CORE directory is included last,
+# probably because it sometimes contains some header files with names
+# that clash with some of ours, or with some that we include, notably on
+# Windows.
+override CPPFLAGS := -I. -I$(srcdir) $(CPPFLAGS) $(perl_embed_ccflags) -I$(perl_archlibexp)/CORE
 
 rpathdir = $(perl_archlibexp)/CORE
 

diff --git a/src/tools/msvc/Mkvcbuild.pm b/src/tools/msvc/Mkvcbuild.pm
index e0bf60797f70123f144b31304847e4af914be0c3..a7e3a014d7a7a6b08e65f42215f3ec8cb32a4c69 100644 (file)
--- a/src/tools/msvc/Mkvcbuild.pm
+++ b/src/tools/msvc/Mkvcbuild.pm
@@ -517,7 +517,26 @@ sub mkvcbuild
                my $plperl =
                  $solution->AddProject('plperl', 'dll', 'PLs', 'src/pl/plperl');
                $plperl->AddIncludeDir($solution->{options}->{perl} . '/lib/CORE');
-               $plperl->AddDefine('PLPERL_HAVE_UID_GID');
+
+               # Add defines from Perl's ccflags; see PGAC_CHECK_PERL_EMBED_CCFLAGS
+               my @perl_embed_ccflags;
+               foreach my $f (split(" ",$Config{ccflags}))
+               {
+                       if ($f =~ /^-D[^_]/)
+                       {
+                               $f =~ s/\-D//;
+                               push(@perl_embed_ccflags, $f);
+                       }
+               }
+
+               # XXX this probably is redundant now?
+               push(@perl_embed_ccflags, 'PLPERL_HAVE_UID_GID');
+
+               foreach my $f (@perl_embed_ccflags)
+               {
+                       $plperl->AddDefine($f);
+               }
+
                foreach my $xs ('SPI.xs', 'Util.xs')
                {
                        (my $xsc = $xs) =~ s/\.xs/.c/;
@@ -601,7 +620,11 @@ sub mkvcbuild
                        'hstore_plperl', 'contrib/hstore_plperl',
                        'plperl',        'src/pl/plperl',
                        'hstore',        'contrib/hstore');
-               $hstore_plperl->AddDefine('PLPERL_HAVE_UID_GID');
+
+               foreach my $f (@perl_embed_ccflags)
+               {
+                       $hstore_plperl->AddDefine($f);
+               }
        }
 
        $mf =