From 65a00f30352a3c0ab5615fac008735b103cfa5bb Mon Sep 17 00:00:00 2001
From: Noah Misch <noah@leadboat.com>
Date: Fri, 8 Dec 2017 18:06:05 -0800
Subject: [PATCH] MSVC: Test whether 32-bit Perl needs -D_USE_32BIT_TIME_T.
Commits 5a5c2feca3fd858e70ea348822595547e6fa6c15 and
b5178c5d08ca59e30f9d9428fa6fdb2741794e65 introduced support for modern
MSVC-built, 32-bit Perl, but they broke use of MinGW-built, 32-bit Perl
distributions like Strawberry Perl and modern ActivePerl. Perl has no
robust means to report whether it expects a -D_USE_32BIT_TIME_T ABI, so
test this. Back-patch to 9.3 (all supported versions).
The chief alternative was a heuristic of adding -D_USE_32BIT_TIME_T when
$Config{gccversion} is nonempty. That banks on every gcc-built Perl
using the same ABI. gcc could change its default ABI the way MSVC once
did, and one could build Perl with gcc and the non-default ABI.
The GNU make build system could benefit from a similar test, without
which it does not support MSVC-built Perl. For now, just add a comment.
Most users taking the special step of building Perl with MSVC probably
build PostgreSQL with MSVC.
Discussion: https://postgr.es/m/20171130041441.GA3161526@rfd.leadboat.com
---
config/perl.m4 | 30 ++++---
src/tools/msvc/Mkvcbuild.pm | 170 ++++++++++++++++++++++++++++++------
2 files changed, 158 insertions(+), 42 deletions(-)
diff --git a/config/perl.m4 b/config/perl.m4
index 76b1a92e3a..caefb0705e 100644
--- a/config/perl.m4
+++ b/config/perl.m4
@@ -48,19 +48,23 @@ AC_DEFUN([PGAC_CHECK_PERL_CONFIGS],
# 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. 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.
+# We selectively extract stuff from $Config{ccflags}. 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. 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 most symbols that affect
+# Perl's own ABI begin with letters, so it's almost sufficient to adopt -D
+# switches for symbols not beginning with underscore. Some exceptions are the
+# Windows-specific -D_USE_32BIT_TIME_T and -D__MINGW_USE_VC2005_COMPAT; see
+# Mkvcbuild.pm for details. We absorb the former when Perl reports it. Perl
+# never reports the latter, and we don't attempt to deduce when it's needed.
+# Consequently, we don't support using MinGW to link to MSVC-built Perl. As
+# of 2017, all supported ActivePerl and Strawberry Perl are MinGW-built. If
+# that changes or an MSVC-built Perl distribution becomes prominent, we can
+# revisit this limitation.
AC_DEFUN([PGAC_CHECK_PERL_EMBED_CCFLAGS],
[AC_REQUIRE([PGAC_PATH_PERL])
AC_MSG_CHECKING([for CFLAGS recommended by Perl])
diff --git a/src/tools/msvc/Mkvcbuild.pm b/src/tools/msvc/Mkvcbuild.pm
index 4c2e12e228..93f364a9f2 100644
--- a/src/tools/msvc/Mkvcbuild.pm
+++ b/src/tools/msvc/Mkvcbuild.pm
@@ -28,6 +28,7 @@ my $libpgcommon;
my $libpgfeutils;
my $postgres;
my $libpq;
+my @unlink_on_exit;
# Set of variables for modules in contrib/ and src/test/modules/
my $contrib_defines = { 'refint' => 'REFINT_VERBOSE' };
@@ -517,34 +518,154 @@ sub mkvcbuild
my $plperl =
$solution->AddProject('plperl', 'dll', 'PLs', 'src/pl/plperl');
$plperl->AddIncludeDir($solution->{options}->{perl} . '/lib/CORE');
+ $plperl->AddReference($postgres);
+
+ my $perl_path = $solution->{options}->{perl} . '\lib\CORE\*perl*';
+
+ # ActivePerl 5.16 provided perl516.lib; 5.18 provided libperl518.a
+ my @perl_libs =
+ grep { /perl\d+\.lib$|libperl\d+\.a$/ } glob($perl_path);
+ if (@perl_libs == 1)
+ {
+ $plperl->AddLibrary($perl_libs[0]);
+ }
+ else
+ {
+ die
+"could not identify perl library version matching pattern $perl_path\n";
+ }
# 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[^_]/
- || $f =~ /^-D_USE_32BIT_TIME_T/)
+ if ($f =~ /^-D[^_]/)
{
$f =~ s/\-D//;
push(@perl_embed_ccflags, $f);
}
}
- # Perl versions before 5.13.4 don't provide -D_USE_32BIT_TIME_T
- # regardless of how they were built. On 32-bit Windows, assume
- # such a version was built with a pre-MSVC-2005 compiler, and
- # define the symbol anyway, so that we are compatible if we're
- # being built with a later MSVC version.
- push(@perl_embed_ccflags, '_USE_32BIT_TIME_T')
- if $solution->{platform} eq 'Win32'
- && $Config{PERL_REVISION} == 5
- && ($Config{PERL_VERSION} < 13
- || ( $Config{PERL_VERSION} == 13
- && $Config{PERL_SUBVERSION} < 4));
-
- # Also, a hack to prevent duplicate definitions of uid_t/gid_t
+ # hack to prevent duplicate definitions of uid_t/gid_t
push(@perl_embed_ccflags, 'PLPERL_HAVE_UID_GID');
+ # Windows offers several 32-bit ABIs. Perl is sensitive to
+ # sizeof(time_t), one of the ABI dimensions. To get 32-bit time_t,
+ # use "cl -D_USE_32BIT_TIME_T" or plain "gcc". For 64-bit time_t, use
+ # "gcc -D__MINGW_USE_VC2005_COMPAT" or plain "cl". Before MSVC 2005,
+ # plain "cl" chose 32-bit time_t. PostgreSQL doesn't support building
+ # with pre-MSVC-2005 compilers, but it does support linking to Perl
+ # built with such a compiler. MSVC-built Perl 5.13.4 and later report
+ # -D_USE_32BIT_TIME_T in $Config{ccflags} if applicable, but
+ # MinGW-built Perl never reports -D_USE_32BIT_TIME_T despite typically
+ # needing it. Ignore the $Config{ccflags} opinion about
+ # -D_USE_32BIT_TIME_T, and use a runtime test to deduce the ABI Perl
+ # expects. Specifically, test use of PL_modglobal, which maps to a
+ # PerlInterpreter field whose position depends on sizeof(time_t).
+ if ($solution->{platform} eq 'Win32')
+ {
+ my $source_file = 'conftest.c';
+ my $obj = 'conftest.obj';
+ my $exe = 'conftest.exe';
+ my @conftest = ($source_file, $obj, $exe);
+ push @unlink_on_exit, @conftest;
+ unlink $source_file;
+ open my $o, '>', $source_file
+ || croak "Could not write to $source_file";
+ print $o '
+ /* compare to plperl.h */
+ #define __inline__ __inline
+ #define PERL_NO_GET_CONTEXT
+ #include <EXTERN.h>
+ #include <perl.h>
+
+ int
+ main(int argc, char **argv)
+ {
+ int dummy_argc = 1;
+ char *dummy_argv[1] = {""};
+ char *dummy_env[1] = {NULL};
+ static PerlInterpreter *interp;
+
+ PERL_SYS_INIT3(&dummy_argc, (char ***) &dummy_argv,
+ (char ***) &dummy_env);
+ interp = perl_alloc();
+ perl_construct(interp);
+ {
+ dTHX;
+ const char key[] = "dummy";
+
+ PL_exit_flags |= PERL_EXIT_DESTRUCT_END;
+ hv_store(PL_modglobal, key, sizeof(key) - 1, newSViv(1), 0);
+ return hv_fetch(PL_modglobal, key, sizeof(key) - 1, 0) == NULL;
+ }
+ }
+';
+ close $o;
+
+ # Build $source_file with a given #define, and return a true value
+ # if a run of the resulting binary exits successfully.
+ my $try_define = sub {
+ my $define = shift;
+
+ unlink $obj, $exe;
+ my @cmd = (
+ 'cl',
+ '-I' . $solution->{options}->{perl} . '/lib/CORE',
+ (map { "-D$_" } @perl_embed_ccflags, $define || ()),
+ $source_file,
+ '/link',
+ $perl_libs[0]);
+ my $compile_output = `@cmd 2>&1`;
+ -f $exe || die "Failed to build Perl test:\n$compile_output";
+
+ {
+
+ # Some builds exhibit runtime failure through Perl warning
+ # 'Can't spawn "conftest.exe"'; supress that.
+ no warnings;
+
+ # Disable error dialog boxes like we do in the postmaster.
+ # Here, we run code that triggers relevant errors.
+ use Win32API::File qw(SetErrorMode :SEM_);
+ my $oldmode = SetErrorMode(
+ SEM_FAILCRITICALERRORS | SEM_NOGPFAULTERRORBOX);
+ system(".\\$exe");
+ SetErrorMode($oldmode);
+ }
+
+ return !($? >> 8);
+ };
+
+ my $define_32bit_time = '_USE_32BIT_TIME_T';
+ my $ok_now = $try_define->(undef);
+ my $ok_32bit = $try_define->($define_32bit_time);
+ unlink @conftest;
+ if (!$ok_now && !$ok_32bit)
+ {
+
+ # Unsupported configuration. Since we used %Config from the
+ # Perl running the build scripts, this is expected if
+ # attempting to link with some other Perl.
+ die "Perl test fails with or without -D$define_32bit_time";
+ }
+ elsif ($ok_now && $ok_32bit)
+ {
+
+ # Resulting build may work, but it's especially important to
+ # verify with "vcregress plcheck". A refined test may avoid
+ # this outcome.
+ warn "Perl test passes with or without -D$define_32bit_time";
+ }
+ elsif ($ok_32bit)
+ {
+ push(@perl_embed_ccflags, $define_32bit_time);
+ } # else $ok_now, hence no flag required
+ }
+
+ print "CFLAGS recommended by Perl: $Config{ccflags}\n";
+ print "CFLAGS to compile embedded Perl: ",
+ (join ' ', map { "-D$_" } @perl_embed_ccflags), "\n";
foreach my $f (@perl_embed_ccflags)
{
$plperl->AddDefine($f);
@@ -614,20 +735,6 @@ sub mkvcbuild
die 'Failed to create plperl_opmask.h' . "\n";
}
}
- $plperl->AddReference($postgres);
- my $perl_path = $solution->{options}->{perl} . '\lib\CORE\*perl*';
- # ActivePerl 5.16 provided perl516.lib; 5.18 provided libperl518.a
- my @perl_libs =
- grep { /perl\d+\.lib$|libperl\d+\.a$/ } glob($perl_path);
- if (@perl_libs == 1)
- {
- $plperl->AddLibrary($perl_libs[0]);
- }
- else
- {
- die
-"could not identify perl library version matching pattern $perl_path\n";
- }
# Add transform module dependent on plperl
my $hstore_plperl = AddTransformModule(
@@ -956,4 +1063,9 @@ sub AdjustModule
}
}
+END
+{
+ unlink @unlink_on_exit;
+}
+
1;