AIX: Implement shared_target = "aix-solib" support

This builds shared libraries as libxxx.so, libxxx.so.ver and static
libraries as libxxx.a.  For shlib_variant builds, it builds libxxx.so,
libxxxvariant.so.ver, and libxxxx.a.  libxxx.so is a linker import
library that directs the linker to embed a run-time dependency
reference to libxxxvariant.so.ver.  Only libxxxvariant.so.ver is needed
at runtime.

Fixes #21518

Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/21540)

Configurations/10-main.conf

@@ -1407,6 +1407,19 @@ my %targets = (
         AR               => add("-X32"),
         RANLIB           => add("-X32"),
     },
+    # shared_target of "aix-solib" builds shared libraries packaged
+    # without archives.  This improves the behavior of inter-library
+    # references (libssl depending on libcrypto) when building with
+    # shlib_variant.
+    # You'll get:  libxxx.so (import library, used when linking applications)
+    #              libxxx.so.ver (shared object)
+    #              libxxx.a (static library archive)
+    # and for runtime, you only need libxxx.so.ver.  libxxx.so and libxxx.a
+    # can be installed along with include files to make an SDK
+    "aix-cc-solib" => {
+        inherit_from     => [ "aix-cc" ],
+        shared_target    => "aix-solib",
+    },
     "aix64-cc" => {
         inherit_from     => [ "aix-common" ],
         CC               => "cc",
@@ -1425,6 +1438,10 @@ my %targets = (
         AR               => add("-X64"),
         RANLIB           => add("-X64"),
     },
+    "aix64-cc-solib" => {
+        inherit_from     => [ "aix64-cc" ],
+        shared_target    => "aix-solib",
+    },
 
 # SIEMENS BS2000/OSD: an EBCDIC-based mainframe
     "BS2000-OSD" => {

Configurations/platform/AIX.pm

@@ -13,12 +13,16 @@ require platform::Unix;
 use configdata;
 
 sub dsoext              { '.so' }
-sub shlibextsimple      { '.a' }
+sub shlibextsimple      { return '.so' if $target{shared_target} eq "aix-solib";
+			  '.a'}
 
 # In shared mode, the default static library names clashes with the final
 # "simple" full shared library name, so we add '_a' to the basename of the
-# static libraries in that case.
+# static libraries in that case, unless in solib mode (using only .so
+# files for shared libraries, and not packaging them inside archives)
 sub staticname {
+    return platform::Unix->staticname($_[1]) if $target{shared_target} eq "aix-solib";
+
     # Non-installed libraries are *always* static, and their names remain
     # the same, except for the mandatory extension
     my $in_libname = platform::BASE->staticname($_[1]);
@@ -27,3 +31,17 @@ sub staticname {
 
     return platform::BASE->staticname($_[1]) . ($disabled{shared} ? '' : '_a');
 }
+
+# In solib mode, we do not install the simple symlink (we install the import
+# library).  In regular mode, we install the symlink.
+sub sharedlib_simple {
+    return undef if $target{shared_target} eq "aix-solib";
+    return platform::Unix->sharedlib_simple($_[1], $_[0]->shlibextsimple());
+}
+
+# In solib mode, we install the import library.  In regular mode, we have
+# no import library.
+sub sharedlib_import {
+    return platform::Unix->sharedlib_simple($_[1]) if $target{shared_target} eq "aix-solib";
+    return undef;
+}

Configurations/platform/Unix.pm

@@ -73,7 +73,9 @@ sub sharedlib_simple {
     my $name = $_[0]->sharedname($_[1]);
     my $simplename = $_[0]->sharedname_simple($_[1]);
     my $ext = $_[0]->shlibext();
-    my $simpleext = $_[0]->shlibextsimple();
+    # Allow override of the extension passed in as parameter
+    my $simpleext = $_[2];
+    $simpleext = $_[0]->shlibextsimple() unless defined $simpleext;
 
     return undef unless defined $simplename && defined $name;
     return undef if ($name eq $simplename && $ext eq $simpleext);

Configurations/unix-Makefile.tmpl

@@ -11,8 +11,13 @@
      sub windowsdll { $config{target} =~ /^(?:Cygwin|mingw)/ }
 
      # Shared AIX support is special. We put libcrypto[64].so.ver into
-     # libcrypto.a and use libcrypto_a.a as static one.
-     sub sharedaix  { !$disabled{shared} && $config{target} =~ /^aix/ }
+     # libcrypto.a and use libcrypto_a.a as static one, unless using
+     # shared_target style aix-solib.  In that mode, create
+     # libcrypto.so as a link-import library that inserts runtime
+     # dependencies on libcrypto.so.ver, and the static library is
+     # named libcrypto.a.
+     sub sharedaix  { !$disabled{shared} && $target{shared_target} =~ /^aix(?!-solib$)/ }
+     sub sharedaix_solib  { !$disabled{shared} && $target{shared_target} =~ /^aix-solib$/ }
 
      our $sover_dirname = platform->shlib_version_as_filename();
 
@@ -760,12 +765,12 @@ install_dev: install_runtime_libs
 		fn1=`basename "$$s1"`; \
 		fn2=`basename "$$s2"`; \
 		fn3=`basename "$$s3"`; \
-		: {- output_off(); output_on() unless windowsdll() or sharedaix(); "" -}; \
+		: {- output_off(); output_on() unless windowsdll() or sharedaix() or sharedaix_solib(); "" -}; \
 		if [ "$$fn2" != "" ]; then \
 			$(ECHO) "link $(DESTDIR)$(libdir)/$$fn2 -> $(DESTDIR)$(libdir)/$$fn1"; \
 			ln -sf $$fn1 "$(DESTDIR)$(libdir)/$$fn2"; \
 		fi; \
-		: {- output_off() unless windowsdll() or sharedaix(); output_on() if windowsdll(); "" -}; \
+		: {- output_off() unless windowsdll() or sharedaix() or sharedaix_solib(); output_on() if windowsdll() or sharedaix_solib(); "" -}; \
 		if [ "$$fn3" != "" ]; then \
 			$(ECHO) "install $$s3 -> $(DESTDIR)$(libdir)/$$fn3"; \
 			cp $$s3 "$(DESTDIR)$(libdir)/$$fn3.new"; \
@@ -773,7 +778,7 @@ install_dev: install_runtime_libs
 			mv -f "$(DESTDIR)$(libdir)/$$fn3.new" \
 			      "$(DESTDIR)$(libdir)/$$fn3"; \
 		fi; \
-		: {- output_off() if windowsdll(); output_on() if sharedaix(); "" -}; \
+		: {- output_off() if windowsdll() or sharedaix_solib(); output_on() if sharedaix(); "" -}; \
 		a="$(DESTDIR)$(libdir)/$$fn2"; \
 		$(ECHO) "install $$s1 -> $$a"; \
 		if [ -f $$a ]; then ( trap "rm -rf /tmp/ar.$$$$" INT 0; \
@@ -1790,6 +1795,8 @@ EOF
       # libraries for DLLs are a thing.  On platforms that have this mechanism,
       # $import has the name of this import library.  On platforms that don't
       # have this mechanism, $import will be |undef|.
+      # It's also used on AIX in solib mode, which creates import libraries
+      # for the shared libraries.
       my $import = platform->sharedlib_import($args{lib});
       # $simple is for platforms where full shared library names include the
       # shared library version, and there's a simpler name that doesn't include
@@ -1850,9 +1857,18 @@ EOF
           }
       }
       if (defined $import) {
+          if (sharedaix_solib()) {
+              $recipe .= <<"EOF";
+$import: $full $defs[0]
+	rm -f $import && \\
+	echo \\#!$full > $import && \\
+        cat $defs[0] >>$import
+EOF
+          } else {
       $recipe .= <<"EOF";
 $import: $full
 EOF
+          }
       }
       $recipe .= <<"EOF";
 $full: $fulldeps

util/mkdef.pl

@@ -117,6 +117,7 @@ my %OS_data = (
     aix         => { writer     => \&writer_aix,
                      sort       => sorter_unix(),
                      platforms  => { UNIX                       => 1 } },
+    "aix-solib" => 'aix',       # alias
     VMS         => { writer     => \&writer_VMS,
                      sort       => OpenSSL::Ordinals::by_number(),
                      platforms  => { VMS                        => 1 } },