Configure - Get rid of the special thread_cflag, replace with thread_scheme

The thread_cflag setting filled a double role, as kinda sorta an
indicator of thread scheme, and as cflags.  Some configs also added
lflags and ex_libs for multithreading regardless of if threading would
be enabled or not.

Instead of this, add threading cflags among in the cflag setting,
threading lflags in the lflag setting and so on if and only if threads
are enabled (which they are by default).

Also, for configs where there are no special cflags for threading (the
VMS configs are of that kind), this makes it possible to still clearly
mention what thread scheme is used.

The exact value of thread scheme is currently ignored except when it's
"(unknown)", and thereby only serves as a flag to tell if we know how
to build for multi-threading in a particular config.  Yet, the
currently used values are "(unknown)", "pthreads", "uithreads" (a.k.a
solaris threads) and "winthreads".

Reviewed-by: Andy Polyakov <appro@openssl.org>

1 files changed, 52 insertions, 37 deletions

diff --git a/Configure b/Configure
index eab3c661d2..c1a3f8a26e 100755
--- a/Configure
+++ b/Configure
@@ -124,7 +124,7 @@ my $strict_warnings = 0;
 # which has to be accompanied by explicit -D_THREAD_SAFE and
 # sometimes -D_REENTRANT. FreeBSD 5.x expands it as -lc_r, which
 # seems to be sufficient?
-my $BSDthreads="-pthread -D_THREAD_SAFE -D_REENTRANT";
+our $BSDthreads="-pthread -D_THREAD_SAFE -D_REENTRANT";
 
 #
 # API compability name to version number mapping.
@@ -208,7 +208,7 @@ $config{cross_compile_prefix}="";
 $config{fipslibdir}="/usr/local/ssl/fips-2.0/lib/";
 my $nofipscanistercheck=0;
 $config{baseaddr}="0xFB00000";
-my $threads=0;
+my $auto_threads=1;    # enable threads automatically? true by default
 my $default_ranlib;
 $config{fips}=0;
 
@@ -569,6 +569,8 @@ foreach (@argvcopy)
                         {
                         $disabled{$1} = "option";
                         }
+		# No longer an automatic choice
+		$auto_threads = 0 if ($1 eq "threads");
 		}
 	elsif (/^enable-(.+)$/)
 		{
@@ -583,7 +585,8 @@ foreach (@argvcopy)
 		my $algo = $1;
 		delete $disabled{$algo};
 
-		$threads = 1 if ($algo eq "threads");
+		# No longer an automatic choice
+		$auto_threads = 0 if ($1 eq "threads");
 		}
 	elsif (/^--strict-warnings$/)
 		{
@@ -928,32 +931,6 @@ if (!$disabled{dso} && $target{dso_scheme} ne "")
 		}
 	}
 
-my $thread_cflags = "";
-my @thread_defines;
-if ($target{thread_cflag} ne "(unknown)" && !$disabled{threads})
-	{
-	# If we know how to do it, support threads by default.
-	$threads = 1;
-	}
-if ($target{thread_cflag} eq "(unknown)" && $threads)
-	{
-	# If the user asked for "threads", [s]he is also expected to
-	# provide any system-dependent compiler options that are
-	# necessary.
-	if ($no_user_cflags && $no_user_defines)
-		{
-		print "You asked for multi-threading support, but didn't\n";
-		print "provide any system-specific compiler options\n";
-		exit(1);
-		}
-	push @thread_defines, "OPENSSL_THREADS";
-	}
-else
-	{
-	$thread_cflags=" $target{thread_cflag}";
-	push @thread_defines, @{$target{thread_defines}}, "OPENSSL_THREADS";
-	}
-
 $config{ex_libs}="$libs$config{ex_libs}" if ($libs ne "");
 
 if ($disabled{asm})
@@ -962,12 +939,37 @@ if ($disabled{asm})
 	    if ($config{fips});
 	}
 
-if ($threads)
-	{
-	$config{cflags} = "$thread_cflags $config{cflags}" if $thread_cflags;
-	push @{$config{defines}}, @thread_defines;
-	push @{$config{openssl_thread_defines}}, @thread_defines;
-	}
+# If threads aren't disabled, check how possible they are
+unless ($disabled{threads}) {
+    if ($auto_threads) {
+        # Enabled by default, disable it forcibly if unavailable
+        if ($target{thread_scheme} eq "(unknown)") {
+            $disabled{threads} = "unavailable";
+        }
+    } else {
+        # The user chose to enable threads explicitely, let's see
+        # if there's a chance that's possible
+        if ($target{thread_scheme} eq "(unknown)") {
+            # If the user asked for "threads" and we don't have internal
+            # knowledge how to do it, [s]he is expected to provide any
+            # system-dependent compiler options that are necessary.  We
+            # can't truly check that the given options are correct, but
+            # we expect the user to know what [s]He is doing.
+            if ($no_user_cflags && $no_user_defines) {
+                die "You asked for multi-threading support, but didn't\n"
+                    ,"provide any system-specific compiler options\n";
+            }
+        }
+    }
+}
+
+# If threads still aren't disabled, add a C macro to ensure the source
+# code knows about it.  Any other flag is taken care of by the configs.
+unless($disabled{threads}) {
+    foreach (("defines", "openssl_thread_defines")) {
+        push @{$config{$_}}, "OPENSSL_THREADS";
+    }
+}
 
 # With "deprecated" disable all deprecated features.
 if (defined($disabled{"deprecated"})) {
@@ -1833,7 +1835,7 @@ print <<"EOF";
 Configured for $target.
 EOF
 
-print <<"EOF" if (!$disabled{threads} && !$threads);
+print <<"EOF" if ($disabled{threads} eq "unavailable");
 
 The library could not be configured for supporting multi-threaded
 applications as the compiler options required on this system are not known.
@@ -1903,6 +1905,7 @@ sub asm {
     }
 }
 
+our $add_called = 0;
 # Helper function to implement adding values to already existing configuration
 # values.  It handles elements that are ARRAYs, CODEs and scalars
 sub _add {
@@ -1931,6 +1934,8 @@ sub _add {
 	    }
     } (@_);
 
+    $add_called = 1;
+
     if ($found_array) {
 	[ @values ];
     } else {
@@ -1999,6 +2004,8 @@ sub resolve_config {
     my $target = shift;
     my @breadcrumbs = @_;
 
+    my $extra_checks = defined($ENV{CONFIGURE_EXTRA_CHECKS});
+
     if (grep { $_ eq $target } @breadcrumbs) {
 	die "inherit_from loop!  target backtrace:\n  "
 	    ,$target,"\n  ",join("\n  ", @breadcrumbs),"\n";
@@ -2061,6 +2068,8 @@ sub resolve_config {
 	my $target    = shift;
 	my $entry     = shift;
 
+        $add_called = 0;
+
         while(ref($object) eq "CODE") {
             $object = $object->(@$inherited);
         }
@@ -2068,6 +2077,7 @@ sub resolve_config {
             return ();
         }
         elsif (ref($object) eq "ARRAY") {
+            local $add_called;  # To make sure recursive calls don't affect it
             return [ map { process_values($_, $inherited, $target, $entry) }
                      @$object ];
         } elsif (ref($object) eq "") {
@@ -2079,6 +2089,7 @@ sub resolve_config {
     }
 
     foreach (sort keys %all_keys) {
+        my $previous = $combined_inheritance{$_};
 
 	# Current target doesn't have a value for the current key?
 	# Assign it the default combiner, the rest of this loop body
@@ -2093,6 +2104,10 @@ sub resolve_config {
         unless(defined($table{$target}->{$_})) {
             delete $table{$target}->{$_};
         }
+        if ($extra_checks &&
+            $previous && !($add_called ||  $previous ~~ $table{$target}->{$_})) {
+            warn "$_ got replaced in $target\n";
+        }
     }
 
     # Finally done, return the result.
@@ -2167,7 +2182,6 @@ sub print_table_entry
 	"cc",
 	"cflags",
 	"defines",
-	"thread_cflag",
 	"unistd",
 	"ld",
 	"lflags",
@@ -2190,6 +2204,7 @@ sub print_table_entry
 	"cmll_obj",
 	"modes_obj",
 	"padlock_obj",
+	"thread_scheme",
 	"perlasm_scheme",
 	"dso_scheme",
 	"shared_target",